METHOD OF SURFACE TREATMENT OF TITANIUM DIOXIDE Russian patent published in 2001 - IPC

FIELD: preparation of colorants. SUBSTANCE: titanium dioxide suspension is prepared in desalted water heated to 70-85 C. Liquid to solid phase is (6-8): 1, pH of suspension is adjusted to 7-9 by adding NaOH solution having concentration of 80-100 g/l. Suspension is heated 90 C. 3-5% aluminium oxide solution is added in amount of 3-5% to titanium dioxide and/or 8-12%. Silicon dioxide solution is added in amount of 1.5-3 % to titanium dioxide and/or 9.8-1% ZnO solution is added to titanium dioxide. Treatment is carried out for 1-6 h under stirring. Precipitate is separated by filtration, washed with desalted water heated to 70-85 C, once again filtered and washed. Precipitate is slightly dried directly on filter with compressed air heated to 40-100 C to water content of not higher than 60%. Process efficiency increased and rate of deposition of compounds on titanium dioxide particles becomes higher. EFFECT: more efficient surface treatment method. 1 cl, 3 ex