DEM analysis of wear evolution and its effect on the operation of a lab-scale HPGR mill

Abstract

Wear due to compression and abrasion from particles is a critical issue for high pressure grinding rolls (HPGR) mills. Understanding the evolution of wear provides useful insight on its mechanisms and helps to mitigate the issue so mills are operated at their optimal states. This work presented numerical simulations based on the discrete element method (DEM) to analyse the formation and evolution of wear of a lab-scale HPGR mill and to investigate how wear affects mill performance and particle breakage. By coupling the DEM model with the Archard wear model and surface re-meshing, the simulated wear patterns were comparable with those observed in practice, showing a parabolic wear profile wear along the rolls with more severe wear in the centre. In addition, the rear part of the stud, compared with the middle and front parts, experienced more significant wear due to the combined effect of compression and abrasion. While increasing wear had no visible effect on throughput, it reduced mill power draw due to weaker compressive force from the rolls to particles. Furthermore, analysis on particle breakage showed that increasing wear reduced particle breakage and produced coarser products. Increasing wear also caused less damage to particles, suggesting more cycles are required to achieve targeted products.