Preparation of low-oxygen titanium powder by magnesiothermic reduction of TiO2 assisted by MgCl2-HoCl3 molten salt
(1. Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China;
2. State Key Laboratory of Complex Non-ferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China;
3. National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China;
4. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China)
2. State Key Laboratory of Complex Non-ferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China;
3. National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China;
4. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China)
Abstract: To reduce the production cost of titanium, a new method for direct preparation of low-oxygen titanium powder by the magnesiothermic reduction of TiO2 with the assistance of a MgCl2-HoCl3 molten salt was proposed. Thermodynamic calculations showed that the magnesiothermic reduction of TiO2 was feasible. However, hindrance of the reduction reaction by the reduction by-product of MgO resulted in a considerably high O concentration in the titanium powder. The addition of HoCl3 to the system significantly reduces the activity of MgO to produce low-oxygen titanium powder. Thermochemical deoxidation and reduction experiments were conducted with MgCl2-HoCl3 molten salt in the temperature range of 1023-1273 K. The results showed that titanium powder with oxygen concentration (mass fraction) below 5.00×10-4 can be prepared at the Mg-MgCl2-HoOCl-HoCl3 equilibrium.
Key words: titanium powder; MgCl2-HoCl3 molten salt; TiO2; HoOCl; magnesiothermic reduction