Abstract: A diaphragm for use in the electrolysis of aqueous solutions of ionizable compounds in electrolytic diaphragm cells is comprised of a support fabric impregnated with particles of a siliceous composition having the formula:(X).sub.m (Si).sub.p (O).sub.q (H).sub.r.nH.sub.2 OwhereinX is at least one metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Ti, Zr, Al, Zn and mixtures thereof;p is a number from 1 to about 16;m is zero to about p;q is a number from 2 to about 5p+r;r is zero to about 4p; andn is zero to about 30.The siliceous compositions are capable of undergoing hydration when in contact with at least one of the ionizable compounds in the electrolytic cell. The support fabric has an electroconductive zone along one side.The diaphragms are physically and chemically stable, provide reduced cell voltages during operation of the cell and have increased operational life.

Abstract: Cationic contaminants are removed from an alkali metal chloride brine in a process which comprises contacting the brine with solid particles of a magnesium-containing silicate having a mole ratio of silicon to magnesium of at least about 1:1. The cationic contaminants in the brine adhere to the magnesium-containing silicate particles and the concentration of the cationic contaminants are thereby reduced. A purified brine is obtained by removing the magnesium-containing silicate having cationic contaminants adhering thereto.Elements of Groups VIII, IV, and II can readily be removed from brines used in electrolytic processes such as the production of chlorine and alkali metal hydroxides or alkali metal chlorates.

Abstract: A coated, rounded, solid calcium hypochlorite granule is described which is comprised of granular calcium hypochlorite encapsulated with a plurality of layers of an inorganic salt other than calcium hypochlorite. The inorganic salt is admixed with sufficient alkaline material to form a coating which has a pH in dilute aqueous solution at ambient temperature of at least about nine or higher. The inorganic salt is selected from a group consisting of the chloride, chlorate, nitrate, bromide, bromate and sulfate of an alkali metal. The alkaline material is selected from the group consisting of calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium hydroxide and mixtures thereof. The inorganic salt coating comprises from about 4 to about 45 percent by weight of the calcium hypochlorite granule. The coated, rounded, solid granule of this invention is highly stable and resists chemical decomposition and dusting during storage.

Abstract: Calcium hypochlorite compositions useful as bleaching agents and disinfectants are produced by the reaction of solid granular hydrated lime and a solid granular alkali metal hydroxide with chlorine gas. The process takes place in the absence of a solvent and produces dry, free-blowing Ca(OCl).sub.2 compositions.

Abstract: An improved process for precipitating and recovering lime by reacting an aqueous solution of calcium hypochlorite with an alkaline compound is described. The pH of the resulting lime slurry is maintained in the range from about 11 to about 13.0, whereby hemi-basic calcium hypochlorite crystals form in the slurry. When the slurry is filtered or otherwise separated to recover the lime, an improved filtration rate is obtained. In addition, washing of the lime cake to remove impurities such as sodium chloride is easily accomplished because of the ease of separating wash water in the presence of the hemi-basic calcium hypochlorite crystals.

Abstract: A diaphragm for use in the electrolysis of alkali metal chloride brines in electrolytic diaphragm cells is comprised of a support fabric impregnated with a non-fibrilic active component containing silica where the porous diaphragm has a permeability to alkali metal chloride brines of from about 100 to about 300 milliliters per minute per square meter of diaphragm at a head level difference in the cell of from about 0.1 to about 20 inches of the alkali metal chloride brines. The active component containing silica is employed in concentrations of from about 10 to about 75 milligrams per square centimeter of support fabric.Suitable silica-containing materials include sand, colloidal silica, alkali metal silicates, alkaline earth metal silicates, aluminum silicates, as well as minerals such as sepiolites, meerschaums, attapulgites, montmorillonites and bentonites.Support fabrics include, for example, felt fabrics produced from thermoplastics such as polyolefins or polyarylene sulfides.

Abstract: A process is disclosed for reducing the available chlorine content of aqueous waste streams produced in chemical plants, especially calcium hypochlorite plants, in order to permit further purification treatment in waste purification systems which employ activated carbon. The available chlorine content is reduced by chlorinating the impure stream at a temperature in the range from about 80.degree. to 100.degree. C. at a pH in the range from about 5.5 to about 8.5. In order to avoid excessive reactor boilover, close control of these conditions is required. In addition the reaction is time dependent and the holdup time in the reactor and a subsequent hold tank ranges from about 0.5 to about 4 hours. During this reaction the available chlorine forms the corresponding chlorate in the aqueous solution which may be passed through the activated carbon bed without adversely affecting the bed operation.

Abstract: An improved method and apparatus for adjusting the space between an adjustable anode and a cathode in an electrolytic cell wherein current measurements and voltage measurements are obtained for conductors to the anode sets and compared with predetermined standards for the same conductors and anode sets. Measurement of deviation from the predetermined standards are used to determine the direction of anode adjustment. A digital computer operably connected to motor drive means adapted to raise or lower anode sets upon appropriate electric signals from the computer is a preferred embodiment of this invention.In a preferred embodiment, potential incipient short circuits are detected and avoided by the improvement which comprises:(a) obtaining the difference between two successive current signals for a selected conductor and doubling the difference to obtain a total current difference, .DELTA..sub.

Abstract: A process is described in which granular calcium hypochlorite particles are encapsulated with a plurality of layers of an inorganic salt other than calcium hypochlorite. In this process granular calcium hypochlorite particles are placed in a moving bed and a portion of the moving bed is lifted to the upper part of a distributing zone and released to fall downwardly through the distributing zone to the moving bed. An aqueous medium of the inorganic salt is sprayed onto the falling particles at a temperature sufficiently high to simultaneously evaporate and remove water from the aqueous medium and to provide a coating of a plurality of layers of inorganic salt in solid form on each calcium hypochlorite particle.

Abstract: Asbestos diaphragms in commercial cells for the electrolysis of brines are treated with a dispersion of an alkaline earth metal-containing silicate. Deposition of the dispersion within the diaphragm results in a decrease in hydrogen concentration in chlorine gas produced as well as an increase in current efficiency.

Abstract: A diaphragm for use in the electrolysis of alkali metal chloride solutions in electrolytic diaphragm cells is comprised of a mixture of an electrically non-conducting, non-swelling support material impregnated with a mixture of sand and a synthetic thermoplastic polymeric binding agent. The diaphragms may include a lubricant, a wetting agent or an additive such as alumina, inorganic phosphates, lithium salts, lime, magnesia or inorganic magnesium salts. The diaphragms of the present invention have increased chemical and dimensional stability, a long operational life and are non-polluting.

Abstract: A diaphragm for use in the electrolysis of alkali metal chloride solutions in electrolytic diaphragm cells is comprised of a mixture of sand and a polyolefin thermoplastic polymeric binding agent. The diaphragms may include a support material and an additive such as a lubricant. The diaphragms of the present invention have increased stability, a long operational life and are non-polluting.

Abstract: A diaphragm for use in the electrolysis of alkali metal chloride solutions in electrolytic diaphragm cells is comprised of a mixture of sand and a thermoplastic polymeric binding agent comprised of a mixture of a polyarylene sulfide and a polyolefin compound. The diaphragms may include a support material and an additive such as a lubricant. The diaphragms of the present invention have increased stability, a long operational life and are non-polluting.

Abstract: A method and composition are described for the decomposition of sodium-mercury amalgam in a reactor containing solid packing particles to form hydrogen, sodium hydroxide, and denuded mercury. The novel packing particles are comprised of a heterogeneous solid mixture of a matrix of a thermally stable polymer having embedded therein discrete particles of a surface active composition. Suitable thermally stable polymers include polyphenylene sulfide and suitable surface active compositions include carbon, iron, nickel, cobalt, vanadium, and molybdenum. The proportion of polymer in the packing generally ranges from about 20 to about 80 percent by volume. Preferably, the matrix is prepared in porous form which may also be coated with a surface active metal.

Abstract: A diaphragm for use in the electrolysis of alkali metal chloride brines in electrolytic diaphragm cells is comprised of a support fabric impregnated with a non-fibrilic active component containing silica. The support fabric has a non-continuous coating of an electroconductive metal on one side of the fabric. Suitable electroconductive metals include nickel, nickel alloys, gold, gold alloys, platinum group metals, platinum group metal alloys, and mixtures thereof.The diaphragms are physically and chemically stable, provide reduced cell voltages during operation of the cell and have increased operational life.

Abstract: Polychloroisocyanurate products are produced in a continuous process which reacts a cyanuric acid component with a chlorinating agent in a reaction mixture to which a purge gas is fed to remove in an effluent gas, any nitrogen trichloride produced along with other by-products. The effluent gas is fed to a gas analyzer such as a gas chromatograph which determines the concentration of NCl.sub.3 present and compares it with a predetermined upper limit. If this upper limit is equalled or exceeded, the gas analyzer activates means to flood the reaction mixture with purge gas to prevent explosive amounts of nitrogen trichloride from being present in the reaction mixture. The gas analyzer may also control the feed rate of the cyanuric acid component and the chlorinating agent.The pH of the reaction mixture is also continuously measured in a pH analyzer having means to control the flow rate of the purge gas and reactants should the predetermined pH limits for the reaction be attained or exceeded.

Abstract: An improved method and apparatus for adjusting the space between an adjustable anode and a cathode in an electrolytic cell wherein current measurements and voltage measurements are obtained for conductors to the anode sets and compared with predetermined standards for the same conductors and anode sets. Measurement of deviation from the predetermined standards are used to determine the direction of anode adjustment. A digital computer operably connected to motor drive means adapted to raise or lower anode sets upon appropriate electric signals from the computer is a preferred embodiment of this invention.

Abstract: A membrane cell for the electrolysis of aqueous salt solutions is provided in which the foraminous metal anode is enclosed in the membrane. Spacing means are provided to separate the portions coated with an electrocatalytically active material from the membrane. The spacing means may be a nonconducting material or the coated surface of the anode may be faced away from the membrane to permit the anode structure to serve as the spacing means. To provide a low cell voltage and permit efficient hydrogen gas release from the caustic solution, the cathode is spaced apart from the membrane.

Abstract: Mercury and caustic values are recovered from caustic sludges in a process which comprises intermixing the caustic sludge with a liquid under pressure or agitation to produce a caustic slurry which is separated into a caustic liquor, metallic mercury and a remaining sludge which is suitable for roasting in a retort to recover better than 99 percent of the mercury in the sludge.The process recovers valuable mercury and caustic materials and eliminates pollution of natural resources which was formerly caused when these sludges were disposed of in landfill operations. In addition, the process reduces potential hazards to personnel handling the caustic sludges and requires no addition of chemicals which produce undesirable by-products and add to the cost of the recovery process.

Abstract: Decomposition of chloroisocyanurates such as trichloroisocyanuric acid or alkali metal dichloroisocyanurates is inhibited by the presence of alkaline earth metal sulfates. The sulfates may be used in compositions with a solid chloroisocyanurate or they may be added separately, for example, to packages containing the chloroisocyanurate.