| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing sodium hydroxide reduced in potassium content by which potassium being impurities can simply be removed from a sodium hydroxide aqueous solution of high concentration without taking a great deal of expense, and to provide the sodium hydroxide reduced in potassium content. SOLUTION: The method for producing the sodium hydroxide aqueous solution reduced in potassium concentration comprises: a stage where a sodium hydroxide aqueous solution comprising potassium ions is prepared; a stage where the sodium hydroxide aqueous solution is admixed with the solid or aqueous solution of sodium tetraphenylborate so as to precipitate potassium tetraphenylborate; and a stage where the precipitated potassium tetraphenylborate is separated. Further, the solid-shaped sodium hydroxide is obtained by evaporating moisture in the sodium hydroxide aqueous solution with a reduced potassium content. COPYRIGHT: (C)2011,JPO&INPIT
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