Effect of a material-flow model in prediction of particle-size distributions in open- and closed-circuit mills

A size-continuous breakage-kinetics model is postulated and supported with industrial grinding-mill data. It is shown that the kinetics parameters include the effects of possible classification at the mill discharge. The estimated parameters were then used in the kinetics model to simulate the behavior of a grinding mill in open- and closed-circuit operation. While material transport and kinetics are equally important in open-circuit operation, heavy recycle in a closed circuit makes a detailed material-transport model for grinding unnecessary. In effect, the mill can be considered as backmixed. This suggests that more emphasis should be placed on modelling the classifier than the development of detailed material-transport models for the grinding mill.