Abstract: Low-odor, higher molecular weight polyether polyols are produced by purifying the polyether polyols at temperatures of 110.degree. to 150.degree. C. and pressures of 10 to 70 hPa with the addition of 5 to 30% by weight of water, wherein the water is passed in finely divided form, with a droplet diameter of about 5 to 100.mu., through the polyether polyols to be purified for a time of metered addition of 1 to 5 hours.

Abstract: Low-odor, higher molecular weight polyether polyols are produced by purifying the polyether polyols at temperatures of 110.degree. to 150.degree. C. and pressures of 10 to 70 hPa with the addition of 5 to 30% by weight of water, wherein the water is passed in finely divided form, with a droplet diameter of about 5 to 100 .mu., through the polyether polyols to be purified for a time of metered addition of 1 to 5 hours.

Abstract: High-grade titanium dioxide is produced by(a) reacting ilmenite or titanium-containing slag with sulfuric acid,(b) dissolving the material from (a) with water or dilute sulfuric acid,(c) separating insolubles from (b) to obtain a black solution containing titanyl sulfate and foreign metal salts,extracting titanyl sulfate from the black liquor with sulfuric acid and an organic medium containing an organophosphorus compound, separating the foreign metal salts in an aqueous extract phase, recovering titanyl sulfate from the organic extract phase, andhydrolyzing the titanyl sulfate to titanium oxide hydrate.

Abstract: In the production of a solid-free solution of titanyl sulfate by digesting ilmenite or titanium slag with sulfuric acid, and filtering the resulting solid-containing solution of titanyl sulfate to separate the solids, the improvement which comprises filtering the solution under a pressure of about 1 to 16 bars to form a filter cake of a thickness of about 10 to 35 mm. The filter cake is washed with about 0.1 to 0.5 m.sup.3 of water per m.sup.3 of filtrate, the wash water is passed through the filter cake at a flow rate of about 0.1 to 1.2 m/h under a pressure of about 1 to 16 bars, and the filter cake is then squeezed to a solid content of about 50 to 70% by weight.