Ppg Industries Ohio, Inc.

Axiall Ohio, Inc.

Eagle Controlled 2 Ohio Spinco, Inc.

Eagle US 2 LLC

Henry W Schussler

David R Bush

Craig R Long

Joseph R Cimini

Robert A Fast

Berry G Garrard

Steven T Richardson

Described is a method for improving the operation of an electrolytic cell having an anolyte compartment, a catholyte compartment and a synthetic diaphragm separating the compartments, wherein liquid anolyte is introduced into the anolyte compartment and flows through the diaphragm into the catholyte compartment, which method involves introducing particulate material comprising halocarbon polymer short fiber, e.g., fluorocarbon polymer short fiber, into the anolyte compartment in amounts sufficient to lower the flow of liquid anolyte through the diaphragm into the catholyte compartment. In the case of an electrolytic cell wherein aqueous alkali metal chloride, e.g., sodium chloride, anolyte is introduced continuously into the anolyte compartment, thereby to produce a catholyte liquor containing alkali metal hydroxide and hypochlorite ion, the foregoing method is useful for decreasing the concentration of hypochlorite ion in the catholyte liquor and oftentimes increasing the concentration of alkali metal hydroxide in the catholyte liquor. Also describes adding at least one member chosen from halocarbon polymer microfibril, halocarbon polymer fiber, clay mineral, oxides and/or hydroxides of alkaline earth metals, and zirconium oxide/hydroxide in conjunction with the halocarbon polymer short fiber to the anolyte compartment, e.g., while the cell is operating.

Method of operating a diaphragm electrolytic cell

Describes a liquid-permeable diaphragm assembly for use in electrolytic cells, e.g., chlor-alkali electrolytic cells. The diaphragm assembly includes a foraminous cathode, a liquid permeable base mat comprising synthetic polymeric material that is at least partially resistant to the environment within the electrolytic cell on the foraminous cathode, and a topcoat of water-insoluble particulate material on the base mat. The topcoat is deposited on the base mat from an aqueous slurry comprising (i) at least one oxide, boride, carbide, nitride or silicate of a valve metal, (ii) clay mineral, (iii) hydrous metal oxide chosen from the hydrous oxides of magnesium, the hydrous oxides of zirconium, and mixtures of such hydrous metal oxides, and (iv) alkali metal polyphosphate.

Diaphragm for electrolytic cell

Describes a diaphragm for an electrolytic diaphragm cell, e.g., a chlor-alkali cell, in which the diaphragm comprises fibrous material substantially resistant to the environment within the electrolytic cell and spheroidal ceramic microspheres at least partially resistant to the environment within the electrolytic cell associated with said diaphragm. Also describes a diaphragm for an electrolytic cell in which the diaphragm comprises a base mat of fibrous material chosen from asbestos fibers, resin-modified asbestos fibers, synthetic fibers, or mixtures of such fibers on which base mat is applied a coating comprising spheroidal ceramic microspheres. Further describes a synthetic diaphragm for an electrolytic cell, e.g., a chlor-alkali cell, on which is applied a coating comprising substantially water-insoluble inorganic particulate material, e.g., clay material, and spheroidal ceramic microspheres. Still further describes adding a dopant composition comprising spheroidal ceramic microspheres to the anolyte compartment of an electrolytic cell, e.g., a chlor-alkali cell, while the cell is operating.

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.

Describes a cathode assembly for electrolytic cells, e.g., chlor-alkali electrolytic cells, comprising a foraminous cathode substrate, a deposited erodible mat comprising synthetic (man-made) fibers, e.g., polyamide (nylon) fibers, on the foraminous surface of said cathode substrate, and a synthetic diaphragm on said erodible mat. Also described is a method for preparing the cathode assembly that comprises depositing a mat of erodible synthetic fibers on the active surface of the foraminous cathode, e.g., by drawing an aqueous slurry of the erodible synthetic fibers through the foraminous cathode, and subsequently forming, e.g., by vacuum deposition, a synthetic diaphragm on the erodible mat.

Oxychlorination catalyst is produced by mixing together wet support material, copper chloride or precursor thereof, to form a paste, wherein the wet support material is wet clay, wet silica, wet silica gel, wet alumina, wet diatomaceous earth, or a mixture of two or more thereof; removing water from the paste to produce a substantially dry mixture; and calcining the substantially dry mixture at elevated temperatures to produce a calcined mixture wherein alkali metal chloride or precursor thereof is mixed with the wet support material or an aqueous solution of alkali metal chloride or precursor thereof is applied to the paste, the substantially dry mixture, or the calcined mixture and the water of the aqueous solution is substantially removed. Preferably wet attapulgus clay, cupric chloride, and potassium chloride are mixed to form the paste.

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Harrison City, PA, United States of America

Henry W Schussler