Abstract: A method and apparatus for the generation, use, and disposal of chlorine dioxide is disclosed. A solid sodium chlorite composition having impurities, at least one of which is sodium hydroxide, is contacted with an agent to consume essentially all of the sodium hydroxide. Chlorine dioxide gas is then generated by contacting the resultant composition with chlorine in a humidified inert carrier gas. The resultant chlorine dioxide gas mixture may then be treated to remove chlorine gas present therein by contacting the same with sodalime in particulate form. After using the chlorine dioxide gas mixture in the desired manner, chlorine dioxide present in the spent effluent gas may be substantially removed via the introduction of the effluent gas into an aqueous solution of sodium thiosulfate having a sufficient amount of an inorganic base to maintain the alkalinity of the solution during consumption of thiosulfate by chlorine dioxide.

Abstract: A process for the generation of chlorine dioxide from an alkali metal chlorate is provided that employs a waste sulphuric acid containing oxidizable organic material. Alkylation waste sulphuric acid from petroleum refining is particularly useful in this process. Conventional chlorate reducing agents used in the generation of chlorine dioxide can be partially or completely replaced by the organic material contained in the alkylation waste acid.

Abstract: A two-stage process for treating anode slimes and other residues containing a substantial amount of nickel without significant dissolution of silver and/or selenium in a single autoclave is disclosed. The process comprises, in a first stage, leaching the anode slimes at 15-30% solids in dilute sulphuric acid at a pressure between 4.0 and 5.5 bars and a temperature between 155.degree. C. to 170.degree. C. in the absence of oxygen to solubilize nickel, and in a second stage, without performing a solid liquid separation, leaching the remaining solids at a pressure between 2 and 3.5, preferably about 2.8 bars and a temperature between 110.degree. and 140.degree. C., preferably about 120.degree. C. with oxygen sparging such that the final sulphuric acid concentration is not less than 50 gpl to solubilize copper and tellurium.

Abstract: The invention provides a process for the selective absorption of chlorine from CO.sub.2 -containing off-gases, which comprises washing the off-gases with an aqueous solution which contains 0.1-10% by weight of NaHCO.sub.3 and 0.01-5% by weight of NaHSO.sub.3.

Abstract: A process for producing a peroxoniobic acid sol which comprises: adding a strong acid, hydrogen peroxide and water to at least one niobium compound selected from the group consisting of niobium hydroxide, niobium oxide and niobium pentachloride to provide an aqueous solution of peroxoniobic acid; and then maintaining the aqueous solution at a temperature of 5.degree.-50.degree. C.

Abstract: A process for producing lithium hypochlorite which admixes an aqueous hypochlorous acid solution, having a concentration of 35 percent or greater by weight of HOCl, with an aqueous slurry of lithium hydroxide at a temperature in the range of from about 0.degree. to about 20.degree. to produce a solution of substantially pure lithium hypochlorite. The lithium hypochlorite solutions produced can be dried directly or concentrated by cooling. The solid lithium hypochlorite produced is a highly pure source of available chlorine.

Abstract: A vapor stream from a sand chlorinator containing principally zirconium tetrachloride, hafnium tetrachloride and silicon tetrachloride contaminated with ferric chloride is purified by cooling the vapor to a temperature of about 335.degree. C. to about 600.degree. C. The cooled vapors flow through a gaseous diffusion separative barrier where a silicon tetrachloride vapor stream contaminated with metal chlorides flows from the separative barrier as a "fast" stream; ferric chloride is adsorbed by the separative barrier; and a vapor stream principally containing zirconium tetrachloride, hafnium tetrachloride and silicon tetrachloride is screened by the separative barrier.

Abstract: A process for manufacturing high purity anhydrous hydrogen fluoride (HF) having low levels of oxidizable impurities by electrolytically oxidizing the impurities. Specifically, trivalent arsenic impurity in the anhydrous hydrogen fluoride is oxidized to a non-volatile pentavalent arsenic compound. The resultant mixture is distilled to recover high purity anhydrous hydrogen fluoride with low levels of arsenic impurity.

Abstract: Waste gases containing ClF.sub.3 are treated by bringing them into contact with iron oxide substantially composed of a ferric oxide (Fe.sub.2 O.sub.3) at a linear velocity of about 10-200 cm/min at ordinary temperatures, or further into contact with an alkali agent at the same linear velocity and temperatures as the above, whereby the content of ClF.sub.3 can be reduced below the permissible level despite simultaneous emission of acidic gases, and yet which is capable of removing the concomitant acidic gases in an effective manner.

Abstract: A process for the production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, mineral acid and a reducing agent in such proportions that chlorine dioxide is produced in a reaction medium which is maintained at a temperature of from about 50.degree. C. to about 100.degree. C. and at an acidity within a range of from about 2 to about 11N and which is subjected to subatmospheric pressure sufficient for evaporating water. A mixture of chlorine dioxide and water vapor is withdrawn from an evaporation zone in the reaction vessel, and alkali metal sulfate is precipitated in a crystallization zone in the reaction vessel. Straight chained alcohols with the formula CH.sub.2 OH(CHOH).sub.n CH.sub.2 OH where n=0-5, are used as reducing agents. Preferred reducing agents consist of glycol or glycerol. The reaction may also be performed in the presence of a catalyst.

Abstract: A calcium hypochlorite composition consists essentially of at least 75 percent by weight of Ca(OCl).sub.2, from about 6 to about 14 percent by weight of water, and less than 1.5 percent by weight of an alkali metal chloride. The novel composition provides increased amounts of sanitizing and disinfecting to, for example, water bodies while remaining safe with respect to thermal decomposition. Further, the composition reduces the rate of chlorine evolution during storage.

Abstract: A process for the production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, mineral acid and a reducing agent in such proportions that chlorine dioxide is produced in a reaction medium which is maintained at a temperature of from about 50.degree. C. to about 100.degree. C. and at an acidity within a range of from about 5N to about 11N. The reaction medium is subjected to subatmospheric pressure sufficient for evaporating water, a mixture of chlorine dioxide, oxgen and water vapour being withdrawn from an evaporation zone in the reaction vessel, and alkali metal sulfate being precipitated in a crystallization zone in the reaction vessel. As the reducing agent hydrogen peroxide is used.

Abstract: A method of producing an anhydrous niobium or tantalum pentafluoride involving reacting the corresponding pentoxide or oxyhalide with an excess of anhydrous hydrogen fluoride in the presence of a sufficient dehydrating agent (e.g., COCl.sub.2, SOCl.sub.2 or SO.sub.2 Cl.sub.2) to react with any water formed. Such a process is useful to produce a catalyticallyactive anhydrous niobium or tantalum pentafluoride in essentially a single liquid phase reaction step.

Abstract: A process for the production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, mineral acid and a reducing agent in such proportions that chlorine dioxide is produced in a reaction medium which is maintained at a temperature of from about 50.degree. C. to about 100.degree. C. and at an acidity within a range of from about 2 to about 5N. The reaction medium is subjected to subatmospheric pressure sufficient for evaporating water, a mixture of chlorine dioxide, oxygen and water vapor being withdrawn from an evaporation zone in the reaction vessel, and alkali metal sulfate being precipitated in a crystallization zone in the reaction vessel. As the reducing agent hydrogen peroxide is used.

Abstract: The present invention provides a process for the conversion of hazardous hexafluoroarsenic acid or any salt thereof to arsenic acid or salt thereof which can be rendered nonhazardous. In particular, the hexafluoroarsenic acid or salt is converted to arsenic acid or salt which can be converted to a water insoluble salt. Known insolubilization and stabilization technology then renders the material nonhazardous.The present process involves converting hexafluoroarsenic acid or salt thereof contained in an aqueous mixture to arsenic acid or salt thereof.

Abstract: A method and apparatus are provided for treatment of acid fumes to reduce the acid content of the fumes to meet the stringent environmental requirements. The acid fumes are treated in a packed zone containing, as the packing materials, polyester resins treated with aluminum sulfate crystals.

Abstract: Potassium chloride crystals of larger and/or more regular size are produced by conducting the crystallization in the presence of a small amount of a branched C.sub.12 monoalkylated diphenyl ether sulfonate or a linear C.sub.6 alkylated diphenylether sulfonate.

Abstract: A process and apparatus utilizing the process of the present invention are provided to produce a fast dissolving, thermally sensitive granular product. The process employs a fluidized spray dryer having a fluidized bed of granular particles into which recycled off-sized product is fed after being agglomerated to adjust particle size. The spray dryer optionally can employ a second nozzle positioned above the fluidized bed. The process can be employed in the production of calcium hypochlorite water sanitizing chemical wherein the chlorine is supplied from a hypochlorous acid reactor and lime hypochlorinator.

Abstract: An improved process for generating an elemental halogen selected from chlorine, bromine or iodine, from a corresponding hydrogen halide by absorbing a molten salt mixture, which includes sulfur, alkali metals and oxygen with a sulfur to metal molar ratio between 0.9 and 1.1 and includes a dissolved oxygen compound capable of reacting with hydrogen halide to produce elemental halogen, into a porous, relatively inert substrate to produce a substrate-supported salt mixture. Thereafter, the substrate-supported salt mixture is contacted (stage 1) with a hydrogen halide while maintaining the substrate-supported salt mixture during the contacting at an elevated temperature sufficient to sustain a reaction between the oxygen compound and the hydrogen halide to produce a gaseous elemental halogen product. This is followed by purging the substrate-supported salt mixture with steam (stage 2) thereby recovering any unreacted hydrogen halide and additional elemental halogen for recycle to stage 1.

Abstract: A method is provided for reducing the sulfur content of exhaust (flue) gas from a combustion installation manufacturing process, or chemical process comprising the step of injecting dry powder alkali hydrate sorbent directly into intermediate temperature (800.degree.-1200.degree. F.) combustion/process gases. The alkali hydrate sorbent reacts rapidly with the sulfur-containing gases in this temperature regime to produce primarily alkali sulfites. The unreacted portion of the sorbent largely remains in the form of an alkali hydrate and may react further with residual sulfur, especially in the presence of water, at lower temperatures. A novel combustion chamber is also provided having an injection means for injecting alkali hydrate sorbent into a combustion volume where the temperature is in the range of 800.degree.-1200.degree. F., to cause a predetermined reaction of the alkali hydrate sorbent with SO.sub.