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SILICATES FOR CORROSION CONTROL IN BUILDING POTABLE WATER SYSTEMS
Citation:
Lytle*, D A. AND M R. Schock*. SILICATES FOR CORROSION CONTROL IN BUILDING POTABLE WATER SYSTEMS. Presented at National Association of Corrosion Engineers Corrosion/2001, Technical Information Exchange 1556x, Supplemental Treatment of Potable Water in Building Systems, Houston, TX, 3/13/2001.
Description:
Silicates have been used to control the corrosion of drinking water distribution system materials. Previous work has shown that they are particularly useful in reducing the release of zinc from galvanized materials in hot water systems. Negatively charged silicate species were reported to adsorb onto positively charged zinc hydroxide solid at the metal surface and was thought to be protective against corrosion. Silicates have also been used to reduce lead and copper levels in drinking water distribution systems. While scientific evidence supporting a scale enhancement mechanism is absent from the literature, silicates are basic in pH and will be beneficial as a pH adjustment chemical. Silicates have also been shown to reduce iron precipitation in the distribution system which is a positive secondary benefit. The objectives of this talk will be to provide an overview of silicate chemistry and the history of silicate usage for corrosion control, and present data from two case studies where silicate was used to reduce lead and copper in drinking water.