Abstract: A process for preparing hypochlorous acid in a sweep reactor is described in which gaseous chlorine is passed rapidly across the surface of an agitated aqueous solution of alkali metal hydroxide at a reduced temperature. The resulting gaseous product mixture of hypochlorous acid, chlorine monoxide, and unreacted chlorine is conveyed from the reactor to a suitable scrubber to produce an aqueous hypochlorous acid solution.The aqueous reaction product of the sweep reactor is a suspension of alkali metal chloride in alkali metal hypochlorite, which is withdrawn and filtered to separate the solid. The clarified aqueous solution of alkali metal hypochlorite is reacted with the aqueous hypochlorous acid solution from the scrubber, chlorine and lime to form an aqueous slurry of calcium hypochlorite. This slurry may be granulated by the spray graining technique, for example, to produce strong rounded granules of calcium hypochlorite.

Abstract: A process for reducing the radioactive contamination in waste product gypsum in which waste product gypsum is reacted with a dilute sulfuric acid containing barium sulfate to form an acid slurry at an elevated temperature, the slurry is preferably cooled, the acid component is separated from the solid, and the resulting solid is separated into a fine fraction and a coarse fraction. The fine fraction predominates in barium sulfate and radioactive contamination. The coarse fraction predominates in a purified gypsum product of reduced radioactive contamination.

Abstract: A process is described in which granular calcium hypochlorite particles are encapsulated with at least one layer of a hydrated low melting inorganic salt. In this process granular calcium hypochlorite particles are lifted from a moving bed to the upper part of a distribution zone and the lifted particles are released to fall downwardly through the upper portion to the moving bed. A molten hydrated low melting inorganic salt is sprayed onto the falling particles above the moving bed, and the coated particles are cooled to provide at least one solid outer layer of said low melting hydrated inorganic salt.

Abstract: A process for preparing hypochlorous acid is described in which gaseous chlorine is reacted with an aqueous solution of alkali metal hydroxide in a finely divided mist form at an elevated temperature sufficient to prevent condensation of the gaseous product. Gaseous hypochlorous acid product is immediately separated from the resulting solid alkali metal chloride as it is formed and is then scrubbed with water to form an aqueous hypochlorous acid solution. This solution may be reacted with lime to produce calcium hypochlorite.

Abstract: Alkali metal dichloroisocyanurate compositions having improved resistance to thermal decomposition comprise an alkali metal dichloroisocyanurate and a proportion of an alkali metal chloride where the proportion is from about 6 to about 14 percent by weight of the alkali metal dichloroisocyanurate. Water may be used to replace part of the alkali metal chloride proportion.The compositions are suitable for use in bleaching and sanitizing applications.

Abstract: Electrolysis of alkali metal chloride solutions to produce chlorine and alkali metal hydroxides is accomplished in a cell comprising an anode compartment, a cathode compartment, a cation permeable divider separating the anode compartment from the cathode compartment, where the anode compartment contains an anode separator. The anode separator is comprised of a porous plate of a valve metal having an electrochemically active coating on the face, and an electrochemically non-active barrier layer on the back and a portion of the interior. The anode separator is positioned in the anode compartment so that the back of the anode separator is spaced apart from the cation permeable divider. An alkaline brine zone is formed between the anode separator and the cation permeable divider which increases the service life of the cation permeable divider.

Abstract: A process for recovering chlorine values from an aqueous solution of a chloroisocyanuric acid compound is disclosed. After reacting a mineral acid with the aqueous solution to form an acidified reaction mixture containing dissolved chlorine, the reaction mixture is fed to a stripping column which employs an inert gas to remove the dissolved chlorine. The stripping column is maintained to provide a continuous liquid phase and a non-continuous gas phase. Chlorine gas is readily recovered in a vessel such as a scrubber. Cyanuric acid may be subsequently recovered from the chlorine-depleted solution.

Abstract: An electrode is described which is comprised of an electroconductive substrate having an exterior surface of perovskite of the empirical formulaA A' B O.sub.3 (I)a. wherein A is lanthanum,B. wherein A' is an alkaline earth metal selected from the group consisting of calcium, strontium, barium, and mixtures thereof,C. wherein B is a transition metal selected from the group consisting of cobalt, chromium, tungsten, molybdenum, manganese, iron, nickel, rhenium, uranium, and mixtures thereof,D. wherein the atomic ratio of A:A' is in the range from about 0.05:1 to about 0.95:1,E. wherein the valence of A + A' + B = 6,f. wherein said electrode has a resistivity preferably less than about 10 milliohm-centimeters.sup.-1, andG. wherein said perovskite is substantially insoluble in the electrolyte contacting said electrode under typical conditions of electrolysis.

Abstract: Electrolysis of alkali metal chloride solutions to produce chlorine and alkali metal hydroxides is accomplished in a cell comprising an anode compartment, a cathode compartment and an anode separator which divides the anode compartment from the cathode compartment. The anode separator is comprised of a porous plate of a valve metal having an electrochemically active coating on the face, and an electrochemically non-active coating on the back and a portion of the interior. The electrochemically non-active barrier layer may include resinous materials, for example, polyarylene compounds or polyolefin compounds.The anode separator provides improved gas separation properties, eliminates the need for a separate diaphragm or membrane and enables the cell to operate with reduced power requirements.

Abstract: A method is provided for renewing the permeability of a porous diaphragm comprised of a synthetic fluorocarbon resin having ion exchange properties which comprises feeding an alkaline solution of an alkali metal chloride having a pH of from about 9 to about 12 to the anode compartment. A first portion of the alkaline brine passes through the porous diaphragm and a second portion contacts the porous diaphragm and is then removed from the anode compartment.

Abstract: Granular calcium hypochlorite particles having a core of calcium hypochlorite encapsulated in a plurality of layers of calcium hypochlorite are produced from an aqueous slurry of calcium hypochlorite by spraying a pumpable and sprayable slurry of calcium hypochlorite particles onto suspended particles of solid calcium hypochlorite above a moving bed of said particles. The solid particles coated with the slurry are heated to simultaneously evaporate and remove water from the slurry whereby said particles are coated with a layer of solid calcium hypochlorite.A portion of the moving bed of coated articles is removed from the spraying zone and further processed, if desired. In one embodiment the coated articles, with or without sizing, are dried to produce granular particles having the desired moisture content.

Abstract: Diluted sulfuric acid used in the production of wet process phosphoric acid is obtained by the admixing of gypsum-containing waste water with concentrated sulfuric acid and subsequently cooling in a liquid-to-liquid heat exchanger. By maintaining the concentration of the diluted acid at from about 65 to 80% H.sub.2 SO.sub.4, harmful formation of scale in the heat exchanger is prevented. The process permits the recovery of P.sub.2 O.sub.5 values from gypsum-containing waste waters and does not require expensive dilution tanks or flash coolers.

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: Calcium hypochlorite compositions useful as bleaching agents and disinfectants are produced by the reaction of solid granular quicklime with a gaseous mixture of dichlorine monoxide and an inert gas. The process takes place in the absence of a solvent and produces dry, free-flowing Ca(OCl).sub.2 compositions.

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 the 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: An electrolytic cell employing a hydraulically impermeable membrane having a spacing means interposed between the anode and the membrane, is operated by providing a positive pressure differential between the cathode compartment and the anode compartment. The pressure differential is sufficient to maintain contact between the spacer and the membrane to provide uniform spacing between the anode and the membrane. In addition, this process provides sufficient spacing between the membrane and the cathode to provide efficient release of any gas formed and to prevent gas blinding at the cathode. Employing the positive pressure differential enables the cell to be operated at reduced energy costs when producing, for example, concentrated solutions of sodium hydroxide by careful control of the spacing between the membrane and the electrodes.

Abstract: An improved process is described for preparing defluorinated phosphate rock from fluorine-containing phosphate rock which contains acid insoluble impurities in excess of about 6 percent by weight. The improvement is particularly useful in the fluidized bed technique for preparing defluorinated phosphate rock wherein fluorine-containing phosphate rock, a sodium compound such as sodium carbonate, phosphoric acid and water are admixed to form granules. The resulting granules are dried and heated in a fluidized bed calciner at a temperature within the range of from about 980.degree. to about 1,350.degree. C to evolve sufficient fluorine to produce defluorinated phosphate rock graules having less than 1 part of fluorine per 100 parts of phosphorus by weight. The resulting defluorinated granules are colled and stored for use as an animal feed which contains at least 18 percent by weight of phosphorus.

Abstract: Aqueous solutions containing mixtures of sodium dithionite and sodium sulfite having concentrations of greater than 13 percent by weight of Na.sub.2 S.sub.2 O.sub.4 are stabilized by adding potassium hydroxide in an amount which is sufficient to provide a residual of from about 1 to about 12 grams per liter of solution. These solutions can be stored at temperatures of from about 0.degree. to about 15.degree. C. without crystallization taking place.

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: Alkali metal salts of dichloroisocyanuric acid are produced by the reaction of a monoalkali metal cyanurate with an alkali metal hypochlorite and chlorine in an aqueous medium while maintaining the pH of the reaction mixture in the range of from about 6.0 to about 7.5 and recovering the solid alkali metal dichloroisocyanurate produced thereby.The products are useful as bleaching or sanitizing agents.