Ball Mill Grinding Characteristics with Respect to the Chemical Composition of Pyrophyllite

Abstract

The quality and price of pyrophyllite, which is commercially available in the powder form, depends on its particle size. The grinding characteristics of pyrophyllite are affected by its Al₂O₃ content. The breakage of domestic pyrophyllite in a ball mill was evaluated via laboratory grinding tests conducted on a 1.18 × 0.85 mm size fraction. The tests were performed using a 20 (D) × 20 (H) cm laboratory ball mill containing 2.54-cm-diameter alumina balls at a volume filling of 30% with 70% critical speed for various grinding times. The breakage constants were calculated by the inverse method based on the particle size distribution of the ground product. Parameter A of the specific rate of breakage was found to be inversely proportional to the chemical composition of Al₂O₃, and the other breakage constants were similar for all pyrophyllite samples. The simulated and experimental results were in good correlation, and the correlation between A and the Al₂O₃ contents can be expressed by the exponential function 1.3(p.i.)^−0.3.