An explanation of abnormal breakage of large particle sizes in laboratory mills

Abstract Abnormal breakage in laboratory mills may be defined as departure from first-order kinetics, and occurs particularly for the larger particle sizes in the mill feed. The reason for this abnormal breakage is that all the particles within a size fraction do not have tire same strength, rather having a distribution of strengths which interacts with a distribution of applied loads on the part of the grinding media. The interrelation between these two distributions, of strengths and forces, is discussed statistically showing the conditions necessary for departure from first-order kinetics. Actual values of the distribution of strengths support the theory, and a final experiment on the grinding of the survival material from previous grinding tests validated the concepts presented.