Corrosion inhibition by adding alkaline metal gluconates - and zinc salts to the water supply

摘要

The concns. of the zinc salts and the gluconate e.g. sodium gluconate and zinc sulphate are pref. 2-400 ppm and 8-1600 ppm respectively. The combined concn. of the gluconic acid salt and the zinc salt is 10-2000 ppm. An alkaline metal hexametaphosphate (0-400ppm) may also be added as an additional corrosion inhibitor. The gluconate, polyphosphate and the zinc salt have a combined concn. of 10-2000 ppm and the wt. ratio of gluconate to zinc salts is 3:2 - 9:1. Water contg. these form small particles which prevent the oxygen from diffusing across the water-metal interface.