Method for starting a chlor-alkali diaphragm cell
AssigneePPG Industries, Inc.
InventorBernard A. Maloney
Life of this patent
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Abstract
Describes adding an anolyte soluble amphoteric material, e.g., an aluminum compound, to the anolyte of a chlor-alkali diaphragm cell having a synthetic diaphragm during the start-up period of the cell to reduce the permeability of the diaphragm. Complementary inorganic porosity modifying materials, e.g., magnesium materials such as magnesium chloride, and clays are also added to the anolyte during the start-up period of the cell.
Claims18
In the process of operating a chlor-alkali electrolytic cell having a synthetic liquid permeable diaphragm separating the anolyte compartment from the catholyte compartment, the improvement which comprises introducing into the anolyte compartment during the cell start-up period a permeability moderating amount of inorganic amphoteric material that is soluble in the anolyte, that has an insoluble form under the conditions existing within the diaphragm, and that is dissolved by product catholyte liquor.
In the process of operating a chlor-alkali electrolytic cell for the electrolysis of sodium chloride brine, said cell having a synthetic liquid permeable diaphragm separating the anolyte compartment from the catholyte compartment, the improvement which comprises introducing into the anolyte compartment during the cell start-up period a permeability moderating amount of an amphoteric aluminum compound selected from aluminum chloride, aluminum sulfate, aluminum nitrate, hydrates of said aluminum compounds and readily soluble forms of aluminum hydroxide.
Dependencies are inferred from the claim text.