Correlation between Grinding Results in a Tumbling Ball Mill with Liquid Media and the Analysis of Ball Motions Using DEM Simulation

Ball motions in wet ball milling with a tumbling ball mill were simulated using the discrete element method (DEM). Results of DEM simulation were compared with the results of ball motions and real grinding tests in wet ball milling. In observation of wet ball milling phenomena, ball media slipped in pure water remarkably, but ball motions were clearly activated by the addition of low content of fine particles. In DEM simulation, calculated ball motions were adjusted to observed motions with change of friction coefficient. Then, impact energy of ball media was calculated as a key factor of grinding. Results of grinding tests of wet ball milling were well related to the impact energy. At the grinding tests with various rotation speed, all plots of particle size (d50) of ground product vs cumulative impact energy agreed to just one curve.