Alcoa Inc.

Doris Arruda

Kathleen M Tomaswick

A chemical delacquering composition, process and system for delacquering substrates such as aluminum scrap in which an aqueous solution containing at least one short-chain organic acid, preferably a mixture of two short-chain organic acids, and optional components such as surfactants, are contacted onto the substrate(s) with application of heat and agitation. The invention embraces the use of one or more organic acids (carboxylic acids) having a total of 2-12 carbons, preferably 3-8 carbons. Concentration of organic acid by weight ranges from about 0.5-8% per at least one organic acid, or preferably 2-4% for each organic acid component assuming two organic acid components are present. In the preferred embodiment of the invention, about 2-4% each of citric and lactic acids are present in the delacquering composition. Processing temperatures range from 160-212&deg; F., preferably 180-212&deg; F., and most preferably 185-212&deg; F. (higher temperatures may be used in pressurized reactors, although pressurized reactors are not generally necessary).

Chemical delacquering process

A chemical delacquering composition, process and system for delacquering substrates such as aluminum scrap in which an aqueous solution containing at least one short-chain organic acid, preferably a mixture of two short-chain organic acids, and optional components such as surfactants, are contacted onto the substrate(s) with application of heat and agitation. The invention embraces the use of one or more organic acids (carboxylic acids) having a total of 2-12 carbons, preferably 3-8 carbons. Concentration of organic acid by weight ranges from about 0.5-8% per at least one organic acid, or preferably 2-4% for each organic acid component assuming two organic acid components are present. In the preferred embodiment of the invention, about 2-4% each of citric and lactic acids are present in the delacquering composition. Processing temperatures range from 160-212&deg; F., preferably 180-212&deg; F., and most preferably 185-212&deg; F.(higher temperatures may be used in pressurized reactors, although pressurized reactors are not generally necessary).

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Monroeville, PA, United States of America

Doris Arruda