DE-Simulation of a vertical stirred ball mill

With the rise of high performance computing systems, new fields of application were open for the industrial use of computer aided simulation systems. Besides other established simulation methods such as the Finite Element Method (FEM), the Discrete Element Method (DEM) with its complex numerical calculation benefits from this high performance. Originally developed by P.A. Cundall, the DEM is a time controlled and contact induced calculation method which is capable of simulating processes with a high number of individual (discrete) particles in a great range of sizes. With this background the actual work deals with the practical use of the DEM in the industrial field of mineral processing. By using a vertical stirred ball mill as a representative example, the simulation capabilities of the DEM should be established on the one hand while on the other, the grinding process should be evaluated by the motion of the grinding media that is caused by the agitator. In order to assess the accuracy of the simulation, the power consumption of the mill is taken as a reference parameter. Since the output of a simulation greatly depends on the material parameters used, they have to be previously determined by extensive material tests. In consideration of the grinding media used (zircon oxide beads), an appropriate measuring strategy has to be developed which combines all necessary testing methods in a reasonable manner. After the power consumption is successfully recreated in simulation, a further simulation series of different stirrer designs should point out potential modification options as well as the DEM’s advantageous visual and numerical methods of analysis.