The Division of Metallurgy of IPT has been working for some years in studies of grinding media wear. Tests have been conducted using phosphate and iron ores, as well as quartz sand, representing the range of abrasivity usually found in practical applications.The pilot plant scale testing program was carried out testing balls made of steel and of different types of high chromium white cast irons, evaluating the wear rates and analyzing the wear micromechanisms of these balls. In that work, the objective was the validation of the wear evaluation method, comparing the results obtained in an industrial ball mill, grinding phosphate ore with those obtained running continuously the pilot-scale laboratory mill. Quantitative correlations between the perfomance of the grinding media in the industrial and the laboratory ball mills were obtained. The present work had for objective the characterization of the grinding media for evaluation of balls acquired from different suppliers. The main stages were: Determination of the polarization curves (evaluation of the preferential corrosion's effect), Metallographic characterization (chemical and metallographic characterization of the balls samples) and Wear tests (to evaluate the wear of the grinding media in a continuous milling and classification pilot scale plant). The results obtained allowed to elaborate a ball wear rate ranking. The final result is a validated testing method available for the industry to foresee the wear of grinding media for each type of ore, making possible the selection of suppliers as well as the development of the best alloy for each case, aiming to lower costs in the grinding process.
comminution; grinding media; wear
