DEM modelling of liner evolution and its influence on grinding rate in ball mills

Wear of grinding mill liners and lifters plays a major role in the overall efficiency and economics of mineral processing. Change in the shape of lifters as they wear has a significant influence on grinding efficiency, and the annual cost of maintenance and mill down-time depends on the life of both liners and lifters. The Discrete Element Method (DEM) is a computational method for simulating the dynamics of particle processes. This paper presents an analysis of 3D simulation of a grinding mill carried out using the EDEM software package customised to predict the rate of wear of lifter geometry and to enable progressive updating of worn lifter geometry profiles. A simplified breakage rate model is developed as a tool to correlate liner profile to mill performance.The combination of the prediction of liner profile and grinding rate shows promise to provide a powerful tool for advanced mill liner design – providing a means to balance liner life and mill performance over the life of the liner at the liner design stage.

Research highlights
► DEM used to simulate the dynamics of ball motion in an industrial scale ball mill.
► Energy distributions with progressively worn lifter geometry profiles were simulated.
► A basic wear model based on detailed DEM output data is proposed.
► DEM simulated energy data was utilised to predict breakage rates of fine particles.
► A simplified breakage rate model was developed to correlate liner profile to mill performance.