PARTIALLY CONDUCTIVE CHLOR-ALKALI DIAPHRAGMS
A non-asbestos diaphragm unit, such as for use in a chlor-alkali diaphragm cell, includes carbonized organic fibers that are treated to impart partial conductivity to the fibers of up to 1000 mhos and in turn to the diaphragms in which the fibers are incorporated. The partial conductivity of the fibers and the resulting diaphragm improves the life of new non-asbestos diaphragm constructions as well as pre-existing and previously in-use non-asbestos diaphragms that are reinforced, renewed and/or repaired with the fibers having partial conductivity.
1 . A diaphragm unit comprising partially carbonized and partially conductive organic fibers derived from a non-halogenated source, wherein said fibers have an electrical conductance across compressed material of greater than 0 mhos and up to 1000 mhos.
2 . The diaphragm unit of claim 1 , wherein the carbonized organic fibers include heat-treated oxidized polyacrylonitrile fibers.
3 . The diaphragm unit of claim 1 , wherein the carbonized organic fibers include heat-treated oxidized polymer.
4 . The diaphragm unit of claim 1 , wherein the unit is a single layer.
5 . The diaphragm unit of claim 1 , wherein the unit includes multiple layers.
6 . The diaphragm unit of claim 1 , wherein the unit is included in a chlor-alkali diaphragm configured with sufficient electrical conductivity to (a) make produced cell liquor substantially free of hypochlorite and (b) limit production of chlorine gas and hydrogen gas to maintain hydrogen gas concentration below about 4%.
7 . The diaphragm unit of claim 1 , wherein the diaphragm unit includes one or more types of inorganic particles and one or more types of binders.
8 . The diaphragm unit claim 7 , wherein the one or more types of binders include fluoropolymers.
9 . The diaphragm unit claim 7 , wherein the one or more types of binders include non-fluorinated chemicals.
10 . The diaphragm unit of claim 7 wherein the one or more types of inorganic particles include zirconium dioxide particles.
11 . The diaphragm unit of claim 7 , wherein the one or more types of inorganic particles include attapulgite clay particles.
12 . The diaphragm unit of any of claim 7 , wherein the one or more types of inorganic particles include talc.
13 . The diaphragm unit of claim 1 , further comprising the carbonized organic fibers including fibers having a length of from about 20 microns to about 100 mm.
14 . The diaphragm unit of claim 1 , wherein the carbonized organic fibers include fibers having different lengths.
15 . The diaphragm unit of claim 1 , wherein the unit was previously used as a chlor-alkali diaphragm and physically reinforced with the fibers.
16 . The diaphragm unit of claim 1 , wherein the unit is a non-asbestos chlor-alkali diaphragm.
17 . A diaphragm unit comprising a non-asbestos chlor-alkali diaphragm having thermally treated under inert atmosphere and partially conductive oxidized polyacrylonitrile fibers.
18 . The diaphragm unit of claim 17 , wherein the unit was previously used as a chlor-alkali diaphragm and physically reinforced with the fibers.
19 . The diaphragm unit of claim 17 , wherein the unit is configured with sufficient electrical conductivity to (a) make produced cell liquor substantially free of hypochlorite and (b) limit production of chlorine gas and hydrogen gas to maintain hydrogen gas concentration below about 4%.
20 . The diaphragm unit of claim 17 , wherein the diaphragm unit includes one or more types of inorganic particles and one or more types of binders.
21 . The diaphragm unit claim 17 , wherein the one or more types of binders include fluoropolymers.
22 . The diaphragm unit claim 17 , wherein the one or more types of binders include non-fluorinated chemicals.
23 . The diaphragm unit of claim 17 , wherein the one or more types of inorganic particles include zirconium dioxide particles.
24 . The diaphragm unit of claim 17 , wherein the one or more types of inorganic particles include attapulgite clay particles.
25 . The diaphragm unit of any of claim 17 , wherein the one or more types of inorganic particles include talc.
26 . The diaphragm unit of claim 17 , wherein the fibers include fibers having different lengths.
27 . A composition comprising thermally treated under inert atmosphere, partially carbonized and partially conductive organic fibers derived from a non-halogenated source, wherein said fibers have an electrical conductance of greater than 0 mhos and up to 1000 mhos as measured across compressed material.
28 . The composition of claim 26 , wherein the carbonized organic fibers include heat-treated oxidized polyacrylonitrile fibers.
29 . The composition of claim 27 , wherein said composition physically reinforces a previously used diaphragm unit.
30 . The composition of claim 27 , wherein said composition is integrated in a chlor-alkali diaphragm.