Bio-dissolution of pyrite by Phanerochaete chrysosporium
(1. School of Metallurgy, Northeastern University, Shenyang 110819, China;
2. Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China)
Abstract: The dissolution of pyrite was studied with Phanerochaete chrysosporium (P. chrysosporium). This fungus resulted in the dissolution of 18% iron and 33% sulfur. The oxidization layer was formed on the pyrite surface, which probably consisted of iron oxide, iron oxy-hydroxide, iron sulfate, elemental sulfur and mycelia. The electrochemical characteristics of pyrite were studied in the systems without and with P. chrysosporium. P. chrysosporium could accelerate the dissolution of pyrite by decreasing pitting potential and polarization resistance plus improving polarization current, corrosion potential and corrosion current density. The dissolution of pyrite is the combined effect of enzymes, hydrogen peroxide, ferric iron and organic acids. Enzymes attack the chemical bonds by free radicals. Organic acids dissolve pyrite by acidolysis and complexolysis. Enzymes and hydrogen peroxide play an essential role in this process.
Key words: Phanerochaete chrysosporium; pyrite; bio-dissolution; Carlin-type gold ores; electrochemistry