Breakage of sodium benzoate granules under repeated impact conditions

In many industries, handling or processing of relatively fragile particles takes place and predictions are required whether a significant proportion of the particles is damaged. Particles need to show good resistance against static and dynamic loads. The present paper deals with the study of particle resistance to dynamic loads (mainly the attrition behaviour) using a new instrument developed at the Delft University of Technology. The attrition test involves bombarding the particles against a flat target repeatedly, using a crank-slide mechanism. The new equipment generates extremely large number of collisions for each particle, resulting in reproducible generation of damage. The velocity is controlled by changing the frequency and amplitude of oscillation. The particles encounter many collisions on each spot on the particle surface during the test operation. The change in the particle size distribution at different intervals gives a measure of the damage caused to the particles. The damage has been characterised by estimating the specific rate of breakage, which is correlated to the frequency and amplitude of oscillation.