Low Temperature Synthesis of Titanium Complex Oxides by a New Synthetic Route of Water-soluble Titanium Complex from Titanium Chloride and Titanium Sulfate as Starting Materials

Abstract

Water-soluble titanium complexes are attractive titanium sources for solution synthesis of titanium-based materials using water as a solvent due to their high stability in aqueous solution in wide range of pH, and have been made from expensive metal titanium ultrafine powder. In this study, TiCl4 and Ti(SO4)2 that are inexpensive reagents than metal titanium fine powder were chosen as starting materials. TiCl4 and Ti(SO4)2 were dropped into distilled water and large amount of NaOH solution was added here, then precipitates of Ti(OH)4 were obtained. Then precipitates were washed with distilled water and dissolved into mixed solution of H2O2 and NH3. And lactic acid as complexing agent was added to the solutions to obtain water-soluble titanium lactate complex solutions. These complex solutions generated no precipitate at pH 0 to 12 for 6 months. Yields of Ti in the both processes were 85 % and removal ratios of Cl- and SO42- ions were 99 and 93 %, respectively. MCO3 (M=Ca2+, Sr2+, Ba2+) were dissolved in the complex solution prepared from TiCl4, and the solution was dried and heated at 873 K for 5 h. Very fine and crystalline particles of CaTiO3, SrTiO3 and BaTiO3 were obtained by heating at 873 K in this solution method, while large particles of CaTiO3, SrTiO3 and BaTiO3 were obtained at 1273 K in solid-state reaction. Low temperature synthesis of titanium complex oxides by a new synthetic route of water-soluble titanium complex from titanium chloride and titanium sulfate as starting materials was successfully achieved.