Recovery of copper cyanide from waste cyanide solution by LIX 7950

The use of the guanidine extractant, LIX 7950, to extract copper cyanide from waste cyanide solution has been investigated. Copper extraction is favorable at low pH while a high cyanide to copper molar ratio tends to suppress copper loading. The extractant also strongly extracted zinc and nickel from cyanide solution, but the extraction of iron was poor. The presence of thiocyanate ion significantly depressed copper extraction, but thiosulfate ion produced negligible impact on copper extraction. The preferential extraction of metal cyanide species to free cyanide has been noticed. The potential application of the recovery technique as a pre-concentration step for the treatment of cyanide effluent has been suggested, by which copper can be extracted and concentrated into a small volume of solution and the barren cyanide solution recycled to the cyanidation process.     

Copper and nickel recovery from acidic polymetallic aqueous solutions

Acidic polymetallic wastewaters are generated during the pyrometallurgical treatment of chalcopyrite for the production of primary copper. The most important wastewater streams originate from the copper refining and the electrolyte regeneration stages, as well as the sulphuric acid and the precious metals plants. These wastewaters are characterized by medium to high concentration of residual sulphuric acid and heavy metals such Cu, Ni, Pb, Zn, Fe, As, Sb, Bi, etc. Taking into account that the outflows of these industrial streams are usually high, a large amount of valuable metals such as copper and nickel are potentially lost. Thus, it is of great importance to treat properly the wastewaters so that the contained valuable metals to be recovered. This paper is dealing with the treatment of synthetic solutions simulating industrial wastewaters from the copper pyrometallurgical plant in Bor, Serbia. The basic concept includes copper electrorecovery followed by nickel precipitation through neutralization. The feasibility of this treatment was proved theoretically with the thermodynamic analysis of electrochemical and precipitation reactions in this system, as well as experimentally under various conditions. The main conclusion is that copper can be recovered electrolytically followed by bismuth and the two metalloids arsenic and antimony that exhibits almost the same electronegativity with copper. The other high electropositive metals Ni, Pb, Zn, Fe remain, as it was expected, in the solution from which nickel can be recovered with neutralization, contaminated with Cu, Fe, Zn and traces of bismuth, arsenic and antimony. The proposed treatment technology has innovative character because it can mitigate environmental impacts and eliminate solid waste generation while at the same time can recover valuable metals.     

Solvent extraction of gold(I) from alkaline cyanide solutions by the cetylpyridinium bromide/tributylphosphate system

This paper explores the solvent extraction of KAu(CN)₂ from alkaline cyanide solutions using quaternary ammonium cetylpyridinium bromide (CPB) as an extractant with the addition of tributylphosphate (TBP) as a modifier. It also investigates the influence of several variables on gold extraction, including the molar ratio (β) of CPB to Au(I), the volume percentage of TBP (φ_TBP), NaCl concentration, phase ratio (AQ/ORG), and gold concentration in the aqueous phase. The results indicate that nearly all of the Au(I) (>98%) was transferred from the aqueous phase into the organic phase when β = 1 and φ_TBP = 30 vol%. We also carried out experiments for treating 20 L synthetic aurocyanide solution containing 10 mg/L Au(I) with column-shaped extraction equipment. The results demonstrated the recovery of more than 94.5% of Au(I) after two successive stages of extraction, and the Au(I) concentration in the raffinate was less than 0.5 mg/L. KSCN solution was used to strip the gold-loaded organic phase, and about 90% of Au(I) could be reverse extracted into the aqueous phase when the KSCN concentration reached 3.0 mol/L. The results obtained in this paper establish that the CPB/TBP extraction system has potential for practical application in the extraction and separation of gold from alkaline aurocyanide solutions.     

Extraction of hydrogen cyanide from waste solutions of cyaniding circuit for sulfide flotation concentrates

The process for extraction of hydrogen cyanide to decontaminate solutions produced at cyaniding of sulfide flotation concentrates is developed. The centrifugal-bubbling apparatus is employed as a reactor. The regularities of HCN formation in an acid medium are established in investigation into kinetics of SCN⁻ thiocyanate oxidation by hydrogen peroxide H₂O₂ in presence of Fe²⁺, Fe³⁺ and pH ≤ 3.5. In the process proposed the evolved HCN is adsorbed by NaOH solution and returned to the circuit of leaching of gold and silver as NaCN, and the waste cyaniding solution is discharged into a waste dump, where it is mixed with industrial water to be utilized to transport flotation tailings. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 98–105, January–February, 2009.     

铜冶炼渣浮选回收铜的研究现状

我国铜冶炼企业每年产生了大量的铜冶炼渣,其中含有大量的有价元素,如金、银、铜、钴、镍等,具有巨大的经济价值。如何经济环保地综合回收这部分有价元素不仅能为企业带来巨大的经济价值,更重要的是能解决铜渣大量堆存的问题。本文综述了目前铜冶炼渣浮选回收铜的研究进展,并在此基础上提出一些想法,为今后的铜渣综合回收提供了参考。     

Copper Ion Recovery from Mine Water by Ion Flotation

Solutions containing copper ions are produced at copper mines due to its dissolution from ores and dumps. It is important to recover these ions to prevent this toxic element from entering the environment and because it could be economical. We investigated the use of ion flotation for extracting Cu ions from diluted mine water from the Veshnaveh Mine in Qom, Iran. Experiments were conducted using floatation cells at pH 6, 9, and 12 with diluted solutions containing 10 mg L^?1 of Cu. Sodium dodecyl sulfate and hexadecyl trimethyl ammonium bromide (HTAB) were used as collectors and methyl isobutyl carbinol (MIBC) and ethanol were used as frothers. The best result was achieved by maximizing Cu ion recovery and minimizing water recovery at pH 12, using 100 mg L^?1 of HTAB and 0.1 % (v/v) of MIBC. Copper and water recovery were 79 and 24 %, respectively.     

Gold cementation from thiocyanate solutions by iron powder

Gold cementation with iron powder from thiocyanate solutions was conducted without de-aeration. The effects of various parameters such as pH, thiocyanate concentration, gold concentration, iron/gold mass ratio, temperature, stirring speed and presence of iron(III) in the solution were examined. These parameters were varied according to the ranges typically found in the literature. The effect of gas atmosphere on cementation of gold was also examined by flowing nitrogen gas through the solution during the runs and the recovery of gold was enhanced. The presence of iron(III) results in the low efficiency of gold precipitation as well as the low grade of the cements. It was established that the rate of the reaction was first-order with respect to the gold concentration. The activation energy was found to be 9.3 kJ/mol and the cementation process was considered to be diffusion-controlled. A general mechanism for gold cementation is proposed.     

高温贫化-浮选法从炼铜水淬渣中回收铜

考察了贫化温度、硫化剂、还原剂、缓冷速率等因素对炼铜水淬渣中铜回收指标的影响。试验表明,当贫化温度保持在1350℃、硫化剂黄铁矿配比为5%、还原剂煤粉与硫化剂之比为1∶4、缓冷速率为5K/m in时,可获得粗选铜回收率78%左右、粗选精矿铜品位5.8%左右的技术指标。     

云南某低铜贫铁矿石选铜试验

云南某低铜贫铁矿石铜含量为0.35%、铁含量为19.22%,91.43%的铜为硫化铜。对该矿石中铜的选矿工艺进行了研究。结果表明,矿石在磨矿细度为-200目占80%的情况下,以TX-31为浮铜捕收剂,经1粗2扫3精、中矿顺序返回流程处理,获得了铜品位和铜回收率分别为22.48%和91.20%的铜精矿,较好地实现了铜的回收,选铜铁损失率仅为2.18%,为后续选铁创造了条件。     

云南大红山铜矿化学浸出研究

以云南大红山铜矿的铜精矿为研究对象,分别考查其在稀硫酸、硫酸高铁、硫酸亚铁三种介质中的溶解情况。通过试验研究发现,在pH1.0~2.0、常温常压条件下,该铜精矿基本不溶于稀硫酸溶液和硫酸高铁溶液,而在硫酸亚铁溶液中该铜精矿溶解速率明显加快,但浸出后期有明显的钝化现象。浸渣XRD和SEM分析表明,硫酸亚铁溶液浸出后浸出渣有单体硫物相存在,而且矿物表面有明显的"腐蚀坑",能谱分析也证实矿物表面有硫元素过量的情况。另外,硫酸亚铁溶液浸出过程中体系酸耗明显增加,这一方面是由于Fe2+离子氧化造成的,另一方面矿石的大量溶解也增加了酸耗量。     

Strontium removal from aqueous media by natural and modified sorbents

The article presents the analysis of application of a natural and then modified mineral sorbent to strontium removal from natural and waste waters. The authors have shown the high-efficient sorption capacity of naturally occurring and thermally treated brucite relative to strontium. Besides, they have revealed the relationships of the mineral sorption and pH of a water medium, as well as the interaction of strontium and the sorbent surface. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 104–109, May–June, 2009.     

炼铜炉渣浮选铜研究与实践进展

简要介绍了影响炼铜炉渣浮选铜的各种因素以及炼铜炉渣浮选铜在我国的发展与应用情况。     

固定化细胞移动床浸出高硫高铁低铜难选铜矿中铜的研究

利用自制载体将T.f和T.t菌固定起来,并应用于高硫高铁低铜矿的浸出研究中,研究固定化浸矿系统的效果、特点.实验结果表明:在相同的浸提时间(18d)内,T.f和T.t菌混合固定后浸提系统,比非固定化浸系统要高出16.7％;而且固定混合菌群的浸矿效果要优于固定单一菌群的浸矿效果,T.f和T.t菌混合固定的比例为1∶2.     

地下水中氰化物污染状况分析

以异烟酸一吡唑啉酮分光光度法对赤峰市某村30个监测点进行两个月的氰化物监测,采用标准指数法,评价分析该村地下水中氰化物污染现状.通过对氰化物污染空间及时间变化特征的分析得出,离采矿区较近的区域氰化物污染严重;在对氰化物污染未进行处理的情况下,未污染区地下水发生氰化物污染的可能性随着时间增加有增长的可能.为该村地下水污染推荐一些治理措施.     

On-site gold refining of cyanide liquors by solvent extraction

Gold producers are currently being forced to cut costs, to increase plant throughput or to selectively mine out higher-grade areas. Another approach is to produce a value-added product, such as 99.99% gold, currently being produced at some minesites via a chloride re-leach route. There may be an opportunity for the refining of gold directly from cyanide liquors such as eluates and intensive leachates of gravity concentrates. While previous work with solvent extractants has focused on the recovery of gold from leach liquors as a replacement for carbon-in-pulp processing, the present work presents an alternative idea, the notion of on-site refining of gold with no re-leaching step.The current work indicates that it is possible to produce gold of 99.99% purity or higher by direct SX from a cyanide eluate type solution containing high copper tenors (about 200 mg/l Au, 140 mg/l Cu and 2 mg/l Ag). Excellent selectivity can be achieved in the extraction stage for gold over copper and silver. The small amount of co-extracted silver and copper can easily be scrubbed from the gold-loaded organic phase, which is subsequently easily stripped. The gold may then be recovered by electrowinning or reduction.Other work on a mixed-metal intensive cyanide leachate type solution (700 ppm Au, 400 ppm Ag, 200 ppm Cu, 150 ppm Ni, Fe, and Zn) has shown that the process is very selective against base metals such as Ni, Co, Fe and Zn, and that loadings as high as 5000 mg/l gold can be obtained on the organic.This process may well be suited to gold plants at remote sites, or where high copper or silver levels are present. There are several possible advantages over both electrowinning/smelting or chloride re-leach/SX routes, including costs, occupational health and safety (OH&S) and recovery of by-products.     

Fine particle removal from mud

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Mass transfer correlation of removal of nickel by cementation onto rotating zinc disc in industrial zinc sulfate solutions

A rotating zinc disc was used to study the cementation of nickel from an industrial acidic solution of zinc sulfate. The reduction of nickel was evaluated for a wide concentration range of initial nickel concentration, electrode rotation speed and temperature. The rate of cementation giving the product ka_e of the local mass transfer coefficient k and the effective surface area a_e was analyzed and expressed in terms of the rate of mass transfer versus the apparent mass transfer coefficient and correlated by a controlling numbers relationship.An estimation, by two methods, of the surface roughness variation caused by the nickel deposit was presented.     

硅胶-聚合胺树脂在模拟硫酸镍电解液中深度净化除铜

用离子交换柱在Ni2+70g/L,Cu2+0.5～2.0g/L,pH=1～4,温度20℃～60℃的模拟硫酸镍电解液中研究硅胶-聚合胺树脂从硫酸镍电解液中深度净化除铜的过程.用H2SO4浓度分别为1.0,1.5,2.0mol/L的解析液考察树脂的解析性能.结果表明,随料液pH增大以及温度升高,树脂对铜的交换容量增大,料液Cu2+浓度对交换容量影响不大.最佳吸附条件为料液pH=4,吸附接触时间30min,温度60℃.最佳解析条件为H2SO42mol/L,解析接触时间40min.最佳工艺条件下,树脂的铜穿漏及饱和交换容量分别为0.378和0.496 mmol/mL-湿树脂,铜解析液峰值浓度可达38g/L以上.     

从冶炼铜渣回收铜铁的试验研究

介绍了铜渣中铜和铁的赋存状态,分析了影响铜渣中铜、铁回收的主要因素。对某铜业公司冶炼炉渣采用浮选与磁选综合回收铜、铁的工艺流程进行了试验,并取得了较好的指标。在磨矿细度为-0.037 mm占95.27%,通过一粗二扫再精选闭路流程,获得了铜品位46.36%、回收率83.63%的铜精矿;通过二段磨矿加入分散剂,获得了铁品位51.81%、回收率为30.88%的铁精矿。