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. 24, 1990
Filed:
Oct. 27, 1988
Shinko Pantec Company, Limited, Kobe, JP;
Abstract
A method for regenerating a waste liquor containing nitric acid and hydrofluoric acid to recover highly pure nitric and hydrofluoric acids therefrom. The method comprises adding hydrofluoric acid, or an acid mixture of nitric and hydrofluoric acids having a major content of the hydrofluoric acid, to a nitric acid and hydrofluoric acid waste liquor, and subjecting the resulting mixture to dialysis with an ion-exchange electrodialyzer to recover the dialyzed acids. The acid-removed solution is neutralized to cause a precipitate to form and the precipitate is separated. The resultant solution is subjected to an ion-exchange membrane electrodialyzer using a combination of a bipolar membrane, an anion-exchange membrane and a cation-exchange membrane for separation into the acids and the alkali, which are subsequently recovered. The process has a high current efficiency and high recovery rates for acids.