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:
Sep. 12, 1978
Filed:
Nov. 10, 1976
Applicant:
Inventors:
Hans-Friedrich Kurandt, Luneberg, DE;
Dietrich Schliephake, Gladbeck, DE;
Assignee:
Veba-Chemie Aktiengesellschaft, Gelsenkirchen-Buer, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01F / ;
U.S. Cl.
CPC ...
423170 ; 423166 ; 423167 ; 423555 ;
Abstract
A process for the purification of phosphate containing impure gypsum to obtain therefrom calcium sulfate semihydrate in a purified form by digesting the phosphate containing gypsum with nitric acid at a temperature between 22.degree. and 100.degree. C, the temperature and nitric acid concentration being regulated such as to dissolve most of the phosphate impurities and to allow the recovery of calcium sulfate semihydrate.