Process for the production of sodium chlorate

Abstract

A process for the production of sodium chlorate comprising electrolyzing an aqueous sodium chloride solution in a diaphragmless sodium chlorate cell, characterized in that an aqueous sodium chloride solution containing, as impurities, calcium, magnesium, barium and the like is contacted with a chelating ion exchange resin to remove the impurities and the resulting saline solution is supplied into a diaphragmless sodium chlorate cell, thereby enabling sodium chlorate to be produced at a stable electrolytic voltage. Further, there is provided a process for the production of sodium chlorate using a combination of a sodium chlorate cell and a cation exchange membrane process type chlorine-alkali cell, characterized in that a weak saline solution taken out of an anode chamber of a cation exchange membrane process type chlorine-alkali cell is supplied with sodium chloride to form an aqueous sodium chloride solution, which is subsequently contacted with a chelating ion exchange resin to remove calcium, magnesium, barium and the like contained as impurities in said solution, and at least part of the resulting purified saline solution is supplied into a sodium chlorate cell, whereby sodium chlorate formed as a by-product in the chlorine-alkali cell can be effectively recovered and the elevation of the electrolytic voltage of the sodium chlorate cell with the lapse of time can be well prevented.