Modeling breakage by impact of fragments of fired iron ore pellets

Abstract

As soon as fired iron ore pellets suffer their first breakage event, fragments are created. During handling from the pelletizing plant to the steelmaker furnace, several stages of handling occur, so that if a well-formed and nearly spherical pellet breaks early in the handling chain, its fragments may also end up undergoing breakage. This is particularly important if one wishes to predict breakage during all handling stages. Unfortunately, no study in the past analyzed breakage of fragments of fired iron ore pellets, which will likely differ in comparison to the nearly spherical pellets owing to the irregular shapes of fragments. This work investigates breakage of fragments of iron ore pellets by impact using a pneumatic gun device, investigating the effect of fragment history and impact velocity on the breakage probability, the generation of fines by surface breakage as well as the fragment size distribution from body breakage. Results show that fragments are more amenable to surface breakage than well-formed pellets and also that their strength increases as fragment sizes reduce.