Leaching of Precious Metals from Complex Sulphide Ores. On the Chemistry of Gold Lixiviation by Thiourea

In this paper, the chemistry involved with the leaching of gold by acidic thiourea solutions has been reviewed. The thermodynamics and kinetics of the complexation of thiourea with gold, silver and other associated metals, as well as the degradation of the thiourea itself were discussed. Some of the relevant technical aspects of thiourea leaching were considered. The available data were analyszcd in order to establish the rate determining step for gold dissolution process and the dependence of thiourea consumption on leaching conditions.