Cyanide-free Gold Extraction by Biology Oxidization --- Thiourea Leaching and Resin-in-Pulp

The project combined bio-oxidizationa pretreatment of refractory gold ore with thiourea leaching, for the sake of efficient utilization of the refractory gold resources with micro-fine particles, and at the same time solving the environment pollution problem of cyanide leaching, reaching the target of “high efficiency and environment protection” in exploitation of the refractory gold resources.

Combined bio-oxidization with the cyanide-free process of thiourea leaching, and using resin-in-pulp and cycling of the tailing solution, this technology improves the leaching recovery while cuts down operational consumption and cost, which techno- economic indices of 100 kg/d scale up test reached the advanced level of the world standards in gold extraction from refractory ore, and is at the leading level in gold mining production.

Because of utilizing cyanide free extracting process, environment protection is significantly improved. This method will gradually replace cyanidation method, especially in the environment sensitive regions.