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:
Oct. 06, 1992
Filed:
May. 08, 1990
Nicholas D Spencer, Washington, DC (US);
W. R. Grace & Co.-Conn., New York, NY (US);
Abstract
The invention process provides a metal oxide, or oxides of more than one more metal, wherein the oxides have a mean particle size less than 1 micron. The oxides are made by steps including (1) reacting an aqueous solution of a metal salt (or salts) that form insoluble carbonate(s), thereby to form a carbonate precipitate, followed by (b) recovering the precipitate, e.g., by filtration; (c) redispersing the precipitate in water to form a second very dilute slurry; (d) spray-drying said second slurry; (e) calcining the spray-dried product at a low temperature (e.g., 540.degree. C.), followed by a final calcination in atmosphere consisting of flowing oxygen initially under reduced pressure (e.g., 2 Torr). The spray-dried spheroids comprise particles having a mean particle size less than one micron, a property carried over into the products of both calcinations.