The Bioleaching Of Different Genetic Type Pyrite And Mineralogical Effect Mechanism Review

The biooxidation of pyrite is main research object in microbial pretreatment of bearing gold pyrite. The differences of physical property of different geo-genetic pyrites will play an important role in bioleaching results. In this paper three genetic pyrites as research objects and test stains including L. ferriphilum, S. thermosulfidooxidans and A. manzaensis were performed bioleaching experiments to investigate the differences of three pyrites leaching results. Effect of mineral properties of different geo-genetic pyrites on bioleaching was discussed in terms of mineralogy combined with semiconductive test and texture test.The research results of physical properties of pyrites showed that geo-genetic of pyrite from Leiyang was high temperature hydrothermal type, and coarse particle with good crystallinity was an n-type semiconductor. The geo-genetic of pyrite from Tongren was low temperature hydrothermal type and particle with good crystallinity was a p-type semiconductor, while that of pyrite from Wenshan was sedimentary coal type and fine particle with poor crystallinity is a p-type semiconductor.Bacterial adsorption quantity and Zeta potential measurement results of different geo-genetic pyrites indicated that little differences of adsorption quantity on two geo-genetic p-type pyrites, and adsorption quantity on p-type pyrite was less than that of n-type pyrite. The isoelectric point (IEP) of pyrites shifted towards to that of bacteria after interacting with bacteria, and that of high temperature hydrothermal n-type pyrite shifted most obviously, while that of coal sedimentary p-type pyrite changed little, which were consistent with adsorption quantity change rule.Bioleaching experiment indicated that high temperature hydrothermal n-type pyrite was almost insoluble, while leaching rates of low temperature hydrothermal and coal sedimentary two p-type pyrites could reach15.25%～27.92%and27.50%～34.59%respectively by different stains after21days.The analysis in terms of mineralogical factors showed that semiconductive type was the main reason that led to the significant difference among surface properties and leaching behavior of different geo-genetic pyrites, and different pyrite surface active atoms density caused by different cry stall inity was the key factor that resulted in different leaching behavior for same semiconductive type pyrites.