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 (23?15 mm) of sinter from 39?7 to 23?5%. Superior sinter properties were obtained with the 23 mm coke breeze size ,90% in the sinter mix.

For better blast furnace performance, there has always been a need for better quality raw materials like sinter, lump ore, and pellets. Among these raw materials the usage of sinter in blast furnace is at higher side compared to other iron bearing materials. As the quality of sinter product improves, its usage in blast furnaces also increases. Iron ore fines are the main source for sinter making. To improve the sinter properties it is necessary to provide good quality of iron ore fines. Due to depletion of high grade iron ore resources, goethite and limonitic ore content in iron ore fines is expected to increase gradually. Usually limonitic and goethite ore are associated with higher alumina and LOI. The conventional sintering process is one of the well established processes for high quality hematite ore. It does not fully respond to the low grade iron ore associated with goethite and limonite. This has led to deterioration in sinter properties and productivity. In recent years the improvement in the quasi‐particle structure with the granulation process is an effective method for improving sinter quality and productivity. To improve the sinter quality and productivity for low grade iron ore fines, different granulation processes like the conventional one, and other two advanced granulation processes like coke breeze, and flux & coke breeze coating granulation were studied in detail by conducting laboratory pot grate sintering experiments. From the test results it was found that sinter productivity, physical and metallurgical properties of the sinter improved with flux & coke breeze coating granulation process compared to conventional and coke breeze coating granulation process. Proper selection of the granulation time is very important to achieve the desired sinter properties. In the present work detailed laboratory experiments have been carried out by varying the coating time from 30s to 110s to study the influence of flux & coke breeze coating granulation time on mineralogy, productivity, physical, and metallurgical properties of sinter. With a coating granulation time of 50s, higher productivity, higher yield, and stronger sinter (higher T.I) with lower RDI and ‐5mm size sinter were achieved.