Smelting of Metallic Titanium from an Oxide Flux Using a CaO-Stabilized ZrO₂ Solid-Electrolyte Electrode

Abstract

We propose a smelting reduction process for titanium that uses a flux without any added deoxidizer, such as metallic calcium. For the smelting flux, material from the CaO-Al₂O₃-ZrO₂ ternary system was utilized, and an arbitrary quantity of TiO₂ was added to the ternary flux. The mixed TiO₂-bearing quaternary flux was electrochemically treated in a reaction cell made of CaO-stabilized ZrO₂ solid electrolyte above the melting temperature of titanium. Small, lustrous particles were observed on the crushed flux surface after smelting and quenching, and these were analyzed by optical microscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy (EDX) during scanning electron microscopy, and wavelength-dispersive X-ray fluorescence spectroscopy. The formation of metallic titanium was confirmed by the X-ray diffraction data and elemental mapping by EDX, and was determined to be reasonable from thermodynamic investigations.