Acceleration of breakage rates of anthracite during grinding in a ball mill

The breakage of anthracite in tumbling ball mills exhibits an unusual behavior of acceleration at fine levels of grinding. This phenomenon was discovered by using the selection function and the primary breakage distribution parameters to predict the size distribution of anthracite using the kinetics of grinding approach. The results show that while the predicted and experimental size distributions are in close agreement up to 6 min grinding time, beyond this the predicted values fall behind the experimental in both dry and wet grinding conditions but particularly in dry grinding. Unlike anthracite, bituminous coals show hindered breakage at longer grind times due to extensive agglomeration of fines. This behavior of anthracite is examined in this paper.