Selective Precipitation and Concentrating of Perovskite Crystals from Titanium-Bearing Slag Melt in Supergravity Field

Abstract

Selective precipitation and concentrating of perovskite crystals from titanium-bearing slag melt in the supergravity field was investigated in this study. Since perovskite was the first precipitated phase from the slag melt during the cooling process, and a greater precipitation quantity and larger crystal sizes of perovskite were obtained at 1593 K to 1563 K (1320 °C to 1290 °C), concentrating of perovskite crystals from the slag melt was carried out at this temperature range in the supergravity field, at which the perovskite transforms into solid particles while the other minerals remain in the liquid melt. The layered structures appeared significantly in the sample obtained by supergravity treatment, and all the perovskite crystals moved along the supergravity direction and concentrated as the perovskite-rich phase in the bottom area, whereas the molten slag concentrated in the upper area along the opposite direction, in which it was impossible to find any perovskite crystals. With the gravity coefficient of G = 750, the mass fraction of TiO2 in the perovskite-rich phase was up to 34.65 wt pct, whereas that of the slag phase was decreased to 12.23 wt pct, and the recovery ratio of Ti in the perovskite-rich phase was up to 75.28 pct. On this basis, an amplification experimental centrifugal apparatus was exploited and the continuous experiment with larger scale was further carried out, the results confirming that selective precipitation and concentrating of perovskite crystals from the titanium-bearing slag melt by supergravity was a feasible method.