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. 25, 1984
Filed:
May. 11, 1983
Joseph J Scholten, Sittard, NL;
Abraham Van Montfoort, Geleen, NL;
Stamicarbon B.V., Geleen, NL;
Abstract
Process for preparing high mechanical strength pure silicon dioxide suitable for demanding high-grade technical applications including the combination of steps of (a) forming a reaction mixture containing a silicon dioxide precipitate by controllably and gradually admixing with firm agitation an at most 15 weight percent aqueous solution of hexafluorosilicic acid with an about 15 to about 35 weight percent ammonium hydroxide solution at about 25.degree. C. to about 45.degree. C. until the pH is about 8.5 to about 9.2 in the thus formed mixture containing a silicon dioxide precipitate; (b) separating the silicon dioxide precipitate from the mixture; (c) washing the thus separated precipitate; and (d) calcining the thus washed precipitate at about 900.degree. C. to about 1500.degree. C. Silicon dioxide produced in accordance with the present process has better physical properties than commercially available porous alpha-alumina.