FLUORINE−CONTAINING CATION−EXCHANGE MEMBRANE AND ELECTROYTIC SODA PROCESS

摘要

A cation−exchang membrane comprising at least two layers,a first layer consisting of a fluorine−containing polymer having a sulfonic acid group,and a second layer consisting of a fluorine−containing polymer having a carboxylic acid group on the cathode side thereof,wherein,when conducting an electrolytic soda process using the cation−exchange membrane as a diaphragm between an anode chamber and a cathode chamber,a water permeation amount through the cation−exchange membrane is at least 4.8 mol/F(F:Faraday)under operating conditions that a brine concentration in the anode chamber is 200 g/L,sodium hydroxide concentration in the cathode chamber 32 mass%,current density 5 kA/m2,and temperature 90°C.The electrolysis−use fluorine−containing cation−excahnge membrane gives an excellent effect of keeping a uniform catholyte concentration even when installed in an electrolytic bath without any special circulating means.