Article ID: ISIJINT-2025-298
The reduction disintegration index (RDI) of sintered ore, which is the main raw material of blast furnaces, greatly affects blast furnace operation. In order to improve RDI without deteriorating the reducibility index (RI), sintered ore having a CaO concentration of 20 mass%, which is higher than the conventional 10 mass% when using porous Australian iron ore, was produced, and its effects on the mineral structure, porosity, RI and RDI were evaluated.
In the sintered ore having a CaO concentration of 20 mass%, hematite decreased and calcium-ferrite (sum of other component system calcium-ferrite and binary calcium-ferrite), the SFCA-I/SFCA ratio and porosity increased in comparison with that having a CaO concentration of 10 mass%.
When Australian iron ore was used as a raw material for sintered ore, RI increased in sintered ore having a CaO concentration of 20 mass% compared with the one having a CaO concentration of 10 mass%. In addition, RDI was improved in the sintered ore having a CaO concentration of 20 mass% compared with the that having a CaO concentration of 10 mass%. This is due to the formation of binary calcium-ferrite instead of secondary hematite, which deteriorates RDI.
