Research on the characteristics of particles size for grinding products with a ball mill at low speed

Abstract

Grinding is a process where the particle size of the material is reduced under the combined effects of the impact action and the abrasion action of steel balls (grinding medium). Even though there are studies related to the grinding process, only a few studies systematically reported the low-speed grinding process. In this paper, the two common minerals: pyrite and quartz are subjected to low-speed grinding using the ball mill technique where the mill rotation is optimized to facilitate the grinding medium to be in the state of cascading. In addition, the relative grindability and grinding kinetic analysis are used to elucidate the particle size distribution characteristics, and rules for achieving the ground product's particle size at low-speed grinding. Further, discussions are made on the grinding characteristics of the mill when the grinding medium is in the cascading motion. The results show that i) finer feed size induces a significant change in the particle size of the ground products; ii) the grinding fineness of pyrite is higher given the same grinding time, whereas the grinding fineness of quartz increases sharply when the grinding time is prolonged; and iii) the grinding processes of the two minerals follow first-order linear kinetic model at low-speed grinding. These findings provide a theoretical foundation to carry out further research on the motion law and grinding characteristics at low- speed grinding.