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:
Nov. 27, 1990
Filed:
Nov. 09, 1989
Applicant:
Inventors:
Assignee:
Kawatetsu Mining Company, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01B / ;
U.S. Cl.
CPC ...
423339 ; 423338 ;
Abstract
This invention concerns a process for producing high purity silica with less than 5 ppm of impurities from cheap alkali silicate aqueous solution (water glass) for industrial use, which commonly contains more than 2000 ppm of impurities, by directly adding water glass to a mineral acid solution, such as hydrochloric acid, nitric acid, and sulfuric acid so as to dissolve impurities in the mineral acid solution and form silica precipitate, and then rinsing the silica precipitate with a mineral acid solution, provided that the viscosity of the water glass is adjusted to 10-10000 poise in advance of adding to the mineral acid solution.