Particle abrasion at high solids concentration in stirred vessels - II

Abstract In the first paper, it was shown that the fragments detached from particles undergoing abrasion in stirred vessels were of approximately constant size independent of the time over which abrasion had been occurring. This paper reports data from an experiment conducted to test the accuracy and the effec of the constant fragment size approximation. It is shown to be reasonable if size and size distributions are determined on a number basis (as they were in the previous work) but it is unsatisfactory if an area or volume basis is used. In the latter two cases, the mean size decreases with time. By considering the underlying theory of particle-particle impact and abrasion, it is shown that a different basis should be used for different aspects of the determination of E, the “energy” required to produce a unit area of fragment surface. When this is done, it is found that E is independent of time though the mass abrasion rate is greatest initially when the particle asperities are being removed. The experimental technique and model offer a convenient means of assessing the abrasion resistance of brittle materials in stirred vessels and of selecting suitable operating conditions to enhance or reduce abrasion.