Study on Microbially Mediated Dissolution of Arsenopyrite by Acidithiobacillus ferrooxidans and Its Suppression by Two Organic Matters.

Microbially mediated dissolution of arsenopyrite by Acidithiobacillus ferrooxidans and its suppression by two kinds of organic matters was investigated. Results are summarized as follows:(1) In the microbially mediated dissolution of arsenopyrite by Acidithiobacillus ferrooxidans, the dissolved arsenic species inhibited the growth and activity of the microorganism, therefore, the dissolution rate was slow in comparison with those of pyrite.(2) In the presence of low concentrations of tannic acid, the growth and activity of the A. ferrooxidans were not inhibited but accelerated.(3) The presence of extractant after autoclaving Acacia Mangium, which contains trace amounts of poly-phenolic derivatives, leads the fast consumption of oxygen and strongly reducing function, therefore, quickly inhibited the first oxidation of arsenopyrite by oxygen. It is fairly different from the suppression mechanism by tannic acid.