Recovery of rutile from Ti-Bearing blast furnace slag through phase transformation and super-gravity separation for dielectric material

Abstract

High-purity rutile (TiO2) possessing favorable dielectric properties was sustainably recovered from Ti-bearing blast furnace slag through phase transformation and super-gravity separation in this study. Firstly, the phase transformation behavior of Ti was studied, the favorable conditions for transformation from perovskite to rutile were determined, and the Ti elements were efficiently enriched into rutile in the Ti-bearing blast furnace slag. Subsequently, the condition for solid and liquid phases of rutile and slag in coexistence was acquired by high-temperature CSLM, the rutile was effectively recovered from the Ti-bearing blast furnace slag through super-gravity separation, and its high purity was verified by the results of XRD, SEM-EDS, XRF, EPMA and Raman. Moreover, the rutile ceramic was prepared, and its dielectric properties were investigated, the dielectric constant was up to around 200, and the dielectric loss was as low as 0.0047 at about 900 Hz. The excellent frequency stability, high dielectric constant and low dielectric loss of the rutile recovered from Ti-bearing blast furnace slag reflect its favorable energy storage capability for dielectric material.