Reduction of Titanium Dioxide to Metallic Titanium by Nitridization and Thermal Decomposition

We report a novel process to produce metallic titanium from titanium dioxide—the raw material typically used in the conventional production of titanium metal—via a titanium nitride (TiN) intermediate. TiN is more easily reacted than titanium oxides such as titanium monoxide and titanium dioxide, and shows thermodynamic reactivity equivalent to titanium tetrachloride (TiCl4), which is used industrially as an intermediate in the conventional metallic titanium manufacturing process. The thermal decomposition temperature of TiN (～3500 K), determined from a thermodynamic database, is also significantly lower than those of the oxides (～5300 K) and TiCl4 (～6200 K); thus, it is suitable for use in the available temperature range of an electric arc furnace (～4000 K). Here, we demonstrate the use of TiN as an intermediate for the manufacture of metallic titanium by thermolysis using the arc melting method.