Abstract:To make sure the dissolution characteristics of apatite in the chalcopyrite bioleaching system and the influence on the chalcopyrite leaching efficiency, the apatite with particle size of less than 43 μm, chalcopyrite with 74 μm and Acidithiobacillus ferrooxidans (At.f) were used to prepare a bioleaching system. And the influence of different At.f inoculation amount on the apatite dissolution rate and chalcopyrite leaching effect were studied. The results show that chalcopyrite leaching efficiency can be improved when there exists PO₄^3- with low concentration in the bioleaching system. And PO₄^3- reaches the lowest concentration of 0.62 mg/L in the bioleaching system when the At.f inoculation amount is 5%, and the final chalcopyrite leaching rate reaches the highest of 57.4%, which is 30% higher than that in the bioleaching system with the highest concentration of PO₄^3-. Scanning electron microscope (SEM), energy dispersive spectroscope and X-ray diffraction (XRD) analyses before and after the bioleaching show that, there is not any obvious erosion on the apatite surface after leaching, while obvious erosion exists on the chalcopyrite surface and new compound ammoniojarosite generates in the leaching residue. And the precipitates newly generated can be absorbed by apatite, low concentration PO₄^3- in the bioleaching system can improve the leaching of chalcopyrite.

Key words: chalcopyrite; apatite; bioleaching; Acidithiobacillus ferrooxidans