Enhancement Mechanisms of Hydrogen on Metallothermic Reduction of TiO₂ and Anti-oxidation of Titanium Hydride

Titanium is a metal with excellent physical and chemical properties. Although it is highly abundant in the earth's crust, the difficulty of its extraction makes it expensive and restrict its application on a large scale. It has become a world problem to develop a titanium smelting method with low cost and short process. In this research, TiH_1.924 powder with a low oxygen content was produced by hydrogen-assisted magnesiothermic reduction at 650 °C for 2 hours. By optimizing the thermodynamic calculation method of Ti–O–H solid solution, the thermodynamic data of Ti–O, Ti–H, and Ti–O–H with different oxygen contents have been calculated. The results showed that the hydrogen in Ti–O–H has destabilizing effect on the oxygen in Ti–O lattice. Therefore, under hydrogen atmosphere, Mg can break the thermodynamic limit of deoxidation of Ti–O solid solution, obtaining a low oxygen content reduction product. In order to further reduce the oxygen content in the product, the mechanism of secondary oxidation of the titanium hydride product was investigated, leading to the conclusion that higher hydrogen content in titanium hydride can obviously enhance its anti-oxidation property. The research can provide theoretical support for the deep reduction of TiO₂ using low-cost Mg powder to obtain titanium powder with a low oxygen content.