PROCESS TO PRODUCE TITANIUM DIOXIDE, FINE PARTICULATE TITANIUM DIOXIDE AND AQUEOUS TITANIUM DIOXIDE SUSPENSION

摘要

The titanium dioxide is essentially transparent to visible light and essentially absorbent for UV radiation. In its preparation, finely divided tin dioxide with a particle size of from 1 to 10 nm, preferably from 1 to 4 nm, is employed in an amount from 0.5 to 10 per cent by weight, based on TiO2. The addition of tin dioxide establishes the particle size of the titanium dioxide at the desired value. Conditioning at from 300 to 800 DEG C, preferably from 400 to 600 DEG C, causes rounding of needle-like particles. The particles can be coated with inorganic and/or organic substances by an aftertreatment. Finely divided titanium dioxide can be prepared from sodium titanate by decomposition using hydrochloric acid or by suitable hydrolysis of a compound of tetravalent titanium, which results in rutile formation. The tin dioxide is preferably employed as a colloidal solution formed by reaction of tin tetrachloride with water at a maximum of 22 DEG C.