Abstract: A method of activating a carbonaceous electrode is disclosed which comprises the steps of heating the electrodes to a desired temperature in water to remove surface debris from said electrodes, providing a negative electrode and a carbonaceous positive electrode spaced apart from each other, providing an aqueous electrolyte having a predetermined concentration of sulfuric acid therein and circulating the sulfuric acid solution through the porous positive electrode, passing an electrical current through the positive and negative electrodes for a predetermined time period sufficient to modify the pore structure of the positive electrode, rinsing said positive electrode, heating said electrode at a desired temperature for a desired period of time to substantially remove the activation layer and surface compound of oxygen and hydrogen on the electrode. The electrodes of the present invention are utilized in molten salt lithium-aluminum/chloride battery systems.

Abstract: In a process for making chlorine electrolytically in which a build-up of nitrogen trichloride occurs in the bottoms of cooling apparatus, a method and apparatus is provided wherein the nitrogen trichloride is dissolved in an organic solvent such as carbon tetrachloride, the chlorine removed, and the solution treated to destroy the otherwise hazardous nitrogen trichloride. The solvent is then separated and recycled to avoid environmentally undesirable waste products.

Abstract: Discrete thermoplastic fibers of fluorohydrocarbons and other self-bonding thermoplastic fibers are deployed as separators or diaphragms in electrochemical cells.

Abstract: Small quantities of metal ions can be removed from an aqueous solution by subjecting the solution to an electric current in the presence of an anode and a fibrous metal cathode. The invention also provides an electrolytic apparatus having such electrodes. The process is particularly adaptable to the removal of mercury contamination from liquid brine streams.

Abstract: Initial cell voltages are reduced by decreasing the resistance of the diaphragm through a degassing procedure prior to or at installation thereof. This degassing procedure involves subjecting the diaphragm to subatmospheric pressure while contacting the diaphragm with electrolyte, said electrolyte being an aqueous saline solution having a surface active agent therein in an amount sufficient to reduce the surface tension below the critical surface tension for wetting the fibers, and increasing the pressure to atmospheric or cell working pressure to force electrolyte solution into the interstices of the diaphragm.

Abstract: Fibers about micron size in cross-section of certain fluorine-containing polymers can be treated after being deposited as a diaphragm, either during operation or separately before installation, so that they develop a 0.25-millimeter-thick ply on either side of a central body which is substantially different in chemical composition. This yields a diaphragm 1 to 5 millimeters thick which has a Mullen burst strength approximately three to five times greater than that of an untreated diaphragm (20-25 pounds per square inch versus 5 to 7 pounds per square inch) and a remarkably improved service life in the treated diaphragm (200 days and up) in comparison with such untreated diaphragm (30 days or less). Use of a polymer based upon a major proportion of chlorotrifluoroethylene appears to be required. This discovery is economically significant, in that it is an essential element in the technology of the replacement of asbestos diaphragms now used with a synthetic material.

Abstract: An especially efficient and durable electrolytic cell is provided by utilizing a combined cathode and diaphragm unit wherein the cathode is made by spray coating a ferrous metal substrate with a powder metal having lower hydrogen overvoltage than said substrate to form a protected cathode surface having a larger surface area than the substrate, and vacuum depositing a polymer impregnated asbestos fiber diaphragm onto a spray coated surface of the cathode to form a fibrous diaphragm thereon. Preferably, the cathode surface is made with nickel and the polymer impregnated asbestos diaphragm contains from about 10 to about 30 percent based on the weight of asbestos of an organic cementing agent such as a fluorohydrocarbon polymer.

Abstract: An especially efficient and durable electrolytic cell is provided by utilizing a combined cathode and diaphragm unit wherein the cathode is made by spray coating a ferrous metal substrate with a powder metal having lower hydrogen overvoltage than said substrate to form a protected cathode surface having a larger surface area than the substrate, and vacuum depositing fluorinated hydrocarbon polymer fibers onto the spray coated surface of the cathode to form a fibrous diaphragm securely adhered thereto. Preferably, the cathode surface is made with nickel and the fluorinated hydrocarbon polymer is selected from the group consisting of homopolymers of chlorotrifluoroethylene and copolymers of chlorotrifluoroethylene and at least one compatible monomer with units of chlorotrifluoroethylene accounting for at least 80 percent of the monomeric units of said copolymer.

Abstract: In a process for making chlorine electrolytically in which a build-up of nitrogen trichloride occurs in the bottoms of cooling apparatus, a method and apparatus is provided wherein the nitrogen trichloride is dissolved in an organic solvent such as carbon tetrachloride, the chlorine removed, and the solution treated to destroy the otherwise hazardous nitrogen trichloride. The solvent is then separated and recycled to avoid environmentally undesirable waste products.

Abstract: Synthetic-fiber diaphragms are further improved by incorporating in the diaphragm an effective proportion of a suitable inorganic material such as TiO.sub.2, BaSO.sub.4 or K.sub.2 Ti.sub.8 O.sub.17, which is more hydrophilic than the fluoropolymer forming the diaphragm. This is done either by mixing the inorganic material with the resin before it is made into fiber or by supplying sub-micron-sized particles of the inorganic material, during or even after diaphragm formation. A principal benefit is that this lowers the cell voltage which is required during an initial period (up to about 300 hours) of the operation of a chlor-alkali cell provided with such a diaphragm, making it possible to avoid such drawbacks as suffering an initial period of low production or the necessity of providing external cooling to the cell during such an initial period.

Abstract: Fibers about micron size in cross-section of certain fluorine-containing polymers can be treated after being deposited as a diaphragm, either during operation or separately before installation, so that they develop a 0.25-millimeter-thick ply on either side of a central body which is substantially different in chemical composition. This yields a diaphragm 1 to 5 millimeters thick which has a Mullen burst strength approximately three to five times greater than that of an untreated diaphragm (20-25 pounds per square inch versus 5 to 7 pounds per square inch) and a remarkably improved service life in the treated diaphragm (200 days and up) in comparison with such untreated diaphragm (30 days or less). Use of a polymer based upon a major proportion of chlorotrifluoroethylene appears to be required. This discovery is economically significant, in that it is an essential element in the technology of the replacement of asbestos diaphragms now used with a synthetic material.

Abstract: A ferrous metal cathode used in a chlor-alkali electrolytic cell has a metallic coating deposited thereon. The metallic coating is applied by either flame spraying or plasma spraying a powdered metal onto the ferrous metal surface. The metals which are utilized are those having a lower hydrogen overvoltage than iron.

Abstract: Electrolytic filter press cell frames are provided with a polymeric protective covering which is either directly laminated thereonto or otherwise secured thereto. The protective covering is, preferably, a fluorinated hydrocarbon.

Abstract: Brine from a conventional treatment process is pre-filtered prior to the electrolysis of same by a method which includes the steps of: (a) heating the brine, (b) adding sodium carbonate thereto, (c) stirring the solution, (d) allowing the solution to settle, and (e) passing the solution through an absolute membrane filter. The filter "polishes" the brine feed by removing the high hardness ions.

Abstract: In an electrolytic cell for the production of halogen and caustic from an aqueous alkali metal halide solution containing anode and cathode compartments separated by a diaphragm an improved diaphragm is provided. The diaphragm is a porous sheet material made of a tetrafluoroethylene polymer having a low amorphous content and a micro-structure characterized by nodes interconnected by fibrils having a porosity of about 50 to 90 percent and a very tortuous path of interconnection. The improved diaphragm has an extremely long service life.