GRINDING TIME FOR CONTROL OF THE SIZE FRACTION OF PRODUCTS IN THE ATTRITION MILLING

Grinding tests for garnet were carried out by using an attrition mill under wet processes. Effects of feed filling ratios and a chemical age nt (sodium hexametaphosphate, SHP) were investigated on the grinding t ime of the garnet. The progeny particles obtained were screened into v arious particle size intervals, which were 100 mesh over, 100/400 mesh and 400 mesh under. In order to estimate the mass fraction of the par ticles in a given particle size interval, mathematical models were der ived from the first-order reaction model, then compared to experimenta l data. It was observed that variation of the feed filling ratio did n ot show a significant effect on the mass fraction of the product. The chemical agent was, however, effective so that the mass fraction could be controlled by adjusting the content of SHP.