Effect of 2CaO•SiO2 Addition on Reaction Behavior of Iron Ore Sinters

The effect of 2CaO•SiO2 (C2S) addition on the melt formation temperatures and on the microstructures of iron ore sinters has been elucidated from the perspective of the formation of silico-ferrite of calcium and aluminum (SFCA) in bonding phases as SFCA phases improve the strength of iron ore sinter. The samples used in this study are categorized into two: "C + S" and "C2S". "C + S" samples contain CaO and SiO2 as CaO and SiO2 components, while "C2S" samples contain intermediate compounds of CaO and SiO2, i.e., C2S. Both samples have an identical chemical composition. The mixed raw materials were subjected to differential thermal analysis (DTA) and sintering experiment. DTA reveals that the melt formation temperatures are 1 182°C and 1 216°C for the "C + S" and "C2S" samples, respectively, which are sufficiently lower than the normal sintering temperatures. Sintering experiment reveals that the larger amount of SFCA exist in the "C + S" sample than in the "C2S" sample. This may be associated with the fact that some SiO2 gangue minerals and reagents remain unreacted for the "C + S" sample, causing the CaO/SiO2 ratio of the slag melt to be larger for the "C + S" sample than for the "C2S" sample.