METHOD OF ELECTROLYZING SODIUM CHLORIDE AQUEOUS SOLUTION

PROBLEM TO BE SOLVED: To provide a method of electrolyzing a sodium chloride aqueous solution which is industrially advantageous by effectively using water used in a process. SOLUTION: The method of electrolyzing the sodium chloride aqueous solution comprising a raw salt dissolving step 10, a filtering step 20, a chelate resin treating step 30, an electrolytic step 40 by an ion exchange membrane system, a dechlorination step 50 and a sodium sulfate removal step 60 is provided with a waste water recovery step 70 for dividing a chelate resin recovery waste water discharged from the chelate resin treating step 30 into a fraction (A) containing hardness components and a fraction (B) substantially containing no hardness component, controlling pH of the fraction (B) substantially containing no hardness component to return to the raw salt dissolving step 10 to use as dissolving water for the raw salt. COPYRIGHT: (C)2009,JPO&INPIT