Dissolution of Calcium Titanate in Calcium Chloride Melt and Its Application to Titanium Electrolysis

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The solubility of calcium titanate in CaCl₂ melt was investigated above 1373 K, and electrodeposition of Ti metal in the melt was attempted. Many pits were formed on the surface of sintered CaTiO₃ compact by the immersion in CaCl₂ melt above 1373 K. The weight of the compact decreased with the increase in the immersion time, and the decrease got faster with the increase in temperature. Cathodic current in cyclic voltammetry increased with the addition of CaTiO₃ powder in the bath, and the increase in the cathodic currents depended on the bath temperature and the added amount of CaTiO₃. From the results by the electrochemical measurement, the solubilities of CaTiO₃ in CaCl₂ melt were estimated about 7 mol% at 1573 K, and less than 1 mol% at 1373 K. Metallic Ti was detected by XRD analysis in the electrodeposit obtained by potentio-static electrolysis in the bath containing CaTiO₃ above 1373 K, but the amount of Ti metal seemed a little. The similar results were obtained in CaCl₂ melt containing Ca₃Ti₂O₇ though the detailed study has not been completed. It was concluded that calcium titanate was soluble in molten CaCl₂ above 1373 K, and that the CaCl₂ bath containing calcium titanate could be applied to Ti electrolysis.