Abstract For the last two decades, a considerable amount of research has focused on developing a completely safe and non-toxic leaching process for gold to replace cyanidation. In this research, a free milling gold ore is leached using copper-citrate-thiosulfate solutions at elevated temperatures, where citrate serves as a stabilizer of cupric ion. Experimental factors such as agitation speed, temperature, initial pH, concentration of copper, citrate and thiosulfate have been investigated. Meanwhile, effects of these parameters on the thiosulfate consumption and Cu2Cit2H−24− complex stability are also examined in the leaching process. The experimental results show that the copper-citrate-thiosulfate system has a similar extraction capacity for gold compared to the traditional cyanidation. The results of kinetic analysis of dissolution rate of gold indicate the leaching process gold from free milling ores may be controlled by the product layer diffusion under the experimental conditions, with an activation energy of 34.48 kJ/mol. The copper-citrate-thiosulfate system has some advantages over cyanidation, such as green, nontoxic and shorter leaching time, although a high leaching temperature above 70 °C is usually required to an acceptable gold extraction. Obviously, the system still needs to be further developed to ensure its commercial viability.

中文翻译：

---

在高温下在柠檬酸铜-硫代硫酸铜溶液中从自由研磨金矿石中浸出金

摘要 在过去的二十年来，大量的研究集中在开发一种完全安全、无毒的黄金浸出工艺来代替氰化。在这项研究中，在高温下使用柠檬酸铜-硫代硫酸铜溶液浸出自由研磨的金矿石，其中柠檬酸盐作为铜离子的稳定剂。已经研究了诸如搅拌速度、温度、初始pH、铜浓度、柠檬酸盐和硫代硫酸盐等实验因素。同时，还在浸出过程中检查了这些参数对硫代硫酸盐消耗和 Cu2Cit2H-24- 复合物稳定性的影响。实验结果表明，与传统氰化相比，铜-柠檬酸-硫代硫酸盐体系对金的提取能力相似。金溶解速率动力学分析结果表明，在实验条件下，自由磨矿浸金过程可能受产物层扩散控制，活化能为34.48 kJ/mol。与氰化法相比，柠檬酸铜 - 硫代硫酸盐体系具有一些优势，例如绿色、无毒和浸出时间较短，但通常需要 70°C 以上的高浸出温度才能获得可接受的金提取。显然，该系统仍需进一步开发以确保其商业可行性。无毒和更短的浸出时间，尽管通常需要高于 70 °C 的高浸出温度才能获得可接受的金提取物。显然，该系统仍需进一步开发以确保其商业可行性。无毒和更短的浸出时间，尽管通常需要高于 70 °C 的高浸出温度才能获得可接受的金提取物。显然，该系统仍需进一步开发以确保其商业可行性。