NEW TECHNOLOGY FOR THE PRODUCTION OF SODIUM HYDROXIDE

CAUSTIC IS PRODUCED IN THE USA TO THE EXTENT OF 36,500T/DAY, MAINLY BY THE ELECTROLYSIS OF BRINE. THE ANODEPRODUCT, CHLORINE, IS UNDER CONSIDERABLE PRESSURE FOR ENVIRONMENTAL REASONS. FOR EXAMPLE, SALES ARE DECLINING TO THE PULP AND PAPER INDUSTRY BECAUSE OF TRACES OF DIOXIN FORMED IN PAPER PRODUCTS. ALSO, OZONE DESTROYING CARBON COMPOUNDS LIKE CHLOROFLUOROCARBONS AND METHYLCHLOROFORM ARE VERY LIKELY TO BE REPLACED BY NON-CHLORINE CONTAINING SUBSTITUTES. AS A RESULT THERE IS CONSIDERABLE INTEREST IN NEW TECHNOLOGIES TO PRODUCE HIGH PURITY CAUSTIC WITHOUT CHLORINE. THE PERFORMANCE OF SOME NOVEL ELECTROLYTIC CELLS FOR THE MANUFACTURE OF SODIUM HYDROXIDE, WITHOUT CO-PRODUCTION OF CHLORINE WILL BE INVESTIGATED IN THE PHASE I RESEARCH WORK. THE CELLS WILL USE MODERN MEMBRANES AND ELECTRODE MATERIALS AND WILL BE DESIGNED TO CONVERT NON-HALOGEN SODIUM SALTS TO HIGH PURITY, AQUEOUS SODIUM HYDROXIDE BY A TECHNOLOGY WHICH IS BOTH HIGHLY ENERGY EFFICIENT AND FRIENDLY TO THE ENVIRONMENT. IT IS ALSO ENVISAGED THAT, LIKE MEMBRANE CHLOR-ALKALI TECHNOLOGY, THE PROCESS SHOULD BE ECONOMICALLY VIABLE OVER A RANGE OF SCALES AND BE PARTICULARLY SUITED TO THE ON-SITE PRODUCTION OF 5 TO 40% SODIUM HYDROXIDE STREAMS FREE OF IMPURITIES SUCH AS CHLORIDE ION.