Application Research Of Manganese Oxide Minerals Resources Reductive Leaching With Pyrite

In this paper, three kinds of manganese oxide minerals resources were carried out using pyrite as the reducing agent on leaching of manganese. The three kinds of manganese oxide minerals resources were the low grade manganese ore tailings, low grade pyrolusite and ocean manganese nodule resources. In the leaching process, the basic principles of chemical leaching process, the effect of various ions in the reaction process, enhanced bioleaching process, efficient microbial cultivation environment, the microorganisms on Mn2+ tolerance and other auxiliary process problemswere studied. The research provides the necessary application basis for the combined process of chemical leaching and microbial leaching.In chemical leaching system, it showed that leaching manganese oxide minerals resources using pyrite as reducing agent is a complex multiphase reaction process. There is a close relationship between the leaching reaction of pyrite and leaching Mn2+ from manganese oxide minerals resources in the solution. Fe3+ has a catalytic effect on chemical the reaction of MnO2-FeS2-H2SO4. Especially in the initial stage of the reaction, the higher the concentration of Fe3+ in solution, the Mn2+ leaching rate is higher.The different reaction style made that the reaction products S and SO42- on the surface of FeS2.The kinetics analysis of Fe3+ catalyzed on the chemical reaction showed that Fe3+ promoted the surface chemical reaction of FeS2 and S solidified layer was producted on the surface of FeS2.The results of microbial enhanced process showed that it could effectively promote the reaction with adding acidithiobacillus ferrooxidans to the leaching process, and which accelerated the leaching rate of Mn2+. The electrochemical analysis of cyclic voltammetry showed that the redox potential of FeS2 was decreased and the potential difference between the oxidation peak and reduction peak was decreased in the bioleaching process. Adding acidithiobacillus ferrooxidans to the leaching process made the reduction of FeS2 more easily.The efficient microbial cultivation showed that adding ceramsite carrier in acidithiobacillus ferrooxidans cultivation can effectively improve the oxidation rate of Fe2+, and which achieved fast cultivation of acidithiobacillus ferrooxidans. Using pyrite as energy in cultivation of acidithiobacillus ferrooxidans showed that acidithiobacillus ferrooxidans bacteria concentration reached 6.4×108 cell/mL after 144h in suitable conditions and the efficiency of cultivation is about 5 times more than the traditional use of ferrous sulfate. Test results showed that acidithiobacillus ferrooxidans has a certain tolerance to Mn2+. When the concentration of Mn2+ is less than or equal to 1g/L, the growth of bacterial activity had little effect. But when the Mn2+concentration at 5g/L to15g/L, the growth of acidithiobacillus ferrooxidans was delayed and when Mn2+ concentration increased to 20g/L, the bacterial metabolism was completely stopped.The research results provided a theoretical basis for optimizing the whole process for chemical and microbial leaching from complex minerals. The research results gived some promote and guides for the industrial application of chemical leaching and microbial leaching process.