Toagosei Company, Ltd.

Kaneka Corporation

Chlorine Engineers Corp., Ltd.

Asahi Glass Company, Limited

Mitsui Chemicals, Inc.

Tosoh Corporation

Asahi Kasei Chemicals Corporation

Tokuyama Corporation

Daiso Co., Ltd.

Tsugiyoshi Osakabe

Mitsuharu Hamamori

Koji Saiki

Kiyohito Asaumi

Shinji Katayama

Hiroaki Aikawa

Tatsuhito Kimura

Naoya Okada

Kenji Nonomura

Osamu Ichinose

Yukinori Iguchi

Sei Imayoshi

Tsutomu Ohnishi

Tatsurou Yamashita

Takuya Shimura

Mikihito Sugiyama

Daisuke Hirota

Tadayoshi Shirakawa

Apparatus for producing alkali hydroxide and method for operating apparatus for producing alkali hydroxide are provided. A cooling chamber through which a coolant can pass is constructed by placing a separation wall in a cathode chamber on a side opposite to an ion-exchange membrane, and a flow rate adjuster, such as manual valves, which can adjust the supply flow rate of the coolant is placed in each unit cell. The electrolytic temperature of each unit cell is regulated at an optimum operating temperature depending on the current density by adjusting the flow rate of the coolant without individually adjusting the flow rate of salt water supplied to the unit cell or the concentration of the salt water.

Method for operating apparatus for producing alkali hydroxide

[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 materialis accommodated between a cathode gas chamber back plateand a gas diffusion electrodeof an ion exchange membrane electrolytic cellsuch 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.

Ion exchange membrane electrolytic cell

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.

Method for producing high purity caustic potash

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.

Gas diffusion electrode assembly, bonding method for gas diffusion electrodes, and electrolyzer comprising gas diffusion electrodes

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Nagoya, Japan

Tsugiyoshi Osakabe