Gold recovery from Pyrrhotite by Bioleaching and Cyanidation: a preliminary study using statistical methods

Gold is usually recovered by cyanidation, however the efficiency of this technology, in the case of refractory ores, is low. The aim of the present work has been to study the main factors that can influence the biooxidative pretreatment by factorial experiments, in order to increase the gold recovery in a conventional cyanidation process. The biological treatment with Thiobacillus ferrooxidans has been investigated at bench scale on a gold-containing pyrrhotite (10 g/t Au) ore coming from the Atoroma mine in Bolivia.