锌粉置换回收铜-乙二胺-硫代硫酸盐浸金体系中金的研究

探讨锌粉置换法从Cu~(2+)-en-S_2O_3~(2-)浸金液中回收金,通过绘制物种平衡分布图和计算相关电对的电极电势,考察置换回收金的可行性和可能存在的副反应。结果表明,在Cu~(2+)-en-S_2O_3~(2-)浸金体系中锌可与Au(S_2O_3)_2~(3-)反应置换出金单质,浸金液中的铜亦可被锌粉还原从而造成锌粉的消耗,锌的主要产物为Zn(OH)_2和Zn(en)_3~(2+)。对置换后的锌粉进行扫描电子显微镜(SEM)分析,发现其表面有氧化物和硫化物生成。置换实验结果表明,置换时间在10~15 min内为宜,溶液pH值为10时效果最好,锌粉用量不宜太多,增加硫代硫酸盐浓度对整体反应影响不大。

Recovery of Gold from Ethylenediamine - Thiosulfate Leaching Solutions through Cementation with Zinc Powder

This paper discussed the recovery of gold from Cu2 -en-S2O32- leaching gold system using zinc powder as reducing agent. The feasibility and possible side effects of the gold recovery were investigated by mapping species balance maps and calculating the electrical potential of the relevant electrical pairs. The results showed that in the Cu2 -en-S2O32- gold leaching system, zinc could react with Au(S2O3)23- to replaced gold, and the copper in the gold bath could also be reduced by zinc powder, which led to the consumption of zinc powder, and the main product of zinc was Zn(OH)2 and Zn(en)32 . The analysis on replaced zinc powder with SEM scanning electron microscopy showed that there were oxides and sulfides formed on surface of the zinc powder. The results of the displacement experiment showed that it would be better to keep the replacement time between 10 minutes and 15 minutes, the optimum pH value was 10, and the amount of zinc powder should not be too much, increased the concentration of thiosulfate had little effect on the cementation.