Nalco Chemical Company

Narasimba M Rao

Donald A Johnson

Walter H Goodman

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.

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Naperville, IL, United States of America

Narasimba M Rao