NONELECTROLYTIC PRODUCTION OF CAUSTIC SODA AND HYDROCHLORIC-ACID FROMSODIUM-CHLORIDE

A nonelectrolytic process for the production of sodium hydroxide and h ydrochloric acid from sodium chloride is explored. This environmentall y friendly process, in which production of chlorine and the use of haz ardous mercury are eliminated, is based on the following principle. A thermally stable cation exchanger such as ZSM-5 zeolite in its H-form undergoes a cation-exchange reaction with a sodium chloride solution t o liberate hydrochloric acid, and the resulting NaZSM-5 zeolite underg oes a cation-exchange reaction with a ammonium hydroxide solution to l iberate sodium hydroxide. The ammonium ion-exchanged zeolite is conver ted into its H-form by deammoniation in the temperature range of 400-5 00 degrees C. The liberated ammonia is trapped in water to form ammoni um hydroxide for reuse.