Abstract:

In the hypergenesis processes, the presence of Acidothiobacillus ferrooxidans can effectively promote the dissolution of chalcopyrite. Previous studies indicate that the dissolution mechanisms of chalcopyrite include direct and indirect mechanism. However, the contribution of each mechanism to the mineral dissolution is still in controversy. By the employment of microfiltration membrane to segregate minerals from bacteria, this study simulated and compared the dissolution behaviors of chalcopyrite in the conditions of indirect and direct contact with Acidothiobacillus ferrooxidans. The variations of Cu2+ concentrations of the solution of both experiments were analyzed by using inductively coupled plasmaatomic emission spectrometry (ICPAES), and the surface morphology of chalcopyrite and secondary precipitation were observed by using scanning electron microscope (SEM). This study indicates that Acidothiobacillus ferrooxidans can clearly promote the dissolution of chalcopyrite through either mechanisms, and that the effect of direct mechanism on the dissolution is more efficient than that of indirect one.

Key words:

chalcopyrite; dissolution; Acidothiobacillus ferrooxidans; direct mechanism; indirect mechanism