Continuous grinding in a small wet rod mill Part I. Comparison with a small ball mill

Abstract Tests have been done with a small continuous wet rod mill in order to characterise its dynamic behaviour in terms of the type of model previously developed for a small continuous wet ball mill. The three functions studied were the distribution of residence time, the breakage function and the breakage rate as a function of size. Distribution of residence time data showed that flow through the rod mill was similar to that through the ball mill and the contents of the mill were very well mixed. The breakage function results showed that any breakage event statistically produced less fines than in a ball mill. Breakage rate data showed that the coarsest sizes were broken more selectively, thus resulting in less fines in the product than would have been obtained if the breakage had been a result of ball action. Nevertheless it was shown that, overall, breakage in the rod mill could be described in similar terms to breakage in the ball mill, and the models were very similar.