Production of Fe–Ti alloy from mixed ilmenite and titanium dioxide by direct electrochemical reduction in molten calcium chloride

Abstract

It is important to develop technologies for the production of high-purity metals and alloys for industrial applications. With the aim of addressing the urgent problem of depletion of resources and the commercial challenges associated with the development of new technologies, detailed research on the electrolysis of mixed FeTiO3/TiO2 in a molten CaCl2 electrolyte was conducted to prepare a high-purity, and high-opacity ferrotitanium (Fe–Ti) intermetallic alloy. Mixed solid oxides of FeTiO3 and TiO2 with FeTiO3:TiO2 molar ratios of 2.78:1.00 and 0.58:1.00 were used for the preparation of Fe–Ti intermetallic alloys (required molar ratios: Ti:Fe=1.36:1.00 and 2.72:1.00). A mixed solid oxide of FeTiO3 and TiO2 was reduced electrochemically in a molten CaCl2 electrolyte at 950°C and a constant voltage of 3.0V. The metallic samples formed by the electrochemical reduction were analyzed using X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectroscopy, electron-probe microanalysis, inductively coupled plasma atomic-emission spectroscopy, ion chromatography, and oxygen and carbon analyzers. The mixed oxide pellets were strongly and successfully reduced to a high-purity Fe–Ti intermetallic alloy of β-Ti (FeTi4) and FeTi phases of high-opacity and with small amounts of detected impurities.