An improved cathode with a conductive metal core and a Raney-type catalytic surface predominantly derived from an adherent .[.NiAl 3 .]. .Iadd.Beta Nickel (NiAl 3 ) .Iaddend.crystalline precursory outer portion of the metal core is disclosed. The precursory outer portion preferably has molybdenum added to give a precursor alloy having the formula Ni x Mo 1-x Al 3 where x is within the range of from about .[.5.]. .Iadd.95 .Iaddend.to about 15 weight percent. Also disclosed is a method of producing a low overvoltage cathode. The method includes the steps of taking a Ni-Mo core or substrate having about 5-20 weight percentage of Mo and coating it with aluminum then heat treating to form a Ni-Mo-Al alloy with mostly .[.NiAl 3 .]. .Iadd.a Beta Nickel .Iaddend.structure and then leaching out the Al to produce a Raney surface.

Raney alloy coated cathode for chlor-alkali cells

Electrolysis apparatus comprises a diaphragm (21) of a solid polymer electrolyte, and an anode electrode structure (22) and a cathode electrode structure (23) located on opposite sides respectively of the diaphragm (21). At least one of the electrode structures (22, 23) intimately contacts the surface of the diaphragm (21) and comprises a gas-permeable electrically conductive substrate (24) and a film-like porous electrode catalyst layer (25) bonded integrally thereto.

Electrolysis apparatus using a diaphragm of a solid polymer electrolyte, and a method for the production of the same

Disclosed is a solid polymer electrolyte electrolytic cell, e.g., for chlorine production, where the electrodes are in compressive contact with and removable from the permionic membrane. For a preferred exemplification the anode is in compressive contact with and removable from the permionic membrane, and the cathode is bonded to the permionic membrane.

Solid polymer electrolyte chlor-alkali process and electrolytic cell

This invention relates to a new and novel brine system for use in electrolyzing salt to chlorine, caustic soda and hydrogen in chlor-alkali cells employing an ion exchange membrane and, more particularly, to the efficient use of brine as the raw material to be electrolyzed in chlor-alkali membrane cells. This invention also relates to a process for the conversion of a diaphragm cell and evaporator plant to one employing membrane type cells while still utilizing the existing brine treatment and caustic evaporation equipment and the resultant plant installations.

Processing of sodium chloride brines for chlor-alkali membrane cells

PURPOSE:To enable to lower bath voltage, in electrolyzing an aqueous alkali chloride solution, by providing a predetermined finely roughened part on the surface of a fluorine-containing ion exchange membrane of a diaphragm so as to contact said roughened part with an electrode. CONSTITUTION:On the surface of a fluorine-containing cation exchange membrane 1 having a sulfonic acid group, a carboxylic acid group or a phosphoric acid group, a finely roughened part of which a depth or a height from the surface thereof is 0.01-50mu in average is formed in a density of 10 -10 /cm . Next, the exchange membrane 1 having said finely roughened part is arranged in an electrolytic tank so as to contact with at least either of an anode 4 and a cathode 5. Subsequently, in this condition wherein electrodes 4, 5 and the exchange membrane 1 are contacted with each other, an aqueous alkali chloride solution is electrolyzed to produce alkali hydroxide chlorine.

Electrolytic tank for ion exchange membrane

Chlorine and caustic alkalies are produced by an electrolytic dissociation of alkali chloride and with the evolution of H gas, by using a combination of (a) a cation exchange diaphragm and (b) a porous metal cathode of low H overpotential which is located next to the diaphragm and the anode. The anode chamber, separated by the diaphragm from the cathode chamber is filled with an aq. soln. contg. 20-27 wt. % NaCl held a temp. 60-90 degrees C, and the cathode chamber is filled with an aq. NaOH soln., the concn. of which is maintained at 25-50 wt. % (20-45 wt. %) NaOH by replacing drained cuastic alkali soln. by water, and held at a temp. 60-90 degrees C. The cell is operated by using a direct current of c.d. 0.54-5.4 Ka/m2 (1.07-4.28 kA/m2) through an anode of stable dimension in the anode chamber, a Raney nickel electrode in the cathode chamber and fed through the soln. via the diaphragm between the anode and cathode, which is composed of a polymer of perfluorsulphonic acid-poly-fluorhydrocarbon. Bubble formation between the electrodes is minimised so that the electrodes with the diaphragm between can be located close to each other. Pollution problems are greatly reduced as no Hg is used in the construction of the cells.

Electrolytic dissociation of sodium chloride - using a raney neckel cathode and a perforated anode with a diaphragm made of a cation exchange material sandwiched between the electrodes

LOW VOLTAGE CHLOR-ALKALI ION EXCHANGE PROCESS FOR THE PRODUCTION OF CHLORINE A new chlor-alkali electrolytic process for the production of chlorine utilizes a combination of a cation exchange membrane and a porous low hydrogen overvoltage cathode in close proximity to the membrane and to the anode to afford low cell voltage over long periods of operation. Useful membranes for the novel process include the perfluorosulfonic acid polyfluorocarbon polymer membranes sold by DuPont under the Nafion trade name, The process produces chlorine at low power consumption by reducing the overall cell voltage, and on the cathode side of the membrane produces caustic which is essentially free of chloride ion. - 1

Macmullin Robert Burns

Papers

Electrolytic dissociation of sodium chloride - using a raney neckel cathode and a perforated anode with a diaphragm made of a cation exchange material sandwiched between the electrodes

Low voltage chlor-alkali ion exchange process for the production of chlorine