Role of particle microstructure in comminution

Abstract

Microstructure affects significantly all mechanical properties of materials. While the effect of microstructure on the deformation and failure behavior is well known for steels, alloys and ceramics, this is not the case for the breakage behavior of geological materials inside comminution equipment. Taking advantage of the great progress made in recent years in measuring fundamental data that characterize the deformation, primary fracture and fragmentation behavior of single particles, a detailed analysis was carried out in the present study. Experimental work was conducted using both the Dual-Impact Load Cell and the Ultrafast Load Cell on a variety of single- and multiphase materials. Single-phase particles usually exhibited brittle fracture and their fracture energy decreases continuously with an increase in particle size. On the other hand, ores and rocks more often showed a tendency towards accumulation of damage prior to fracture and their primary fracture energy often became independent of size above a particle size of a millimeters or so. It was also shown that breakage of multiphase particles (particularly those that appear to exhibit low intergranular bonding) produced more intense fragmentation than of single-phase mineral particles. This is discussed in light of the deformation and fracture differences that were measured.