The use of PFC2D to simulate milling
A grinding mill is a rotary device that tumbles media to produce a ground product. Various materials may be used as media, such as steel rods, steel balls or large lumps of the ore (to have an ore-on-ore or autogenous grinding mill). Since this process involves interaction of particles, it lends itself well to DEM simulation. PFC was chosen for this task because of its versatility. The main requirement of the simulation was to create a settled charge of particles inside the mill and rotate the mill for a certain number of revolutions. During the time of mill rotation the energy involved in each contact event had to be calculated by integration and stored for subsequent use by another breakage calculation program, which is outside the scope of this discussion. The tracking of every event generated enormous amounts of data and also required extra inquiry loops that drastically affected the performance of the program. This was further compounded by the required accuracy of the energy integrated, otherwise the breakage predictions would be inaccurate. The paper discusses some of the measures taken to tackle these problems.