The direct electrorefining of copper matte

Direct electrorefining of copper matte would be a desirable alternative to copper converting and its associated troublesome sulfur dioxide emissions. After more than 100 years of study, however, no commercial process has been developed, even though an analogous process for the direct electrorefining of nickel matte anodes has been operating successfully for several decades. The unique difficulties associated with copper matte electrorefining are related to the properties of the matte’s decomposition products.     

Using polyethylene glycols as alternative inhibitors in copper electrorefining

Polyethylene glycols (PEGs) with well-defined molecular weight ranges are interesting alternative additives for copper electrorefining. In comparison to glue, PEGs offer high thermal stability and slow chemical decomposition at higher temperatures, with high cathodic polarization. Thosefactors are advantages for an optimized process control in copper electrorefining. Investigations into cathodic polarization as a function of molecular weight and concentration at 500 A/m², and also into the half-life of PEGs, were conducted in typical copper electrolyte.     

Recovering Bi and Sb from electrolyte in copper electrorefining

The separation of antimony and bismuth in copper electrorefining is somewhat difficult and costly. An ion-exchange technique for the removal of the metals from the electrolyte has been practiced recently, although the metals recovered require further processing. Sumitomo Metal Mining has developed a process to recover antimony and bismuth directly from the eluant by an electrowinning process using a mixture of sulfuric acid and sodium chloride as an eluant for the desorption from the resin. The content of bismuth in the antimony metal recovered by this process was less than 0.2%, while the content of antimony in the bismuth metal was less than 0.4%. K. Ando earned his M.Sc. in metallurgical engineering at Kumamoto University in 1986. He is currently a senior scientist at Sumitomo Metal Mining Company. N. Tsuchida earned his Ph.D. in mineral science at Murdoch University, Western Australia, in 1986. He is currently manager of the Niihama nickel refinery at Sumitomo Metal Mining Company.     

含钴铜转炉渣的工艺矿物学

研究了铜转炉渣的化学与矿物学特征,用光学显微镜查明了炉渣各主要渣相为铁橄榄石,磁铁矿和无定形玻璃体,铜主要以冰铜相裹夹于渣相中,铜滴的尺度与渣的冷却历史有关。用X射线衍射谱,扫描电子显微镜,X射线能谱和X射线波谱及化学物相分析,对铜和钴的赋存状态及在各相中的分布进行了表征和量化。结果表明,钴主要以类质同象形式取代铁橄榄石和磁铁矿晶格中部分Fe^2 ,作为氧化物富集其中,二者约占钴总量的95％,渣中钴的提取需要以铁橄榄石和磁铁矿的分解为前提,使钴的氧化的游离出来而酸溶。     

Chlorine inclusion mechanism in high purity copper electrorefining from nitric acid system

A practical approach was introduced to study the inclusion mechanism of chlorine in high purity copper electrorefining from nitric acid system via cyclic voltammetry (CV) combined with electrodeposition experiments. The CV curves display an obvious reduction peak of CuCl intermediate, which can provide an insight into the electrochemical behavior of this inclusion. Experimental results show that the increase of HNO₃ concentration is favorable to reducing the quantity of chlorine inclusion although there is a slight decline in cathodic current efficiency. The optimum conditions for copper electrorefining in nitric acid system are HNO₃ concentration in solution of 1−2 mol/L, moderate temperature of ~35 °C with current density not exceeding 25 mA/cm². Based on the theoretical studies, an optimized copper electrorefining experiment was designed to simulate the industrial electrolysis, by which high purity copper can be obtained with chlorine inclusion less than 10 μg/g and current efficiency higher than 90%.     

High current density copper electrorefining and electrowinning in a series cell Part I—Electroretining

In this portion of a two-part paper, the design and testing of a series cell capable of achieving power consumption as low as 0.18 kwh per Ib at 84 ASF is described.     

Sb(V) removal from copper electrorefining electrolyte: Comparative study by different sorbents

Removal of Sb(V) from copper electrolyte by different sorbents such as activated carbon, bentonite, kaolin, resin, zeolite and white sand was investigated. Adsorption capacity of Sb(V) removal from copper electrolyte was as follows: white sand < anionic resin < zeolite < kaolin < activated carbon < bentonite. Bentonite was characterized using FTIR, XRF, XRD, SEM and BET methods. The results show specific surface area of 95 m²/g and particles size of 175 nm for bentonite. The optimum conditions for the maximum removal of Sb are contact time 10 min, 4 g bentonite and temperature of 40 °C. The adsorption of Sb(V) on bentonite is followed by pseudo-second-order kinetic (R²=0.996 and k=9×10^?5 g/(mg·min)). Thermodynamic results reveal that the adsorption of Sb(V) onto bentonite from copper electrolyte is endothermic and spontaneous process (ΔG^Θ=–4806 kJ/(mol·K). The adsorption data fit both the Freundlich and Langmuir isotherm models. Bentonite has the maximum adsorption capacity of 10000 mg/g for adsorption of Sb(V) in copper electrolyte. The adsorption of Zn, Co, Cu and Bi that present in the copper electrolyte is very low and insignificant.     

Direct electrorefining of nickel matte

International Nickel Company has unveiled a new electrorefining process which recovers high purity sulfur, selenium, and cobalt.     

四甲基氯化铵对AlCl_3-BMIC离子液体体系在铜基体上电解精炼铝的影响

讨论了四甲基氯化铵(TMAC)对AlCl3-BMIC(AlCl3摩尔分数为0.667)离子液体体系在铜基体上低温电解精炼铝过程中的电流效率、槽电压和能耗的影响。结果表明:TMAC的加入能够提高电流效率,降低槽电压和能耗;且在铜基体上能够得到光亮、平整致密、晶粒细化的铝沉积层。当TMAC加入量为0.02mol/L时,能够获得最大电流效率(91%)和最低能耗(0.861kWh/kg-Al);而且阴极极化曲线表明,阴极铝还原峰电位逐渐向正方向移动,TMAC对电解精炼铝过程中的铝电还原有去极化影响。所有实验条件下,铜基体上所得铝沉积层的纯度超过99.9%。     

Preparation of high-purity indium by electrorefining

The application of indium requires high purity indium as material, and the high purity indium has been prepared by electrorefining. The selection and preparation of electrolyte in electrorefining indium were investigated,and the effect of component of electrolytic solution on electrolytic refining was also studied. Compared with electro-lyte of InCl3-HCl, electrolyte of In2(SO4)3-H2 SO4 has higher stability and lower corrosivity, electrolytic solution can be heated at low temperature, and bath is open and simple, which makes operation more convenient. The results show that the voltage can be kept at 0. 3-0.5 V, and the content of indium can exceed 99. 999% when the contentof indium(Ⅲ) ion and sodium chloride are 80-120 g/L. The bench-scale test of electrolysis was carried out, and the product of indium reaches the national standard of 99. 999% high purity indium.     

The mineralogy of bauxite for producing smelter-grade alumina

Aluminum-producing companies rely on low-cost, high-purity, smelter-grade alumina (aluminum oxide), and alumina production utilizes the bulk of bauxites mined world-wide. The mineralogy of the bauxites has a significant impact on the operation of the Bayer process for alumina production. Typically, the Bayer process produces smelter-grade alumina of 99.5% Al₂O₃, starting from bauxite containing 30% to 60% Al₂O₃. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions. Only with a better understanding of the chemistry of the mineral species and a strict control of the operating/processing conditions can the Bayer process produce efficiently, a low cost, high-quality alumina with minimum detrimental environmental impact. For more information, contact M. Authier-Martin, Raw Materials R&D, Arvida Research and Development Centre, Alcan International Limited, Jonquiere, Quebec, Canada G7S 4K8; monique.authier@alcan.com.     

Effects of neodymium oxide on an electrorefining process of uranium

Electrorefining experiments of uranium were carried out in LiCl–KCl eutectic molten salt containing metallic U and Nd₂O₃ compacts as a surrogate material of an electrolytically reduced spent PWR fuel at 500 °C to observe the dissolution behavior of Nd₂O₃. The Nd₂O₃ compacts were significantly attacked in the electrorefining condition regardless of the current density. It was found that the UCl₃, which is an essential chemical for a uranium electrorefining, played a decisive role in the resultant chemical reaction with Nd₂O₃. This dissolution phenomenon of NdCl₃ formed by the chemical reaction between Nd₂O₃ and UCl₃ was confirmed by an in situ UV–vis absorption spectrometry equipped with a homemade high-temperature apparatus and XRD analysis. The effects of uranium oxide particle as a by-product in the electrorefining process were also discussed by using computational fluid dynamics analysis.     

The process mineralogy of gold: The classification of ore types

The principal gold minerals that affect the processing of gold ores are native gold, electrum, Au-Ag tellurides, aurostibite, maldonite, and auricupride. In addition, submicroscopic (solid solution) gold, principally in arsenopyrite and pyrite, is also important. The main causes of refractory gold ores are submicroscopic gold, the Au-Ag tellurides, and very fine-grained gold (<10 μm) locked in sulfides. Other types of problem gold ores include copper-gold ores and preg-robbing carbonaceous ores. J.P. Vaughan is associate professor and head of the Mining Geology Program at the Western Australian School of Mines, Curtin University of Technology, and carries out research in process mineralogy for the A.J. Parker Cooperative Research Centre for Hydrometallurgy, Perth, Western Australia.     

熔盐电解精炼提纯金属硅(英文)

对熔盐电解质中硅的沉积过程进行电化学研究。在 973~223K,在硅氯化物熔盐中采用电解精炼提纯金属硅。结果表明,液态硅铜合金阳极有利于 CaCl2-NaCl-CaO-Si 熔盐体系的电解精炼。ICP-AES 分析结果显示,通过电解精炼可有效去除原料中大量的钛、铝、铁等金属杂质,硅中的硼和磷含量分别由 36×106和 25×106降低至 4.6×10 6和 2.8×10 6,电解能耗约为 9.3 kW·h/kg。     

Applied mineralogy of refinery slags

The techniques of process mineralogy can be effectively applied to the study of slags. By these techniques, the minerals or phases, phase chemistry, phase abundance, associations, crystalline habit, grain size, microtextures, and causes for certain metallurgical problems, such as metal losses to the slags, can be readily deduced. This case history is an example of the application of process mineralogy to the study of metal losses in a slag from a secondary copper refinery.     

河南铝土矿工艺矿物学研究

详细研究了河南铝土矿物的物质组成、嵌布特性、粒度特性、铝硅的赋存状态以及这些工艺性质对造冶工艺的影响。     

铟电解精炼中电解液酸度对锡含量的影响

研究了铟的电解精炼中电解液的选择与配制和酸度对杂质锡含量的影响,并初步探讨了电解液中锡离子的行为。研究表明：采用In2(SO4)3—H2SO4体系具有组成简单、操作方便、阳极无毒性气体析出的优点。锡在阴极主要以Sn^2 的形式析出,电解液的酸度控制在pH值2—3之间,可将锡含量控制在最低水平。电解过程中,阴极pH值将增大,阳极pH值将变小,可通过加入H2SO4和固体的NaOH颗粒来控制电解液酸度。