Exploring the influence of DMSA on thiosulphate leaching of gold ores

在从矿石中提金的实践中，氰化物是最常用的浸出剂，因为它对金具有选择性，浸出动力学良好，而且易于通过吸附在粗颗粒活性碳上从溶液中回收。然而，氰化物不适合于从碳质矿石中提金，其毒性越来越受到环境的关注。由于这些缺点，需要找到毒性较低的氰化物替代品，适合于从各种矿石中浸出黄金。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者，并且在以氢氧化铵和硫酸铜为催化剂的情况下，对金的初始浸出动力学良好。然而，这些添加剂的存在可能会阻碍长期的浸出率，因为它们会产生能够吸附在金表面的分解产物，并干扰浸出机理。最近的一些研究表明，在硫代硫酸盐体系中加入适量的有机添加剂可以产生协同效应，提高金的浸出率。在目前的研究方案中，我们将进一步研究我们观察到的硫代硫酸盐与少量的Meso-2，3-二硫代琥珀酸(DMSA)混合时对金浸出的改善。这项研究将在实验室控制的溶液和与巴里克黄金公司有关的电解液中进行。这项研究可能会导致在实际矿石中添加DMSA以改善实际矿石浸出的最佳加入量。此外，这项研究将由学生进行，他们将学习黄金浸出的工业实践，并将培养出冶金行业的高素质人员。

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.