Evaluation of the capturing of dry fine particles between grinding media by drop-weight tests

The micro-processes inside comminution machines are decisive for the grinding result and the overall process efficiency. Especially the estimation of the amount of particles which is captured and stressed between colliding grinding media is of great interest in order to model and optimize the mill operation for dry fine grinding processes. This study investigates the capturing of fine dry particles by means of simplified experiments using a drop-weight tester: While an increase of both the powder flowability and the material fineness were shown to enhance the displacement of the particles out of the zone between a static plate and a falling ball, higher impact velocities and larger media sizes increase the particle capturing. Additionally, the capturing becomes more dependent on the above-mentioned parameters for finer feed materials. Finally, an extension of the active-volume-model, originally developed by Schonert, was proposed to describe the impact of those parameters more adequately. (c) 2020 Elsevier B.V. All rights reserved.