Processing of antimony minerals by oxidizing and reducing bacterial processes

The objectives of this work were to evaluate the use of iron- and sulphur-oxidising bacteria Acidithiobacillus ferrooxidans and sulphate-reducing bacteria Desulfovibrio desulfuricans in the biohydrometallurgical processing of gold-bearing antimony sulphide minerals. Experiments were conducted at laboratory scale on a refractory gold-bearing stibnite coming from Santa Rosa de Capacirca Mine, Bolivia. Involved bacteria were used separately at different conditions for the pre-treatment of the aforementioned sample in order to increase the subsequent gold recovery during cyanidation processes. The application of the bacteria Acidithiobacillus ferrooxidans is based on their ability to oxidize and dissolve pyrite and arsenopyrite, thus releasing the entrapped gold particles. The using of the bacteria Desulfovibrio desulfuricans is based on their ability to the bacterially H2S production for the alkaline leaching of stibnite.