Patent ID: 6620340
Filing Date: 2003-09-16
Classification: C23F

Abstract:
A method for making a water carrying pipe corrosion inhibitor which comprises making a solution of zinc orthophosphate, by mixing a zinc metal, an aqueous phosphoric acid, and an oxidizer selected from the group consisting of peroxide, KMnO4, ozone, and mixtures thereof in a stoichiometric amount to facilitate conversion of the zinc metal to divalent zinc, to provide an aqueous phosphate mixture, the zinc metal is present in an amount sufficient to provide a zinc ion concentration of at least about 0.05 weight percent in the solution, the aqueous phosphate mixture being substantially free of sulfate ions, chloride ions and other contaminants, and the aqueous phosphoric acid being present in an amount effective for providing the solution with a pH of less than about 2 so as to provide a phosphate ion concentration of at least about 10 weight percent in the solution.