Electrolytic synthesis of ferrotitanium powders from ilmenite in CaCl2-NaCl melts at a lower temperature of 700 °C

Abstract

This paper presents a promising way to decrease the working temperature during the electrolysis of solid ilmenite to produce submicron ferrotitanium powders by selecting equimolar CaCl2-NaCl instead of pure CaCl2 as the electrolyte. The results imply that when ilmenite is electrolysed in equimolar CaCl2-NaCl melts at a lower temperature of 700 °C, porous ferrotitanium powders with homogeneous 2.1-μm particles are produced. The particle size is found to increase with the increase in temperature. However, much more energy is consumed at elevated temperatures. Electrolysis using pure NaCl, CaCl2-NaCl in molar ratios of 0.5:1 and 1:1 and pure CaCl2 melts shows the unique influence of CaCl2 on the reduction process. The results demonstrate that ilmenite can only be reduced to Fe and TiO0.997 in pure NaCl electrolyte, but ferrotitanium is successfully produced in porous structures when mixed eutectic CaCl2-NaCl melts are chosen as electrolytes. The production of ferrotitanium is also found to increase with increasing concentration of CaCl2.