Influences of Materials Segregation on Feeding Conditions and Performance of HPGR Mill

Abstract HPGR (high-pressure grinding rolls) is widely used as a pre-grinding option in iron ore beneficiation plants. During operation, the wear at the center areas of the rolls is more intense than the edge areas. In this research, the wear pattern on roll surfaces of HPGR in a case study plant was investigated which operates in a close circuit with a wet double-deck vibrating screen. After plant audits, collecting reliable data, and efficient evaluation, it was found that the wear pattern is asymmetric, and the gap between rolls would not be properly adjustable. The reason for the asymmetrical wear was the segregation occurrence in the HPGR feeding chute originating from the non-uniform distribution of HPGR’s feed on the belt conveyor. The results showed that segregation in the feeding bin happens when the bin level is lower than 70%, and it was completely obvious for levels lower than 40%. Also, the non-uniform distribution of HPGR’s feed on the belt conveyor can be decreased by implementing modifications on the connection chute of screen recycle and belt conveyor of HPGR feed.