Breaking characteristics of different materials and their effect on stress intensity and stress number in stirred media mills

The comminution process in stirred media mills is determined mainly by the number of stress events in the grinding chamber and by the intensity acting at these stress events. For a certain stress intensity, a certain relation between the product fineness and the number of stress events exists. Since the product of stress number and stress intensity is a measure for the specific energy, for each stress intensity, a certain relation between product fineness and specific energy also exists. The effect of stress intensity, stress number and specific energy on the product fineness is determined by the breakage characteristic of the material. With respect to the breakage characteristic, two main groups can be distinguished: firstly, deagglomeration and disintegration and secondly, grinding of crystalline materials. Among others, the breakage characteristics determine how strongly the specific energy consumption is affected by the stress intensity. (C) 2002 Elsevier Science B.V. All rights reserved.