Low-speed comminution machines (circumferential velocity <5 m/s) with shearing, cutting and tearing stresses have proven to be suitable for the comminution of scrap metal and waste of non-brittle behaviour. Although this type of equipment has found a widespread application, the processes taking place during the comminution are known only to a limited extent. Their clarification was the objective of systematic basic research. Thereby, it seas necessary to indicate the influence of essential parameters (position and shape of the stator, axial clearance) regarding the comminution process. (C) 2004 Elsevier B.V. All rights reserved.