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:
May. 01, 2001
Filed:
Sep. 10, 1999
Applicant:
Inventors:
Paul Douglas VerNooy, Media, PA (US);
John Byrne Michel, West Chester, PA (US);
Assignee:
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01F 1/122 ; C01B 7/19 ;
U.S. Cl.
CPC ...
C01F 1/122 ; C01B 7/19 ;
Abstract
A process is disclosed for producing calcium fluoride comprising: (a) mixing aqueous H,PO,with aqueous H,SiF,to form a mixture such that the concentration of H,PO,is at least about 3 moles/liter, (b) adding phosphate rock to the mixture at a rate such that the pH of the mixture is maintained at less than about 1.0 and at a temperature sufficient to form a second mixture containing calcium fluoride, and (c) separating calcium fluoride from the second mixture.