Abstract: A method for producing sodium hydroxide and/or chlorine by electrolyzing saltwater includes supplying saltwater to an anode chamber of a unit cell in a two-chamber type electrolytic cell, humidifying oxygen-containing gas in a humidifying chamber of the unit cell, and supplying humidified oxygen-containing gas generated in the humidifying chamber to a cathode chamber of the unit cell. The humidifying chamber is adjoined to and in heat exchange relation with the anode chamber or the cathode chamber in the unit cell, or is adjoined to and in heat exchange relation with an anode chamber or a cathode chamber in another unit cell adjacent to the unit cell. The oxygen-containing gas is humidified by generating water vapor with heat from the anode chamber or the cathode chamber adjoined to the humidifying chamber.

Abstract: There is provided a method of production of chlorine.sodium hydroxide capable of being operated stably and economically by preventing calcium from being deposited in an ion exchange membrane. The liquid retention layer 3 having a liquid retention amount per unit volume of the liquid retention layer of 0.10 g-H2O/cm3 or more and 0.80 g-H2O/cm3 or less is put between the ion exchange membrane 12 and the gas diffusion electrode 16. Calcium ions transferred through the ion exchange membrane 12 easily diffuse, thereby making it possible to suppress increase in an electrolytic voltage and drop in current efficiency generated by deposition of the calcium ions inside the ion exchange membrane 12.

Abstract: There is provided a method of production of chlorine.sodium hydroxide capable of being operated stably and economically by preventing calcium from being deposited in an ion exchange membrane. The liquid retention layer 3 having a liquid retention amount per unit volume of the liquid retention layer of 0.10 g-H2O/cm3 or more and 0.80 g-H2O/cm3 or less is put between the ion exchange membrane 12 and the gas diffusion electrode 16. Calcium ions transferred through the ion exchange membrane 12 easily diffuse, thereby making it possible to suppress increase in an electrolytic voltage and drop in current efficiency generated by deposition of the calcium ions inside the ion exchange membrane 12.