Method of operating a diaphragm electrolytic cell
First Claim
1. A method for improving the operation of an electrolytic cell comprising an anolyte compartment, a catholyte compartment and a synthetic diaphragm substantially free of asbestos separating the anolyte and catholyte compartments wherein liquid anolyte is introduced into the anolyte compartment and flows through the diaphragm into the catholyte compartment, which method comprises introducing synthetic ceramic fiber chosen from fibers coin rising the oxides, nitrides, carbides, borides and silicates of metals or semimetals chosen from zirconium, silicon, aluminum, boron, magnesium and in mixtures of such metal or semimetal oxides, nitrides, carbides, borides and silicates into the anolyte compartment in amounts sufficient to lower the flow of liquid anolyte through the diaphragm into the catholyte compartment.
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Abstract
Describes a method for lowering the flow of liquid anolyte through perforations in the diaphragm of a diaphragm electrolytic cell, e.g., a chlor-alkali diaphragm electrolytic cell, comprising introducing ceramic fiber into the anolyte compartment of the electrolytic cell, e.g., during cell operation. The benefits described for lowering the flow of anolyte liquor through the diaphragm of a chlor-alkali diaphragm electrolytic cell are increasing the concentration of alkali metal hydroxide, e.g., sodium hydroxide, and decreasing the concentration of hypochlorite ion, e.g., sodium hypochlorite, in the catholyte liquor. Also describes introducing dopant material and/or fibers comprising halogen-containing polymer, e.g., fluorocarbon polymer fibers, into the anolyte compartment of the electrolytic cell in conjunction with the addition of ceramic fiber into the anolyte compartment, e.g., during cell operation.
49 Citations
16 Claims
- 1. A method for improving the operation of an electrolytic cell comprising an anolyte compartment, a catholyte compartment and a synthetic diaphragm substantially free of asbestos separating the anolyte and catholyte compartments wherein liquid anolyte is introduced into the anolyte compartment and flows through the diaphragm into the catholyte compartment, which method comprises introducing synthetic ceramic fiber chosen from fibers coin rising the oxides, nitrides, carbides, borides and silicates of metals or semimetals chosen from zirconium, silicon, aluminum, boron, magnesium and in mixtures of such metal or semimetal oxides, nitrides, carbides, borides and silicates into the anolyte compartment in amounts sufficient to lower the flow of liquid anolyte through the diaphragm into the catholyte compartment.
- 6. In the method of operating a chlor-alkali electrolytic cell comprising an anolyte compartment, a catholyte compartment and a synthetic diaphragm substantially free of asbestos separating the anolyte and catholyte compartments, wherein aqueous alkali metal chloride is introduced continuously into the anolyte compartment and passes through the diaphragm into the catholyte compartment which contains catholyte liquor comprising alkali metal hydroxide and wherein the concentration of alkali metal hydroxide in the catholyte liquor is less than the desired concentration, the improvement comprising introducing synthetic ceramic fiber chosen from fibers comprising the oxides, nitrides, carbides, borides and silicates of metals or semi-metals chosen from zirconium, silicon aluminum, boron, magnesium and mixtures of such metal or semi-metal oxides, nitrides, carbides, borides and silicates into the anolyte compartment in amounts sufficient to increase the concentration of alkali metal hydroxide in the catholyte liquor.
- 14. In the operation of a chlor-alkali electrolytic cell comprising an anolyte compartment, a catholyte compartment and a microporous synthetic diaphragm substantially free of asbestos separating the anolyte and catholyte compartments, wherein aqueous alkali metal chloride is introduced continuously into the anolyte compartment and percolates through the diaphragm into the catholyte compartment, which contains catholyte liquor comprising alkali metal hydroxide and hypochlorite ion, and wherein the concentration of hypochlorite ion in the catholyte liquor is more than the desired concentration, the improvement comprising introducing synthetic ceramic fiber chosen from fibers comprising at least on of the oxides of silicon, aluminum and zirconium into the anolyte compartment in amounts sufficient to lower the concentration of hypochlorite ion in the catholyte liquor.
Specification