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Abstract

A method for inhibiting corrosion and controlling deposition in an iron containing aqueous medium is disclosed. The method is capable of providing for the formation of a protective passive oxide film on the metallic surfaces in contact with the aqueous medium without resulting in unacceptable iron based deposition or fouling. Surprisingly, the method does not call for the addition of an organic-phosphonic acid compound or derivative to the aqueous medium as would be normally expected due to the known iron dispersing characteristics of these type compounds. The invention comprises maintaining the pH level at 5.5 or above, assuring that a certain minimal calcium or other ion level is maintained, and adding to the system an orthophosphate compound, a water soluble acrylic acid/hydroxyalkylacrylate copolymer, and a topping agent selected from the group consisting of effective water soluble aminocarboxylic acids, lignosulfonates, citric acid, and tannic acid, and water soluble salt forms and mixtures thereof.

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First Claim