Lanthanothermic Reduction of TiO2

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Process metallurgy and materials processing science, 2020-08, Vol.51 (4), p.1485-1494
• Main Authors: Tanaka, Takara, Ouchi, Takanari, Okabe, Toru H.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Deoxidizing; Lanthanum chlorides; Lanthanum oxides; Materials Science; Metallic Materials; Molten salts; Nanotechnology; Oxygen; Pellets; Smelting; Structural Materials; Surfaces and Interfaces; Thin Films; Titanium; Titanium dioxide
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-020-01860-6

The development of a new titanium (Ti) smelting process is highly desired to decrease the cost of Ti metal. In this study, a new method to produce a low-oxygen-concentration Ti directly from TiO 2 using La as the reductant was developed. First, deoxidation experiments of metallic Ti using La as the deoxidant were conducted, and the ability of La to deoxidize metallic Ti was demonstrated. The oxygen concentrations in Ti were approximately 3900 ± 400 mass ppm O and 120 ± 50 mass ppm O at La/La 2 O 3 and La/LaOCl/LaCl 3 equilibria, respectively, at 1200 K (927 °C). Then, TiO 2 reduction experiments utilizing La as the reductant were conducted to produce low-oxygen-concentration Ti directly. TiO 2 pellets and Ti pieces were held in LaCl 3 molten salt with a sufficient amount of La at 1200 K (927 °C) for 86 ks. After the reaction, the TiO 2 pellets were reduced to metallic Ti without reaction inhibition by the formation of intermediate products. The oxygen concentration of the Ti pieces, which were placed in the molten salt with the TiO 2 pellets, was 100 ± 50 mass ppm O. These results indicate that low-oxygen-concentration Ti containing less than 200 mass ppm O could be produced directly from TiO 2 by utilizing La as the reductant in LaCl 3 molten salt at 1200 K (927 °C). This new method is expected to lead to the development of a new industrial process for the production of ultra-low-oxygen-content Ti from Ti ore without a chlorination process.