Abstract: Disclosed is a method of preparing a fibrous, alkali metal chloride brine permeable asbestos diaphragm. The diaphragm is prepared by placing a first electrode in a liquid composition containing asbestos fibers and a surfactant. The liquid composition is maintained basic during the process and an electrical potential is maintained between the electrode on which the asbestos is to be deposited and a second electrode.

Abstract: Disclosed is a method of electrolyzing alkali metal chloride brine in an electrolytic cell having an anolyte chamber containing an anode and a catholyte chamber containing a steel cathode, separated from the anolyte chamber by an asbestos diaphragm. Brine is fed to the anode chamber, a voltage is imposed across the cell, chlorine is evolved at the anode, and hydrogen is evolved at the cathode. According to the disclosed method, the hydrogen overvoltage is reduced by feeding an hydroxy carboxylic acid to the electrolytic cell. Additionally, a phosphorous containing compound and a surfactant may be added to the cell to further reduce the hydrogen overvoltage.