Production of Titanium Powder by Sodiothermic Reduction in CaCl2 Molten Salts

A new sodiothermic reduction process of TiO2 in CaCl2 melt was proposed aimed at fine Ti powder preparation. The chemical analysis and direct potentiometric methods were used to investigate the reaction pathway of sodiothermic reduction in CaCl2 melt. The as-prepared samples were characterized by X-ray diffraction and scanning electron microscopy. It was found that when reductant of Na was added into the CaCl2 melt, Ca2+ was reduced to Ca by Na and Ca dissolved in the CaCl2 melt. The whole melt would have the reducing power with dissolved Ca. Using this melt as a reaction medium, fine and uniform Ti powder with a purity of around 99 mass pct was successfully produced at 1173 K (900 °C). In addition, as the CaCl2 melt could dissolve about 20 mol pct CaO, it was found that the molar ratio of TiO2 and CaCl2 should be 1:20 to eliminate the by-product CaO from the reaction interface within the experimental period to continue the reduction.