Discrete element analysis of the influence of grinding media shape on the grinding process

Abstract

The shape of the media significantly impacts the grinding process, but opacity (the black box issue) limits in-depth analysis of the mechanisms by which media shape affects grinding. This paper employs Discrete Element Method (DEM) simulations and batch grinding tests to systematically study the effects of different shaped grinding media on the grinding process. Based on changes in the motion behavior of particle assemblies, the lifting curves, dropping trajectories, and energy carrying differences of different media are analyzed. It is observed that spheres roll noticeably within the cylinder, while cylinders and hexagonal prisms, due to their increased contact surfaces, achieve higher lifting heights and speeds, and cover a broader range of motion. Additionally, spheres have higher rotational energy than cylinders and hexagonal prisms, but lower kinetic energy. Further analysis through contact models reveals differences in media and energy transfer. Although spheres make fewer contacts with the minerals, the contact energy is significant, overall greater than that of cylinders and hexagonal prisms. The latter make more frequent contact with minerals, resulting in a more uniform distribution of energy. Simulation results are validated through energy tests and analysis of grinding product particle size, and different media’s crushing energy models are constructed based on the JK model. The results indicate that as mineral particle size decreases, the advantages of steel cylpeb and hexagonal prisms gradually become apparent, and they exhibit good predictive performance.