Reduced-order polynomial representation of dem-derived impact and shear energy profiles on mill lifters

Abstract

Abstract

Comminution processes in the mineral industry are notoriously energy-intensive, with tumbling mills relying heavily on internal lifters to dictate charge motion, optimize particle breakage, and facilitate energy transfer. As these lifters inevitably degrade during operation, mill performance, throughput, and energy efficiency decline significantly. Therefore, the precise characterization and prediction of mill lifter wear is critical for optimizing grinding efficiency and improving predictive maintenance strategies in mineral processing. In this numerical study, the Discrete Element Method (DEM) framework was employed to simulate the wear mechanisms governing lifter degradation in a tumbling mill. Using impact and shear energy spectra derived from DEM simulations, an energy-equivalent Archard formulation was applied to the cumulative normal and tangential contact-energy fields from one DEM operating condition. The simulated mill, 4000 mm in diameter and 6000 mm in length, operated at 71.4% of critical speed with 24 lifters and a nominal charge filling of 30%. The lifters have geometry as 150 mm height and 60° face angle. To further investigate the spatial wear on the various faces of the lifter, the energy distributions from 24 lifters were mapped into five physically meaningful regions: Leading Face Plate, Leading Face, Top, Trailing Face and Trailing Face Plate. Median impact and shear energies were extracted and reconstructed using cubic polynomials, producing within-case coefficients of determination of