LAUSR

Grinding iron ores in conventional ball mills involve a considerably high consumption of metallic media, resulting in high operating costs. In the case of compact itabirites, the high silica content increases such consumption, potentially exceeding the costs associated with electric power consumption in industrial operations. This paper presents research conducted to assess the use of compact itabirite samples obtained from an industrial crushing plant as grinding media to assist conventional ball grinding in the same installation. In this case, the mill charge included both coarse ore fragments and steel balls. Two ore samples were characterized, and bench-scale grinding tests were carried out in laboratory mills 30 and 58 cm in diameter. The results indicated that coarse compact itabirite ore (pebbles) can be used as grinding media. Grinding tests have shown that replacing 25% of the steel balls with pebbles offered promising results. Their use as mixed grinding media results in a relatively minor increase in power consumption and low pebble wear.