Study on a new molten salt for electrolytic preparation of Ti: dissolution mechanism and kinetic analysis of TiO2 in NaCl-KCl-K2TiF6.

Understanding the dissolution behavior and reaction rate of TiO 2 in the NaCl-KCl-K 2 TiF 6 electrolyte system is paramount for the advancement of a novel titanium metal production process. Initially, the liquidus temperature of the electrolyte system decreases with an increase in K 2 TiF 6 content or the addition of a small amount of TiO 2. Kinetic analysis reveals that the dissolution of TiO 2 in the electrolyte follows a zero-order reaction for the first 30 min, with an activation energy of 2.46 × 105 (J/mol). The saturation concentration of TiO 2 is reached at 300 min, and higher reaction temperatures or increased K 2 TiF 6 content enhance the solubility of TiO 2 in the electrolyte. In addition, the regression equation Y = − 25.02096 + 1.06412 x 1 + 0.0362 x 2 among the solubility of TiO 2 (Y), the ratio of fluoride to chloride in electrolyte (x 1) and experimental temperature (x 2) was established by multivariate regression model. The analysis indicates that TiO 2 dissolves in the electrolyte system as a complex K 2 NaTiOF 5 , releasing TiOF 2 gas during the reaction. Finally, characterization studies on the elemental composition, chemical state, molecular structure, and material morphology of K 2 NaTiOF 5 complex and TiOF 2 gas reveal even distribution of elements. The K 2 NaTiOF 5 complex molecules exhibit irregularly polygonal dispersion, while TiOF 2 exists as agglomerated particles. • Dissolution of TiO 2 follows zero-order reaction in first 30 minutes with Ea of 2.46 × 105 (J/mol). • Saturation concentration of TiO 2 reached at 300 min. • Solubility of TiO 2 increases with higher temperatures and K 2 TiF 6 content. • TiO 2 dissolves as K 2 NaTiOF 5 complex, releasing TiOF 2 gas. • K 2 NaTiOF 5 has cubic crystal system with face-centered lattice structure. [ABSTRACT FROM AUTHOR]