Kanegafuchi Kagaku Kogyo Kabushiki Kaisha

Minoru Shiga

Toshiji Kano

Yasushi Samejima

Kiyoshi Yamada

Takamichi Kishi

Koji Saiki

Tsutomu Nishio, Deceased

Tsutomu Nishio

A method for removing sulfate ions from an aqueous solution of an alkali metal chloride is disclosed, in which the aqueous solution of the alkali metal chloride containing sulfate ions and zirconium hydrous oxide are brought into contact with each other in a slurry form under acidic conditions to thereby cause the sulfate ions to be adsorbed to the zirconium hydrous oxide by an ion exchange reaction, the zirconium hydrous oxide adsorbing sulfate ions is separated from the aqueous solution and then dispersed in another aqueous liquid to thereby cause it to react with an alkali so as to cause sulfate ions to be desorbed into the aqueous liquid. According to this method, adsorption and desorption take place rapidly and efficiently.

Method for removing sulfate ions from aqueous solution of alkali metal

A method for controlling chlorates in an aqueous alkali metal hydroxide liquor produced by an ion exchange membrane electrolysis is provided, which comprises adding a reducing agent to brine to keep the concentration of chlorates to a specified value or less. The present invention provides an alkali metal hydroxide liquor with low content of chlorates.

Method for controlling chlorates

Disclosed is an electrolysis process which is characterized by carrying out the electrolysis of an aqueous alkali metal halide solution while supplying a cathode liquor into a cathode compartment formed between a cation exchange membrane positioned substantially horizontal and a cathode plate of gas-liquid impermeability, with which the membrane is wetted, then a mixed stream of the cathode liquor and cathode gas being removed from the cathode compartment. Also disclosed is an electrolytic cell which is comprised of an upper anode compartment and a lower cathode compartment partitioned by a cation exchange membrane positioned substantially horizontal, said anode compartment having therein substantially horizontal anodes and an anolyte solution inlet and outlet, and said cathode compartment having a cathode plate with gas-liquid impermeability and a cathode liquor inlet and an outlet of a mixed stream of the cathode liquor and cathode gas.

Electrolysis process and electrolytic cell

Disclosed is an electrolytic process using a horizontal type cation exchange membrane electrolytic cell in which catholyte liquor is supplied into a cathode compartment with initial linear velocity of at least 8 cm/sec and gas content of at most 0.6 at a catholyte liquor outlet. Also disclosed is an electrolytic cell used for the foregoing process. The invention enables not only conversion of a mercury electrolytic cell to a cation exchange membrane electrolytic cell with low cost, but the long-term and stable operation.

Electrolytic process of an aqueous alkali metal halide solution and

Disclosed is a vertical type electrolytic cell partitioned by an ion exchange membrane into an anode compartment and a cathode compartment, the cathode compartment being divided by a non-perforated cathode plate into a cathode gas generation room and a cathode gas separation room. Also disclosed is an electrolytic process using the electrolytic cell wherein the catholyte is circulated between the two rooms as a result of a gas lift effect produced by the cathode gas.

Vertical type electrolytic cell and electrolytic process using the same

An electrolytic process using a horizontal electrolytic cell partitioned by a cation exchange membrane into an anode compartment and a cathode compartment is disclosed which is characterized by supplying into the cathode compartment catholyte liquor at a flow rate satisfying the equation;

Electrolytic process of an aqueous alkali metal halide solution

An electrolytic cell is disclosed comprising an upper anode compartment and a lower cathode compartment partitioned by a cation exchange membrane, in which partitioning spacers are provided on a cathode plate in order to eliminate the troubles owing to non-uniform flow of catholyte liquor, non-uniformity of anode-cathode gap, coarse surface of the cathode plate and the like.

Electrolytic cell with membrane and solid, horizontal cathode plate

Disclosed is a method for preventing a low hydrogen overvoltage cathode from degradation in activity characterized by adding a reducing agent to a cathode compartment of an electrolytic cell which electrolysis an aqueous alkali metal halide solution. According to the invention, no degradation takes place even after repeated shutdown of operation.

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Himeji, Japan

Minoru Shiga