XPS study of MnO ₂ minerals treated by bioleaching

Abstract

Abstract XPS has been used to follow the change of the ore surface composition during bioleaching with a mixed culture of microorganisms. In the original sample, the presence of MnO 2 together with silica and alumina is observed. During bioleaching, Mn(IV) is progressively reduced to Mn(II) and signals due to the presence of the microorganisms appear in the C 1s and N 1s spectra. In the residual sample, a considerable amount of Mn associated with the cells of the microorganisms of reprecipitated in the from of the Mn(OH) 2 is present on the surface of the ore. This Mn species can be removed completely by treatment with a dilute soultion of HCI.