Application of DEM Simulation to an Intensive Mixer

Abstract

The discrete element method (DEM) was applied to describe the basic characteristics of particles in an intensive mixer that is expected to grind only the surfaces of particles with a particular agitator and is applied in many industries. Surface grinding experiments using a sample of bauxite particles were also conducted to compare with the simulation. The roles of the pan and agitator were estimated from the DEM simulations and it was revealed that employing only agitator rotation increases the particle mobility in the vertical direction, while employing both pan and agitator rotation increases the mobility in the horizontal direction and stably maintains large mobility in the vertical direction.
We also investigated the correlation between the rates of energy dissipation during interparticle contact calculated from DEM simulation results and the abrasion rate estimated from experimental results. The abrasion rate was estimated from the particle size distribution obtained from the surface grinding experiments using an intensive mixer charged with bauxite particles and a population balance model in which two mechanisms of attrition—abrasion and fracture—are considered. The results show that the abrasion rate decreased with an increase in energy dissipation due to friction, which suggests that the energy dissipation of the friction obtained from the DEM simulation results could be used to estimate the abrasion rate in the surface grinding process.