Dissolution of Pyrite Particles by Chemical Oxidation and Bioleaching

Dissolution of pyrite by chemical oxidation and bioleaching were studied with using short-term batch experiments. The results show that the rate of oxidative dissolution of pyrite increases with the increasing concentration of ferric in ferric sulfate solutions. With the corresponding in the bioleaching, the leaching rate of pyrite is markedly affected by the Eh of the solution. The ferric/ferrous ratio controls the relative rate of the oxidation reactions involved in the process. Additionally, the leaching rate of pyrite is controlled by the pH. The phase analysis of products indicated that S-2(2-) oxidation can produce S-0 and SO42- under these conditions. On the basis of predecessors and using these species, the simplest expected oxidation mechanism is S2O32- regarded as the intermediate mechanism during the oxidation process.