A clean and efficient innovative technology for refractory sulfide gold ore: In situ gold extraction via self-generated thiosulfate

Abstract

Green non-toxic extracting gold from refractory sulfide gold ore using thiosulfate is an essential guarantee for the sustainable development of the gold industry. However, there are many bottlenecks, including environmental pollution from traditional pretreatment of sulfide gold ore and high consumption of chemical thiosulfate. Herein, a clean and efficient innovative technology for the comprehensive utilization of refractory sulfide gold ore (high sulfur and high arsenic) was first proposed. For high arsenic sulfide gold ore, a sufficient sulfur source (addition of pyrite or sulfur) could be supplemented, and then thermal activation pretreatment for thiosulfate generation. This alternative technology can prevent the volatilization of hazardous gases (SO2 and As2O3) and instead collect them as less harmful solids (S8 and As2S3). Moreover, thermal activation pretreatment of this sulfide gold ore significantly enhances the oxidation capacity and results in the generation of sufficient thiosulfate (286 mM). The pretreatment also breaks down the sulfide inclusions to expose the encapsulated gold, which can be in situ extracted via self-generated thiosulfate. As a result, a gold extraction rate of 80.2% was achieved for this refractory sulfide gold ore without the addition of chemical thiosulfate. This innovative technology is of high academic and industrial interest, addressing the high thiosulfate consumption and promoting the industrialization of green gold extraction from refractory sulfide gold ore.