Method for restoring the current efficiency
AssigneeAsahi Glass Company, Limited
InventorsManabu Suhara, Kohji Suzuki, Isamu Takeshita
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Abstract
In the electrolysis of sodium chloride by means of a perfluoro cation exchange membrane for the production of sodium hydroxide having a concentration of from 32 to 40% by weight, a method for restoring the current efficiency, which comprises suspending the electrolysis when the current efficiency of the perfluoro cation exchange membrane has dropped to a predetermined level, and maintaining the catholyte concentration at a level of not higher than 30% by weight.
Claims12
In the electrolysis of sodium chloride by means of a perfluoro cation exchange membrane having carboxylic acid groups as ion exchange groups on the side facing the cathode, for the production of sodium hydroxide having a concentration of from 32 to 40% by weight, a method for restoring the current efficiency of the membrane which has dropped due to a decrease of the electrolytic temperature to a level of at most 80.degree. C. or an increase of the sodium hydroxide concentration to a level of at least 40% during the electrolysis, which comprises suspending the electrolysis when the current efficiency of the perfluoro cation exchange membrane has dropped to a predetermined level, and maintaining the catholyte concentration at a level of not higher than 30% by weight.
Dependencies are inferred from the claim text.