A piece of equipment has been devised in which the gap promoting attrition can be varied on a controlled manner with a view to carrying out studies on the relation between attrition in process equipment and in the annular attrition cell.
A modified attrition cell was fitted with fins to simulate flow of particles through a gap and preliminary trials at constant pressure showed that a small gap clearance gave more attrition than a larger one. Constant volume testing yielded a finer product. ProvIsionally, the particle breakage mechanism is unaltered in this type of equipment.
With the cell in its normal format using extruded particles the Gwyn kinetic formulation has been found to be true whatever attrition production size, testing stress and initial particle shape is selected. A shift in breakage mechanism from bodily fracture to surface abrasion has been found at low stresses. In general, mechanisms in operation are flexical bending (for long particles), fracture across a principal dimension, chipping (which is particularly noticeable for angular particles), and surface abrasion.