There are significant technical challenges/shortcomings in recovering gold from thiosulphate leach solutions. This study presents a new approach for the recovery of gold from ammoniacal thiosulphate leach solutions using an environmentally friendly organo-sulphide reagent, trimercapto--triazine (TMT; CNS). Precipitation of gold by TMT was investigated using synthetic gold and multi-metal solutions (Au-Ag, Au-Cu, Au-Ag-Cu) to investigate the effect of the co-presence of metals commonly present in thiosulphate leach solution. The effect of TMT concentration (by up to 115 mM), temperature (25–60 °C) and ammonia (0.25–1 M NH) on the precipitation of gold was also investigated. The results showed that gold precipitation with TMT was relatively low (i.e., limited to only 37.7% over 15 min) from the solution containing only gold. However, the presence of silver and/or copper significantly improved the precipitation of gold. Silver concentrations at ≥20 mg/L led to a complete recovery of gold in 15 min, producing stable gold precipitates. The results have also indicated that silver readily precipitates when compared to gold. The effectiveness of the TMT precipitation process was also tested on a real leach solution from which complete recovery of gold and silver was readily achieved. The findings demonstrated that gold could be readily but unselectively recovered by precipitation with TMT from ammoniacal thiosulphate leach solutions containing silver, in particular, at the expense of co-precipitation of other metals such as copper and zinc.

中文翻译：

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金属对三巯基均三嗪 (TMT) 沉淀从氨硫代硫酸盐浸出液中回收金的影响

从硫代硫酸盐浸出溶液中回收金存在重大的技术挑战/缺点。这项研究提出了一种使用环保的有机硫化物试剂三巯基三嗪（TMT；CNS）从氨硫代硫酸盐浸出溶液中回收金的新方法。使用合成金和多金属溶液（Au-Ag、Au-Cu、Au-Ag-Cu）对 TMT 沉淀金进行了研究，以研究硫代硫酸盐浸出溶液中常见金属共存的影响。还研究了 TMT 浓度（高达 115 mM）、温度（25–60 °C）和氨气（0.25–1 M NH）对金沉淀的影响。结果表明，TMT 从仅含金的溶液中沉淀出的金相对较低（即，15 分钟内仅为 37.7%）。然而，银和/或铜的存在显着改善了金的沉淀。银浓度≥20 mg/L 导致金在 15 分钟内完全回收，产生稳定的金沉淀物。结果还表明，与金相比，银更容易沉淀。 TMT 沉淀工艺的有效性也在真实的浸出溶液中进行了测试，从该浸出溶液中很容易实现金和银的完全回收。研究结果表明，通过用TMT从含银的氨硫代硫酸盐浸出溶液中沉淀，可以很容易但非选择性地回收金，特别是，以铜和锌等其他金属的共沉淀为代价。