Precipitation behaviour of Ti enriched phase in Ti bearing slag

Abstract

In the present paper, a high titanium molten (high Ti) slag was employed as an additive to modify the titanium bearing blast furnace (Ti-BF) slag in order to investigate the influence of the addition of high Ti slag on the crystallisation behaviour of the Ti-BF slag. The variation in the Ti enriched phase and the precipitation behaviour of the Ti enriched phase in the Ti bearing slag were studied in this paper. The Ti bearing slag in this paper was composed of different proportions of high Ti slag and Ti-BF slag. A combination of X-ray powder diffraction, scanning electron microscope equipped with energy dispersive X-ray spectroscope and optical microscopy was applied to determine the crystal structure, clarify the chemical composition and observe the morphology of the Ti enriched phase. It was found that the Ti enriched phase transformed from CaTiO₃ to Mg₄Al₂Ti₉O₂₅ with the addition of high Ti slag. When the Ti bearing slag contained 60 wt-% high Ti slags, Mg₄Al₂Ti₉O₂₅ became the only Ti enriched phase, and it could crystallise completely when the slag was held at 1450°C for 25 min. The formation mechanism of Mg₄Al₂Ti₉O₂₅ is also discussed in this paper.