Kureha Kagaku Kogyo Kabushiki Kaisha

Shirou Suzuki

Makoto Fukuda

Teruo Sakagami

Naohiro Murayama

Toshio Enoki

Yoshikazu Kokubu

Kenichi Nakamura

Masakatsu Wagu

The invention relates to cathodic electrodes for use in the electrolytic treatment of alkali halide. The electrode has a substantial mass of copper or copper alloy, and the surface of the mass is roughened and activated by blasting solid and abrasive particles against the mass surface. The roughened surface is then coated with a rhodium or rhodium alloy layer. The effect is a substantial reduction of hydrogen superpotential value.

Cathode for the electrolytic treatment of alkali halide

This invention relates to an apparatus for the electrolytic treatment of alkali halide solution in a three chamber type electrolytic bath assembly comprising an anodic chamber, an intermediate chamber and a cathodic chamber arranged one after another in series. Each chamber is from its neighboring chamber by means of a cationic permselective membrane. The apparatus is characterized, according to this invention, in that the first one of the membranes separating the intermediate and anodic chambers is made of a fluorine-containing resin, while the second membrane separating the intermediate and cathodic chambers includes, as its main ion exchange radial, a pendant type phenolic radical or derivative thereof. The inventive process, which utilizes the above-described apparatus is characterized in that it utilizes a caustic alkali concentration in the intermediate chamber which ranges from about 10-20 wt.% while the output caustic alkali developed at and delivered from the cathodic chamber amounts to a concentration ranging from about 30 to 50 wt.%.

Process for the electrolytic treatment of alkali metal halide solution

This invention relates to an apparatus for the electrolytic treatment of alkali halide solution in a three chamber type electrolytic bath assembly comprising an anodic chamber, an intermediate chamber and a cathodic chamber arranged one after another in series. Each chamber is separated from its neighboring chamber by means of an anodic ion exchange membrane. The apparatus is characterized, according to this invention, in that the first one of the membranes separating the intermediate and anodic chambers is made of a fluorine-containing resin, while the second membrane separating the intermediate and cathodic chambers includes, as its main ion exchange radical, a pendant type phenolic radical or derivative thereof. The inventive process, which utilizes the above-described apparatus characterized in that it utilizes a caustic alkali concentration in the intermediate chamber which ranges from about 10 - 20 wt. % while the output caustic alkali developed at and delivered from the cathodic chamber amounts to a concentration ranging from about 30 to 50 wt. %.

Apparatus and process for the electrolytic treatment of alkali metal

In an electrolytic treatment of alkali halide for the manufacture of alkali hydroxide, a three-chamber type reaction vessel assembly is used so as to provide an anodic chamber, an intermediate chamber and a cathodic chamber arranged in succession one after another and mutually separated by means of anodic (i.e., cationic selective) ion exchange membranes. From the intermediate chamber, low concentration caustic alkali solution is obtained, while from the cathodic chamber, high concentration caustic alkali solution is obtained. In this electrolytic process, the system is operated with the cathodic chamber supplied with no water or aqueous content. The high concentration caustic alkali solution is made from water and alkali metal ions conveyed from the intermediate chamber to the cathodic chamber and exclusively and osmotically passed through the anodic ion exchange membrane. The polymers or copolymers of the anodic ion exhange membrane include sulfonic acid, carboxylic acid and/or phenolic radicals. As the method for the introduction of these radicals, formation of corresponding copolymers may be utilized in the most recommended way. As an example, the membrane may comprise a fluorinated polymer having a cyclic ring structure unit and pendant type sulfonic acid radicals.

Growing community of inventors

Iwaki, Japan

Shirou Suzuki