Enhancement of bio-oxidation of refractory arsenopyritic gold ore by adding pyrolusite in bioleaching system
(1. School of Civil and Environmental Engineering,
University of Science and Technology Beijing, Beijing 100083, China;
2. State Key Laboratory of Biochemical Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China)
University of Science and Technology Beijing, Beijing 100083, China;
2. State Key Laboratory of Biochemical Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China)
Abstract: Pyrolusite was added in the bioleaching process to enhance the bio-oxidation process. Bioleaching tests at different dosages of pyrolusite ore, pH and inoculation amounts of Acidithiobacillus ferrooxidans were studied. The results showed that the time of the bio-oxidation process was decreased obviously and the arsenic leaching rate reached 94.4% after the bioleaching. The bio-oxidation of arsenopyrite and the effective extraction of manganese from pyrolusite were achieved by the bioleaching process. After bioleaching, the leaching rate of gold from the reaction residues reached 95.8% by cyanide leaching. In the bio-oxidation process, pyrolusite increased the redox potential of the solution to accelerate the bioleaching rate. The experiment showed that there were two reaction modes in the bioleaching process.
Key words: arsenopyritic gold ore; pyrolusite; bio-oxidation; Acidithiobacillus ferrooxidans