GB1184791A - Improvements in an Electrolytic Process and Apparatus for Liquid Treatment - Google Patents

Abstract

1,184,791. Electrolytic cells. MARSTON EXCELSIOR Ltd. May 31, 1967 [June 15, 1966], No. 26638/66. Heading C7B. Salt solutions are acidified in an electrolytic cell by introducing separate streams of the solution into a catholyte chamber 16 containing a cathode 12 and into an anolyte chamber 17 containing a hydrogen-permeable anode 13 e. g. via inlets 26 and 27, passing D. C. between the cathode and anode to promote ion exchange through an ion-permeable diaphragm 18 between the chambers, supplying hydrogen gas e. g. via inlet 22 and space 23 to the anode interior to be oxadized to hydrogen ions, and removing the resulting acidified salt solution and alkaline salt solution respectively from the chambers 17 and 16 e. g. via outlets 29 and 28. The hydrogen gas is preferably supplied from that liberated at the cathode. The ion-permeable diaphragm may be of glass cloth or asbestos fibre. The cathode may be of graphite, Ti, Ti-clad steel or Cu, stainless steel, Ni or Pt, or a Ta screen holding a dispersion of PTFE with Pt black alone or on carbon; the anode may be of porous Rh, Pd, Ir or Pt, alone or as coating on Ti, Ta or Nb, or porous Ni or graphite. A stack of cells may be used wherein the anolyte and catholyte chambers of each pair of adjacent cells are separated by a bi-polar electrode through which hydrogen liberated at the cathodic face can diffuse to the anodic face. The invention is applicable to the acidification of brines e. g. seawater, and other alkali or alkaline earth metal salts such as sodium sulphate, nitrate or phosphates, particularly used in the production of hypochlorite.