Recovery of gold from sulfide refractory gold ore: Oxidation roasting pretreatment and gold extraction

Abstract

Recovering gold from sulfide refractory gold ore has been an important guarantee for the sustainable development of gold industry, while there are many challenges in the treatment of sulfide refractory gold ore, such as environmental pollution and low gold recovery. In this study, A novel method for gold recovery from refractory gold ore was proposed with the purpose of improving recovery efficiency of gold and reducing environmental pollution. The method consisted of two stages roasting for arsenic and sulfur removal, gold recovery by thiourea leaching, followed by an enhanced chlorination roasting for gold recovery in the presence of pyrite. In the two-stage roasting process, the phase transition of FeAsS and FeS2 during the roasting process was analyzed. In the first stage roasting process, the removal efficiency of arsenic reached 96.98% with only 43.07% sulfur was removed. We achieved removal efficiency of 97.19% for sulfur and 84.11% of gold was exposed during the second stage roasting process. The thiourea leaching combined with pyrite enhanced chlorination roasting was first proposed to effectively extract gold from the second stage roasting slag, and the pyrite shown a great role in promoting gold extraction during chlorination roasting. In this process, gold could be effectively recovered from the sulfide refractory gold ore with a recovery efficiency of 98.06%.