The use of the discrete element method and fracture mechanics to improve grinding rate prediction

The Discrete Element Method (DEM) is a numerical technique that can simulat e the interaction of discrete particles in dynamic environments such as flu idised beds, jigs, flow in bins, screens and mills. This technique has grea t application potential in comminution modelling at micro-process level. The DEM is being used to determine the grinding rate of ore particles in an Autogenous mill. The frequency of the contact events and the associated en ergy dissipations derived from the simulation are used to determine the par ticle failure rate. The probability of particle failure also depends on the inherent fracture properties of a material; hence fracture tests were cond ucted on an ore sample using a drop-weight impact test machine to obtain a probability fracture model. A second model that uses energy dissipation spectra from the DEM and probab ility fracture model calculations has been proposed. Though the model tends to over-predict breakage generally, there are indications that the model i s responsive to changes in the load behaviour. (C) 2001 Elsevier Science Lt d. All rights reserved.