Suppression of corrosion in caustic manufacturing systems
AssigneeOccidental Chemical Corporation
InventorsTilak V. Bommaraju, William V. Hauck, Vernon J. Lloyd
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Abstract
The addition of a small amount of hydrogen or a hydrogen-liberating compound such as a metal hydride to a caustic solution serves to suppress the corrosive effect of the solution on nickel-based surfaces. Typical nickel-based surfaces include caustic evaporator surfaces which contain a caustic solution maintained at a temperature of from about 130.degree. C. to about 180.degree. C. A preferred metal hydride is sodium borohydride which is preferably present in an amount of from about 5 ppm to about 100 ppm. Concentrated caustic solutions containing less than 0.5 ppm of nickel can be prepared by this process.
Claims14
A process for suppressing the corrosion of nickel-based components which contact an aqueous caustic solution in the manufacture of caustic soda comprising adding from about 0.1 ppm to about 500 ppm of metal hydride to said aqueous caustic solution during the caustic manufacturing process.
An aqueous caustic solution comprising from about 10% to about 80% by weight of sodium hydroxide, sodium chlorate as an impurity, and from about 0.1 ppm to about 500 ppm of a metal hydride.
Dependencies are inferred from the claim text.