从硫化矿高酸浸出的硫酸锌溶液中萃取提锗全流程研究

研究在硫酸锌溶液中用萃取法提取锗,萃取剂为7815(氧肟酸),稀释剂为磺化煤油,添加剂为T试剂,反萃剂为NaOH,原料液为云南会泽铅锌矿硫化锌高温、高酸、高铁浸出溶液;工艺就萃取体系的选择,金属的萃取平衡,工艺参数的确定,工艺流程的设计以及工艺流程的串级实验等进行了深入研究,取得了锗萃取率大于96%,反萃率大于97%,锗精矿含锗大于30%的结果。     

N-正丁基异辛酰胺和磷酸三丁酯的萃铂性能对比研究

溶剂萃取技术已被广泛应用于回收和分离提纯铂族金属。磷酸三丁酯(TBP)萃取分离铂成功地应用于失效汽车催化剂富集精矿溶解液中铂的萃取分离。分别用N-正丁基异辛酰胺(BiOA)和磷酸三丁酯(TBP)作为萃取剂,研究了对铂废料电解液中铂的萃取性能。N-正丁基异辛酰胺(BiOA)的一级萃取率高达99.85%、萃取容量达20.1 g/L、用水作反萃剂的累计二级反萃率达99.5%;磷酸三丁酯(TBP)的一级萃取率达99.2%、萃取容量达16.5 g/L、用水作反萃剂的累计二级反萃率在50%左右。BiOA萃铂体系在以上3方面的性能优于TBP萃铂体系,但还需进一步做更多更深入的研究,探寻BiOA萃铂体系的工业化应用可能。     

同级萃取反萃膜过程的研究

本文研究了同级萃取反萃膜过程的传质性能。使用的膜器是一种特制的中空纤维膜器。实验中采用了三种不同的体系,反萃液为10%NaOH和清水。本文建立了同级萃取反萃膜过程传质模型,模型计算值与实验测定的总传质系数值相吻合。10%NaOH膜反萃的加入明显提高了过程的分离效率。     

同级萃取反萃膜过程的研究

本文研究了同级萃取反萃膜过程的传质性能。使用的膜器是一种特制的中空纤维膜器。实验中采用了三种不同的体系,反萃液为10%NaOH和清水。本文建立了同级萃取反萃膜过程传质模型,模型计算值与实验测定的总传质糸数值相吻合。10%NaOH膜反萃的加入明显提高了过程的分离效率。     

P_(204)与C_(5-7)羟肟酸液膜体系自湿法冶锌系统中同步迁移分别回收镓和锗(Ⅱ

提出了乳状液膜体系自湿法冶锌系统中经一级同时分离镓和锗的新方法,建立了用 Ｐ２０４和 Ｃ５ － ７ 羟肟酸协同载体,ｐ Ｈ＝ ３ ．２ 的 Ｎ Ｈ４ Ｆ 溶液为内水相试剂,使 Ｇｅ４ ＋ 以溶液状态而 Ｇａ３ ＋ 则以 Ｇａ（ Ｏ Ｈ）３ 沉淀同步迁移进入内水相并分别回收的液膜体系,研究了影响 Ｇａ３ ＋ 、 Ｇｅ４ ＋ 迁移的各种因素,经正交实验确定了分离镓和锗的最佳液膜组成及操作条件,并用加入铁粉法除去了杂质 Ｆｅ３ ＋和 Ｃｕ２ ＋ 对 Ｇａ３ ＋ 、 Ｇｅ４ ＋ 迁移的干扰．所得镓和锗的回收率分别为９４ ．７ ％ 和９８ ．６ ％ ,纯度为９７ ．８ ％ 和９６ ．３ ％ ． Ｚｎ２ ＋ 离子损失仅２ ．１５ ％ ,回收镓和锗后的萃余液可返回冶锌系统．     

N-正丁基异辛酰胺对铂的萃取性能研究

溶剂萃取技术已被广泛应用于回收和分离提纯铂族金属。随着新萃取剂和新萃取体系的研究开发,贵金属萃取技术研究不断取得新的进展。用N-正丁基异辛酰胺(BiOA)作为萃取剂,研究对铂废料电解液中铂的萃取性能。在合适的萃取条件下,即酸度为4 mol/L、萃取剂浓度为2 mol/L,相改善剂磷酸三丁酯(TBP)的加入量为3vol%,萃取率达99.5%以上;用水作反萃剂,反萃率达99.2%以上。铂反萃液,通过常规的水合肼还原的方法,即可获得99.95%纯度的海绵铂。该萃取体系高效、环保,具有工业化的应用价值。     

微乳液-中空纤维膜萃取钕的工艺研究

提出了一种新的膜分离过程即非离子W/O型微乳液-中空纤维膜萃取,所用非离子型微乳液体系为(OP-7 OP-4)/苯甲醇/D2EHPA/煤油/盐酸.在不同微乳液流速、料液流速、微乳液内相盐酸浓度、料液浓度、以及不同中空纤维膜数等条件下进行了微乳液-中空纤维膜逆流萃取Nd3 的研究.结果表明,微乳液和料液流速越小,萃取率越高,内相富集倍数越大.微乳液内相盐酸浓度越大,萃取率越高,但富集倍数反而减小.料液初始浓度越小,萃取率和富集倍数越大.当微乳液流速为6 mL/min、料液与微乳液流速比为3∶1、微乳液内相盐酸浓度为4 mol/L、料液浓度为200 mg/L时,经过微乳液在三个中空纤维膜萃取器中的串联萃取,Nd3 的萃取率达96.3%,内相Nd3 浓度为4238 mg/L,是萃余料液浓度的572.7倍,内相富集倍数为21.2.膜萃取过程与膜溶剂萃取相比对Nd3 有更高的萃取效率.     

DBC与MSO从碱性氰化液中协同萃取金的研究

研究了在用DBC,MSO及DBC-MSO作萃取剂的碱性氰化液中萃取Au(Ⅰ)的性能.考察了萃取剂和助萃剂的浓度、相比、萃取时间等因素对Au(Ⅰ)萃取率的影响以及Na2S2O3反萃金的性能.实验表明,在采用某种助萃剂X助的作用下,DBC-MSO体系从碱性氰化液中萃取金的协萃效应较高.在整个组成范围内,协萃系数R均大于1.助萃剂X助对DBC-MSO体系萃金的影响较大,但X助本身不萃金.DBC-MSO体系能快速萃取金,在1 min内已基本达到萃取平衡.DBC-MSO协萃体系有望能成为碱性氰化液中萃取金的一项新技术.     

使用支撑液膜从Fe^3＋／Cu^2＋溶液中选择分离Fe^3＋的研究（I）液液萃取实验

支撑液膜在水溶液金属离子的分离中有着独特的优势。报道了从Fe^3 ／Cu^2 溶液中选择分离Fe^3 液／液萃取研究结果。水相为Fe^3 ／Cu^2 硫酸溶液,萃取相为正癸醇（n-de-canol）,载体为二（2－乙基己基）磷酸（D2EHPA）。实验研究了溶液相中硫酸浓度以及有机相中载体D2EHPA浓度金属离子萃取速率的影响。研究发现水溶液的酸浓度对Fe^3 的萃取影响较明显,而对Cu^2 的萃取影响很小。在两相界面处Fe^3 与D2EHPA的反应速度比Cu^2 快很多。Fe^3 、Cu^2 与D2EHPA的络合物在有机相中的扩散速度都较慢,但是Fe^3 与D2EHPA的络合物的界面反应速度比络合物的扩散速度快。有机相中载体浓度对金属离子萃取速率的影响也很明显。液液萃取研究结果显示,在使用支撑液膜进行铁离子选择分离时,可以通过改变溶液相酸的浓度,有机相中载体浓度,或者通过缩短分离时间来提高选择率。     

膜萃取过程及其进展

膜萃取过程是一种新型的分离技术。与通常的溶剂萃取过程不同,膜萃取过程中没有相分散行为发生。该过程具有一些区别于通常萃取过程的特殊优势。本文较详细地介绍了膜萃取过程的研究和进展情况。     

Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin

Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 degrees C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results.     

Liquid membrane operations in a microfluidic device for selective separation of metal ions

A three-phase flow, water/n-heptane/water, was constructed in a microchannel (100-microm width, 25-microm depth) on a glass microchip (3 cm x 7 cm) and was used as a liquid membrane for separation of metal ions. Surface modification of the microchannel by octadecylsilane groups induced spontaneous phase separation of the three-phase flow in the microfluidic device, which allows control of interfacial contact time and off-chip analysis using conventional analytical apparatus. Prior to the selective transport of a metal ion through the liquid membrane in the microchannel, the forward and backward extraction of yttrium and zinc ions was investigated in a two-phase flow on a microfluidic device using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (commercial name, PC-88A) as an extractant. The extraction conditions (contact time of the two phases, pH, extractant concentration) in the microfluidic device were examined. These investigations demonstrated that the conventional methodology for solvent extraction of metal ions is applicable to solvent extraction in a microchannel. Finally, we employed the three-phase flow in the microchannel as a liquid membrane and observed the selective transport of Y ion through the liquid membrane. In the present study, we succeeded, for the first time, in the selective separation of a targeted metal ion from an aqueous feed solution to a receiving phase within a few seconds by employing a liquid membrane formed in a microfluidic device.     

异相共混螯合滤膜的制备及其性能研究

通过探讨共混比例、螯合树脂粒径、PSF（聚砜）浓度及制膜液温度对膜性能的影响,用相转换法制备出对Cu^2＋具有大螯合容量的D418树脂／聚砜异相共混螯合滤膜。研究了膜对Cu^2 的吸附及盐溶液pH值和盐浓度对螯合容量的影响。对膜进行动态螯合吸附测试表明该膜对Cu^2 可实现萃取与反萃取同级进行。     

Non-self-maintained dischange plasma treatment of aqueous heavy-metal solutions

An electrochemical system is studied in which one electrode is in the vapor phase over a liquid surface and the other is under the liquid surface, and a non-self-maintained glow discharge initiated by a subsidiary discharge burns between the upper electrode and the liquid surface. It is shown that in this system ions of heavy metal compounds are released from solution within a relatively thin near-surface layer of the solution. Conditions are found under which the efficiency of plasma chemical extraction of metals from the solutions is several times higher in comparison with the electrochemical method.     

亚胺基二乙酸型螯合树脂应用研究进展与展望

亚胺基二乙酸型(IDA)螯合树脂及其配合物因具有优异的吸附性能和物化性质,近年来成为研究的热点。介绍了IDA螯合树脂的常用制备方法,总结了树脂的螯合吸附机理、影响机制、吸附的模型及吸附动力学。重点综述了IDA螯合树脂在金属离子的提取富集、工业废水处理及饮用水净化除杂、分析化学检测方面的国内外应用研究进展,及其配合物在有机反应中作催化剂、对有机物分离和纯化、吸附气体中有害成分方面的应用。最后,对IDA螯合树脂的制备改进方向、未来研究应用领域进行了展望。     

Separation and recovery of critical metal ions using ionic liquids

Separation and purification of critical metal ions such as rare-earth elements (REEs), scandium and niobium from their minerals is difficult and often determines if extraction is economically and environmentally feasible. Solvent extraction is a commonly used metal-ion separation process, usually favored because of its simplicity, speed and wide scope, which is why it is often employed for separating trace metals from their minerals. However, the types of solvents widely used for the recovery of metal ions have adverse environmental impact. Alternatives to solvent extraction have been explored and advances in separation technologies have shown commercial establishment of liquid membranes as an alternative to conventional solvent extraction for the recovery of metals and other valuable materials. Liquid membrane transport incorporates solvent extraction and membrane separation in one continuously operating system. Both methods conventionally use solvents that are harmful to the environment, however, the introduction of ionic liquids (ILs) over the last decade is set to minimize the environmental impact of both solvent extraction and liquid membrane separation processes. ILs are a family of organic molten salts with low or negligible vapour pressure which may be formed below 100 ℃. Such liquids are also highly thermally stable and less toxic. Their ionic structure makes them thermodynamically favorable solvents for the extraction of metallic ions. The main aim of this article is to review the current achievements in the separation of REE, scandium, niobium and vanadium from their minerals, using ILs in either solvent extraction or liquid membrane processes. The mechanism of separation using ILs is discussed and the engineering constraints to their application are identified.     

Integrated copper-containing wastewater treatment using xanthate process

Although, the xanthate process has been shown to be an effective method for heavy metal removal from contaminated water, a heavy metal contaminated residual sludge is produced by the treatment process and the metal-xanthate sludge must be handled in accordance with the Taiwan EPA's waste disposal requirements. This work employed potassium ethyl xanthate (KEX) to remove copper ions from wastewater. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) were used to determine the leaching potential and stability characteristics of the residual copper xanthate (Cu-EX) complexes. Results from metal removal experiments showed that KEX was suitable for the treatment of copper-containing wastewater over a wide copper concentration range (50, 100, 500, and 1000 mg/l) to the level that meets the Taiwan EPA's effluent regulations (3mg/l). The TCLP results of the residual Cu-EX complexes could meet the current regulations and thus the Cu-EX complexes could be treated as a non-hazardous material. Besides, the results of SDLT indicated that the complexes exhibited an excellent performance for stabilizing metals under acidic conditions, even slight chemical changes of the complexes occurred during extraction. The xanthate process, mixing KEX with copper-bearing solution to form Cu-EX precipitates, offered a comprehensive strategy for solving both copper-containing wastewater problems and subsequent sludge disposal requirements.     

Permeation liquid membrane metal transport: studies of complex stoichiometries and reactions in Cu(II) extraction with the mixture 22DD-laurate in toluene/phenylhexane

The role of lauric acid (LAH) in the transport of copper(II) through a permeation liquid membrane (PLM) comprising 1,10-didecyldiaza-18-crown-6 (22DD) and lauric acid (ratio 1:1) in 1:1 v/v toluene/phenylhexane has been investigated by determining the stoichiometry of metal extraction and of the metal complex formed in the organic phase by performing 1H NMR and liquid/liquid and liquid/membrane extraction measurements. In the absence of copper(II), the 1H NMR data suggest that there is a strong interaction between the proton of LAH and the nitrogen of the 22DD macrocycle but no interaction between the aliphatic long chains of LAH and 22DD. Thus, in the organic solution, the two compounds are associated as (22DD-H)(+)-LA-, the laurate being away from (22DD-H)+. The signal intensity of the acidic proton was found to decrease when the metal Pb(II) was incorporated by the carrier after its extraction from the aqueous phase. Additionally, liquid/liquid as well as liquid/membrane extraction results reveal that Cu(II) extraction proceeds via the loss of two protons from the organic phase. The Cu(II) is found to be located in the 22DD cavity and the stoichiometry of the complex in the organic phase is (22DD-Cu)(2+)-2LA-. Metal extraction is governed by 22DD and laurate acts only as counteranion. An unexpected feature was observed in the liquid/liquid extraction which was that, at low 22DD and LAH concentrations, the slope for log(Kp) = f(pH) was 2 whereas it was much lower at high carrier concentration. This unexpected result seems to stem from impurities present in 22DD: only 0.1 mol% of impurity can indeed influence the exchange ratio of Cu(II) and H+. This type of anomaly, however, is not found in the normal procedure of liquid/membrane extraction possibly due to the lower carrier/metal molar ratio which is used in the classical PLM conditions.     

Modified softwood sawdust as adsorbent of heavy metal ions from water

The sawdust of deciduous softwood-poplar, and coniferous softwood-fir, have been found to possess some adsorption capacities for heavy metal ions. Their adsorption capacities can be increased by previous treatment with a sodium hydroxide solution. Adsorption capacities of alkali modified adsorbents were higher than for unmodified ones from 2.5 to 5 times for copper ions, and about 15 times for zinc ions. Also, for modification can be used solution of sodium carbonate, but that alkaline solution is less efficient than sodium hydroxide solution. The 1% sodium hydroxide solution is suggested for modification of softwood sawdust. It was established that the ion exchange is not only adsorption mechanism, than microprecipitation of metal-hydroxide in the pore liquid was happened, too. At the same time, the leaching of organic matters from modified softwood sawdust were less than from unmodified ones for about 7% for poplar and 23% for fir.     

Optimization of process parameters for the extraction of chromium (VI) by emulsion liquid membrane using response surface methodology

The emulsion liquid membrane technique was used for the extraction of hexavalent chromium ions from aqueous solution of waste sodium dichromate recovered from the pharmaceutical industry wastewater. The liquid membrane used was composed of kerosene oil as the solvent, Span-80 as the surfactant and potassium hydroxide as internal reagent. Trioctyl amine and Aliquat-336 were used as carriers. The emulsion stability was carried out at different surfactant concentration, agitation speed and emulsification time. Statistical experimental design was applied for the optimization of process parameters for the extraction of chromium by emulsion liquid membrane. The effects of process parameters namely, agitation speed, membrane to emulsion (M/E) ratio and carrier concentration on the extraction of chromium were optimized using a response surface method. The optimum conditions for the extraction of chromium (VI) using response surface methodology for Trioctyl amine were: agitation speed – 201.369 rpm, M/E ratio – 0.5887% (v/v) and carrier concentration – 4.0932% (v/v) and for Aliquat-336: agitation speed – 202.097 rpm, M/E ratio – 0.5873% (v/v) and carrier concentration – 3.9211% (v/v). At the optimized condition the maximum chromium extraction was found to be 89.2% and 96.15% using Trioctyl amine and Aliquat-336, respectively.