2001 Volume 42 Issue 11 Pages 2460-2464
Red fluorescent powder containing yttrium (Y) which is one of the rare earth elements (REEs), was milled in air using a small-scale planetary ball mill to investigate the relation between the extraction rate of Y and the impact energy of the balls calculated from computer simulation based on the Discrete Element Method (DEM) under various conditions. Milling improves the extraction yield, and extraction rate increases with an increase in mill rotational speed, whereas the rate is independent of ball diameter. The same trend is observed in the relation between the specific normal impact energy of the balls and rotational speed. The relation between the extraction rate and the specific normal impact energy can be expressed as a straight line, irrespective of the milling conditions, and it is applicable to estimation of the extraction rate using a large-scale planetary ball mill. Therefore, the extraction rate of Y would be estimated by the specific normal impact energy of the balls calculated from the computer simulation.