Breakage of green iron ore pellets

Abstract

Mechanical degradation of green iron ore pellets prior to induration is a concern and can result in return of material to discs or drums or contamination of the feed to the induration furnace during pelletization. The work investigates the effects of pellet size, drop height, impact angle and type of surface on the response of pellets to multiple impacts, analyzing not only the critical condition for appearance of a surface crack, but also for their disintegration. It also analyzes the effect of deformation velocity during compression, showing that stiffness of green iron ore pellets remains relatively constant while pellet fracture energies significantly increase. It is observed that the effect of pellet size is limited, while the effects of drop height, velocity, angle and type of surface significantly influence degradation of such pellets. Finally, the effect of weakening due to repeated drops on the strength of pellets after firing is demonstrated.