铜-氨-硫代硫酸盐体系金溶出影响因素的电化学研究

铜-氨-硫代硫酸盐浸金体系中，金的溶出本质上是电化学过程。采用交流阻抗和Tafel曲线分析硫代硫酸盐、铜离子、氨浓度对金的溶出影响。结果表明:在金的溶出过程中，硫代硫酸盐和铜离子可能会导致钝化，尤其使铜离子浓度增大会导致钝化加剧，这种钝化会交替出现；氨水不会导致钝化；对金溶出速率的影响，硫代硫酸盐最大，铜离子最为复杂，氨影响相对最小。     

Applications of mixed potential model in leaching of gold

1　ＩＮＴＲＯＤＵＣＴＩＯＮＭｉｘｅｄ ｐｏｔｅｎｔｉａｌｍｏｄｅｌ (ＭＰＭ )ｈａｓｒｅｃｅｉｖｅｄｇｒｅａｔｉｎｔｅｒｅｓｔｉｎｓｔｕｄｙｉｎｇｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｃｏｒｒｏ ｓｉｏｎ[1,2 ] .ＭｉｌｔｏｎａｌｓｏｉｎｔｒｏｄｕｃｅｄＭＰＭｔｏｄｉｓｃｕｓｓｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｄｉｓｓｏｌｕｔｉｏｎｏｆｓｕｃｈｍｉｎｅｒａｌｓａｓｕｒａｎｉ ｕｍｄｉｏｘｉｄｅａｎｄｃｈａｌｃｏｐｙｒｉｔｅ[3] .Ｓｉｎｃｅｇｏｌｄｄｉｓｓｏｌｕｔｉｏｎｉｎｌｉｇａｎｄｓｏｌｕｔｉｏｎｓｉｓａｌｓｏ…     

Sustainable copper extraction from mixed chalcopyrite–chalcocite using biomass

This paper elaborated on the sustainability of the copper extraction process. In fact, an alternative copper extraction route from mixed sulphide ores, chalcopyrite and chalcocite using mesophilic biomass consortium at 33.3 °C and ferric leaching process were attempted. Bioleaching experiments were settled with a fraction size of −75+53 µm. Bacteria were used as the catalyst. A copper yield of 65.50% was obtained. On the other hand, in ferric leaching process, with a fraction size of −53+38 µm, when the temperature was increased to 70 °C, the copper leaching rate increased to 78.52%. Thus, comparatively, the mesophilic bioleaching process showed a more obvious advantage in copper extraction than leaching process with a high temperature. However, it has been resolved from the characterization performed using SEM−EDS, FTIR and XRD observations coupled with different thermodynamic approaches that, the indirect mechanism is the main leaching mechanism, with three transitory mechanisms (polysulphide, thiosulphate and elemental sulphur mechanisms) for the mixed chalcopyrite−chalcocite ore. Meanwhile, the speciation turns into Cu₂S−CuS−Cu₅FeS₄−Cu₂S before turning into CuSO₄. While ferrous oxidation and the formation of ferric sulphate occur, and there is a formation of strong acid as bacteria digest sulphide minerals into copper sulphate at low temperature, which is why this copper production scenario requires a redox potential more than 550 mV at room temperature for high copper leaching rate.     

The role of ligands and oxidants in thiosulfate leaching of gold

The widely used cyanidation technology is not applicable to some gold ores due to economic or technical reasons when the cyanidation gives very low gold extractions. Despite the fact that the gold mining industry accounts for only 13% of total cyanide consumption there is growing public concern over the use of toxic cyanide for gold extraction. Many researchers have identified that thiosulfate leaching is the most likely alternative to cyanidation due to nontoxicity, low cost and other benefits. This article describes the current information on stoichiometric relationships, equilibria, reaction rates and mechanisms related to anodic or chemical oxidation of gold in thiosulfate, ammoniacal thiosulfate and ammoniacal copper(II) thiosulfate solutions in the presence or absence of oxygen.     

Silver sulfide leaching with a copper-thiosulfate solution in the absence of ammonia

Leaching from silver sulfide using a copper-thiosulfate solution in the absence of ammonia was investigated.It is found that silver sulfide could be effectively dissolved in the copper-thiosulfate system without ammonia.The effects of thiosulfate concentration,copper-to-thiosulfate ratio,agitation vigorousness,pH values,and dissolved gases on the leaching of silver sulfide with the copper-thiosulfate solution were studied.A maximum extraction of 95.1% was achieved with the 0.12 mol/L thiosulfate and the 0.048 mol/L copper sulfate.It is shown that copper-to-thiosulfate ratio is an important factor in silver sulfide dissolution and oxygen is not needed to leach silver sulfide,which leads to the instability of the leaching system at high copper-to-thiosulfate ratio.On the other hand,the silver extraction is not affected by the pulp pH values.     

The cuprex metal extraction process: Recovering copper from sulfide ores

The Cuprex? metal extraction process produces cathode-grade copper using a hydrometallurgical process based on chloride leaching of sulfide ore concentrates. The process incorporates several novel steps to overcome the major problems associated with earlier chloride-based processes, including mild leaching conditions using ferric chloride as leachant and solvent extraction of copper usinga novel reagent. This produces a highly concentrated cupric chloride electrolyte from which cathode-grade copper is electrowon in the Metclor cell. The technical viability and robustness of the core technology have been proven in a series of large-scale pilot trials. More recent work has concentrated on supplementary processes to convert the copper powder product to an article of commerce and to recover valuable by-products. A fully integrated scheme is now being developed with updated cost estimates.     

A new extraction process of carbonaceous refractory gold concentrate

A new hydrometallurgical process for a carbonaceous refractory gold concentrate at ambient temperature and pressure was presented, including grinding-leaching, intensified alkaline leaching（IAL）, thiosulfate leaching and cementation by zinc powder. The experimental results show that the grinding-leaching and intensified alkaline leaching process result in the selective oxidation of arsenopyrite and pyrite. The oxidation ratio of As is 96.6%, and 46.7 % for S. The total consumption of NaOH in alkaline leaching is only 28 % of that theoretically calculated under the conditions of full oxidization for the same amount of arsenopyrite and pyrite transforming into arsenates and sulfates, and 83.6% of gold is synchro-dissoluted by thiosulfate self-generated during pretreatment. Since the carbonaceous matter in concentrate possesses a strong capability of preg robbing, the cyanidation process is not suitable for the extraction of gold after pretreatment. However, the gold leaching rate by thiosulfate leaching for 24 h is increased to 91.7% from 0 - 3.2% by ultra-fine grinding without the pretreatment. The recovery of gold by zinc cementation gets to 99.6%. Due to the thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal one.     

难处理金矿非氰提金方法研究现状

简要叙述了难处理金矿资源现状,分别介绍了硫脲法、硫代硫酸盐法、卤素法、石硫合剂法等非氰提金方法的浸出机理及国内外最新研究状况,综合比较各种方法的优缺点,最后指出其今后发展方向。     

Comparison on the leaching kinetics of chalcocite and pyrite with or without bacteria

The acid leaching, ferric leaching, and bioleaching of chalcocite and pyrite minerals were conducted in two sets of 3L stirred reactors. The dissolution rates of copper and iron were correlated with leaching conditions. In the acid leaching process, the dissolution rate of chalcocite was around 40wt.% while that of pyrite was less than 4%. In the ferric leaching process with high ferric concentration, only 10 wt.% of iron in pyrite was leached out at the same retention time though the copper recovery over 60 wt.% in chalcocite. For the bioleaching process, the chalcocite leaching rate was highly increased, nearly 90 wt.% of copper was leached out, and the iron dissolution of pyrite exceeded 70 wt.%. For the two minerals, the bioleaching shows the highest leaching rate compared with the acid leaching or ferric leaching. In uncontrolled bioleaching process, pyrite could be dissolved effectively. The experimental data were fitted to the shrinking core and particle model. The results show that in all the leaching tests, the chalcocite leaching was mainly controlled by diffusion, while for the pyrite leaching, chemical reaction is the main rate-determining step.     

Effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores

The effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores was carried out by phase analysis means of XRD, optical microscopy and SEM−EDS. The results indicated that at ambient temperature, the easily leached copper oxide minerals were completely dissolved, while the bonded copper minerals were insoluble. At lukewarm temperature of 40 °C, it was mainly the dissolution of copper in isomorphism state. With increasing temperature to 60 °C, the copper leaching rate in the adsorbed state was significantly accelerated. In addition, when the temperature increased to 80 °C, the isomorphic copper was completely leached, leaving 11.2% adsorbed copper un-leached. However, the copper in feldspar−quartz−copper−iron colloid state was not dissolved throughout the leaching process. Overall, the leaching rates of copper in different copper minerals decreased in the order: malachite, pseudo-malachite > chrysocolla > copper-bearing chlorite > copper-bearing muscovite > copper-bearing biotite > copper-bearing limonite > feldspar−quartz−copper−iron colloid.     

Gold leaching with elemental sulfur in alkaline solutions under oxygen pressure

1　ＩＮＴＲＯＤＵＣＴＩＯＮＣｙａｎｉｄａｔｉｏｎｐｒｏｃｅｓｓ ,ｃｈａｒａｃｔｅｒｉｚｅｄｂｙｅｆｆｅｃｔｉｖｅｎｅｓｓａｎｄｌｏｗｏｐｅｒａｔｉｎｇｃｏｓｔ,ａｓａｃｏｎｖｅｎｔｉｏｎａｌｔｅｃｈｎｏｌｏｇｙｆｏｒｇｏｌｄｅｘｔｒａｃｔｉｏｎｆｒｏｍｏｒｅｓ ,ｈａｓｂｅｅｎｕｓｅｄｉｎｉｎｄｕｓｔｒｙｆｏｒｏｖｅｒ 10 0ｙｅａｒｓ .Ｈｏｗｅｖｅｒｔｈｅｃｙａｎｉｄｅｉｓａｈｉｇｈｌｙｔｏｘｉｃｃｈｅｍｉｃａｌ,ａｎｄｃｏｍｍｅｒｃｉａｌｃｙａｎｉｄａｔｉｏｎｐｒｏｃｅｓｓｉｓｌｉｍｉｔｅｄｉｎｔ…     

Recovery of valuable metals from zinc leaching residue by sulfate roasting and water leaching

Zinc leaching residue (ZLR), produced from traditional zinc hydrometallurgy process, is not only a hazardous waste but also a potential valuable solid. The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR. The ZLR was initially roasted with ferric sulfate at 640 °C for 1 h with ferric sulfate/zinc ferrite mole ratio of 1.2. In this process, the valuable metals were efficiently transformed into water soluble sulfate, while iron remains as ferric oxide. Thereafter, water leaching was conducted to extract the valuable metals sulfate for recovery. The recovery rates of zinc, manganese, copper, cadmium and iron were 92.4%, 93.3%, 99.3%, 91.4% and 1.1%, respectively. A leaching toxicity test for ZLR was performed after water leaching. The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.     

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution. The concentration of ammonia and ammonium chloride, the ore particle size, the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments. The results show that temperature, concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores. But, leaching rate decreases with increasing particle size and solid-to-liquid ratio. The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol. An equation was also proposed to describe the leaching kinetics.     

电镀软金用硫基无氰金配合物电解质研究进展

电镀金工艺中金氰化物([Au(CN)_2]~-)溶液在过程中会释放出剧毒的游离氰化物离子,严重危害到生产人员和自然环境的健康;此外,它们还会对光刻胶造成一定的破坏。近年来无氰电解质得到了发展。基于对50余篇文献的分析,本文比较了亚硫酸金([Au(SO_3)_2]_3~-)、硫代硫酸金([Au(S_2O_3)_2]_3~-)和二者混合电解液,以及其他硫基体系的组成、操作条件、电沉积机理和优缺点,并展望了基于无氰配体电解液的软金电镀技术的研究趋势和发展方向。     

ELECTROCHEMICAL STUDIES ON THE MECHANISM OF GOLD DISSOLUTION IN THIOSULFATE SOLUTIONS

ＥＬＥＣＴＲＯＣＨＥＭＩＣＡＬＳＴＵＤＩＥＳＯＮＴＨＥＭＥＣＨＡＮＩＳＭＯＦＧＯＬＤＤＩＳＳＯＬＵＴＩＯＮＩＮＴＨＩＯＳＵＬＦＡＴＥＳＯＬＵＴＩＯＮＳＺｈｕ，Ｇｕｏｃａｉ；Ｆａｎｇ，Ｚｈａｏｈｅｎｇ；Ｃｈｅｎ，Ｊｉａｙｏｎｇ（ＩｎＳｔｄｕｔｅｏｆＣｈ...     

铂钯精矿中氯化银的浸出预处理研究

铜阳极泥分铜液所得铂钯精矿中的银主要以氯化银(AgCl)形态存在，可用氨水或亚硫酸钠作为浸出剂去除银。绘制了Ag⁺与NH3、SO2- 3配体组分图，结合电位-pH图分析表明，氨浸的pH值范围为7.7~13.5，亚硫酸钠浸出宜在中性或碱性条件下进行。优化条件实验结果表明，银的氨浸浸出率为95.3%，碲浸出率为14.9%，有微量铂、钯浸出；以亚硫酸钠为浸出剂，银的浸出率为97.3%，碲浸出率为11.5%，金、铂和钯均不被浸出。亚硫酸钠更适于作为铂钯精矿预处理除银的浸出剂。     

从脱铜阳极泥中浸出贵金属的预处理工艺研究

采用硫代硫酸盐浸出脱铜阳极泥中的贵金属金、银和钯,研究氧化焙烧、碱预浸出和酸预浸出的预处理工艺对提高浸出率的影响。结果表明,3种预处理方式可在不同程度上降低硫、砷、锑、铅等元素对浸出效率的影响,采用氧化焙烧-酸预浸出-硫代硫酸盐浸出的方案,金、银和钯的浸出率分别达到了93.45%、96.32%和76.04%。     

从氧化铜矿氨浸渣中浮选回收银

某高碱性含银氧化铜矿氨浸渣含银145.55 g/t。对氨浸渣进行了浮选回收银的试验,结果表明,采用三粗一扫两精的流程,经过闭路流程试验,可获得达到计价标准的银精矿,其银品位为1999.58 g/t、回收率80.78%。     

氨-硫酸铵体系过硫酸盐氧化含钙镁碳酸盐低品位铜矿的浸出动力学(英文)

研究在氨?硫酸铵体系中用过硫酸盐氧化低品位铜矿浸出动力学,确定搅拌速度、浸出温度、矿物粒度及氨、硫酸铵和过硫酸钠的浓度对浸出的影响。结果表明,搅拌速度在300r/min以上时对浸出速度无影响,浸出速度随反应温度及氨、硫酸铵和过硫酸钠浓度的增大而增加。对浸出渣的EDS和物相定量分析表明斑铜矿被过硫酸盐氧化而溶解于氨?硫酸铵溶液。用产物层的界面传质和扩散控制的收缩核模型分析铜矿的溶解动力学,其表观活化能为22.91kJ/mol,同时获得了描述浸出过程的半经验动力学方程,其对氨、硫酸铵和过硫酸钠的浓度的表观反应级数分别为0.5、1.2和0.5。     

低品位氧化铜矿氨-硫酸铵体系过硫酸铵氧化浸出

以过硫酸铵为氧化剂,研究低品位氧化铜矿在氨-硫酸铵体系氧化浸出工艺。讨论氨/铵离子摩尔比、总氨浓度,氨、硫酸铵和过硫酸铵的浓度,反应温度,液固比,反应时间和搅拌速度等操作条件对铜浸出的影响。结果表明:在92.8%的矿样粒径小于0.045 mm,氨、硫酸铵和过硫酸铵浓度分别为2.4、1.8和0.100 mol/L,浸出时间为90 min,温度为30℃,液固比(mL/g)为5:1,搅拌速度为500 r/min时的优化条件下,低品位铜矿的铜浸出率达87.7%。