TITLE:
Efficacy of Bacterial Adaptation on Copper Biodissolution from a Low Grade Chalcopyrite Ore by A. ferrooxidans
AUTHORS:
. Abhilash, K. D. Mehta, Bansi D. Pandey
KEYWORDS:
Bioleaching; Low-Grade Ore; Chalcopyrite; Acidithiobacillus ferrooxidans
JOURNAL NAME:
International Journal of Nonferrous Metallurgy,
Vol.1 No.1,
April
28,
2012
ABSTRACT: A low-grade ore containing ~0.3% Cu, remains unutilized for want of a viable process at Malanjkhand Copper Project (MCP), India in which copper is present as chalcopyrite associated with pyrite in quartz veins and granitic rocks. In order to extract copper from this material, bioleaching has been attempted on bench scale using Acidithiobacillus fer-rooxidans (A. ferrooxidans) isolated from the native mine water. The enriched culture containing A. ferrooxidans when adapted to the ore and employed for the bioleaching at 5% (w/v) pulp density, pH 2.0 and 25°C with three particle sizes viz.150 -76 μm, 76 - 50 μm and SCE) from 530 to 654 mV in 35 days. Under similar conditions, the unadapted strains gave a recovery of 44.0% for SCE from 525 to 650 mV. On using unadapted bacte-rial culture directly in shake flask at pH 2.0 and 35°C temperature and 5% (w/v) pulp density (PD) for 9 cells/mL in 35 days. The higher bio-recovery of copper with the adapted bacterial culture may be attributed to the improved iron oxidation (Fe2+ to Fe3+) exhibiting higher ESCE as compared to that of unadapted strains.