Toyo Soda Manufacturing Co., Ltd.

Kosuke Takeshige

Toru Seita

Junji Arika

Hideo Shuyama

Susumo Otsuki

Mitsunobu Kashibe

Michiharu Oogai

A method of producing a cation-exchange membrane having roughed surface which is characterized in mixing silica powder with water to give a suspended or pasty mixture, supporting the resultant mixture on art paper or filter paper, drying the mixture to form silica powder layer, adhering with heating and pressing the silica powder layer on surface of membrane composed of perfluorocarbon polymer, and removing the silica powder layer formed on the surface of said membrane with caustic alkali aqueous solution.

Method of producing cation-exchange membrane having roughed surface

An alkali carbonate containing a fluorine compound is purified by dissolving the crude alkali carbonate in an aqueous solution or suspension of magnesium bicarbonate in order to transfer the fluorine impurity into the resulting colloidal flocculated precipitate whereby the fluorine is substantially separated from the aqueous solution of the alkali carbonate.

Purification of alkali carbonate containing a fluorine compound

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Shinnanyo, Japan

Kosuke Takeshige