Recovery of titanium compounds from molten Ti-bearing blast furnace slag under the dynamic oxidation condition

Abstract

A novel technique to recover Titanium compounds from Ti-bearing blast furnace slag under the dynamic oxidation condition was developed and tested. Air was blown into the molten slag as oxygen resource through a lance during the dynamic oxidation process, in which six important results were found: (1) The TiC, (Ti 2O 3), Fe and (FeO) in the slag were oxidized; (2) The temperature of slag temperature rapidly increased; (3) The viscosity of slag decreased; (4) The coalescence, growth and drop of the metallic Fe droplets in the molten slag were carried out under an air agitation condition; (5) The dispersed Ti components were selectively enriched into the perovskite phase, and the perovskite phase could be selectively precipitate and grow; (6) The perovskite phase can be separated by the dressing method, and also these concentrates can be used as the production of the titania enriched material by hydro-metallurgy method. The oxidation of molten slag gives off a large amount of heat, which helps chemical reactions proceed, improve the rate of chemical reactions, and promote the precipitation and growth of the perovskite phase. The features of the technique are clean, low cost and a great capacity to deal with a large quantity of slag. It was confirmed by the experiments of 200 g and pilot experiments of 30 and 1200 kg slag that the precipitation of the perovskite (CaTiO 3) in molten slag is obviously affected by operation factors such as temperature, chemical composition, heat-treatment, additives and so on. The precipitating kinetics and mechanism of the perovskite phase from molten slag during the dynamic oxidation processes were also investigated.