The Dynamics of the Ball Mill: Part I: Power Requirements Based on the Ball and Shell System

Abstract

In Part I the relation between the relevant dynamic variables and the power requirements to drive a ball mill, containing the ball charge but without powder charge, has been investigated by means of experiments upon small-scale models. Dimensional analysis is used to obtain the equations in the form of dimensionless groups, and the functional relations between the groups are given analytically, or by means of graphs. This analysis indicates that, so far as power input is concerned, the mill with lifters and the mill without lifters are best treated as separate cases, since the motion of the ball charge is different in the two systems, but that the variation in the number and size of the lifters has little effect upon the power required to drive the mill. By means of the results of this work, the power input required to drive a mill grinding powder may be calculated with reasonable accuracy, and examples of the application of these calculations to large mills are given.