Research On The Electrochemical Mechanism Of Chalcopyrite In Bioleaching Process

Chalcopyrite (CuFeS2), which is the main copper ore in China, is low-grade ore. Itwill produce a large number of low-grade ore, waste rock and tailings in the miningprocess. The traditional beneficiation and metallurgy process of CuFeS2could give rise toa number of problems, such as high cost and serious environmental pollution.Bioleaching, as novel hydrometallurgy technology developed in recently, is one of themost powerful method for CuFeS2leaching. However such as passivation, have appearedin process of CuFeS2bioleaching.Cu leaching efficiency is hardly promoted.In this research, natural chalcopyrite was used as the research object, and dynamicpolarization curve test and electrochemical impedance test were carried on to study theinfluence of leaching conditions factors, such as acidity, temperature, concentration ofFe2+ions and Cu2+ions in leaching process. Chalcopyrite bioleaching experiments werecarried out as well. Bioleaching slag was analyzed by electrochemical analysis method.The results showed that low pH value and high concentration of Fe2+undercooperative effect between C and Fe ions could promote the leaching rate of CuFeS2.Higher temperature would enhance corrosion current density of CuFeS2surface when theleaching temperature below40oC. Whereas its corrosion current density decreased withthe temperature increased when the leaching temperature above40oC. There are noobviously changes of chalcopyrite leaching rate whether Cu2+ions existed or not. Theoptimum chalcopyrite leaching conditions is: pH=1.0, concentration of Fe2+50g/L,leaching temperature40oC.There are two stages of chalcopyrite in its bioleaching. At the prior period of itsbioleaching, leaching rate of chalcopyrite accelerated with the redox potential of leachateincreased sharply. And the pH of leachate got up first and then down. At the last period,owing to the accumulation of S0and other precipitate, as well as the enhancement ofdiffusion control, its leaching rate was decreased. Compared with the slags obtained bychalcopyrite bioleaching with C catalysis or not, higher leaching rate of chalcopyrite willbe achieved with C catalysis.Figure39; Table10; Reference55...