Influence of binder dosage on granule structure and packed bed properties in iron ore sintering process

Abstract

This paper investigates the influence of binder dosage on the iron ore sintering process. The granule structure and packed bed properties were explored under a wide range of water and hydrated lime addition levels. At the same moisture content, the addition of more hydrated lime improved the granulation efficiency by forming a more cohesive initial layer on the surface of nuclei particles and producing more agglomeration during granulation. The bed voidage-moisture curve could be divided into three regions, and this curve became flatter with higher hydrated lime addition level. A more mechanistic model of bed voidage [ε = ε0 + (1-ε0) exp(-mR-n), ε0 = 0.36x(eσ)-0.3209] was proposed which represents the influence of cohesive forces and potential for granule deformation by linking voidage to the spread of granule size distribution (σ) as well as the adhering mass ratio (R). For the tested Asia-Pacific region ore blend, adding hydrated lime improved the bed permeability significantly due to the increase in granule size and bed voidage. However, there is a saturation value of solid binder dosage. The improving action becomes limited at 3 wt% since further increase of hydrated lime addition had no further benefit to bed voidage.