Method for the electrolysis of alkali chlorides with oxygen consumption electrodes in a micro-gap arrangement

摘要

Chlor-alkali electrolysis using an electrolytic cell having at least one anode chamber with an anode and an anolyte containing alkali chloride, an ion exchange membrane, and a cathode chamber with an oxygen-consuming electrode as a cathode, comprises: moistening the cathode with an aqueous alkali hydroxide solution containing chloride ion; introducing the anolyte into the anode chamber and an oxygen-containing gas into the cathode chamber; and applying the electrolysis voltage between the anode and cathode. The electrolytic cell is arranged between an ion exchange membrane and the cathode. Chlor-alkali electrolysis using an electrolytic cell having at least one anode chamber with an anode and an anolyte containing alkali chloride, an ion exchange membrane, and a cathode chamber with an oxygen-consuming electrode as a cathode, comprises: moistening the cathode with an aqueous alkali hydroxide solution containing not > 1000 ppm, preferably not > 500 ppm chloride ion; introducing the anolyte into the anode chamber and an oxygen-containing gas into the cathode chamber; and applying the electrolysis voltage between the anode and cathode. The electrolytic cell is arranged in a micro-gap arrangement, preferably at a distance of 0.01-2 mm between the ion exchange membrane and the cathode. The cathode chamber has a silver-containing catalyst and a flat porous element exhibiting a thickness of 0.01-2 mm flowed-through from catholyte between the cathode and membrane.