Mitigation of pyrite–forged steel galvanic interactions using the sodium molybdate corrosion inhibitor and its impact on pyrite flotation

Galvanic interactions between sulfide minerals and forged steel media during grinding increase media consumption and release dissolved iron species into the slurry, adversely affecting flotation performance. Although replacement with high-chromium media can mitigate this effect, the use of a corrosion inhibitor during grinding to control flotation response has been rarely previously investigated. This study evaluates whether suppressing galvanic corrosion with the corrosion inhibitor during grinding improves subsequent pyrite flotation. The results showed that 1 h contact between pyrite and forged steel media reduced pyrite recovery by flotation from 82% to 25%, due to the substantial difference in corrosion potentials between pyrite and forged steel, which promotes galvanic interactions. In contrast, the addition of sodium molybdate corrosion inhibitor during the contact period significantly reduced corrosion and restored pyrite recovery to 82%. Notably, an inhibitor efficiency of 53% was sufficient to achieve this recovery, indicating that partial corrosion suppression is adequate to maintain flotation performance. These findings demonstrate that controlled mitigation of galvanic corrosion during grinding provides a practical strategy to optimise flotation performance.