Bioleaching of low-grade chalcopyritic ore using thermophile bacteria

In recent years, bacterial leaching of copper from low grade chalcopyritic ores has been adverted very much. Different parameters such as the type of microorganisms, pH, temperature have a direct or indirect influence on the bioleaching efficiency of sulfide minerals. Therefore, the main objective of this study was to quantify the potential of thermophile microorganisms for copper recovery from low-grade chalcopyritic ores. Using a representative chalcopyritic low grade copper ore from National Iranian Copper Company with a total copper grade of about 0.344% (CuFeS2= 0.78%), and two different thermophile bacteria, several bioleaching tests were conducted. The final results of lab tests show the potential of extremely thermophiles for bioleaching of copper from this type of low grade ores is higher than moderate thermophiles. At optimum temperature, pH and Fe2+/ Fe3+ ratio, the average copper recovery from low grade ore with extremely thermophiles is up to 17% higher than that with moderate thermopiles.