Particle formation during anatase precipitation of seeded titanyl sulfate solution

The formation of anatase particles in the Sulfate Process is an important step in the production of white pigment. This paper investigates the mechanisms behind particle formation during anatase precipitation from seeded concentrated titanyl sulfate solution. The process of particle formation was found to be highly dependent on the volume of seeds inoculated. Secondary nucleation played an important role in the production of anatase crystals and, ultimately, overall yield of the precipitation step. Anatase crystals were found to be between 4 and 8 nm from powder diffraction line broadening calculations. Nucleation also influences the structure and size of primary agglomerates consisting of a number of crystals. The final anatase particles recovered from the precipitation are in the form of 1-2 mum aggregates, comprised of polycrystalline primary agglomerates.