The Kinetics Of Bacterium Community During The Bioleaching Of Pyrite With Mixed Bacterium

The purpose of this study was to investigate on the community shifting during the bioleaching of pyrite with mixed bacteria.In this work, A. ferrooxidans、A. thiooxidans、A. caldus、L. ferrooxidans and S. thermosulfidooxidans were used to bioleach pyrite under different temperatures and initial pH values.The pH value,_concentration of bacteria,ion redox potential and ion concentration of the solution were analyzed.The microbial diversity in the bioleaching process was studied with DGGE method.The surface morphological was also analyzed by scanning electron microscopy(SEM).The change of pH value, concentration of bacteria,ion redox potential and ion concentration of the solution is similar between bioleaching process at different initial pH values,which was depended on the prodominant bacteria of logarithmic phase in the solution,which may highly raise the value of redox potential and the total concentration of iron,lower the value of pH and the concentration of Ferrous ion.The prodominant bacteria was changed with the change of temperature at the same pH value. A. ferrooxidans、A. thiooxidans were the dominant bacterias at30℃and35℃; L. ferrooxidans was also found at35℃, which became the private bacteria at40℃with A. caldus and S. thermosulfidooxidans, which are the private bacterias at40℃and45℃.The microbial community on the surface of pyrite slag was similar with that in the bioleaching solution,which was not stable because of the dropping of the bacteria from the surface.