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. 14, 1995
Filed:
Dec. 04, 1992
Walter H Goodman, Lisle, IL (US);
Narasimba M Rao, Naperville, IL (US);
Donald A Johnson, Batavia, IL (US);
Nalco Chemical Company, Naperville, IL (US);
Abstract
A method is described for removing ferrometal corrosion products from cooling water systems, which method recycles ferrous/ferric complexing agents and leads to low volume highly concentrated iron wastes for disposal. The method combines, preferably, the use of citric acid or citric acid-tannin complexing agents with erythorbic acid reducing agents to clean corroded surfaces followed by recovery of both complexing and reducing agents for recycle by contacting spent cleaning solution with strong acid cation exchange resins or chelating resins. The resins remove and retain iron species, releasing chelating and reducing agents to resin bed effluents. These are recycled. A concentrated iron waste stream is recovered by regenerating the resin beds with strong acids, preferably HCL, H.sub.2 SO.sub.4, and the like.