Effect of the friction coefficient in the discrete element method simulation on media motion in a wet bead mill

In order to provide information on different sample materials to be ground by a bead mill under wet conditions, we have investigated the effect of the friction coefficient in the discrete element method (DEM) simulation on bead motion in the mill. This is also a joint attempt of simulation and experimental works - the former employs the DEM to simulate the bead motion in the mill and the latter is based on the observation of the bead motion in the same mill by a video recorder. Two kinds of sample, gibbsite and limestone, were used for the milling and they were suspended in water at solid concentrations from 2.5 to 10.0 wt%. The bead velocity simulated at different friction coefficients in the DEM was compared with the experimental data and the coefficient classified into two: one is the coefficient between bead and bead, μ