Hydrochloric Acid Leaching of Calcium Vapor Reduction Products of TiO₂

Abstract

Preparation of titanium powders from TiO 2 by calcium vapor reduction is one of the most active new methods for titanium production, and the acid leaching process of reduction products plays an important role in this process. In this paper, the leaching process of the reduction products for 1kg scale experiment was investigated by XRF, XRD, SEM-EDS, ICP-AES and EDTA complex formation titration. The results show CaO and other impurities can be effectively removed by dilute HCl solution. The leaching rate of titanium decreases with deceasing temperature, initial acid-to-calcium molar ratio and particle size but increasing liquid-to-solid ratio. And the leaching rate of calcium increases with increasing temperature, initial acid-to-calcium molar ratio, liquid-to-solid ratio but decreasing particle size. Residual oxygen in titanium powders is mainly resulted from uncompleted reduction of the intermediate CaTiO 3 besides the Ti-O solid solution.