Copper Recovery by Bioleaching of Chalcopyrite: A Microcalorimetric Approach for the Fast Determination of Bioleaching Activity

Low grade copper ores containing chalcopyrite are increasingly used for copper recovery via biomining. Since metal sulfide oxidation is an exothememic process, bioleaching activity can be measured due to the heat output by microcalorimetry, which is a non-destructive and non-invasive method. The bioleaching activity of pure cultures ofSulfolobus metallicus,Metallosphaera hakonensisand a moderate thermophilic enrichment culture on high grade chalcopyrite was evaluated. Chalcopyrite leaching by microorganisms showed a higher copper recovery than sterile controls. Chemical chalcopyrite leaching by acid produced heat due to the exothermic reaction, the heat output was increased while metal sulfide oxidation by microorganisms.