Microbial solubilization of gangue minerals and their influence on pyrite bio-oxidation

Abstract Pyrite bio-oxidation can improve the gold leaching extent of refractory gold ores, but it can also cause environmental pollution. In this work, common gangue minerals (feldspar, mica, and quartz) were studied to analyze their solubilization under industrial bio-oxidation condition and their effects on pyrite bio-oxidation. The results show that: They all have certain solubilization under bio-oxidation conditions, and the solubilization sequence is in the reduction order of feldspar, mica, quartz. They all inhibit the pyrite bio-oxidation process, and the order of inhibition is mica, quartz, and feldspar. Reasons for the inhibition include ion toxicity, pulp oppresses, passivation, and changes in microbial communities. The results of response surface analysis indicated that the interaction between feldspar and quartz was the most significant, followed by feldspar and mica, while the interaction between mica and quartz was not obvious. When the weight ratio of pyrite, feldspar, mica and quartz is 10:4:5:11, pyrite dissolves the least, while the weight ratio is 5:9:1:15, pyrite dissolves the most easily. The results provide a reference for related research and provide theoretical support and process optimization guidance for environmental protection and industrial bio-oxidation process.