CONTROL OF AN OLYTE-CATHOLYTE CONCENTRATIONS IN MEMBRANE CELLS

1369576 Brine electrolysis DIAMOND SHAMROCK CORP 8 March 1973 [9 March 1972 7 Dec 1972] 11292/73 Heading C7B In the electrolysis of an aqueous NaCl solution to produce Cl 2 and NaOH in a cell having anode and cathode compartments separated byanelectroconductive, hydraulically impervious, cation permselective membrane, an initial NaOH concentration of 31-43% is established in the catholyte and maintained by controlling the average NaCl concentration of the anolyte within the range 120-250 g/l, the sole source of water to the catholyte being that transported through the membrane in the form of hydrated sodium ions. The cathode may be metallic e.g. of Fe; the anode may be of graphite or dimensionally stable e.g. expanded Ti bearing a 2TiO 2 : RuO 2 coating.