Exploring the influence of DMSA on thiosulphate leaching of gold ores

在从矿石中提取金的实践中，氰化物是最常用的浸出剂，因为它对金的选择性，优异的浸出动力学，以及易于通过吸附在活性炭粗颗粒上从溶液中回收。然而，氰化物不适合从含碳矿石中提取金，其毒性引起了越来越多的环境关注。由于这些缺点，有必要确定毒性较低的氰化物替代品，适合从各种各样的矿石中浸出金。在寻找氰化物替代品的过程中，硫代硫酸盐已被确定为合适的候选物，在氢氧化铵和硫酸铜作为催化剂的情况下，硫代硫酸盐显示出良好的金的初始浸出动力学。然而，这些添加剂的存在会阻碍长期浸出率，因为它们产生的分解产物会吸附在金表面，干扰浸出机制。最近的一些研究表明，添加适量的有机添加剂可以提供协同效应，提高硫硫酸盐系统中金的浸出率。在目前的研究计划中，我们将进一步研究我们观察到的硫代硫酸盐与少量的中-2,3-二巯基琥珀酸（DMSA）混合时对金浸出的改进。该研究将在实验室控制的溶液以及与巴里克黄金公司工业相关的电解质中进行。该研究可为优化硫代硫酸盐对DMSA的添加量，以提高实际矿石的浸出效果提供依据。此外，这项研究将由学生进行，他们将学习金浸出的工业实践，并应在冶金部门培养高素质的人员。

In the practice of extracting gold from ores, cyanide is the most common choice of leaching agent because of its selectivity for gold, excellent leaching kinetics, and ease of recovery from solution by adsorption onto coarse particles of activated carbon. However, cyanide is not suitable for extracting gold from carbonaceous ores and there is increasing environmental concern regarding it's toxicity. Because of these drawbacks, there is a need to identify less-toxic alternatives to cyanide that are appropriate for leaching gold from a wide variety of ores. In the search for an alternative to cyanide, thiosulphate has been identified as suitable candidate and shows good initial leaching kinetics for gold provided that ammonium hydroxide and copper sulphate are used as catalysts. However, the presence of these additives can hinder long-term leaching rates because they produce decomposition products that can adsorb on the gold surface and interfere with the leaching mechanism. Some recent studies have shown that adding controlled amounts of organic additives can provide a synergistic effect that improves the leaching rate of gold in thiosulphate systems. In the current research proposal, we will further study an improvement to gold leaching that we have observed when thiosulphate is mixed with small amounts of meso-2,3-dimercaptosuccinic acid (DMSA). The study will be performed in both laboratory controlled solutions as well as electrolytes that are industrially relevant to Barrick Gold corporation. The research may lead to the optimization of the amount of DMSA that should be added with thiosulphate for improved leaching in real ores. Moreover, the research will be performed by students who will learn the industrial practices of gold leaching and should result in personnel that are highly qualified in the metallurgical sector.