Influence of pyrrhotite on the corrosive wear of grinding balls in magnetite ore grinding

Abstract

The influence of pyrrhotite on the corrosive wear of grinding balls in magnetite ore grinding was studied using three types of balls, namely, mild steel, high carbon low alloy (HCLA) steel and austenitic stainless steel under different aeration conditions. The results obtained through marked ball grinding tests were correlated with electrochemical measurements using magnetite, pyrrhotite and the respective ball material electrodes. In the absence of sulfide-bearing minerals such as pyrrhotite, corrosive wear of the grinding balls in the wet grinding of magnetite ore was relatively small, even in the presence of oxygen. The presence of pyrrhotite significantly increased the corrosive wear of mild steel and HCLA steel balls, especially in the presence of oxygen. No such increase in ball wear with pyrrhotite addition was observed with austenitic stainless steel balls. Electrochemical studies indicate that the corrosion of both mild steel and HCLA steel in mill water is accelerated in the presence of pyrrhotite.