An electrochemical study of corrosive wear of phosphate grinding mill

Abstract

The corrosion of metallic grinding media and mill liner is a very significant problem, particularly under acidic conditions as encountered in the Florida phosphate fertilizer industry. Approximately half of grinding media wear results from corrosion or oxidation dissolution of metal surfaces. An electrochemical cathodic protection process based on impressed current was investigated to reduce wear rates of metals by reducing their electrochemical potentials with excess electrons. The polarization potential and current density required to minimize corrosion were determined using a specially designed ball mill whose electrochemical potential can be controlled. Phosphate grinding tests under controlled electrochemical conditions show that the corrosive wear can be reduced by more than 90% and the overall wear rate by more than 50%. SEM, EDS, and XRD studies were conducted to understand process fundamentals.