Bioleaching And Corrosion Electrochemistry Of Typical Sulphide Minerals

Bioleaching has some advantages of using resourcefully, low cost and little environmental pollution, so it has already been-researched widely and been applied to the industry domestic and abroad. Four kinds of sulfides single minerals-pyrite, chalcopyrite, pyrrhotite, pentlandite were studied. The bioleaching of sulfide minerals were studied by bioleaching bacteria, the elcetrochemistry mechanisms of suilfide mineral and anode behavior wes studied using carbon paste electrode in acid solution systematically.The experiment adopted HQ0211 bacteria, which was mostly made up of Thiobacillus ferrooxidans. The bacteria cells in the mid-log phase of growth were full, uniform and well-proportioned. At the same time, this period was the optimum time for inoculation. In the steady phase of growth the bacteria cells were curly and asymmetric. Then the bacteria cells were variform and misshapen in the dying phase, the thallis became autolyzing.To the pure mineral of pyrite, chalcopyrite, pyrrhotite, pentlandite, the bioleaching research was carried out in the absence of bacteria and in the presence of bacteria. The effect of various factors on leaching were investigated. The result indicated, the leaching rate of sulfide minerals in the presence of bacteria was higher than that in the absence of bacteria.The intermediate reactions of the anode process of pyrite, chalcopyrite, pyrrhotite, pentlandite, which are measured by CV test. When the bacteria in presence, company with the peak current and reversibility of reaction increasing, The bacteria has contribution to the oxidation of element sulfur formatted during the interniediate process.Tafel curve study showed that the addition of bacteria can make the corrosion potential and corrosion current of sulfide minerals decrease. The corrosion potential elevates indicated, the chemical reaction Gibbs of sulfide minerals in the presence of bacteria was reduced. The corrosion current elevates indicated, sulfide minerals'corrosion reaction rate enhancement was enhanced.The alternating impedance method showed that the anode behavior of pyrite,chalcopyrite, pyrrhotite, pentlandite was a mixed control process by electro-chemical reaction and charge diffusion. The polarized resistance of sulfide minerals in the presence of bacteria was reduced, it showed that the addition of bacteria can contribution to decomposition of anode.