Investigation of Particles Breakage and Weakening Behaviors in Multi-Component Feed Grinding by High Pressure Grinding Rolls (HPGR)

Abstract

ABSTRACT One of the main merits of using High Pressure Grinding Rolls (HPGR) is particle weakening, which leads to less energy consumption at downstream grinding processes. Normally, HPGR feed contains various minerals with different weakening behaviors. Therefore, understanding the difference between particle weakening behavior in pure and multi-component feed grinding by HPGR is very important. In the current study, the difference of particle weakening behaviors in pure and mixture feed grinding by HPGR was investigated. To this purpose, the pure and different mixture ratios of magnetite (hard component) and calcite (soft component) minerals were comminuted by HPGR under three different pressures. After grinding, particles breakage behavior was investigated based on the relation of consumed energy and the particle size distribution of products. Particle weakening was studied through measuring changes in fundamental breakage and deformation parameters by Impact Load Cell (ILC). It was concluded that, at pressures resulting in breakage saturation state, the weakening of soft component in mixture feed grinding is more than grinding alone, but the changes in weakening of hard component in the mixture and pure feed grinding are insignificant. It was observed that the weakening of soft component particles in pure feed grinding are 15%, and by increasing hard component to 50 V%, their weakening increases by 19%. It resulted that the presence of hard components led to more energy consumption in soft component breakage and decreased energy dissipation toward particles deformation, leading to an increase of induced damage to soft component particles.