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Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling the particle shape. The inter-particle contact parameters were systematically altered whilst the contact parameters between the particle and wall were arbitrarily assumed, in order to purely assess its impact on the angle of repose for the mono-sized iron ore particles. Results show that varying the restitution coefficient over the range considered does not lead to any obvious difference in the angle of repose, but the angle of repose has strong sensitivity to the rolling/static friction coefficient. The impacts of the rolling/static friction coefficient on the angle of repose are interrelated, and increasing the inter-particle rolling/static friction coefficient can evidently increase the angle of repose. However, the impact of the static friction coefficient is more profound than that of the rolling friction coefficient. Finally, a predictive equation is established and a very close agreement between the predicted and simulated angle of repose is attained. This predictive equation can enormously shorten the inter-particle contact parameters calibration time that can help in the implementation of DEM simulations.

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Aiming at addressing the load behavior of iron ore particles in a ball mill, a design of experimental method was used to define a series of discrete element method simulation conditions with two factors being the mill speed and lifter height. The key feature locations of impact toe, bulk toe, shoulder, and head positions were identified visually to determine the load behavior of the charge. To allow the irregular particle shape to be accurately determined, a quick and accurate sphere-clump method was employed in modeling the geometrical model of irregular shape. The results show that the dependence of the impact toe and head on mill speed is higher than its dependence on the lifter height with a correlation of 20.923 and 0.97, respectively. The shoulder changes approximately invariant with the mill speed and varies little with the lifter height. The bulk toe of particles appears to be invariant to the mill speed as well as the lifter height, resulting in the approximately same inclination of the chord joining the shoulder and bulk toe.