Investigating grinding media dynamics inside a vertical stirred mill using the discrete element method: Effect of impeller arm length

Abstract In this work the grinding media motion inside a vertical stirred mill was investigated using the Discrete Element Method (DEM) and the results were qualitatively compared against similar conditions from published literature. Two impeller designs having different arm length were investigated as function of low and high rotational speeds (50 rpm and 250 rpm). A coarse graining (CG) tool was applied for the first time to time average the DEM data of a vertical stirred mill for the generation of continuous fields of grinding media flow properties such as: solid fraction, kinetics and hydrostatic pressure. This allowed the extraction of meaningful information to generate insights on the grinding process as well as the detailed analysis of the grinding media dynamics at different vessel locations.