Acidithiobacillus ferrooxidans: performances on the low-grade polymetallic oxidized-manganese and sulfur-nickel ores redox system

Abstract

A simultaneous bioleaching process to extract nickel, cobalt, copper and manganese from polymetallic nodule and low-grade nickel sulfide ore by using Acidithiobacillus ferrooxidans is proposed in this study. Thermodynamic investigations and potential analysis showed that the selective leaching of Ni, Co, Cu, Mn is feasible. The electrochemical measurements reveal that A. ferrooxidans increases the potential difference between nodule anode and sulfide cathode. A. ferrooxidans leads to the negative shift of corrosion potential and the increment in electron release of the sulfur-containing substance, and accelerates the electron transfer and exchange current density in the nodule digestion. Under the optimal conditions, in the presence of A. ferrooxidans the final pregnant solution contained 0.86 g Ni/L, 56 mg Co/L, 0.62 g Cu/L, and 5.81 g Mn/L with the improvement of 5.1%, 4.1%, 5.9% and 4.9% referring to operation with sterile solution. The leaching rate of Ni, Cu, Co and Mn increases respectively by a factor of 0.17, 0.48, 0.10, and 0.093 in the A. ferrooxidans and Fe(III) medium relative to the Fe(III) alone, with a mean of 0.91, 0.70, 0.34 and 0.45 to the control.