Characterization And Mechanism Of External-Seeds Produced By Hydrolysis Of TiCl₄

Titanium dioxide is an inorganic white pigment with excellent optical performance, which is widely used. The major production methods of titanium dioxide are sulfate method and chlorinate method. In China, sulfate method is the mainly method of titanium dioxide production. In the process of sulfate method, the hydrolysis of titanium sulfate plays an important role, the quality of the end product are affected directly by operating conditions of hydrolysis process. Self-generating seeded process and External seed process are widely used on hydrolysis process to control hydrolysis rate as well as size distribution and crystal structure of metatitanic acid. External seed preparation by TiCl4 is widely used by titanium dioxide manufacturing company in foreign.Because of lack of relevant technology, the quality of product is drop behind in China. Therefore, preparation seed by hydrolysis of TiCl4 is systematic studied in this thesis.The effect of conditions in preparation TiCl4 aqueous solution has been studied. Then obtain accurate method to measure contents of hydrochloric acid in TiCl4 aqueous solution.The seed products characterized through SEM, TEM, BET, CPS, XRD, Raman, TG, DSC, DRS, FT-IR to analysisphysical-chemical properties.Factors affected external seed preparation process was systematic investigatedin this thesis. Single factor experiment is established to verify the impact on quality of product, including the concentrations of TiCl4 aqueous solution, temperature of preparation of TiCl4 aqueous solution, ratio of alkali to titanium tetrachloride, concentrations of sodium hydroxide solution, feeding speed, feeding ways, heating rate, maturing temperature, maturing time.The results showed that ratio of alkali to titanium tetrachloride, feeding speed, feeding ways,concentrations of sodium hydroxide solution are significantly affect to particle size and crystalline phase.