Comparison of breakage models in DEM in simulating impact on particle beds

Abstract

The discrete element method (DEM) has proven to be a powerful tool to simulate processes involving particulate material. When simulating materials handling operations that lead to mechanical degradation as well as several types of crushers and mills, description of particle breakage inside the DEM environment becomes indispensable, since flow of solids, energy transfer and size reduction are deeply intertwined. However, breakage modeling in DEM is still in an earlier stage of development and comparatively limited work has been carried out demonstrating the validity and limitations of the various models pursued in the literature and already available in commercial DEM packages. The work analyzed particle breakage using three models available in commercial DEM simulation platforms: the bonded-particle model (BPM), the particle replacement model (PRM) and the fast-breakage model (FBM). These were initially calibrated on the basis of the distribution of breakage probabilities of individual 6.3–4.75 mm copper ore particles and, whenever possible, progeny size distributions. Breakage of particles in beds by impact by a falling steel ball is an interesting case for testing breakage models, besides an important microprocess in some comminution operations, since particles interact with each other and with the grinding medium. As such, the potential of the three models to describe size reduction was demonstrated through comparison of unconfined particle bed breakage experiments and simulations. The models demonstrated different abilities to describe the various aspects of breakage. The work then identified opportunities for improvement in each of the models.