Hard/stiff surface coatings for weakening rock particles – Part III: Numerical validation

The size reduction process is an energy-inefficient process for mineral processing, which needs to be remedied. This study uses the Discrete Element Method (DEM) to assess if hard surface coatings on rock particles can weaken them. For that purpose, surface-coated and uncoated particles were generated on the same particle geometry. Then, the impact breakage of both particles was simulated when particles collided with a wall. The simulation results strongly support the hypothesis that strong and/or stiff surface coatings weaken the particles, resulting in higher damage at impact. On the other hand, soft surface coatings are likely to retard the impact breakage of particles. The coated particle that is to be weakened should be relatively strong/stiff so that the generated fragments become finer. High coverage of strong/stiff coatings may be essential if flaky/rectangular particles are to be weakened. There appears to be a limit for the strength/stiffness of the surface coating, above which the particle damage cannot increase further. Introducing a strong or stiff surface coating may even be sufficient to increase particle damage. The simulation results also infer the alternative use of strong and/or stiff surface coatings as grinding aids.