Formation of Titanium Sulfide from Titanium Oxycarbonitride by CS₂ Gas

Previously this group reported that a good quality titanium metal powder can be produced from titanium sulfides by electrochemical OS process. In this study, the sulfurization procedure was examined to synthesize titanium sulfide from titanium oxycarbonitride by CS₂ gas. The experiments were carried out in the temperature range of 1173 K to 1523 K (900 °C to 1250 °C) in a tube reactor with continuously flowing argon (Ar) as carrier gas of CS₂. The formation of titanium sulfide phases from the commercial TiN, TiC, and TiO powders was studied as the initial step. Then, TiO_0.02C_0.13N_0.85 coming from ilmenite was sulfurized to prepare single phase of titanium sulfide. The products were characterized by X-ray diffraction, and the morphology of the sulfides was rigorously investigated, and the sulfur, oxygen, and carbon contents in the products were analyzed. The process was remarkably dependent on the temperature and time. TiN and TiO_0.02C_0.13N_0.85 powders could be fully converted to the single phase of Ti_2.45S₄ (Ti_2+xS₄) at 1473 K (1200 °C) in 3.6 ks. The maximum weight gain of TiN sample was ~ 55.3 pct indicating a full conversion of TiN to Ti₂S₃ phase. The carbon and oxygen contents in this sulfide prepared from the oxycarbonitride were about 1.8 wt pct C and 1.4 wt pct O, respectively. Therefore, the titanium sulfide could be a promising feedstock for the production of commercial grade titanium powder.