Synthesis of micro-FeTi powders by direct electrochemical reduction of ilmenite in CaCl₂-NaCl molten salt

Abstract

Micro-ferrotitanium powders have been prepared by molten salt electrolysis via directly electrochemical reduction of solid ilmenite in eutectic CaCl₂-NaCl melt at 973 K. In the direct electrochemical reduction process, the reduction of FeTiO₃ first gives rise to the formation of Fe and CaTiO₃, which as intermediates will be further deoxidized at the interface of iron metals, solid CaTiO₃ matrix, and electrolyte to directly form ferrotitanium alloy powders in porous structure. Furthering the electrolytic time can promote the dense structure of ilmenite pellet turn to be more porous, indicating pores inside the pellet are sufficient for the diffusion of oxygen ions. Based on the reduction behavior of partially reduced powders in metallic cavity electrode during the cathodic potentiostatic electrolysis, it shows that the slow deoxidization rate is mainly caused by the more and more difficult reduction of CaTiO₃ than that of FeTiO₃.