Purification of gadolinium by electrorefining

The electropurification of crude gadolinium, as an alternate method to the distillation process currently used, was studied using a LiCl-LiF-GdF₃ electrolyte. The best results were obtained with a 77.6 wt pct LiCl, 11.2 wt pct LiF, 11.2 wt pct GdF₃ electrolyte at 700‡C. It was shown that the purity of the deposit was strongly dependent on the purity of the electrolyte and the temperature. The purest deposit of Gd was obtained when the LiCl and LiF were purified by distillation and high purity GdF₃ was used. The analyses showed this purest gadolinium is still less pure than the gadolinium prepared by the dis-tillation process. The effect of various methods used to remove the adhering electrolyte salts and to consolidate the deposited dendrites was studied. Removal of the adhering salts by distillation followed by arc and electron beam melting of the dendrites gave the purest Gd. The analyses of the metal prepared under the various conditions are given. HIROSHI NAGAI, formerly a Post-Doctoral Associate, Ames Labo-ratory-DOE, Iowa State University, Ames, IA 50011     

Purification of gadolinium by electrorefining

The electropurification of crude gadolinium, as an alternate method to the distillation process currently used, was studied using a LiCl−LiF−GdF₃ electrolyte. The best results were obtained with a 77.6 wt pct LiCl, 11.2 wt pct LiF, 11.2 wt pct GdF₃ electrolyte at 700°C. It was shown that the purity of the deposit was strongly dependent on the purity of the electrolyte and the temperature. The purest deposit of Gd was obtained when the LiCl and LiF were purified by distillation and high purity GdF₃ was used. The analyses LiCl and LiF were purified by distillation and high purity GdF₃ was used. The analyses showed this purest gadolinium is still less pure than the gadolinium prepared by the distillation process. The effect of various methods used to remove the adhering electrolyte salts and to consolidate the deposited dendrites was studied. Removal of the adhering salts by distillation followed by arc and electron beam melting of the dendrites gave the purest Gd. The analyses of the metal prepared under the various conditions are given. HIROSHI NAGAI, formerly a Post-Doctoral Associate, Ames Laboratory-DOE. Iowa State University, Ames IA 50011.     

脉冲磁场强度对钛处理低碳钢凝固过程的影响

采用自发研制的脉冲磁场发生装置将脉冲磁场非接触式地施加到钛处理低碳钢的凝固过程中,利用金相显微镜、扫描电镜和能谱仪研究了不同强度的脉冲磁场对试样的宏观形貌、枝晶和组织的影响。结果表明,随着脉冲磁场强度的增加,试样的宏观表面逐渐变得平整;枝晶和组织随着脉冲磁场强度的增加逐渐细化,但达到一定强度后,继续增加又出现了相反的结论。由此可以推断,脉冲磁场强度对枝晶和组织的影响存在一个最佳值。     

不同条件下脉冲电流对纯铝凝固组织的细化

在金属凝固的过程中施加脉冲电流是一种有效的细化凝固组织的方法。围绕脉冲电流细化晶粒的机制提出了多种理论。利用纯铝作为研究材料,在脉冲电流参数、浇注温度等工艺参数不变的情况下,设计了两组铸型条件不同的试验,发现不同条件下得到的铸锭凝固组织的特征有所不同。结合结晶雨机制讨论了这些特征的形成原因,指出了熔体的流动情况对脉冲电流细化效果有重大的影响。     

铜电解电耗因素影响分析及研究

通过铜电解工艺理论分析、电解液物理特性试验、工业试验平台测试,研究了铜电解精炼过程电解液电导率对电耗的影响,确定了电解液温度、硫酸浓度、镍离子浓度与电耗的定量关系,根据现有电解液净化工艺流程,提出最佳镍离子浓度值。     

Effect of electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K

The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on discharge capacity and discharge voltage plateau of LaNi5 alloy electrode at 233 K, and the highest discharge capacity and discharge voltage plateau were both obtained at 6 mol/L KOH. When the KOH electrolyte concentration changed from 5 to 9 mol/L at 233 K, the high rate discharge ability (HRD) had the same change tendency as the diffusion coefficient, but the exchange current density did not change significantly, which implied that hydrogen diffusion was the control step at low temperature 233 K for discharge process of LaNi5 alloy electrode.     

基于多重分形研究脉冲磁场周期对凝固组织的影响

为了研究脉冲磁场对凝固组织的影响,采用自发研制的脉冲磁场发生装置将脉冲磁场非接触式地施加到钛处理低碳钢的凝固过程中,利用金相显微镜和实验室设计的多重分形软件研究了不同周期的脉冲磁场对凝固组织的影响。结果表明,该钢种的凝固组织具有分形特征;随着脉冲磁场周期的延长,Δα和Δf(α)呈现为先减小后增大的规律,在脉冲磁场周期为0.5 s时,组织最为均匀。由此可以推断脉冲磁场周期对凝固组织的影响存在一个最佳值。     

Behavior of admixtures in a weakly conducting porous medium with fluids under pulsed pressure excited by an electric discharge

The behaviour of admixtures in a porous medium with fluids under pulsed pressure excited by an electric discharge in surfactant solutions is studied theoretically. A mechanism is revealed for the effect of high-voltage discharges and the mechanical waves excited by them on the behaviour of composite objects (rocks having pores filled with hydrocarbon fluids, i.e. oil and surfactant solution; hard organomineral deposits). A relationship is established for filtration processes in porous materials and oil quality on treatment energy. Features established for the behaviour of composite objects may be effective in creating methods of electric discharge treatment of heterogeneous objects (articles, semifinished products of composite materials) where instead of the deposits of asphalts, resins, paraffins, there may be other admixtures, and instead of the oil and aqueous electrolyte with surfactant there may be other liquids. The results obtained may be used in developing scientific bases for managing the filtration properties of porous materials of different origin (including man-made).     

氧化模板在电子铝箔腐蚀中的应用

通过控制铝多孔氧化膜的孔径及分布,获得了适合铝电解电容器发孔的氧化铝模板;通过减薄阻挡层厚度工艺及腐蚀工艺的调整,获得了孔洞分布均匀的腐蚀箔,为开发高容量节能铝电容器新腐蚀工艺提供了新思路。     

Effect of electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K

The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on discharge capacity and discharge voltage plateau of LaNi5 alloy electrode at 233 K, and the highest discharge capacity and discharge voltage plateau were both obtained at 6 mol/L KOH. When the KOH electrolyte concentration changed from 5 to 9 mol/L at 233 K, the high rate discharge ability （HRD） had the same change tendency as the diffusion coefficient, but the exchange current density did not change significantly, which implied that hydrogen diffusion was the control step at low temperature 233 K for discharge process of LaNi5 alloy electrode.     

熔盐电解法制取钬铁合金试验研究

在氟化物熔盐体系中采用自耗阴极进行氧化物的熔盐电解,通过电解温度、阴极电流密度和熔盐配比等主要技术条件进行正交设计试验,对电解过程中电解质组成、电解温度、阴极电流密度和加料速度等因素对合金成分、稀土收率影响进行了试验研究。获得了较佳的工艺技术条件,为钬铁合金的规模化生产提供了切实可行的途径。     

Electrorefining of a gold-bearing antimony alloy in alkaline xylitol solution

The electrochemical dissolution and electro-deposition of a gold and silver bearing antimony alloy obtained from the smelting of antimony concentrate were investigated in alkaline NaOH/xylitol electrolyte. The results show that the electrochemical antimony dissolution increases with higher temperature, but the relationship between antimony dissolution and NaOH/xylitol/antimony concentration is uncertain. The antimony electro-deposition becomes faster with increasing antimony concentration and temperature，but decreasing xylitol concentration. The effects of NaOH/xylitol/antimony concentration, current density, electrode distance, and electrolyte temperature on the electro-refining of antimony process were studied. Under optimal conditions, the current efficiency was 98.3% and energy consumption was 436.7 kwh/t-Sb. The purity of electrolytic antimony was 99.4% and gold and silver were enriched 8–9 times in the anode slime, therefore providing an effective separation of precious metals from antimony by electrolysis.     

银电解液中有价金属综合回收生产实践

简要介绍了利用火法处理铅阳极泥和脱铜阳极泥生产金银合金,以及金银合金电解的处理过程;阐述了金银合金电解过程中有价金属的走向和银电解液的变化;重点讨论了银电解液中有价金属银、铜、钯的回收试验与生产过程。生产实践表明:沉钯试剂A和沉钯试剂B均能回收银电解液中的钯,前者得到的银粉中钯质量分数符合IC-Ag99.99中0.001%的限量要求,后者得到的银粉中钯质量分数达不到IC-Ag99.99的限量要求;氨水-水合肼还原法回收银,银粉熔铸得到符合要求的IC-Ag99.99产品;铁粉置换法回收铜,得到铜质量分数约55%的富铜渣。钯、银和铜的综合回收使企业获得显著的经济效益。     

Electrowinning copper from solvent extraction acid strip solution using Pb-Sb anodes

Copper electrowinning from solvent extraction acid strip solutions was studied as a part of a more comprehensive laboratory investigation on development of a process for treating native copper ores by ammoniacal leaching-solvent extraction-electrowinning methods. Because initial electrowinning tests resulted in poor quality copper cathodes, a study was undertaken to determine the conditions necessary for producing high-quality electrowon copper before proceeding with other phases of the process development. The electrowinning tests showed that removing entrained organic from the electrolyte, maintaining a protective voltage on the anodes when electrowinning was not in progress, and adding a small amount of cobalt to the electrolyte resulted in production of copper cathodes with a low lead content when using antimonial lead anodes. After satisfying these conditions, large variations in other operating conditions were possible without materially affecting the lead content of the electrowon copper. Copper cathodes with lead contents of less than 2 ppm were consistently produced. These results were obtained with laboratory-scale equipment and quantitative extrapolation to industrial-scale operations may not be valid. However, the qualitative effects of the various processing conditions should be applicable to industrial electrowinning.     

Electroextraction of lead from a lead trilonate solution

Laboratory studies of the cathode process of the electroextraction of zinc from the trilonate electrolyte obtained after the purification of solutions after leaching lead cakes of zinc production are performed. The potential scan rate is determined by recording potentiodynamic curves; the optimal electrolyte acidity, the composition, and the temperature are established. Values of activation energy confirming the concentration nature of process polarization are found.     

Electrodeposition of magnesium-yttrium alloys by molten salt electrolysis

Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ and Y3+was deposited more prior than other ions during cyclic voltammetry and potential step measurement at 1050 °C.Voltammograms showed Mg2+ could be deposited at-0.5 V,and Y3+ could be deposited at-0.7 V on tungsten electrode compared with platinum electrode.The sedimentation of Mg2+ was more positive about 230 mV than that of other ions in electrolyte.The electrolytic codeposition of yttrium and magnesium was 0.58 V on condition that the weight ratio of Y2O3/MgO was 4:1.Chronopotentiogram indicated that the process of electrodeposition of magnesium-yttrium alloys on tungsten electrode was controlled by diffusion of ions from electrolyte to electrode interface.It was feasible to prepare Magnesium-Yttrium alloys by controlling content of ions in molten salt electrolyte.     

铟电解液净化方法研究

铟电解液的纯度是铟电解提纯效果的主要影响因素之一。为了有效提高铟电解精炼的纯度,对铟电解液的净化方法进行研究,提出静态净化与动态净化的概念,并将静态净化和动态净化相联合对铟电解液进行净化处理。静态净化采用硫酸钡共沉淀方法,动态净化采用海绵铟柱置换方法。研究表明:静态净化的条件为:在搅拌状态下,以BaCl2为沉淀剂,逐滴滴入经硫酸酸化过的铟电解液中。BaCl2用量控制在每升硫酸铟溶液中加入15～30 g氯化钡,反应温度控制在30～50℃之间。动态净化中所用的海绵铟纯度需高于配制电解液所用铟的纯度1～2个数量级,每升电解液需用20～200 g海绵铟。该方法突破单纯静态净化的思路,将电解液的净化过程由电解前延伸至电解过程中,不仅保证了最初配制电解液的纯度,也可以使铟电解液在电解过程中随时得到净化。静态与动态联合的净化方法,同时保证了电解前及电解过程中的电解液纯度,一次电解完毕后可直接重复利用该电解液,不用再进行其他净化,可以大大减少铟电解工艺的工作量。     

电解金属锰生产过程除镁的研究

对电解法炼锰生产过程中的硫酸锰电解液除镁进行研究。先将部分硫酸锰电解液除去重金属杂质,然后对原始电解液和除重金属后的电解液分别使用重结晶法和氟化沉淀法进行除镁对比试验。结果表明,先用硫化沉淀法除重金属,再用氟化沉淀法除镁,除镁效果最佳,除镁率达到92.74%。     

降低高纯铅中的Cu、Bi、Sn等杂质含量

本文叙述了用电解精炼法在制备高纯铅过程中，降低铜、铋、锡杂质含量的各种措施和试验结果，比较详细地介绍了用硫化法降低电解液中的铜、铋、锡杂质的新工艺。