The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 10, 1992
Filed:
Oct. 31, 1990
Gerhard Wiederhoft, Krefeld-Traar, DE;
Gunter Lailach, Krefeld, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
In the production of TiO.sub.2 pigments by the steps of digesting titanium-containing raw materials with sulfuric acid, hydrolyzing the titanyl sulfate obtained, separating the waste acid from the hydrolyzate, bleaching the hydrolyzate and calcining the hydrolyzate after addition of rutilizing nuclei and standardizing chemicals to form TiO.sub.2 pigments, and recovering sulfuric acid from the waste acid, the improvement which comprises employing as the rutilizing nuclei nuclei produced from part of the bleached and then washed hydrolyzate, which nuclei are added to the remainder of the bleached and washed hydrolyzate before calcination.