The Effect of Feed Characteristics on Particles Breakage and Weakening Behavior in High Pressure Grinding Rolls (HPGR)

Abstract

ABSTRACT High Pressure Grinding Rolls (HPGR) is a high-energy efficiency device that has the ability to weaken the particle. This leads to lower energy consumption at subsequent grinding stages. Currently, no commonly used standard indices exist for predicting breakage, and weakening behavior of particles by HPGR. Accordingly, the current study mainly aimed at investigating the relationship between the common grindability/mechanical characteristics of rock (including work index, Brazilian tensile strength, elasticity module, and uniaxial compressive strength) and the breakage and weakening behaviors of HPGR products. For this purpose, six samples (pure calcite, pure magnetite, pure quartz, marmarite rock, travertine rock, and copper ore) with identical particle size distribution were comminuted by HPGR at three pressure force levels of 2.5, 4.5, and 7.5 MPa. Then, the breakage behavior of the samples was evaluated based on the size reduction ratio, followed by studying the weakening of particles by measuring changes in the fundamental breakage and deformation characteristics (mass-specific fracture energy and stiffness) by Impact Load Cell (ILC). The results revealed an excellent relationship between the breakage behavior of particles and their Brazilian tensile strength, as well as their weakening behavior and elasticity module. For particles with a higher module of elasticity (resistivity toward deformation), energy would be consumed for the formation of cracks and subsequently, particle weakening. In the case of particles with a lower module of elasticity, energy is probably dissipated as particle deformation, resulting in more cake formation and less weakening in particles.