Hydrothermal Reactions between Calcium Hydroxide and Amorphous Silica.
2-水化学成分和水化学指标
– Thus ions like Cl−, I−, Na+, and K+ are only found in one ionic form in water.
Hydrolysis-Monovalent ions
– However, there are some exceptions. F− tends to attract H+, especially at low pH where an abundance of H+ ions are present in the bulk solution. Why does F− hydrolyze and not Cl−? – F− has a smaller crystallographic radius (晶体学半径, 而非水合半径: hydrated radius) and a higher charge density at its surface and so is more likely to attract a hydrogen ion. The hydrolysis reaction (written in reverse) is merely an acid dissociation reaction:
Hydrolysis-Monovalent ions
– Monovalent ions rarely hydrolyze solution because the single positive negative charge is insufficient dislodge or attract hydrogen ions to from the bulk solution. in or to or
Ion Hydrolysis
水化硅酸钙的制备及其吸附性能
水化硅酸钙的制备及其吸附性能张宏森;郭语桐;蒋保江;王君【摘要】为获得性能优异的吸附材料,以工业废物白泥和油页岩灰为原料制备水化硅酸钙,利用X射线粉末衍射仪和透射电子显微镜等分析其结构和形貌,并通过重金属吸附实验分析其吸附性能。
结果表明:水化硅酸钙具有薄片相互交错的网状结构,最佳合成条件为反应温度25℃、钙硅比1.5。
水化硅酸钙吸附过程符合Langmuir 吸附热力学模型。
它对U~(6+)、Pb~(2+)、Cd~(2+)、Cr~(3+)四种重金属离子的最大吸附容量均大于200 mg/g,去除率均大于86%。
其优异的吸附性能主要源于薄片层结构和离子交换机制。
该研究为溶液中重金属去除提供了廉价、高效的吸附材料,对于白泥和油页岩灰资源化利用亦具有推动作用。
【期刊名称】《黑龙江科技大学学报》【年(卷),期】2018(028)001【总页数】5页(P65-69)【关键词】水化硅酸钙;制备;吸附性能;油页岩灰;白泥【作者】张宏森;郭语桐;蒋保江;王君【作者单位】[1]黑龙江科技大学环境与化工学院,哈尔滨150022;[1]黑龙江科技大学环境与化工学院,哈尔滨150022;[2]黑龙江大学化学化工与材料学院,哈尔滨150086;[3]哈尔滨工程大学材料与化工学院,哈尔滨150001;【正文语种】中文【中图分类】TQ050.430 引言油页岩灰是油页岩加工利用过程中最主要的工业废物,主要成分是SiO2和金属氧化物,该产物数量巨大,长期堆放不仅占用大量的土地,而且会造成严重的环境污染[1]。
白泥是造纸生产过程中产生的主要工业废物,主要成分为CaCO3、CaSO4、CaCl2等钙盐,呈强碱性,每生产1 t粗浆要产生近0.5 t白泥,数量巨大,也会造成严重的环境影响 [2]。
目前,上述两种工业废物的资源化利用一直备受关注,学者们亦开展了大量研究工作。
Gao Guimei等[3-4]以油页岩灰或白泥为原料制备了二氧化硅微球、氧化铝、文石型碳酸钙等产品,处理工业废物的同时实现了资源化利用。
羟基磷灰石的制备与应用
羟基磷灰石的制备与应用孙镇镇/文【摘要】羟基磷灰石是自然界中生物骨组织的构成要素,其微孔是由天然孔道结构形成,具有较强的表面吸附性和离子交换性,是一种具有良好应用前景的无机生物矿物材料,在生物医用材料、环境功能材料、湿敏半导体材料、催化剂载体以及抗菌功能材料等方面都有广泛的应用。
本文首先简单介绍了羟基磷灰石的基本性能,重点阐述了羟基磷灰石的制备方法,最后对其应用进行了阐述。
【关键词】羟基磷灰石;性能;制备;应用羟基磷灰石 (hydroxyapatite, HAP),化学式为Ca10(PO4)6(OH)2,是一种微溶于水的磷酸钙盐,属于六方晶系。
HAP 的结构可以描述为磷氧四面体基团的紧密结合体,图1为HAP 的晶体结构图[1]。
从图1中可以看到,P5+位于四面体的中心,并且其顶部被4个 O 原子占据。
Ca2+则被磷氧四面体所包围,在晶胞中占有2个独立的位置 Ca(I) 和 Ca(II),从而形成 2 种直径不同、互不相连的通道。
由于 HAP 结构中存在2个不同的钙位点,所以可以通过对钙位点的特定修饰来调节 HAP 的特性。
图1 羟基磷灰石的晶体结构羟基磷灰石的密度为3.156g/ cm3,熔点为1650℃,溶度积为(6.3±2.1)×10-59,晶体折射率为1.64-1.65。
其在水中溶解度约0.4 ppm,呈弱碱性,pH为7-9。
在人体骨骼中,羟基磷灰石大约占总质量的90%,其余10%为碳酸钙和其他无机盐[2-4]。
羟基磷灰石是自然界中生物骨组织的构成要素,其微孔是由天然孔道结构形成,具有较强的表面吸附性和离子交换性,随着科技和医学的不断前行,为了更大程度地发挥其性质,人工合成的羟基磷灰石也变得越来越多,它可以凭借自身的生物相容性、生物活性、骨传导性在骨治疗上发挥重要的作用。
过去的二十年中,羟基磷灰石在骨和牙齿植入、吸附重金属等领域均有报道。
但在实际应用中,不容忽视的是羟基磷灰石自身存在的机械性能不佳、使用中容易团聚、使用后回收困难等缺点,这些缺点极大的限制了它的广泛应用。
醇水混合溶剂中制备钨酸铋中空纳米结构
醇水混合溶剂中制备钨酸铋中空纳米结构陈磊;吴大雄;朱海涛【摘要】Bi2WO6 nano-structures were synthesized in ethano-water mixed solvent with Bi(NO3)3 and Na2WO4 as reactants. Bi2 WO6 hollow nano-structures can be prepared through solvothermal process by adjusting the ratio of ethanol to water, reaction temperature and reaction time. The results indicated that Bi2WO6 hollow nano-spheres with 30 - 50 nm in diameter and 10 nm in thickness could be synthesized when the ratio of ethanol to water was 10:1, reaction temperature 100 ℃, and rea ction time was 12 h.%以硝酸铋和钨酸钠为反应物,在乙醇-水混合溶剂体系中反应生成钨酸铋纳米结构.通过调整乙醇和水的比例、反应温度、反应时间等参数,在溶剂热条件下可以直接生成钨酸铋中空纳米结构.实验结果表明,当醇水体积比为10∶1,溶剂热温度为100℃,反应时间为12 h时,制备的Bi2WO6纳米空心球粒度均匀,直径在30~50 nm,壳的厚度在10 nm左右.【期刊名称】《青岛科技大学学报(自然科学版)》【年(卷),期】2012(033)001【总页数】4页(P9-12)【关键词】钨酸铋;中空纳米结构;混合溶剂【作者】陈磊;吴大雄;朱海涛【作者单位】青岛科技大学材料科学与工程学院,山东青岛266042;青岛科技大学材料科学与工程学院,山东青岛266042;青岛科技大学材料科学与工程学院,山东青岛266042【正文语种】中文【中图分类】TB321中空纳米结构是指内部空腔及壁厚都在纳米尺度范围内的壳层结构。
脱硫石膏制备γ-CaSO_(4)晶须及Ⅱ-CaSO_(4)晶须
Washing FGD gypsum
Middle layer Settlement stratification Drying
Washed gypsum
Hydrothermal reactiLeabharlann nBoiling water
MgCl2 HCl H2O
II-CaSO4 whisker
600 ℃ Roasting γ-CaSO4 whisker
文献标志码:A
DOI:10.3969/j.issn.1003-9015.2021.03.018
Preparation of γ-CaSO4 and II-CaSO4 whiskers using FGD gypsum
MA Wen-jing1, CHEN Xue-qing1, GAO Li-li1, LI Yun1, GUO Hong-fei1, LI Zhi-shui2, CAO Ji-lin1 (1. Hebei Provincial Key Lab of Green Chemical Technology and High Efficient Energy Saving, School of Chemical
1前 言
脱硫石膏(flue gas desulfurization gypsum,FGD gypsum)是工业烟气湿法脱硫的副产物,主要成分为 二水硫酸钙(CaSO4·2H2O),还含有粉煤灰、铁硅氧化物、碳酸钙、亚硫酸钙、钾镁硫酸盐等杂质。由于
收稿日期:2020-06-04;修订日期:2020-09-21。 基金项目:河北省自然科学基金(B2018202330);河北省高等学校科学技术研究项目(ZD2019042,QN2019012);天津市科技局企业科技特派员项目。 作者简介:马文静(1996-),女,河北保定人,河北工业大学硕士生。通信联系人:李雲,E-mail:liyun@
水热反应条件对BaTiO3纳米晶形成的影响及其原子尺度表面结构
344电子显微学报J.Chin.Eleetr.Microsc.Soc第28卷4000EX型)在原子尺度研究BT纳米粉体的表面结构。
利用GatanCCD(Model794)记录TEM、HRTEM和选区电子衍射花样(SAED)。
裹1水热合成BaTi03纳米晶体所用的原料和反应介质Table1St*rangmaterialsandreadivemⅨliausedforhydrothermalsynthesisofBaTiOjnanocrystalsNo.竺竺竺!竺[Ba,_ri]一R。
帆media.————”~一艮∞6”BapreetmⅡTiplec㈣molⅡratio’volumeratioofl:1,EG:ethyleneglycol2结果与讨论2.1BT纳米晶的尺寸和形貌SEM和TEM的结果表明BT纳米晶的尺寸和形貌不仅与水热反应前驱体的Ba/Ti摩尔比有关,而且与水热反应介质也相关。
首先讨论水热反应前驱体的B“Ti摩尔比对BT纳米晶的尺寸和形貌的影响。
图1为采用不同Ba/Ti摩尔比的前驱体水热合成BT纳米晶体的TEM照片。
从图1a和lb可以看到,在前驱体的Ba/Ti摩尔比较小时,BT纳米晶呈现多面体形状,而不是球状;纳米晶尺寸分布呈现双峰分布(大的和小的多面体形状)。
随着前驱体Ba/Ti摩尔比的增加,BT纳米晶的形貌逐渐变为长方体,立方体,晶粒的平均尺寸也增大(图1a一1d中的晶粒平均尺寸分别为170,180,190,260nm)。
这种现图l采用不同Ba/Ti摩尔比的前驱体水热合成BaTi03纳米晶体的TEM照片(Bar=200nm)。
样品a:BTl(I:1);b:81"2(2:1);c:BT3(3:1);d:BT4(4:1)Fig.1TEMimagesofthehydrothermalBaTi03(BT)nanocrystalssynthesizedatdifferentBa/Timolarrati06iIItheprecursors(Bar--200ilnl).a.-BTI(1:1);b:BT2(2:1);c:BT3(3:1);d:B'r4(4:1)第4期朱信华等:水热反应条件对BaTiO,纳米晶形成的影响及其原子尺度表面结构345图2不同水热反应介质条件下合成BaTiq纳米晶体的SEM(a—e)和TEM(d—f)照片(前驱体的B“Ti摩尔比固定为3:1)。
水热合成制备水化硅酸钙-聚氨酯纳米复合材料的结构分析
Key words: calcium silicate hydrate polyurethane nanocomposites; hydrothermal synthesis; calcium silicon ratio; micro
3566
硅 酸 盐 通 报
水泥混凝土
第 40 卷
艺。 相反,Shen 等 [8] 、Kanchanason 等 [9] 和 Plank 等 [10] 研究表明有机聚合物不能嵌入 C-S-H 层间,认为聚合
物被吸附在 C-S-H 的表面或孔隙中,从而影响其结构。 此外,Khoshnazar 等 [11-12] 提出,聚合物可以部分嵌入
C-S-H 夹层中,剩余部分吸附在表面或孔隙中。 聚氨酯( PU) 是一种综合性能优异的高分子材料,它已成功
地用于制备插层黏土基纳米复合材料,并可以改善复合材料的性能 [13-14] 。 至今有关 PU 与 C-S-H 相互作用
的研究很少,为了更加有效地控制纳米复合材料的性能,需要更深入地研究有机和无机复合材料的相互作用
聚合物与 C-S-H 结构的相互作用机理仍然存在争议。 Pelisser 等 [4] 、Wang 等 [5] 和 Zhou 等 [6-7] 认为,聚合物可
以嵌入 C-S-H 层间,且表明插层的成功取决于合适的聚合物类型和浓度、主体 C-S-H 的钙硅比以及合成工
收稿日期:2021-04-28;修订日期:2021-06-15
形貌,这表明水热法可以合成 C-S-H 纳米复合材料。 不同钙硅比 C-S-H 的微观结构有较大的差异:钙硅比为
石灰乳法制备四氧化三锰步骤
锰含量可达 71.27%。
关键词:石灰乳;碱式氯化锰;四氧化三锰;水热法
中图分类号:TF111.31
文献标志码:A
Preparation of manganese tetroxide with lime milk
YANG Zhichao1, FENG Yali1, LI Haoran2, LIU Xinwei1, WANG Weida1, ZHOU Yuzhao1, TENG Qing1
第 23 卷第 11 期
中国有色金属学报
Vol.23 No.11
The Chinese Journal of Nonferrous Metals
文章编号:10040609(2013)11325406
石灰乳法制备四氧化三锰
2013 年 11 月 Nov. 2013
杨志超 1,冯雅丽 1,李浩然 2,刘欣伟 1,王维大 1,周宇照 1,滕 青 1
(1. 北京科技大学 土木与环境工程学院,北京 100083; 2. 中国科学院 过程工程研究所,生化工程国家重点实验室,北京 100190)
摘 要:研究氯化锰与石灰乳制备四氧化三锰,并采用正交实验考察石灰乳浓度为 1 mol/L 时,Mn2+浓度、反应
水热合成硅酸盐骨料及其自保温砌块制备
硅、 成 以
电石渣 的活性 成
作用的 , 电石渣
的活性CaO
的。
,试验电石渣
以活性CaO进行 。电石渣 = 活性
CaO含量/所用电石渣中活性CaO含量"100%。本文
所用电石渣 的活性CaO 为58.56%,混合料活
性为 12%,电石渣用量为 12%/58.56%"100%=20.5%。
水热 的 性, 合试验
知,在进行配制时,以20%作为电石渣基 ,整
粉煤灰
混合料用
合 , 试验
见表3。 2试验结果与分析
按照GB/T 17431.1—2010《轻集料及其试验方
1部分:轻集料泸进行性能 试, 4。
4 , 水热合成硅酸盐骨料的 水 为
6.14%&8.25%,堆积密度为 660&720 kg/m3,煮沸质
表3水热合成骨料的试验配合比
Key words: Hydrothermal synthesis; Silicate aggregate; Cylinder compression strength; Self-insulating block
0 前言
人工合成骨料具有密度小、筒压强度高、吸水 率低、抗冻性能好等优点,其制品广泛应用于建筑 结构、桥梁、隔热保温、吸音隔音等工程[1-2]o
[14]
得,轻集料
混凝土砌块的抗压强度为5.8 MPa,
GB/T
15229—2011中MU5.0级强度要求。
3.2自保温砌块的主要
性 测定
配合
自保温砌块,
砌块
试生 产, 砌块 为 390 mmx250 mmx
190 mm,产品见图1。依据GB/T 4111—2013进行砌
水化硅酸钙的合成及其组成、结构与形貌
was investigated by the techniques of X—ray
diffraction(XRD),Infrared spectrum
(取),Nuclear
magnetic resonance(NMR),Scanning electron microscope(SEM),
并向社会公众提供信息服务。 (保密的论文在解密后应遵守此规定)
签名:劫互幽导师签名:昌棒矿日期:矽㈣≮。\
武汉理工大学硕士学位论文
第1章绪论
1.1水化硅酸钙的重要性
在胶凝材料中,水泥尤其是硅酸盐水泥占有突出地位。它是基础建设的主
要原材料之一,广泛应用于工业、农业、国防、交通、城市建设、水力以及海
洋开发等工程建设。同时,水泥制品在代替钢材、木材等方面也越来越显示出
武汉理工大学硕士学位论文
摘
要
水化硅酸钙(简称C.S.H)是波特兰水泥水化的最主要水化产物,也是水
泥基复合材料最主要的强度来源。C.S.H组成与结构的研究对理解、调节与控 制水泥基复合材料的力学性能与化学稳定性具有重要意义。本文围绕C.S.H的 合成及其组成、结构与形貌开展了系统的研究,主要工作和取得的重要成果有:
controlling
the
mechanical properties
chemical
cement—based
on
composite
materials.This paper carried
of C—S—H,its
systematic study,which focused
the synthesis
work
tetrahedron structure of C.S.H were DP
氢氧化钾碱蚀法制备多孔MgAl_氢氧化物及其二氧化碳吸附性能
表面技术第52卷第11期氢氧化钾碱蚀法制备多孔MgAl氢氧化物及其二氧化碳吸附性能高婉,骞蒙,冯艳艳*,李彦杰(桂林理工大学 化学与生物工程学院,广西 桂林 541004)摘要:目的类水滑石化合物用于CO2吸附时存在分散性差和有效比表面积低的问题。
方法以硝酸镁和硝酸铝为金属盐前驱体,以尿素为沉淀剂,采用水热法合成具有层状结构的MgAl水滑石,之后利用铝物种的两性性质,通过氢氧化钾碱蚀处理MgAl水滑石脱除部分铝物种以形成孔道,从而获得多孔MgAl氢氧化物并用于二氧化碳的吸附。
借助X射线衍射、扫描电镜、低温氮气吸附/脱附、红外分析等研究碱蚀时间对所得MgAl氢氧化物结构形貌的影响。
之后,采用热重分析仪测试样品的二氧化碳吸附性能,并且分别采用一阶动力学模型、伪二阶动力学模型对吸附数据进行拟合。
结果与未碱蚀样品比较,当碱蚀时间为12 h时,样品LDH-12的比表面积和孔体积都有所增加,其中比表面积由8.8 m2/g变为16.6 m2/g,这有利于吸附活性位点的暴露;样品LDH-12对二氧化碳有着较优的吸附性能,其吸附容量为19.6 mg/g。
结论碱蚀处理对样品的形貌结构及吸附性能有着很大的影响。
适宜的碱蚀时间有利于样品孔结构的进一步发育,使得更多的吸附活性位暴露,从而较大程度地提高其对二氧化碳的吸附能力。
关键词:MgAl氢氧化物;二氧化碳吸附;碱蚀;比表面积;活性位;吸附动力学模型中图分类号:TQ028;TG174 文献标识码:A 文章编号:1001-3660(2023)11-0386-08DOI:10.16490/ki.issn.1001-3660.2023.11.033Adsorption of CO2 on Porous MgAl Hydroxides Prepared byAlkaline Etching of KOH SolutionGAO Wan, QIAN Meng, FENG Yan-yan*, LI Yan-jie(Department of Chemistry and Bioengineering, Guilin University of Technology, Guangxi Guilin 541004, China)ABSTRACT: A large amount of CO2 has caused adverse effects on people's life, and it is imperative to reduce the concentration of CO2 in the atmosphere. As an effective way to capture CO2, hydrotalcite-like compounds have problems of poor dispersion and low effective specific surface area for use in CO2 adsorption. To address these problems, MgAl layered double hydroxides (LDHs) were firstly prepared via one-pot hydrothermal method with Mg(NO3)2·6H2O and Al(NO3)3·9H2O as precursors and urea as precipitator. Then, taking advantage of the amphoteric nature of Al species, MgAl hydroxides were treated by alkaline收稿日期:2022-09-16;修订日期:2023-07-15Received:2022-09-16;Revised:2023-07-15基金项目:国家自然科学基金(21606058);广西自然科学基金(2017GXNSFBA198193)Fund:Supported by the National Natural Science Foundation of China (21606058) and the Natural Science Foundation of Guangxi (2017GXNSFBA198193)引文格式:高婉, 骞蒙, 冯艳艳, 等. 氢氧化钾碱蚀法制备多孔MgAl氢氧化物及其二氧化碳吸附性能[J]. 表面技术, 2023, 52(11): 386- 393.GAO Wan, QIAN Meng, FENG Yan-yan, et al. Adsorption of CO2 on Porous MgAl Hydroxides Prepared by Alkaline Etching of KOH Solution[J]. Surface Technology, 2023, 52(11): 386-393.*通信作者(Corresponding author)第52卷第11期高婉,等:氢氧化钾碱蚀法制备多孔MgAl氢氧化物及其二氧化碳吸附性能·387·etching of KOH solution to remove Al species to obtain porous MgAl hydroxides with high CO2 adsorption capacity. The morphologies and structures of porous MgAl hydroxides with various alkaline etching times were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption/desorption and Fourier transform infrared spectroscopy (FT-IR), respectively. The characterization results showed that with alkaline etching, the characteristic peaks at 2θ of 23.6°,39.7° and 47.1° changed from narrow and sharp single peaks to double peaks. The removal of Al species led to the destructionof the characteristic peaks of MgAl hydroxides, along with the appearance of characteristic peaks of Mg(OH)2 and Al(OH)3.With the alkaline etching time increased, more Al species were removed, and the characteristic peaks of Al(OH)3 became weaker, while the characteristic peaks of Mg(OH)2 became stronger. Compared with the sample LDH-0 without alkaline etching, with the alkaline etching time of 12 h, the specific surface area and pore volume of the sample LDH-12 increased, and the specific surface area of LDH-12 changed from 8.8 m2/g to 16.6 m2/g, which was conducive to the exposure of adsorption active sites. In addition, after the alkaline etching treatment, the modified samples still maintained the regular hexagonal morphology, but the layer structure of the samples became thinner with the rougher surface, indicating that the alkaline etching could remove some Al species from the sample. With the prolongation of the alkaline etching time, the sample LDH-24 presented a regular hexagonal ring, and part of the structure began to be destroyed. CO2 adsorption performances of the samples were conducted by a thermogravimetric analyzer, and the adsorption data were fitted by the first-order and pseudo-second-order models. Obviously, the adsorption of the alkaline-etched adsorbents was significantly improved, and the sample LDH-12 possessed the superior CO2 adsorption capacity of 19.6 mg/g. As the alkaline etching time further increased, the CO2 adsorption capacity of LDH-18 declined. Additionally, the fitting coefficient of the pseudo-second-order model was higher than that of the first-order model, which suggested the existence of chemical adsorption. These above results show that the alkaline etching treatment had an obvious effect on the morphology and structure of the samples, and the adsorption performance of the alkaline-etched samples are greatly improved. Moreover, an appropriate alkaline etching time could advance the development of pore structure of the adsorbent and facilitate the contact between CO2 molecules and the active sites over the adsorbent, thus promoting CO2 capture to a large extent. Consequently, this work will be beneficial to solve the problems in traditional hydrotalcite-like compounds for CO2 adsorption and have great potential and important academic significance for fabricating high-efficient CO2 adsorbent materials.KEY WORDS: MgAl hydroxides; CO2 adsorption; alkaline etching; specific surface area; active sites; adsorption kinetic models随着社会的快速发展,大气中CO2浓度不断升高,到如今其导致的温室效应,已变得尤为明显,若不加以控制,将导致海平面不断上升,威胁人类的发展[1-2]。
第九章 水热合成方法
低温、等压、溶液条件,有利于生长极少缺 陷、取向好、完美的晶体,且合成产物结晶 度高以及易于控制产物晶体的粒度。 易于调节水热与溶剂热条件下的环境气氛, 有利于低价态、中间价态与特殊价态化合物 的生成,并能均匀地进行掺杂。
反应的基本类型基本类型
1.合成反应 通过数种组分在水热或溶剂热条
件下直接化合或经中间态发生化合反应。利用 此类反应可合成各种多晶或单晶材料。 Nd2O3 + H3PO4 → NdP5O14
国内外学者的研究工作很多。通过水热反应 制备无机/有机固体杂化材料显示出诸多优越性。 吉林大学冯守华教授及其研究小组从简单的无机 原料及有机胺出发,于160℃水热条件下合成出 三维网络结构化合物Cd(C3N2H11)2V8O20。该化合 物是由无机层 {V8O20}4 - 与过渡金属络离子 [Cd(C3N2H11)2]4+构成。{V8O20}4 -无机层由相同数 目的VO4四面体、VO5四角锥以共顶点和共边方式 相互连接形成二维层状结构。[Cd(C3N2H11)2]4+ 络离子以共价键形式支撑于无机层间,形成敞开 的三维网络结构。
CaO· Al2O3 + H3PO4 → Ca5(PO4)3OH + AlPO4
La2O3 + Fe2O3 + SrCl2 → (La, Sr) FeO3 FeTiO3 + KOH → K2O· nTiO2 n=4, 6。
2. 水热处理反应 利用水热与溶剂热条件 处理一般晶体而得到具有特定性能晶体的反 应。例如: 人工氟石棉→人工氟云母 3. 转晶反应 利用水热与溶剂热条件下物 质热力学和动力学稳定性差异进行的反应。 例如: 长石→高岭石; 橄榄石→蛇纹石; NaA沸石→NaS沸石。
不同硅质原料水热合成水化硅酸钙物相及其反应效率的研究
第42卷第3期2023年3月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.42㊀No.3March,2023不同硅质原料水热合成水化硅酸钙物相及其反应效率的研究刘㊀志1,任子杰1,2,高惠民1,2,王㊀康1,宋昱晗1,2,管俊芳1,2(1.武汉理工大学资源与环境学院,武汉㊀430070;2.矿物资源与环境湖北省重点实验室,武汉㊀430070)摘要:为探究不同硅质原料对水热合成水化硅酸钙物相的影响,研究了温度和硅钙比对产物的影响㊂采用X 射线衍射(XRD)分析了水化硅酸钙物相,并探究了不同硅质原料与Ca(OH)2的反应效率㊂结果表明,不同硅质原料与Ca(OH)2的反应效率由高到低依次为硅藻土㊁石英㊁珍珠岩;在硅藻土-石灰体系中,硅藻土中非晶态二氧化硅的Si O 更易被破坏,具有不稳定性,致使硅藻土反应效率更高㊂在石英-石灰体系中,随着钙硅比的提高,空气中的CO 2参与反应,生成碳硅钙石与片柱钙石,且托贝莫来石与硬硅钙石会逐渐消失,通过合理调控硅钙比和水热温度可有效地控制反应产物,这对于不同硅质原料的选择㊁水热合成水化硅酸钙中产物的控制及水热合成水化硅酸钙应用领域具有重大意义㊂关键词:水化硅酸钙;石英;硅藻土;珍珠岩;硅钙比;温度中图分类号:TQ172.1㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2023)03-0854-07Hydrothermal Synthesis of Calcium Silicate Hydrate from Different Siliceous Materials and Its Reaction EfficiencyLIU Zhi 1,REN Zijie 1,2,GAO Huimin 1,2,WANG Kang 1,SONG Yuhan 1,2,GUAN Junfang 1,2(1.School of Resources and Environmental Engineering,Wuhan University of Technology,Wuhan 430070,China;2.Hubei Key Laboratory of Mineral Resources Processing and Environment,Wuhan 430070,China)Abstract :In order to explore the effects of different siliceous materials on the phase of calcium silicate hydrate synthesized by hydrothermal method,the effects of temperature and silicon-to-calcium ratio on the product were studied.The phase of calcium silicate hydrate was analyzed by X-ray diffraction (XRD),and the reaction efficiency of different siliceous raw materials with Ca(OH)2was investigated.The results show that the reaction efficiency of different siliceous raw materials with Ca (OH)2from high to low is diatomite,quartz and perlite.In the diatomite-lime system,the amorphous silicon dioxide Si O in diatomite is easier to be destroyed,and it has instability,resulting in higher reaction efficiency of diatomite.In the quartz-lime system,with the increase of silicon-to-calcium ratio,CO 2in the air can participate in the reaction to generate tilleyite and scawtite,while tobermorite and xonotlite gradually disappear.The reaction product can be effectively controlled by reasonably adjusting the silicon-to-calcium ratio and hydrothermal temperature.This is of great significance to the selection of different siliceous raw materials,the control of products of calcium silicate hydrate and the application field of calcium silicate hydrate synthesized by hydrothermal method.Key words :calcium silicate hydrate;quartz;diatomite;perlite;silicon-to-calcium ratio;temperature收稿日期:2022-10-07;修订日期:2022-11-25基金项目:科技部重点研发计划(2020YFC1909605)作者简介:刘㊀志(1997 ),男,硕士研究生㊂主要从事非金属矿提纯的研究㊂E-mail:1046177354@通信作者:任子杰,博士,副教授㊂E-mail:renzijie@ 0㊀引㊀言硅酸钙是由不同比例的氧化钙(CaO)和二氧化硅(SiO 2)组成的化合物[1],其结构范围广,从弱结晶态到近乎无定形均有,具有可变的化学计量㊁化学成分和性质[2-3],且具有轻质㊁耐火㊁导热系数低㊁强度高㊁物理第3期刘㊀志等:不同硅质原料水热合成水化硅酸钙物相及其反应效率的研究855㊀吸水率高等特点[4],广泛应用于建筑㊁造纸㊁橡胶㊁保温材料等领域[5-8]㊂在建筑行业中,硅酸钙作为新型建筑材料正逐步取代石膏板和石棉水泥[9]㊂水化硅酸钙(C-S-H)体系复杂多变,有30多种稳定相[10],且不同的相在胶体域中的范德华力不同,所以C-S-H 相的类型对最终产物的强度发展起着至关重要的作用[11]㊂Ogur 等[12]发现采用水热合成的硬硅钙石作为原材料可增大3D 打印悬浮支架的孔隙率,并使强度达到0.9MPa㊂Jiang 等[13]利用硅灰水化合成的C-S-H 凝胶填充水泥间孔隙,提高了材料强度㊂Chen 等[5]在制备硅酸钙板的过程中发现,托贝莫来石的结晶度越高,板材的性能越好㊂Zhan 等[14]研究发现网状的C-S-H 有利于提高硅酸钙板的吸水率,且可降低导热系数㊂生产C-S-H 所采用的SiO 2原料多样,如石英[8]㊁纳米SiO 2[15]㊁气态SiO 2[16]㊁白炭黑[17]等㊂矿物作为硅质原料具有储量大㊁来源稳定㊁价格低廉等优点,但用其作原料合成C-S-H 的研究较少㊂然而矿物成分复杂,对水热合成C-S-H 时影响因素较多,因此探究不同矿物作硅质原料对合成C-S-H 尤为重要㊂本文通过水热合成法[18]探究了在石英㊁硅藻土㊁珍珠岩与Ca(OH)2生成C-S-H 过程中温度和钙硅比(C /S,摩尔比)对生成硅酸钙物相的影响,并对比了其反应效率,为合成C-S-H 中硅质原料的选择提供了依据和参考㊂1㊀实㊀验1.1㊀试验原料试验选取的硅质原料分别为石英㊁硅藻土㊁珍珠岩,均为非黏土类矿物,具有来源广泛㊁SiO 2含量差异较大等特点;试验选取的钙质原料为消石灰;石英砂取自内蒙古某公司,粒度小于74μm;硅藻土取自吉林长白某公司,粒度均小于74μm;珍珠岩为市售产品,粒度小于74μm㊂所用消石灰由内蒙古某公司提供㊂试验原料的物相组成见图1㊂图1㊀石英㊁硅藻土㊁珍珠岩与消石灰的XRD 谱Fig.1㊀XRD patterns of quartz,diatomite,perlite and slaked lime 通过X 射线荧光分析其化学成分,石英㊁硅藻土及珍珠岩的化学成分见表1㊂EDTA 容量法[19]测定消石856㊀水泥混凝土硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷灰中有效CaO 质量分数为70%,即Ca(OH)2含量为92.5%㊂表1㊀硅藻土和珍珠岩的化学成分Table 1㊀Chemical composition of diatomite and pearliteCompositionMassfraction /%Na 2O MgO Al 2O 3SiO 2K 2O CaO TiO 2Fe 2O 3Loss on ignition Quartz 0.020.010.1899.590.05 0.020.13Diatomite 0.210.36 3.3486.430.420.230.18 1.017.77Perlite 2.910.2713.271.814.750.910.090.625.24图2㊀硅质原料粒度组成Fig.2㊀Particle size composition of siliceous raw materials1.2㊀试验过程与试验装置使用电子天平称取设定质量比的石英㊁硅藻土和珍珠岩,将其与消石灰混合后用研钵研磨30min 至混匀㊂按固液质量比为2ʒ5向物料中加入自来水,放入水热釜中㊂将水热釜放入烘箱中反应8h,待冷却至室温后取出水热釜中物料,在105ħ环境下烘至恒重后,使用单头研磨机将物料研磨,并采用标准筛筛分至74μm 下制样检测,采用BT-9300S 型激光粒度分析仪进行测试分析,其粒度组成如图2所示㊂设定试验温度分别为140㊁150㊁160㊁170㊁180㊁190ħ㊂不同硅质原料的硅钙摩尔比(C /S)见表2㊂表2㊀不同硅质原料的硅钙比Table 2㊀C /S ratio of different siliceous raw materialsRaw materialC /S ratio Quartz 0.680.97 1.26 1.55Diatomite 0.670.90 1.12 1.34Perlite 0.540.81 1.07 1.352㊀结果与讨论2.1㊀石英砂与Ca (OH )2反应2.1.1㊀温度对反应产物的影响将石英和Ca(OH)2按照C /S 比为0.97配制后,在不同温度下水热合成的硅酸钙XRD 谱如图3(a)所示㊂由图3(a)可知:在140ħ温度下,石英砂与Ca(OH)2已经发生了反应,生成了托贝莫来石(Ca 5Si 6O 16(OH)2㊃4H 2O)和弱结晶态的Ⅰ型水化硅酸钙(C-S-H(Ⅰ)),还有少量石英和Ca(OH)2未发生反应;在150ħ下,石英和Ca(OH)2的衍射峰强度进一步减小,托贝莫来石和C-S-H(Ⅰ)的衍射峰强度越来越强,说明在相同水热时间下,托贝莫来石和C-S-H(Ⅰ)在150ħ的水热环境下比在140ħ时生长得更快;当水热温度高于150ħ后,随着温度的升高,托贝莫来石的衍射峰强度呈减弱趋势,硬硅钙石(Ca 6Si 6O 17(OH)2)的衍射峰强度越来越强,水热产物更倾向于生成硬硅钙石[20],说明温度的升高可以促进反应的进行及晶体的生长㊂同时,也说明硬硅钙石结晶温度高于托贝莫来石,且受温度影响很大,在150~170ħ,温度越高,其结晶度越高,也更加稳定㊂2.1.2㊀C /S 比对反应产物的影响在160ħ水热环境下,石英和Ca(OH)2按照不同C /S 比水热合成的产物XRD 谱如3(b)所示㊂可知,当C /S 比为0.68时,水热产物中只有石英和托贝莫来石相㊂石英相的存在说明石英并未完全参与反应,托贝莫来石相的衍射峰较为尖锐,结晶良好㊂增加C /S 比为0.97后,托贝莫来石衍射峰强度开始减弱,硬硅钙石相开始生成㊂继续增加C /S 比到1.26,托贝莫来石的衍射峰强度进一步减弱,硬硅钙石的衍射峰消失,第3期刘㊀志等:不同硅质原料水热合成水化硅酸钙物相及其反应效率的研究857㊀出现了大量的碳硅钙石(Ca 5Si 2O 7(CO 3)2)㊂碳酸根的存在是因为水热釜中存在CO 2气体参与了反应,继续增加C /S 比到1.55,托贝莫来石和硬硅钙石的衍射峰均未出现,但出现了片柱钙石(Ca 7Si 6O 18CO 3(H 2O))的衍射峰㊂通过XRD 谱分析可知,合理的C /S 比可加快反应,并能有效控制石英砂与Ca(OH)2的反应产物类型㊂图3㊀石英砂与Ca(OH)2在不同的反应温度和C /S 比下反应产物的XRD 谱Fig.3㊀XRD patterns of reaction products of quartz sand and Ca(OH)2at different reaction temperatures and C /S ratio 2.2㊀硅藻土与Ca (OH )2反应2.2.1㊀温度对反应产物的影响将硅藻土与Ca (OH)2按照C /S 比为1.12混合,在不同温度下对反应产物的影响见图4(a)㊂由图4(a)可知:在140ħ下,硅藻土与Ca(OH)2主要反应产物为C-S-H(Ⅰ),同时有少量的托贝莫来石生成;当水热温度提升到160ħ后,C-S-H(Ⅰ)的衍射峰消失,硬硅钙石物相开始生成㊂尽管在160ħ水热温度下生成的托贝莫来石含量较少,但是与其他水热温度下相比,160ħ水热温度下托贝莫来石衍射峰强度较高,其结晶度较好,说明在硅藻土与Ca(OH)2的水热反应体系中,托贝莫来石最佳生成温度为160ħ㊂当水热温度超过170ħ后,反应产物全部为硬硅钙石㊂温度越高,硬硅钙石的衍射峰越尖锐,说明温度越高,硬硅钙石的结晶越好㊂2.2.2㊀C /S 比对反应产物的影响由硅藻土和Ca(OH)2在160ħ水热环境下按照不同C /S 比水热合成的产物XRD 谱如图4(b)所示㊂由图4(b)可知,硅藻土与Ca(OH)2在不同C /S 比下的反应产物差异较大㊂在C /S 比为0.67时,反应产物为弱结晶态的C-S-H(Ⅰ);升高C /S 比至0.90时,反应产物为托贝莫来石和硬硅钙石的混合物;继续升高C /S 比到1.12,反应产物主要为硬硅钙石,并含有少量的托贝莫来石;当C /S 比达到1.34时,反应产物又成为了非晶态的C-S-H(Ⅰ)㊂图4㊀硅藻土与Ca(OH)2在不同的反应温度和C /S 比下反应产物的XRD 谱Fig.4㊀XRD patterns of reaction products diatomite and Ca(OH)2at different reaction temperatures and C /S ratio858㊀水泥混凝土硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷对比图4(b)与图3(b)可知,当硅藻土与Ca(OH)2的C /S 比为0.67时,反应产物为C-S-H(Ⅰ),是因为硅藻土具有较大的比表面积,活性二氧化硅较多,反应速度较快,可迅速将体系中的钙消耗完全,但此时还不足以结晶成为托贝莫来石或硬硅钙石的晶质物相㊂而在石英-石灰反应体系中,石英尚未反应完全,表明硅藻土中的二氧化硅反应效率更高㊂当C /S 比为0.90时,反应产物为托贝莫来石和硬硅钙石的混合物,硬硅钙石的产生可能是因为此时体系中的钙已经过量,在结晶成为托贝莫来石后,剩余的钙离子继续参加反应,生成了硬硅钙石㊂当C /S 比继续增加到1.12时,反应产物中托贝莫来石含量进一步减少,大部分为硬硅钙石,还可以观察到剩余的Ca(OH)2物相,说明体系中Ca(OH)2已经过量,更有利于硬硅钙石的生成㊂继续增加C /S 比到1.34,反应产物中主要物相为C-S-H(Ⅰ),此刻的C-S-H(Ⅰ)中的钙元素的含量一定高于C /S 比为0.67时生成的C-S-H(Ⅰ)中的钙元素含量㊂2.3㊀珍珠岩与Ca (OH )2反应2.3.1㊀温度对反应产物的影响将珍珠岩粉末与Ca (OH)2按照C /S 比为1.35的比例混合,在不同温度下对反应产物的影响见图5(a)㊂由图5(a)可知:在170ħ的水热环境下,珍珠岩与Ca(OH)2未发生反应,大部分Ca(OH)2转化为CaCO 3;当水热温度达到180ħ后,反应产物中出现了托贝莫来石相,而在石英-石灰体系和硅藻土-石灰体系中,在140ħ下产生了托贝莫来石相,说明珍珠岩与Ca(OH)2的反应效率低于另外两种硅质原料;当水热温度达到190ħ后,托贝莫来石衍射峰更加尖锐,说明此时更有利于托贝莫来石的形成㊂由硬硅钙石的化学结构式为Ca 6(Si 6O 17)(OH)2可知,生成硬硅钙石的最佳C /S 比为1㊂在C /S 比为1.35时,140~190ħ水热温度阶段中,珍珠岩与Ca(OH)2的反应产物中未发现有硬硅钙石相的生成,此时的C /S 比要远远大于生成硬硅钙石的理论C /S 比㊂因此,未生成硬硅钙石的原因可能不是C /S 比过低,而是生成硬硅钙石需要的水热温度更高,在190ħ的水热环境下还不足以让珍珠岩与Ca(OH)2反应生成硬硅钙石㊂2.3.2㊀C /S 比对反应产物的影响珍珠岩与Ca(OH)2体系在190ħ水热环境下按照不同C /S 比水热合成的XRD 谱如图5(b)所示㊂由图5(b)可知,随着C /S 比的增加,托贝莫来石的含量减少,结晶度变差,说明在190ħ的水热环境下,C /S 比越低,越有利于生成托贝莫来石,但为了使反应体系中的SiO 2全部参加反应,C /S 比不能过低,应当按照生成托贝莫来石的理论C /S 比0.83来配制珍珠岩与Ca(OH)2㊂当C /S 比为0.81时,反应产物中出现了黑柱石(CaFe 2FeSi 2O 8(OH)),说明珍珠岩的杂质元素Fe 参与了反应,而且C /S 比越高,其衍射峰越尖锐,越有利于黑柱石的形成㊂图5㊀珍珠岩与Ca(OH)2在不同的反应温度和C /S 比下反应产物的XRD 谱Fig.5㊀XRD patterns of reaction products of perlite and Ca(OH)2at different reaction temperatures and C /S ratio 2.4㊀不同硅质材料对比分析分别将石英㊁硅藻土㊁珍珠岩与Ca(OH)2在不同水热温度下反应产物进行对比分析,结果如图6所示㊂由图6可知,在140ħ水热环境下,石英-石灰体系和硅藻土-石灰体系中均产生了托贝莫来石相和C-S-H(I),第3期刘㊀志等:不同硅质原料水热合成水化硅酸钙物相及其反应效率的研究859㊀而珍珠岩-石灰体系在180ħ水热温度下才产生托贝莫来石相,说明硅藻土和石英中SiO 2反应效率高于珍珠岩㊂在不同C /S 比试验条件中,不同类型的硅质原料与Ca(OH)2的反应大不相同㊂在石英-石灰体系中,随着C /S 比的增加,反应釜中的CO 2参与反应,产生了碳硅钙石与片柱钙石㊂在硅藻土-石灰体系中,随着C /S 比的增加,托贝莫来石与硬硅钙石含量逐步减少,反应产物的物相主要是C-S-H(Ⅰ),且此刻的C-S-H(Ⅰ)中的钙元素的含量一定高于C /S 比为0.67时生成的C-S-H(Ⅰ)中的钙元素含量㊂图7为不同硅质原料反应效率对比,可知硅藻土㊁石英㊁珍珠岩与Ca(OH)2的反应效率依次降低㊂SiO 2与Ca(OH)2的反应效率受多方面影响:如SiO 2的粒度越细,其活性越好[21];比表面积越大,其吸附接触面越大,反应活性越好等㊂结合硅藻土㊁石英㊁珍珠岩的矿物特性分析,硅藻土反应效率最高的原因是硅藻土是非晶态的SiO 2,其内部硅氧排列不规则,具有不稳定性[22],Si O 易被钙离子打断,且在粒度相近情况下,比表面积越大其活性越高㊂珍珠岩同属非晶态SiO 2,但SiO 2含量低,且含大量的K 2O㊁Na 2O㊁Al 2O 3等,在不规则的硅氧环中可平衡电价[23],形成稳定的硅酸铝钾㊁硅酸铝钠等,且Al 2O 3的存在会明显阻碍水化硅酸钙的形成,而珍珠岩中Al 2O 3含量最高,因此反应效率最低㊂图6㊀不同硅质原料在不同水热温度下的反应产物Fig.6㊀Reaction products of different siliceous raw materials at different hydrothermaltemperatures 图7㊀不同硅质原料反应效率对比Fig.7㊀Comparison of reaction efficiency of different siliceous raw materials 3㊀结㊀论1)在石英-石灰体系中,随着硅钙比的提高,空气中的CO 2可参与反应,生成碳硅钙石与片柱钙石,且托贝莫来石与硬硅钙石会逐渐消失,因此通过合理地控制硅钙比和水热温度可有效控制其反应产物㊂2)不同硅质原料与Ca(OH)2的反应效率由强到弱依次为硅藻土㊁石英㊁珍珠岩,其主要原因为不同硅质原料中SiO 2含量不同,导致反应效率和产物不同㊂3)在硅藻土㊁石英㊁珍珠岩与Ca(OH)2反应体系中,非晶态的二氧化硅中Si O 更易被破坏,且具有不稳定性,使硅藻土具有更高的反应效率㊂而珍珠岩中具有较低的二氧化硅含量及大量的K 2O㊁Na 2O㊁Al 2O 3在硅氧环中平衡电价,故反应效率较低㊂参考文献[1]㊀GREENBERG S A,CHANG T N.Investigation of the colloidal hydrated calcium silicates.II.Solubility relationships in the calcium oxide-silica-water system at 25ʎ[J].The Journal of Physical Chemistry,1965,69(1):182-188.[2]㊀SHAW S.Dehydration /recrystallization mechanisms,energetics,and kinetics of hydrated calcium silicate minerals:an in situ TGA /DSC andsynchrotron radiation SAXS /WAXS study[J].Chemical Geology,2000,167(1/2):141-159.[3]㊀THOMAS J J.Effects of decalcification on the microstructure and surface area of cement and tricalcium silicate pastes[J].Cement and ConcreteResearch,2004,34(12):2297-2307.[4]㊀CAO Z,CAO Y D,ZHANG J S,et al.Preparation and characterization of high-strength calcium silicate boards from coal-fired industrial solid wastes[J].International Journal of Minerals,Metallurgy,and Materials,2015,22(8):892-900.860㊀水泥混凝土硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷[5]㊀CHEN M X,LU L,WANG S,et al.Investigation on the formation of tobermorite in calcium silicate board and its influence factors underautoclaved curing[J].Construction and Building Materials,2017,143:280-288.[6]㊀刘俊华,张美云,陆赵情,等.粉煤灰提取新型硅酸盐填料在造纸上的应用研究[J].天津造纸,2013,35(4):7-12.LIU J H,ZHANG M Y,LU Z Q,et al.Study on the application of new silicate filler extracted from fly ash in papermaking[J].Tianjin Paper Making,2013,35(4):7-12(in Chinese).[7]㊀刘钦甫,张士龙,孙俊民,等.活性硅酸钙填充丁苯橡胶复合材料性能研究[J].湖南科技大学学报(自然科学版),2013,28(2):95-101.LIU Q F,ZHANG S L,SUN J M,et al.Study on properties of styrene-butadiene rubber filled by active calcium silicate[J].Journal of Hunan University of Science&Technology(Natural Science Edition),2013,28(2):95-101(in Chinese).[8]㊀苟㊀菁,彭小芹,冉㊀鹏,等.掺活性水化硅酸钙隔热涂料的制备及性能研究[J].硅酸盐通报,2019,38(10):3309-3313.GOU J,PENG X Q,RAN P,et al.Preparation and properties research on thermal insulation coatings with active C-S-H[J].Bulletin of the Chinese Ceramic Society,2019,38(10):3309-3313(in Chinese).[9]㊀KRISTANTO L,SUGIHARTO H,AGUS S W D,et al.Calcium silicate board as wall-facade[J].Procedia Engineering,2017,171:679-688.[10]㊀李㊀犇.水化硅酸钙(C-S-H)凝胶的细观力学机理研究[D].哈尔滨:哈尔滨工程大学,2018.LI B.Investigation of the mesco-mechanical properties of calcium-silicate-hydrate[D].Harbin:Harbin Engineering University,2018(in Chinese).[11]㊀SHAW S.Hydrothermal formation of the calcium silicate hydrates,tobermorite(Ca5Si6O16(OH)2㊃4H2O)and xonotlite(Ca6Si6O17(OH)2):an in situ synchrotron study[J].Chemical Geology,2000,167(1/2):129-140.[12]㊀OGUR E,BOTTI R.Synthesis and additive manufacturing of calcium silicate hydrate scaffolds[J].Journal of Materials Research andTechnology,2021,11:1142-1151.[13]㊀JIANG N,WANG C M,WANG Z P,et al.Strength characteristics and microstructure of cement stabilized soft soil admixed with silica fume[J].Materials(Basel,Switzerland),2021,14(8):1929.[14]㊀ZHAN J Y,YANG F H,LI W M,et al.Hydration characteristics and humidity control performance of calcium silicate board prepared from minetailing and diatomite[J].Journal of Wuhan University of Technology-Mater Sci Ed,2020,35(1):147-154.[15]㊀袁㊀琦,何小芳,张利红,等.水热合成制备水化硅酸钙-聚氨酯纳米复合材料的结构分析[J].硅酸盐通报,2021,40(11):3565-3571.YUAN Q,HE X F,ZHANG L H,et al.Structure analysis of calcium silicate hydrate polyurethane nanocomposites prepared by hydrothermal synthesis[J].Bulletin of the Chinese Ceramic Society,2021,40(11):3565-3571(in Chinese).[16]㊀陈友治,钟浩轩,殷伟淞,等.钙硅比对水化硅酸钙结构㊁Zeta电势及减水剂吸附性能的影响分析[J].硅酸盐通报,2020,39(6):1798-1804.CHEN Y Z,ZHONG H X,YIN W S,et al.Effect of calcium-silicon ratio of calcium silicate hydrate on its structure,zeta potential and adsorption capacity of superplasticizer[J].Bulletin of the Chinese Ceramic Society,2020,39(6):1798-1804(in Chinese). [17]㊀曾㊀路,何㊀牟,毛㊀钉.水热合成制度对水化硅酸钙孔结构的影响[J].非金属矿,2017,40(3):10-13.ZENG L,HE M,MAO D.Influence of hydrothermal synthesis conditions on pore structure of calcium silicate hydrates[J].Non-Metallic Mines, 2017,40(3):10-13(in Chinese).[18]㊀CHEN J J.Solubility and structure of calcium silicate hydrate[J].Cement and Concrete Research,2004,34(9):1499-1519.[19]㊀刘惠敏.建筑石灰中CaO,MgO的测定[J].矿物岩石,1999,19(2):96-97.LIU H M.Determination of Cao and mgo in construction lime[J].Journal of Mineralogy and Petrology,1999,19(2):96-97(in Chinese).[20]㊀YANG Z J,KANG D.Crystal transformation of calcium silicate minerals synthesized by calcium silicate slag and silica fume with increase of C/S molar ratio[J].Journal of Materials Research and Technology,2021,15:4185-4192.[21]㊀许晓玲,毛仲佳,王㊀炜.生产轻质硅酸钙板的一些基本条件[J].中国建材科技,1997,6(6):1-9.XU X L,MAO Z J,WANG W.Some basic conditions for producing light calcium silicate board[J].China Building Materials Science& Technology,1997,6(6):1-9(in Chinese).[22]㊀REN Z J,GAO H M.Effects of fluxes on the structure and filtration properties of diatomite filter aids[J].International Journal of MineralProcessing,2014,130:28-33.[23]㊀KUNHI MOHAMED A.An atomistic building block description of C-S-H towards a realistic C-S-H model[J].Cement and Concrete Research,2018,107:221-235.。
氢氧化钙和碳酸氢钠过量与少量反应的离子方程式
氢氧化钙和碳酸氢钠过量与少量反应的离子方程式标题:氢氧化钙和碳酸氢钠反应的离子方程式及其实际应用序言在化学领域中,离子方程式是描述化学反应的重要工具。
本文将探讨氢氧化钙(Ca(OH)2)和碳酸氢钠(NaHCO3)过量与少量反应的离子方程式,并探讨这些反应在日常生活中的实际应用。
一、氢氧化钙和碳酸氢钠过量反应的离子方程式1. 反应描述氢氧化钙和碳酸氢钠过量反应会生成产物,其中主要产物是碳酸钙(CaCO3)和水(H2O)。
2. 离子方程式Ca(OH)2 + 2NaHCO3 → CaCO3 + 2H2O + 2NaOH3. 反应机制与解读在反应中,氢氧化钙中的氢氧根离子(OH-)与碳酸氢钠中的氢氧根离子(HCO3-)发生交换反应,形成水和碳酸钙。
反应也释放出了氢氧根离子和钠离子,使溶液呈碱性。
二、氢氧化钙和碳酸氢钠少量反应的离子方程式1. 反应描述氢氧化钙和碳酸氢钠少量反应会生成产物,主要产物是水(H2O)、二氧化碳(CO2)和碳酸钠(Na2CO3)。
2. 离子方程式Ca(OH)2 + NaHCO3 → Na2CO3 + H2O + CO23. 反应机制与解读在少量反应中,氢氧化钙中的氢氧根离子与碳酸氢钠中的氢氧根离子发生交换反应,形成水、二氧化碳和碳酸钠。
少量反应通常作为酸碱中和反应的一种示例,其中碳酸氢钠充当酸,而氢氧化钙充当碱。
实际应用1. 工业应用氢氧化钙和碳酸氢钠的反应在工业上有广泛的应用。
在水处理中,氢氧化钙可以与含有硬水的碳酸氢钠反应,生成固体的碳酸钙,从而净化水质。
该反应还可用于生产肥料和玻璃等。
2. 医学应用氢氧化钙和碳酸氢钠的反应在医学领域也具有重要意义。
当胃酸过量时,医生可能会建议患者服用一小勺氢氧化钙,其碱性能够中和胃中的酸。
在此过程中,氢氧化钙与胃液中的碳酸氢钠发生反应,产生水、碳酸钠和二氧化碳,起到缓解胃酸过量的作用。
个人观点与理解氢氧化钙和碳酸氢钠的反应离子方程式是化学中常见的反应类型之一,它们在许多领域都有实际应用。
lecturehydrothermalreaction
制备放射性废料处理、特殊材料的固化成型、特种 复合材料等
按反应温度
1. 亚临界合成反应
• 多数沸石分子筛晶体的水热合成 • 反应温度范围在100~240C之间,适合于工业或实验室操
作
2. 超临界合成反应:利用作为反应介质的水在超临界 状态下的性质和反应物质在高温高压水热条件下的 特殊性质进行合成反应。
• 按加热条件:内热高压釜、外热高压釜
• 按实验体系:高压釜(封闭体系)、流动反应器和扩散反应器(开 放体系,在高温高压下,使溶液缓慢地连续通过反应器,并随时提 取反应液)
反应釜
• 等静压外热内压容器 • 等静压冷封自紧封高压容器 • 等静压锥封内压容器 • 等静压外热外压容器 • 等静压外热外压摇动反应器 • 等静压内加热高压容器 • 内热外压容器:约德反应器等
The hydrothermal method involves the heating of solid and liquid reagents with a suitable solvent (usually water) in a sealed vessel at temperatures of up to 250C.
Hydrothermal reactor
高压容器分类
• 按照密封方式:自紧式、外紧式
• 按密封的机械结构:法兰盘式、内螺塞式、大螺帽式、杠杆压机式
• 按压强产生方式:内压釜—靠釜内介质加温形成压强,根据介质填
充计算压强;
外压釜—压强靠外部加入并
控制
• 按设计者:Morey釜、Smith釜、Tuttle釜(冷封试管高压釜)、 Barnes摇动反应器
柠檬酸钠调控水热合成羟基磷灰石微球
柠檬酸钠调控水热合成羟基磷灰石微球马艺娟;郝丽静;杜绍龙;赵娜如【摘要】本研究采用四水硝酸钙(Ca(NO3)2·4H2O)和磷酸氢二铵((NH4)2HPO4)分别作为钙源和磷源,以丙酰胺为pH调节剂调控溶液的过饱和度,以柠檬酸钠为钙源缓释剂调控羟基磷灰石(Hydroxyapatite,HA)的形貌,经水热法处理成功制备出高结晶度、形貌均一和分散性良好的HA微球.采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)和扫描电镜(SEM)对反应产物进行了表征,研究了初始pH值、柠檬酸钠加入量和水热反应温度对HA结晶度、组成及形貌的影响.研究结果表明,当初始pH值为3,柠檬酸钠与钙源的摩尔比为1∶1.5,反应温度为180℃时,有利于HA微球的形成.【期刊名称】《无机材料学报》【年(卷),期】2014(029)003【总页数】5页(P284-288)【关键词】水热法;羟基磷灰石;微球;柠檬酸钠【作者】马艺娟;郝丽静;杜绍龙;赵娜如【作者单位】华南理工大学国家人体组织功能重建工程技术研究中心,广州510641;华南理工大学材料科学与工程学院,广州510641;华南理工大学国家人体组织功能重建工程技术研究中心,广州510641;华南理工大学材料科学与工程学院,广州510641;华南理工大学材料科学与工程学院,广州510641;华南理工大学国家人体组织功能重建工程技术研究中心,广州510641;华南理工大学材料科学与工程学院,广州510641【正文语种】中文【中图分类】TB321羟基磷灰石(Hydroxyapatite, HA), 是脊椎动物骨和牙齿组织的主要无机成分, 是一种磷酸钙盐。
HA具有较高强度、良好的生物活性和生物相容性,能与骨骼很好地结合[1-3], 是一种较理想的医用无机生物材料。
HA微球材料具有其他针状、片状或不规则形状材料所没有的良好性能, 如流动性好、堆积密度大、质量轻、强度高、不易团聚、注射性能良好和填充到复合材料中不易引起应力集中等, 适合作为抗生素等药物的缓释载体[6-8]、骨修复材料[9]、色谱分离[10]等。
锶含量对Ti-15Mo合金微弧氧化膜层及其磷灰石诱导能力的影响
第51卷 第1期 表面技术2022年1月 SURFACE TECHNOLOGY ·287·收稿日期:2021-03-20;修订日期:2021-05-26 Received :2021-03-20;Revised :2021-05-26基金项目:山东省自然科学基金面上项目(ZR2020ME006);山东省重点研发计划项目(2018GGX102027)Fund :General Program of Natural Science Foundation of Shandong Province (ZR2020ME006); Key Research and Development Program of Shandong Province (2018GGX102027) 作者简介:刘元才(1998—),男,硕士研究生,主要研究方向为金属材料加工及表面改性。
Biography :LIU Yuan-cai (1998—), Male, Master's degree, Research focus: metal material processing and surface modification. 通讯作者:徐铁伟(1982—),男,博士,副教授, 主要研究方向为航空结构材料的相变理论及强韧化。
Corresponding author :XU Tie-wei (1982—), Male, Doctor, Associate professor, Research focus: phase transformation theory and strengthening of aviatic materials.引文格式:刘元才, 徐铁伟, 张珊珊, 等. 锶含量对Ti-15Mo 合金微弧氧化膜层及其磷灰石诱导能力的影响[J]. 表面技术, 2022, 51(1): 287-295.LIU Yuan-cai, XU Tie-wei, ZHANG Shan-shan, et al. Effect of Strontium Content on Micro Arc Oxidation Coating and the Apatite Inducing 锶含量对Ti-15Mo 合金微弧氧化膜层及其磷灰石诱导能力的影响刘元才,徐铁伟,张珊珊,毕可晓,伏淑霞,曹磊,梁森(青岛理工大学 机械与汽车工程学院,山东 青岛 266525)摘 要:目的 提高Ti-15Mo 合金的生物相容性。
化学沉淀-水热法合成高矫顽力碳纳米管磁性复合材料(英文)
硅酸盐学报· 1772 ·2009年化学沉淀–水热法合成高矫顽力碳纳米管磁性复合材料曹慧群1,魏波1,王银治1,李耀刚2,朱美芳2(1. 深圳大学化学与化工学院,广东深圳 518060;2. 东华大学材料科学与工程学院,纤维改性国家重点试验室,上海 200051)摘要:采用化学沉淀–水热法成功的合成了一种新颖的Ni0.75Zn0.25Fe2O4 纳米晶包覆多壁碳纳米管(Ni0.75Zn0.25Fe2O4–CNTs)磁性复合材料。
采用透射电镜、X射线衍射、红外光谱和振动样品磁强计等方法对制备的样品进行了表征。
透射电镜结果表明Ni0.75Zn0.25Fe2O4纳米晶包覆在碳纳米管表面,纳米晶的大小为8~15nm。
X射线衍射结果表明:200℃是制备纳米Ni0.75Zn0.25Fe2O4包覆碳纳米管复合材料较好的反应条件,比合成单相Ni0.75Zn0.25Fe2O4纳米晶的温度要低。
磁性复合材料中Ni0.75Zn0.25Fe2O4晶体的大小约为16.0nm。
红外结果表明NiZn 的特征峰在590cm–1和414cm–1处。
磁滞回线结果表明室温下复合材料具有较高的矫顽力(H c=27244.3kA/m)。
关键词:碳纳米管;包覆;化学处理;磁性能中图分类号:TB33 文献标志码:A 文章编号:0454–5648(2009)10–1772–05SYNTHESIS OF A CARBON NANOTUBES MAGNETIC COMPOSITE BY CHEMICALPRECIPITATION–HYDROTHERMAL PROCESSCAO Huiqun1,WEI Bo1,WANG Yinzhi1,LI Yaogang2,ZHU Meifang2(1. College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060, Guangdong; 2. College of MaterialScience and Engineering, State Key Laboratory for Modification of Chemical Fibers and Polymer Material,Donghua University, Shanghai 200051, China)Abstract: A highly coercive magnetic composite (Ni0.75Zn0.25Fe2O4–CNTs) of multi-walled carbon nanotube (CNTs) coated with Ni0.75Zn0.25Fe2O4 nanocrystals was synthesized by chemical precipitation-hydrothermal process. The composite was characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform spectroscopy (FTIR) and vibrating sample magnetometer (VSM). The TEM images show that the CNTs surface is attached to Ni0.75Zn0.25Fe2O4 nanocrystals, and the average size of Ni0.75Zn0.25Fe2O4 nanocrystals is 8–15nm. The XRD results indicate that Ni0.75Zn0.25Fe2O4–CNTs can be obtained at 200℃as an appropriate hydrothermal temperature, which is lower than a synthesis temperature for single phase Ni0.75Zn0.25Fe2O4 nanocrystals. The particle size of Ni0.75Zn0.25Fe2O4 attached on the surface of CNTs is about 16nm. The FTIR results reflect that the bands at 590 and 414cm–1 are the characteristic bands of NiZn ferrite. The magnetic measurement by the VSM show that the compos-ite has a high coercive force of 27.24436RA/m at room temperature.Key words: carbon nanotubes; coating; chemical treatment; magnetic propertiesNiZn-ferrites have been used in information storage systems, medical diagnostics and shielding against elec-tromagnetic radiation due to the magnetic properties, chemical stability and corrosion resistance as well.[1–2] Also, the CNTs have received a considerable attention for their unique electrical and mechanical properties due to the promising applications.[3–4] Nano-structured magnetic materials have unique properties, compared to the bulk materials.[5] The combination of magnetic nano-structured materials and the CNTs as a developed material can result in higher electronic or magnetic properties. Some studies on the CNTs magnetic composites have been reported.[6–22] These investigations have been mainly focused on the syn- thesis of the CNTs magnetic composites[6–16] as well as the magnetic properties of the composites.[17–22] Liu et al.[23] prepared the CNTs–NiFe2O4 composites by hydrothermal process. The electrical conductivity of the prepared composite was increased by 5 times, compared to that of the NiFe2O4. It is known that since zinc can be used to improve the saturation magnetization; the addition of收稿日期:2009–07–11。
宁波2024年05版小学六年级下册T卷英语上册试卷(含答案)
宁波2024年05版小学六年级下册英语上册试卷(含答案)考试时间:80分钟(总分:120)A卷考试人:_________题号一二三四五总分得分一、综合题(共计100题)1、填空题:I can ______ (定期) reflect on my progress.2、填空题:The turtle swims slowly in the _______ (水).3、填空题:A __________ (催化循环) enhances reaction efficiency in chemical processing.4、What do you call a person who plays a musical instrument?A. MusicianB. SingerC. ComposerD. Conductor答案:A5、听力题:The chemical formula for calcium hydroxide is _______.6、How do you say "hand" in Spanish?A. ManoB. MainC. HandD. Maño7、听力题:The main gas in the air we breathe is _____.8、填空题:The ________ was a significant period in the evolution of human rights.The ________ (jacket) keeps me warm.10、填空题:Certain plants can ______ (抵抗) pests naturally.11、听力题:A _______ can be a beautiful centerpiece for a table.12、听力题:We eat ______ (snacks) during recess.13、听力题:A liquid that can dissolve a solute is called a _______.14、What is 3 + 5?A. 6B. 7C. 8D. 9答案:C15、填空题:Julius Caesar was a famous Roman _______. (统治者)16、听力题:A solution that contains the maximum amount of solute is _____ (saturated).17、What is the name of the famous ancient city in Iraq?A. BabylonB. NinevehC. UrD. All of the above18、听力题:The Magna Carta was signed in _______.19、What do we call the process of a caterpillar becoming a butterfly?A. MetamorphosisB. TransformationC. EvolutionD. Development答案:A20、填空题:I can ______ (表达) my thoughts clearly.The chemical symbol for rubidium is __________.22、听力题:The study of chemicals and their reactions is known as _______.23、What is the name of the famous explorer who sailed across the ocean in 1492?A. Vasco da GamaB. Ferdinand MagellanC. Christopher ColumbusD. Marco Polo答案:C24、What is the name of the famous ancient city in Jordan?A. PetraB. BabylonC. AthensD. Rome答案:A25、填空题:I want to grow _____ (蔬菜) this year.26、填空题:We can play with a ________ outside.27、选择题:What do you call the part of the plant that absorbs water?A. LeafB. StemC. RootD. Flower28、听力题:We enjoy going to the ___. (beach) every summer.29、听力题:A mixture that contains two or more phases is called a ______.30、What is the capital of Canada?A. TorontoB. OttawaC. VancouverD. MontrealI like to _______ (与朋友一起)去健身房。
含石灰水热条件下硅藻土微结构演化及其对亚甲基蓝吸附性能的影响
型场发射扫描电子显微镜(SEM)和日本电子株式会
所的 JEM 1200EX 型透射电子显微镜(TEM)观察样
品的微观结构。用北京精微高博技术有限公司的
JW-BK 型静态氮吸附仪测定样品的比表面积、孔径
及孔体积。用英国 Malvern 公司的 ZEN 3600 型 Zeta
电位测试仪测试样品在不同 pH 值下的 Zeta 电位,
· 568 ·
《硅酸盐学报》 J Chin Ceram Soc, 2020, 48(4): 567–576
2020 年
染料废水直接排放,会对环境和人体造成很大 危害[1‒2]。目前,染料废水的处理方法主要有物理吸 附法、光催化氧化法、絮凝沉淀法、电化学法、生 物法[3‒4]等,其中物理吸附法以处理容量大、操作简 便、脱除效率高等优点,受到广泛重视[5]。
Abstract: Si‒Ca porous mineral material was prepared with calcine diatomite and slaked lime via a hydrothermal reaction method. The microstructure of diatomite under lime-containing hydrothermal conditions was characterized. The effect of microstructure change of diatomite on its adsorption performance was investigated with methylene blue as an adsorbent, and the mechanism of Si‒Ca porous mineral material was analyzed. The results show that SiO2 in calcined diatomite reacts with Ca(OH)2 to generate clinotobermorite under the lime-containing hydrothermal conditions. The diatoms disk structure disappears and the flaky clinotobermorite stacks up into Si‒Ca porous mineral. The volume of porous material is 10 times greater than that of calcined diatomite, and the amount of hydroxyl on the surface of the material increases. Si‒Ca porous mineral material exhibits good methylene blue adsorption and recycling performance. The adsorption capacity of Si‒Ca porous mineral is 6.5 times greater than that of calcined diatomite, and its saturated adsorption capacity can reach 384.51 mg/g. The adsorption process of diatomite board towards methylene blue can be described by the pseudo-second-order kinetic model. Its adsorption isotherms can be fitted by the Langmuir model, and the adsorption is a spontaneous endothermic process. When pH value>4, the surface of Si‒Ca porous mineral is negatively charged, the adsorption is completed by the active hydroxyl group of the mineral surface and the quaternary ammonium salt cationic in the solution form the hydrogen bond through electrostatic attraction, Also, the large specific surface area of Si‒Ca porous mineral can provide the more adsorption sites for methylene blue, which is conducive to the adsorption.
- 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)。
Chemical Laboratory of the Geological Survey,Xtockholm 50, Sweden
Received Sepl ember 16, 1967
The hydrothermal reactions between calcium hydroxide and silica over the temperature range 120-160" were investigatetl
. andothe possibility of occurring equilibria discussed in connection with the results earlier published for the reactions a t 180-
220 At about 120-140' two-stage reactions take place. During the first stage the phase B is formed, thifi phase not being a chemical compound in real sense but a mixture of crystallites of nearly sub-X-ray dimensions as described earlier. The second stage yields hases, the characters of which are dependent on the molar proportion calcium hydroxide: @ea of the reaction mixtures; t l e proportion 0 to about 0.67: 1 yields the Z-phase of unknown composition mentioned, In the earlier paper, in mixtures of the molar proportions 0.67 to about 1.25: 1 the tobermorite phase is formed; in the mixtures 1.25 to
The mineralogical and practical interest concomitant with these results obviously promotes new investigations, designed t o discover some new conditions for the formation of the Z-phase and t o follow the reaction stages a t somewhat lower temperature.
Feb., 1958
THEREACTIONBETWEEN CALCIUMHYDROXIDANED AMORPHOUSSILICA
223
HYDROTHERMAL REACTIONS BETWEEN CALCIUM HYDROXIDE AND
AMORPHOUS SILICA; THE REACTIONS BETWEEN 120 AND 160'
z- 2: 1 and with a further excess of lime the a-dicalcium sllicate monohydrate crystallizes. At higher temperatures (>160')
begins the range of the thJee-stage reactions earlier described, The possible temperature range of equilibrium of the phase seems to be 130-150 ; the X-ray diffraction of this phase is given. The tobermorite phase has its upper teinperature boundary for a real equilibrium a t about 150" and above this temperature it recrystallizes into the xonotlite compound. The a-dicalcium silicate seems to have an uppw temperature boundary close to 160' and a t higher temperatures ,the hillebrandite phase is the stable compound. In the light of the results the formation of the corresponding minerals In nature is discussed and the reason for the discrepancies between properties of the synthetic compounds and the minerals was Buggested. The exothermal reaction type of the transformations is emphasized.
One object of the present investigation was to find the experimental conditions under which the phase Z is formed in its least adulterated state. The molar ratio CaO:SiOz in the reaction mixtures was therefore changed in steps of about 0.1 mole CaO per mole Si02throughout the range 0.25: 1 to 1:1 . The behavior of only some of these mixtures can be mentioned in this report. The period of autoclave treatment was, in most cases, 7 days, although where lower temperature (120") was used, the period was sometimes extended.
Materials and Experimental Details.-The materials, silica and lime, were identical with those used in the earlier experiments and described in the i,eports. The special autoclave, with a manometer control of the pressure and valves for removing the air, was the same as that earlier described and its use was necessary to reach experimental conditions which could be precisely defined.
Results
It is well-kno G. 0. Assrtrsson, THISJOURNAL, 61,473 (1957).
autoclave treatment of lime-silica mixtures that real equilibria are sometimes difficult to reach especially a t lower temperatures. It seems, however, to be possible to get a good survey of the reactions within the temperature range 120-1GO" without reaching definitive equilibria by a combination of the results according t,othe phase rule.
Downloaded by WUHAN UNIV OF TECH on July 30, 2009 Published on May 1, 2002 on | doi: 10.1021/j150560a019
I n an earlier paper1 were given the results of the investigation concerning the equilibria of calcium silicate hydrates, formed during autoclave treatment of mixtures of amorphous silica and calcium hydroxide at temperatures between 180 and 220". Three reaction stages were shown to take place during the crystallization of the silicate hydrates, and the formation was established of a new phase designated Z.
In spite of all the precautions concerning the experimental conditions it was sometimes concluded that details of the experiments must have varied, as some of the autoclave products could be slightly better crystallized than others even if the phases were the same. The temperature of the furnace for heating the autoclave and of the autoclave itself were controlled automatically, and the heating up period was always identical. There seems therefore to lie n certain disposition for a crystallization of the reaction products caused by nuclear crystallization centers. These observations are especially pertinent to the recrystallization of the phase B, but the variations are without substantial importance in the establishment of the phase formation. Some experiments, however, were repeated as a control on the formation of the phases and, according to t,he phme rule, the same phases were always recovered.