Copper recovery from chalcopyrite concentrate by an indigenous Acidithiobacillus ferrooxidans in airlift bioreactor

A mesophilic iron oxidizing bacterium, Acidithiobacillus ferrooxidans has been isolated from a typical chalcopyrite copper concentrate of the Sarcheshmeh Copper Mine in the region of Kerman located in the south of Iran. Effects of some variable parameters such as solid concentration, temperature, initial Fe2+ concentration and pH on bioleaching of sulfide mineral (chalcopyrite) that provided from mentioned mine were investigated. Bioleaching experiments were carried out in two batch air-lift bioreactors with recycling stream. One of the reactors was containing 2 liters of the medium and 10% (v/v) inoculum and in other reactors, sterile bioleaching testes were carried out with concentrate sterilized without inoculum. The results indicate that the efficiency of copper extraction is dependent on all of the mentioned variables. In addition, results show that the effects of solid concentration and temperature were more important than the effect of initial Fe2+ concentration in bioreactor.