Total concentration of main components in solutions for metal electroplating as a criterion for classifying and choosing resource-saving compositions of solutions

A comparative analysis is performed of the variations in the total concentration of the main components $\left( {\sum\limits_i {c_i } } \right)$ , in the solutions proposed and used in different years for electroplating individual metals (Cr, Cu, Ni, Zn, Sn, Cd, Pb, and Fe). A quantitative concentration criterion is determined for classifying solutions into resource-saving ( $\left( {\sum\limits_i {c_i \leqslant 2.32} } \right)$ mol-equiv/L) and resourceintensive ( $\left( {\sum\limits_i {c_i \geqslant 2.78} } \right)$ mol-equiv/L) compositions. In addition to scientific interest, this material can be useful for developing studies aimed at reducing the negative environmental impact of electroplating shops or sections.     

电镀废水中重金属处理方法

介绍了电镀废水中重金属处理的3种方法:中和沉淀法、硫化物沉淀法及螯合物沉淀法。讨论了中和沉淀法和硫化物沉淀法的优点及存在的问题,并给出了解决方法。螯合物沉淀法有待进一步研究。     

Prediction of metal distribution in electroplating systems

Three methods of approximation were developed to predict the metal distribution in electroplating systems. The results were compared with Watson's experimental data for the Watts-nickel (close to 100% current efficiency), tin-nickel (alloy deposition, also close to 100% current efficiency), and the standard chromium (approximately 20% current efficiency) systems. Method 1 predicted too uniform a distribution whereas Methods 2 and 3 showed good agreements with all three systems. The same experimental data were also used to evaluate three predictive methods frequently used in the literature. The primary current distribution and an empirical formula by Hull were found to be inadequate in describing these systems. The secondary current distribution which involved a great deal of numerical analysis showed a considerable improvement.     

连二硫酸金属盐和连二硫酸在电镀和金属精饰领域的应用

在电镀溶液中使用连二硫酸和连二硫酸金属盐作为可溶性金属离子和电解质的来源具有潜在的应用。为有助于具有创新精神的配方研究者考虑采用诸如连二硫酸这种新型电解质,文章总结了连二硫酸盐电镀液近期的发展,用实例说明了连二硫酸盐在电镀液中的应用。众所周知,连二硫酸在强酸溶液中发生歧化反应,但这并不妨碍在适宜的条件下使用连二硫酸盐以及连二硫酸。(由于篇幅限制,有关连二硫酸及连二硫酸金属盐的化学性质、稳定性、制备方法等补充材料及学术综述、研究报告所涉及的参考文献均在本刊网站上详细全文发表,见http:／／www．plating．org／web／20060901．mht。)     

无铅纯锡电镀晶须产生的原因和控制对策

开发无铅化纯锡电镀技术必须首先解决锡须问题。讨论了锡须形成的影响因素及机理。开发出一种能有效防止锡须生成的无铅纯锡电镀添加剂,该添加剂具有结晶细致、可焊性好、消耗量低、使用维护容易等优点,从而建立了一种抑制锡须的有效方法,同时解决了纯锡电镀中的其它难题。介绍了控制锡须的其它一些有效措施及锡须生长加速试验。     

环保锌中金属杂质的秘密

第一次听到“环保锌”是在上世纪90年代一次中国国际表面处理展览会上,当时觉得挺新奇,也不知是啥玩意,好在还安排外国专家举办讲座,我求之不得,准时赴会。     

电镀酸锡废水中不同金属离子的分离工艺

利用各种金属离子形成氢氧化物沉淀时pH的不同,从而实现电镀酸锡废水中各金属离子的分离与回收。原废水的pH为0.45,其中含锡137.3mg/L、Ni46.1mg/L、Fe11.4mg/L、Co8.6mg/L。先用10%的氢氧化钠溶液调节废水的pH为4.7,废水中的锡元素形成氢氧化亚锡沉淀;分离锡元素后的废水用10%的双氧水把其中的亚铁完全氧化成三价铁,再调节废水的pH至4.1,以除去铁元素;在分离了铁元素的废水中加入10%的次氯酸钠溶液,把其中的二价钴完全转化成三价钴,再调节废水pH为5~6,以分离钴元素;调节除钴后废水的pH为9.5沉淀其中的镍元素。     

电镀集中区电镀废水的处理

废水处理是电镀集中区建设成功的关键.提出了搞好电镀集中区中电镀废水处理的一些前提与方法:首先要按清洁生产的要求对入驻集中区的企业进行审核,同时要认真剖析集中区内电镀废水的特点,运用循环经济的理念对不同电镀废水进行分类收集,采用最佳的废水处理技术,并根据"集散控制模式"进行处理,以达到回用废水及回收废水中有价值的重金属的理想效果.对各种先进的处理技术(包括化学法、膜分离技术、螯合沉淀法、HR型除铬机、生化法和高压脉冲电凝加硅藻土整合技术)进行了对比.推荐采用国外某公司的重金属捕捉剂.     

Stabilization of UV-curable vinyl compositions by transition metal compounds

A UV-curable composition, which has a shelf life of greater than six months at 60°C for bonding or coating glass surfaces, was developed. The formulation consists of a dimethacrylate monomer, a methacryltrialkoxysilane, a photoinitiator, MEHQ, DLTDP, a water scavenger, and FeCl₃. In the absence of FeCl₃, gelation occurs within 24 hr at 25°C. Gelation is caused by the formation of a crosslinked vinyl addition polymer having a methacrylate diester/silane monoester mole ratio of 20:3. Analogous stability is achieved if instead of FeCl₃ a number of heavy metal compounds are used, including CrCl₃, CoCl₂, NiCl₂, RuCl₃, Pr(fod)₃, and Eu(fod)₃. Nontransition metal compounds, e.g., AlCl₃, BCl₃, and SnCl₂, are poor or ineffective stabilizers. Gelation is initiated by free radicals. When MEHQ and DLTDP are present, less Fe³⁺ is converted to Fe²⁺ than in their absence. This indicates that a complex interaction is operating among these substances. A scheme is presented in which recycling of Fe³⁺ and phenolic and thioether antioxidants is proposed.     

生化法去除电镀废水中重金属离子的研究

利用从重金属污染物中筛选出的混合菌种进行重金属离子的去除。实验考察了pH、菌种投加量、温度及反应时间对混合菌种去除重金属离子的影响,并通过正交实验对影响因素进行了优化。确定其最佳的处理条件为:pH=6.0,反应时间20min,微生物投加量3.0mL/L和温度20℃,并在此条件下进行了实际电镀废水的验证实验。结果表明:混合菌群在最佳条件下对实际电镀废水中的镉、铬、铜和镍离子的去除率分别为97.7%、98.6%、95.0%和91.5%,效果良好。     

Concentration dependence of the morphology of electrodeposits and a criterion for the morphological change of copper electrodeposits

The morphology of copper electrodeposits from acidic copper sulphate solution was studied at various copper sulphate concentrations and at relatively low overpotentials. The morphology at the various concentrations was not affected much by the current density, but rather by the overpotential. The evolution of 3-D nuclei was found to be a possible cause of the morphological change, since the critical overpotential for the evolution had a nearly constant value despite the concentration change. Unfortunately, a quantitative explanation of the data are not yet possible.     

A resource-saving technology for manufacturing unfired articles for bottom casting of steel

Basic parameters of a resource-saving technology for manufacturing unfired articles for bottom steel casting that was developed under laboratory conditions are presented. Industrial tests of an experimental batch of unfired bottom tubes produced by the suggested technology have shown high performance properties for them and applicability of them for bottom casting of steel.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 8, pp. 27–29, August, 1996.     

热泵和太阳能在电镀废液处理与回用中的应用

介绍了一种新型的电镀化工废液蒸发浓缩回用系统.该系统采用专利技术的聚丙烯减压蒸发器,以高温水源热泵和太阳能集热系统作为加热能源,实现能源和物料的全循环回收.比较了该系统与燃油、燃煤锅炉以及电加热系统的能耗,分析了某电镀厂采用该系统处理氰化镀铜、氰化镀银、氰化镀金及镀镍废液一个月所取得的效益.实践证明,该系统运行成本低、无污染,产生的经济效益明显.     

电镀用滤芯的现状

电镀用滤芯可分为表面过滤型和深层过滤型2种.介绍了线绕滤芯和活性炭滤芯的过滤原理、特点及选用标准.     

FeS流化床处理电镀废水中重金属离子的试验研究

针对我国电镀行业厂点多、规模小及电镀污染治理水平低等特点.设计了内循环式流化床,利用廉价易得的FeS来处理含铬、铜、锌和镉的混合电镀废水,论述了FeS投加量、水力停留时间、FeS的粒度以及曝气量等工艺参数对FeS流化床处理效率的影响;一定反应条件下对电镀废水中重金属离子的去除效果;不同重金属离子的去除机理等.     

Study of metal ion sorption from acidic solutions

Acid mine drainage waters flowing out of the abandoned sulphide ore mine Smolnik in Slovakia represent a serious source of water and soils contamination. High concentrations of sulphate, iron, copper and other heavy metals are the result of pyrite oxidation connected with sulphuric acid production, which continuously dissolves rock minerals and produces a number of potentially toxic elements. The paper deals with the utilization of four types of natural and synthetic sorbents (produced mainly in Slovak Republic) for Fe, Cu, Al, Mn and Zn removal from acid mine drainage (shaft Pech, locality Smolnik, Slovakia). Prior to the kinetic study, the screening sorption experiment has been performed in order to determine optimum sorption pH. The turf brush sorbent Peatsorb has shown the satisfactory results for the removal of iron, copper, aluminium, zinc and manganese at pH below 4.