Abstract: A process produces fine particle titanium dioxide essentially transparent to visible light and essentially UV radiation absorbing. During preparation of the titanium dioxide product, tin dioxide with a particle size of 1 to 10 nm, and preferably 1 to 4 nm, is added, in an amount of 0.5 to 10 weight percent with respect to TiO.sub.2. The particle size of the titanium dioxide is specifically adjusted by the tin dioxide addition. Acicular particles are rounded by heat-treatment between 300.degree. and 800.degree. C., and preferably between 400.degree. and 600.degree. C. The particles can be post-treated to produce a coating of inorganic and/or organic substances. The fine particle titanium dioxide can be prepared by the decomposition of sodium titanate with hydrochloric acid or by suitable hydrolysis of a tetravalent titanium compound which leads to rutile formation.

Abstract: A process is provided for the manufacture of a stable titanyl sulfate solution by diluting a reaction mixture containing iron sulfate and titanyl sulfate with a material selected from water, a titanyl sulfate solution, and mixtures thereof. The titanyl sulfate solution may be recovered or processed to provide titanium dioxide hydrate which may be calcined to provide titanium dioxide pigment.

Abstract: A novel titanium dioxide hydrate is provided whose structure exhibits X-ray diffraction peaks at 24.6.+-.0.4.degree. and 48.+-.0.4.degree., and which is suitable as an adsorbent material. A process for preparing the novel titanium dioxide hydrate also is provided which includes hydrolyzing a specific titanium sulfate solution and thereafter flocculating colloidal titanium dioxide hydrate by the addition of a monobasic acid and recovering the titanium dioxide hydrate.

Abstract: The application is concerned with a process for the manufacture of an aqueous iron (III)-chloride-sulfate solution by the oxidation of iron (II) sulfate with chlorine in aqueous solution.

Abstract: The application is concerned with a process for the manufacture of a titanium dioxide pigment from a titanium sulfate solution by hydrolysis in the presence of nuclei. The latter may be formed externally from any suitable source of titanium sulfate solution and preferably, but not exclusively, from a portion of the titanium sulfate solution used in forming the hydrous TiO.sub.2 ; the nuclei being prepared by mixing the titanium sulfate solution, from whatever source, simultaneously with an alkaline reacting solution and subsequently curing the mixture at elevated temperature. In the present application "titanium sulfate solution" is understood to be a solution which may also contain other substances besides titanium sulfate; and may be obtained, for example, by digestion of titaniferous ores or slags using sulfuric acid, followed by dissolution of the resulting digestion cake.