INTERMEDIATE REACTION PROMOTING BACTERIAL LEACHING OF SULFIDE ORES

Ferrousion, elemental sulfur and their mixtures were investigated as energy substrates affecting the metabolism of T. ferrooxidans N1. Also the roles of Fe 2+ and of Fe 3+ reaction with water in the leaching of sulfide ores were investigated. Based on scanning electron microscopy and theoretical analysis,a new leaching mechanism different from the previously postulated`direct oxidation mechanism'and `indirect oxidation mechanism' for bacterial leaching was proposed.Sulfur metabolism of T. ferrooxidans N1 was assumed to greatly influence bacterial leaching of sulfide minerals. Experimental results showed that sulfur metabolism of T. ferrooxidans N1 produced H +,and developed the necessary acidic condition for the oxidative metabolism of Fe 2+ in the liquid phase.Reactions among intermediates in the energy metabolism of T. ferrooxidans N1 promoted growth and facilitated sulfide mineral leaching and also altered hydration of ferric iron ions. Therefore the enzymatic intermediates in the metabolism of T. ferrooxidans N1 played a central role in the bacterial leaching process.