Novel electrolysis cell

• US 4,343,690 A
• Filed: 12/11/1979
• Issued: 08/10/1982
• Est. Priority Date: 08/03/1979
• Status: Expired due to Term

• Current Assignee: De Nora Permelec S.p.A. (Industrie De Nora S.p.A)
• Original Assignee: Oronzio de NORA Impianti Elettrochimici SPA (Industrie De Nora S.p.A)
• Inventors: de Nora, Oronzio
• Primary Examiner(s): Andrews, R. L.
• Application Number:
  US06/102,629
• Time in Patent Office: 973 Days
• Field of Search: 204/282-283, 204/267, 204/269-270, 204/263-266, 204/253-256, 204/98, 204/128
• US Class Current: 204/263
• CPC Class Codes: C25B 1/46 in diaphragm cells
• CPC Class Codes: C25B 9/19 with diaphragms
• CPC Class Codes: C25B 9/65 Means for supplying current; Electrode connections; Electric inter-cell connections

Abstract

A cell is provided having an anode and cathode separated by an ion permeable membrane or diaphragm wherein an electrode layer is bonded to or otherwise embedded in on at least one and usually to both sides of the membrane. Polarity is imparted to a bonded or embedded electrode by pressing a crinkled resiliently compressible fabric against the membrane carrying the electrode layer. This fabric is substantially coextensive with the electrode layer and is constructed so that when compressed it exerts a substantially uniform elastic reaction pressure against the membrane carrying the electrode layer or a pliable foraminous sheet, i.e. screen, interposed between the membrane carrying the electrode layer and the resiliently compressible fabric. The resiliently compressible fabric has the ability of also transmitting pressure laterally so that pressure applied may distribute across the entire area of the layer and tendency to have local areas of too low or too high pressure is minimized or reduced.

Chlorine or other halogen is produced by feeding an aqueous alkali metal halide or aqueous hydrogen halide to the anode chamber. Alkali is produced in the cathode chamber and withdrawn.

Claims

1. An electrolytic cell which comprises a flexible ion permeable diaphragm having at least one complaint electrode layer bonded to or otherwise incorporated on one side thereof, a current distributor bearing against the layer, said distributor having an electroconductive surface adapted to impart polarity to the layer, and a cooperating counter electrode disposed at the other side of the diaphragm, said current distributor or said counter electrode comprising a resiliently compressible mat coextensive with said electrode layer dimensions, said mat being capable of being compressed in the direction of the diaphragm and to exert an elastic reaction force towards the diaphragm at a multiplicity of pressure points and capable to transfer excess resilient force acting on one or more pressure points to other neighbouring pressure points in a lateral direction along a major dimension of the mat whereby compressing pressure can be effectively distributed over the entire surface of the layer, said mat being open to permit flow of electrolyte through it means slideable with respect to the mat to compress the mat toward the diaphragm and a rigid support on the other side of the flexible diaphragm to restrain diaphragm displacement.

2. The cell of claim 1 wherein the diaphragm is supported in an upright alignment.

3. The cell of claim 1 wherein the resiliently compressible mat comprises a pliable electroconductive screen on the surface of the mat facing towards the diaphragm and a separate compressible fabric slideable with respect to the screen said fabric being resiliently compressible, the screen being less compressible than the fabric.

4. The cell of claim 3 wherein the open volume of the compressible fabric is not less than 25 percent of the volume occupied by the fabric.

5. The cell of claim 1 wherein the mat is electroconductive metal.

6. The cell of claim 1 wherein the mat is wrinkled metal mesh.

7. The cell of claim 6 wherein the compressing means compresses the mat to at least one half of its volume.

8. The cell of claim 1 wherein the mat is metal mesh crimped in the form of pluralities of adjacent waves.

9. The cell of claim 1 wherein the diaphragm is a flexible ion exchange, fluorocarbon polymer.

10. The cell of claim 9 wherein the compressing means is capable of applying a pressure of at least 80 grams per centimeter against the diaphragm sheet.

11. An electrolytic cell which comprises an enclosure having a flexible ion permeable diaphragm sheet aligned in an upright direction;

said diaphragm sheet having electroconductive electrode layers compliant thereto bonded to the sheet on opposite sides thereof with a substantially rigidly mounted foraminous electroconductive current distributor bearing against one of said layers and a resiliently compressible current distributor bearing against the other layer;

said current distributor being compressed against the layer against which it bears and also capable of transmitting excess compressive force from one area, in a lateral direction, toward adjacent lower pressure areas and means slideable with respect to said distributor to compress the distributor against the layer.

12. The cell of claim 11 wherein the mat comprises wrinkled metal mesh.

13. The cell of claim 11 wherein the mat comprises metal mesh crimped in the form of pluralities of adjacent waves.

14. The cell of claim 11 wherein the mat comprises knitted metal wires.

15. The cell of claim 11 wherein the compressible current distributor is connected to the negative pole of an electrolizing potential source.

16. The cell of claim 11 wherein the distributor comprises a plurality of compressible adjacent metal wire helices.

17. The cell of claim 16 wherein the helices are interwined.

18. The cell of claim 11 wherein the compressible mat has curved springy elements which extend across the thickness of the sheet and which are compressible and impart resilience to the sheet.

19. An electrolyte cell which comprises a flexible ion permeable membrane having opposed gas and liquid permeable electrodes in contact with opposite sides thereof and means to impart polarity to at least one of said electrodes comprising a resilient mat comprising a resiliently compressible undulating metal wire mat open to gas and electrolyte flow, means slideable with respect to the mat to compress said mat against the electrode and a rigid support on the opposite side of the flexible diaphragm to restrain diaphragm displacement.

20. The cell of claim 19 wherein the mat engages the cell cathode.

21. The cell of claim 19 wherein the mat comprises helically wound wire.

22. The cell of claim 19 wherein the mat comprises undulating knitted wire mesh.

23. The cell of claim 19 wherein the membrane is a flexible ion exchange fluorocarbon polymer.

24. The cell of claim 19 wherein the compressing means compresses the mat to at least one half its volume.

25. The cell of claim 24 wherein the mat is sufficiently open to have an open volume of not less than 25 percent of the mat volume and wherein the mat and the electrodes are vertical.

26. The cell of claim 19 wherein the electroconductive, electrode screen is disposed between the mat and the membrane.

27. The cell of claim 26 wherein the screen has a finer mesh than the network of the mat.

28. The cell of claim 19 wherein the membrane is flexible and means more rigid than the mat are provided on the side of the membrane opposite to said mat to support the membrane.

29. The cell of claim 19 wherein mat surfaces are moveable with respect to pressure surfaces.

30. The cell of claim 19 wherein the mat has a void space of at least 50% of its volume.

36. The cell of claim 19 or 31 wherein the mat is compressed 10% or more of its uncompressed thickness.

37. The cell of claim 19 or 31 wherein the diaphragm is an upright sheet and the mat is sufficiently open to permit flow of electrolyte and gas along the diaphragm.

38. The cell of claim 19 or 31 wherein the mat is cathodic and the anode extends along the opposite side of the diaphragm.

39. The cell of claim 19 or 31 wherein the mat is cathodic and gas and electrolyte to flow edgewise therethrough.

31. An electrolytic cell comprising a vertical flexible ion permeable diaphragm having opposed electrodes on opposite sides thereof, at least one of said electrodes comprising a compressible resilient, electrolyte-permeable mat open to gas and electrolyte flow and having a conductive polarized electrode surface associated therewith in contact with the diaphragm and means slideable with respect to the mat for compressing the mat against the diaphragm and more rigid means on the opposite side of the diaphragm to support the diaphragm.

32. The cell of claim 31 wherein the polarized surface comprises a conductive screen slideable with respect to the mat between the mat and the diaphragm.

33. The cell of claim 32 wherein the conductive screen is of finer mesh size than the mat.

34. The cell of claim 31 wherein the diaphragm is a cation exchange polymer, the mat is cathodically polarized and a screen of finer mesh than the mat is interposed between the mat and the diaphragm.

35. The cell of claim 31 wherein the mat is compressible to at least 50 percent of its volume while retaining an open volume.

40. An electrolytic cell which comprises a flexible ion permeable diaphragm having opposed gas and liquid permeable electrodes in contact with opposite sides thereof, at least one of said electrodes comprising a compressible resilient electrolyte permeable mat open to gas and electrolyte flow and having a conductive polarized electroconductive surface associated therewith and in contact with the diaphragm and a less compressible electroconductive screen interposed between the mat and the diaphragm.

41. The cell of claim 40 wherein the screen is of finer mesh than the mat.

42. The cell of claim 40 or 41 wherein the mat is compressible at least 10% of its thickness.

43. The cell of claim 40 or 42 wherein the diaphragm has an electrode layer bonded to the diaphragm and between the screen and the diaphragm.

44. The cell of claim 40 wherein the mat is cathodically polarized and the diaphragm has an opposed electrode on the side remote from the mat and said electrode provides the diaphragm with support more rigid than the mat.

45. An electrolytic cell having an anode and a cathode separated by a flexible ion permeable diaphragm, one of said electrodes comprising a planar backwall and a compressible resilient electroconductive electrolyte permeable mat having an electrodic surface associated therewith and between the backwall and the diaphragm, means to compress the mat and the backwall against the diaphragm and a more rigid support for the diaphragm on the opposite side thereof.

46. The cell of claim 45 wherein the mat is cathodic.

47. The cell of claim 45 or 46 wherein the diaphragm is an upright sheet and the mat extends along the diaphragm and means are provided to flow electrolyte through the mat and along the diaphragm and a less yieldable electrode is in contact, with the diaphragm on the opposite side thereof.