1992 Volume 108 Issue 7 Pages 549-555
The two dimensional motion of the individual balls in a tumbling ball mill was analyzed numerically by a Distinct Element Method using the extended Kelvin model composed of nonlinear spring and nonlinear dashpot. A parameter related to the coefficient of viscosity is determined from the data of imperfect restitution between ball and mill shell. The simulation of the dynamic motion of the individual balls is based on the nonlinear perfect elasticity, nonlinear viscosity and Newton's law of motion. The dynamic motion of balls during milling calculated was compared with the actual three dimensional motion of balls observed in a mill. The effects of ball charge fraction and mill speed on the impact velocity of balls estimated were also discussed.
It can be concluded that the model simulation developed in the present study predicts approximately the actual motion of the balls in a tumbling mill. The motion reproduced from the simulation is strongly influenced by the ball charge fraction and mill speed. The impact frequency of the individual balls and their impact velocities at individual collisions can be estimated by the simulation technique proposed.
