| 摘要 |
PURPOSE:To lower electrolytic voltage and enhance electric current efficiency by a method wherein, in electrolysis of alkali chloride by using a cation exchange membrane, an exchange membrane of which one surface or both surfaces is roughened is used and assembled in an electrolysis tank so as to face the said roughened surface to a cathode side. CONSTITUTION:In a method for preparing alkali hydroxide by electrolysing alkali chloride in an electrolysis tank divided into an anode chamber and a cathode chamber by a fluorine type homogenous cations exchange membrane (herein, homogeneous does not mean a mixture of an ion exchange resin powder and a binder and means that total is an ion exchange resin), in case of molding a membrane by extrusion so as to form a roughened surface having embossed portions of which depth is above 1mu and density is above 5 per 1mm<2> on one side or both sides of a cation exchange membrane, is used a membrane produced by a method using a molding die having predetermined embossed portions. This membrane is assembled in an electrolysis tank so as to face the roughened surface to a cathode side. Thereby, H2 gas bubbles generated from a cathode by electrolysis are not almost adhered to a cathode surface and current efficiency is enhanced. |
