Influence of coke breeze particle size on quality of sinter

Iron ore sintering is an extremely complex process involving fuel combustion to generate heat and reducing gases like CO. This heat allows physicochemical, solid and solid-liquid reactions to form liquids of complex components as fuel particles are consumed and cooling processes allow the formation of solid mineral phases. At JSW coke breeze from coke ovens is used as solid fuel in sinter. The properties (size) of the solid fuel play a very important role in determining the sinter microstructural properties and sinter quality. The microstructure of the sinter is a basic necessity and also the first step towards establishing the structural property relationship. Microstructural studies have been carried out to understand the effect of coke breeze particle size on sinter microstructure and sinter properties. The present paper is an attempt to understand and correlate the physical and metallurgical properties of sinter with varying size of the coke breeze particle in sinter mix. It was observed that as the proportion of coke breeze below 3 mm in the sinter mix increased from 53.0 to 90.0% the calcium ferrite phase increased, the number of bigger size pores decreased, and thereby decreased the reduction degradation index (-3.15 mm) of sinter from 39.7 to 23.5%. Superior sinter properties were obtained with the -3 mm coke breeze size similar to 90% in the sinter mix.