Bioleaching of a low grade Indian Chalcopyrite ore by Microbial consortium

Abstract

Mesophilic bacteria namely, Acidithiobacillus ferrooxidans (A.ferrooxidans) and Acidithiobacillus thiooxidans (A.thiooxidans) were isolated in 9K media from the mine water of Malanjhkhand Copper Project (MCP), India. These strains were used as such (without adaptation) on the ore for the bio-leaching of copper from the low grade chalcopyrite ore (0.27% Cu). With the use of unadapted bacterial consortium in the ratio of 4:1 (A.ferrooxidans and A.thiooxidans), the maximum copper recovery of 69.4% was obtained in 30 days at pH 1.5, 35oC temperature, 10% (w/v) pulp density with particles of <50 µm size. High copper recovery at pH 1.5 may be correlated with the increase in redox potential from 340-642 mV and increase in bacterial population from 3x107 to 6.07x108 cells/mL in 30 days. This research has shown emphasis on the possibility of achieving high copper extraction in the presence of native strains of A.ferrooxidans and A.thiooxidans.