Abstract: A process for removing chlorine gas from the tail gas stream of a chlor/alkali plant or other chemical processes comprising the steps of: (a) contacting a chlorine-, hydrogen-, and carbon dioxide-containing tail gas stream with a zeolite molecular sieve having a molecular pore diameter greater than the molecular diameter of the carbon dioxide and hydrogen and smaller than the molecular diameter of chlorine so that at least a portion of the carbon dioxide is absorbed onto the molecular sieve, and thereby producing a purified tail gas stream that contains substantially all of the chlorine and hydrogen values and a reduced amount or no amount of carbon dioxide values; and (b) contacting the purified tail gas stream with an aqueous sodium hydroxide scrubbing solution in order to remove substantially all of the chlorine values from the purified tail gas stream, whereby producing a purified sodium hypochlorite solution that is substantially free of sodium carbonate.

Abstract: A process for reducing the corrosion of nickel metal in an alkali metal hydroxide evaporator equipment which comprises the step of impressing a total protection potential directly upon the nickel metal material in alkali metal hydroxide evaporator that is in contact with an aqueous alkali metal hydroxide solution during evaporation of that solution; said total potential being sufficient to reduce the amount of corrosion of the nickel metal to an oxide that may dissolve in the alkali metal hydroxide solution.

Abstract: A propellant module assembly is adapted for containing a liquid propellant which is used to inflate a vehicular air bag. The module assembly includes an igniter; a liquid propellant; a propellant and igniter capsule; and a rupturable closure member. The capsule and rupturable member are compatible with, and will not deteriorate as a result of contact with the liquid propellant. The liquid propellant, when ignited, will not produce toxic gases, and will not subject vehicle occupants to the possibility of chemical burns, as can occur with solid propellants.

Abstract: The present invention relates to a multi-step process for producing HAN that is free of ammonium nitrate. The process comprises the steps of: (a) stripping ammonia from an ammonia-containing, aqueous hydroxylamine solution having a hydroxylamine concentration of at least 10% by weight based upon the weight of the hydroxylamine solution, by contacting the ammonia-containing hydroxylamine solution with a stripping agent selected from the group consisting of inert gases and steam to provide an ammonia-free, aqueous hydroxylamine solution, and (b) reacting the ammonia-free, aqueous hydroxylamine solution with aqueous nitric acid having an acid concentration of at least about 0.1%, preferably at least about 20%, based upon the weight of the aqueous nitric acid, to produce ammonium nitrate-free HAN. In another process embodiment of the invention, the above-described ammonia stripping step is not required, and the hydroxylamine concentration is at least about 0.

Abstract: The present invention relates to a multi-step process for producing HAN that is free of ammonium nitrate. The process comprises the steps of: (a) stripping ammonia from an ammonia-containing, aqueous hydroxylamine solution having a hydroxylamine concentration of at least 10% by weight based upon the weight of the hydroxylamine solution, by contacting the ammonia-containing hydroxylamine solution with a stripping agent selected from the group consisting of inert gases and steam to provide an ammonia-free, aqueous hydroxylamine solution, and (b) reacting the ammonia-free, aqueous hydroxylamine solution with aqueous nitric acid having an acid concentration of at least about 0.1%, preferably at least about 20%, based upon the weight of the aqueous nitric acid, to produce ammonium nitrate-free HAN. In another process embodiment of the invention, the above-described ammonia stripping step is not required, and the hydroxylamine concentration is at least about 0.

Abstract: A process for treating solutions of a hydroxylammonium salt containing excess acid which comprises:a) mixing the hydroxylammonium salt containing excess acid with a hydroxylammonium solution containing free hydroxylamine to produce a solution of the hydroxylammonium salt substantially free of excess acid,b) contacting a portion of the solution of the hydroxylammonium salt substantially free of excess acid with a weak base ion exchange resin to produce the hydroxylammonium solution containing free hydroxylamine, and,c) recycling the hydroxylammonium solution containing free hydroxylamine to step a).The process minimizes the decomposition of the hydroxylammonium salt solution and produces high purity hydroxylammonium nitrate solutions without directly contacting excess nitric acid with ion exchange resins. In addition to hydroxylammonium salts, the process can be used to treat any nitrate salt of an anine weak base which contains excess nitric acid.

Abstract: A process for the removal of mercury from industrial waste streams is disclosed wherein the waste stream is a nitrate based solution that has been decomposed by the addition of hypochlorite. The method involves adding a reducing agent to reduce the hypochlorite and/or adjusting the pH by the use of a strong acid to less than about 2.0, converting any residual chlorine to a soluble unreactive salt, adding a soluble precipitating agent, such as sodium sulfide, to the solution in a ratio to the mercury present of greater than 1:1 to about 2:1 to precipitate out the mercury as a mercury compound. The solution is then filtered to remove the precipitated mercury compound.

Abstract: An electrochemical cell is disclosed having a cell bottom or baseplate that has at least one drain hole therein which is fed by drain canals adjacent an end of the catholyte chamber such that the drain holes are gradually inclined to increase in depth laterally downwardly from the opposing sides of the cell toward the center and longitudinally downwardly from the opposing end of the cell toward the drain hole to permit removal or the addition of the liquid metal cathode from the angled electrolytic cell without requiring disassembly of the cell.

Abstract: A process for decomposing a solution of a hydroxylammonium compound includes raising the pH of the solution to about 8 or higher and reacting the alkaline solution with a source of hypohalite ions. The process decomposes solutions of hydroxylammonium salts in a manner which produces benign liquid and gas effluents which can be readily disposed of or discharged.

Abstract: An improved process for treating aqueous effluents and purge streams to selectively remove polluting elements such as iron, copper, lead and mercury therefrom is described. The procedure comprises contacting the effluent with a poly(dithiocarbamate) chelating agent whereby the polluting elements are absorbed. The resin is extracted with an acidic aqueous solution having a pH of from about 4 to about 6; and removing the resin. When this is done, the residual content of these polluting elements in the effluent is reduced to a level below EPA required levels so that the effluent can safely be discharged into the surrounding ecosystem. The poly(dithiocarbamate) resin containing the polluting elements can be disposed of, for example, by being deposited in an unsecured landfill.

Abstract: A process for removing chlorate ions from a recirculating anolyte brine as typically used in membrane chlor-alkali cells is disclosed. In this, a portion of the circulating brine after dechlorination and resaturation with additional alkali metal chloride is diverted and treated with a stoichiometric amount of hydrochloric acid to convert substantially all of the chlorate to chlorine gas and chloride ion. When performed in this manner, substantially lower quantities of acid are required as compared to prior art processes and the problems with the generation of ClO.sub.2 are minimized.

Abstract: A process is disclosed for substantially reducing the dissolved halogen and hypohalite ion concentration in a recycled brine from a membrane electrolytic cell with a closed loop brine system comprising the addition of a non-sulfate generating reducing agent to the brine in a less than conventional stoichiometric molar quantity in relation to each mole of available halogen and hypohalite present in the brine after the steps of dehalogenation, precipitation and pH adjustment.

Abstract: A process is described for removing available chlorine from a depleted recirculating anolyte brine of a chlor-alkali cell. After the spent brine is removed from the cell, and typically after dechlorination, it is reacted with an amount of an organic hydroxyl moiety-containing compound soluble in said brine for a residence time sufficient to substantially reduce the residual dissolved chlorine and hypohalite ion remaining in said brine prior to resaturation and reuse in said cell. Suitable hydroxyl moiety-containing compounds include alcohols and saccharides.

Abstract: A process is described for reducing the concentration of oxyhalogen impurities in an alkali metal halide brine recovered from an electrolytic cell which comprises circulating the alkali metal halide brine to a treatment zone outside of the electrolytic cell. Within the treatment zone, the alkali metal halide brine is reacted with oxalic acid while maintaining the alkali metal halide brine at a pH of less than about 4.5. A purified brine having a substantially reduced concentration of oxyhalogen impurities is recovered from the treatment zone. The process may be employed in treating brines recovered from mercury cells and membrane cells for the production of chlorine and alkali metal hydroxides and its employment results in a substantial reduction in the amount of concentrated acid required in brine treatment and a reduction in energy costs for brine purification.

Abstract: A process for removing chlorate ions from a recirculating anolyte brine as typically used in membrane chlor-alkali cells is disclosed. In this, a portion of the circulating brine after dechlorination and resaturation with additional alkali metal chloride is diverted and treated with an acidified aliphatic aldehyde to convert substantially all of the hypochlorite and chlorate to chlorine dioxide, chlorine gas and chloride ion. When performed in this manner, substantially lower quantities of acid are required as compared to prior art processes and the problems with the generation of excessive quantities of ClO.sub.2 are minimized.

Abstract: In an electrolytic filter press cell having an electrolyte fluid circulated through anode and cathode frames, a cell frame at least partially supporting an anolyte disengager and a catholyte disengager, the disengagers having at least a first flow conduit and a second flow conduit in fluid flow communication with each electrode, there is provided a variable flow restrictor in the first flow conduit from the disengagers to each electrode frame to selectively vary the flow rate of electrolyte through the disengagers to thereby control the level of foaming of the electrolyte within the disengagers to optimize the amount of gas separated out therein.

Abstract: A method of varying the flow in a flow conduit from both the anolyte disengager and the catholyte disengager to each appropriately corresponding electrode is provided to selectively vary the flow rate of electrolyte fluids through the disengagers to the appropriate electrodes to thereby control the level of foaming of the electrolyte fluids within the disengagers to prevent the blowover of foam during the separation of entrained gas from the electrolyte fluids therein.

Abstract: A method of heat sealing together two untreated layers of a sulfonated perfluorovinyl ether ion exchange diaphragm or membrane material having pendant groups predominantly in the sulfonamide form by placing a layer of untreated sulfonated perfluorovinyl ether material having pendant groups predominantly in the sulfonic acid form between the sulfonamide layers to create a "sandwich". The preferred heat sealing involves applying from 1 to 5, and preferably from 3.5 to 5.0 kg/cm.sup.2 pressure at from 260.degree. to 350.degree. C. and preferably from 280.degree. to 320.degree. C. for from 3.5 to 7.5, and preferably from 3.5 to 5.0 seconds to this "sandwich". It had been previously taught that such untreated sulfonamide layers could not be heat sealed together. The novel heat sealing technique of this invention enables fabrication of a cathode-membrane unit using ion exchange membranes having such a sulfonamide layer facing the cathode of an electrolytic cell.