Abstract: The invention relates to a method for shutting down an electrolysis cell with a membrane and an oxygen-reducing cathode, which comprises, after the electrical power and oxygen supplies have been disconnected, in emptying the oxygen compartment and filling it with demineralized water having a pH≦7 and in keeping this water in the oxygen compartment throughout the shutdown period.

Abstract: Electrolysing an aqueous solution of sodium chloride by means of a cell comprising a cation-exchange membrane which divides the cell into an anode compartment and an cathode compartment in which the said cathode is placed directly against the cation-exchange membrane, the said cathode compartment being supplied with a humidified gas containing oxygen, characterized in that, in order to obtain a concentration by weight of sodium hydroxide between the cation-exchange membrane and the cathode of less than 38.8%, use is made of an aqueous solution of sodium chloride (anolyte) having a concentration by weight of sodium chloride of less than 200 g/l, and in that the water humidifying the gas containing oxygen is in the form of water vapour.

Abstract: A process for the regeneration of plastic diaphragms is described, in which a mineral acid solution is mixed with a suitable corrosion inhibitor, this mixture is temperature controlled at from approximately 0.degree. to 100.degree. C., preferably 40.degree. to 80.degree. C., in particular 50.degree. to 70.degree. C., and passed through the diaphragm for from approximately 0.1 to 84 hours, preferably 1 to 72 hours, in particular 2 to 24 hours.

Abstract: A salt water electrolysis process for electrolyzing an aqueous alkali chloride solution capable of preventing the deterioration of a gas diffusion cathode is disclosed. A cation-exchange membrane having closely disposed to one surface thereof an insoluble metal anode and having closely adhered or mechanically attached to the opposite surface thereof a liquid permeable gas diffusion cathode is disposed in an electrolytic cell, and electrolysis is carried out while supplying salt water to the anode chamber and an oxygen-containing gas containing water as steam or fine water droplets to the cathode chamber, and an alkali hydroxide is obtained from the cathode chamber. The water-containing gas directly reaches the gas diffusion cathode and since the alkali hydroxide and the alkali carbonate formed at the surface of the cathode are dissolved in the water in the gas and removed from the electrolytic cell, deterioration of the gas diffusion cathode can be prevented.

Abstract: There is now disclosed a method of restoring a used article utilized in electrolysis, such as in a chlor-alkali cell. The used article is usually the cell diaphragm, but may be a cell electrode, particularly when it is in assembly with the cell diaphragm. The restoration method involves treating the article, typically in place in the cell, but which may be removed from the cell, by soaking in a treating composition containing most always hydrochloric acid and corrosion inhibitor. The article after treatment may be baked at elevated temperature. When baking is utilized, it can come before soaking. With or without baking, the article may or may not be involved in a wetting step. Where the restoration involves an article utilized in a chlor-alkali cell, the restoration can readily reduce the problem of hydrogen in the chlorine product produced. Such treatment can also lead to reduced cell voltage as well as reduced cell anolyte level.