Abstract: Provided is a gas diffusion electrode equipped ion exchange membrane electrolyzer including an anode, an ion exchange membrane, and a cathode chamber in which a gas diffusion electrode is disposed, wherein the ion exchange membrane and a cathode chamber inner space in which the gas diffusion electrode is disposed are separated by a liquid retaining member, the outer periphery of the liquid retaining member is held in a void formed in a gasket or a cathode chamber frame constituting the cathode chamber, or the outer periphery and the end face of the outer periphery of the liquid retaining member are sealed, or the outer periphery of the liquid retaining member is joined to and integrated with the gasket.

Abstract: Provided is a gas diffusion electrode equipped ion exchange membrane electrolyzer including an anode, an ion exchange membrane, and a cathode chamber in which a gas diffusion electrode is disposed, wherein the ion exchange membrane and a cathode chamber inner space in which the gas diffusion electrode is disposed are separated by a liquid retaining member, the outer periphery of the liquid retaining member is held in a void formed in a gasket or a cathode chamber frame constituting the cathode chamber, or the outer periphery and the end face of the outer periphery of the liquid retaining member are sealed, or the outer periphery of the liquid retaining member is joined to and integrated with the gasket.

Abstract: [Problems] The liquid pressure of an anode chamber in a two-chamber ion exchange membrane electrolytic cell using a gas diffusion electrode are different among one another depending on depths so that the liquid pressures are applied on an anode or an ion exchange membrane, thereby introducing damage or deformation of the elements. [Means for Solving] A cushion material 10 is accommodated between a cathode gas chamber back plate 9 and a gas diffusion electrode 7 of an ion exchange membrane electrolytic cell 1 such that a repulsive force of the cushion material at the bottom part of the cathode gas chamber is larger than that at the top part. The excessive pressure applied to an ion exchange membrane is suppressed to prevent the generation of scratches or the like by decreasing the repulsive force of the cushion material toward the top in accordance with a differential pressure between an anode chamber pressure and a cathode gas chamber pressure.

Abstract: Provided is a gas diffusion electrode equipped ion exchange membrane electrolyzer including an anode, an ion-exchange membrane, and a cathode chamber in which a gas diffusion electrode is disposed, wherein in a cathode gas chamber formed between a back plate of the cathode chamber and one side of the gas diffusion electrode opposite to the electrolytic surface, a gas-permeable elastic member is disposed between the gas diffusion electrode and the back plate, and the elastic member forms a conductive connection between the gas diffusion electrode and the back plate by making contact with corrosion-resistant conductive layers formed on the surfaces of a plurality of conductive members which are joined to the back plate.

Abstract: The present invention contemplates for providing a producing method which can give highly pure caustic potash in a relatively simple process, in response to the above-described demand for increased high purity in caustic potash. A method to give highly pure caustic potash containing almost no impurities of sodium, chlorine, and heavy metals, such as iron, chromium and nickel, through crystallization, by bringing an aqueous caustic potash solution having a sodium content of 200 mg/kg or less and a chlorine content of 15 mg/kg or less when calculated in terms of a weight of potassium chloride, in which a caustic potash concentration of 48% is to be a standard, into a high temperature state.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alkyl ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: The present invention contemplates for providing a producing method which can give highly pure caustic potash in a relatively simple process, in response to the above-described demand for increased high purity in caustic potash. A method to give highly pure caustic potash containing almost no impurities of sodium, chlorine, and heavy metals, such as iron, chromium and nickel, through crystallization, by bringing an aqueous caustic potash solution having a sodium content of 200 mg/kg or less and a chlorine content of 15 mg/kg or less when calculated in terms of a weight of potassium chloride, in which a caustic potash concentration of 48% is to be a standard, into a high temperature state.

Abstract: [Problems] The liquid pressure of an anode chamber in a two-chamber ion exchange membrane electrolytic cell using a gas diffusion electrode are different among one another depending on depths so that the liquid pressures are applied on an anode or an ion exchange membrane, thereby introducing damage or deformation of the elements. [Means for Solving] A cushion material 10 is accommodated between a cathode gas chamber back plate 9 and a gas diffusion electrode 7 of an ion exchange membrane electrolytic cell 1 such that a repulsive force of the cushion material at the bottom part of the cathode gas chamber is larger than that at the top part. The excessive pressure applied to an ion exchange membrane is suppressed to prevent the generation of scratches or the like by decreasing the repulsive force of the cushion material toward the top in accordance with a differential pressure between an anode chamber pressure and a cathode gas chamber pressure.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alkyl ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alkyl ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alky ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: In order to discharge current from a gas diffusion electrode in an electrolytic unit cell including a gas chamber, the gas diffusion electrode is electrically connected to the wall surface of the gas chamber having conductivity through an electric connecting element in partial contact with the gas diffusion electrode