Solvent extraction
油脂加工术语
3浸出solvent extraction3.1溶剂solvent 能够以任何比例，充分和迅速的溶解油脂的有机物质。
（6号溶剂油、丙酮等）3.2 溶剂浸出solvent extraction 亦称"萃取"。
用有机溶剂提取油料中油脂的过程。
3.2.1溶剂比solvent ratio 单位时间内被浸出物料与溶剂的重量比。
3.2.2浓度差concentration gradient 亦称"浓度梯度"。
在浸出过程中，料胚内外的混合油浓度之差。
3.2.3喷淋式浸出percolation extraction 溶剂呈喷淋状态与料胚接触而完成浸出过程的方式。
3.2.4浸泡式浸出immersion extracion 料胚浸泡在溶剂中完成浸出过程的方式。
3.2.5混合式浸出combined extractioa 喷淋与浸泡相结合的浸出方式。
3.2.6直接浸出direct extraction 亦称"一次浸出"。
油料经预处理后直接进行浸出取油的工艺。
3.2.7预榨浸出pre-pressing extraction 油料经预榨取出部分油脂后，再将含油较高的饼进行浸出的工艺。
3.2.8间歇式浸出batch extraction 料胚进人浸出器、粕自浸出器中卸出, 新鲜溶剂的注入和浓混合油的抽出等工艺操作是分批、间断、周期进行的浸出过程。
3.2.9连续式浸出continuous extraction 料胚进入浸出器、粕自浸出器卸出，新鲜溶剂的注入和浓混合油的抽出等工艺操作是连续不断进行的浸出过程。
3.2.10 浸出温度extraction temperature 浸出过程中，根据溶剂馏程和浸出工艺拟定的温度条件。
3.2.11浸出时间extraction time 料胚入浸至出粕所需的时间。
3.2.12 渗透性permeability 浸出过程中，溶剂渗透到料胚内部孔隙中穿过料层的程度。
SOLVENT EXTRACTION PROCESS
专利名称：SOLVENT EXTRACTION PROCESS 发明人：G. VENTRON申请号：AU6039580申请日：19800714公开号：AU6039580A公开日：19810205专利内容由知识产权出版社提供摘要：The invention relates to a liquid liquid process for extracting metals from aqueous solution. The process comprises bridging into contact the aqueous solution with an organic phase containing at least one complex-forming agent insoluble in water and corresponding to the general formula: in which Z<1> and Z<2> represent an oxygen atom or a sulphur atom and may be the same or different and R<1> and R<2> which may be the same or different represent straight or branched alkyl, cycloalkyl, aryl or aralkyl groups containing at least one electron-attracting group, to extract the metal from the aqueous solution The process is used to extract nickel, copper, uranium, molybdenum, lead cadmium, cobalt, iron, zinc, vanadium, tin and tungsten A second stage may be employed wherein the organic solution containing the metal is contacted with a second aqueous solution to strip the metal from the organic to the second aqueous solution 申请人：BITISH PETROLEUM CO. LTD., THE更多信息请下载全文后查看。
Solvent Extraction
Solvent ExtractionIntroductionThe separation of the components of a mixture by treatment with a solvent in which one or more the desired components is preferentially is known as solvent extraction ,also known as liquid-liquid extraction.In this operation ,it is essential that the liquid-mixture feed and solvent are at least partially if not completely immiscible and,in essence ,three stages are involved:(a)Bringing the feed mixture and solvent into intimate contact,(b)Separation of the resulting two phases,and(c)Removal and recovery of the solvent from each phase.Extraction is in many ways complementary to distillation and is preferable in the following case:(a)Where distillation would require excessive amount of heat ,such as,for example,when the relative volatility is near unity.(b)When the formation of azeotropes limits the degree of separation obtainable in distillation.(c)When heating must be avoided.(d)When the components to be separated are quite in nature .Important applications of liquid-liquid extraction include the separation of aromatics from kerosene-based fuel oils to improve their burning qualities and separation of aromatics from paraffin and naphthenic compounds to improve the temperature-viscosity characteristics of lubricating oils.It may also be used to obtain,for example,relatively pure compounds such benzene,toluene,and xylene form catalytically produced reformats in the oil industry ,in the production of anhydrous acetic acid ,in the extraction of phenol from coal tar liquors ,and in the metallurgical biotechnology industries.In all extraction processes,the important feature is the selective nature of the solvent,in that the separation of compounds is based on differences in solubilities,rather than differences in volatilitiesas all in distillation .In recent years,it has become possible to use computerised Techniques to aid in the choice of a solvent with required selectivity and to design appropriate molecular structures.Extraction ProcessThe three steps outlined in Introduction,necessary in all liquid-liquid extraction operations,may be carried out either as a batch or as a continuous process.In the single-stage batch process illustrated in Figure 8-2-1,the solvent and solution are mixed together and then allowed to separate into the two phases -the extract E containing the required solute in the added solvent and raffinate R ,the solution with some associated solvent.With this simple arrangement mixing and separation occur in the same vessel.A continuous two-stage operation is shown in Figure 8-2-2,where the mixers and separators are shown as separate vessel.There are three main forms of equipment.First there is the mixer -setter as shown in Figure 8-2-1,secondly ,there in the column type of design with trays or packing as in distillation and,thirdly ,there are a varietyof units incorporating rotating devices such as the Scheibel and the Podbielniak extractions.In all cases,the extraction units are followed by distillation or a similar operation in order to recover the solvent and the solute.One system for separating benzene,toluene,and xylene groups form light feed-stocks is shown in 8-2-3,where n-methylpyrolidone(NMP) with the addition of some glycol is used as the solvent The feed is passed to a multistage extractor arranged as a tower from which an aromatics -free raffinate is obtained at the top.The extract stream containing the solvent ,aromatics,and low boiling non-aromatics is distilled to provide the extractor recycle stream as a top product,and a mixture of aromatics and solvent at the bottom.This stream passes to a stripper from which the glycol and the aromatics are recovered.This is a computer system illustrating the need for careful recycling and recovery of solvent.The mechanism of transfer solute from one phase to the second is one of molecular and eddy diffusion and the concepts of phase equilibrium,interfacial area,and surface renewal are all similar in principle to those met in distillation and absorption ,even though ,in liquid-liquid extraction,dispersion is effected by mechanical means including pumping and agitation,except in standard packed columns.In formulating design criteria for extraction equipment,it is necessary to take Into account the equilibrium condition for the distribution of solute between the phases as this determines the maximum degree of separation possible in a single stage.The resistance to diffusion and,in the case of chemical effects,the kinetics are also important in that these determine the residence time required to bring about near equilibrium in stage-wise unit,or the height of a transfer unit in a differential contactor.The transfer rate is given by the accepted equation:Rate per unit interfacial area =kΔCWhere k is a area mass transfer coefficient and ΔC is a c oncentration driving force.A high value of k can be obtained only if turbulent of eddy conditions prevail and ,although these many be readily achieved in the continuous phase by some form of agitation,it is very difficult to generate eddies in the drops which constitute the dispersed phase.Selected from Coulson and Richrdon’s chemical engineering Volume 2,5th Edition ,by John FrancisRicharddson,Butterworth-Heinemann,2002.New Words and Expressionssolvent extraction 溶剂萃取liquid-liquid extraction 液-液萃取Immiscible 不能混溶的Paraffin 煤油，石蜡lubricating oil 润滑油coal tar 煤焦油batch process 间歇过程continuous process 连续过程Raffinate 萃取液，残油液Vessel 器皿，容器，釜Mixer 搅拌器Separator 分离器Scheibel extractor 赛贝尔萃取器Podbielniak extractor 波特贝尔尼克萃取器Stripper 汽提塔Molecular diffusion 分子扩散Eddy diffusion 涡流扩散Mass transfer coefficient 传质系数Concentration driving force 浓度推动力Word to KnowExtract phase 萃取相Raffinate phase 萃余相Reextraction,reverse extraction 反萃取Liquid-solid extraction, LSE液-固萃取Solid phase extraction 固相萃取Membrane extraction 膜萃取Liquid membrane extraction 液膜萃取法Distribution ratio 分配比Partition coefficient 分配系数Extract 萃取液Extractant 萃取剂Separation factor 分离系数Decontamination factor 纯化(净化)系数Extraction factor 萃取因数The Nernst distribution law 能斯特分布定律Reactive extraction 反应萃取Nondispersive solvent extraction 非扩散溶剂萃取Two-aqueous phase extraction, ATPS双水相萃取技术Reverse micellar extraction 反胶团萃取Supercritical fluid extraction 超临界萃取Ion pair extraction 离子对萃取Pressurized solvent extraction 压力溶剂萃取Accelerate solvent extraction 加速溶剂萃取Microemulsion 微乳Colloidal liquid aphron 胶质液体泡沫Baffle-plate column mixer 挡板混合塔spray column 喷雾塔Packed column 填充塔Centrfugal extraction 离心萃取器Mixer-settler extraction 混合-澄清式萃取器Fractional extraction 分馏萃取Notes1.The separation of the components of a liquid mixture by treatment with a solvent in which one or more of the desired components is preferentially soluble is known as solventextraction,also known as liquid-liquid extraction.参考译文：液体混合物组分经过溶剂的处理，一种或多种组分优先在溶剂中溶剂中溶解，从而得以分离的过程称为溶剂萃取，也称为液-液萃取。
大豆油萃取工艺流程
大豆油萃取工艺流程英文回答：Soybean Oil Extraction Process.Soybean oil extraction involves several key steps to separate the oil from the soybean seeds:1. Cleaning and Conditioning: The soybeans are cleaned to remove foreign materials, such as dirt and debris. They are then conditioned by adjusting their moisture content and temperature to optimize oil extraction.2. Flaking: The soybeans are passed through a roller mill to break them into thin flakes. This increases the surface area of the soybeans, facilitating oil extraction.3. Solvent Extraction: The flaked soybeans are extracted with a solvent, typically hexane, in a continuous extractor. The solvent dissolves the oil, forming an oil-solvent mixture called miscella.4. Desolventizing: The miscella is heated to evaporate the solvent, leaving behind the crude soybean oil. The solvent is recovered and reused in the extraction process.5. Oil Refining: The crude soybean oil undergoes refining processes to remove impurities, such as gums, phospholipids, and free fatty acids. This involves degumming, neutralization, bleaching, and deodorization.6. Deodorization: The final step is deodorization, which removes volatile compounds responsible for undesirable odors. This is achieved through steam distillation and/or chemical treatment.中文回答：大豆油萃取工艺流程。
第11章液液萃取
11液液萃取（溶剂萃取）Liquid-liquid extraction(Solventextraction)11.1 概述一、液液萃取过程：1、液液萃取原理：根据液体混合物中各组分在某溶剂中溶解度的差异，而对液体混合物实施分离的方法，也是重要的单元操作之一。
溶质 A + 萃取剂 S——————〉S+A (B) 萃取相 Extract分层稀释剂 B B + A (S…少量) 萃余相 Raffinate（残液）一般伴随搅拌过程 => 形成两相系统，并造成溶质在两相间的不平衡则萃取的本质：液液两相间的传质过程，即萃取过程是溶质在两个液相之间重新分配的过程，即通过相际传质来达到分离和提纯。
溶剂 extractant（solvent)S 的基本条件：a、S 不能与被分离混合物完全互溶，只能部分互溶；b、溶剂具有选择性，即溶剂对A、B两组分具有不同溶解能力。
即（萃取相内）（萃余相内）最理想情况： B 与 S 完全不互溶 => 如同吸收过程： B 为惰性组分相同：数学描述和计算实际情况：三组分分别出现于两液相内，情况变复杂2 、工业萃取过程：萃取不能完全分离液体混合物，往往须精馏或反萃取对萃取相和萃余相进行分离，而溶剂可循环使用。
实质：将一个难于分离的混合物转变为两个易于分离的混合物举例：稀醋酸水溶液的分离：萃取剂：醋酸乙酯3 、萃取过程的经济性：取决于后继的两个分离过程是否较原液体混合物的直接分离更容易实现（ 1 ）萃取过程的优势：（与精馏的关系）ａ、可分离相对挥发度小或形成恒沸物的液体混合物；ｂ、无相变：液体混合物的浓度很低时，精馏过于耗能（须将大量 B 汽化）；ｃ、常温操作：当液体混合物中含有热敏性物质时，萃取可避免受热；ｄ、两相流体：与吸附离子交换相比，操作方便。
（ 2 ）萃取剂的选择——萃取过程的经济性a、分子中至少有一个功能基，可以与被萃取物质结合成萃合物；b、分子中必须有相当长的烃链或芳香环，可使萃取剂和萃合物容易溶解于有机相，一般认为萃取剂的分子量在350－500之间较为合适。
生物分离工程 第五章 萃取
多级逆流萃取
L1, y0 1 H, x1
y1 2 x2
y2
yn-2 n-1
yn-1 n xn
yn, L
x3
xn-1
xn+1, H
确定要达到一定的回收率所需萃取的级数
E=kL/H （E萃取因子，k分配系数） 1- φn= (En+1-E)/ (En+1-1) 1- φn=n/(n+1) (φ萃余分数）(E=1时，据罗比塔极限法得之）
and Solid phase extraction.利用在两个互不相溶的液相中各种组分
（包括目的产物）溶解度的不同，从而达到分离的目的 （萃取剂、萃 取液、萃余液）
The extraction classifications萃取的分类：
By physical conditions of extract solvents and materials: L-L extraction, L-S extraction and SFE根据萃取剂和原料的物理状态分：液液萃取（有机溶剂萃取、 双水相萃取、液膜萃取和反胶束萃取等），液固萃取，超临界流体萃取等
表面活性剂：稳定油水分界面的重要组成，相当于生物膜类脂双
分子层的亲水端，含量在1%-5%
流动载体：相当于生物膜的蛋白质载体 膜增强剂：
液膜分类（p87-88） 乳状液膜：（W/O)/W型和(O/W)/O型，在生物分离中主要是（W/O)/W
型
支撑液膜： 流动液膜： 液膜萃取机理 单纯迁移：又称物理渗透
By extraction flowsheet: single stage extraction and multistage extraction.根
extraction常用含义
extraction常用含义
extraction 的常用含义有：
1. 提取：从混合物或原材料中分离出特定的成分或物质。
2. 提取物：从混合物或原材料中分离出来的特定成分或物质。
3. 抽取：从一个文本、数据库或其他数据源中获取特定的信息或数据。
4. 卸酸：在化学反应过程中，用一种不相溶的有机溶剂将酸性物质从水溶液中抽取出来。
5. 抽出：通过施加外力或采用机械方式将物质从其原处移动或分离出来。
如牙齿的拔出、土壤的抽出等。
6. 提炼：从混合物、原料或废料中分离出有用的物质或能量，常用于对矿石、石油等的加工过程中。
7. 抽取术语：指在音频领域中的一种信号处理技术，通过使用滤波器将特定频率范围的信号分离出来。
请根据具体语境来确定 extraction 的意思。
1-萃取剂及相关溶剂
RO—的电负性大于R—， 故RO—的吸引电子能力大于R—， R—一般被看作是给电子基团
部分原子及基团的电负性 F O Cl CCl3— RO— CH2Cl— C6H5— CH3— R— H 4.0 3.5 3.0 2.95 2.9 2.6 2.34 2.07 2.0 2.25
◆ 取代酰胺以羰基为官能团，能够从酸性溶液中萃取金属络阴离子。
第二章 萃取剂及相关溶剂
（二）酸性萃取剂
这类萃取剂在水中可在水中电离出H+离子，故称为酸性萃取剂。 在萃取过程中一般是H+和水中的阳离子进行交换，故也叫做液
体阳离子交换剂或阳离子萃取剂。
① 弱酸性萃取剂：电离常数Ka~10-5，如羧酸 按酸性分类： ② 中强酸性萃取剂：电离常数Ka~10-2，如二烷基磷酸
④螯合萃取剂：这是一类在分子中同时含有两个或两个 以上配位原子，可与中央离子形成螯合 环的有机物。
第二章 萃取剂及相关溶剂
对萃取剂的一般要求： （1）有较大的萃取容量 （2）选择性好 （3）易于反萃，不易发生乳化 （4）比重小，粘度低，表面张力大，沸点高，挥发性小， 闪点高，在水中溶解度小 （5）化学稳定性好，毒性小 （6）容易制备，来源丰富，价格便宜
O R
TBP(磷酸三丁酯) (C4H9O)3P=O
② 烃基膦酸二酯
O R—OH H O—P—O H —R
O H HO—R
③ 二烃基膦酸单酯
O R—OH H O—P—O H —R
O H R
第二章 萃取剂及相关溶剂
O
P350(甲基膦酸二甲庚酯)
RO—P— R
O
O R
溶剂萃取基本原理Phil
Strip OC – to minimise organic entrainment to EW. 反萃 有机相连续－将有机夹带入电积降到最低。
Australia
Aqueous continuous emulsion – AC 水相连续乳状液
Organic droplets surrounded by aqueous phase 有机小液滴被水相包围
Aqueous Continuous emulsion 水相连续乳状液
Desired Mixer Emulsion conditions 期望的混合室乳状液条件
铜溶剂萃取 – 化学
• 羟基肟萃取剂被用于从料液中选择性的萃取铜进入有机相;
2RH + CuSO4 → R2Cu + H2SO4
反萃有机相 + 料液
负债有机相 + 萃余液
回收有机去萃取 • 强酸被用于从有机相中反萃铜进入水相 (如, 适合于电积的电积
贫液);
R2Cu + H2SO4 → 2RH + CuSO4
• Chloride - can be transferred to EW, affecting EW and the environment. 氯－能够被传递到电积，影响电积和环境
• Manganese – can be transferred to EW and can degrade the organic phase in SX. 锰－能够被传递到电积，能够在溶剂萃取中降解有机相
Specific gravity of organic phase ~ 0.8 有机相比重～0.8
第三章 溶剂萃取分离法-xin
V水 V有 D
5
V水 V有
)
n
4 . 07 10
0 . 018 (
V水 /V有 40 ＋ V 水 / V 有
〕
2
V水/V有=2
第二节 溶剂萃取分离法
例6. 某物质的水溶液100 mL，用5份10 mL萃取剂溶液
连续萃取5次，总萃取率为87 % ，则该物质在此萃取体系
中的分配比是多少?
解：
解：
0 . 84 D
D VW VO
D = 5.25
第二节 溶剂萃取分离法
0 . 97 1 (
VW DV O V W
)
n
0 . 03 (
1 D 1
)
n
(
1 6 . 25
)
n
1.523=0.795n 即n=2(次)
n=1.9
第二节 溶剂萃取分离法
例4.弱酸HA在CH3Cl和水中的分配比为8.20，取
一、溶剂萃取的发展史
1842年，Peligot首先用二乙醚萃取硝酸铀酰。 1863年，Brawn将二乙醚用于硫氰酸盐的萃取。 1892年，Rothe等用乙醚从浓盐酸中萃取HFeCl4 1872年，Berthelot提出了萃取平衡的关系式。
1891年，Nernst提出Nernst分配定律。
20世纪40年代，自采用TBP（磷酸三丁酯）作为核燃 料的萃取剂以来，萃取技术得到了更广泛的发展。
E mo mn mo
0 . 87 1 (
mo mo
mn mo
)
5
设 m o 1g ,
0 . 87 1 (
则： E 1 m n
100
有机溶剂萃取
双水相萃取
Two-aqueous phase extraction
基因工程产品如蛋白质和酶往往是胞内 产品，需经细胞破碎后才能提取、纯化， 细胞颗粒尺寸的变化给固-液分离带来了困 难，同时这类产品的活性和功能对pH值、 温度和离子强度等环境因素特别敏感。
由于它们在有机溶剂中的溶解度低并且会变 性，因此传统的溶剂萃取法并不适合。
1.成相聚合物
– 分子量：降低聚合物的分子量，则蛋 白质容易分配于富含该聚合物的相中 。 – 总浓度：越大则两相性质的差别越大 ，系线越长，蛋白质越容易分配于其 中的某一相。
2.盐和缓冲液的影响
盐的种类和浓度对分配系数的影响主要反映在
对相间电位和蛋白质疏水性的影响。在双聚合 物系统中，无机离子具有各自的分配系数，不 同电解质的正负离子的分配系数个同，当双水 相系统中含有这些电解质时，由于两相均应各 自保持电中性，从而产生不同的相间电位，因 此，盐的种类(离子组成)影响蛋白质、核酸等 生物大分子的分配系数，盐浓度不仅影响蛋白 质的表面疏水性，而且扰乱双水相系统，改变 各相中成相物质的组成和相体积比。
溶剂的回收和再容易 化学稳定性好,不易分解,对设备腐蚀性小
经济性好,价廉易得
安全性好,无毒性或毒性低.
不同的萃取剂对溶质的萃取效果不同。
如疏水性的青霉素G和V酸性很强，其 pKa值为2.5～3.1，相对分子质量分别为 334和350，适宜用有机溶剂从发酵液中 萃取，在pH 2.5～3.0范围内，用乙酸戊 酯和乙酸丁酯作为萃取剂的萃取效率高 （如下表）。
如提Vb12时加硫铵，促进Vb12从水 转入有机相中；提青霉素进加NaCl. 促进青霉素从水转入有机相中
产物易溶于有机溶剂中.复合物在一定条 件下又要易分解.如青霉素可用脂肪碱作 带溶剂.（化学萃取）
萃取分离知识
1. 中性配合萃取体系
特点 • 被萃取物在水相中以中性分子形式存在 • 萃取剂也是中性分子（含有适当配位基团） • 被萃取物与萃取剂形成中性配合物 例 TBP－煤油体系从硝酸溶液中萃取硝酸铀酰
被萃取物形式：UO2(NO3) 2 （铀的其他形态如UO22＋, UO2NO3＋等不被萃取） 萃取剂：TBP（磷酸三丁酯） 中性配合物： UO2(NO3) 2· 2TBP
对于一次萃取： ② E=
可见：E的大小取决于分配比和相比（两相体积比）
③ 经过n次萃取后，水相中剩余A质量仅为mn,
则
mn =
m（ 0
V水 DV有 V水
n ）
m0为水相中A的最初浓度，即总浓度
4. 分离系数 表示A、B两组分在萃取中被分离的情况：
A / B D A / DB
当DA和DB比较接近时，分离系数β接近于1，表明A、B两组 分难以通过萃取分离。反之，DA和DB相差越大，二者被分离的 程度越好。
配合物的稳定性与冠（穴）醚的空穴直径，冠（穴）醚环上 杂原子种类、数目和空间排列，环上取代基，金属离子的体 积和电荷，溶剂性质等有关。 穴醚因具有两个以上环，为三维结构化合物，其球形空穴对
金属离子的配合能力比单环的冠醚要大得多。
冠（穴）醚的亲水杂原子向内侧，外侧是疏水-CH2-CH2-基， 因而使萃取配合物在有机相溶解性增加。
溶剂萃取的优缺点 优点：仪器设备简单，操作方便。
分离选择性高。
应用范围广（无机和有机物；常量和微量组分）。
处理量大，适于工业分离，易于连续自动操作。
缺点：有机溶剂易挥发，多对人体有害。
手工操作比较麻烦，费时。 分离效率不高（比LC小2－3个数量级）。
（二） 基本概念
第四章萃取分离法详解
萃余率：
原 萃始 余料 液液 中中 溶 1溶 质 0% 0质 总 E总 1量 1量 10% 0
理论收率：
111 10 % 0E 10 %0
E1
E1
例如：
洁霉素在20℃和pH10.0时表观分配系数〔丁 醇/水〕为18。用等量的丁醇萃取料液中的 洁霉素，计算可得理论收率
1 1810% 09.4 7%
第四章萃取分离法详解
根底知识
• 萃取又称溶剂萃取，亦称抽提〔通用于石 油炼制工业〕，是一种用液态的萃取剂处 理与之不互溶的双组分或多组分溶液，实 现组分别离的传质别离过程，是一种广泛 应用的单元操作。
• 将溴水和苯在分液漏斗里混合后振荡、静 置〔静置后液体分层，Br2被溶解到苯里 ，苯与水互不相溶，苯比水轻在上层，因 溶有Br2呈橙红色，水在下层为无色〕、 分液即完成萃取
1 81
假理设论改收用率1：1/3体 积丁6醇1 萃0 取% 0 ，E8 1.57% 811/3 6
61
注：当分配系数一样而萃取剂用量减少时， 其萃取率下降。
〔二〕多级错流萃取
萃余率：
nE11E2 11 En110 % 0
理论收率
n
1
E1n
10% 0
1 n 1E 11 n 1% 0 0 E E 1 1 n n1 1% 00
• ①多级错流萃取。料液和各级萃余液都与新颖的萃 取剂接触，可达较高萃取率。但萃取剂用量大，萃 取液平均浓度低。
• ②多级逆流萃取。料液与萃取剂分别从级联〔或板 式塔〕的两端参加，在级间作逆向流动，最后成为 萃余液和萃取液，各自从另一端离去。料液和萃取 剂各自经过屡次萃取，因此萃取率较高，萃取液中 被萃组分的浓度也较高，这是工业萃取常用的流程 。
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Unit Three第3单元Unit Operations and Transport Processes (II)单元操作和传递过程Lesson 9第9课Solvent Extraction溶剂萃取Separation of two or more components of a liquid solution溶液is one of the commonest of chemical-engineering problems.1、两种或两种以上组分溶液的分离是最常见的化学工程问题之一。
The most usual常用的procedures程序are evaporation蒸发, fractional crystallization部分结晶, and distillation精馏, in which separation is accomplished by taking advantage of利用the differing solubilities溶解性or volatilities挥发性of the components.2、最常用的程序是蒸发、分步结晶和精馏，其主要是利用不同组分之间溶解性和挥发性的差异来是实现的。
Alternatively或者, it is often possible to accomplish the desired 要求的separation by bringing the liquid in contact with a second liquid which selectively选择性地removes one or more of the components of the solution so treated'.3、或是，让溶液和第二种液体相接触，其可以选择性的移除被处理溶液中的一个或是更多的组分来实现所要求的分离经常也可以成为可能。
Separation is accomplished because certain of the components某种物质are more readily容易地、乐意地soluble than others in the solvent 溶剂employed.4、分离可以进行是因为某些组分相比其他组分更容易溶解于所选用的溶剂中。
The solution and the solvent must not be completely miscible完全互溶, since the purpose is to effect the desired separation by mechanical separation of the two liquid phases.5、溶液和溶剂必须不能完全互溶，因为目的是为了通过两种液相的机械分离来达到所要求的分离的。
The separation is accomplished without vaporization汽化, thought evaporation or distillation is usually required to recover the separated components from the two liquid product streams.6、这样的分离没有汽化现象，尽管蒸发和精馏经常被用来去从两个液态产品流中去得到被分离组分。
Solvent extraction also refers to引用the treatment of a solid with a solvent, as in像在the extraction of oil from cottonseed棉籽.7、溶剂萃取也指用溶剂来处理固体，比如从棉籽里面萃取油。
The present text, however, will be confined to solvent extraction processes in which a liquid solution is treated with a liquid solvent phase (called liquid-liquid extraction).8、然而，目前的文本均被定义为融溶剂萃取，即用液体溶剂来处理溶液（所谓的液液萃取）One of the common applications of extraction is in the separation of compounds differing不同的化合物as to关于chemical type化学类型but difficult to separate by distillation because their volatilities挥发性do not differ greatly3.9、对组分之间的挥发度相差不大而用精馏方法又难以分离的不同化学类型的化合物的分离，是萃取的常规应用之一。
An example is the separation of aromatic and paraffin hydrocarbons芳烃和烷烃in the solvent ref i ning lubricating oils.10、一个例子就是用精制润滑油溶剂分离芳烃和烷烃。
In other cases solvent extraction is employed because the components组分are heat-sensitive热敏性and tend to decompose分解at the Ordinary普通的temperatures of distillation or evaporation.11、溶剂萃取还被应用在热敏性的和在精馏和蒸发的普通温度下易发生分解的物质分离中。
Penicillin, streptomycin, and other biologicals produced in dilute稀的solutions may be concentrated浓缩and purif i ed提纯by solvent extraction in order that the pure products may be recovered by fractional crystallization分步结晶or precipitation沉淀5.12、从稀溶液中制取青霉素和链霉素或是其他生物制药，可以先通过溶剂萃取的方法来浓缩和提纯，以便在分步结晶和沉淀中获得纯净产品。
In some cases在某些情况下extraction may prove economical in instances实例where distillation is also entirely完全地practical.定语13、在某些情况下，精馏也完全可行的实例中萃取显得更经济。
Thus Othmer and Trueger claim heat savings for节省the solvent extraction of acetone丙酮and ethyl alcohol乙醇from dilute aqueous solution水的稀溶液, as compared with standard rectif i cation精馏practice for these separations.14、因此，Othmer和Trueger声称，从水的稀溶液中萃取丙酮和乙醇与对于这种分离的标准的精馏操作相比要比节省热量。
This claim is based on the fact that moderately适度地concentrated extracts may be obtained by the use of proper solvents and that the heatrequirement for distillation from these extracts may be less than for distillation of the original dilute aqueous solutions.15、这个宣称基于一个事实就是适度地浓缩萃取液可以通过合适的溶剂来得到，对精馏来说这些这些萃取液的热量需求要低于对于最初的水的稀溶液的精馏。
The solvent extraction process involves the four operations of:16、溶剂萃取过程包括四个操作：a) bringing solvent and solution into intimate contact;17、把溶剂和溶液充分接触；b) separation of the two phases;18、两相的分离；c)removal移除and recovery恢复of solute溶质from the extract phase萃取相;19、萃取液中溶质的分离和恢复；d)removal and recovery of solvent from each phase, usually by distillation.20、各相中溶剂的分离和恢复，常用精馏的方法。
Contacting may be accomplished in any of the several types of equipment, such as baffle-plate mixers板式搅拌器, mixers混合器which employ impinging撞击jets喷射of the two liquid streams, agitated vessels搅拌容器containing the liquids, plate columns, packed tower, or centrifugal contactor离心接触器.21、接触可以在几种设备中的任一设备中进行，如板式搅拌器，带有两个液体喷射装置的混合器，板式塔，填料塔，或是离心混合器。
Separation may be accomplished by simple settling tanks沉淀槽or by means of centrifuges.22、通过简单的沉淀槽或是离心的手段也可以进行分离。
The dif f iculty encountered in separating the phases is usually greatest when the phases are dispersed分散to a high degree in the contacting equipment接触设备6.23、当各相在接触设备中高度分散时，在进行各相的分离通常是十分困难的。