To study the effect of adding Fe2O3 nanoparticles on the morphology properties and microstructure of
10篇英语阅读-带翻译题目答案版
OneYou must have been troubled by when to say "I love you" because it is one of the greatest puzzles in our life.What if you say it first and your partner doesn‟ t love you back? or if they do say. it but you don‟t feel they mean it? Being the first to declare your love can be nerver racking(紧张）and risky and can leave you feeling as vulnerable as a turtle with no shell. But is the person who says it first really in a position of weakness? Doesn‟ t it pay to hold back, play it cool and wait until the oth er half has shown their hand fast?A really good relationship should be about being fair and being equal," says psychologist Sidney Crown. "But love is seldom equal. " All. relationships go through power struggles but, he says, if a love imbalance contin ues for years, the rot will set in. "That feeling of ‟ I‟ ve always loved you more‟ may be subverted(颠覆，破坏) for a time, but it never goes away completely and it often emerges in squabbling(大声争吵). " In love, at least, the silent, withholding type is not always the most powerful. "The strongest one in a relationship is often the person who feels confident enough to talk about their feelings," says educational psychologist Ingrid Collins. Psychosexual therapist Paula Hall agrees. "The one with the upper hand i s often the person who takes the initiative. In fact, the person who says ‟ I love you‟ first may also be the one who says ‟ I‟ m bored with you‟ first. " Hall believes that much depends on how "I love you" is said and the motivation of the person saying i t. "Is it said when they‟ re drunk? Is it said. before their partner files off on holiday, and what it really means is ‟ Please don‟ t be unfaithful to me‟ ? By saying ‟ I love you‟, they really saying‟ Do you love me?‟ If so, wouldn‟t it just be more hone st to say mat.Collins agrees that intention is everything. "It‟s not what is said, but how it‟ s said. What it comes down to is the sincerity of the speaker.”51. What is the main idea of this passage?[ A ] The importance of "I love you"[ B ] The meaning of "I love you"[ C ] The time of saying "I love you".[ D ] The place of saying. "I love you"52. In the first sentence the author means that[ A ] it is easy to say "I love you"[ B ] it is hard to say "I love you"[ C ] we have many troubles in our life[ D ] people usually do not know when to say "I love you"53. According to the expert, a good relationship should be[ A ] fair and equal[ B ] fair and kind[ C ] powerful and equal[ D] confident and fair54. In the third paragraph, the phrase "with the upper hand" means[ A ] being low in spirit[ B ] having only one hand[ C ] being active[ D ] being passive55. What is the most important for you to consider when somebody say "I love you"to you?[ A ] The intention.[ B ] The place.[ C ] The time.[ D ] The determination.Text 2 参考译文你一定曾经为何时说“我爱你”而烦恼过，因为这是我们生活中的一大难题。
水泥砂浆膨胀率试验研究
Hans Journal of Civil Engineering 土木工程, 2014, 3, 76-82Published Online May 2014 in Hans. /journal/hjce/10.12677/hjce.2014.33010Experimental Study on Expansion Rate ofCement MortarRenyong Liu, Shouchao JiangCollege of Civil Engineering, Tongji University, ShanghaiEmail: liury0908@Received: Mar. 25th, 2014; revised: Apr. 28th, 2014; accepted: May 3rd, 2014Copyright © 2014 by authors and Hans Publishers Inc.This work is licensed under the Creative Commons Attribution International License (CC BY)./licenses/by/4.0/AbstractThe influence of the proportion of expanding agent and silica fume and the changing of water- binder ratio on expansion rate of the mortar were studied in this paper. The results indicated that the expansion rate of the mortar was enhanced with the increasing of the expansion agent, and reduced with the adding of the silica fume and the decreasing of the water-binder ratio.KeywordsCement Mortar, Expansion Rate, Silica Fume水泥砂浆膨胀率试验研究刘仁勇，蒋首超同济大学土木工程学院，上海Email: liury0908@收稿日期：2014年3月25日；修回日期：2014年4月28日；录用日期：2014年5月3日摘要本文研究了膨胀剂掺量、硅灰掺量、水胶比降低对水泥砂浆膨胀率的影响。
An XRD study of the effect of the SiO2-Na2O ratio on the alkali activation of fly ash
An XRD study of the effect of the SiO 2/Na 2O ratioon the alkali activation of fly ashM.Criado a ,A.Fernández-Jiménez a,⁎,A.G.de la Torre b ,M.A.G.Aranda b ,A.Palomo aaEduardo Torroja Institute (CSIC),c/Serrano Galvache,no.4,28033Madrid,SpainbDepartment of Inorganic Chemistry,University of Málaga,Campus Teations s/n,29071Málaga,SpainReceived 13November 2006;accepted 26January 2007AbstractSoluble silica has a very significant effect on the microstructural and mechanical development of the cementitious materials produced as a result of the alkali activation of fly ash.In this study,four different alkaline solutions with different soluble silica contents were used to activate fly ash.The primary reaction product was a sodium aluminosilicate gel,while different types of zeolites appeared as minority phases.The percentage and composition of these reaction products were found to depend on both the soluble silica content present in the activating solutions and the thermal curing time.In addition,the amount of gel was observed to have a decisive effect on the mechanical strength developing in the material.©2007Elsevier Ltd.All rights reserved.Keywords:Fly ash;Rietveld method;Silicate –sodium oxide ratio1.IntroductionIn 1959,V.D.Glukhovshy [1]suggested that the construc-tion industry could benefit from the use of what he called “soil cements ”,new cementitious products resulting from attacking certain (natural or industrial waste)aluminosiliceous materials with alkaline salt solutions.The fly ash produced in steam power plants is one such aluminosilicate suitable for alkali activation [2].Although the mechanisms that regulate the reactions between alkaline activator and fly ash are not fully understood,the models that are gradually being developed afford a fairly precise view of what actually takes place [3,4].The activation rate and chemical composition of the reaction products depend on factors such as ash particle size and chemical composition,type and concentration of the activator,etc.Nonetheless,the mechanisms that control the general activation process are independent of the values assumed by these variables at any given time.The above findings informed the decision to conduct the present study on the effect of the soluble silicacontent in the activating solution on the reaction rate of the “ash-activator ”system and the nature of the reaction products.Prior research [5–7]had shown that the H 2O/SiO 2and OH −/SiO 2ratios have a considerable impact on the “molecular ”or “polymeric ”species present in the reaction mix and the rate of uptake of these species into the three-dimensional structure of the tectosilicates.The main reaction product of the alkali activation of fly ash is a sodium aluminosilicate gel.This amorphous material has hitherto been very difficult to characterize,but the understand-ing of its structure and composition is growing steadily more precise with the increasingly powerful analytical techniques now deployed.According to NMR findings,it does,however,exhibit short-range order,with a three-dimensional structure in which silicon is found in a variety of environments,Q 4(nAl):on this basis,the gel can be regarded to be a “zeolite precursor ”[4].Rietveld methodology consists on the comparison between the measured and calculated powder diffraction patterns.The analysis of the whole pattern minimises the inaccuracies derived of systematic errors inside the raw data such as peaks overlap,preferred orientation(s),peak broadening and lack of a pure standard(s).The Rietveld method is a powerful tool to successfully carry out quantitative phase analysis (QPA)ofCement and Concrete Research 37(2007)671–679⁎Corresponding author.E-mail address:pesfj18@ietcc.csic.es (A.Fernández-Jiménez).0008-8846/$-see front matter ©2007Elsevier Ltd.All rights reserved.doi:10.1016/j.cemconres.2007.01.013crystalline complex systems[8–13]although the crystal structures of all crystalline phases must be known.This methodology is also suited to follow structural changes[14,15] due to different elemental composition.Moreover,the Rietveld methodology has also been extended to indirectly determine the amorphous content in a given crystalline sample by adding a suitable standard[16].The aim of the present study was to explore the effect of the soluble silica content in a series of activating solutions on the microstructural development of“ash-activator”system reaction products,and to identify and quantify such products and their impact on mechanical development in the material.2.Experimental2.1.Characterization of initial materialsA type F(as defined in ASTM standard C6128–03)fly ash from the Compostilla steam power plant in Spain,consisting primarily of SiO2and Al2O3was used in the present study.The chemical composition of the ash(determined as described in Spanish standard UNE80–230–99)and percentage of reactive silica(established following the procedure set out in Spanish standard UNE80–225–93)are shown in Tables1and2, respectively.Ninety two per cent of the particles in this ash were b45μm[17].The ash was activated with a series of alkaline solutions, all with a practically constant sodium oxide content(≈8%), but with varying proportions of soluble silica.The products used to prepare the solutions were laboratory reagents:ACS-ISO98%pure NaOH pellets supplied by Panreac S.A.and sodium silicate with a density of1.38g/cc with the following composition:8.2%Na2O;27%SiO2and64.8%H2O.The chemical composition and certain other properties of each solution are given in Table3,which also shows the differences in both the silica and the water content achieved by mixing sodium silicate and sodium hydroxide in different proportions.2.2.Methodology2.2.1.Alkali activation of fly ashThe ash was mixed with the activating solutions described in Table3to prepare prismatic paste specimens(1×1×6cm).The “solution/ash”ratio used was0.4by weight.Specimens were cured at85°C for:8h,7,28,60,90or180days.The humidity was kept at N90%at all times.The activated ash specimens were subjected to standard cement strength tests(as per European code EN196–1)at the different reaction times(12 prisms per test were tested).After each experiment,the material was grinded(size b65μ) and mixed with a small volume of acetone in order to dehydrate the system and then to prevent the material evolution.2.2.2.Determination of the percentage of reaction productsThe hardened pastes were attacked with1:20HCl(by volume) to determine the percentage of reaction products generated at the respective reaction times(the HCl used to prepare the solutions 1:20was hydrochloric acid37%PA-ACS-ISO).This procedure separates the reaction products(sodium aluminosilicate gel and zeolites)which are dissolved in the acid,from the unreacted ash, which remains in the insoluble residue[18,19].The dissolved fraction is a parameter that provides information on the conversion factorα,i.e.,how far the reaction has progressed.The experimental process followed consisted on placing1g of the ground(to a powder,particle size b65μm)hardened material(activated ash)in a250-ml flask containing1:20HCl. The mix was stirred with a plastic rotor for3h,after which it was filtered(through filter paper with a pore size of15–20μm) and the insoluble residue was washed with deionised water to a neutral pH.The filter paper containing the residue was placed in a previously weighed platinum crucible,dried on a heat plate and calcined at1000°C in a furnace for1h.The percentage of the dissolved phases was deduced from the weight loss.The conversion factor or“α”and“IR”or the insoluble residue were determined with Eqs.(1)and(2).IR kðÞ¼P finalP initialÂ100ð1Þa kðÞ¼100−IR kðÞð2Þwhere P initial is the initial weight of the sample;P final is the final weight of the insoluble residue after the HCl attack and calcination at1000°C;IR is the unreacted percentage of fly ash (insoluble residue)andαis the percentage of reaction product.2.2.3.Sample preparation for amorphous quantitative phase analysisAn external standard was added to all the samples in order to carry out the quantification of amorphous content by theTable1Elemental composition of Compostilla fly ash,expressed as oxides(%)SiO2Al2O3Fe2O3CaO MgO SO3Na2O K2O TiO2L.O.I a IR b Total53.0924.808.01 2.44 1.940.230.73 3.78 1.07 3.590.32100.00a L.O.I.loss on ignition;b IR insoluble residue.Table2Reactive silica content in Compostilla fly ash(%)IR a(KOH+HCl)S.R.b TotalSiO2Not reactiveSiO2ReactiveSiO2Fly ash15.5684.4453.09 2.6550.44a IR insoluble residue.b S.R.soluble residue.672M.Criado et al./Cement and Concrete Research37(2007)671–679Rietveld method.The chosen standard wasα-Al2O3.To obtain this standardγ-Al2O3(ALFA,99.997%pure)was ground in an agate ball mill at200rpm for30min.The solid was then heated at1500°C for6h in a Pt crucible.The resulting powder was sieved(b0.125mm)prior to be weighed.All the samples(original and activated ashes)were mixed with a well known amount of standard as described in[18]. 2.3.X-ray powder diffraction data collectionLaboratory XRPD patterns were recorded in a Bragg–Brentano(reflection)X'Pert MPD PRO diffractometer(PANa-lytical)using CuKα1radiation(λ=1.54059Å),[Ge(111) primary monochromator].The optics used were a fixed divergence slit(1/2°),a fixed incident anti-scatter slit(1°),a fixed diffracted anti-scatter slit(1/2°)and an X'Celerator RTMS (Real Time Multiple Strip)detector,working in scanning mode with maximum active length.The samples were rotated during data collection at16rpm in order to enhance particle statistics.The X-ray tube worked at45kV and35mA.The data were collected from10°to70°(2h)during∼15min for the original and activated ashes in order to follow activation process.On the other hand,all the artificial mixtures patterns,i.e.ash withα-Al2O3,were recorded in the same angular range but during∼2h in order to perform Rietveld QPA,including amorphous content determination.3.Results3.1.Mechanical strengthFig.1shows the variation in compressive strength with curing time for the various working systems(12prisms per test were tested).At short curing times(8h),an increase in the soluble silica content(W50and W84)favoured the development of high mechanical strength in the material(compressive strength N30MPa),with values of up to double the strength recorded in matrices activated with solutions with a lower silica content(N and W15,≈15MPa).At slightly longer curing times(20h),however,a substantial increase was observed in the strength of systems with a lower silica content (N and W15),which equalled or even out-performed the other two systems(compressive strength N40MPa)in this regard. Longer curing times had a consistently beneficial effect on the mechanical strength of all the matrices studied throughout the six-month duration of the experiment,with final compressive strength values greater than70MPa in all cases.3.2.Selective phase dissolutionAs explained in the experimental section,a1:20(by volume) HCl attack was used to determine the percentage of reaction product and unreacted fly ash in the material at any given time.Fig.2shows the variation in degree of reaction with curing time for the various working systems.Alpha values were observed to increase with curing time in all the systems studied. One rather striking finding was the lower degree of reaction obtained for system W84at all ages,despite the high mechanical strength obtained(see Fig.1).The reasons underlying this behaviour are explained in greater detail below.3.3.XRD mineralogical analysis.Rietveld quantitative amor-phous content determinationX-ray powder diffraction patterns for all the materials studied,including the original fly ash,are shown in Fig.3. Although fly ash is an essentially vitreous material(see halo recorded for2Θ=20–35°),it also contains a series of minority crystalline phases such as quartz(SiO2,JCPDS05–0492), mullite(3Al2O3.2SiO2,JCPDS15–0776)and magnetite (Fe3O4,JCPDS19–0629).The diffraction pattern changed appreciably after the activation of the original fly ash with the different solutions.It has to be highlighted the shift in the position of the halo attributed to the vitreous phase in the initial ash to slightly higher angular values(2Θ=25–40°).This effect is indicating the formation of an alkaline aluminosilicate gel [17].The crystalline phases(quartz,mullite and magnetite) detected in the initial material remained apparently unaltered with activation.Other zeolite-type crystalline phases also appeared after activation,which varied depending on the nature of the activating solution used and curing time.X-ray powder patterns for fly ash samples alkali activated with solution N are given in Fig.3,upper-left side.These specimens were found to contain zeolite species such ashydrated Fig.1.Mechanical strength vs curing time for the various working systems.Table3Chemical composition and properties of the working solutionsSolution Chemicalcomposition(%of oxides)SiO2/Na2OpH aρb(g/cm3)[OH−]c(M)Na2O SiO2H2ON7.81092.19013.93 1.277.6W158.41 1.6289.970.1913.83 1.358.6W507.84 5.4086.760.6913.81 1.438.5W847.729.0783.21 1.1714.04 1.579.3a Measured with a Metrohm pH meter.b Measured with a pycnometer.c Titrated with HCl.673M.Criado et al./Cement and Concrete Research37(2007)671–679sodalite (also known as hydroxysodalite [20])(Na 4Al 3Si 3O 12OH,JCPDS 11–0401)with an Si/Al ratio=1and Na-chabazite (also known as herschelite [20])(NaAlSi 2O 6·3H 2O,JCPDS 19–1178)with an Si/Al ratio=2.The amount of hydrated sodalite-type zeolite formed was observed to remain practically unchanged throughout the test,while the Na-chabazite content increased withcuring time.Zeolite species such as hydrated sodalite and Na-chabazite were also identified on the W15patterns,see Fig.3,upper-right side.Here the amount of hydrated sodalite-type zeolite crystallizing was likewise found to remain constant throughout,while the Na-chabazite-type content grew with curing time (as in the preceding case);the higher proportion of silica in the reaction environment was observed to favour the early crystallization of Na-chabazite (after only 8h).X-ray powder patterns for fly ash samples alkali activated with solution W50are also shown in Fig.3,bottom-left side.An increase in the soluble silica content in the reaction environment quite clearly induced a delay in the formation of zeolite species.Zeolite Y (Na 1.88Al 2Si 4.8O 13.54·9H 2O,JCPDS 38–0239),with a Si/Al ratio =2.4,for instance,was not detected until the 28th day of treatment.Moreover,while the amount of this species increased with curing time up to 90days,after 180days the predominant zeolite species were Na-chabazite and zeolite P (Na 3.6Al 3.6Si 12.4O 32·12H 2O,JCPDS 40–1464)with an Si/Al ratio of 3.4.These changes can be explained by the fact that zeolites are metastable and may undergo successive transfor-mation into one or several more stable phases.Species with a very open structure convert to closed structure zeolites that eventually form analcime (the most stable and densestofFig.3.X-ray powder diffraction patterns of Compostilla fly ash and activated ashes with different alkaline solutions.Main peaks due to a given phase have beenlabelled.Fig.2.Conversion factor,“α”,vs curing time for the various working systems.674M.Criado et al./Cement and Concrete Research 37(2007)671–679common zeolites)[5].The present study yielded similar findings:zeolite Y ,a species with a pore size of 0.8nm,gave way to zeolite P,which has a smaller pore size (0.43nm)[21]alkali.Finally,X-ray powder patterns for fly ash samples alkali activated with solution W84are also displayed in Fig.3,bottom-right side.Here,zeolite P-type phases were observed to be formed.The formation of zeolite species was retarded even further in the presence of the higher silica content in this activating environment than in the preceding solutions.Moreover,zeolite P was not detected until the 28th day,although the content of this crystalline phase grew with curing time.Rietveld QPA was performed for all the artificial mixtures,original or activated fly ashes with α-Al 2O 3.These results were used to indirectly infer the amorphous content of all the samples,as detailed in [16].QPA results,including the amorphous content,are given in Table 4.The amorphous fraction of the material stands for the vitreous component of the unreacted fly ash and the sodium aluminosilicate gel which is the first reaction product of alkali activation.Furthermore,in all the samples studied,the percentage of the amorphous phase was observed to decline over time while the zeolite content rose.The crystal structures used to perform Rietveld refinements were taken from the Inorganic Crystal Structure Database (ICSD).The collection codes for the various structures were:α-Al 2O 373725;quartz 63532;mullite 66263;magnetite 30860;calcite 80869;Na-chabazite 201584;sodalite 72059;zeolite Y 201472;zeolite P 9550;cancrinite 32582and phillipsite 51639.Neither the positional nor the thermal vibration parameters were refined.The parameters optimized were:background coeffi-cients,cell parameters,zero-shift error,peak shape parameters (including anisotropic terms if needed),and phase fractions.A selected range of the Rietveld plot for the initial fly ash mixed with α-Al 2O 3is given in Fig.4(A),where main peaks due to a given phase have been labelled.The same selected range of the Rietveld plots for the mixture of activated fly ash treated with W15solution after a reaction time of 8h with the standard and the activated fly ash treated with W84after 90days with standard are given in Fig.4(B)and (C)respectively.4.DiscussionThe alkali activation of fly ash is a chemical process in which the vitreous structure of most of its particles is converted into a compact cementitious skeleton [2,22,23].Earlier studies [4,17,24]showed that the main reaction product of the alkali activation of fly ash is a sodium aluminosilicate gel.This aluminosilicate exhibits long-and medium-range disorder,making it amorphous to X-ray diffraction,but at the nanometric level it is found to have a zeolite-type three-dimensional structure [4].One of the most ambitious objectives pursued by researchers (in any line of work)has traditionally been not only to quantitatively monitor but to obtain quantitative control over the chemical reactions involved in the formation of the desired products.In the case of the generation of new cementitiousTable 4Rietveld quantitative phase analysis,including amorphous content,of the initial (Compostilla)and activated fly ash SampleAmorphous a MulliteQuartzMagnetiteCalciteZeolite Na-chabaziteCancrinite Sodalite Y P PhillipsiteFly ash 83.4b 7.08.2 1.4N8h 86.8 3.8 3.90.6 2.10.8 2.0N7d 71.4 1.6 1.50.722.2 1.3 1.3N28d 68.5 1.5 1.20.725.7 1.3 1.1N60d 65.0 1.6 1.30.629.4 1.30.8N90d 60.7 1.5 1.40.733.7 1.30.7N180d 57.1 3.2 2.60.634.2 1.40.9W158h 78.1 5.7 4.50.79.9 1.1W157d 66.0 1.7 1.40.927.3 1.1 1.6W1528d 63.0 1.7 1.40.930.0 1.2 1.8W1560d 63.7 1.8 1.2 1.029.4 1.3 1.6W1590d 57.8 3.5 1.80.933.9 1.30.8W15180d 55.4 3.4 2.00.736.80.90.8W508h 91.2 4.7 3.1 1.0W507d 96.0 1.6 1.60.8W5028d 91.0 1.0 1.50.7 5.7W5060d 89.1 1.0 2.10.77.1W5090d 88.80.6 1.70.68.3W50180d 80.9 2.3 1.50.8 2.32.010.1W848h 91.9 3.6 4.00.4W847d 96.5 1.4 1.80.4W8428d 95.3 1.0 1.40.4 1.10.7W8460d 93.0 1.2 1.50.4 2.3 1.6W8490d 86.2 1.9 1.00.6 1.0 6.1 3.2W84180d83.12.3 1.50.81.26.7 4.4a Amorphous=vitreous phase in the initial ash +sodium aluminosilicate gel (primary reaction product in alkali activation).bAmorphous =vitreous phase in the initial ash.675M.Criado et al./Cement and Concrete Research 37(2007)671–679materials (zeocements or zeoceramics)through the alkali activation of aluminosilicates,this objective has been met by attacking these materials with hydrochloric acid [18,19,25].A step forward in the relevant research prompted the authors of the present paper to quantitatively correlate the type of system studied (with a higher or lower soluble silica content)with the amount of cementitious gel generated and the mechanical properties acquired by the material in response to gel content.An attack with 1:20(by volume)HCl dissolves the reaction products.Consequently,the results obtained from thatattackFig.4.Selected range of the Rietveld plots for the mixtures of α-Al 2O 3with A)original fly ash;B)activated fly ash with W15solution (8h);C)activated fly ash with W84solution (90days).Mu:mullite;Mag:magnetite;Sod:sodalite;Cb:Na-chabazite;Z-Pl:zeolite P;Fp:phillipsite.676M.Criado et al./Cement and Concrete Research 37(2007)671–679(see Fig.2),in conjunction with Rietveld QPA results,can be substituted into Eqs.(3)and (4)to determine the percentage of the vitreous phase still present (Glass),as well as the amount of zeolites (Z)and sodium aluminosilicate gel (Gel)in each of the materials studied.a k ðÞ¼Gel k ðÞþZ k ðÞð3ÞIR k ðÞ¼Glass k ðÞþMu k ðÞþQ k ðÞþFe k ðÞð4ÞWhere αis the conversion factor (%of material dissolved in the 1:20HCl);Gel is the per cent of sodium aluminosilicate gel and Z the percentage of zeolites (calculated with the Rietveld method,see Table 4).IR,in turn,stands for the insoluble residue in 1:20HCl (%insoluble phase,see Fig.2);Glass is the percentage of unreacted vitreous phase;Mu is the percentage of mullite;Q is the percentage of quartz and Fe is the percentage of magnetite (all found with Rietveld methodology,see Table 4).Fig.5shows the variation over time in conversion factor α(i.e.,gel plus zeolites),and vitreous phases present in the initial ash for each and every one of the working systems.The amount of vitreous phase present in the initial ash declined substantially with increasing reaction time in all the systems,since this was the phase that feeds the activation reactions.This decline tapered with time in systems W50and W84;this is pointing out that when soluble silica is highly polymerized,as in the case of solutions W50and W84(see Fig.6)[26],ash dissolution takes place more slowly due to large saturation of the ionic silica species.As mentioned above,the conversion factor α,at any given time is closely related to the amount of gel and zeolites forming in the activated ash.An analysis of the variation in the two phases (gel and zeolites)in each system studied reveals that the percentage of zeolites always grows at the expense of the percentage of gel (see Fig.5).In other words,this may provide confirmation of the hypothesis long sustained that the sodium aluminosilicate gel is a zeolite precursor [27]with a thermodynamic tendency,therefore,to crystallize into a zeolite.Moreover,the highest initial and final mechanical strengths (see Fig.1)were consistently obtained with the systems having higher soluble silica content (W50and W84).That means that the delay in the initial dissolution of the ash (see Fig.2)observed in systems with high percentages of soluble silica and the concomitant deceleration of activation kinetics are offset by the formation of large molecular species and consequently a denser,more compact and stronger gel [28].It might also be reasonably assumed that the energy needed to reorganize these molecules into nanocrystals must be much greater thaninFig.5.Percentage of the different phases comprising the initial and the alkali activated ashes.677M.Criado et al./Cement and Concrete Research 37(2007)671–679systems N and W15and that therefore the amount of zeolites forming in the systems containing a high soluble silica content is much smaller than the amount generated in the other two systems (see Table 4and Fig.5).Systems N and W15were observed to contain the same zeolites:cancrinite ((Na 2O)1.3Al 2O 3(SiO 2)2.01(H 2O)1.65,JCPDS 75–2318)(not labelled in the patterns in Fig.3due to its low percentage),sodalite and Na-chabazite.A small amount of monomeric silica (see Fig.6)has no effect on the type of zeolite formed,although it does hasten reaction kinetics (system W15favours the crystallization of Na-chabazite,the most stable and predominant species under these working conditions).While cancrinite and sodalite form readily under favourable local conditions (in terms of alkalinity and composition),their subsequent crystalline formation or growth is prevented because of the unpropitious conditions (particularly as regards compo-sition)prevailing in the system as an other [6].In the two matrices with an abundance of soluble silica and a higher degree of polymerization,different zeolite species form.Logically,the percentage of zeolites in these systems also grows with time.The amount of zeolite Y ,detected in system W50after 28days,rises up to a reaction time of 90days and then disappears,giving way to Na-chabazite,zeolite P and phillipsite ((K,Na)2(Si,Al)8O 164H 2O,JCPDS 46–1427)(not labelled on the diffracto-grams in Fig.3because the amount is very small and the respective diffraction peaks may overlap with the zeolite P peaks),the species that prevail after 180days.The zeolite species that crystallize in system W84after 28days are zeolite P and phillipsite;the percentage of these zeolites rises with reaction time (see Table 4).Rietveld quantitative analysis reveals that the crystalline phases in the initial ash (quartz,mullite,magnetite)are not as inalterable as the findings of prior studies [24,29,30],but rather undergo minor alterations during the activation pro-cess.Table 4gives the quartz,mullite and magnetite content for all the samples.These results show that while the per-centage of quartz and mullite declined,magnetite did not appear to be impacted by the alkaline attack.These data suggest that the aggressive conditions required for the reaction to take place affected both quartz and mullite,albeit slightly.This observation in fact concurs with prior findings [31],in which a scanning electron microscopic study detected alterations on the surface of mullite crystals.Finally,Fig.7shows the variation in both mechanical strength (A)and the amount of gel formed (B)in terms of the percentage of soluble silica added.Higher strength values were found at all reaction times for system W50,which was,in turn,the system with the highest percentage of gel (see Fig.7),followed by systems W84,N and W15in descending order.The low level of reactivity correlated with high strength in W84series may confirm the hypothesis of P.Duxson et al.,J.Provis et al.[32]by which mechanical strength is likely to be derived from contributions from gel and “aggregated ”materials.Fig.7.Variation in mechanical strength (A)and amount of gel formed (B)versus the percentage of soluble silicaadded.Fig.6.29Si MAS NMR spectra of the liquid activation solutions.678M.Criado et al./Cement and Concrete Research 37(2007)671–679Results show that the mechanical strength development of these types of materials depends not only on the reaction degree (see Fig.2)but also on the nature and composition of the reaction products,the aluminosilicate gel being the main product of reaction inducing the mechanical properties.The higher the amount of this“prezeolite”,the higher the mechanical strength(see Fig.7).On the other hand,a high content of crystalline zeolites prevents the high mechanical strength development.This is the reason why systems N and W15,although having a high conversion factor,develop lower mechanical strength than system W50.5.Conclusions•Upon activation the amount of vitreous phase present in the initial fly ash declines with time,since this is the phase that essentially feeds the activation reaction.•The material owes its good mechanical performance primarily to the sodium aluminosilicate gel.•Zeolites are formed as secondary reaction products.At the present curing temperature of85°C the percentage of zeolites increases with curing time at the expense of the percentage of gel.The inclusion of a greater amount of soluble silica in the environment retards zeolite formation,mainly due to the higher degree of polymerization of such silica.Consequently,systems W50and W84had higher gel content than systems N and W15.•The amount of quartz and mullite slightly declines at longer reaction times.These phases are partially attacked under the aggressive conditions prevailing in such reactions. AcknowledgementsThis study was funded by the Directorate General of Scientific Research(project BIA2004–04835).The Spanish Council for Scientific Research(CSIC)and the European Social Fund co-financed a13P-PC2004L contract in connection with this study.The authors wish to thank J.García and A.Gil for their assistance in the preparation of the specimens. References[1]V.D.Glukhovshy,Soil silicates,Gosstroy publsh,Kiev(Ukraine),1959.[2]A.Palomo,M.W.Grutzeck,M.T.Blanco,Alkali-activated fly ashes.Acement for the future,Cem.Concr.Res.29(1999)1323–1329.[3]A.Fernández-Jiménez,A.Palomo,M.Criado,Microstructure develop-ment of alkali-activated fly ash cement:a descriptive model,Cem.Concr.Res.35(2005)1204–1209.[4]A.Palomo,S.Alonso, A.Fernández-Jiménez,I.Sobrados,J.Sanz,Alkaline activation of fly ashes:NMR study of the reaction products, J.Am.Ceram.Soc.87(2004)1141–1145.[5]A.Dyer“An introduction to zeolite molecular sieves”,Ed.Wiley NewYork(USA),1988.[6]F.R.Ribeiro,A.E.Rodrigues,L.D.Rollmann,C.Naccade,Synthesis ofzeolites:an overview,Zeolites:Science and Techology,Ed.NATO ASI Series80Holand1984109–147.[7]M.Criado,A.Fernández-Jiménez,A.Palomo,Alkali Activation of fly ash.Effect of the SiO2/Na2O ratio.Part I:FTIR study,Microp.Mesop.Mat.(submitted for publication).[8]M.Paul,Application of the Rietveld method in the cement industry,Microstructure Analysis in Materials Science Freiberg(Germany),2005.[9]N.V.Y.Scarlett,I.C.Madsen,L.M.D.Cranswick,T.Lwin,E.Groleau,G.Stephenson,M.Aylmore,N.Agron-Olshina,Outcomes of the international union of crystallography commission on powder diffraction round robin on quantitative phase analysis:samples2,3,4,synthetic bauxite,natural granodiorite and pharmaceuticals,J.Appl.Crystallogr.35(2002)383–400.[10]A.G.de la Torre,A.Cabeza,A.Calvente,S.Bruque,M.A.G.Aranda,Fullphase analysis of Portland clinker by penetrating synchrotron powder diffraction,Anal.Chem.73(2001)151–156.[11]A.G.de la Torre,M.A.G.Aranda,Accuracy in Rietveld quantitative phaseanalysis of Portland cements,J.Appl.Crystallogr.36(2003)1169–1176.[12]I.Pajares,A.G.De la Torre,S.Martínez-Ramírez,F.Puertas,M.T.Blanco-Varela,M.A.G.Aranda,Quantitative analysis of mineralized white Portland clinkers:The structure of Fluorellestadite,Powder Diffr.17 (2002)281–286.[13]A.H.De Aza,A.G.De la Torre,M.A.G.Aranda,F.J.V alle,S.De Aza,Rietveldquantitative analysis of Buen Retiro porcelains,J.Am.Ceram.Soc.87(2004) 449–454.[14]I.Juel,E.Jons,The influence of earth alkalis on the mineralogy in amineralized Portland cement clinker,Cem.Concr.Res.31(2001)893–897.[15]S.J.Barnett,C.D.Adam,A.R.W.Jackson,P.D.Hywel-Evans,Identifica-tion and characterisation of thaumasite by XRPD techniques,Cem.Concr.Compos.21(1999)123–128.[16]A.G.De la Torre,S.Bruque,M.A.G.Aranda,Rietveld quantitativeamorphous content analysis,J.Appl.Crystallogr.34(2001)196–202. [17]A.Fernández-Jiménez,A.Palomo,Characterisation of fly ashes.Potentialreactivity as alkaline cements,Fuel82(2003)2259–2265.[18]A.Fernández-Jiménez,A.G.de la Torre,A.Palomo,G.López-Olmo,M.M.Alonso,M.A.G.Aranda,Quantitative determination of phases in the alkali activation of fly ash.Part I.Potential ash reactivity,Fuel85(2006)625–634.[19]A.Fernández-Jiménez,A.G.de la Torre,A.Palomo,G.López-Olmo,M.M.Alonso,M.A.G.Aranda,Quantitative determination of phases in the alkali activation of fly ash.Part II.Degree of reaction,Fuel85(2006)1960–1969.[20]D.W.Breck,Zeolite molecular sieves,Ed.Krieger Florida(USA),1973.[21]H.V.Bekkum,E.M.Flanigen,P.A.Jacobs,J.C.Jansen,Introduction tozeolite science and practice,Studies in Surface Science and Catalysis,Ed.Elsevier Science BV137Amsterdam(Holland)2001.[22]P.Krivenko,Alkaline cements:terminology,classification,aspects ofdurability,performance and durability of cementitious materials,in:H.Justnes(Ed.),Proc.of10th Int.Cong.Chem.Cem.(ICCC),1997,vol.4 Gothebburg(Sweden).[23]A.Fernández-Jiménez,A.Palomo,Alkali activated fly ashes:propertiesand characteristics,in:G.Grieve,G.Owens(Eds.),Proc.of11th Int.Cong.Chem.Cem.(ICCC)vol.3Durban(South Africa),2003,pp.1322–1340.[24]A.Fernández-Jiménez,A.Palomo,Composition and microstructure ofalkali activated fly ash binder:effect of the activator,Cem.Concr.Res.35 (2005)1984–1992.[25]M.L.Granizo,S.Alonso,M.T.Blanco-Varela, A.Palomo,Alkalineactivation of metakaolin:effect of calcium hydroxide in the products of reaction,J.Am.Ceram.Soc.85(2002)225–231.[26]G.Engelhardt,D.Michel“High Resolution Solid State NMR of silicatesand zeolite”,Ed.Wiley,(1987),London,UK.[27]A.Palomo,F.P.Glasser,Chemically-bonded cementitious materials basedon metakaolin,Br.Ceram.,Trans.J.91(1992)107–112.[28]A.Fernández-Jiménez,A.Palomo,I.Sobrados,J.Sanz,The role played bythe reactive alumina content in the alkaline activation fly ashes,Microp.Mesop.Mat.91(2006)111–119.[29]Z.Xie,Y.Xi,Hardening mechanisms of an alkaline-activated class F flyash,Cem.Concr.Res.31(2001)1245–1249.[30]A.Molina,C.Poole,A comparative study using two methods to producezeolites from fly ash,Miner.Eng.17(2004)167–173.[31]A.Palomo,A.Fernández-Jiménez,M.Criado,“Geopolymers”:same basicchemistry,different microstructures,Mater.Constr.54(2004)77–91. [32]P.Duxson,J.L.Provis,G.C.Lukey,S.W.Mallicoat,W.M.Kriven,J.S.J.van Deventer,Understanding the relationship between geopolymer composition,microstructure and mechanical properties,Colloids Surf.,A 269(2005)47–58.679M.Criado et al./Cement and Concrete Research37(2007)671–679。
剑桥雅思阅读5test2翻译及答案
剑桥雅思阅读5test2翻译及答案雅思阅读是块难啃的硬骨头，需要我们做更多的题目才能得心应手。
下面小编给大家分享一下剑桥雅思阅读5test2原文翻译及答案解析，希望可以帮助到大家。
剑桥雅思阅读5原文(test2)READING PASSAGE 1You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.BAKELITEThe birth of modern plasticsIn 1907, Leo Hendrick Baekeland, a Belgian scientist working in New York, discovered and patented a revolutionary new synthetic material. His invention, which he named ‘Bakelite,’was of enormous technological importance, and effectively launched the modern plastics industry.The term ‘plastic’ comes from the Greek plassein, meaning ‘to mould’. Some plastics are derived from natural sources, some are semi-synthetic (the result of chemical action on a natural substance), and some are entirely synthetic, that is, chemically engineered from the constituents of coal or oil. Some are ‘thermoplastic’, which means that, like candlewax, they melt when heated and can then be reshaped. Others are ‘thermosetting’: like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever. Bakelite had the distinction of being the first totally synthetic thermosetting plastic.The history of today’s plastics begins wit h the discovery of a series of semi-synthetic thermoplastic materials in the mid-nineteenth century. The impetus behind the development ofthese early plastics was generated by a number of factors —immense technological progress in the domain of chemistry, coupled with wider cultural changes, and the pragmatic need to find acceptable substitutes for dwindling supplies of ‘luxury’ materials such as tortoiseshell and ivory.Baekeland’s interest in plastics began in 1885 when, as a young chemistry student in Belgium, he embarked on research into phenolic resins, the group of sticky substances produced when phenol (carbolic acid) combines with an aldehyde (a volatile fluid similar to alcohol). He soon abandoned the subject, however, only returning to it some years later. By 1905 he was a wealthy New Yorker, having recently made his fortune with the invention of a new photographic paper. While Baekeland had been busily amassing dollars, some advances had been made in the development of plastics. The years 1899 and 1900 had seen the patenting of the first semi-synthetic thermosetting material that could be manufactured on an industrial scale. In purely scientific terms, Baekeland’s major contribution to the field is not so much the actual discovery of the material to which he gave his name, but rather the method by which a reaction between phenol and formaldehyde could be controlled, thus making possible its preparation on a commercial basis. On 13 July 1907, Baekeland took out his famous patent describing this preparation, the essential features of which are still in use today.The original patent outlined a three-stage process, in which phenol and formaldehyde (from wood or coal) were initially combined under vacuum inside a large egg-shaped kettle. The result was a resin known as Novalak which became soluble and malleable when heated. The resin was allowed to cool in shallow trays until it hardened, and then broken up and ground intopowder. Other substances were then introduced: including fillers, such as woodflour, asbestos or cotton, which increase strength and moisture resistance, catalysts (substances to speed up the reaction between two chemicals without joining to either) and hexa, a compound of ammonia and formaldehyde which supplied the additional formaldehyde necessary to form a thermosetting resin. This resin was then left to cool and harden, and ground up a second time. The resulting granular powder was raw Bakelite, ready to be made into a vast range of manufactured objects. In the last stage, the heated Bakelite was poured into a hollow mould of the required shape and subjected to extreme heat and pressure, thereby ‘setting’ its form for life.The design of Bakelite objects, everything from earrings to television sets, was governed to a large extent by the technical requirements of the molding process. The object could not be designed so that it was locked into the mould and therefore difficult to extract. A common general rule was that objects should taper towards the deepest part of the mould, and if necessary the product was molded in separate pieces. Moulds had to be carefully designed so that the molten Bakelite would flow evenly and completely into the mould. Sharp corners proved impractical and were thus avoided, giving rise to the smooth, ‘streamlined’ style popular in the 1930s. The thickness of the walls of the mould was also crucial: thick walls took longer to cool and harden, a factor which had to be considered by the designer in order to make the most efficient use of machines.Baekeland’s inve ntion, although treated with disdain in its early years, went on to enjoy an unparalleled popularity which lasted throughout the first half of the twentieth century. It became the wonder product of the new world of industrialsexpansion —‘the material of a thousand uses’. Being both non-porous and heat-resistant, Bakelite kitchen goods were promoted as being germ-free and sterilisable. Electrical manufacturers seized on its insulating properties, and consumers everywhere relished its dazzling array of shades, delighted that they were now, at last, no longer restricted to the wood tones and drab browns of the preplastic era. It then fell from favour again during the 1950s, and was despised and destroyed in vast quantities. Recently, however, it has been experiencing something of a renaissance, with renewed demand for original Bakelite objects in the collectors’ marketplace, and museums, societies and dedicated individuals once again appreciating the style and originality of this innovative material.Questions 1-3Complete the summary.Choose ONE WORD ONLY from the passage for each answer.Write your answers in boxes 1-3 on your answer sheet.Some plastics behave in a similar way to 1……… in that they melt under heat and can be moulded into new forms. Bakelite was unique because it was the first material to be both entirely 2……… in origin, and thermosetting.There were several reasons for the research into plastics in the nineteenth century, among them the great advances that had been made in the field of 3…………a nd the search for alternatives to natural resources like ivory.Questions 4-8Complete the flow-chart.Choose ONE WORD ONLY from the passage for each answer.Write your answers in boxes 4-8 on your answer sheet.The Production of Bakelite图片6Questions 9 and 10Choose TWO letters A-E.Write your answers in boxes 9 and 10 on your answer sheet.NB Your answers may be given in either order.Which TWO of the following factors influencing the design of Bakelite objects are mentioned in the text?A the function which the object would serveB the ease with which the resin could fill the mouldC the facility with which the object could be removed from the mouldD the limitations of the materials used to manufacture the mouldE the fashionable styles of the periodQuestions 11-13Do the following statements agree with the information given in Reading Passage 1?In boxes 11-13 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this11 Modern-day plastic preparation is based on the same principles as that patented in 1907.12 Bakelite was immediately welcomed as a practical and versatile material.13 Bakelite was only available in a limited range of colours.READING PASSAGE 2You should spend about 20 minutes on Questions 14-27, which are based on Reading Passage 2 below.What’s so funny?John McCrone reviews recent research on humorThe joke comes over the headphones: ‘Which side of a dog has the mos t hair? The left.’ No, not funny. Try again. ‘Which side of a dog has the most hair? The outside.’ Hah! The punchline is silly yet fitting, tempting a smile, even a laugh. Laughter has always struck people as deeply mysterious, perhaps pointless. The writer Arthur Koestler dubbed it the luxury reflex: ‘unique in that it serves no apparent biological purpose. ’Theories about humour have an ancient pedigree. Plato expressed the idea that humor is simply a delighted feeling of superiority over others. Kant and Freud felt that joke-telling relies on building up a psychic tension which is safely punctured by the ludicrousness of the punchline. But most modern humor theorists have settled on some version of Aristotle’s belief that jokes are based on a reaction to or resolution of incongruity, when the punchline is either a nonsense or, though appearing silly, has a clever second meaning.Graeme Ritchie, a computational linguist in Edinburgh, studies the linguistic structure of jokes in order to understand not only humor but language understanding and reasoning in machines. He says that while there is no single format for jokes, many revolve around a sudden and surprising conceptual shift. A comedian will present a situation followed by an unexpected interpretation that is also apt.So even if a punchline sounds silly, the listener can see there is a clever semantic fit and that sudden mental ‘Aha!’ is the buzz that makes us laugh. Viewed from this angle, humor is just a form of creative insight, a sudden leap to a new perspective.However, there is another type of laughter, the laughter of social appeasement and it is important to understand this too.Play is a crucial part of development in most young mammals. Rats produce ultrasonic squeaks to prevent their scuffles turning nasty. Chimpanzees have a ‘play-face’ — a gaping expression accompanied by a panting ‘ah ah’ noise. In humans, these signals have mutated into smiles and laughs. Researchers believe social situations, rather than cognitive events such as jokes, trigger these instinctual markers of play or appeasement. People laugh on fairground rides or when tickled to flag a play situation, whether they feel amused or not.Both social and cognitive types of laughter tap into the same expressive machinery in our brains, the emotion and motor circuits that produce smiles and excited vocalisations. However, if cognitive laughter is the product of more general thought processes, it should result from more expansive brain activity.Psychologist Vinod Goel investigated humour using the new technique of ‘single event’ functional magnetic resonance imaging (fMRI). An MRI scanner uses magnetic fields and radio waves to track the changes in oxygenated blood that accompany mental activity. Until recently, MRI scanners needed several minutes of activity and so could not be used to track rapid thought processes such as comprehending a joke. New developments now allow half-second ‘snapshots’ of all sorts of reasoning and problem-solving activities.Although Goel felt being inside a brain scanner was hardly the ideal place for appreciating a joke, he found evidence that understanding a joke involves a widespread mental shift. His scans showed that at the beginning of a joke the listener’s prefrontal cortex lit up, particularly the right prefrontal believed to be critical for problem solving. But there was also activity in the temporal lobes at the side of the head (consistent withattempts to rouse stored knowledge) and in many other brain areas. Then when the punchline arrived, a new area sprang to life — the orbital prefrontal cortex. This patch of brain tucked behind the orbits of the eyes is associated with evaluating information.Making a rapid emotional assessment of the events of the moment is an extremely demanding job for the brain, animal or human. Energy and arousal levels may need to be retuned in the blink of an eye. These abrupt changes will produce either positive or negative feelings. The orbital cortex, the region that becomes active in Goel’s experiment, seems the be st candidate for the site that feeds such feelings into higher-level thought processes, with its close connections to the brain’s sub-cortical arousal apparatus and centres of metabolic control.All warm-blooded animals make constant tiny adjustments in arousal in response to external events, but humans, who have developed a much more complicated internal life as a result of language, respond emotionally not only to their surroundings, but to their own thoughts. Whenever a sought-for answer snaps into place, there is a shudder of pleased recognition. Creative discovery being pleasurable, humans have learned to find ways of milking this natural response. The fact that jokes tap into our general evaluative machinery explains why the line between funny and disgusting, or funny and frightening, can be so fine. Whether a joke gives pleasure or pain depends on a person’s outlook.Humor may be a luxury, but the mechanism behind it is no evolutionary accident. As Peter Derks, a psychologist at William and Mary Colleg e in Virginia, says: ‘I like to think of humour as the distorted mirror of the mind. It’s creative, perceptual, analytical and lingual. If we can figure out how the mindprocesses humor, then we’ll have a pretty good handle on how it works in general.’Questions 14-20Do the following statements agree with the information given in Reading Passage 2?In boxes 14-20 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this14 Arthur Koestler considered laughter biologically important in several ways.15 Plato believed humour to be a sign of above-average intelligence.16 Kant believed that a successful joke involves the controlled release of nervous energy.17 Current thinking on humour has largely ignored Aristotle’s view on the subject.18 Graeme Ritchie’s work links jokes to artificial intelligence.19 Most comedians use personal situations as a source of humour.20 Chimpanzees make particular noises when they are playing.Questions 21-23The diagram below shows the areas of the brain activated by jokes.Label the diagram.Choose NO MORE THAN TWO WORDS from the passage for each answer.Write your answers in boxes 21-23 on your answer sheet.Questions 24-27Complete each sentence with the correct ending A-G below.Write the correct letter A-G in boxes 24-27 on your answer sheet.24 One of the brain’s most difficult tasks is to25 Because of the language they have developed, humans26 Individual responses to humour27 Peter Derks believes that humourA react to their own thoughts.B helped create language in humans.C respond instantly to whatever is happening.D may provide valuable information about the operation of the brain.E cope with difficult situations.F relate to a person’s subjective views.G led our ancestors to smile and then laugh.READING PASSAGE 3You should spend about 20 minutes on Questions 28-40, which are based on Reading Passage 3 below.The Birth of Scientific EnglishWorld science is dominated today by a small number of languages, including Japanese, German and French, but it is English which is probably the most popular global language of science. This is not just because of the importance of English-speaking countries such as the USA in scientific research; the scientists of many non-English-speaking countries find that they need to write their research papers in English to reach a wide international audience. Given the prominence of scientific English today, it may seem surprising that no one really knew how to write science in English before the 17th century. Before that, Latin was regarded as the lingua franca1 for European intellectuals.The European Renaissance (c. 14th-16th century) is sometimes called the ‘revival of learning’, a time of renewed interest in the ‘lost knowledge’ of classical times. At the same time, however, scholars also began to test and extend this knowledge. The emergent nation states of Europe developed competitive interests in world exploration and the development of trade. Such expansion, which was to take the English language west to America and east to India, was supported by scientific developments such as the discovery of magnetism and hence the invention of the compass improvements in cartography and —perhaps the most important scientific revolution of them all —the new theories of astronomy and the movement of the Earth in relation to the planets and stars, developed by Copernicus (1473-1543).England was one of the first countries where scientists adopted and publicised Copernican ideas with enthusiasm. Some of these scholars, including two with interests in language —John Wallis and John Wilkins — helped found the Royal Society in 1660 in order to promote empirical scientific research.Across Europe similar academies and societies arose, creating new national traditions of science. In the initial stages of the scientific revolution, most publications in the national languages were popular works, encyclopaedias, educational textbooks and translations. Original science was not done in English until the second half of the 17th century. For example, Newton published his mathematical treatise, known as the Principia, in Latin, but published his later work on the properties of light — Opticks — in English.There were several reasons why original science continued to be written in Latin. The first was simply a matter of audience. Latinwas suitable for an international audience of scholars, whereas English reached a socially wider, but more local, audience. Hence, popular science was written in English.A second reason for writing in Latin may, perversely, have been a concern for secrecy. Open publication had dangers in putting into the public domain preliminary ideas which had not yet been fully exploited by their ‘author’. This growing concern about intellectual property rights was a feature of the period — it reflected both the humanist notion of the individual, rational scientist who invents and discovers through private intellectual labour, and the growing connection between original science and commercial exploitation. There was something of a social distinction between ‘scholars and gentlemen’ who understood Latin, and men of trade who lacked a classical education. And in the mid-17th century it was common practice for mathematicians to keep their discoveries and proofs secret, by writing them in cipher, in obscure languages, or in private messages deposited in a sealed box with the Royal Society. Some scientists might have felt more comfortable with Latin precisely because its audience, though international, was socially restricted. Doctors clung the most keenly to Latin as an ‘insider language’.A third reason why the writing of original science in English was delayed may have been to do with the linguistic inadequacy of English in the early modern period. English was not well equipped to deal with scientific argument. First it lacked the necessary technical vocabulary. Second, it lacked the grammatical resources required to represent the world in an objective and impersonal way, and to discuss the relations, such as cause and effect, that might hold between complex and hypothetical entities.Fortunately, several members of the Royal Society possessed an interest in Language and became engaged in various linguistic projects. Although a proposal in 1664 to establish a committee for improving the English language came to little, the society’s members did a great deal to foster the publication of science in English and to encourage the development of a suitable writing style. Many members of the Royal Society also published monographs in English. One of the first was by Robert Hooke, the society’s first curator of experiments, who described his experiments with microscopes in Micrographia (1665). This work is largely narrative in style, based on a transcript of oral demonstrations and lectures.In 1665 a new scientific journal, Philosophical Transactions, was inaugurated. Perhaps the first international English-language scientific journal, it encouraged a new genre of scientific writing, that of short, focused accounts of particular experiments.The 17th century was thus a formative period in the establishment of scientific English. In the following century much of this momentum was lost as German established itself as the leading European language of science. It is estimated that by the end of the 18th century 401 German scientific journals had been established as opposed to 96 in France and 50 in England. However, in the 19th century scientific English again enjoyed substantial lexical growth as the industrial revolution created the need for new technical vocabulary, and new, specialized, professional societies were instituted to promote and publish in the new disciplines.lingua franca: a language which is used for communication between groups of people who speak different languages Questions 28-34Complete the summary.Choose NO MORE THAN TWO WORDS from the passage for each answer.Write your answers in boxes 28-34 on your answer sheet.In Europe, modern science emerged at the same time as the nation state. At first, the scientific language of choice remained 28…………… . It allowed scientists to communicate with other socially privileged thinkers while protecting their work from unwanted exploitation. Sometimes the desire to protect ideas seems to have been stronger than the desire to communicate them, particularly in the case of mathematicians and 29…………… . In Britain, moreover, scientists worried that English had neither the 30…………… nor the 31………… to e xpress their ideas. This situation only changed after 1660 when scientists associated with the 32………… set about developing English. An early scientific journal fostered a new kind of writing based on short descriptions of specific experiments. Although English was then overtaken by 33……… , it developed again in the 19th century as a direct result of the 34……………….Questions 35-37Do the following statements agree with the information given in Reading Passage 3?In boxes 35-37 on your answer sheet, writeTRUE if the statement agrees with the informationFALSE if the statement contradicts the informationNOT GIVEN if there is no information on this35 There was strong competition between scientists in Renaissance Europe.36 The most important scientific development of the Renaissance period was the discovery of magnetism.37 In 17th-century Britain, leading thinkers combined their interest in science with an interest in how to express ideas.Questions 38-40Complete the table.Choose NO MORE THAN TWO WORDS from the passage for each answer.Write your answers in boxes 38-40 on your answer sheet.Science written in the first half of the 17th centuryLanguage used Latin EnglishType of science Original 38…………Examples 39………… EncyclopaediasTarget audience International scholars 40…………, but socially wider剑桥雅思阅读5原文参考译文(test2)BAKELITE The birth of modern plastics酚醛塑料——现代塑料的诞生In 1907, Leo Hendrick Baekeland, a Belgian scientist working in New York, discovered and patented a revolutionary new synthetic mater ial. His invention, which he named ‘Bakelite,’ was of enormous technological importance, and effectively launched the modern plastics industry.1907年，比利时科学家Leo Hendrick Baekeland在纽约工作时发现了一种全新的合成材料，并申请了专利。
1 可以金属氧化物
1. INTRODUCTION Ethylene−vinyl acetate copolymer (EVA) is widely used as insulating materials in the wire and cable industry due to its good mechanical and physical properties.1 However, the development and application are greatly limited by its high flammability. In past decades, the halogenated compounds were commonly used as fillers to improve the fire retardancy of EVA.2 Unfortunately, their fire retardant action is accompanied by negative effects, such as the generation of corrosive, obscuring, toxic smoke. In addition, the manufacture and application of some halogen-containing flame retardants are restricted by new regulations, such as the European Directives on WEEE (Waste of Electric and Electronic Equipment, became European Law in February 2003), RHS (Restrictions of Hazardous Substances, became European Law in February 2003), and REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals, entered into force on 1 June 2007). Therefore, there is a growing demand for new, halogenfree flame retardants.3−5 In recent years, intumescent flameretardant (IFR) additives have been widely utilized in the flame retardation of flammable polymers,6−11 because of their low toxicity and low propensity for smoke generation. A typical and widely studied IFR system is composed of ammonium polyphosphate, pentaerythritol, and melamine (APP/PER/ MEL). But adding only IFRs usually requires high content to achieve a good flame retardant rating. A small amount of coadditives often brings significant improvements in thermal stability and flame retardant properties, implying that they can
微生物固化拜耳法赤泥的耐久性研究
林业工程学报，２０２３，８（５）：１６０－１６６ＪｏｕｒｎａｌｏｆＦｏｒｅｓｔｒｙＥｎｇｉｎｅｅｒｉｎｇＤＯＩ：１０．１３３６０／ｊ．ｉｓｓｎ．２０９６－１３５９．２０２３０３００５收稿日期：２０２３－０３－０３㊀㊀㊀㊀修回日期：２０２３－０５－１５基金项目：国家自然科学基金（５１８０９１３９）㊂作者简介：陈龙，男，研究方向为微生物岩土㊂通信作者：刘鹏，男，副教授㊂Ｅ⁃ｍａｉｌ：ｌｉｕｐｅｎｇｒｅａｌ＠ｓｉｎａ．ｃｏｍ微生物固化拜耳法赤泥的耐久性研究陈龙１，刘鹏１，２∗，胡雯璐１，许程１（１．南京林业大学土木工程学院，南京２１００３７；２．江苏省水土保持与生态修复重点实验室，南京２１００３７）摘㊀要：拜耳法赤泥是从铝土矿中提取氧化铝过程产生的固体废弃物，利用微生物加固技术对拜耳法赤泥资源化利用是解决赤泥大规模消纳的有效途径㊂利用微生物注浆加固后的拜尔法赤泥的耐久性，通过研究试样在水稳定性测试㊁干湿循环以及冻融循环测试之后的质量损失率㊁无侧限抗压强度的变化情况，对微生物加固拜耳法赤泥加固效果进行评价㊂结果表明：微生物固化技术对拜耳法赤泥的加固效果良好，通过加入氢氧化钙进一步提高了试样的强度与耐久性㊂在１４ｄ的水稳定性试验中，微生物固化赤泥试样其质量损失率最大仅为２．２９％；添加１０％氢氧化钙的微生物赤泥试样其质量损失率仅为１．１６％，解决了拜耳法赤泥遇水即溃散特性㊂干湿循环试验中，经过１６次干湿循环微生物赤泥试样的质量损失最大为３．２５％，无侧限抗压强度下降了４１．４％；添加１０％氢氧化钙的微生物赤泥试样其质量损失率最大为１．４９％，无侧限抗压强度仅下降了１４．５％㊂冻融循环试验中，冻融循环２次后试样的无侧限抗压强度均有不同程度下降，进一步循环至８次时微生物赤泥试样的抗压强度无明显变化㊂干湿循环对微生物赤泥试样的无侧限抗压强度的降低作用要高于冻融循环㊂试验结果证明，微生物加固可显著提高拜耳法赤泥的力学性质及耐久性，解决其遇水易崩解特性，对利用微生物治理拜耳法赤泥具有重要意义㊂关键词：拜耳法赤泥；微生物加固；抗压强度；干湿循环；冻融循环中图分类号：Ｘ７５８㊀㊀㊀㊀㊀文献标志码：Ａ㊀㊀㊀㊀㊀文章编号：２０９６－１３５９（２０２３）０５－０１６０－０７ＳｔｕｄｙｏｎｔｈｅｄｕｒａｂｉｌｉｔｙｏｆＢａｙｅｒｒｅｄｍｕｄｓｏｌｉｄｉｆｉｅｄｂｙｍｉｃｒｏｏｒｇａｎｉｓｍｓＣＨＥＮＬｏｎｇ１，ＬＩＵＰｅｎｇ１，２∗，ＨＵＷｅｎｌｕ１，ＸＵＣｈｅｎｇ１（１．ＣｏｌｌｅｇｅｏｆＣｉｖｉｌＥｎｇｉｎｅｅｒｉｎｇ，ＮａｎｊｉｎｇＦｏｒｅｓｔｒｙＵｎｉｖｅｒｓｉｔｙ，Ｎａｎｊｉｎｇ２１００３７，Ｃｈｉｎａ；２．ＪｉａｎｇｓｕＰｒｏｖｉｎｃｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＳｏｉｌａｎｄＷａｔｅｒＣｏｎｓｅｒｖａｔｉｏｎａｎｄＥｃｏｌｏｇｉｃａｌＲｅｓｔｏｒａｔｉｏｎ，Ｎａｎｊｉｎｇ２１００３７，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：Ｂａｙｅｒｒｅｄｍｕｄｉｓａｓｏｌｉｄｗａｓｔｅｇｅｎｅｒａｔｅｄｂｙｔｈｅｐｒｏｃｅｓｓｏｆｅｘｔｒａｃｔｉｎｇａｌｕｍｉｎａｆｒｏｍｂａｕｘｉｔｅ，ａｎｄｔｈｅｕｓｅｏｆｍｉｃｒｏｂｉａｌｒｅｉｎｆｏｒｃｅｍｅｎｔｔｅｃｈｎｏｌｏｇｙｆｏｒｔｈｅｒｅｓｏｕｒｃｅｕｔｉｌｉｚａｔｉｏｎｏｆＢａｙｅｒｒｅｄｍｕｄｒｅｓｏｕｒｃｅｓｉｓａｎｅｆｆｅｃｔｉｖｅａｐｐｒｏａｃｈｔｏｓｏｌｖｅｔｈｅｌａｒｇｅ⁃ｓｃａｌｅｐｉｌｉｎｇｉｓｓｕｅｏｆｒｅｄｍｕｄ．Ｉｎｔｈｉｓｓｔｕｄｙ，ｔｈｅｄｕｒａｂｉｌｉｔｙｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＢａｙｅｒｒｅｄｍｕｄｒｅｉｎｆｏｒｃｅｄｂｙｍｉｃｒｏｂｉａｌｇｒｏｕｔｉｎｇｗｅｒｅｓｔｕｄｉｅｄ，ａｎｄｔｈｅｒｅｉｎｆｏｒｃｅｍｅｎｔｅｆｆｅｃｔｏｆＢａｙｅｒｒｅｄｍｕｄｒｅｉｎｆｏｒｃｅｄｂｙｍｉｃｒｏｏｒｇａｎｉｓｍｓｗａｓｅｖａｌｕａｔｅｄｂｙｓｔｕｄｙｉｎｇｔｈｅｃｈａｎｇｅｓｏｆｍａｓｓｌｏｓｓｒａｔｅａｎｄｕｎｃｏｎｆｉｎｅｄｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｏｆｓａｍｐｌｅｓａｆｔｅｒｗａｔｅｒｓｔａｂｉｌｉ⁃ｔｙｔｅｓｔ，ｄｒｙ⁃ｗｅｔｃｙｃｌｅａｎｄｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅｔｅｓｔ．ＴｈｅｒｅｓｕｌｔｓｓｈｏｗｅｄｔｈａｔｔｈｅｍｉｃｒｏｂｉａｌｃｕｒｉｎｇｔｅｃｈｎｏｌｏｇｙｈａｓａｇｏｏｄｒｅｉｎｆｏｒｃｅｍｅｎｔｅｆｆｅｃｔｏｎＢａｙｅｒｒｅｄｍｕｄ，ａｓｗｅｌｌａｓｔｈｅｓｔｒｅｎｇｔｈａｎｄｄｕｒａｂｉｌｉｔｙｏｆｔｈｅｓａｍｐｌｅａｒｅｆｕｒｔｈｅｒｉｍｐｒｏｖｅｄｂｙａｄｄｉｎｇｃａｌｃｉｕｍｈｙｄｒｏｘｉｄｅ．Ｉｎｔｈｅｗａｔｅｒｓｔａｂｉｌｉｔｙｔｅｓｔｆｏｒｕｐｔｏ１４ｄ，ｔｈｅｍａｘｉｍｕｍｍａｓｓｌｏｓｓｒａｔｅｏｆｍｉｃｒｏｂｉａｌｓｏｌｉｄｉｆｉｅｄｒｅｄｍｕｄｓａｍｐｌｅｗａｓｏｎｌｙ２．２９％．Ｔｈｅｍａｓｓｌｏｓｓｒａｔｅｏｆｍｉｃｒｏｂｉａｌｒｅｄｍｕｄｓａｍｐｌｅｃｏｎｔａｉｎｉｎｇ１０％ｃａｌｃｉｕｍｈｙｄｒｏｘｉｄｅｗａｓｏｎｌｙ１．１６％，ｗｈｉｃｈｓｏｌｖｅｓｔｈｅＢａｙｅｒｍｅｔｈｏｄｉｓｓｕｅｏｆｔｈｅｃｏｌｌａｐｓｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒｅｄｍｕｄｗｈｅｎｅｘｐｏｓｅｄｔｏｗａ⁃ｔｅｒ．Ｉｎｔｈｅｄｒｙ⁃ｗｅｔｃｙｃｌｅｔｅｓｔ，ｔｈｅｍａｓｓｌｏｓｓｏｆｍｉｃｒｏｂｉａｌｒｅｄｍｕｄｓａｍｐｌｅａｆｔｅｒ１６ｄｒｙ⁃ｗｅｔｃｙｃｌｅｓｗａｓ３．２５％，ａｎｄｔｈｅｕｎｃｏｎｆｉｎｅｄｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｗａｓｄｅｃｒｅａｓｅｄｂｙ４１．４％．Ｔｈｅｌａｒｇｅｓｔｍａｓｓｌｏｓｓｒａｔｅｏｆｍｉｃｒｏｂｉａｌｒｅｄｍｕｄｓａｍｐｌｅｓｃｏｎｔａｉｎｉｎｇ１０％ｃａｌｃｉｕｍｈｙｄｒｏｘｉｄｅｗａｓ１．４９％，ａｎｄｔｈｅｕｎｃｏｎｆｉｎｅｄｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｗａｓｏｎｌｙｒｅｄｕｃｅｄｂｙ１４．５％．Ｉｎｔｈｅｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅｔｅｓｔ，ｔｈｅｕｎｃｏｎｆｉｎｅｄｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｏｆｔｈｅｓｐｅｃｉｍｅｎｄｅｃｒｅａｓｅｄｔｏｖａｒｙｉｎｇｄｅｇｒｅｅｓａｆｔｅｒｔｗｏｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅｓ，ａｎｄｔｈｅｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｏｆｍｉｃｒｏｂｉａｌｒｅｄｍｕｄｓａｍｐｌｅｄｉｄｎｏｔｃｈａｎｇｅｄｓｉｇｎｉｆｉｃａｎｔｌｙｗｈｅｎｔｈｅｆｕｒｔｈｅｒｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅｗａｓｅｉｇｈｔｔｉｍｅｓ．Ｔｈｅｅｆｆｅｃｔｏｆｄｒｙ⁃ｗｅｔｃｙｃｌｅｏｎｔｈｅｕｎｃｏｎｆｉｎｅｄｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｏｆｍｉｃｒｏｂｉａｌｒｅｄｍｕｄｓａｍｐｌｅｗａｓｈｉｇｈｅｒｔｈａｎｔｈａｔｏｆｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅ．Ｔｈｅｔｅｓｔｒｅｓｕｌｔｓｓｈｏｗｅｄｔｈａｔｍｉｃｒｏｂｉａｌｒｅｉｎｆｏｒｃｅ⁃ｍｅｎｔｃａｎｓｉｇｎｉｆｉｃａｎｔｌｙｉｍｐｒｏｖｅｔｈｅｍｅｃｈａｎｉｃａｌｐｒｏｐｅｒｔｉｅｓａｎｄｄｕｒａｂｉｌｉｔｙｏｆＢａｙｅｒｒｅｄｍｕｄａｎｄｓｏｌｖｅｉｔｓｅａｓｙｄｉｓｉｎｔｅｇｒａ⁃ｔｉｏｎｃｈａｒａｃｔｅｒｉｓｔｉｃｓｉｎｗａｔｅｒ，ｗｈｉｃｈｉｓｏｆｇｒｅａｔｓｉｇｎｉｆｉｃａｎｃｅｆｏｒｔｈｅｕｓｅｏｆｍｉｃｒｏｏｒｇａｎｉｓｍｓｔｏｃｏｎｔｒｏｌＢａｙｅｒｒｅｄｍｕｄ．Ｋｅｙｗｏｒｄｓ：Ｂａｙｅｒｒｅｄｍｕｄ；ｍｉｃｒｏｂｉａｌｒｅｉｎｆｏｒｃｅｍｅｎｔ；ｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈ；ｄｒｙ⁃ｗｅｔｃｙｃｌｅ；ｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅ㊀第５期陈龙，等：微生物固化拜耳法赤泥的耐久性研究㊀㊀拜耳法赤泥是铝土矿制取氧化铝后所残余的工业固体污染性废渣，其氧化铁含量高，故外观呈现为砖红色㊂目前我国赤泥年产量以每年１．０５亿ｔ的速度增长，约占全球增长率的三分之二［１］㊂拜耳法赤泥因其碱性强㊁颗粒直径小㊁化学成分复杂等特性难以在建材领域广泛使用㊂目前赤泥的综合利用率仅为１０％左右［２－３］，大部分仍以赤泥库堆存处理，但随之而来是赤泥堆放占地㊁污染环境和赤泥坝溃塌等诸多风险问题㊂研究大规模资源化利用拜耳法赤泥，对于我国废物再生利用及生态治理具有重大意义㊂由于拜耳法赤泥的强碱特性，许多学者利用赤泥㊁矿渣㊁粉煤灰等材料辅以碱激发剂制成具有高强度的碱激发材料［４－６］㊂在混凝土材料领域，赤泥与水泥生料有十分类似的化学成分，故有些学者将其应用在各种水泥熟料生产的研究中［７－９］㊂上述在消纳拜耳法赤泥的同时存在着成本高㊁不环保等问题㊂微生物诱导碳酸钙沉积加固技术是指某些特殊微生物在其新陈代谢中，不断利用周围环境内的碳源与钙源生成碳酸钙以胶结固化颗粒材料的过程［１０］㊂目前，微生物加固技术在地基土加固［１１］㊁提高地基抗液化能力［１２］㊁污染土治理［１３］以及防尘固沙［１４－１５］方面已有诸多研究㊂邵光辉等［１６］研究菌液浓度㊁胶结液浓度和处理轮数对垃圾焚烧灰渣的强度影响，证明了微生物固化垃圾焚烧灰渣可行且有效㊂陈育民等［１７］通过改造剪切盒装置，实现了在剪切仪上对钙质砂直接进行微生物加固目的，经过微生物加固后的钙质砂其抗剪强度与残余强度高于未加固试样的１．８倍与１．６倍㊂综上，虽然微生物加固土体已有一些研究，但对加固后土体的耐久性研究为之较少㊂拜尔法赤泥中含有大量可溶性强碱物质，在含水量丰富地区和毛细水作用下容易吸水软化，进而引起遇水溶陷的现象㊂故选用巴式芽孢杆菌作为注浆加固菌种，研究微生物加固拜耳法赤泥的水稳定性质，干湿循环以及冻融循环下的强度衰减情况，进而评价微生物注浆加固赤泥的耐久性效果，为微生物加固土体的耐久性研究提供技术参考㊂１㊀材料与方法１．１㊀赤泥基本特性本研究使用的拜耳法赤泥取自中国铝业山东分公司的固体废弃物堆场，其化学成分如表１所示，主要化学成分为Ｆｅ２Ｏ３㊁Ａｌ２Ｏ３㊁ＳｉＯ２㊁Ｎａ２Ｏ，其次为ＣａＯ㊁ＴｉＯ２及少量其他金属氧化物㊂由于赤泥是铝矿石经历一系列破碎㊁粉磨㊁分选等措施得到的产物，其固体颗粒粒径较小且均匀，含水量较高，黏聚力和抗剪强度低，力学性质较差㊂主要物理指标如表２所示，颗粒级配曲线如图１所示㊂表１㊀拜耳法赤泥化学成分Ｔａｂｌｅ１㊀ＣｈｅｍｉｃａｌｃｏｍｐｏｓｉｔｉｏｎｓｏｆＢａｙｅｒ⁃ｐｒｏｃｅｓｓｒｅｄｍｕｄ单位：％ＳｉＯ２质量分数Ｆｅ２Ｏ３质量分数Ａｌ２Ｏ３质量分数Ｎａ２Ｏ质量分数ＣａＯ质量分数ＴｉＯ２质量分数Ｋ２Ｏ质量分数ＭｇＯ质量分数其他成分质量分数２８．１１２８．４６２２．１７１０．３４２．６２１．６５０．１４０．２５６．２６表２㊀拜耳法赤泥的主要物理指标Ｔａｂｌｅ２㊀ＢａｓｉｃｐｈｙｓｉｃａｌｉｎｄｉｃａｔｏｒｓｏｆＢａｙｅｒ⁃ｐｒｏｃｅｓｓｒｅｄｍｕｄ液限／％塑限／％塑性指数／％干密度／（ｇ㊃ｃｍ－３）比重孔隙比ｐＨ渗透系数／（ｃｍ㊃ｓ－１）４３．８２９．２１４．６０．７１２．７９２．９３１２．２５．６ˑ１０－５图１㊀拜耳法赤泥颗粒级配图Ｆｉｇ．１㊀ＰａｒｔｉｃｌｅｇｒａｄａｔｉｏｎｃｕｒｖｅｓｏｆＢａｙｅｒ⁃ｐｒｏｃｅｓｓｒｅｄｍｕｄ１．２㊀矿化微生物的菌种与培养本研究所用菌种为编号ＤＭＳＺ３３的巴氏芽孢杆菌（Ｓｐｏｒｏｓａｒｃｉｎａｐａｓｔｅｕｒｉｉ），购于德国菌种保藏中心（ＤＳＭＺ）㊂培养该试验用菌的营养液采用ＤＳＭＺ推荐的成分配比，营养液成分见表３㊂表３㊀营养液成分Ｔａｂｌｅ３㊀Ｃｏｍｐｏｓｉｔｉｏｎｓｏｆｎｕｔｒｉｅｎｔｓｏｌｕｔｉｏｎ去离子水／ｍＬ尿素／ｇ氯化钠／ｇ大豆蛋白胨／ｇ胰蛋白胨／ｇ１０００２０５５１５㊀㊀具体操作步骤：①将配置好的营养液调节ｐＨ至７．３，放置在高压灭菌锅中以１２１ħ进行高温灭１６１林业工程学报第８卷菌；②将保留的巴氏芽孢杆菌菌种与营养液，按体积比１ʒ８的比例接种至４００ｍＬ的营养液中；③将接种好的菌液放入恒温震荡培养箱中以３０ħ㊁１２０ｒ／ｍｉｎ培养２０ｈ，此时吸光度可以达到２．０左右，脲酶活性（１０．４ １１．７）ｍｍｏｌ／（Ｌ㊃ｍｉｎ）㊂１．３㊀胶结液浓度㊁注浆轮数及外加剂选用胶结液为微生物矿化提供必要的碳源与钙源，此次试验选择的碳源为尿素，钙源为氯化钙㊂尿素与氯化钙质量比为１ʒ１，浓度为１ｍｏｌ／Ｌ，注浆轮数均选择８轮㊂试验用到的外加剂为氢氧化钙，购自国药集团化学试剂有限公司㊂选用氢氧化钙的原因是其对拜耳法赤泥拥有良好的碱激发与离子交换作用㊂１．４㊀制样方法及试验装置制样方法：①首先将拜耳法赤泥放入烘箱中以１０５ħ高温烘２４ｈ，取出后粉碎过２ｍｍ筛；②取内径为３０ｍｍ㊁高为９０ｍｍ的医用针管，在其内壁均匀涂上凡士林；底部塞入橡胶塞，并铺上４层细砂布和１层镍金属网；③取过筛后的赤泥，均匀掺入由设计参数计算出的一定质量氢氧化钙，搅拌均匀；④用电子天平称取７０ｇ土样，均分３份装入针筒分层击实土样，注意每次击实前需对前一层表面刮毛处理，试样高度控制在７０ｍｍ左右（长宽比大于２ʒ１）；⑤制样完成后，先注入一轮纯水，使试样实现饱和即可，接着注入２倍孔隙体积菌液（约４５ｍＬ），等待２４ｈ使细菌充分吸附在土颗粒之间；⑥之后注入１．５倍孔隙体积胶结液（约３５ｍＬ），本试验注浆间隔时间均为２４ｈ，如此重复注入胶结液多轮，直至试验结束，注浆过程结束后，等待２４ｈ并注入２倍孔隙体积的纯水冲洗残留胶结液，蠕动泵流速控制在８７．２８μＬ／ｍｉｎ，对应转速为４．０ｒ／ｍｉｎ；⑦注浆静置完毕后，用拆模刀进行拆样，拆样后放置于烘箱中烘干２４ｈ㊂试验装置见图２㊂图２㊀试验装置示意图Ｆｉｇ．２㊀Ｓｃｈｅｍａｔｉｃｄｉａｇｒａｍｏｆｔｈｅｔｅｓｔｄｅｖｉｃｅ１．５㊀试验方案１．５．１㊀水稳定性试验由于拜耳法赤泥遇水易崩解溃散的特性，加固后赤泥的水稳定性也是加固效果的衡量指标之一㊂采用崩解试验中的质量损失率，对赤泥试样的水稳定性进行评价㊂将注浆加固后的赤泥试样用去离子水进行为期３，７，１４ｄ的浸泡，并对期间土体的剥落状况经行拍照观察㊂１．５．２㊀干湿循环试验反复的干湿循环作用引起赤泥的干缩湿胀，试样内外所产生的应力差会使得试样裂隙增多，而干燥脱湿时，饱和试样内的水分又会沿着孔隙向外蒸发，这就会在一定程度上造成试样表面土颗粒的剥落［１８］㊂本试验采用低温干燥的方式，温度设置为４０ħ㊂对注浆加固后的试样表面拍照观察，对试样进行称质量以作为质量损失计算的初始值；将试样放入烘箱中进行养护，烘箱温度设置为４０ħ，干燥１２ｈ后取出待其冷却至室温，此为１个干循环结束；将试样分别放置于不同的烧杯中，加入去离子水直至试样被完全淹没，液面高于试样３ ４ｃｍ，浸泡１２ｈ，此为１个湿循环结束；１次完整的干湿循环为２４ｈ，各试样组的干湿循环次数分别为４，８，１２，１６次㊂１．５．３㊀冻融循环试验冻融循环试验参考ＧＢ／Ｔ５００８２ ２００９‘普通混凝土长期性能和耐久性能试验方法标准“使用恒温环境箱对试样进行冻融处理㊂对拆模养护后的试样表面观察并拍照，对试样进行称质量以作为质量损失计算的初始值；将试样放置在温度设置为－２０ħ的环境箱中冰冻１２ｈ后，取出置于室温２５ħ环境下融化１２ｈ，此为１个冻融循环周期；１个完整的冻融循环为２４ｈ，各试样组的冻融循环次数分别选为２，４，６，８次，将达到规定次数的试样取出后，对其表面的剥落情况进行观察并拍照，最后进行无侧限强度测试㊂１．６㊀测试方法１．６．１㊀无侧限抗压强度为了研究干湿循环与冻融循环后的强度特性，采用无侧限抗压强度作为评价指标㊂本试验采用电动无侧限抗压仪，荷载精度ʃ０．５％，加载速率为１ｍｍ／ｍｉｎ，计算结果参考ＧＢ／Ｔ５０１２３ ２０１９‘土工试验方法标准“中无侧限抗压强度试验㊂１．６．２㊀质量损失率试样的水稳定性测定和干湿循环试验采用质量法，判断标准根据试样浸水后质量损失率来确定，具体步骤如下：①烧杯洗净后置于烘箱中进行烘干，称取烘干后烧杯的质量为Ｍ１；②将注浆完成后的试样分别用不同的烧杯放置，并置于烘箱中烘２６１㊀第５期陈龙，等：微生物固化拜耳法赤泥的耐久性研究干，直至质量不再变化，称此时质量为Ｍ２；③将烘干后的试样分别浸入装有去离子水的各个烧杯中静置，浸泡时间选择３，７，１４ｄ；④静置１２ｈ后，将未崩解的试样取出，将盛有去离子水和已崩解的土体的烧杯置于烘箱中烘干并称质量为Ｍ３㊂在去离子水中静置规定天数的质量损失率（Ａ１２）的计算式为：Ａ１２＝Ｍ３－Ｍ１Ｍ３－Ｍ２ˑ１００％（１）２㊀结果与分析２．１㊀水稳定性未处理的拜耳法赤泥因其生产工艺影响，其具有遇水易崩解的特性，在刚浸入水中时快速吸收水分，外部就已开始崩解脱落；浸水１ｈ后，未处理的赤泥试样完全溃散，水稳定性极差，质量损失率为１００％（图３）㊂故后续干湿循环㊁冻融循环试验均需要反复浸水测试，未处理赤泥难以进行下列试验㊂图３㊀未处理拜耳法赤泥的水稳定性Ｆｉｇ．３㊀ＷａｔｅｒｓｔａｂｉｌｉｔｙｏｆｕｎｔｒｅａｔｅｄＢａｙｅｒｒｅｄｍｕｄ经过微生物固化后的赤泥试样在水中浸泡数天之后整体未出现明显的解体现象，整体的圆柱形外观保持良好（图４）㊂未添加氢氧化钙的固化试样，其在浸泡１ ３ｄ时变化最大，原本依附在外壁未胶结的土颗粒出现剥落使得水体出现浑浊现象，顶部边缘出现一定的钝化，边缘土体脱落较多㊂添加氢氧化钙的固化试样，浸泡１４ｄ后整体未出现明显变化，仅有少量土颗粒脱落，整体趋于完整㊂各试样的崩解率均较低，试样在浸泡３，７，１４ｄ的崩解率上升缓慢，但可以看出添加氢氧化钙试样的水稳定要明显好于未添加的试样，且１０％掺量的试样也要好于５％掺量的试样（图５），可见其所生成的水化硅铝酸钙在阻止水入侵孔隙时起到积极的作用㊂未添加试样崩解率均维持在低水平，浸泡于水中１４ｄ不产生明显土体崩解损失，水稳定性良好，仅有的部分崩解损失来自上部胶结较弱的区域㊂相较于原始赤泥遇水即崩解，微生物固化作用对于赤泥的水稳定性有很大的改善作用，而氢氧化钙的填量对于ＭＩＣＰ加固后试样的水稳定性起积极作用，对于其抗水侵蚀有较大的提升作用㊂图４㊀不同氢氧化钙掺量试样经浸泡处理后的外观情况Ｆｉｇ．４㊀Ｔｈｅａｐｐｅａｒａｎｃｅｓｏｆｓａｍｐｌｅｓｃｏｎｔａｉｎｉｎｇｄｉｆｆｅｒｅｎｔｃａｌｃｉｕｍｈｙｄｒｏｘｉｄｅｃｏｎｔｅｎｔｓａｆｔｅｒｉｍｍｅｒｓｉｏｎ图５㊀不同浸泡时间试样的质量损失率Ｆｉｇ．５㊀Ｔｈｅｍａｓｓｌｏｓｓｒａｔｅｓｏｆｔｈｅｓａｍｐｌｅｓａｆｔｅｒｄｉｆｆｅｒｅｎｔｉｍｍｅｒｓｉｏｎｔｉｍｅ２．２㊀干湿循环不同氢氧化钙掺量下微生物固化的赤泥试样在不同干湿循环次数后的表观变化见图６，经过４次湿循环后试样表面出现较多的孔洞，但未出现裂缝，试样整体保持良好；经过１６次湿循环后试样表面劣化程度明显加重，孔洞相连部分进一步扩大，局部出现土体成片脱落，但仍然保留原试样的基本形状㊂在干湿循环作用下，固化赤泥的表观破坏程度随干湿循环次数的增加而增加㊂相较于未添加氢氧化钙的固化试样，添加氢氧化钙微生物固化的赤泥试样在不同干湿循环次数后的表观变化不大，试样表面仅出现较多微小孔洞，但试样的整体性较好㊂３６１林业工程学报第８卷图６㊀不同氢氧化钙掺量试样经干湿循环处理后的外观情况Ｆｉｇ．６㊀Ｔｈｅａｐｐｅａｒａｎｃｅｓｏｆｓａｍｐｌｅｓｃｏｎｔａｉｎｉｎｇｄｉｆｆｅｒｅｎｔｃａｌｃｉｕｍｈｙｄｒｏｘｉｄｅｃｏｎｔｅｎｔｓａｆｔｅｒｄｉｆｆｅｒｅｎｔｄｒｙ⁃ｗｅｔｃｙｃｌｅｓ总体上看，所有试样的质量损失率均随着干湿循环次数的增加而增加，氢氧化钙添加量为１０％的微生物固化赤泥试样的质量损失增长幅度最小（图７）㊂经过４次干湿循环后，未添加氢氧化钙试样㊁添加５％氢氧化钙试样和添加１０％氢氧化钙试样的质量分别损失了２．０７％，１．２８％和１．１２％；在长达１６轮干湿循环作用后，未添加氢氧化钙试样㊁添加５％氢氧化钙试样和添加１０％氢氧化钙试样的质量分别损失了３．２５％，２．２５％和１．４９％，试样质量损失达到整个试验过程中的最大值㊂值得注意的是，添加１０％氢氧化钙试样的质量损失率明显低于其他两种试样，且其质量损失率随着干湿循环次数的增加的提升幅度小，也反映出对抵抗干湿循环侵蚀作用的能力强㊂图７㊀不同干湿循环次数下试样的质量损失率Ｆｉｇ．７㊀Ｔｈｅｍａｓｓｌｏｓｓｒａｔｅｓｏｆｔｈｅｓａｍｐｌｅｓａｆｔｅｒｄｉｆｆｅｒｅｎｔｄｒｙ⁃ｗｅｔｃｙｃｌｅｓ随着干湿循环次数的增加，固化赤泥的抗压强度均呈现下降趋势（图８）㊂从未添加氢氧化钙试样的无侧限抗压强度可以看出，在经历４次干湿循环后试样强度就降低了１４％；４ ８次时，强度损失幅度减小；而８ １２次时，强度损失幅度加速扩大，降幅进一步扩大２０％，随后降幅趋于平缓㊂经过４次和８次干湿循环后，赤泥抗压强度分别为１１５３．７４和１１０６．７３ｋＰａ，下降幅度不大；从第８次到第１２次干湿循环，无侧限抗压强度由１１０６．７３ｋＰａ下降到８２８．３７ｋＰａ，相比于干湿循环前强度下降了约３８％㊂从添加１０％氢氧化钙的试样的无侧限抗压强度可以看出，经过４次和８次干湿循环后，赤泥抗压强度分别为２２３１．８７和２２１６．３２ｋＰａ，下降幅度小；从第８次到第１２次干湿循环，无侧限抗压强度由２２１６．３２ｋＰａ下降到２２００．０４ｋＰａ，相比于未干湿循环前强度下降了约１３％；经过１６次干湿循环作用，添加１０％氢氧化钙试样的强度为２１６２．７６ｋＰａ，相比于１２次循环，强度仅下降了２％左右㊂添加１０％氢氧化钙的试样抵抗干湿循环侵蚀的能力要高于前两者㊂随着干湿循环次数的增加，固化赤泥试样的抗压强度不断下降，这是由于试样内部的胶结不均匀性而存在大量孔隙，细小的赤泥颗粒吸水性强，在干湿循环作用下就会造成干缩湿涨的现象，并在结构的薄弱处产生应力集中，这种作用力不断积累直至大于土颗粒之间的黏聚力造成结构性破坏，使得试样的抗压强度降低㊂图８㊀抗压强度随干湿循环次数的变化Ｆｉｇ．８㊀Ｔｈｅｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｖａｒｉｅｓｗｉｔｈｄｉｆｆｅｒｅｎｔｗｅｔ⁃ｄｒｙｃｙｃｌｅｓ２．３㊀冻融循环试件经过冻融循环后表观特征变化显著，随着冻融次数的增加，试件外观会发生不同程度的表面脱落㊁碎屑增多，此外结构致密性也会产生较大影响㊂未掺氢氧化钙的固化赤泥试样经过两个冻融循环后试样表面有轻微的碎屑脱落且表面粗糙；经过８轮冻融循环后，试样外观除表皮有轻微脱落，４６１㊀第５期陈龙，等：微生物固化拜耳法赤泥的耐久性研究与两个冻融循环后的试样无明显差异，也未出现大量颗粒剥落与开裂现象，整体稳定性良好㊂掺入氢氧化钙的固化赤泥试样经过两个冻融循环后试样未出现表皮颗粒脱落现象，同样８轮冻融循环后的试样无明显变化，整体稳定性良好（图９）㊂图９㊀不同氢氧化钙掺量试样经冻融循环处理后的外观情况Ｆｉｇ．９㊀Ｔｈｅａｐｐｅａｒａｎｃｅｓｏｆｓａｍｐｌｅｓｃｏｎｔａｉｎｉｎｇｄｉｆｆｅｒｅｎｔｃａｌｃｉｕｍｈｙｄｒｏｘｉｄｅｃｏｎｔｅｎｔｓａｆｔｅｒｄｉｆｆｅｒｅｎｔｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅｓ图１０㊀抗压强度随冻融循环次数的变化Ｆｉｇ．１０㊀Ｃｏｍｐｒｅｓｓｉｖｅｓｔｒｅｎｇｔｈｖａｒｉｅｓｗｉｔｈｄｉｆｆｅｒｅｎｔｆｒｅｅｚｅ⁃ｔｈａｗｃｙｃｌｅｓ冻融循环次数对赤泥试样抗压性能影响如图１０所示㊂由图１０可知，固化赤泥试样无侧限抗压强度随着冻融循环次数的增加先下降后趋于稳定㊂无论是未掺氢氧化钙的试样还是掺入氢氧化钙的试样的无侧限抗压强度在经历两个冻融循环后强度都有较大程度的下滑㊂经历２轮冻融循环后，氢氧化钙掺量为０％，５％，１０％的赤泥试样无侧限抗压强度分别下降１５．０％，１３．７％，１０．１％；经历８次冻融循环后，氢氧化钙掺量为０％，５％，１０％的赤泥试样无侧限抗压强度相较于２次冻融循环后的抗压强度分别下降１．７８％，１．１２％，１．０４％，可以判断各试样的无侧限抗压强度基本保持恒定㊂３㊀结㊀论本次试验研究微生物固化拜耳法赤泥的耐久性，分析赤泥试样的水温定性㊁干湿循环㊁冻融循环试验中试样的质量损失和抗压强度的变化规律，主要结论如下：１）经过微生物固化后的赤泥试样在水中浸泡数天之后整体未出现明显的解体现象，整体外观保持良好，其在浸泡１ ３ｄ时边缘土体脱落较多㊂添加氢氧化钙的固化试样，浸泡１４ｄ后整体未出现明显变化㊂相较于原始赤泥遇水即崩解，微生物固化作用对于赤泥的水稳定性有很大的改善作用，而氢氧化钙对于ＭＩＣＰ加固后试样的抗水侵蚀有较大的提升作用㊂２）随着干湿循环次数的增加，仅微生物固化赤泥试样的质量损失逐渐增加，固化赤泥的抗压强度均呈现下降趋势㊂添加１０％氢氧化钙试样的质量损失率要优于其他两种试样，且其质量损失率随着干湿循环次数的增加的提升幅度小㊂添加１０％氢氧化钙的试样抵抗干湿循环侵蚀的能力要高于前两者，抵抗干湿循环侵蚀作用的能力强㊂３）冻融循环２次后试样的无侧限抗压强度降低较大，后续无侧限抗压强度随着冻融循环次数增加趋于平稳㊂经过８次冻融循环后，试样外观除表皮有轻微脱落，未出现大量颗粒剥落与开裂现象，整体稳定性良好㊂４）通过对比水稳定性㊁干湿循环㊁冻融循环过程中试样的外观破损㊁质量损失以及无侧限抗压强度变化后发现，干湿循环对试样的破坏影响强于水浸泡和冻融循环㊂参考文献（Ｒｅｆｅｒｅｎｃｅｓ）：［１］ＭＵＫＩＺＡＥ，ＺＨＡＮＧＬＬ，ＬＩＵＸＭ，ｅｔａｌ．Ｕｔｉｌｉｚａｔｉｏｎｏｆｒｅｄｍｕｄｉｎｒｏａｄｂａｓｅａｎｄｓｕｂｇｒａｄｅｍａｔｅｒｉａｌｓ：ａｒｅｖｉｅｗ［Ｊ］．Ｒｅｓｏｕｒｃｅｓ，ＣｏｎｓｅｒｖａｔｉｏｎａｎｄＲｅｃｙｃｌｉｎｇ，２０１９，１４１：１８７－１９９．ＤＯＩ：１０．１０１６／ｊ．ｒｅｓｃｏｎｒｅｃ．２０１８．１０．０３１．［２］ＷＡＮＧＳＨ，ＪＩＮＨＸ，ＤＥＮＧＹ，ｅｔａｌ．ＣｏｍｐｒｅｈｅｎｓｉｖｅｕｔｉｌｉｚａｔｉｏｎｓｔａｔｕｓｏｆｒｅｄｍｕｄｉｎＣｈｉｎａ：ａｃｒｉｔｉｃａｌｒｅｖｉｅｗ［Ｊ］．Ｊｏｕｒ⁃ｎａｌｏｆＣｌｅａｎｅｒＰｒｏｄｕｃｔｉｏｎ，２０２１，２８９：１２５１３６．ＤＯＩ：１０．１０１６／ｊ．ｊｃｌｅｐｒｏ．２０２０．１２５１３６．［３］刘松辉．拜耳法赤泥制备低钙胶凝材料及凝结硬化机理［Ｄ］．焦作：河南理工大学，２０１９：３－１３．ＤＯＩ：１０．２７１１６／ｄ．ｃｎｋｉ．ｇｊｚｇｃ．２０１９．００００１５．ＬＩＵＳＨ．ＰｒｅｐａｒａｔｉｏｎａｎｄｈａｒｄｅｎｉｎｇｍｅｃｈａｎｉｓｍｏｆｌｏｗｃａｌｃｉｕｍｃｅｍｅｎｔｉｔｉｏｕｓｍａｔｅｒｉａｌｍａｄｅｂｙＢａｙｅｒｒｅｄｍｕｄ［Ｄ］．Ｊｉａｏｚｕｏ：ＨｅｎａｎＰｏｌｙｔｅｃｈｎｉｃＵｎｉｖｅｒｓｉｔｙ，２０１９：３－１３．５６１林业工程学报第８卷［４］丁崧，陈潇，夏飞跃，等．净水型赤泥⁃矿渣基地聚合物透水混凝土的研究［Ｊ］．建筑材料学报，２０２０，２３（１）：４８－５５．ＤＯＩ：１０．３９６９／ｊ．ｉｓｓｎ．１００７－９６２９．２０２０．０１．００８．ＤＩＮＧＳ，ＣＨＥＮＸ，ＸＩＡＦＹ，ｅｔａｌ．Ｓｔｕｄｙｏｎｒｅｄｍｕｄ⁃ｓｌａｇｂａｓｅｄｇｅｏｐｏｌｙｍｅｒｐｅｒｖｉｏｕｓｃｏｎｃｒｅｔｅｗｉｔｈｆｕｎｃｔｉｏｎｏｆｗａｔｅｒｐｕｒｉｆｉｃａｔｉｏｎ［Ｊ］．ＪｏｕｒｎａｌｏｆＢｕｉｌｄｉｎｇＭａｔｅｒｉａｌｓ，２０２０，２３（１）：４８－５５．［５］ＣＨＡＮＤＲＡＫＳ，ＫＲＩＳＨＮＡＩＡＨＳ，ＲＥＤＤＹＮＧ，ｅｔａｌ．Ｓｔｒｅｎｇｔｈｄｅｖｅｌｏｐｍｅｎｔｏｆｇｅｏｐｏｌｙｍｅｒｃｏｍｐｏｓｉｔｅｓｍａｄｅｆｒｏｍｒｅｄｍｕｄ⁃ｆｌｙａｓｈａｓａｓｕｂｇｒａｄｅｍａｔｅｒｉａｌｉｎｒｏａｄｃｏｎｓｔｒｕｃｔｉｏｎ［Ｊ］．ＪｏｕｒｎａｌｏｆＨａ⁃ｚａｒｄｏｕｓ，Ｔｏｘｉｃ，ａｎｄＲａｄｉｏａｃｔｉｖｅＷａｓｔｅ，２０２１，２５（１）：４０２００６８．ＤＯＩ：１０．１０６１／（ａｓｃｅ）ｈｚ．２１５３－５５１５．００００５７５．［６］安强，潘慧敏，赵庆新，等．碱激发赤泥⁃粉煤灰⁃电石渣复合材料性能研究［Ｊ］．建筑材料学报，２０２３，２６（１）：１４－２０．ＤＯＩ：１０．３９６９／ｊ．ｉｓｓｎ．１００７－９６２９．２０２３．０１．００３．ＡＮＱ，ＰＡＮＨＭ，ＺＨＡＯＱＸ，ｅｔａｌ．Ｐｒｏｐｅｒｔｉｅｓｏｆａｌｋａ⁃ｌｉａｃｔｉｖａｔｅｄｒｅｄｍｕｄ⁃ｆｌｙａｓｈ⁃ｃａｒｂｉｄｅｓｌａｇｃｏｍｐｏｓｉｔｅｓ［Ｊ］．ＪｏｕｒｎａｌｏｆＢｕｉｌｄｉｎｇＭａｔｅｒｉａｌｓ，２０２３，２６（１）：１４－２０．［７］赵艳荣，陈平，韦怀珺，等．以粉煤灰㊁赤泥低温烧制贝利特⁃硫铝酸盐水泥［Ｊ］．非金属矿，２０１５，３８（２）：２１－２３．ＤＯＩ：１０．３９６９／ｊ．ｉｓｓｎ．１０００－８０９８．２０１５．０２．００７．ＺＨＡＯＹＲ，ＣＨＥＮＰ，ＷＥＩＨＪ，ｅｔａｌ．Ｐｒｅｐａｒｅｄｂｅｌｉｔｅｓｕｌｆｏａｌｕ⁃ｍｉｎａｔｅｃｅｍｅｎｔｕｓｉｎｇｆｌｙａｓｈａｎｄＢａｙｅｒｒｅｄｍｕｄｏｎｌｏｗｔｅｍｐｅｒａｔｕｒｅ［Ｊ］．Ｎｏｎ⁃ＭｅｔａｌｌｉｃＭｉｎｅｓ，２０１５，３８（２）：２１－２３．［８］夏瑞杰，朱建平，刘少雄，等．赤泥和脱硫石膏制备高贝利特硫铝酸盐水泥熟料［Ｊ］．有色金属工程，２０１７，７（６）：５８－６３，７９．ＤＯＩ：１０．３９６９／ｊ．ｉｓｓｎ．２０９５－１７４４．２０１７．０６．０１４．ＸＩＡＲＪ，ＺＨＵＪＰ，ＬＩＵＳＸ，ｅｔａｌ．Ｐｒｅｐａｒａｔｉｏｎｏｆｈｉｇｈｂｅｌｉｔｅｓｕｌｐｈｏａｌｕｍｉｎａｔｅｃｅｍｅｎｔｃｌｉｎｋｅｒｓｕｓｉｎｇｒｅｄｍｕｄａｎｄｄｅｓｕｌｆｕｒｉｚａｔｉｏｎｇｙｐｓｕｍ［Ｊ］．ＮｏｎｆｅｒｒｏｕｓＭｅｔａｌｓＥｎｇｉｎｅｅｒｉｎｇ，２０１７，７（６）：５８－６３，７９．［９］ＫＡＮＧＳＰ，ＫＷＯＮＳＪ．Ｅｆｆｅｃｔｓｏｆｒｅｄｍｕｄａｎｄａｌｋａｌｉ⁃ａｃｔｉｖａｔｅｄｓｌａｇｃｅｍｅｎｔｏｎｅｆｆｌｏｒｅｓｃｅｎｃｅｉｎｃｅｍｅｎｔｍｏｒｔａｒ［Ｊ］．ＣｏｎｓｔｒｕｃｔｉｏｎａｎｄＢｕｉｌｄｉｎｇＭａｔｅｒｉａｌｓ，２０１７，１３３：４５９－４６７．ＤＯＩ：１０．１０１６／ｊ．ｃｏｎｂｕｉｌｄｍａｔ．２０１６．１２．１２３．［１０］ＤＥＪＯＮＧＪＴ，ＳＯＧＡＫ，ＢＡＮＷＡＲＴＳＡ，ｅｔａｌ．Ｓｏｉｌｅｎｇｉｎｅｅｒｉｎｇｉｎｖｉｖｏ：ｈａｒｎｅｓｓｉｎｇｎａｔｕｒａｌｂｉｏｇｅｏｃｈｅｍｉｃａｌｓｙｓｔｅｍｓｆｏｒｓｕｓｔａｉｎａｂｌｅ，ｍｕｌｔｉ⁃ｆｕｎｃｔｉｏｎａｌｅｎｇｉｎｅｅｒｉｎｇｓｏｌｕｔｉｏｎｓ［Ｊ］．ＪｏｕｒｎａｌｏｆｔｈｅＲｏｙａｌＳｏｃｉｅｔｙＩｎｔｅｒｆａｃｅ，２０１１，８（５４）：１－１５．ＤＯＩ：１０．１０９８／ｒｓｉｆ．２０１０．０２７０．［１１］赵志峰，邵光辉．微生物诱导碳酸钙沉积加固海相粉土的试验研究［Ｊ］．应用基础与工程科学学报，２０２１，２９（１）：２３１－２３８．ＤＯＩ：１０．１６０５８／ｊ．ｉｓｓｎ．１００５－０９３０．２０２１．０１．０２０．ＺＨＡＯＺＦ，ＳＨＡＯＧＨ．Ｅｘｐｅｒｉｍｅｎｔａｌｓｔｕｄｙｏｎｍａｒｉｎｅｓｉｌｔｒｅｉｎ⁃ｆｏｒｃｅｍｅｎｔｂｙｍｉｃｒｏｂｉａｌｉｎｄｕｃｅｄｃａｌｃｉｕｍｐｒｅｃｉｐｉｔａｔｉｏｎ［Ｊ］．ＪｏｕｒｎａｌｏｆＢａｓｉｃＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，２０２１，２９（１）：２３１－２３８．［１２］张鑫磊，陈育民，张喆，等．微生物灌浆加固可液化钙质砂地基的振动台试验研究［Ｊ］．岩土工程学报，２０２０，４２（６）：１０２３－１０３１．ＤＯＩ：１０．１１７７９／ＣＪＧＥ２０２００６００５．ＺＨＡＮＧＸＬ，ＣＨＥＮＹＭ，ＺＨＡＮＧＺ，ｅｔａｌ．Ｐｅｒｆｏｒｍａｎｃｅｅｖａ⁃ｌｕａｔｉｏｎｏｆｌｉｑｕｅｆａｃｔｉｏｎｒｅｓｉｓｔａｎｃｅｏｆａＭＩＣＰ⁃ｔｒｅａｔｅｄｃａｌｃａｒｅｏｕｓｓａｎｄｙｆｏｕｎｄａｔｉｏｎｕｓｉｎｇｓｈａｋｅｔａｂｌｅｔｅｓｔｓ［Ｊ］．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＧｅｏｔｅｃｈｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，２０２０，４２（６）：１０２３－１０３１．［１３］邵光辉，戴浩然，郭恒君．微生物固化和稳定化铅污染粉土的强度与污染物浸出特性［Ｊ］．林业工程学报，２０２２，７（５）：１６１－１６８．ＤＯＩ：１０．１３３６０／ｊ．ｉｓｓｎ．２０９６－１３５９．２０２２０２０１１．ＳＨＡＯＧＨ，ＤＡＩＨＲ，ＧＵＯＨＪ．Ｓｔｒｅｎｇｔｈａｎｄｐｏｌｌｕｔａｎｔｌｅａｃｈｉｎｇｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｍｉｃｒｏｂｉａｌｓｏｌｉｄｉｆｉｅｄａｎｄｓｔａｂｉｌｉｚｅｄｌｅａｄ⁃ｃｏｎｔａｍｉ⁃ｎａｔｅｄｓｉｌｔ［Ｊ］．ＪｏｕｒｎａｌｏｆＦｏｒｅｓｔｒｙＥｎｇｉｎｅｅｒｉｎｇ，２０２２，７（５）：１６１－１６８．［１４］刘忠，肖水明，刘飞飞，等．微生物诱导碳酸钙沉积固化建筑渣土抗风蚀扬尘影响因素的试验研究［Ｊ］．工业建筑，２０２２，５２（１１）：７１－７８．ＤＯＩ：１０．１３２０４／ｊ．ｇｙｊｚＧ２２０７０６０９．ＬＩＵＺ，ＸＩＡＯＳＭ，ＬＩＵＦＦ，ｅｔａｌ．Ｅｘｐｅｒｉｍｅｎｔａｌｓｔｕｄｙｏｎｉｎ⁃ｆｌｕｅｎｃｅｆａｃｔｏｒｓｏｆａｎｔｉ⁃ｗｉｎｄｅｒｏｓｉｏｎａｎｄａｎｔｉ⁃ｄｕｓｔｆｏｒｃｏｎｓｔｒｕｃｔｉｏｎｄｅｂｒｉｓｃｅｍｅｎｔｅｄｂｙＭＩＣＰ［Ｊ］．ＩｎｄｕｓｔｒｉａｌＣｏｎｓｔｒｕｃｔｉｏｎ，２０２２，５２（１１）：７１－７８．［１５］ＮＡＥＩＭＩＭ，ＣＨＵＪ．Ｃｏｍｐａｒｉｓｏｎｏｆｃｏｎｖｅｎｔｉｏｎａｌａｎｄｂｉｏ⁃ｔｒｅａｔｅｄｍｅｔｈｏｄｓａｓｄｕｓｔｓｕｐｐｒｅｓｓａｎｔｓ［Ｊ］．ＥｎｖｉｒｏｎｍｅｎｔａｌＳｃｉｅｎｃｅａｎｄＰｏｌｌｕｔｉｏｎＲｅｓｅａｒｃｈ，２０１７，２４（２９）：２３３４１－２３３５０．ＤＯＩ：１０．１００７／ｓ１１３５６－０１７－９８８９－１．［１６］邵光辉，陈相宇，崔小相．微生物固化垃圾焚烧灰渣强度试验［Ｊ］．林业工程学报，２０２０，５（１）：１７１－１７７．ＤＯＩ：１０．１３３６０／ｊ．ｉｓｓｎ．２０９６－１３５９．２０１９０２０２１．ＳＨＡＯＧＨ，ＣＨＥＮＸＹ，ＣＵＩＸＸ．Ｓｔｒｅｎｇｔｈｐｒｏｐｅｒｔｉｅｓｏｆｂｉｏｃｅ⁃ｍｅｎｔｅｄｍｕｎｉｃｉｐａｌｓｏｌｉｄｗａｓｔｅｉｎｃｉｎｅｒａｔｉｏｎａｓｈａｎｄｓｌａｇ［Ｊ］．ＪｏｕｒｎａｌｏｆＦｏｒｅｓｔｒｙＥｎｇｉｎｅｅｒｉｎｇ，２０２０，５（１）：１７１－１７７．［１７］陈育民，张书航，丁绚晨，等．微生物加固钙质砂强度演化过程的环剪试验研究［Ｊ］．土木与环境工程学报（中英文），２０２２，４４（４）：１０－１７．ＣＨＥＮＹＭ，ＺＨＡＮＧＳＨ，ＤＩＮＧＸＣ，ｅｔａｌ．Ｒｉｎｇｓｈｅａｒｔｅｓｔｓｔｕｄｙｏｎｓｔｒｅｎｇｔｈｅｖｏｌｕｔｉｏｎｐｒｏｃｅｓｓｏｆｍｉｃｒｏｂｉａｌｒｅｉｎｆｏｒｃｅｄｃａｌｃａ⁃ｒｅｏｕｓｓａｎｄ［Ｊ］．ＪｏｕｒｎａｌｏｆＣｉｖｉｌａｎｄＥｎｖｉｒｏｎｍｅｎｔａｌＥｎｇｉｎｅｅｒｉｎｇ，２０２２，４４（４）：１０－１７．［１８］高玉琴，王建华，梁爱华．干湿循环过程对水泥改良土强度衰减机理的研究［Ｊ］．勘察科学技术，２００６（２）：１４－１７．ＤＯＩ：１０．３９６９／ｊ．ｉｓｓｎ．１００１－３９４６．２００６．０２．００４．ＧＡＯＹＱ，ＷＡＮＧＪＨ，ＬＩＡＮＧＡＨ．Ｔｅｓｔｓｔｕｄｙｏｎｉｎｆｌｕｅｎｃｅｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｃｈａｎｇｅｔｏｓｔｒｅｎｇｔｈｐｒｏｐｅｒｔｉｅｓｏｆｃｅｍｅｎｔｉｍｐｒｏｖｅｄｓｏｉｌ［Ｊ］．ＳｉｔｅＩｎｖｅｓｔｉｇａｔｉｏｎＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙ，２００６（２）：１４－１７．（责任编辑㊀田亚玲）６６１。
浓硫酸添加点对磷矿石反浮选作业的影响
浓硫酸添加点对磷矿石反浮选作业的影响杨稳权;罗廉明;彭杰【摘要】对海口中低品位磷矿石反浮选作业在不同的加药点添加浓硫酸和捕收剂YP-3,试验表明:在同一加药点同时添加浓硫酸和捕收剂YP-3,浮选指标较差,精矿产率低,且MgO含量高.对此类矿石的反浮选作业,需要在不同的加药点分别添加浓硫酸和捕收剂YP-3,以提高浮选过程的选择性,获得更理想的选矿指标.%It was studied that sulfaric acid and collector YP-3 was added in different dosing point with Haikon low grade phosphate rock reverse flotation operation.The results of the test indicated that: in the same dosing point and adding sulfuric acid and collector YP-3, flotation index is poor, pure mineral rate is low, and content of MgO is high.Such ore reverse flotation homework needs different dosing points respectively adding sulfuric acid and collector YP-3, in order to improve the flotation process selectivity and obtain more ideal dressing indexes.【期刊名称】《武汉工程大学学报》【年(卷),期】2011(033)003【总页数】3页(P79-80,86)【关键词】中低品位磷矿;浓硫酸;反浮选;云南省海口磷矿【作者】杨稳权;罗廉明;彭杰【作者单位】云南磷化集团研发中心,云南,昆明,650113;云南磷化集团研发中心,云南,昆明,650113;云南磷化集团研发中心,云南,昆明,650113【正文语种】中文【中图分类】TD970 引言云南海口磷矿浮选厂原设计时采用正反浮选工艺流程,且正—反浮选工艺流程采用同一种捕收剂,即在碱性条件下正浮选捕收磷矿物和在酸性条件下捕收碳酸盐矿物使用同一种捕收剂YP2(脂肪酸阴离子捕收剂).故在正浮选磷精矿进行反浮选前只设计了一台矿浆搅拌槽,用于添加浓硫酸(98%)作为磷矿物的抑制剂.由于浮选药剂的研发,提高了浮选药剂性能,用YP2-1(脂肪酸阴离子捕收剂)作为碱性条件下正浮选捕收磷矿物的捕收剂,用YP2-3(脂肪酸阴离子捕收剂)作为酸性条件下捕收碳酸盐矿物的捕收剂.这就造成了在同一台矿浆搅拌槽内同时需要添加反浮选抑制剂和捕收剂.本文就在反浮选工艺流程中同时添加硫酸和捕收剂进行试验研究,考察硫酸添加点对浮选过程的影响,及改进措施和方法.1 原矿性质试验矿样为海口矿区中低品位硅钙质磷矿岩,主要有用矿物为胶磷矿,主要脉石矿物为白云石、石英和玉髓.矿样多元素分析见表1所示.表1 生产矿样多元素分析结果Table 1 Production samples of ore more element analysis results %组分P2O5MgOSiO2CaOFe2O3Al2O3Na2OK2O 质量分数22.564.0819.2937.380.991.820.410.28从表1可以看出:生产矿样为硅钙质磷矿岩,其中m(CaO)/m(P2O5)=1.66,m(SiO2)/m(CaO)=0.52.对这类矿石在选矿过程中必须同时排除大部分碳酸盐和硅酸盐杂质后富集磷矿物,才能满足后续加工的要求.对此类矿石目前以正反浮选工艺流程生产较为成熟.即在碱性介质中,采用捕收剂富集磷矿物,硅酸盐矿物留在槽内产品作为尾矿被排除,泡沫产品为得到的正浮选磷精矿.在正浮选磷精矿中添加无机酸(通常用硫酸和磷酸)作为矿浆pH值调整剂和抑制剂,在弱酸性介质中用脂肪酸捕收剂浮出白云石,槽内产品为富集的磷矿物.2 试验内容2.1 相同加药搅拌时间试验试验采用对比法:一是采用反浮抑制剂(主要是硫酸)和捕收剂分开在不同的时间添加,二是将反浮抑制剂和捕收剂同时添加.不同药剂试验工艺流程及条件如图1所示,结果如表2所示.图1 浮选药剂制度不同试验工艺及条件流程图Fig.1 Flotation reagents system of different test process flow chart and conditions从表2可知:对反浮选作业,分别在不同时间添加浮选药剂比在同一个矿浆搅拌槽中同时添加抑制剂硫酸、磷酸和捕收剂YP2-3的浮选效果(精矿选别指标、选矿效率等)要好得多.表2 不同药剂制度试验结果Table 2 Different reagent regime test results加药方式产品名称产率γ/%品位β/%P2O5MgO回收率ε/%选矿效率E(ε-γ)/%β-γ排镁率/%不同时加药反浮精矿75.8931.650.7093.8617.976.0688.79反浮尾矿24.116.5017.466.14正浮精矿100.0025.594.74100.00同时加药反浮精矿68.5930.671.4582.4313.845.1578.61反浮尾矿31.4114.2811.6417.57原矿100.0025.524.65100.002.2 不同加药搅拌时间试验试验工艺流程如图2所示,结果如表3所示.从表3可知:随着浮选药剂搅拌时间的增加,精矿产率、回收率降低,精矿中P2O5品位、选矿效率升高,MgO品位降低,排MgO效率增加.图2 不同加药搅拌时间浮选试验工艺及条件流程图Fig.2 Different dosingwhisking time flotation test technology and conditions flow chart表3 不同加药搅拌时间试验结果Table 3 Different dosing whisking time test results搅拌时间/min产品名称产率γ/%品位β/%P2O5MgO回收率ε/%选矿效率E(ε-γ)/%β-γ排镁率/%0.5反浮精矿70.1830.761.4485.2815.105.4577.10反浮尾矿29.8212.5011.4114.72正浮精矿100.0025.314.41100.001.0反浮精矿68.6630.881.3383.6414.985.5379.57反浮尾矿31.3413.2311.3516.36 正浮精矿100.0025.354.47100.00 2.0反浮精矿68.2030.761.3082.3014.105.2779.51反浮尾矿31.8013.8011.4417.70 正浮精矿100.0025.374.52100.00 3.0反浮精矿65.7430.921.2880.3914.655.6782.10反浮尾矿34.2614.5710.5619.61 正浮精矿100.0025.324.46100.003 结果讨论浮选药剂的添加和调节是浮选过程中重要的工艺因素,对提高药效、改善浮选指标有重大影响[1].从表2和表3中可以看出,硫酸和YP-3的不同添加方式浮选指标相差较大,且增加或减少搅拌时间,也不能很好的改善浮指标.另外,浮选药剂添加地点的选择与该药剂的用途及溶解度有关[1].通常在反浮选脱除碳酸盐矿物的作业中,加入的硫酸因与碳酸盐矿物反应快,故反浮选酸的搅拌时间短,搅拌时间长短对浮选指标影响小.而对于捕收剂YP2-3则需要较长的搅拌时间,以利于充分和碳酸盐矿物接触,矿化充分而利于提高浮选过程的选择性.在同一矿浆搅拌桶中同时添加浓硫酸、磷酸和捕收剂YP-3,导致浓硫酸放热时将一部分捕收剂碳化,使得碳化了的那部分捕收剂失去了捕收能力;另外,硫酸、磷酸与一部分捕收剂(脂肪酸皂)发生了反应,生成脂肪酸,也使得这部分捕收剂选择性变差.硫酸与捕收剂YP-3(脂肪酸皂)生成脂肪酸的反应式为[2]:对海口中低品位磷矿石的反浮选作业,需分别在不同地点添加浓硫酸和脂肪酸捕收剂,以利更有效地提高浮选效率.现海口浮选厂已将反浮选浓硫酸、磷酸和捕收剂YP-3的加药点分开,即浓硫酸、磷酸加入到矿浆搅拌桶中,而捕收剂YP-3加入到浮选机给矿间箱中,浮选效果很好.参考文献:[1]胡为柏.浮选[M].北京:冶金工业出版社,1988:246.[2]朱玉霜.浮选药剂的化学原理[M].长沙:中南工业大学出版社,1996:56. Abstract: It was studied that sulfaric acid and collector YP-3 was added in different dosing point with Haikon low grade phosphate rock reverse flotation operation. The results of the test indicated that: in the same dosing point and adding sulfuric acid and collector YP-3, flotation index is poor, pure mineral rate is low, and content of MgO is high. Such ore reverse flotation homework needs different dosing points respectively adding sulfuric acid and collector YP-3, in order to improve the flotation process selectivity and obtain more ideal dressing indexes.Key words: low-grade phosphorus ore; sulfuric acid; reverseflotation;dressing indexes; Yunnan Haikou grade phosphorus。
除臭作用研究(翻译)
矿物掺料和生物技术对城市污泥的除臭作用研究（南昌大学建筑工程学院，江西南昌 330031）摘要：采用纳氏试剂分光光度法，定量研究了矿物掺料（硅藻土）和两种生物除臭剂（生物除臭剂Ⅰ和生物除臭剂Ⅱ）对城市污泥中氨含量的影响规律，以此分析其对城市污泥的除臭效果。
结果表明：不同掺量的硅藻土对城市污泥均有一定的除臭效果，硅藻土最优掺量为10%；两种生物除臭剂对城市污泥均有一定的除臭效果，但生物除臭剂Ⅱ优于生物除臭剂Ⅰ；复掺硅藻土和生物除臭剂Ⅱ比矿物掺料吸附或生物除臭单一方式的效果更好，其对城市污泥的除臭作用有叠加效应。
除臭效果最好且最经济合理的复合除臭剂配比为：5%硅藻土和0.3%生物除臭剂Ⅱ。
关键词：矿物掺料；生物技术；城市污泥；除臭中图分类号：文献标识码：文章编号：Study on Deodorization of Municipal Sludge by Means ofMineral Additives and BiotechnologyAbstract: Abstract: Using the spectrophotometric method, we analyze the influencing rule of mineral additives (diatomite) and two kinds of biological deodorant (biological deodorantⅠand biological deodorantⅡ) on the ammonia content in the municipal sludge quantificationally, and in order to analyze their deodorization of the municipal sludge thereby. The result indicates that the different contents of diatomite have the certain effect of deodorization on the municipal sludge, and the best content is 10%; Both of the biological deodorants have the certain effect of deodorization on the municipal sludge, and the biological deodorant Ⅱis better than the biological deodorantⅠ;the effect of the deodorization of the combination between diatomite and biological deodorant Ⅱis better than the single one works against the municipal sludge because of their superimposition effect. The proportion is 5% of diatomite and 0.3% of biotechnologyⅡconsidering the most effective and the most economic and reasonable factors.Key words: Mineral additives, Biotechnology, Municipal sludge, Deodorization——————————————————————胡明玉，女，1958年生，江西高安人，教授，博士江西省2008年科技支撑计划项目（2008AE01400）江西省2009年研究生创新基金资助项目江西省教育厅2010年度青年科学基金项目（GJJ10082）引言Introduction随着我国城市化速度加快，污水处理厂所产生的城市污泥量日益增加。
211274786_钙质泥岩粉尘对混烧体系中乏风瓦斯的氧化影响研究★
太原理工大学学报 JOURNAL OF TAIYUAN UNIVERSITY OF TECHNOLOGY
Vol.54 No.3 May 2023
引文格式:马艺桐,郝朝瑜,何文 浩,等.钙 质 泥 岩 粉 尘 对 混 烧 体 系 中 乏 风 瓦 斯 的 氧 化 影 响 研 究 [J].太 原 理 工 大 学 学 报, 2023,54(3):458-465. MA Yitong,HAOChaoyu,HE Wenhao,usmudstonedustonventilationgas inboilermixedcombustion[J].JournalofTaiyuan UniversityofTechnology,2023,54(3):458-465.
Copyright©博看网. All Rights Reserved.
第3期
马 艺 桐 ,等 :钙 质 泥 岩 粉 尘 对 混 烧 体 系 中 乏 风 瓦 斯 的 氧 化 影 响 研 究
459
inthemixedfiringsystem atthesametemperature,andthehigherthe metaloxidecontentof calcareousmudstonedust,thelowerthetemperatureatwhichtheconversionofspentairgasreaches its limit. According to the effect of dust on the gas conversion of the two coal blending systems,itcanbeseenthatalthoughthegasconversionrateofthelignitesystemisalwayshigher thanthatoftheanthracitesystem,thedusthasanegativeeffectontheconversionoftheVAMin thelignitesystemandapositiveeffectontheanthracitesystem,sotheeffectofdustontheanthraciteblendingsystemisbetterthanthatonthelignitesystem.Calcareousmudstonedustalso playstheroleofsulfurfixation,sothecalcareousmudstonedustinvolvedintheprocessofdischargingVAMfromtheminecanbeleftuntreatedandpassedintothecoal-firedboilertogether with VAM.
石英砂岩碱骨料反应抑制措施的试验研究
石英砂岩碱骨料反应抑制措施的试验研究李鹏翔;王黎;彭尚仕【摘要】The content of SiO2 in Quartz sandstone is high, and is usually in the form of silica cementing, which has the poten-tial of alkali-aggregate reaction. In order to study the danger of alkali-aggregate reaction of quartz sandstone aggregate adopted by a hydropower project and findthe countermeasures, we conducted test on the inhibiting effectiveness of alkali-aggregate reac-tion of the quartz sandstone using accelerated mortar bar method, concrete prism method and mortar bar length method. The re-sults showed that by taking prevention measures such as adopting low-alkali cement(alkali content less than 0. 60%), adding to least 30% offly ash and controlling the total alkali content of concrete strictly, thealkali-aggregate reaction of the quartz sand-stone can be effectively inhibited and the durability of the concrete can be guaranteed.%石英砂岩中二氧化硅含量高，一般为硅质胶结，具有潜在危害性反应的碱活性。
稀土精矿负载Fe_(2)O_(3)矿物催化材料的NH_(3)-SCR脱硝性能研究
第21卷第3期2021年3月过程工程学报The Chinese Journal of Process EngineeringVol.2l No.3Mar. 2021烹严一---SKA"參环境与能源'fDOI: 10.12034/j.issn. 1009-606X.219383Study on NH3-SCR denitration performance of rare earth concentratesupported Fe2()3 mineral catalytic materialZhaolei MENG'7, BaoweiLI 1, Jinyan FU 1-2, Chao ZHU 12, Wenfei WU 12*1. Key Laboratory of Efficient and Clean Combustion, Inner Mongolia, Baotou, Inner Mongolia 014010, China2. School of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014010, ChinaAbstract: In this work, a series of mineral catalytic materials were obtained by using Bayan Obo rare earth concentrate rich in Ce oxide as the catalystmaterial, impregnated with ferric nitrate solutionand microwave roasted. XRD, SEM, EDS, XPS andother methods were used to characterize the mineral phase structure and surface morphology of thecatalyst, and to determine its denitration activity.The results showed that the rare earth concentrateimpregnated in 0.5 mol/L ferric nitrate solution (Catalyst 3) had the best structural characteristics,• 严 ••••Catalyst 1 Catalyst 2 Catalyst 3 Catalyst 4SEM image of mineral catalytic materialsn 2 h 2oee + yXRD patterns of mineral catalytic materials• .......................• *•*■♦*•“ .»•••.• ・.・Fe ：O> ・CaF ：• % * -**-* • •• •・•aulysl 4 alalyst 3. * »l e< e.O. •< ■i —9 一aul>sl 2Jthe surface was rough and porous, and obvious and deep cracks appeared, which was conducive to the diffusion of gason the surface of the material. Most Fe2()3 was embedded in the rare earth concentrate in a highly dispersed oramorphous form. The content of Ce 3+ and Fe 2+ were increased after immersion in ferric nitrate solution and microwaveroasting. Active components Ce coexisted in the form of Ce 3+ and Ce 4+, Fe coexisted in the form of Fe 2+ and Fe 3+. The conversion of adsorbed oxygen and lattice oxygen increased significantly, and there were more oxygen vacancies foroxygen transfe 匚 The change in the valence of Fe ions and Ce ions indicated that Fe and Ce had a combined effect togenerate a small amount of Fe and Ce composite oxides. With the increase of medium and strong acid sites on the surface of Catalyst 3, the ability of the surface to adsorb NH3 increased, and its denitration effect was the best. When the microwave roasting temperature was 350°C, the denitration rate can reach 80.6%.Key words: rare earth concentrate; catalytic denitrification; mineral catalysis; carrier收稿：2019-12-23,修回：2020-05-18,网络发表：2020-06-08, Received: 2019-12-23, Revised: 2020-05-1 & Published online: 202—8基金项目：国家自然科学基金资助项目（编号：51866013）；内蒙古自治区自然科学基金-重大项目（编号：2019ZDI3）作者简介：孟昭磊（1989-）,男，吉林省四平市人，硕士研究生，研究方向为稀土矿物材料催化剂制备，E-mail: ****************：武文斐，通讯联系人，E-mail: ************.364过程工程学报第21卷稀土精矿负载Fe2O3矿物催化材料的NHs-SCR脱硝性能研究孟昭磊毗，李保卫1,付金艳12,朱超1，2,武文斐12*I.内蒙古自治区高效洁净燃烧重点实验室，内蒙古包头0140102.内蒙古科技大学能源与环境学院，内蒙古包头014010摘要：以白云鄂博富含Ce氧化物的稀土精矿为催化材料的载体，采用硝酸铁溶液浸渍、微波焙烧获得一系列矿物催化材料。
盐碱地土壤改良试验研究
盐碱地土壤改良试验研究——以粉煤灰和煤矸石改良盐碱土为例赵旭，彭培好,李景吉（成都理工大学地球科学学院四川成都610059）摘要：本文采用盆栽试验, 重点探讨了粉煤灰和煤矸石改良盐碱土对柽柳生长的影响。
结果表明：施加15 %粉煤灰+15 %淤泥改良盐碱土效果明显好于10 %粉煤灰+10 %煤矸石+10 %淤泥的效果，好于20 %粉煤灰的改良效果。
基质中加入粉煤灰，对提高柽柳发芽率、缩短枝条发芽时间和提高萌发枝条成活率均具有促进作用。
施加粉煤灰改良盐碱土的优劣比例顺序为：粉煤灰15 %>20 %>10 %。
本试验达到了试验初衷要求和期望值，对于已获取的数据的分析是科学的、可行的，具有借鉴意义。
关键词：粉煤灰；煤矸石；柽柳；盐碱土中图分类号：S714 文献标识码：A干旱区土壤盐碱化是土地退化的主要问题，并威胁着绿洲农业的可持续发展[1]。
西北地区位于我国干旱、半干旱区, 年均降水量不足200 mm，干燥度大于4，多风沙，昼夜温差大，自然环境十分恶劣[2]，形成了大量的盐碱地面积。
造成该区土壤结构板结，植物类型单调，绿化面积大量减少，降低了生态系统的功能，造成了当地严重的生态问题。
如何对西北地区盐碱地进行治理，已经成为国家关注的重要问题之一及多年来科学研究的热点问题。
粉煤灰是目前世界上影响环境的主要废弃物之一[3]。
粉煤灰的理化性质测定表明：施加粉煤灰可降低土壤容重和pH值，减少土壤中碱性物质含量[4-6,13]，碱性粉煤灰和中性的污泥配合能很好的改良酸性土。
而煤矸石中含有大量有机物，是携带固氮、解磷、解钾等微生物的理想基质，土壤中施加适量的煤矸石，可以改善土壤容重、孔隙度等土壤物理性状[7-8,14]。
国内外对盐碱地及其改良的研究很多，但对于粉煤灰和煤矸石对盐碱地的研究仍存在一些问题，给盐碱土改良方案带来不确定因素[3-4,9]。
基于此，作者针对西北地区的盐碱地改良开展了实验性性研究。
1 材料与方法1.1材料试验采用的土壤为宁夏银北地区中盐渍化土壤；所用的植物试材为柽柳（Tamarix chinensis.）二年生根桩苗，采自于河北生物研究所的苗圃地；添加的改良剂为：粉煤灰（a）、煤矸石(b)、淤泥（c），其中粉煤灰、煤矸石采集于四川省成都市成华区火电厂，淤泥采集于成华区火电厂周围的泥塘，距火电厂约0.5 km。
湖南省长沙市雅礼书院中学2025届高三英语第一学期期末学业质量监测试题含解析
湖南省长沙市雅礼书院中学2025届高三英语第一学期期末学业质量监测试题注意事项1．考生要认真填写考场号和座位序号。
2．试题所有答案必须填涂或书写在答题卡上，在试卷上作答无效。
第一部分必须用2B 铅笔作答；第二部分必须用黑色字迹的签字笔作答。
3．考试结束后，考生须将试卷和答题卡放在桌面上，待监考员收回。
第一部分（共20小题，每小题1.5分，满分30分）1．The disaster-stricken village was inaccessible ___________ by helicopter, and the storm added to the rescuers’ difficulty.A．instead of B．other than C．rather than D．regardless of2．Eventually, she has recognized ____, whatever happens and however bad ____ seems today, life still goes on and everything will be better tomorrow．A．that; it B．it; that C．it; what D．that; what3．I live in a town ______ runs a small and winding river.A．through which B．which C．in which D．where4．---Tom has failed again in the math exam. I am really let down.---______ He has already done his best.A．Don’t push him. B．No kidding.C．He should be to blame. D．No wonder.5．My friend warned me ______ going to the East Coast because it was crowded with tourists.A．by B．against C．on D．for6．I'm sorry you ______ so long, but it' ll still be some time before Jim gets back．A．wait B．waited C．had waited D．have been waiting7．When was _____ you last met Jennifer? I haven’t seen her for ages.A．it that B．it C．it what D．what 8．___________the effect of culture shock, he is trying to read a lot about it before going to France for further study.A．To reduce B．ReducedC．Reducing D．Having reduced9．Have you read the book Life and Death Are Wearing Me Out by Mo Yan, _____ that won him the 2012 Nobel Prize in Literature?A．the one B．one C．those D．ones10．Molly finally agreed, _____ reluctantly, to go and see a doctor.A．afterwards B．almostC．otherwise D．somewhat11．It was in that small house ________ was built with stones by his father ________ he spent his childhood.A．that; where B．which; thatC．which; which D．that; which12．—How about his design?—Well, to tell the truth, it is ______ but satisfactory. So you’ll have to try your best to better it.A．something B．anythingC．everything D．nothing13．—I think the paper is taking you a long time to write.—I ______ on it for almost a month now.A．worked B．was workingC．am working D．have been working14．Have you got these jeans in ________ larger size? This pair is a bit too small around ________ waist.A．a; the B．/; theC．the; / D．a; a15．—Do you think he is the only person for the job?—I’m not quite sure but he’ll prove_______ to the task.A．equal B．essentialC．special D．superior16．— David is a green hand at such things.— But I believe he is quite ________ to the task.A．relevant B．accessibleC．equal D．unique17．So difficult____it to work out the problem that I decided to ask Tom for advice. A．I did find B．didI findC．I have found D．have I found18．They went to the street to ________ to the whole city to help the poor boy. A．apply B．appealC．add D．reply19．The only problem was ______ we kept getting lost! But people in Tianjin are very friendly and helpful.A．why B．whetherC．that D．how20．She was such a proud person that she would die she would admit she was wrong.A．since B．whenC．unless D．before第二部分阅读理解（满分40分）阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
scientist studying the effects of
Scientists studying the effects of various phenomena play a crucial role in expanding our understanding of the natural world, human behavior, and the complex interplay between different variables. This process involves systematic investigation, data collection, analysis, and interpretation to draw meaningful conclusions. Let's explore the broader concept of scientists studying the effects of different factors and delve into the methodologies, significance, and challenges associated with such studies.### **Introduction:**Scientists engaging in the study of effects often aim to uncover causal relationships, identify patterns, or understand the impact of certain factors on a given system. This exploration encompasses a wide range of disciplines, including physics, chemistry, biology, psychology, environmental science, and social sciences. The effects being studied can be diverse, ranging from the microscopic level of particles to the macroscopic level of ecosystems or human societies.### **Methodologies in Studying Effects:**1. **Experimental Design:**- **Controlled Experiments:** Scientists often use controlled experiments to isolate specific variables and observe their effects systematically. This involves manipulating one variable while keeping others constant.2. **Observational Studies:**-**Longitudinal Studies:** Researchers track subjects over an extended period to observe changes and identify potential causative factors.- **Cross-Sectional Studies:** Examining a diverse group at a single point in time to uncover correlations and associations.3. **Field Studies:**-**Ecological Studies:** Scientists study effects within natural environments, observing interactions between organisms and their surroundings.-**Social Science Field Studies:** Researchers may conduct surveys or interviews to understand the effects of social, economic, or cultural factors on individuals or communities.4. **Computer Modeling:**- **Simulation Studies:** Scientists use computer models to simulate real-world scenarios, allowing them to predict and analyze potential effects without real-world experimentation.### **Significance of Studying Effects:**1. **Scientific Advancement:**- **New Discoveries:** Research on the effects of various factors often leads to the discovery of new phenomena, principles, or relationships.-**Advancement of Knowledge:** Building on existing knowledge, scientists contribute to the continuous advancement of their respective fields.2. **Problem Solving:**- **Environmental Solutions:** Studying the effects of human activities on the environment aids in developing strategies for sustainable resource use and conservation.- **Medical Breakthroughs:** Understanding the effects of drugs, diseases, and lifestyle on health contributes to medical advancements and improved healthcare.3. **Policy Formulation:**-**Informed Decision-Making:** Governments and organizations use scientific studies to formulate policies addressing societal issues, such as public health, education, and environmental protection.-**Risk Assessment:** Studying the effects of potential hazards helps in assessing and mitigating risks to human health and safety.4. **Technological Innovation:**- **Materials Science:** Studying the effects of different materials on each other contributes to the development of new materials with enhanced properties.-**Engineering Advancements:** Understanding the effects of forces, temperature, and other factors on structures and systems informs engineering practices and innovations.### **Challenges in Studying Effects:**1. **Complexity of Systems:**-**Interconnected Variables:** Natural systems are often complex, with numerous interconnected variables. Isolating the effect of one variable while keeping others constant can be challenging.2. **Ethical Considerations:**- **Human Subjects:** In social and medical studies, ethical considerations, such as informed consent and the potential for harm, must be carefully addressed.-**Environmental Impact:** Researchers studying ecological effects must consider the potential impact of their studies on the environment.3. **Resource Limitations:**-**Financial Constraints:** Conducting comprehensive studies requires financial resources for equipment, personnel, and data analysis.- **Time Constraints:** Longitudinal studies, in particular, can be time-consuming, requiring sustained funding and commitment.4. **Data Interpretation:**-**Statistical Challenges:** Interpreting data and drawing meaningful conclusions require statistical expertise to avoid misinterpretation or bias.- **Correlation vs. Causation:** Distinguishing between correlation and causation is critical to avoid drawing incorrect causal relationships.### **Case Study: Studying the Effects of Climate Change:**Consider a case study where scientists are studying the effects of climate change:1. **Methodology:**- **Observational Studies:** Scientists analyze long-term climate data, including temperature records, sea-level measurements, and ice core samples.-**Computer Modeling:** Climate scientists use sophisticated models to simulate future climate scenarios based on different emission scenarios.2. **Significance:**- **Policy Impact:** Findings contribute to global efforts to mitigate climate change, shaping international agreements and policy decisions.-**Environmental Awareness:** Studying the effects raises public awareness of climate change impacts, fostering environmentally conscious behaviors.3. **Challenges:**- **Data Uncertainty:** Climate systems are intricate, and uncertainties in data interpretation can pose challenges in predicting future scenarios.- **Global Collaboration:** Studying a phenomenon as pervasive as climate change requires international collaboration and coordination.### **Conclusion:**In conclusion, scientists studying the effects of various factors contribute significantly to human knowledge, technological innovation, and policy formulation across diverse disciplines. The methodologies employed, the significance of their findings, and the challenges they face vary depending on the field of study. Despite challenges, the pursuit of understanding the effects of different variables remains integral to scientific progress and addressing global challenges.。
Compressive Strength and Rapid Chloride Permeability of
Compressive Strength and Rapid Chloride Permeability ofConcretes with Ground Fly Ash and SlagOzkan Sengul 1and Mehmet Ali Tasdemir 2Abstract:Concretes with binary and ternary blends of portland cement,finely ground fly ash and finely ground granulated blast furnace slag were produced to investigate their effects on compressive strength and rapid chloride permeability.Portland cement was partially replaced by finely ground fly ash ͑Blaine specific surface:604m 2/kg ͒and finely ground granulated blast furnace slag ͑Blaine specific surface:600m 2/kg ͒.Two series of concrete with water/binder ratios of 0.60and 0.38were produced and for both water/binder ratios,portland cement was replaced by:͑i ͒50%fly ash;͑ii ͒50%blast furnace slag;and ͑iii ͒25%fly ash+25%blast furnace slag.At the high water/binder ratio,compressive strengths of the concretes with the pozzolans are lower compared to that of the portland cement concrete.At the low water/binder ratio,however,these strength reductions are less compared to the high water/binder ratio and compressive strength of the concrete produced with 50%slag was even higher than the portland cement concrete.The test results indicate the ground fly ash and ground granulated blast furnace slag greatly reduce the rapid chloride permeability of concrete.It was concluded that to reduce the chloride permeability of concrete,inclusion of pozzolans are more effective than decreasing the water/cement ratio.DOI:10.1061/͑ASCE ͒0899-1561͑2009͒21:9͑494͒CE Database subject headings:Fly ash;Slag;Compressive strength;Chlorides;Optimization;Concrete;Portland cements;Permeability .IntroductionCement production is an energy intensive process which also has an important effect on the environment.Producing one ton of portland cement releases about one ton of CO 2green house gas into atmosphere and as a result of this production 1.6billion tons of CO 2is released every year which is estimated at about 7%of the CO 2production worldwide ͑Mehta 2001;Malhotra 1999͒.The pressure of ecological constraints and environmental regulations are bound to increase in the coming years which will lead to greater use of supplementary cementitious materials such as fly ash or ground granulated blast furnace slag ͑GGBS ͒͑Aitcin 2000͒.There are two major reasons to use these by-products in concrete:͑1͒decreasing cement consumption by replacing part of cement with these pozzolanic materials and ͑2͒improving fresh and hardened concrete properties.In recent years,the reduction of water/cement ratio by using superplasticizers and usage of ul-trafine mineral admixtures lead to high performance concrete.Be-side the advantages,pozzolanic materials have certain drawbacks.To overcome some of the disadvantages and to be able to use the pozzolan in higher amounts,quality of the pozzolan can be im-proved.Chemical composition,particle-size distribution,fineness,andpozzolanic activity,and curing conditions of concrete are impor-tant factors affecting the properties of concretes with pozzolanic materials ͑ACI Committee 2321996;ACI Committee 2331995;ACI Committee 2341996͒.In recent years,it has been shown that the filler effect of mineral admixtures may be as important as their pozzolanic effects;according to some researchers,however,the filler effect can be more important than the pozzolanic effect ͑Goldman and Bentur 1993;Isaia et al.2003͒.Particle-size dis-tribution clearly plays a very important role in the rate of chemi-cal reactivity and in the water demand.Pozzolanic reaction takes place on the surface of the particles and increasing surface area has an important effect on pozzolanic activity.Thus,the fineness of the pozzolan is very important for the improvement of cement paste-aggregate interfacial zone,which is the weakest link in con-crete.In a previous investigation done by the research group of this study ͑Demir et al.2002͒,a coarse F type fly ash with a Blaine surface area ͑BSA ͒of 222m 2/kg was ground to four different finenesses such as 337,450,538,and 604m 2/kg.The purpose of the work mentioned was to study the effects of fly ash grinding on physical properties and strength development of concrete.It was concluded that as the fineness of fly ash increases,the compres-sive strength of concrete increases significantly.The particle size is an important factor also for the pozzolanic activity of the granulated blast furnace slag.Similar to the fly ash,the strength of slag concretes also increases with slag fineness ͑Tasdemir et al.1997;Niu et al.2002͒.Besides increasing the fineness,another solution to overcome the disadvantages of using high amounts of pozzolan,is to use ternary or quaternary blends of portland cement and pozzolans.By using different pozzolans together,some of the shortcomings can be compensated and more environmentally friendly concretes with specific properties can be obtained.The main objective of the work presented herein is to investi-gate the effects of ground fly ash and blast furnace slag on com-1Assistant Professor Doctor,Faculty of Civil Engineering,Istanbul Technical Univ.,34469Maslak,Istanbul,Turkey ͑corresponding author ͒.E-mail:sengulozk@.tr 2Professor Doctor,Faculty of Civil Engineering,Istanbul Technical Univ.,34469Maslak,Istanbul,Turkey.Note.This manuscript was submitted on December 17,2007;ap-proved on March 26,2009;published online on August 14,2009.Dis-cussion period open until February 1,2010;separate discussions must be submitted for individual papers.This paper is part of the Journal of Materials in Civil Engineering ,V ol.21,No.9,September 1,2009.©ASCE,ISSN 0899-1561/2009/9-494–501/$25.00.D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S o u t h e a s t U n i v e r s i t y o n 12/12/13. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .pressive strength and chloride permeability of concrete at high replacement percentages.In this work,a finely ground low-lime fly ash ͑Blaine fineness of 604m 2/kg ͒and finely ground blast furnace slag ͑Blaine fineness of 600m 2/kg ͒were used in normal and high strength concretes to partially replace ordinary portland cement with a replacement amount of 50%.Concretes with ter-nary blends were also produced containing 25%fly ash and 25%pressive strength and rapid chloride ion permeability of the concretes were obtained at 28and 90days.To attain a durable concrete mixture low chloride permeability should be obtained.Achieving high compressive strength in a concrete structure is important for structural safety.The cost of concrete is also impor-tant from the applicability point of view.For this purpose a mul-tiobjective optimization method was performed in which the compressive strength was maximized but the rapid chloride per-meability and the cost were minimized.The responses in the op-timization were considered to be of equal importance.Experimental Details MaterialsSame ordinary portland cement ͑PC 42.5͒,finely ground fly ash,and finely ground blast furnace slag were used in the concretes.The 7-and 28-day compressive strengths of the standard RILEM-Cembureau cement mortars were 45.8and 57.3MPa,respec-tively.The fly ash used in this study was brought from Catalagzi power plant,which is located in the northwest coast region of Black Sea in Turkey.The blast furnace slag was obtained from Karabük production plant also located in the same region.Chemi-cal compositions of ordinary portland cement ͑OPC ͒,fly ash and slag are shown in Table 1.The fly ash and blast furnace slag were ground in a laboratory ball mill.The original Blaine fineness of the fly ash was 222m 2/kg and was increased to 604m 2/kg by grinding.The ground blast furnace slag used in this study also had Blaine fine-ness of 600m 2/kg.Some physical properties of the fly ash and slag are shown in Table 2.The average particle size of the fly ash used was relatively fine and characterized by a high density.In this study,the ground fly ash indicated in Table 2was used.Physical properties of the fly ash such as density and fineness change as it is ground.The physical changes due to grinding are:͑1͒the fineness of fly ash increases;͑2͒there is a remarkable increase in density by reduc-ing the porosity of the fly ash particles;and ͑3͒the spherical fly ash particles transform into the mostly irregular shapes;somesmall fly ash particles keep their original shapes.These conclu-sions were also reported in other works ͑Demir et al.2002;Sen-gul et al.2005͒.Effects of grinding on the fly ash particles are shown in Fig.1.Fig.2shows that the average particle size de-creases by grinding of the coarse fly ash.Table 1.Chemical Compositions of Portland Cement,Fly Ash,and Slag Oxide composition ͑%͒OPC ͑PC 42.5͒Fly ash Blast furnace slag SiO 220.060.240.5Fe 2O 3 3.6 6.7 1.2Al 2O 3 5.121.810.3CaO 63.2 2.532.2MgO 1.1 1.611.3SO 3 2.80.5 1.3K 2O 0.8 4.9 1.1Na 2O 0.30.50.35Cl -0.030.0060.0105Loss on ignition2.80.31.9Table 2.Some Physical Properties of Fly Ash and Blast Furnace SlagPropertyFly ashBlast furnace slag Before grinding After grinding Density2.00 2.51 2.86BSA,m 2/kg222604600Retained on 200m sieve,%12.00.00.0Retained on 90m sieve,%33.00.70.0Retained on 45m sieve,%50.03.70.2(a)Original fly ash particles (before grinding)(Blaine surface area:222m 2/kg)(b)Ground fly ash particles (Blaine surface area:450m 2/kg)(c)Ground fly ash particles (Blaine surface area:604m 2/kg)Fig.1.SEM images of ground fly ash particles:͑a ͒original particles;͑b ͒ground fly ash,BSA:450m 2/kg;and ͑c ͒ground fly ash,BSA:604m 2/kgD o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S o u t h e a s t U n i v e r s i t y o n 12/12/13. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .Pozzolanic ActivityPozzolanic activity is one of the critical properties of the mineral admixtures and there are different methods for the determination of the pozzolanic activity of these materials.For the fly ash used in this study,the pozzolanic activity test with lime was done according to ASTM C 311–85͑ASTM 1985a ͒.The test results obtained are given in Table 3together with ASTM C 618–85limits ͑ASTM 1985b ͒.An increase in the fineness of the fly ash leads to a substantial increase in its activity index at 7days.As seen in Table 3,increasing the BSA from 222to 604m 2/kg has resulted in an increase of approximately 80%in corresponding compressive strengths at 7days.Pozzolanic activity of the slag was obtained according to ASTM C989-06͑ASTM 2006͒which is based on the comparison of the compressive strengths of reference cement mortars and those of mortars produced with portland cement-slag blend.ASTM C989-06͑ASTM 2006͒mentions three grades for slag:Grade 80,Grade 100,Grade 120.The requirements for these grades and the results obtained for the slag used in this study are shown in Table 4.Based on these test results,the ground slag used can be classified as Grade 100.However,it should be noted that the results obtained are very close to the limits for Grade 120.Mixture ProportioningTwo series of concretes were produced with water/binder ratios of 0.60and 0.38.For both water/binder ratios;portland cement was replaced by:͑i ͒50%finely ground fly ash;͑ii ͒50%finely GGBS;and ͑iii ͒25%finely ground fly ash+25%finely GGBS.In all concretes,partial replacement of cement by fly ash and slag wason one to one weight basis.Portland cement concretes were also produced for each water/cement ratio.Basalt type coarse aggre-gate was used in all concretes to obtain better concrete strengths ͑Sengul et al.2002͒.The aggregate had a low porosity and high specific gravity.To obtain a better aggregate-cement paste inter-face,the aggregates were washed and used in saturated surface dry state.The aggregate grading,water-binder ratio,and the maximum particle size of aggregate were kept constant in all concretes.The grading curve of concrete aggregate was chosen between ISO A16-B16and closer to B16.Natural sand,crushed basalt sand,and crushed basalt No.I was used in the concretes.A superplasticizer was used in low water/binder concretes to main-tain approximately the same slump.The concrete mixtures were designated as follows:50S-60,50F-60,25FS-60,50S-38,50F-38,and 25FS-38.The first two digits show the partial replacement amount of cement by the fly ash or slag.The letters after the digits represent the binder type,where S shows the blast furnace slag and F indicates the fly ash.The last two digits indicate the water/binder ratio as %.For ex-ample 25FS-38represents the concrete with a water/binder ratio of 0.38and containing 25%fly ash+25%blast furnace slag.On the other hand,the mixtures 100PC-60and 100PC-38show port-land cement concretes with water/cement ratios of 0.60and 0.38,respectively.All mixtures were prepared in a laboratory mixer with vertical rotation axis by forced mixing.Details of the mixtures are shown in Table 5.All the specimens were demolded after 24h and stored in a water tank saturated with lime at 20°C until the testing day.Test ProcedureThree 150mm cubes were used for the standard compressive strengths of concretes.The rapid chloride ion permeability of the concretes was obtained according to ASTM C 1202–05͑ASTM 2005͒;three concrete disc specimens of 100mm in diameter and 50-mm thick were used for the test.The compressive strength and the rapid chloride permeability of concretes obtained at 28-and 90-day old specimens are given in Table 6.Results and DiscussionCompressive Strengths of ConcretesCompressive strengths of the concretes are illustrated in Figs.3and 4.As seen in Fig.3,for the water/binder ratio of 0.60,the compressive strength of the concrete with 50%slag replacement is slightly lower than the portland cement concrete both for 28and 90days.The compressive strength of the concrete with 50%fly ash replacement,however,is significantly low.For the 0.60water/binder ratio,at 28days the strength of the fly ash concrete is 59%of the portland cement concrete.At 90days,however,this ratio is 75%,which shows the significant strength development rate of the fly ash concrete between 28and 90days.Despite this substantial strength reduction compared to portland cement con-crete,at 0.60water/binder ratio and 28-day age,the compressive strength of the concrete with 50%fly ash is still over 34MPa and this concrete can be classified as a structural concrete.The pozzolanic reaction of fly ash in concrete depends on the break-down and dissolution of the glass phase which occurs when the pH of pore solution is higher than 13͑Fraay et al.1989͒.The pozzolanic reaction takes place between the fly ash and the CHParticle Diameter,µmC u m u l a t i v e p e r c e n t a g e501002575Fig.2.Particle-size distributions of fly ashes before and after grind-ingTable 3.Results of Pozzolanic Activity Index Test on the Fly AshCompressive strength at 7days,MPaFly ashBefore grinding,BSA:222m 2/kgAfter grinding,BSA:604m 2/kgExperiment7.914.2Class F in ASTM C618-85,min5.55.5Table 4.Results of the Slag Activity Index Test Slag activity index ASTM C989-06,minBlast furnace slag used in the studyGrade 80Grade 100Grade 1207-day index —75959128-day index7595115114D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S o u t h e a s t U n i v e r s i t y o n 12/12/13. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .produced from the hydration of portland cement.This pozzolanic reaction is a slow process and is responsible for the low early strength of the high volume fly ash concrete.At the 0.60water/binder ratio,the compressive strength in-crease between 28and 90days is about 27%for the fly ash concrete,3%for the portland cement concrete,8%for the slag concrete,and 19%for the concrete with the ternary binder.This important strength increase of fly ash concrete indicates that the pozzolanic reaction of the fly ash continues at a higher rate for a longer period.The pozzolanic reaction of the blast furnace slag is more rapid when compared to that of the fly ash ͑Bijen 1996a ͒.For the dis-solution of the glass phase of blast furnace slag,pore water pH of about 12is enough and this alkalinity level occurs in a short period after mixing the slag-portland cement blend with water.This more rapid reaction is one of the factors causing a higher early strength of slag concretes.As shown in Fig.3,for the water/binder ratio of 0.60,the compressive strength of the concrete with ternary blend binder is between those of the slag concrete and fly ash concrete.The ter-nary binder containing 25%fly ash and 25%slag also has a significant strength increase between 28and 90days.The compressive strength of the concretes at 0.38water/binder ratios are shown in Fig.4.As seen in the figure,the strength of the slag concrete is higher than that of the portland cement con-crete at 28days and almost equal at 90days.The compressive strength of the concrete with 50%fly ash is 72.8MPa at 28days and 78.2MPa at 90days and this high volume fly ash concrete can be classified as a high strength concrete.For the water/binder ratio of 0.38concretes,the strength of the fly ash concrete is about 85%of the portland cement at both ages.For normal strength concretes,however,this strength ratio is 59%at 28days and 75%at 90days.When the results for the 0.38and 0.60water/binder ratios are compared,it can be concluded that the fly ash is much more effective at the low water/binder ratio for enhancing the strength of concrete.The better performance of fly ash at lower water/binder ratios was also reported in other studies ͑Demir et al.2002;Poon et al.2000;Lam et al.2000;McCarthy and Dhir 1999͒.Similar conclusions can also be drawn for the slag concrete and the concrete with the ternary binder.For the high water/binder ratio,the ratio of the compressive strength of slag concrete to that of portland cement is 92%at 28days and 96%at 90days,but this strength ratio increases to 105%at 28days and 99%at 90days for 0.38water/binder ratio.Mineral admixtures have two effects in concrete:pozzolanic effect and filler effect.A finer pore size distribution and less cap-illary pores can be obtained by using fine mineral admixtures in concrete.Fine pozzolanic materials also have an important effect on the aggregate-cement paste interface which is the weakest link in concrete and the thickness of this transition zone can be re-duced by using pozzolans ͑Bijen 1996b ͒.Better particle packing due to finer materials and the pozzolanic reaction may be the reasons for this enhancement.By the densification of the aggregate-cement paste transition zone,concrete becomes more homogeneous and higher strengths can be obtained.This im-provement may be more effective at lower water/binder ratios which can cause a better performance of the pozzolan.For the low water/binder ratio concretes,superplasticizers areTable 5.Mix Proportions and Some Properties of the Fresh Concretes Mix code100PC-6050S-6050F-6025FS-60100PC-3850S-3850F-3825FS-38Cement,kg /m 3348175176176450222221222Slag,kg /m 3017508802220111Fly ash,kg /m 3001768800221111Water,kg /m 3209210211211167168167168Water/binder0.600.600.600.600.380.380.380.38Superplasticizer,kg /m 30000 4.4 4.5 3.4 4.7Natural sand,kg /m 3503503497502500499487493Crushed basalt sand,kg /m 3380380375379377377368372Crushed basalt I,kg /m 3951952940951946945921933Slump ͑mm ͒9013014014080150110160Unit weight,kg /m 32,3892,3942,3752,3962,4362,4382,3892,415Air ͑%͒2.21.61.10.93.32.73.12.8Table 6.Mechanical Properties,Chloride Permeability,and Relative Cost of ConcretesWater/binder Mixture code Cube compressive strength of concrete͑MPa ͒ASTM C1202chloride ion penetration test͑Coulomb ͒Relative costs of concretes28days 90days 28days 90days 0.60100PC-6055.757.56,8135,500348.050S-6051.355.3703372288.850F-6034.243.3926161264.025FS-6042.951.2660376277.20.38100PC-3886.192.21,8771,780450.050S-3889.991.5395206366.350F-3872.878.2531144331.525FS-3883.186.6387217349.7D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S o u t h e a s t U n i v e r s i t y o n 12/12/13. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .used to obtain enough workability.These chemical admixtures causes better dispersion of cement particles and higher early com-pressive strengths can be achieved due to the greater hydration rate in a well dispersed system ͑Mehta and Monterio 1993͒.The superplasticizer used in the 0.38water/binder ratio concretes may have helped for a better dispersion of the pozzolans which may have caused a less strength decrease when compared to the 0.60water/binder ratio concretes.The enhanced hydration in a well dispersed binder system also depends on the size of the mineral admixture.The particle sizes of the fly ash and slag used in this study are relatively fine and have Blaine finenesses of 600m 2/kg.The fine particle size of the pozzolans may have contributed to the better performance of concretes at the low water/binder ratio.Resistance to Chloride Ion PenetrationThe ASTM C 1202-05͑ASTM 2005͒rapid chloride ion penetra-tion test ͑RCPT ͒results of the concretes are given in Figs.5and 6.This test is based on the electrical conductivity of concrete.The concrete sample is subjected to a potential difference of 60V and the total charge passing through sample at the end of 6h is mea-sured and expressed in terms of Coulombs.A reduction in this total charge value indicates the better resistance to chloride ion penetration and lower permeability.As seen in the figures,for both water/binder ratios,pozzolan replacements caused great re-ductions in the rapid chloride permeability of the concretes.As shown in Fig.5,for the 0.60water/binder ratio and age of 28days,replacing 50%of portland cement by the fine slag caused a decrease of about 90%in the rapid chloride permeability of the concrete.Similarly,the reductions for the fly ash concrete and the concrete with the ternary binder are more than 86and 90%,re-spectively.For this water/binder ratio and 28-day age,the con-crete with the ternary binder has the lowest RCPT value.As seen in the figures,the rapid chloride ion permeability de-creases with age.For the water/binder ratio of 0.60,the total charge passing through the portland cement concrete decreases about 20%between 28and 90days.This decrease,however,is more substantial for the concretes containing high volume of poz-zolans.For the 0.60water/binder ratio,the reduction of the chlo-ride permeability between 28and 90days is about 47%for the slag concrete,83%for the fly ash concrete,and 43%for the concrete with the ternary binder.At 90-day age and 0.60water/binder ratio,the concrete with slag and with the ternary blend have RCPT values of about 7%of the portland cement concrete and with a value of 161Coulombs the fly ash concrete has the lowest value which is less than 3%of the normal concrete.If Figs.5and 6are compared,the effect of water/binder ratio on the rapid chloride permeability can be seen.For both 28and 90days,decreasing water/binder ratio from 0.60to 0.38caused a reduction of the RCPT value of about 70%for the portland ce-ment,44%for the slag concrete,and 42%for the concrete with the ternary binder.As a result of decreasing water/binder ratio,the total charge passing through the fly ash concrete reduced about 43%at 28days,but only about 10%at 90days.From these results,it can be concluded that the decrease in the water/binder10203040506070100PC-6050S-6050F-6025FS-60MixtureC u b e c o m p r e s s i v e s t r e n g t h (M P a )pressive strengths of concretes with water/binder ratio of 0.6020406080100100PC-3850S-3850F-3825FS-38MixtureC u b e c o m p r e s s i v e s t r e n g t h (M P a )pressive strengths of concretes with water/binder ratio of 0.3855003721613762000400060008000100PC-6050S-6050F-6025FS-60MixtureR a p i d c h l o r i d e p e r m e a b i l i t y (C o u l o m b )2890Fig.5.Rapid chloride permeability test results of concretes with water/binder ratio of 0.60206144217500100015002000100PC-3850S-3850F-3825FS-38MixtureR a p i d c h l o r i d e p e r m e a b i l i t y (C o u l o m b )90Fig.6.Rapid chloride permeability test results of concretes with water/binder ratio of 0.38D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S o u t h e a s t U n i v e r s i t y o n 12/12/13. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .ratio affects the RCPT value of the portland cement concrete more than those of the concretes with high amount of pozzolans.For the water/binder ratio of 0.38;at 28days,the concrete with the ternary binder and the slag concrete have the lowest RCPT values,which are about 20%of the portland cement con-crete.At 90days,however,the fly ash concrete has the lowest RCPT value which is about 8%of the portland cement concrete value.At the low water/binder ratio,the chloride permeability of pozzolanic concretes also decreased substantially between 28and 90days.For the 0.38water/binder ratio,between 28and 90days the RCPT value of portland cement concrete decreased only about 6%,however,decreases of 48,73,and 44%were obtained for the slag concrete,fly ash concrete,and the ternary binder concrete,respectively.In this study,the total replacement ratio of portland cement by the pozzolanic materials was 50%for all the mixtures.In the binary blended mixtures,concretes contain 50%slag or fly ash,and the ternary blended mixtures contain 25%slag and 25%fly ash which also correspond to 50%replacement.As seen in Figs.5and 6,for both water/binder ratios,the RCPT results of the ter-nary blended mixtures at 28days are slightly lower than those of the slag or fly ash concretes.At the age of 90days,however,the RCPT results of the ternary blended concretes are almost the same as the slag concretes and higher than those of the fly ash concretes.For the ternary blended mixtures,the reduction of the RCPT results between 28and 90days were also not lower com-pared to those of the binary blended concretes.In theory,for the ternary blended mixtures with equal percentage of fly ash and slag replacement,greater reduction in chloride permeability may be expected compared to those of the binary blended mixtures.However,based on the test results,it seems that such an improve-ment was not obtained by the ternary blended mixtures prepared.The fly ash and slag used have almost the same Blaine finenesses which indicate that they have similar particle sizes.Due to this similar particle sizes,the particle packing in the ternary blended mixtures may not be substantially different compared to those of the binary blended concretes and as a result the RCPT of the ternary blended concretes were not substantially lower than those of the binary blended concretes.In this study,all the specimens were cured in water until the testing day and for both water/binder ratios,the substantial reduc-tion of the chloride ion permeability of pozzolanic concretes be-tween 28and 90days indicates the high pozzolanic activity of the pozzolans taking places during this period.The ASTM C 1202-05͑ASTM 2005͒classifies concretes in terms of chloride ion pen-etrability and based on this classification,the concretes containing the ground fly ash and slag can be considered as concretes of very low permeability.The lower chloride permeability of the concretes with high volume pozzolans is a result of a denser microstructure.The poz-zolanic reaction may cause lower amount of capillary pores and clogging of the pores,which reduces chloride ion transport in concrete ͑Li and Roy 1986͒.Improvement of the aggregate-cement paste interface by the pozzolanic reaction may also play a role in decreasing the chloride ion permeability.Better chloride ion resistance of high volume fly ash concretes was also shown in other studies ͑Sengul et al.2005;Zhang et al.1999͒.The ground fly ash and slag used in this study has a high fineness which may have contributed to obtaining lower chloride ion permeability ͑Dhir and Jones 1999͒.Decreasing the water/cement ratio of a concrete reduces the amount of capillary pores which are mainly responsible for thepermeability of the concrete.Even though the RCPT value of the portland cement concrete is reduced about 70%by lowering the water/cement ratio,the values for the portland cement concrete at 0.38water/cement ratio are still 2times or even more higher than those of the concretes with pozzolans at 0.60water/binder ratio.This result indicates that to reduce the chloride permeability of portland cement concrete,inclusion of pozzolans are more effec-tive than reducing the water/cement ratio.Reduced capillary pores and reduction in their connectivity due to the pozzolanic reaction and better particle packing may be the reasons behind the better performance of the concretes with high amount of poz-zolans.Also,as indicated above,between the ages of 28and 90days,the chloride permeability of the concretes with pozzolans decreased substantially compared to those of the portland cement concretes.Pozzolanic reaction is relatively slow compared to the hydration of portland cement,which is the main reason of the low early age strength or high early age permeability of the concretes containing high volumes of pozzolanic materials.At later ages,however,the pozzolanic materials can be more effective in im-proving concrete properties due the pozzolanic reaction continu-ing at a higher rate for a longer period.It should also be noted that curing conditions is more important for such concretes.As seen in Table 5,the decrease in the water/binder ratio was obtained by both reducing the water amount and increasing the binder content which may have also contributed to the better per-formance of the low water/binder ratio concretes.Studies show that,for a same water/binder ratio,increasing the binder content can also help to reduce the permeability of the concrete ͑Buenfeld and Okundi 1998;Dhir et al.1996͒.OptimizationOptimization is a procedure for obtaining the best possible option and it is an important tool for decision making process.This procedure is based on defining performance criteria ͑objective functions ͒,independent and dependent variables,and formulation of the parameters based on constraints ͑Brandt and Marks 1993͒.For the optimization of concrete mixtures;the performance crite-ria may be the strength,permeability properties,fracture proper-ties,durability characteristics,cost,or other concrete properties.The independent variables,for example,may be the amounts of constituent materials.The responses ͑dependent variables ͒,which are based on the independent variables,are compared to the per-formance criteria.In the optimization of concrete mixtures,con-crete properties such as the compressive strength obtained for a given mixture design may be one of the responses.Optimization usually involves considering several responses simultaneously,such as high strength and low cost.To optimize several responses,multicriteria optimization techniques were used in this study.A useful approach for the optimization of multiple responses simultaneously is to use desirability functions which reflect the levels of each response in terms of minimum and maxi-mum desirability ͑Sengul et al.2005͒.A desirability function ͑d j ͒varies over the range of 0Յd j Յ1.In case of maximizing and minimizing the individual responses,d i is defined by Eq.͑1͒and ͑2͒,respectively ͑Myers and Montgomery 2002͒d j =ͫY j −min f jmax f j −min f jͬt͑1͒D o w n l o a d e d f r o m a s c e l i b r a r y .o r g b y S o u t h e a s t U n i v e r s i t y o n 12/12/13. C o p y r i g h t A S CE .F o r p e r s o n a l u s e o n l y ; a l l r i g h t s r e s e r v e d .。
河北单招考试英语真题试卷
河北单招考试英语真题试卷一、听力理解（共20分）Section A（共10分，每题1分）1. What is the man going to do after work?A. Go to the gym.B. Go to the library.C. Go to the cinema.2. What is the weather like today?A. Sunny.B. Rainy.C. Snowy....10. What does the woman suggest for dinner?A. Chinese food.B. Italian food.C. Fast food.Section B（共10分，每题2分）11. What is the main topic of the conversation?A. Travel plans.B. Job interviews.C. Academic research.12. Why does the man seem upset?A. He lost his wallet.B. He missed his bus.C. He failed an exam....20. What is the woman's opinion about the new policy?A. She agrees with it.B. She disagrees with it.C. She is indifferent to it.二、阅读理解（共30分）Passage 1（共10分，每题2分）A new study has shown that...21. What is the main idea of the passage?22. According to the study, what is the effect of...23. What does the author suggest...24. What can be inferred from the passage?25. What conclusion can be drawn from the passage?Passage 2（共10分，每题2分）The history of the internet dates back to...26. When did the internet originate?27. What was the purpose of the internet in its early days?28. How has the internet evolved over time?29. What impact has the internet had on society?30. What does the future hold for the internet according to the passage?Passage 3（共10分，每题2分）In recent years, environmental issues have become...31. What is the focus of the article?32. What are some of the challenges faced by environmentalists?33. What solutions are proposed in the article?34. What role does the government play in environmentalprotection?35. What can individuals do to help the environment?三、完形填空（共20分，每题1分）36. The company has recently undergone a series of changes, and the employees are feeling _______.A. excitedB. anxiousC. indifferentD. relieved37. Despite the challenges, the management team is _______ about the future.A. optimisticB. pessimisticC. uncertainD. skeptical...55. The final decision will be made after a thorough_______ of all the options.A. evaluationB. discussionC. analysisD. comparison四、语法填空（共10分，每题1分）56. The project, _______ (complete) in three months, will bea major achievement for the company.57. She is _______ (talent) than her sister and has won several awards.58. The museum, _______ (build) in 1850, is a historical landmark....65. _______ (be) there any updates on the situation?五、翻译（共10分）66. 请将下列句子从中文翻译成英文：a. 这个项目的成功取决于团队的合作。
Research_on_the_Application_of_New_Inorganic_Chemi
Research on the Application of New Inorganic Chemistry Technology in Heat ProcessingQingfeng WangDepartment of Chemistry, Taishan University, Taian 271021, Shandong, PR ChinaABSTRACTWith the increasing development of science and technology, the heatprocessing of metals has become a very important subject, and theresearch on the application of new inorganic chemistry techniques inheat processing and related textbooks is almost blank. This paper brieflydescribes the reaction mechanism in heat processing using inorganicchemical reaction principles to solve the problem of applying chemistry inproduction.KEYWORDSInorganic chemistry; Technology; Heat processing; ApplicationsDOI: 10.47297/taposatWSP2633-456910.202304011 IntroductionInorganic chemistry textbooks hardly introduce chemical reactions other than aqueous systems such as chemical reactions at high temperatures, which can be of great help to expand students’ knowledge and combine with production practice. Among them, the heat processing of steel in various media is both high-temperature chemistry and the application of new inorganic technology in heat processing.2 Overview of Inorganic ChemistryInorganic chemistry is a study of the performance of various metals and substances and their interaction with the laws of experimental analysis and chemical principles in addition to hydrocarbons and derivatives,and it is one of the fastest growing fields of research in the field of organic chemistry.Although the number of inorganic substances is less than ten percent of all known chemical substances, inorganic substances are the majority of known basic properties, that is, although the number of organic substances exceeds the number of inorganic substances, the number of substances contained is much lower than that of inorganic substances, and the variety of substances is much lower than that of inorganic substances. This has resulted in a much smaller number of organic reactions than inorganic reactions (many inorganic-related reactions may only be carried out on one substance and do not conform to the general universality of organic synthetic reactions). The notable advances made in inorganic chemistry research in recent years have been mainly in the areas of physical chemistry of biosolids, coordination chemistry, etc., which to some extent have kept pace with the international level of progress. With the support of the National Natural Science Foundation of China for more than ten years, and with the joint efforts of a large number of researchers in bioinorganic chemistry, the main research results of bioinorganic chemistry have developed further in ten years, and the main research scope has risen from small biological ligandsVol.4 No.1 2023 to biological macromolecules; from the study of isolated macromolecules to the study of new life systems; in recent years, the research on bio-molecules has also been carried out. In recent years, we have also started to study inorganic chemistry at the biomolecular level, and the research level has been gradually increased. Inorganic chemistry in China has formed a relatively stable scientific research direction in the fields of interaction between metal complexes and biopolymers, chemical interaction with metalloproteins, physicochemical mechanisms of biological reactions with metal molecules, inorganic medicinal chemistry, biomineralization, etc., and the researchers are getting younger and younger. However, the overall level of bioinorganic chemistry in China is still lower than foreign standards, mainly because of insufficient investment in research, relatively long research time, and the most obvious difficulty is the lack of outstanding young researchers. The rapid development of radiochemistry has also shown the above advantages, and one of the key reasons is the need to support young researchers to stand out.3 The Decarburizated Heating of Steel without OxidationAt room temperature, the oxidation of steel in the air is slow, but when heating steel above 800 ℃, the oxidation rate increases greatly, resulting in a large number of high-quality steel corrosion and modification, if it is made in the salt furnace heating, vacuum heating or atmosphere protection, it can solve a series of problems such as oxidation and decarburization of steel when heated in air. In fact, decarburization also belongs to the oxidation reaction.4 The Alloying of Steel SurfaceThe alloying of steel surface is the main means to improve the surface properties of steel (corrosion resistance, corrosion wear resistance and galling resistance, etc.). In inorganic chemistry, it is used to create single reactions, most of them can be used for alloying steel surfaces. The steel surface is obtained not as a monomer, but as an alloyed layer, whose main reactions are chemical reactions: Fe + Al (e) = Fe + Al (e) (aluminum thermal immersion); thermal decomposition of compounds: 2C0=C+CO2 (carbon penetration reaction); reduction reactions: NH3=N+3/2H2 (nitriding reaction); thermal reduction of metals: CrCl2+Fe=Cr+FeCl2 (chromium penetration reaction) ; hydrogen reduction: CrCl2+H2=Cr+2HCl (chromium permeation reaction); Na2B4O7+2SiC+8Fe=4Fe2B+2C0+Na2O·2SiO2; molten salt electrolysis: Na2B4O7+8Fe=2Na+4 Fe2B +7/202. In terms of electrolysis of aqueous solutions, organic salts (HCOOK, CH3COOK), etc. in aqueous solutions , steel as the cathode, electrolysis can make carburization in steel, but the surface alloying reaction of some steels is more complicated. For example, NH4Cl and aluminum powder’s carburization reaction is: 3NH4Cl+Al=AICl3+3NH3+3/2H2 (NH3 can be decomposed reaction out of gas N2, H2); 2 AICl + Al = 3 AICl3 3AICl2 + Fe = Fe-Al + 2 AlCl3 (pulverization reaction).5 The Application of New Inorganic Technology in Heat ProcessingFirst, it is only applicable to the water gas reaction between gases and other low carbon steel without oxidation protection heating: (O2 + H2 = C0 + H20 (g) first remove H2O and CO2 in it with deep-cooled silicon molecular sieve, you can get the protective gas with very low amount of CO2, H2O (g) and H2 to expand its use. If O2 remains in the matrix, it can be removed by palladium A molecular sieve or silver molecular sieve (the former contains PdO, the latter contains Ag20, both need reductionTheory and Practice of Science and Technologytreatment at present.) Pd-A molecular sieve is used as H2 and O2 reaction catalyst, and should be aggravated when deacidifying. The silver molecular sieve is used as a reducing agent and should not be weighted when deoxidizing. The above molecular sieves can be used to further purify N2, Ar, H2 and other gases for heat treatment.Second, adding reducing agent (NaH2PO3) and buffer (NaAc) to the metal salt solution such as NiSO4 in amorphous alloy chemical plating, and processing steel at a certain temperature and pH, can obtain amorphous alloy plating with Ni-P on the surface, and the amorphous alloy plating is better than normal in terms of corrosion, and can be used as a resist component in chemical and other devices. For example, the plating is annealed at 400°C with a microhardness of 1000 kg-mm-1. This method used for metal cutting and corrosion inhibitor parts is known as nickel phosphate infiltration.Third, the application of chemical vapor deposition technology: by chemical vapor deposition on the surface of steel, you can obtain good corrosion of carbon, nitrogen, boron, oxide film (also known as coating). For example, some products of inorganic synthesis of Si3N4 is a high-temperature ceramic raw materials, Al2O3 synthesis of Cr2O3, Ti2 + Fe2O3 - MgO + CoO can obtain artificial red, co-colored gemstones.Fourth, the application of stable ZrO2 solid electrolyte: add 15% mol CaO to pure ZrO2 solid, after high temperature melting into an exchange solid solution, you can get a stable CaF2 type cubic crystal. When CaO is added to ZrO2, the O2- number per -CaO is less than half of -ZrO2 when 15% molCaO is added, 7.5% O2- vacancy will be generated in the crystallization, if different oxygen is ejected from both sides of the stable ZrO2, this O2- vacancy will generate electric conductivity and thus electric potential. Using stable ZrO2 as electrolyte (ZrO2 as small test tube) and air as reference electrode, RTLnPO2 in the atmosphere can be measured. the application process is as follows: (1) PtO2(atmosphere)/ZrO2-CaO/O2(air)Pr(+); when PO2(atmosphere)<PO2:(air), O2 in the air occurs and moves into the atmosphere through ZrO2. Oxygen in the atmosphere comes from the following reactions: CO2-CO system: Co2=CO+1/2O2; H2O-H2 system: H2O=H2+1/2O2; CO2-H2O-CO-H2 system: CO2+H2O=CO+H2+O2. The following reactions can also determine the carbon activity (or carbon potential) of the atmosphere ao. CO2+C=2CO K1= P2co/P co2•ao ; CO+ 1/2O= =CO2 K2=Pco2/P co Po2; ao=1/ K1K2·P co1/2P o21/26 Objections to the Inorganic Chemical Reactions Described in the Currently Used Professional Textbooks or MonographsSeveral other chemical reaction equations are frequently recorded in heat processing monographs, as described below.(1) Boron penetration reaction (including other metal penetration reactions)Gas phase boron permeation is the reaction documented in the following reaction equations in monographs or monograph textbooks. BCL3+Fe= Fe B+3/2HCl2 (decomposition reaction); BCL3+3/2H2+ Fe = FeB+3HCl (reduction reaction); BCL3+5/2Fe= FeB+3/2FeCl2 (substitution reaction) ΔG. -T relationship curve for the above reaction. If the reaction is reliable, ΔG°=0 in the reaction of H2 reduction of BCI3 at about 1500°C, i.e. the temperature of boron penetration treatment on the steel surface should exceed 1500°C. However, the actual treatment temperature should be around 900°C. The difference between the two is that the above reaction equation does not represent the true reaction. The boron penetration reaction is changed to BCl3+Fe=Fe+3/2Cl2 BCL3+3/2H2+Fe=FeB+3HCl;BCL3+5/2 Fe=FeB+3/2 FeCl2, the resulting FeB (or Fe2B) is reflected belowVol.4 No.1 2023 900 ℃, so this result is more in line with reality. In addition, according to the difference of the post-reaction equation, it can be seen that the substitution reaction is easier than the reduction reaction. That is, the steel is easy to be corroded by BCI3 in this environment, forming the boron penetration of FeB, but this boron penetration technology is difficult to be widely used in production at present. There are also works that Na2CO3 for the salt furnace in the salt solvent of harmful impurities, electrolytic leaching of boron anode reaction intermediate product of B4O7, which in theory and in practice are not based.(2) The carbon and nitrogen of high-temperature gas’s penetrationGenerally it should be written CH4+NH3=HCN+3H2；CO+NH3=HCN+H2O; HCN=[C]+[N]+1/2H2, [C], [N] indicate the carbon and nitrogen atoms that can penetrate into the surface layer of steel. The first two equations in the reaction equation actually synthesize the HCN reaction. On the other hand, HCN is stable at high temperatures and generates HCN decomposition, which precipitates carbon and nitrogen on the steel surface. Because CH4, CO, NH3 itself leaches carbon and nitrogen on the steel surface by thermal decomposition, the latter is less stable than HCN in three ways. The exhaust gas discharged from the reaction furnace contains a small amount of HCN, but from the HCN pyrolysis formula, HCN is the equilibrium product of gaseous carbon and nitrogen co-infiltration, and the presence of HCN is very small amounts, which has begun to be applied in the carburizing and nitrogen high-temperature heat treatment process.7 ConclusionThere is a lack of theoretical research and little relevant information on the application of new inorganic chemical techniques in heat processing. Also, more relevant researchers are needed. The authors have done some rough research in the practice of teaching inorganic chemistry for the readers’ reference. Please point out any inappropriate points.About the AuthorQingfeng Wang (1981-03), ShandongTaian male, the Han nationality, lecturer, master, inorganic chemistry and organic chemistry.References[1] He Lingbo, Wang Sifang, Wang Xitong. New Technology of Nuclear Waste Capacity Reduction Treatment[J]. One HeavyTechnology,2018(05):1-6.[2] Zhang Liming, Gao Yuming. Thermal Analysis Technology and Its Application in Catalysts[J]. Tianjin ChemicalIndustry,2015,29(02):32-33+60.[3] Wang Meng, Zhao Bin, Lin Lin, Chen Chao, He Danong. Research Progress on Supercritical Fluid Technology-AssistedSynthesis of TiO_2 Nanomaterials[J]. Materials Guide,2013,27(23):120-24.。
有序介孔氮掺杂碳负载三氧化二铁的制备及其催化氧还原性能
收稿日期：2020⁃07⁃30。
收修改稿日期：2020⁃10⁃27。
国家自然科学基金(No.21306132)和国家重点研发计划基金(No.2016YFB0600305)资助。
＊通信联系人。
E⁃mail ：************.cn第37卷第2期2021年2月Vol.37No.2243⁃250无机化学学报CHINESE JOURNAL OF INORGANIC CHEMISTRY有序介孔氮掺杂碳负载三氧化二铁的制备及其催化氧还原性能肖周荣1侯放1张香文1,2王莅1,2李国柱＊,1,2(1天津大学化工学院，天津300072)(2天津化学化工协同创新中心，天津300072)摘要：制备了有序介孔氮掺杂碳负载三氧化铁，有效降低了氧还原的过电势。
通过扫描电子显微镜、透射电子显微镜、氮气吸附-脱附测试、粉末X 射线衍射、X 射线光电子能谱、拉曼光谱等技术表征了所制备的催化剂的物理化学性质。
此外，用旋转圆盘电极测试了其在碱性条件下对氧还原反应的催化活性和选择性。
实验结果表明：氮气热解后铁以三氧化二铁的形式负载于有序介孔氮掺杂碳中，其比表面积达到755cm 2·g -1。
拉曼和X 射线光电子能谱结果表明，加入铁前驱体后所制备的催化剂石墨化程度有所提升、阻抗降低、导电性增加。
在碱性条件下，Fe 2O 3@NC 催化剂呈现出4电子氧还原反应，其起始电位(-0.01V vs Ag/AgCl)和半波电位(-0.13V vs Ag/AgCl)与商用20%Pt/C 相当。
此外，该催化剂具有较好的抗甲醇性能且其恒电压稳定性优于商用Pt/C 。
Fe 2O 3@NC 催化剂用于锌-空电池放电测试，其放电功率可以达到88mW·cm -2，是商用Pt/C 的1.29倍。
关键词：电催化氧还原；燃料电池；Fe 2O 3；氮掺杂的碳；介孔中图分类号：O614.81；O643.3文献标识码：A文章编号：1001⁃4861(2021)02⁃0243⁃08DOI ：10.11862/CJIC.2021.024Preparation of Ordered Mesoporous Nitrogen Doped CarbonSupported Fe 2O 3for Oxygen Reduction ReactionXIAO Zhou⁃Rong 1HOU Fang 1ZHANG Xiang⁃Wen 1,2WANG Li 1,2LI Guo⁃Zhu ＊,1,2(1School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China )(2Collaborative Innovation Center of Chemical Science &Engineering,Tianjin University,Tianjin 300072,China )Abstract:Ordered mesoporous nitrogen doped carbon supported iron oxide was prepared,which effectively reducedthe overpotential of oxygen reduction.The physicochemical properties of the as⁃prepared catalysts were character⁃ized by scanning electron microscopy,transmission electron microscopy,nitrogen adsorption⁃desorption test,powder X⁃ray diffraction,X⁃ray photoelectron spectroscopy and Raman spectroscopy.In addition,the activity and selectivi⁃ty for oxygen reduction reaction was tested by rotating disc electrode under alkaline conditions.The results show that iron was loaded in ordered mesoporous nitrogen doped carbon in the form of Fe 2O 3after nitrogen pyrolysis,andits specific surface area reached 755cm 2·g -1.The results of Raman and X⁃ray photoelectron spectroscopy show that the graphitization degree of the catalyst increased with adding iron precursor.The impedance was decreased and its conductivity was increased.Under alkaline conditions,Fe 2O 3@NC exhibited a 4⁃electron oxygen reduction reaction,and its initial potential (-0.01V vs Ag/AgCl)and half slope potential (-0.13V vs Ag/AgCl)were comparable tothose of commercial 20%Pt/C.In addition,the catalyst had superior methanol resistance and excellent constant voltage stability compared with commercial Pt/C.The discharge power of Fe 2O 3@NC reached 88mW·cm -2,whichwas 1.29times that of commercial Pt/C.Keywords:oxygen reduction reaction;fuel cell;Fe 2O 3;nitrogen doped carbon;mesoporous无机化学学报第37卷0引言燃料电池、金属-空气电池因其能量转换效率高且清洁无污染被认为是最有应用前景的能源转换技术[1⁃2]。
溶出条件对印尼铝土矿各指标影响研究
Na2OK Al2O3 Na2OT Na2OC 176 201.3 196 20 173 199 193.4 20.3
Rp 1.144 1.150
SiO2 1.336
Fe2O3 0.005
174 198 194 20 1.138
2
1.483 0.003
173 197 192.6 19.6 1.139
含， 考 溶岀
含量对溶岀 以
及各 指标 耗影响情况。
由图1看岀：随着溶岀料浆固含量提升，溶
岀 Rp
高， 碱
率不
；同
时溶岀硅基相对溶岀率波动较小，保持在100%左
右，
印尼铝土矿 溶岀。在一进料固含
量间
，
进 量 ， 溶岀
常稳定。在 产量同时，考虑
率最大化,
量高进 含。
3.1.2 进料固含量对碱耗及硅量指数影响关系
进 含量的不
，碱耗波动较小，
固含量对碱耗影响较小。同时，溶岀液硅量指数
不断下降，
含量为255 g/L ，硅量指 :
低，较，
。结
含量硅
量指 化进
，
2- 3。
80
150
70
140
60
130
50
120
40
110 ts
30
100
20
90
10
80
220 230 240 250 260 270 280
固含量/(g/L)
11.84
0.89
0.16
0.04
0.05
3.16
印尼-2
47.78
11.80
14.89
0.76
0.16
0.06
几种不锈钢和镍在高温碱液中的腐蚀行为
几种不锈钢和镍在高温碱液中的腐蚀行为殷华敏;李国明;陈珊;刘亚强;孟令岽【摘要】目的为了减少制碱设备在碱液蒸发浓缩阶段发生的严重腐蚀.方法采用静浸泡、电化学稳态极化测试技术、光学显微镜和扫描电镜(SEM)观察,以及XRD,XPS腐蚀产物分析等试验方法,研究几种材料(26-1,30-2,18-8Ti和Ni)在高温高浓碱液中的腐蚀行为.结果在150℃、50％NaOH的碱液中,加入NaClO3会使18-8Ti的耐蚀性提高,却使镍的耐蚀性降低.只有碱液中NaClO3含量适量时(如0.15％NaClO3),才能使26-1和30-2和耐蚀性提高,NaClO3含量过多或过少,均使26-1和30-2耐蚀性降低.结论 Cl-的加入能够降低镍和18-8Ti和耐蚀性,而使30-2的耐蚀性提高,与18-8Ti相比,26-1和30-2的耐蚀性有着显著的提高.%Objective To reduce severe corrosion of alkali production equipment in evaporation and concentration of alkali solution.Methods Static immersion,electrochemical static polarization measurement technology,optical microscope and scanning electron microscope were used for observation.Test methods such as XRD,XPS corrosion product analysis,etc.were used to analyze corrosion behaviors of several kinds of materials (26-1,30-2,18-8Ti and Ni) in high temperature and high concentration alkali solution.Results The corrosion resistance of 18-8Ti would increase if NaClO3 was added to 50％NaOH at 150 ℃.But the corrosion resistance was nickel decreased.The corrosion resistance of 26-1 and 30-2 would increase only if NaClO3 in alkali solution is proper (0.15％NaClO3 for example);otherwise,the corrosion resistance of 26-1 and 30-2 would decrease.Conclusion Adding Cl-increases corrosion resistance ofnickel and 18-8Ti,and thus increases the corrosion resistance of 30-pared with 18-8Ti,the corrosion resistance of 26-1 and 30-2 increases more apparently.【期刊名称】《装备环境工程》【年(卷),期】2017(014)001【总页数】5页(P9-13)【关键词】不锈钢;镍;高温碱液;腐蚀【作者】殷华敏;李国明;陈珊;刘亚强;孟令岽【作者单位】海军工程大学理学院材料科学与工程系,武汉430033;海军工程大学理学院材料科学与工程系,武汉430033;海军工程大学理学院材料科学与工程系,武汉430033;海军工程大学理学院材料科学与工程系,武汉430033;海军工程大学理学院材料科学与工程系,武汉430033【正文语种】中文【中图分类】TJ07;TG172对制碱业影响很大的技术难题之一，就是生产过程中，设备及管道、阀门等的腐蚀问题。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
To study the effect of adding Fe2O3 nanoparticles on the morphology properties and microstructure ofcement mortarN. Abdoli Yazdi 1, M. R. Arefi 2,*, E. Mollaahmadi 2, B. Abdollahi Nejand 31.Department of Civil Engineering, Yazd Branch, Islamic Azad University, Yazd Iran2.Department of Civil Engineering, Taft Branch, Islamic Azad University, Taft, Iran3.Nanomaterial Research Group, Academic Center for Education, Culture and Research (ACECR) on TMU, Tehran, Iran*arefi@taftiau.ac.irAbstract: In this study, research has been done on the compressive and tensile strength of cement mortar containing Fe2O3 nanoparticles in the amounts of 1, 3 and 5% by weight of cement. The results show that the mechanical properties of samples containing 1% and 3% Fe2O3 nanoparticles are desirable than the ordinary cement mortar. SEM study about the micro structure of cement mortar containing nanoparticles and ordinary cement mortar showed that Fe2O3 nanoparticles fills the pores completely and reduces the large crystals of Ca(OH)2 and the hydrate products are denser and compact. The mechanical properties results showed that by increasing Fe2O3 nanoparticles up to 5% reduces the mechanical properties.[N. Abdoli Yazdi, M. R. Arefi, E. Mollaahmadi, B. Abdollahi Nejand. To study the effect of adding Fe2O3 nanoparticles on the morphology properties and microstructure of cement mortar. Life Science Journal, 2011; 8(4):550-554] (ISSN: 1097-8135). .Keywords: Mechanical properties; Fe2O3 nanoparticles; cement mortar; SEM, microstructure1. IntroductionIn recent years, much attention is in the application of nanoparticles in civil engineering, because nanoparticles due to its small size possess unique properties such as high specific surface area and high activity. If nano materials are combined with traditional building materials, this may lead to production of building materials with unique properties and be useful for construction industry. On the other hand, building materials based on Portland cement (concrete, cement mortar, hardened cement paste), is one of the most used and important components used in the construction industry. Much research has been done on the partial replacement of cement with supplementary cementing materials such as Pozolon and nanoparticles to improve their mechanical properties. Many researchers have studied the mechanical properties of cement based materials containing nanoparticles.Researches done shows that adding nano-particles to cement-based materials improves the mechanical properties. Hui Li and et al in 2005 have examined the abrasion resistance of concrete containing TiO2and SiO2nanoparticles. The experiment results shows that the abrasion resistance of concrete containing nanoparticles has improved and abrasion resistance of concrete containing nano TiO2 is more than the abrasion resistance of concrete containing nano SiO2 [2]. Other research results show that adding SiO2nanoparticles can improve the microstructure of the cement and result in the increase of freezing resistance with high performance concrete [3]. This is an important property for concrete exposed to frost. Ali Nazeri et al in 2010 proved that addition of TiO2 and ZnO2 nanoparticles increases the concrete compressive strength. These particles also reduce the workability of fresh concrete where in this case it is essential in the use of plasticizer in high percentage of nanoparticles [4, 5]. Mohammad Reza Arefi and et al have studied the effect of adding SiO2 particles with diameters and in different amount to the cement mortar. The research results showed that nanoparticles due to higher specific surface area improve the mechanical properties and water permeability of cement mortar more than the micro-particles [6]. Studies done on the effect of adding nanoparticles to cement mortar shows that the nanoparticles reduces the amount and size of Ca(OH)2 crystals and needle shaped hydrates and takes position as a nucleus in the cement paste and progresses the hydration of cement having high activity. Cause to create a homogenous and denser cement matrix and ultimately leads to the improved mechanical properties of cement mortar [7-9]. Meral Oltulu and et al have investigated separately and combined the effect of adding nanoparticles of Fe2O3, Al2O3and SiO2to cement mortars containing silica fume. The research results show that adding these nanoparticles separately causes the increase of compressive strength and improved capillary permeability. But, the interaction of nanoparticles as binary and ternary combinations has a negative effect on the physical and mechanical properties of cement mortar [10].The research done on the addition of Fe2O3 nanoparticles to cement-based materials shows thatthe cement mortar containing nano-Fe2O3can sense its compressive stresses in elastic and inelastic system. Because nano-Fe2O3can change the electric resistance of cement mortar with the loading applied. This property is useful for the monitoring structural health [11]. The flexural, tensile and compressive strength of concrete is increased and reduces the setting time of concrete [12, 13]. Conflicting results has been shown about the optimized percentage of adding Fe2O3 nanoparticles. Lee and et al [7] showed that by adding nanoparticles to cement mortar, samples containing 3% nanoparticles has the highest mechanical properties but, the research results of Ali Nazeri and et al [12, 13] has shown that the best compressive strength is related to the sample containing 1% Fe2O3 nanoparticles.The aim of this study is to find the optimized percentage of adding Fe2O3nanoparticles and to achieve high strength mortar and finding mechanism to improve the mechanical properties of cement mortar.2. Material and Methods2.1. Materials and mixture proportionsASTM C 150 [14] Type II portland cement was used. The superplasticizer was a commercial sulphonated melamine formaldehyde polymer manufactured by vand chemie in Iran with relative density of 1.15. The content was adjusted for each mixture to ensure that no segregation would occur. Also, the distilled water was used for preparing all mixtures. Crushed silica sand was used with apparent density of 3.33 gr/cm3and the fineness modulus of 2.6. The sand was graded according to ASTM C33 [15] standard. The largest diameter of these aggregate particles was 4.75mm. The Fe2O3 nanoparticles were purchased from Skyspring Nanomaterials Inc. The characteristics of the Fe2O3 nanoparticles were shown in Table 1.Table 1. The characteristics of nanoparticlesNanoparticle type Diameter Speci cfisurfacearea (m2/g)Purity(%)Fe2O330 nm 60 99% The mixture proportions of the ordinary cement mortar and the cement mortar containing Fe2O3 nanoparticles were shown in Table 2. The ratio of the water to binder (the cement and Fe2O3 nanoparticles) was chosen 0.42. In this study the mixtures were examined with the cement replacement of 1%, 3% and 5% by weight of cement.Table 2: Mix proportion of samples (kg/m3) SamplenameWater Cement Sand Nano Fe2O3particles*SP *CO 150 360 1800 - -1NF 150 356.4 1800 3.6 3.683NF 150 349.2 1800 10.8 4.295NF 150 342 1800 18 4.9 *CO: Control- Ordinary cement mortar*SP: superplasticizer2-2- Sample preparationThe high homogenous dispersion of nanoparticles strongly depends on stable suspension preparation. Hence Fe2O3nano powder was mixed with the distilled water and stirred for 6-10 hours by rotational speed of 250-300rpm. At first, the suspension of the Fe2O3nanoparticles and the superplasticizer were mixed in the mixer for 30 second, where the cement was added to this mixture simultaneously. Thereafter, the sand, from finest to coarsest, was added gradually to the mixture, and the mixing continued until the complete homogenization of the mixture. Then, the mortar was poured into the standard mold. For tensile test, the briquette specimens with 75×25×25 mm dimension were utilized. The mortar was poured in two layers, both of them compressed by 4 impacts of a steel rod. In order to prepare the specimens of the compressive tests, the mortar was poured into molds to form cubes of size 50×50×50 mm in three layers alternatively, which all layers compressed by 10 impacts of a steel rod. The molded specimens were covered with a plastic layer for 24 hours and then were cured in water at the room temperature up to end of the seventh day. Six specimens were prepared for each test and the average result was reported.2-3 Test methodsThe apparatus made by ELE Company, England was used for performing the mechanical tests. The microstructure of the specimens was studied by the scanning electron microscopy (SEM) Hitachi S-4160. Compressive tests were carried out according to the ASTM C109 [16] and tensile tests were carried out according to the ASTM C190 [17].3. Results and Discussion3.1. Microstructure of samplesThe microstructure of samples is shown in figure 1. As shown in the figure, it can be seen in the microstructure the ordinary mortar samples of large crystals of Ca(OH)2. The microstructure of cementmortar is non dense and the voids can be observed. Microstructure of the sample containing 1% nanoparticles is similar to ordinary mortar. In both large crystal Ca(OH)2 is observed with the difference that the voids are reduced and the mortar structure is more denser. With the increase of nanoparticles quantity up to 3%, microstructure has improved completely and achieved better density. As shown in figure 1d, in samples containing 5% nanoparticles because of the agglomeration of nanoparticles voids are formed. These microstructures with the reduction of mechanical propertiesin these samples are appropriate.Figure 1. Microstructure of the samples, a) Sample of CO. b) Sample of 1NF. c) Sample of 3NF. d) Sample of 5NF3.2. Mechanical propertiesResults of compressive strength, tensile strength after curing for seven days is given in table 3. It can be understood from the table that the sample containing 1 and 3% Fe 2O 3 nanoparticles, the mechanical properties has improved than the ordinary cement mortar. As indicated in figure 1 in a sample containing 1% nanoparticles than ordinary samples the structure of cement mortar is compacted, but still Ca(OH)2 large crystals is observed. With the increasing quantity of nanoparticles up to 3% the Ca(OH)2 large crystals are removed and the microstructure of the mortar is completely compacted. The mechanism of Fe 2O 3 nanoparticles which increases the strength of cement mortar can be described as follows that the addition of Fe 2O 3 nanoparticles reduces the quantity and size of Ca(OH)2 crystals and fills the voids of C-S-H gel structure and ultimately the structure of hydrated products are denser and compact [7]. But, the increased Fe 2O 3 nanoparticles up to 5%, the mechanical properties reduces. This issue is because nanoparticles due to their high surface energy have the tendency towards agglomeration. When nanoparticles are over added to the mortar it is not uniformly distributed in cement mortar and due to agglomeration, weak zone appear in the cement mortar.This phenomenon can be explained as when the nanoparticles are uniformly distributed in cement mortar each particle has a cubic pattern and distance between the nanoparticles is adjustable. After beginning the cement hydration process the hydrated product are distributed and surrounds the nanoparticles as the nucleus. If the amount and distance between the particles is appropriate, nanoparticles prevents the growth of Ca(OH)2 crystals [2]. The past research of these researchers show that with excessive increase of nanoparticles quantity, the nanoparticles distance decreases and Ca(OH)2 crystals due to limited space cannot grow enough and finally the crystal quantity is reduced [18]. This factor along with the agglomerated nanoparticles causes the mechanical properties of the sample 5NF is lower than the ordinary mortar sample. Thus the effect of the nanoparticles agglomeration and non-desirable influence on the entire structure causes local cracks and ultimately reduces the mechanical properties.The results show that the addition of Fe 2O 3 nanoparticles, increasing amount of compressive strength is more than tensile strength. The reason for this is the presence of micro cracks in the cement mortar. The impact of these micro cracks on tensile strength is greater than the compressive strength [2, 19].Table 3: Mechanical properties of samplesSample nameCompressive strength Tensile strength (MPa) amountPercent increased (%)(MPa) amountPercent increased (%)CO 11.96 - 1.51 - 1NF 18.71 56.44 2.03 34.43 3NF 20.81 74 2.25 49 5NF 10.08-9.71.25-17.22510152025CO 1NF 3NF 5NFC o m p r e s s i v e s t r e n g t h (M P a )Figure 2. Compressive strength of samples0.511.522.5CO 1NF 3NF 5NFT e n s i l e s t r e n g t h (M P a )Figure 3. Tensile strength of samples4. ConclusionWith respect to the experimental results oftensile and compressive strength it is expected that adding of Fe 2O 3 nanoparticles up to 3% by weight of cement can act as a filler for strengthening the micro structure of cement and also reduces the quantity and size of Ca(OH)2 crystals and fill the voids of C-S-H gel structure and finally structure of hydrated product is compacted and denser. With the increase of nanoparticles quantity up to 5% there is decrease in nanoparticles distance and Ca(OH)2 crystal due to limited space cannot grow to appropriate size. This factor along with the agglomerated nanoparticlescauses the mechanical properties of the sample 5NF is lower than the ordinary mortar sample.Corresponding Author: Mohammad Reza ArefiDepartment of Civil Engineering, Taft Branch, Islamic Azad University, Taft, IranMember of Young Researchers Club, Islamic Azad University, Yazd, Iran E-mail: arefi@taftiau.ac.irReferences1. Zhang MH, Li H. Pore structure and chloridepermeability of concrete containing nano-particles for pavement. Constr Build Mater 2011; 25: 608–616.2. Li H, Zhang MH, Ou JP. Abrasion resistance ofconcrete containing nano-particles for pavement. Wear 2006; 260: 1262–1266.3. Baomin W, Lijiu W, Lai FC. FreezingResistance of HPC with Nano-SiO 2. J Wuhan Univ Technol-Mater(Sci. Ed) 2008;23:85-8. 4. Nazari A, Riahi S, Riahi S, Shamekhi SF andKhademno. Assessment of the effects of the cement paste composite in presence TiO 2 nanoparticles. Journal of American Science 2010;6:43-46.5. Riahi S, Nazari A. Physical, mechanical andthermal properties of concrete in different curing media containing ZnO 2 nanoparticles. Energy and Buildings 2011; 43:1977–1984.6. Arefi MR, Javaheri MR, Mollaahmadi E, ZareH, Abdollahi Nejand B, Eskandari M. Silica nanoparticle size effect on mechanical properties and microstructure of cement mortar. Journal of American Science, 2011;7:231-238.7. Li H, Xiao H.G, Yuan J, Ou J. Microstructure ofcement mortar with nano-particles. Compos: Part B: Eng 2004; 35: 185–9.8. Byung-Wan Jo, Chang-Hyun Kim, Ghi-ho Tae,Jong-Bin Park. Characteristics of cement mortar with nano-SiO 2 particles. Construction and Building Materials. 2007;21:1351–1355.9. Qing Y, Zenan Z, Deyu K, Rongshen C.Influence of nano-SiO 2 addition on properties of hardened cement paste as compared with silica fume. Constr Build Mater 2007;21:539–45.10. Oltulu M, Sahin R. Single and combined effectsnano-SiO 2, nano-Al 2O 3 and nanoFe 2O 3 powders on compressive strength and capillary permeability of cement mortar containing silica fume materials. Science and Engineering A 528 2011: 7012– 7019.11. Li H, Xiao HG, Ou JP. Study on mechanical andpressure-sensitive properties of cement mortarwith nanophase materials. Cement and Concrete Research 2004;34: 435–438.12.Nazari A, Riahi S, Riahi S, Shamekhi SF andKhademno. Benefits of Fe2O3nanoparticles in concrete mixing matrix . Journal of American Science. 2010;6:102-106.13.Nazari A, Riahi S, Riahi S, Shamekhi SF andKhademno. The effects of incorporation Fe2O3 nanoparticles on tensile and flexural strength of concrete. Journal of American Science. 2010;6: 90-93.14.ASTM C150. Standard Specification forPortland Cement. American Society for Testing and Materials;2005.15.ASTM C33. Standard Specification for ConcreteAggregates. American Society for Testing and Materials;2007. 16.ASTM C109 / C109M. Standard Test Methodfor Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens). American Society for Testing and Materials;2008.17.ASTM C190. Method of Test for TensileStrength of Hydraulic Cement Mortars.American Society for Testing and Materials;1985.18.Arefi MR, Mollaahmadi E, Abdollahi Nejand B,Fattah M, High performance self -cleaning cement mortar composite and coats prepared by TiO2 nanoparticles. Submited in Journal of Materials in Civil Engineering..19.Li H, Zhang MH, Ou JP. Flexural fatigueperformance of concrete containing nano-particles for pavement. Int J Fatigue 2007;29: 1292–1301.11/20/2011。