Galvanic interaction between chalcopyrite and pyrite during bacterial leaching of low-grade waste

摘要: Abstract The bacterial leaching of a low-grade chalcopyrite waste rock in lixiviant containing thermophilic, Sulfolobus-like microorganisms at 60°C and Thiobacillus ferrooxidans 28°C has been compared with the sterile terms copper solubilized elapsed time conversion Fe 3+ 2+ . Bacterial action shown to drastically increase ratio leaching. Direct observations associated pyrite surface corrosion, utilizing scanning electron microscopy, showed that during these sulfides as separate, non-contacting phases, corroded more rapidly than both inoculated media. This effect was pronounced elevated temperature presence bacteria. When were contact, resulting galvanic interaction caused corrode pyrite, which effectively passivated. is thereby enhanced contact pyrite. accelerated corrosion also markedly result oxidation elemental sulfur (formed reaction) sulfuric acid. reaction by catalysis. important implications other galvanic-contact regimes involving metal are identified discussed.