Assessing Iron Ore Pellet Quality Parameters for Optimized Performance Across Pellet-Based Furnace Operations

The increasing use of iron ore pellets as a substitute for sinter in the blast furnace is a promising strategy to reduce CO2 emission from the steel industry. However, the diverse chemical composition and physical characteristics of commercially available pellets can significantly affect their behavior in the furnace conditions. The current study investigated the effects of key pellet parameters—total iron (T. Fe) content, Al2O3 and MgO content, basicity (B2), porosity and pellet size—on physicochemical properties. Cold compressive strength (CCS), reduction degradation index (RDI), reducibility, and swelling index were evaluated for several pellet brands of inherently different composition. The results indicated that pellet performance cannot be estimated solely on the basis of chemical composition and mechanical strength. Although one pellet brand exhibited superior CCS, it showed inferior reducibility and excessive swelling, highlighting the importance of considering in-furnace behavior during pellet selection. Multiple linear regression (MLR) equations were developed as an exploratory statistical approach to estimate the relative influence of pellet characteristics with the investigated commercial dataset. Within the dataset, favorable performance was generally associated with lower MgO, moderate B2, and porosity near 20%. Additionally, the pellet size was found to play a critical role: larger pellets improved mechanical strength and swelling behavior, while smaller pellets enhanced reducibility and RDI performance. An intermediate pellet size ranging from 9.5 to 12 mm was identified to be optimal. The findings might provide practical guidance for pellet selection and design in high-pellet furnace operations, supporting both operational stability and emission reduction goals. Graphical Abstract