A Quantitative Treatment of Size Reduction in Wet Ball Millings

Abstract

The decrease in geometric mean particle size during wet ball milling follows a reciprocal relationship, which predicts an initial rapid rate of comminution, followed by a slow rate of reduction which develops into a situation where the mean particle size virtually remains constant. The initial rate is directly dependent on the weight of the balls, but the final particle size is an inverse function of ball size. Under these conditions the size distributions follow the Gaudin-Schumann equation. The patterns of behaviour breaks down when the process is limited by the viscosity of the charge, preventing the balls from moving within the mill. This occurs when either the solid to liquid ratio of the charge is high or when the balls are small.