Continuous grinding in a small wet ball mill Part II. A study of the influence of hold-up weight

Abstract

The effect of changes in the hold-up weight of calcite environment in a small continuous wet ball mill on the grinding behaviour of quartz tracer solids has been studied. The distribution of residence time and rate of breakage for the initial tracer size have been determined experimentally for hold-up weights varying from 1350 to 7640 g and the rates of breakage for sizes below the initial size have been determined by analogue computing techniques. The results show that the dimensionless distribution of residence time tended toward that of a more fully mixed system as the hold-up weight increased and that the first-order breakage rate constants were strongly dependent on the hold-up weight. The product of rate constant and hold-up weight remained approximately constant for each size below 590 μ but for the larger sizes increased considerably with increase in hold-up weight. However, the calcite steady-state product size distributions were only slightly influenced by large changes in the hold-up weight.