Zinc bioleaching from an iron concentrate using Acidithiobacillusferrooxidans strain from Hercules Mine of Coahuila, Mexico

The iron concentrate from Hercules Mine of Coahuila,Mexico,which mainly contained pyrite and pyrrhotite,was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans(A.ferrooxidans)to determime the ability of these bacteria on the leaching of zinc.The native bacteria were isolated from the iron concentrate of the mine.The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values,pulp density,and the ferrous sulfate concentration on the bioleaching process.The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A.ferrooxidans,which is enriched with a 9K Silverman medium under the optimum conditions ofpH 2.0,20 g/L pulp density,and 40 g/L FeSO4,increases the zinc extraction considerably observed by monitoring duringl 5 d,i.e.,the zinc concentration has a decrease of about 95％ in the iron concentrate.