Patent ID: 6468470
Filing Date: 2002-10-22
Classification: C23F

Abstract:
The method of inhibiting white rust corrosion of galvanized steel surfaces of recirculating evaporative water cooling systems containing an oxidizing microbiocide comprising the step of adding to the cooling water a water soluble inhibitor composition containing:(a) one or more organophosphorus compounds selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid; aminotris methylenephosphonic acid; 2-phosphonobutane-1,2,4-tricarboxylic acid; 1,2-diaminocyclohexane tetrakis-(methylene-phosphonic acid); 2-methylpentane diamine tetrakis-(methylene-phosphonic acid); phosphono-hydroxyacetic acid, and phosphono carboxylic acid polymer; (b) one or more tannin compounds selected from the group consisting of condensed tannin groups, hydrolyzable tannin groups, tannic acid, and gallic acid; (c) one or more water soluble alkali metal salts selected from the group consisting of alkali metal salts of molybdenum, titanium, tungsten and vanadium; and (d) wherein said inhibitor composition consists essentially of the following formula: IngredientPercent by WeightSodium molybdate, dihydrate6.25%with about 2.5% active Mo2-phosphonobutane-1,2,4-5.00%tricarboxylic acidPhosphono carboxylic5.00%acid polymerTannic acid3.75%Waterbalance.