Electrolyte permeable diaphragm

Claim 3

The method of claim 1 wherein the pore forming component is removed during formation of the cohesive matrix.

Claim 4

The method of claim 1 wherein the pore forming component is chosen from the group consisting of hydrocarbon resins and naturally occurring organic fibers.

Claim 5

The method of claim 3 wherein the pore forming component is a cellulosic fiber.

Claim 6

The method of claim 1 wherein the binder is a thermoplastic halocarbon resin.

Claim 7

The method of claim 5 wherein the thermoplastic halocarbon resin is chosen from the group consisting of fluorinated ethylene propylene, perfluoroalkoxy, copolymers having the moieties --CX.sub.1 X.sub.2 --CX.sub.3 X.sub.4 -- and --CY.sub.1 Y.sub.2 --CY.sub.3 Y.sub.4 --, and homopolymers having the moieties --CCY.sub.1 Y.sub.2 --CY.sub.3 F-- where X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , and Y 4 are chosen from the group consisting of --F, --Cl, and H, at least one of said X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , and Y 4 being --F.

Claim 8

The method of claim 6 wherein the thermoplastic resin is chosen from the group consisting of copolymers having a fluorocarbon resin moiety chosen from the group consisting of --CFH--CH.sub.2 --, --CF.sub.2 --CH.sub.2 --, --CF.sub.2 --CFH--, --CF.sub.2 --CF.sub.2 --, and --CF.sub.2 --CClF-- and an ethylene moiety.

Claim 9

The method of claim 1 wherein the non-asbestos structural component is a mineral fiber chosen from the group consisting of zirconia, titania, barium sulfate, barium titanate, potassium titanate, and alumina.

Claim 10

The method of claim 8 wherein the non-asbestos structural component is zirconia.

Claim 11

The method of claim 1 wherein the non-asbestos structural component is a resin capable of remaining undeformed at temperatures where the binder is thermoplastic.

Claim 12

The method of claim 10 wherein the non-asbestos structural component is polytetrafluoroethylene.

Claim 13

The method of claim 1 wherein the solvent has a viscosity greater than about 10 centipoise.

Claim 14

The method of claim 1 wherein the solvent has a density of about 1.0 to about 1.5 grams per cubic centimeter.

Claim 15

The method of claim 1 comprising coating the surface of the diaphragm with sepiolite.

Claim 16

In a method of electrolyzing an alkali metal chloride brine chosen from the group consisting of potassium chloride and sodium chloride in an electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, and an electrolyte permeable diaphragm therebetween, which method comprises feeding the brine to the anolyte compartment, imposing an electrical potential across the cell whereby to evolve chlorine at the anode, imposing a hydrostatic head across the cell whereby to drive electrolyte from the anolyte compartment to the catholyte compartment, and recovering chlorine from the anolyte compartment and cell liquor containing alkali metal chloride and alkali metal hydroxide from the catholyte compartment, the improvement wherein the diaphragm is deposited on the cathode by the method comprising: a. providing a slurry comprising a solvent, a pore forming component, a non-asbestos structural component, and a binder; b. drawing the slurry through the foraminous structure whereby to deposit the pore forming component, the non-asbestos structural component, and the binder thereon; c. forming a cohesive matrix of the non-asbestos structural component and the binder; and d. removing the pore forming component.

Claim 17

In a method of electrolyzing an alkali metal chloride brine chosen from the group consisting of potassium chloride and sodium chloride in an electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, and an electrolyte permeable diaphragm therebetween, which method comprises feeding the brine to the anolyte compartment, imposing an electrical potential across the cell whereby to evolve chlorine at the anode, imposing a hydrostatic head across the cell whereby to drive electrolyte from the anolyte compartment to the catholyte compartment, and recovering chlorine from the anolyte compartment and cell liquor containing alkali metal chloride and alkali metal hydroxide from the catholyte compartment, the improvement wherein the diaphragm is deposited on the cathode by the method comprising: a. providing a slurry comprising a solvent, a pore forming component, a non-asbestos structural component, and a binder; b. drawing the slurry through the foraminous structure whereby to deposit the pore forming component, the non-asbestos structural component, and the binder thereon; c. forming a cohesive matrix of the non-asbestos structural component and the binder; and d. removing the pore forming component.

Claim 18

The method of claim 15 wherein the pore forming component is removed during formation of the cohesive matrix.

Claim 19

The method of claim 15 wherein the pore forming component is chosen from the group consisting of hydrocarbon resins and naturally occurring organic fibers.

Claim 20

The method of claim 17 wherein the pore forming component is a cellulosic fiber.

Claim 21

The method of claim 15 wherein the binder is a thermoplastic halocarbon resin.

Claim 22

The method of claim 19 wherein the thermoplastic halocarbon resin is chosen from the group consisting of fluorinated ethylene propylene, perfluoroalkoxy, copolymers having the moieties --CX.sub.1 X.sub.2 --CX.sub.3 X.sub.4 -- and --CY.sub.1 Y.sub.2 --CY.sub.3 Y.sub.4 --, and homopolymers having the moieties --CY.sub.1 Y.sub.2 --CY.sub.3 F-- where X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , and Y 4 are chosen from the group consisting of --F, --Cl, and H, at least one of said X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , or Y 4 being --F.

Claim 23

The method of claim 6 wherein the thermoplastic resin is chosen from the group consisting of copolymers having a fluorocarbon resin moiety chosen from the group consisting of --CFH--CH.sub.2 --, --CF.sub.2 --CH.sub.2 --, --CF.sub.2 --CFH--, --CF.sub.2 --CF.sub.2 --, and --CF.sub.2 --CClF-- and an ethylene moiety.

Claim 24

The method of claim 15 wherein the non-asbestos structural component is a mineral fiber chosen from the group consisting of zirconia, titania, barium sulfate, barium titanate, potassium titanate, and alumina.

Claim 25

The method of claim 22 wherein the non-asbestos structural component is zirconia.

Claim 26

The method of claim 15 wherein the non-asbestos structural component is a resin capable of remaining undeformed at temperatures where the binder is thermoplastic.

Claim 27

The method of claim 24 wherein the non-asbestos structural component is polytetrafluoroethylene.

Claim 28

The method of claim 15 wherein the solvent has a viscosity greater than about 10 centipoise.

Claim 29

The method of claim 15 wherein the solvent has a density of about 1.0 to about 1.5 grams per cubic centimeter.

Claim 30

The method of claim 15 comprising adding sepiolite to the anolyte liquor whereby to deposit the sepiolite on the diaphragm.

Claim 31

In an electrolytic cell having an anode in an anolyte compartment, a foraminous cathode in a catholyte compartment, and an aqueous alkali metal chloride permeable diaphragm therebetween, said diaphragm being deposited on the foraminous cathode, the improvement wherein the diaphragm is prepared by the method comprising: a. providing a slurry comprising a solvent, a pore forming component, a non-asbestos structural component, and a binder; b. drawing the slurry through the foraminous structure whereby to deposit the pore forming component, the non-asbestos structural component and the binder thereon; c. forming a cohesive matrix of the non-asbestos structural component and the binder; and d. removing the pore forming component.

Claim 32

In an electrolytic cell having an anode in an anolyte compartment, a foraminous cathode in a catholyte compartment, and an aqueous alkali metal chloride permeable diaphragm therebetween, said diaphragm being deposited on the foraminous cathode, the improvement wherein the diaphragm is prepared by the method comprising: a. providing a slurry comprising a solvent, a pore forming component, a non-asbestos structural component, and a binder; b. drawing the slurry through the foraminous structure whereby to deposit the pore forming component, the non-asbestos structural component and the binder thereon; c. forming a cohesive matrix of the non-asbestos structural component and the binder; and d. removing the pore forming component.

Claim 33

The electrolytic cell of claim 29 wherein the pore forming component is removed during formation of the cohesive matrix.

Claim 34

The electrolytic cell of claim 24 wherein the pore forming component is chosen from the group consisting of hydrocarbon resins and naturally occurring organic fibers.

Claim 35

The electrolytic cell of claim 31 wherein the pore forming component is a cellulosic fiber.

Claim 36

The electrolytic cell of claim 29 wherein the binder is a thermoplastic halocarbon resin.

Claim 37

The electrolytic cell of claim 33 wherein the thermoplastic halocarbon resin is chosen from the group consisting of fluorinated ethylene propylene, perfluoroalkoxy, copolymers having the moieties --CX.sub.1 X.sub.2 --CX.sub.3 X.sub.4 -- and --CY.sub.1 Y.sub.2 --CY.sub.3 Y.sub.4 --, and homopolymers having the moieties --CY.sub.1 Y.sub.2 --CY.sub.3 F-- where X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , and Y 4 are chosen from the group consisting of --F, --Cl, and H, at least one of said X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , or Y 4 being --F.

Claim 38

The electrolytic cell of claim 34 wherein the thermoplastic resin is chosen from the group consisting of copolymers having a fluorocarbon resin moiety chosen from the group consisting of --CFH--CH.sub.2 --, --CF.sub.2 --CH.sub.2 --, --CF.sub.2 --CFH--, --CF.sub.2 --CF.sub.2 --, and --CF.sub.2 --CClF-- and an ethylene moiety.

Claim 39

The electrolytic cell of claim 29 wherein the non-asbestos structural component is a mineral fiber chosen from the group consisting of zirconia, titania, barium sulfate, barium titanate, potassium titanate, and alumina.

Claim 40

The electrolytic cell of claim 36 wherein the non-asbestos structural component is zirconia.

Claim 41

The electrolytic cell of claim 29 wherein the non-asbestos structural component is a resin capable of remaining undeformed at temperatures where the binder is thermoplastic.

Claim 42

The electrolytic cell of claim 38 wherein the non-asbestos structural component is polytetrafluoroethylene.

Claim 43

The electrolytic cell of claim 29 wherein the solvent has a viscosity greater than about 10 centipoise.

Claim 44

The electrolytic cell of claim 29 wherein the solvent has a density of about 1.0 to about 15 grams per cubic centimeter.

Claim 45

The electrolytic cell of claim 29 comprising coating the surface of the diaphragm with sepiolite.

Claim 46

A cathode-diaphragm unit comprising a perforate cathode having an electrolyte permeable diaphragm thereon comprising non-asbestos fibers and a binder, said diaphragm prepared by the method comprising: a. providing a slurry comprising a solvent, a pore forming component, a non-asbestos structural component, and a binder; b. drawing the slurry through the foraminous structure whereby to deposit the pore forming component, the non-asbestos structural component and the binder thereon; c. forming a cohesive matrix of the non-asbestos structural component and the binder; and d. removing the pore forming component.

Claim 47

A cathode-diaphragm unit comprising a perforate cathode having an electrolyte permeable diaphragm thereon comprising non-asbestos fibers and a binder, said diaphragm prepared by the method comprising: a. providing a slurry comprising a solvent, a pore forming component, a non-asbestos structural component, and a binder; b. drawing the slurry through the foraminous structure whereby to deposit the pore forming component, the non-asbestos structural component and the binder thereon; c. forming a cohesive matrix of the non-asbestos structural component and the binder; and d. removing the pore forming component.

Claim 48

The cathode-diaphragm unit of claim 43 wherein the pore forming component is removed during formation of the cohesive matrix.

Claim 49

The cathode-diaphragm unit of claim 43 wherein the pore forming component is chosen from the group consisting of hydrocarbon resins and naturally occurring organic fibers.

Claim 50

The cathode-diaphragm unit of claim 45 wherein the pore forming component is a cellulosic fiber.

Claim 51

The cathode-diaphragm unit of claim 43 wherein the binder is a thermoplastic halocarbon resin.

Claim 52

The cathode-diaphragm unit of claim 47 wherein the thermoplastic halocarbon resin is chosen from the group consisting of fluorinated ethylene propylene, perfluoroalkoxy, copolymers having the moieties --CX.sub.1 X.sub.2 --CX.sub.3 X.sub.4 -- and --CY.sub.1 Y.sub.2 --CY.sub.3 Y.sub.4 --, and homopolymers having the moieties --CY.sub.1 Y.sub.2 --CY.sub.3 F-- where X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , and Y 4 are chosen from the group consisting of --F, --Cl, and H, at least one of said X 1 , X 2 , X 3 , X 4 , Y 1 , Y 2 , Y 3 , or Y 4 being --F.

Claim 53

The cathode-diaphragm unit of claim 48 wherein the thermoplastic resin is chosen from the group consisting of copolymers having a fluorocarbon resin moiety chosen from the group consisting of --CFH--CH 2 --, --CF 2 --CH 2 --, --CF 2 --CFH--, --CF 2 --CF 2 -- and --CF 2 --CClF--, and an ethylene moiety.

Claim 54

The cathode-diaphragm unit of claim 43 wherein the non-asbestos structural component is a mineral fiber chosen from the group consisting of zirconia, titania, barium sulfate, barium titanate, potassium titanate, and alumina.

Claim 55

The cathode-diaphragm unit of claim 50 wherein the non-asbestos structural component is zirconia.

Claim 56

The cathode-diaphragm unit of claim 43 wherein the non-asbestos structural component is a resin capable of remaining undeformed at temperatures where the binder is thermoplastic.

Claim 57

The cathode-diaphragm unit of claim 52 wherein the non-asbestos structural component is polytetrafluoroethylene.

Claim 58

The cathode-diaphragm unit of claim 43 wherein the solvent has a viscosity greater than about 10 centipoise.

Claim 59

The cathode-diaphragm unit of claim 43 wherein the solvent has a density of about 1.0 to about 1.5 grams per cubic centimeter.

Claim 60

The cathode-diaphragm unit of claim 43 comprising coating the surface of the diaphragm with sepiolite.