PIGMENT TITANIUM DIOXIDE AND METHOD FOR ITS PRODUCTION Russian patent published in 1997 - IPC

FIELD: production of dyes, plastics and lamellar plates on paper base. SUBSTANCE: pigment comprises particles of titanium dioxide, 0.01-1.00 mass % of cerium oxide being precipitated on it; and dense amorphous silicium dioxide, its quantity being 1-8 mass % of quantity of titanium dioxide. Pigment may be additionally covered by aluminium hydroxide, its quantity being 2-4 mass % of quantity of titanium dioxide. Pigment is prepared by adding of water soluble cerium compound in aqueous slime of rutile titanium dioxide particles, quantity of cerium compound is 0.01-1.00 mass % (as calculated for cerium oxide) of quantity of titanium dioxide. Said cerium compound interacts with acid or with alkali, thus cerium oxide is precipitated. Then water soluble silicate (its quantity being 1-6 mass %) is added together with mineral acid for precipitation of dense amorphous silicium dioxide. The process is carried out at pH being at least 8. Slime is uninterruptedly mixed and temperature is maintained within 60-100 C range during the whole process of precipitation. Aqueous solution of sodium aluminate together with sulfuric acid is additionally added into slime to precipitate aluminium hydroxide. EFFECT: improved strength, improved stability of desired pigment to photochemical decomposition. 16 cl, 1 tbl