Factorial experiments in the study of a biooxidative pretreatment for a conventional cyanidation of a Turkey arsenical gold ore

Cyanide leaching is the traditional process for the extraction of gold from primary raw-materials. When the gold host rock contains high concentrations of sulphides, an oxidative thermal or a chemical pretreatment is often needed to access precious metal particles. Biooxidative leaching may be an interesting alternative, if compared with the environmental effects and costs of the conventional pretreatment processes, to liberate gold from the sulphide matrix and then to make it amenable to cyanidation. Bioleaching with Thiobacillus ferrooxidans and Thiobacillus thiooxidans has been investigated at bench scale on a gold-bearing arsenopyrite (2 g/t Au) ore coming from Gölcück Mine in Turkey. In this work the main factors that can influence the biooxidative pretreatment, in order to enhance the gold recovery in a conventional cyanidation process, have been tested using factorial experiments.