Silicic Acids and Phosphates as an Inhibitor of Corrosion in Drinking Water Supply Systems

The composition of corrosion products in drinking water supply systems mostly consists of iron oxides and hydroxides (amorphous Fe(OH)3, ferrihydrite, goethite, lepidocrocite, magnetite, and maghemite) and carbonates (calcite and siderite). The corrosion layer may be divided into characteristic zones by their chemical and mineralogical composition. Silicic acids and phosphates are added as linked molecules (polymers) and isolated molecules (monomers) to inhibit the corrosion of the pipes. Experiments show that dissolved silica and phosphate may significantly reduce the rates of corrosion and precipitation. Further, silicic acids inhibit the formation of lepidocrocite which is a well known mineral for destabilisation of the corrosion layers. not assigned GG: Industrielle Förderung