THE ANALYSIS OF REPEATED BREAKAGE EVENTS AS AN EQUIVALENT RATE-PROCESS

The process of repeated breakage events can be treated similarly to the process of grinding continuously with time by defining an equivalent specific breakage factor by a first-order rate equation w1(N) = w1(O) exp(-k1N), where w1(N)/w1(O) is the fraction of size 1 left unbroken after N events. This concept is illustrated with data on fracture of small cylinders of alumina fired at a target fitted with a force transducer. This showed that there was a distribution of the maximum impact force even at a given velocity, due primarily to different orientations on impact. The distribution at a given velocity could be normalized for all velocities, and the median impact force increased with impact velocity according to Y50-alpha-nu-6/5 as expected. The breakage results could be modelled by assuming a distribution of particle strengths due to different orientations on impact, and the specific breakage factor k1 increased with particle velocity according to k1-alpha-nu-4.35.