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:
Jul. 11, 1989
Filed:
Dec. 23, 1987
Applicant:
Inventor:
Alan Pearson, Murrysville, PA (US);
Assignee:
Aluminum Company of America, Pittsburgh, PA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01F / ;
U.S. Cl.
CPC ...
423625 ; 423628 ; 423135 ; 423127 ; 501153 ; 502415 ;
Abstract
A process for making alpha alumina particles wherein a Bayer process caustic aluminate solution is treated with both alumina hydrate seed material and alpha alumina promoter particles to precipitate alumina hydrate particles. The precipitated particles are separated from the solution and then dried and calcined to produced alpha alumina particles. Addition of promoter particles in the precipitation step lowers the calcination temperture necessary to produce alpha alumina and results in smaller sized crystallites in the product.