Abstract Activated carbon has been found to significantly enhance the dissolution of gold in a thiosulfate‑oxygen‑copper system. Leaching tests using gold powder showed that the gold dissolution in a thiosulfate‑oxygen‑copper system in the absence of activated carbon was very slow, with only 2% gold dissolved over 24 h. In contrast, in the presence of activated carbon as an additive the gold leach recovery was dramatically improved to over 95% in the same period. Leaching and electrochemical studies using a gold rotating disc electrode have identified two impacts of activated carbon on the dissolution of gold: 1) enhancing the oxygen reduction half reaction via galvanic interaction and; 2) enhancing the gold oxidation half reaction via removal of the surface passivation. A combination of the two effects can potentially increase the gold leach rate to the same order of magnitude as a typical cyanidation rate (10−5 mol m−2 s−1). It has also been found that the presence of copper and the use of an elevated temperature are beneficial for the gold leaching; whilst the use of oxygen instead of air and change in pH between pH 7 and pH 10 have little impact.

中文翻译：

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活性炭存在下硫代硫酸盐-氧-铜体系中金浸出的基础研究

摘要 已发现活性炭可显着提高金在硫代硫酸盐-氧-铜体系中的溶解度。使用金粉的浸出试验表明，在没有活性炭的情况下，硫代硫酸盐-氧-铜系统中的金溶解非常缓慢，24 小时内仅溶解了 2% 的金。相比之下，在活性炭作为添加剂的情况下，同期金浸出率显着提高至 95% 以上。使用金旋转圆盘电极的浸出和电化学研究已经确定了活性炭对金溶解的两个影响：1) 通过电流相互作用增强氧还原半反应；2）通过去除表面钝化增强金氧化半反应。这两种效应的结合可能会将金浸出率提高到与典型氰化率（10-5 mol m-2 s-1）相同的数量级。还发现铜的存在和使用升高的温度有利于金浸出；而使用氧气代替空气以及 pH 在 pH 7 和 pH 10 之间的变化几乎没有影响。