Abstract: The combination of a passive dosing dispenser, of the type having a reservoir containing a cake of active ingredients which are depleted as water is routed through the dispenser, and an improved hypochlorite cake for use therein. The improved hypochlorite cake provides water-soluble hypochlorites, and additionally contains materials capable of forming a water-insoluble matrix from which hypochlorite salts may be leached out by the water in the reservoir. The size of the cake desirably increases somewhat while the dispenser is in use so that the mass of aqueous hypochlorite which may be poured from the reservoir of the dispenser remains constant or slightly decreases as the active ingredients are used up.

Abstract: Rounded granular calcium hypochlorite comprised of a core of calcium hypochlorite encapsulated with a plurality of rounded layers of calcium hypochlorite, wherein the core of each particle generally has a diameter which ranges from about 200 to about 2,000 microns and the novel coated granules have a diameter ranging from about 400 to about 5,000 microns. Each layer is formed from an aqueous slurry of calcium hypochlorite which contains a high percentage of soluble inorganic salts as well as calcium hypochlorite. These soluble salts impart a high degree of cohesive bonding as each layer is formed and result in rounded granules of higher density and improved dust resistance.

Abstract: A process for the manufacture of neutral calcium hypochlorite wherein (a) a dibasic calcium hypochlorite is manufactured by adding lime to the recycled mother liquor obtained in at least one of steps (b), (c), (d) and (e), (b) the dibasic substance is separated from its mother liquor, (c) the separated dibasic substance and added caustic soda are chlorinated simultaneously, in a suspension of preformed crystals of neutral calcium hypochlorite and sodium chloride, (d) the crystalline calcium hypochlorite is separated from the crystalline sodium chloride and (e) the resulting neutral calcium hypochlorite is treated and dried in a conventional manner, and, the resulting sodium chloride is crystallized and purified by washing with the mother liquor from step (b). A neutral calcium hypochlorite is produced having a high content of active chlorine and with substantial reduction of environmental pollution by discharge of effluent.

Abstract: A dihydrate of calcium hypochlorite of a prismatic crystal shape in which the lengths of axes a, b and c thereof are in the ratios satisfying the following formulas (1), (2) and (3):0.5.ltoreq.b/a.ltoreq.2.0 (1)c/a.gtoreq.1.5 (2)c.gtoreq.5.mu. (3)and a method for the manufacture of the prismatic dihydrate. Further a method for the manufacture of a coarse dihydrate of calcium hypochlorite carried out by using the prismatic dihydrate of calcium hypochlorite as seed crystal.

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 method of forming a chlorine tablet for combatting bacterial and algaecidal contamination of swimming pools and the like, which includes the step of pressing a mixture of calcium hypochlorite and chloride of lime, together with a minor proportion of zinc stearate as a tabletting lubricant, into a tablet. The invention further relates to such a tablet.

Abstract: Calcium hypochlorite useful as a commercial sanitizing agent and swimming pool disinfectant is produced by a process wherein calcium hydroxide and organic hypochlorite are reacted in a first reaction zone to produce calcium hypochlorite. The portion of the calcium hydroxide remaining unreacted is recovered along with product calcium hypochlorite in a mixture of solids.In a second reaction zone, an aqueous solution of sodium hydroxide is reacted with an organic hypochlorite to form an aqueous phase containing sodium hypochlorite and an organic phase. The aqueous phase is separated from the organic phase.Chlorine is reacted with the mixture of solids of the first reaction zone and the aqueous phase of the second reaction zone in a third reaction zone to produce an aqueous slurry of calcium hypochlorite particles. The calcium hypochlorite particles are thereafter recovered and dried in granular form.

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 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: A granular, heterogeneous calcium hypochlorite composition comprising a mixture of a substantially anhydrated granular component and a hydrated granular component keeping the crystallization water of from 2 to 3 moles water per mole of Ca(OCl).sub.2 in the form of Ca(OCl).sub.2.3H.sub.2 O has an improved stability and safety, and said composition is suitable for preparing break-resistant, good-dissoluble calcium hypochlorite tablets.

Abstract: A particulate detergent composition containing dibasic magnesium hypochlorite having a specific small particle size as the bleaching agent.

Abstract: The present invention describes a solid calcium hypochlorite composition comprising calcium hypochlorite and about 0.5% to about 50% by weight of substantially water-insoluble and unchlorinated magnesium compounds, said magnesium compounds being derived from impure hydrated lime. Furthermore, the present invention describes a process for making this composition, which is an improvement in the known process for the manufacture of a solid calcium hypochlorite composition wherein an aqueous slurry comprising a hydrated lime, a mixture of hydrated lime and at least one alkali metal hydroxide, or a mixture of hydrated lime and at least one alkali metal hypochlorite, is chlorinated to form an aqueous chlorinated slurry containing calcium hypochlorite and further processing said chlorinated slurry to recover a solid calcium hypochlorite composition.

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 process is described for recovering calcium hypochlorite values from the filter media employed in the filtration of calcium hypochlorite slurries. Deposits of Ca(OCl).sub.2 along with insoluble materials adhering to the filter media are washed with an aqueous solution of calcium hypochlorite to form a slurry of calcium hypochlorite solids. Water is used to wash the filter media to dissolve any remaining Ca(OCl).sub.2 and form a solution of calcium hypochlorite. The slurry and solution are then admixed to provide a solution of calcium hypochlorite whose concentration is controlled within the range of from about 45 to about 215 grams per liter of Ca(OCl).sub.2. This solution is employed in the production of calcium hypochlorite and is recycled to the washing step.

Abstract: An aqueous hypochlorite solution containing a stabilizing amount of periodate ions, preferably an amount in the range 0.05 to 1000 parts per million (ppm) by weight based on the volume of the solution, the solution optionally containing silicate ions.

Abstract: Safety-calcium hypochlorite composition containing 16% by weight to about 22% by weight of water and at least an amount of calcium hypochlorite corresponding to 60% by weight of active chlorine content on a dry basis on the composition, wherein active chlorine content is a number of percentage of twice the weight of chlorine of calcium hypochlorite divided by weight of a mixture.

Abstract: A process is described in which granular calcium hypochlorite particles are encapsulated with at least one layer of a hydrated low melting inorgnaic 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: Novel compositions comprising calcium hypochlorite and a hydrazide of a monocarboxylic acid containing from about 10 to about 24 carbon atoms have been produced. The compositions provide accurately controlled concentrations of available chlorine to bodies of water such as swimming pools by reducing the solubility of the calcium hypochlorite.

Abstract: Hypochlorite is produced by mixing chlorine and a strong alkali solution within a completely closed region filled with solution to eliminate the presence of any air pockets, thereby assuring that the gaseous chlorine will not escape from the solution during the mixing process. In carrying out the mixing step, the alkali solution and chlorine are introduced through relatively closely-spaced small streams into an enlarged chamber so that, effectively, mixing occurs by small amounts at the point of introduction of the two streams, instead of simply introducing a small amount of chlorine into a large volume of alkali solution. Mixing is further enhanced by the fact that the two streams are introduced tangentially into the chamber at diametrically opposed locations so that they swirl upwardly through the chamber in laminar flow relationship.

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 in a fluidized bed. 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 particles is removed from the spraying zone and further processed, if desired. In one embodiment, the coated particles with or without sizing are further dried to produce granular particles having the desired moisture content.

Abstract: In the known process of preparing a slurry of calcium hypochlorite by reaction of chlorine with a slurry of calcium hydroxide and sodium hydroxide, we provide the improvement consisting of continuously pumping into a first stirred reactor an aqueous slurry of calcium hydroxide and sodium hydroxide optionally partially chlorinated and simultaneously passing chlorine gas into the reaction mixture at such a rate that the redox potential is in the range from 650-850 mV and allowing the contents of the first reactor to overflow continuously into a second stirred reactor and simultaneously passing chlorine gas into the second reactor at such a rate that the redox potential is in the range from 750-950 mV and allowing the contents of the second reactor to overflow and be removed as product; the temperature of the contents of the first and second reactor are independently maintained at a temperature in the range 15.degree. to 35.degree.C.

Abstract: A continuous process for the manufacture of calcium hypochlorite in which an aqueous slurry of lime and sodium hypochlorite is chlorinated in a mixing zone to form a sodium chloride solution containing large crystals of calcium hypochlorite which are readily separated and dried. The resulting solution containing some dissolved calcium hypochlorite is reacted with an alkali metal hydroxide to precipitate lime, which is separated and recycled to the mixing zone slurry. The lime-free solution may be used as bleach liquor or processed to precipitate solid salt useful in the preparation of brine. The remaining solution is recycled to the mixing zone slurry. Purification of fresh lime is also disclosed.The process provides an improved separation of calcium hypochlorite and sodium chloride, and recycles all solutions to minimize pollution of water resources.

Abstract: Calcium hypochlorite compositions, suitable for bleaching and sanitation uses, are provided which have improved resistence to exothermic decomposition. These novel compositions are granules comprised of a core of calcium hypochlorite encapsulated with a coating comprised of a mixture of calcium hypochlorite dihydrate and a water soluble inorganic salt which is non-reactive with and stable in contact with calcium hypochlorite. Generally the coating comprises from about 5 to about 60 percent by weight of each granule and the proportion of water soluble salt ranges from about 0.1 to about 15 percent by weight of each granule. The granular product also resists dusting and caking and has improved retention of its available chlorine on storage.

Abstract: A continuous cyclic process for production of calcium hypochlorite wherein an aqueous solution saturated with calcium hypochlorite and sodium chloride is chlorinated by using chlorine gas to produce sodium chloride crystals and an aqueous chlorinated reaction mixture, the formed sodium chloride crystals being then separated from said aqueous chlorinated reaction mixture. First sodium hydroxide is added to the foregoing aqueous solution which solution also contains calcium hypochlorite and sodium chloride in the crystal phase. Then calcium hydroxide and sodium hydroxide is further added to the aqueous chlorinated reaction mixture remaining after separation of said crystals therefrom. This mixture containing calcium hydroxide and sodium hydroxide is again chlorinated with chlorine gas to produce a slurry containing mainly sodium chloride crystals, calcium hypochlorite crystals and a mother liquor saturated with calcium hypochlorite and sodium chloride.