Per: gilvandro bueno (Vale S.a.), Wesley Queiroz Silva (VALE), Suian Andrade Meira (VALE), VINICIUS PERIN PASSIGATTI (VALE), Luis Henrique Torres Dantas (VALE), José Jimmy Penagos (ITV)
Abstract:
In High Pressure Grinding Rolls (HPGR) the particles within a continuous flow of passing ore between the rolls are subjected to high pressures, resulting in their fragmentation and specific surface gains. Its application in grinding iron ore concentrates for pelletizing is associated with increased productivity and pellet quality. In this process, it is common to use roll surfaces composed of studs made of wear-resistant material, Tungsten Carbide (WC). Despite the advancements in this material, wear resistance remains the major challenge in extending the lifespan of the rolls. Analyzing the studs wear mechanism, 8 classes of WC studs were defined for a field test with different percentages of Cobalt (Co) and Nickel (Ni) binders and varying carbide grain sizes. The modified studs were evenly distributed around the roll’s perimeter, with rows of 63 units for each class, being tested over more than 26 thousand hours, approximately 4 years of operation, during which 11.3 million tons of ore were processed. Stud wear was monitored by measuring their height throughout the testing period, totaling ten measurements using a perforated ruler and caliper. The best results at the end of the test showed a wear reduction to less than 0.45 mm/1000 hours of operation or 1.04 mm/ton of processed ore. This corresponds to an increase in stand lifespan of over 25% compared to commonly used studs.