Structural Characterization Multi-component SFCA (Silico-Ferrite Calcium Aluminum) Realized in the Actual Sintered Ore

Abstract

The chemical analysis and structural evaluation for the multi-component calcium ferrites were carried out, focusing on the microstructural classifications 1H-ACF, 2H-CF and M-FCF used in the 'Development of environmentally friendly steelmaking process technology (COURSE 50)'. The synthesis was carried out with reference to the multi-component calcium ferrite compositions observed in 1H-ACF, 2H-CF and M-FCF. The crystal structure of 1H-ACF and 2H-CF is strongly influenced by the final temperature reached during sintering. And the crystalline phases observed in 1H-ACF and 2H-CF are SFCA and SFCA-I, with a small amount of SFCA-III. On the other hand, the structure of the SiO₂-rich M-FCF was SFCA. The crystal structure of 2H-CF in "sinter 5" was evaluated by single-crystal X-ray diffraction analysis. The multicomponent calcium ferrites in the 2H-CF region of the actual sintered ores reflect the fact that SFCA, SFCA-I and SFCA-III are of the M_14+6nO_20+8n (M = Si, Fe, Al, Ca, Mg) polysomatic series, and are therefore either SFCA with structural defects or SFCA-I. In the 2H-CF region, SFCA-III, rich in Fe₂O₃ and poor in MgO, was also found and the model structural composition was Ca_6.66Fe_39.43Al_3.28Mg_2.63O₇₂, with the MgO component playing an important role in the formation of spinel sheets. SFCA-III, described in detail for the first time in this report, is richer in Fe₂O₃ than those of SFCA and SFCA-I, suggesting an interesting active role as a new component operating in a more reducing environment with Fe²⁺ present.