Study on the Oxidation Inhibition of Pyrite by 2-Mercaptobenzimidazole in the Presence of Acidithiobacillus ferrooxidans

Acid mine drainage (AMD) is the result of the oxidation of pyrite and other sulfide ores, and the catalytic action of microorganisms accelerates the generation of AMD. In this paper, the interaction between 2-mercaptobenzimidazole (MBI) and pyrite in the presence of Acidithiobacillus ferrooxidans (At. ferrooxidans) was studied. The results of leaching experiments showed that when the dosage of MBI was more than or equal to 6 g/kg, the oxidation of pyrite was obviously inhibited, and the inhibition rate of 9 g/kg MBI was the best, reaching 97.1%. Electrochemical tests show that when the amount of MBI exceeds 16.8 mg, the pyrite surface treated with MBI will show good oxidation corrosion resistance, and the corrosion resistance will be enhanced with the increase in MBI dosage. Subsequently, the influence of MBI on bacterial growth was ruled out by experiments, and the surface of passivated pyrite was observed and characterized. The results showed that MBI could chelate with iron on the surface of pyrite through -C=N and -SH in the molecule, which enhanced the hydrophobicity of pyrite, thus reducing the contact between pyrite and the external environment and effectively inhibiting the oxidation of pyrite.