Bioleaching of cobalt from magnetite-rich cobaltite-bearing ore

Abstract Cobaltite (CoAsS) is a strategically important mineral. This work investigated the bioleaching of cobaltite-bearing magnetite-rich ore. The bioleaching of cobaltite was carried out with mixed mesophilic and moderately thermophilic cultures at 4, 8, and 12% pulp densities in shake flasks. The bioleaching with mesophiles at 8% pulp dissolved up to 89% of the cobalt content, higher than the bioleaching of 4% pulp and abiotic control test. Additional Fe3+ in the leach solution increased cobalt dissolution in the control test. The bioleaching by moderate thermophiles reached 97% cobalt dissolution in 16 d contact time. Kinetic modeling indicated that the controlling step of bioleaching with moderate thermophiles was the chemical reaction, while the diffusion was the rate-limiting factor for the bioleaching with mesophiles.