Effect of thiamine hydrochloride on the redox reactions of iron at pyrite surface. (Fourth quarterly techical progress report, September 1990--November 1990)

摘要

The present investigation is a part of our studies on the electrochemical aspects of pyrite bioleaching involving Thiobacillus ferrooxidans. Previously (1,2) we have examined the effect of T. ferrooxidans and their metabolic products on the redox reactions of Fe(sup 2+)/Fe(sup 3+) couple at the pyrite surface. Results obtained suggest that beyond 1. 5 days during their growth in a batch fermenter, the bacteria and their metabolic products completely cover the pyrite surface and shut down all electron transfer across the electrode-solution interface. In addition, it has been observed that the bacteria serve as the nucleation site for jarosite formation, which is found detrimental to bioleaching. In the present work we have focussed on the effect of the presence of vitamins on the redox chemistry of iron. Our examination of the effect of the presence of thiamine hydrochloride in the redox behavior of Fe(sup 2+) /Fe(sup 3+) at the pyrite surface has revealed that thiamine hydrochloride does not undergo chemical interaction with ferrous or ferric iron. However, it may adsorb onto the pyrite surface causing polarization of the pyrite electrode.