Abstract:For the pretreatment process of refractory gold ore, bio-oxidation method has become a relatively mature pretreatment technology because of its advantages of environmental protection, simple operation and low investment in equipment. In the process of gold extraction after gold ore pretreatment, thiourea leaching has become a promising non-cyanide gold extraction method because of its advantages of environmental protection, non-toxicity, high efficiency and fast leaching speed. Therefore, the combined process of bio-oxidation pretreatment and thiourea leaching of gold has become a research hotspot for gold leaching from refractory gold ores because of its advantages of environmentally friendly, mild conditions and high leaching efficiency. In this paper, the principle of bio-oxidation pretreatment technology, the reaction mechanism and research progress of thiourea gold leaching, and the research status and application prospect of the combined process of bio-oxidation pretreatment and thiourea gold leaching are introduced in detail. The factors affecting the leaching of gold with thiourea were studied experimentally. The optimum leaching conditions of thiourea under this system were obtained as follows: temperature 25 ℃, pH 1.5, liquid-solid ratio 5:1, thiourea concentration 25 kg/t, leaching time 5 h, stirring speed 350 r/min.