Correlation of Grinding Rate with Specific Ball Impact Energy Simulated in Tumbling Mills with Different Pot Lengths

Dry grinding of a gibbsite was conducted using tumbling ball mills with different pot lengths to investigate its effect on the grinding rate determined by the experiment. The ball motion in the mill was simulated by DEM, and the specific impact energy of balls was calculated. The grinding rate increases with an increase in the rotational speed of the mill, and falls rapidly around the critical speed. As the mill length becomes short, the grinding rate becomes large due to the interaction between balls and the side-wall of the pot. All the same, the grinding rate is expressed by a linear function with the specific impact energy regardless of the pot length. Therefore, the grinding rate in tumbling ball milling is predicted by the specific impact energy of balls under any conditions