Formation of Metatitanic Acid Particles in Hydrolysis

Metatitanic acid particles are the clusters formed through aggregation and agglomeration of nano-sized anatase crystallites in the hydrolysis process of titanyl sulphate. The uniformity of particle sizes and consistence of compositions of metatitanic acid particles precipitated from hydrolysis of titanyl sulphate solution are important for the morphology of TiO₂ particles and their optical properties. There have been numerous research efforts on the hydrolysis process, but there is little research on the detailed evaluation of the formation and growth of metatitanic acid particles at each important point in the hydrolysis process of titanyl sulphate. Herein, we report a study of the particle sizes and size distributions of metatitanic acid particles in the key points of the hydrolysis process, using the Light Scattering Particle Size Analyzer and Scanning Electron Microscopy. We found that at the point when initial particles appeared from solution, metatitanic acid exist predominately as primary particles and the primary particles continue to grow in size from gray point and are largely free of agglomeration. After secondary boiling, the primary particles disappear and the secondary particles become predominate. This investigation has implications on the optimal control of the uniformity of particle sizes and quality of metatitanic acid particles.