Prediction of mill liner shape evolution and changing operational performance during the liner life cycle: Case study of a Hicom mill

The prediction of wear and performance change over the life cycle of the consumable liners used to protect grinding mills is an important element of their optimization. Poor wear behaviour can lead to higher replacement costs and production loss during liner replacement. Prediction of wear behaviour using discrete element method (DEM) can provide valuable information about the impact of the design on the life cycle of the liner. Here, the DEM method is extended to predict the evolution of the shape of the liner throughout the life cycle. Using a Hicom 110 nutating mill as a case study, we demonstrate a process for constructing a wear model that is shown to be able to quantitatively predict the spatially varying wear rates over the surface of the liner. The functional dependence of wear rate on micro-mechanical flow quantities is not currently understood; hence, two model variants for each of the normal impact damage and the shear abrasion damage are considered. This model is validated by comparison with the actual erosion depths of a real liner. It is then used in a multi-step DEM simulation to predict the liner evolution and the operational changes in the mill performance over the full life cycle of the liner. For the Hicom mill, it is demonstrated that the wear is entirely dominated by abrasion and that the best measure of this was the shear energy dissipation of wall contacts. It was also to identify that the floor of the mill was constructed of a more abrasion resistance material. The life cycle analysis showed a 20% decline in power draw as the increasing grinding chamber volume and eroding lifters lead to less efficient operation of the mill. Copyright (C) 2009 John Wiley & Sons, Ltd.