| 摘要 |
PURPOSE:To prepare caustic alkali by electrolyzing an alkali chloride by using an electrolytic tank in which a cation exchange membrane is assembled so as to face the rough surface thereof to a cathode side to lower electrolytic voltage remarkably without lowering current efficiency. CONSTITUTION:By using the electrolytic tank which is divided into an anode chamber and a cathode chamber by one cation exchange membrane (e.g.; a fluorine type homogenous cation exchange membrane), an alkal chloride is electrolyzed to prepare a caustic alkali such as NaOH or the like. In this case, at least one side surface of the aforementioned cation exchange membrane is roughened to form a rough surface having 20/mm. or more of recessed parts of which a max. height is 0.05mu or more and roughness is 0.05mu or more. Then, said cation exchange membrane is assembled in the electrolytic tank so as to face said rough surface to the cathode side. That is, by roughening a cathode surface of said homogenous cation exchange membrane appropriately, an amount of H2 gas bubbles adhered to a membrane surface generated from a cathode by electrolysis is remarkably reduced and electrolysis voltage can be lowered. |
