Relationship Between Iron Ore Granulation Mechanisms, Granule Shapes, and Sinter Bed Permeability

The shape and size of granules are the basic factors that influence the packing structure and permeability of granular materials. This paper focuses on granulation mechanisms and the shapes (sphericities) of granules produced during the granulation of different feeds of iron ore for sinter production, using X-ray microtomography. Granule structures revealed that four mechanisms governed the formation of the granules namely autolayering, coalescence, adhesion of micropellets and two-stage layering. The addition of iron ore in the form of concentrate and micropellets to the sinter mixture enhances the mean sphericity of the granules while decreasing the sinter bed voidage and permeability.