8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

Silico-Ferrite of Calcium and Aluminum (multi-component CF) is one of main minerals in iron ore sinter. Multi-component CF is classified by columnar structure (SFCA) and acicular structure (SFCA-1), which have different crystal structures . It is considered that SFCA-1 has higher reducibility than SFCA, however, the results reported by previous studies have been included factors of adjacent structure such as pores and slag. Moreover, the influence of composition for reducibility has not been clarified while multi-component CF has wide chemical composition. In this study, influence of crystal structure and chemical composition for its own reducibility is investigated on silico-ferrite of calcium and aluminum. Commercial reagents were used to fabricate multi-component CF. Four different chemical composition powder mixtures of SFCA and SFCA-1 were prepared, respectively. These powder mixtures were heated at the range between 1200 and 1400°C, and quenched. Obtained SFCA and SFCA-1 samples were crashed to be powder samples. These powder samples were heated in XRD chamber with heating unit up to 800°C. Atmosphere are N2-CO-CO2 and including two different compositions of H2-H2O system. These atmospheres were changed to simulate blast furnace process. SFCA samples were not reduced until 800°C in CO-CO2, whereas the progress of reduction was shown in CO-CO2-H2-H2O atmosphere. SFCA-1 samples were reduced from 500°C in CO-CO2 atmosphere. The reduction of SFCA and SFCA-1 are enhanced by high H2-H2O composition. Reducibility of SFCA is independent with Fe composition, whereas SFCA-1 is enhanced with increasing Fe composition. SFCA-1 on its reducibility is higher than SFCA. It implied that the valence on Fe is affect to its reducibility.