Effects of Mill Speed on Kinetic Breakage Parameters of Four Different Particulate Pumices

In this study, the effect of mill speed was investigated on different particulate pumice samples at batch grinding conditions based on a kinetic model. For this purpose, S i and B i,j equations were determined from the size distributions at different grinding times, and the model parameters (S i , a T , , , and phi j ) were compared for three different mill speed (fraction of mill critical speed; 65%, 75%, and 85%). The effect of fraction of mill critical speed (phi c) on the grinding for model parameter a T found to be different for four different pumices. Additionally, in this study it was found that optimum grinding occurs at phi c=85% for all pumice samples, in contrast to the 75% of critical speed of the ball mill.