Fundamentals of silico-ferrite of calcium and aluminium (SFCA) iron ore sinter bonding phase formation: Effects of titanium on crystallisation during cooling

Abstract

The effects of Ti on the crystallisation during cooling of complex Ca-rich ferrite iron ore sinter bonding phases SFCA and Fe-rich SFCA was investigated using in situ synchrotron X-ray diffraction. Cooling of a high temperature (T = 1 623 K) assemblage comprising magnetite and melt in synthetic iron ore sinter mixtures showed that increasing the Ti concentration to 1, 3 and 6 mass% TiO2 resulted in the formation of SFCA to be favoured over Fe-rich SFCA. Fe-rich SFCA was not observed to form at all during cooling in the 6 mass% TiO2 mixture. The absence of Fe-rich SFCA in the high-Ti experiment was rationalised on the basis that the SFCA structure likely accommodates more Ti4+ than the Fe-rich SFCA structure, thereby stabilising SFCA relative to Fe-rich SFCA. Observation of Fe-rich SFCA in sinter may be an indicator that the localised Ti concentration within a sinter blend is likely to be low.