湿法冶金中锌的萃取工艺研究进展

本文主要综述了国内外近些年对锌萃取的大量基础性研究,对不同种类的锌萃取剂进行了简要介绍。介绍了近些年热点研究的新的萃取工艺和萃取技术。并对工业上不同的锌的原料的萃取过程和方法进行介绍了相关介绍。对锌萃取工艺的工业应用前景进行了评述。     

磷酸三丁酯（TBP）从氯介质中萃取锌的研究

本文研究了磷酸三丁酯(tBP)从氯介质中萃取分离锌的行为和反应的机理,探讨了各种氯盐对锌萃取率的影响。实验表明盐析效应随金属离子的电荷密度的增大而增强。实验中还发现TBP从稀盐酸溶液中萃取的能力比从各种氯盐溶液的锌萃取率大得多,这是由于当溶液中的酸度达到一定值后([HCI]>0.1mol/l),溶液中形成可萃取的锌的络酸形式络合物HZnCl_3或H_2ZnCl_4等。TBP从氯介质中萃取锌的反应属中性络合萃取机理。     

镀锌层退镀液的处理技术研究

本文研究了用Ｎ５０３－煤油体系回收镀锌层退镀液中锌的工艺条件，并进行了实验室三级逆流串级逆流串级模拟实验，结果表明，含锌４０～６０ｇ／Ｌ的退镀液（不需任何处理），直接用Ｎ５０３－煤油作为有机相经三级萃取后，锌的回收率可达９９．９５％。＊萃余泫中剩余锌２０～３０ｍｇ／Ｌ）萃取机理研究表明：锌以络合酸Ｈ２ＺｎＣｌ４形式进同相，其萃合物的溶剂化数为２。     

从氯化浸出液中分离锌与镉的萃取剂选择和评价

本文选择最有工业应用价值的萃取剂,研究了它们从氧化钠溶液中萃取大量的锌与镉的萃取平衡。结果认为中性络合萃取剂对锌具有选择性;而在锌和铁不存在的条件下,阴离子交换萃取剂可选择性地萃取镉。还讨论了络合物的稳定常数在萃取剂选择与评价中的指导作用。     

萃取光度法测定发光材料中杂质锌的含量

着重介绍了硫化锌发光材料中微量杂质锌的测定方法－萃取光度法，采用打萨宗的四氯化碳溶液为螯合剂，以硫代硫酸盐为掩蔽剂，严格控制溶液的酸度。结果表明，萃取光度法能给出满意的测定结果。     

草酸的溶剂萃取研究

实验中首先考察了几种常用萃取剂对草酸、氯乙酸、二氯乙酸、三氯乙酸、轻基乙酸的萃取分配比，依实验结果，选择ＴＢＰ作草酸的萃取剂，可达到草酸与羟基乙酸分离的目的。当萃取剂组成为５０％ＴＢＰ－５０％磺化煤油时，萃取反应过程的热效应为－１８．５ＫＪ／ｍｏｌ，据此确定了萃取过程应在室温下进行。由草酸萃取等温平衡线，求得２２℃下萃取过程理论级数为４级。     

低浓度醋酸水溶液的回收

通过三脂肪胺－煤油－正癸醇体系萃取低浓醋酸水溶液的实验，比较了萃取剂三种成分的不同酸比以及温度对分配系数的影响，确定了萃取操作的最佳萃取剂配比及适宜操作温度。通过静态混合器对萃取过程的强化及减压精馏回收萃取剂实验，验证了三脂肪胺－煤油－正癸醇体系萃取低浓醋酸的工业可行性。     

非等温萃取过程的研究

本文设计了一种非等温萃取过程,并在小型实验装置上对三种体系进行了萃取实验。同时也进行了与之对比的普通液液萃取实验。实验表明,对于本文研究的三种萃取体系,在相同设备和相同操作条件下,非等温萃取过程的分离效果明显高于普通液液萃取过程。     

P204液膜体系分离和富集Fe^3＋的传质机理

通过萃取－反萃取实验确定了Ｐ２０４液膜体系萃取和反萃取Ｆｅ３＋的化学方程式，从而确定了该液膜体系的传质机理。     

异戊醇从氧化物-磷酸体系中萃取磷酸的动力学研究

采用上升液滴法研究了异戊醇从氯化物－磷酸体系中萃取磷酸的动力学，结果表明磷酸的初始正向萃取速率随两相界面积、水相初始磷酸、盐酸浓度的增大而增大，异戊醇对磷酸的萃取可能属扩散控制模式。在实验基础上建立了如下的萃取动力学方程：Ｒｐ＝４．７１９×１０－８Ｃ１．８０２ｐＣ１．００４ｃｌ，其计算值与实验值的相对标准偏差为５．０２％。     

The rate of zinc deposition at zinc Amalgam and zinc metal

The reduction of Zn²⁺ ions in KCl (pH 3.0) has been investigated at Hg, Zn(Hg) and solid Zn. A reaction scheme is suggested by analogy with Cu(su2+) reduction     

Comparative electrochemical studies of zinc chromate and zinc phosphate as corrosion inhibitors for zinc

The anticorrosive performance of two inhibitive pigments, zinc chromate and zinc phosphate, was compared using electrochemical impedance spectroscopy (EIS) and the scanning vibrating electrode technique (SVET) in pigment extracts in 0.1 M NaCl. It was observed that zinc was protected from corrosion in both extracts. In tests using hot dip galvanised steel painted with an epoxy primer incorporating the pigments, the SVET detected the anodic and cathodic distribution along the scribes, although no significant differences were observed among the various primers. On the contrary, EIS was able to distinguish processes occurring on the metal surface exposed by the scribe in different samples. For primers with anticorrosive pigment, a time constant at high frequencies was attributed to a layer of protective nature, probably formed by metal ions from the substrate and inhibitive ions leached from the anticorrosive pigments.     

用锌渣制备高纯氧化锌

介绍了利用锌渣为原料生产高纯氧化锌的方法。采用黄铁矾法除去大部分铁，通过控制ｐＨ值进一步除铁，用锌粉或锌屑还原除去重金属，用氨水为沉淀剂，最终可使氧化锌的含量达９９．８６％以上。     

电镀锌及锌合金发展现状

综述了近年来锌电镀、锌舍金电镀、锌基复合电镀、锌合金基复合电镀的研究与应用现状，并对纳米技术在锌及锌合金电镀中的应用提出了展望。     

锌灰制备碱式碳酸锌和超细氧化锌及表征

室温下采用氨浸出锌灰制得碱式碳酸锌,再经煅烧制得超细氧化锌。研究了在合成碱式碳酸锌过程中表面活性剂对碱式碳酸锌和氧化锌颗粒尺寸与形貌的影响。结果表明,聚乙二醇（PEG20000）和聚乙烯吡咯烷酮（PVP-K30）这两种表面活性剂对颗粒的分散效果最好,制得的碱式碳酸锌颗粒为无定形片状且分散均匀,平均粒径为1 μm,煅烧后的氧化锌颗粒为六方晶系纤锌矿结构,粒径约为0.7 μm。添加PVP-K30比添加PEG20000的碱式碳酸锌热分解温度高。添加PEG和PVP的碱式碳酸锌反应活化能分别为139.9 kJ/mol和146.8 kJ/mol。     

Growth of zinc dendrites in acidic zinc chloride solutions

The heights and widths of zinc dendrites were measured in pure zinc chloride solutions in the concentration and pH range prevailing in zinc-halogen load leveling batteries.At constant overpotential the height increases linearly with time, indicating a constant growth rate. The higher the concentration and the overpotential, the faster is the growth. The critical overpotential for initiation of dendrite growth is 14 mV independent on the concentration. The growth rate increases when the pH decreases. The influence of hydrogen gas evolved at low pH on the growth rate is discussed. Propagation rate is discussed in terms of an extended Barton-Bockris model. When the height of the dendrite is smaller than the diffusion layer thickness, mass transport to the tip is linear and the dendrite propagates in an exponential manner. When the height is larger than the diffusion layer, mass transport to the tip is spherical and the propagation is linear with time. At constant overpotential the widht is a linear function of the square root of the height, indicating that the dendrite has a shape which is preserved during the growth and the tip radius is maintained constant as predicted by the theory.     

Electrodeposition of zinc from high acid zinc chloride solutions

Electrowinning of zinc from zinc chloride solutions, acidified by HCl, was conducted in a cation exchange membrane cell. The current efficiency was correlated with the deposit morphology. The deposits having lesser surface defects, which act as active sites for hydrogen adsorption, exhibited higher current efficiency. The (1 1 0) preferred texture was observed on the deposits grown in high acid solution containing gelatin. High temperature (40 ºC) and high current density decreased the current efficiency and the preferred texture.     

The electrodeposition of zinc from acidified zinc sulphate solution

In the electrodeposition of zinc from acidified zinc sulphate solutions the loss in current efficiency (CE) due to evolution of hydrogen at the cathode has often been attributed to the presence of metal impurities, and it has been thought that in a pure solution the CE would be 100%. In this paper it is argued that, whatever the degree of purity achieved, hydrogen must always be produced simultaneously with zinc. At the start of electrolysis the CE is determined solely by the zinc/acid ratio, but when impurities are present the CE falls progressively as electrodeposition proceeds. Further, colloid silica which is always present in plant solutions is not responsible for the CE falling below 100%, nor are the lead anodes that are used in practice. Some effects of manganese, both at the anode and the cathode, are reported. The deleterious influences of cobalt and manganese together are also discussed.     

Relative yield and zinc uptake by rice from zinc sulphate and zinc oxide coatings onto urea

Zinc (Zn) deficiency is prevalent worldwide and is a barrier to achieving yield goals in crops. It is also now recognized as a leading risk factor for disease in humans in developing countries. In general, soil application of 5–17 kg of Zn ha⁻¹ year⁻¹ as zinc sulphate (ZnSO₄) or more is recommended. However, in developing rice growing countries of Asia, ZnSO₄ of desired quality is not readily available and is also quite expensive, so the farmers generally fail to apply Zn, resulting in rice crop yield loss. Availability of Zn-coated urea guarantees not only the availability of quality Zn but also ensures its application. Field experiments were therefore conducted during the rice seasons of 2005 and 2006 at the Indian Agricultural Research Institute, New Delhi, to evaluate the relative efficiency of 0.5, 1.0, 1.5 and 2.0% Zn as ZnSO₄- or zinc oxide (ZnO)-coated ureas for rice. Soil application of ZnSO₄ was also compared in 2006. Rice grain and straw yields, Zn concentrations in grain and straw, and Zn uptake by rice increased with the level of Zn coating onto urea. Crop response was the highest with 2.0% ZnSO₄-coated urea, and higher than with the same rate of ZnO-coated urea, possibly related to the higher water solubility of Zn in ZnSO₄. Crop response with ZnSO₄-coated urea was also higher than with the same rate of ZnSO₄ and urea applied separately to the soil. However, apparent recovery data suggest that 1.0% coating with ZnSO₄ may be a better choice from the point of view of the utilization of applied Zn. Increased Zn concentrations in rice grain due to application of Zn-coated urea is important from the point of view of Zn nutrition of humans, since rice is the staple food in developing countries of Asia. Also, increased Zn concentrations in rice straw is of importance as regards cattle nutrition since in developing countries of Asia rice straw is the major feed for farm cattle.     

电镀锌及锌合金的智能数字化生产

根据清洁生产的要求,从电镀设备、电镀工艺以及工厂管理等方面,阐述了如何实现电镀锌及锌合金的智能数字化生产.列出了各工序所需的辅助设备,说明了滚、挂镀锌自动生产线的布置(包括前处理及后处理),介绍了自动生产线日常管理的方法(包括对人员、设备、材料和槽液的管理).