Predicting granulating behaviour of iron ores based on size distribution and composition

Abstract

Increased demand and diminishing high grade resources have resulted in a large diversity of iron ore sources used in the modern steel mill. Using research on the effect of ore type and size on granulation for single ore blends containing coke, flux and returns, this paper presents a study to model the optimum granulating moisture and related green bed permeability of an iron ore from the size distribution and composition of the ore when added in a simplified sinter blend. The models developed from the granulation test work are applied to a broad range of iron ore types and blends. The effect of particle size on granulation is also quantified across a range of iron ore types. It was found that the optimum moisture could be described accurately by knowing the ore's SiO2, LOIT and Al2O3 (-1 mm) content, as well as the -0.15mm and percentage of Intermediate (0.1 to 1 mm) size fractions. It was also found that for most Iron ores, an increase In particle size close to the 0.1 mm size range has the greatest effect of reducing permeability and increasing granulating moisture. © 2007 ISIJ.