Patent ID: 7122148

Claim:
A method for inhibiting corrosion of a metallic substance in an aqueous cooling water system containing soluble SiO 2 of greater than 200 mg/L wherein said aqueous system derives water from make-up source water, comprising the steps: a) removing hardness ions from said source water; b) controlling the ionic strength of the aqueous system water such that said aqueous system water possesses a conductivity from approximately 10,000 to 150,000 μmhos; c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 9.0 or greater, and d) cyclically contacting said aqueous system water with said metallic substance, wherein said pH and ionic strength increases the amount of soluble silica in the multimeric form present in said aqueous system water and inhibits corrosion of said metallic substance.