Electrochemical extraction of Fe–Ti–Si alloys direct from Ti bearing compound ores

Abstract

This study demonstrated the successful direct electrochemical reduction of Ti bearing compound ores to Fe–Ti–Si alloys by using the solid oxide membrane (SOM) process. This electrochemical process was carried out in molten CaCl2 at 1100°C and 3·5–4·0 V, the pressed cylindrical pellet of Ti bearing compound ores sintered in air at 1150°C for 2 h acted as a cathode, and the carbon saturated liquid metal contained in an yttria stabilised zirconia tube served as an anode. The electrolytic characteristics were investigated and the products obtained from different conditions were characterised by means of scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. It is found that Ti bearing compound ores can be directly electrochemically reduced to Fe–Ti–Si alloys, the titanomagnetite mixed in the compound ores is first deoxidised to the metal Fe, and the pure Fe extends into the centre of the pellet through the metal/oxide/electrolyte three-phase interlines, which may promote the subsequent electrochemical reactions effectively, and lead to the electrodeoxidation process proceed fast. Importantly, it is observed that some metallic impurities in the Ti bearing compound ores, such as the magnesium, calcium and aluminium, are partly or completely removed during the electrolysis.