Abstract

FRANCISCO JR, Wilmo E.; BEVILAQUA, Denise  and  GARCIA JR, Oswaldo. Microbiological oxidative dissolution of a complex mineral sample containing pyrite (FeS₂), pyrrotite (Fe_1-xS) and molybdenite (MoS₂). Quím. Nova [online]. 2007, vol.30, n.5, pp. 1095-1099. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422007000500008.

This work aims to study the oxidation of a complex molybdenite mineral which contains pyrite and pyrrotite, by Acidithiobacillus ferrooxidans. This study was performed by respirometric essays and bioleaching in shake flasks. Respirometric essays yielded the kinetics of mineral oxidation. The findings showed that sulfide oxidation followed classical Michaelis-Menten kinetics. Bioleaching in shake flasks allowed evaluation of chemical and mineralogical changes resulting from sulfide oxidation. The results demonstrated that pyrrotite and pyrite were completely oxidized in A. ferrooxidans cultures whereas molybdenite was not consumed. These data indicated that molybdenite was the most recalcitrant sulfide in the sample.

Keywords : bioleaching; A. ferrooxidans; mineral sulfides.