A METHOD FOR SIMULATING THE 3-DIMENSIONAL MOTION OF BALLS UNDER THE PRESENCE OF A POWDER SAMPLE IN A TUMBLING BALL MILL

A method for simulating the motion of balls under the presence of a po wder sample in a tumbling mill is proposed in this paper. The method i s based on the particle element method and a coefficient of friction o f colliding balls is the key to simulate the motion under powder filli ng. Four kinds of samples, i.e. glass beads, silica, aluminum hydroxid e and kaolinite powders, were used for the milling. The movements of b alls with and without a sample were observed visually by a video recor der and compared with the simulation results. The actual movement of b alls in the mill is dependent on the kind of sample and the movement c alculated by the present method can be simulated by choosing a suitabl e coefficient of friction for a given sample. The suitable coefficient of friction for the kaolinite sample is the highest value of all of t he samples and is more than four times larger than that in grinding wi thout sample. Suitable coefficients of friction for the samples are co rrelated with their angles of repose.