Surface breakage of fired iron ore pellets by impact

Surface breakage or attrition occurs when iron ore pellets are subjected to handling stages in which the stressing level is insufficient to cause their massive fracture. This breakage mechanism has been investigated for five types of industrial iron ore pellets from impacts against a steel target, leading to a model that accounts for the effect of pellet size, impact energy and angle. The model is then validated on the basis of two different tests. First, a tumbling test on a small drum (0.305 m diameter) is used to demonstrate the validity of the model to describe surface breakage by motion of the pellets at comparatively low velocities, such as those that are found during flow in hoppers and silos. The model is also validated on the basis of simulations of a RO-TAP sieve shaker. It is demonstrated that it is able to predict with confidence results from the tests, proving to be a powerful tool when used in combination with simulations using the discrete element method, to predict mechanical degradation due to surface breakage during handling. (C) 2018 Elsevier B.V. All rights reserved.