ABSTRACT
The aim of the present experimental study was to ascertain - in preliminary manner - the best conditions for leaching, by alkaline solution, of a refractory gold-bearing stibnite (Sb2S3) coming from South America. The solutions were constituted by sodium sulfide (Na2S) and sodium hydroxide (NaOH). After leaching, antimony (Sb) has been recovered by electrodeposition, in order to increase the economical convenience of the subsequent gold extraction. Antimony recovery was about 75 % Sb. Metallic antimony, with high grade of purity, has been obtained. It was revealed that, the chemical pretreatment, improve the gold extraction yield and favours a low consumption of reagents: after cyanidation low recovery has been obtained without pretreatment (about 35 % Au), while a high gold recovery was achieved in the case of the pretreated samples (about 80 % Au), considering also the subsequent steps of carbon concentration-purification and electrowinning. In conclusion, the technical feasibility of the alkaline leaching pretreatment prior to the conventional cyanidation has been demonstrated.
