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. 01, 1998
Filed:
Jul. 30, 1996
Edward M Anderson, Roland, AR (US);
Neal R Dando, Murrysville, PA (US);
Carl H Lawhon, Benton, AR (US);
Merle D McRaven, Benton, AR (US);
Aluminum Company of America, Pittsburgh, PA (US);
Abstract
A novel gelation-resistant alumina and process for producing such a product and aqueous slurries composed thereof are disclosed, including grinding aluminum oxide of .alpha.-Al.sub.2 O.sub.3 in the presence of about 0.5 to 3.0 wt. % water. The grinding preferably is performed in a sealed ball mill. Dual phase alumina particles have an aluminum oxide inner core of .alpha.-Al.sub.2 O.sub.3 and an aluminum oxide hydroxide outer phase of .gamma.-AlOOH on the .alpha.-Al.sub.2 O.sub.3, including to a nominal depth, e.g., by way of example, of about 5 to 100 nanometers on the inner core of .alpha.-Al.sub.2 O.sub.3, and having up to 40% higher surface area than the initial aluminum oxide of .alpha.-Al.sub.2 O.sub.3. The novel gelation-resistant alumina can be dispersed in an aqueous slurry having a solids content of 65 wt. % and higher, and the resulting slurry has significantly extended shelf life.