THE EVALUATION OF A 3-DIMENSIONAL SHAPE FACTOR FOR THE QUANTITATIVE ASSESSMENT OF THE SPHERICITY AND SURFACE-ROUGHNESS OF PELLETS

A three-dimensional shape factor for the characterisation of the quali ty of pellets has been developed based on image analysis. The shape fa ctor includes the separate assessment of deviations from the spherical shape and the presence of surface roughness. These two components can be viewed and compared with the overall three-dimensional shape facto r e(c3), which connects the two features. The shape factor e(c3) has b een applied to three sets of pellets prepared by extrusion/spheronisat ion, and a comparison with the Heywood shape factors has been undertak en. The results demonstrate the ability of e(c3) to differentiate vari ous batches of pellets based on a defined mathematics, whereas the Hey wood shape factors require certain assumptions about the particle outl ine to be applicable.