Effect of oxygen and lead nitrate on the cyanidation of a sulphide bearing gold ore

Various leaching parameters such as particle size, cyanide concentration, pH and the application of oxygen and lead nitrate have been investigated for the recovery of gold from an ore containing pyrite and small amounts of pyrrhotite and chalcopyrite. plication of lead nitrate in combination with oxygen generated the best results. Gold extraction of 96% can be obtained with cyanide consumption of 0.51 kg/t and lime consumption of 0.60 kg/t in 24 hours. A four hour pre-leach followed by cyanidation is required (free cyanide concentration 480 ppm, pH 10.5, lead nitrate 200 g/t and 16 ppm O2). Compared to the plant performance that uses different leaching conditions, these results show three fold reduction in cyanide consumption and a 20% enhancement of gold leaching kinetics.