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: 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: 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 rapid and effective removal of iodine, organic iodine compounds with a small number of carbon atoms or mixture thereof from gases and/or vapors, comprising passing said gas or vapor through an adsorbent bed containing a silver-lead-exchanged zeolite X.

Abstract: A process for the removal of chlorine from off-gases which continuously or sporadically contain small amounts of chlorine by scrubbing the off-gases with a ferrous chloride-containing aqueous solution in a scrubbing system. The solution used is obtained by dissolving a solids mixture which results from the chlorination of a titaniferous and ferriferous feedstock material and which contains essentially ferrous chloride. This solution is used in particular for the scrubbing of off-gases formed in the production of titanium dioxide by the chlorination of titaniferous and ferriferous feedstock material, thus generating titanium tetrachloride and ferrous chloride, and by the reaction of the titanium tetrachloride with oxygen-containing gases. It is preferably the solids mixture separated in this process from the chlorination mixture in a condensation step that is dissolved in the process of the invention, and at least part of the resulting solution is used for the scrubbing of the off-gases.

Abstract: Low-level fluorine concentrations are removed from gases by conducting a gas stream containing fluorine over an alumina treated with chromium oxide material, thereby effectively eliminating fluorine from the gas while preventing the formation of toxic oxygen difluoride by-product.

Abstract: The concentration of molecular fluorine in a mixed gas such as an excimer laser gas can be determined easily, quickly and accurately by passing the mixed gas through a column packed with an alakli metal or alkaline earth metal compound which has no halogen atom and reacts with fluorine to form a solid fluoride together with molecular oxygen and/or carbon dioxide and measuring the concentration of oxygen or carbon dioxide in the fluorine-free gas flowed out of the packed column. If the mixed gas initially contains molecular oxygen or carbon dioxide, its concentration is measured separately after fixing fluorine in another column packed with an element which forms a fluoride. This analyzing method can be used in a feedback control system for controlling the concentration of fluorine in an excimer laser gas during operation of the laser to thereby stabilize the laser output power.

Abstract: Air contaminated with chemical and biological pollutants is purified by treating chemically and electrochemically in a closed system minimizing the generation of by-products for disposal. Pollutants are treated in a scrubber zone with a scrubber liquid-electrolyte comprising pollutant degrading metal ions or complexed with inert metal ions and degraded either in an electrolyzer zone or in both the scrubber and electrolyzer zones where spent scrubber liquid-electrolyte is regenerated for further cleaning.

Abstract: A process for the removal of chlorine from reducing gases is provided wherein the reducing gases are contacted with cerium oxide. The chlorided cerium oxide is regenerated in an oxidizing atmosphere to provide cerium oxide. This cerium oxide regenerated is again capable of reacting with chlorine in reducing gases.

Abstract: After aerating sewage sludge in a composting process, a stream of process air is treated to remove odors therefrom by injecting into the airstream an atomized mixture of dilute sulfuric acid and dilute surfactant to remove ammonia and odorous organic compounds therefrom. The airstream is then oxidized with bleach to remove sulfides and treated with a hydrogen peroxide solution to remove chlorine introduced by the bleach while maintaining the oxidation reaction. A dilution fan is used to further dilute the scrubbed airstream as the airstream is exhausted to the atmosphere.

Abstract: The invention is a multi-stage process for purifying hydrogen chloride containing acetylene and ethylene, from pyrolysis of 1,2-dichloroethane to provide highly pure hydrogen chloride for use in the preparation of silicon compounds. In the first stage, unsaturated by-products are chlorinated by reaction with an excess of chlorine gas. In the second stage, the unreacted chlorine gas remaining in the hydrogen chloride is reacted with an excess of defined olefins or chloroolefins and the hydrogen chloride is separated from the chlorination products and the excess olefins or chloroolefins by low-temperature rectification under pressure.

Abstract: Chlorine is removed from a gas stream by contacting the stream with a pulverized, oxidized bastnasite ore in the presence of water. The invention is particularly applicable to the processing of bastnasite ore for the recovery of rare earth compounds wherein there is produced a waste gas stream containing chlorine.

Abstract: Iodine and organic iodine compounds which may be radioactive and which may be found in waste gases or vapors from nuclear reactors can be removed from such gases or vapors by passing the iodine or organic iodine compound-containing gases or vapors through a layer of binder-free silver-exchanged molecular sieve granulates of the faujasite type.

Abstract: A method of treating a waste gas containing at least boron trichloride and chlorine comprises first treating the waste gas with a treating agent containing a magnesium compound by a dry process and then treating the waste gas with a treating agent containing a calcium compound by a dry process. Thus, it is possible to remove efficiently a chloride and chlorine containing gas from waste gas discharged from a dry etching process or other manufacturing process in the semiconductor industry. In addition, it is possible to reduce the amount of treating agent used, lengthen the treating agent replacing cycle, and facilitate the maintenance of the system.

Abstract: An adsorbent composition, method of preparing same, and method of treating a fluid stream with the absorbent are disclosed. Alumina and carbon are combined with water in preferred proportions in one embodiment. Sodium bicarbonate and impregnates such as Group 1A metal hydroxides and Group 7A salts of Group 1A metals can be added. Improved efficiency of removal of compounds such as hydrogen sulfide is achieved, and ignition temperature is reduced.

Abstract: A chlorine gas filtering material suitable for use in a high temperature oxygen environment, and a method of making the filtering material. The filtering material is prepared by impregnating a porous manganese dioxide and copper oxide hopcalite catalyst prepared by the carbonate method with sodium hydroxide. The process of making includes the steps of mixing the catalyst into a sodium hydroxide solution and then vacuum baking the impregnated catalyst for at least 8 hours, and preferably for 16 hours at a temperature of 240.degree. F.-260.degree. F.

Abstract: Transition metal carbides in which the carbon is in excess and is covalently bound to the metal are produced by pyrolyzing transition metal amides that have two or more metal atomos, such as hexakis(dimethylamido) ditungsten or dimolybdenum.

Abstract: Bromine is advantageously recovered from a free bromine-containing aqueous solution or gas by placing the solution or gas in contact with an adsorbent comprising a ZSM-5 zeolite having an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of at least 70 and heating the adsorbent at a temperature of at least 60.degree. C.

Abstract: Iodine and iodine compounds are removed by using an adsorbent comprising a silver loaded pentasil zeolite.

Abstract: A gaseous constituent such as SO.sub.2, HCl, or HF is removed from a gas stream in a granular bed filter containing granules coated with a sorbent material which is reactive with the gaseous constituent. Granules carrying reacted sorbent material are removed from the granular bed filter, cleaned of reacted sorbent material and coated with further sorbent material for reuse in the granular bed filter. Electrification of the filter bed permits simultaneous, highly efficient removal of particulates entrained in the gas stream.

Abstract: Disclosed are macroreticulate polymer scavengers functionalized with arsenic or phosphorus compounds. These scavengers are used for removing oxidants, protic acids and compounds that can be metallated, from arsine and phosphine.

Abstract: Waste gases and other noxious substances which are formed in connection with chemical processes and the manufacture of devices such as semiconductors and covalent hydrides and element organic compounds, etc. are treated so as to remove the noxious components.

Abstract: This disclosure concerns an improved phospho-gypsum recovery process in which phospho-gypsum waste product and coke are first heated to remove moisture, some SO.sub.2 and other vaporous matter, then heated to a higher temperature in a reducing atmosphere to remove and separately recover SO.sub.2, then further heated in an oxidizing atmosphere to about 1200.degree. to 1250.degree. C. to remove any unreacted carbon and calcium sulfide before entering an electric furnace. The disclosure also concerns passing the gas stream from the condenser-heat exchanger over the clinker from the electric furnace to scrub SO.sub.2 from said gas stream. The essence of the invention is the unique absorber system used to remove any and all remaining fluorine in the gases from the calciner/furnace. If not removed, the fluorine will severely harm the catalyst used in the contact sulfuric acid plant to which the gases are sent for recovery of sulfur values.

Abstract: A process involving mass transfer between two fluid cavities through the nnels of a microchannel plate (MCP). The mass transfer process may involve separation of organic chemicals like petrochemicals, vegetable oils, inorganic chemicals like steam stripping of bromine from aqueouspotassium chloride/potassium bromide, corrosive as well as sepration of hazardous gases.The MCP structures may have an electric field or electromagnetic field across the MCP to create synergestic mass transfer separation potential either to increase or decrease separations. Blood filtering as well as other biomedical separations are possible by this synergestic mass transfer.Catalytic depositions within the channels of the MCPs, either as wall coatings with the channels open or as solid porous catalytic material that has osmosis action thereacross further enhances chemical reactions during the separation process or during passage through the channels. This procedure can also be used for gas clean-up, such as combustor discharges.

Abstract: The invention relates to a process for the continuous wet or wet-catalytic purification of waste gases by adsorption and chemisorption of the gaseous pollutants on activated carbons with simultaneous desorption of these pollutants or their reaction products. The process is carried out at 100 to 800 times gravity acceleration in a centrifugal filter, in the rotor of which a bed of fine-grain or fibrous activated carbon is arranged. The waste gas passes through this bed in codirectional or counter-current flow to the wash liquid. The pollutants are washed out with the desorbent flowing from the center outwardly.

Abstract: Halogens and/or hydrogen halides in a gas can easily be removed from the gas by contacting the gas with an adsorbent comprising an activated carbon having as supported thereon (1) one or more components included in one of the three groups shown below and (2) one or more components included in the remaining two groups shown below:______________________________________ Group Component ______________________________________ I copper compound II zinc compound III (a) alkali metal compounds (b) alkaline earth metal compounds (c) compounds of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cd and Pb ______________________________________ .

Abstract: A process for removing halide ions from a hydrocarbon feedstream containing halogenated hydrocarbons wherein the contaminated feedstock is contacted with a solution of a suitable oxidizing acid containing a lanthanide oxide, the acid being present in a concentration of at least about 50 weight percent for a time sufficient to remove substantially all of the halide ion from the hydrocarbon feedstock.

Abstract: Decontaminating an aluminum melt by chlorination wherein the melt is blanketed with a layer of molten flux containing calcium oxide to consume any Cl.sub.2 and/or AlCl.sub.3 offgasses from the melt.

Abstract: A method of regenerating a nuclear-grade activated carbon filter, used to trap radioactive iodine, is accomplished by introducing suitable airborne chemical reducing agents into the air flow.

Abstract: In an exhaust gas scrubber having a plurality of absorption sections which are supplied with a chemical liquid for gas-liquid contacting, fresh liquid for makeup use is supplied to the section closest to the gas outlet and then is mixed gradually with the liquid being recycled to the section on the gas inlet side of the vessel, whereby the process permits exhaust gases with saturation humidity at temperatures of 75.degree. C. or upwards to be treated effectively with but a limited drainage of water.

Abstract: Hydrocarbon vapors containing HF, as from an HF alkylation refrigerated vent gas yield, the reactor settler, and the like are charged to a liquid knock-out drum to remove entrained liquid therefrom, the recovered liquid being pumped to storage in response to liquid level control on the knock-out drum. Recovered vapors are charged to a circulating aqueous caustic treater to yield HF-free vapors, as to a flare. The circulating caustic solution is indirectly heated in response to a preselected caustic solution temperature to prevent freezing. A high pressure rupture disc, upstream from the knock-out drum, affords a vapor relief safety by-pass of the treater. Dry gas, such as nitrogen or sweet, natural gas, continuously sweeps the relief line to maintain this line open and operable.

Abstract: Fuel gas produced in a coal distillation or gasification plant 1 is fed to a power plant 5 and chlorine, fluorine, sulphur and compounds thereof in the fuel gas are separated from the fuel gas, and also from flue or exhaust gas emanating from the power plant, in two stages. In a first stage, chlorine and fluorine and their compounds are separated, preferably in the dry using alkali metal or alkaline earth metal oxides, hydroxides or carbonates, in a separator 3. In a second stage sulphur and its compounds, together with further chlorine, fluorine and their compounds, if any, produced in the power plant, are removed from the flue or exhaust gas from the power plant in a desulphurizing plant 6. This two stage process is thermally more efficient and less costly than a process in which the chlorine, fluorine sulphur and their compounds are all removed at once from the fuel gas.

Abstract: The present invention provides an apparatus and process for separating and removing chemical impurities from air which impurities are difficult to absorb. The apparatus for carrying out the process of the present invention comprises a reaction tower (11, 51, 91) into which the air-gas mixture is fed, aperture means (35, 74, 96) in a wall (16, 60, 98) of the tower, at least one filter means (12, 52, 92) carried in the reaction tower, means for distributing (13, 58, 93) an absorbent medium onto the filter, collecting means (14, 54, 94) beneath the filter for collection of the absorbent medium passing through the filter, and fan means (15, 55, 95) provided in the aperture for creating a flow of air through the reaction tower for the separation of substantially all of the impurities therefrom.

Abstract: This invention relates to improvements in the execution of catalytic processes wherein chlorine in high state of purity is produced by reacting hydrogen chloride containing organic impurities with oxygen.

Abstract: A method and device of cooling and separating chlorides and fluorides from ammoniacal gas produced in the carbonization gasification of coal includes the addition of an aqueous salt solution having a concentration of at least one of chlorine and fluorine ions up to saturation to the ammoniacal gas in a color to form a salt solution enriched with chlorides, fluorides and ammonia compounds and a treated gas, and removing at least part of the enriched solution from the cooler.

Abstract: In the separation of traces of halogens and sulfur from a halogen- and/or sulfur-containing gas stream wherein the gas stream is contacted with a wash liquid to absorb the halogens and sulfur, the improvement which comprises including in the wash liquid heavy metal ions capable of forming difficultly soluble halides and sulfides. Preferably the heavy metal ions are silver or copper, and the insoluble heavy metal sulfide and/or halide is removed from the wash liquid which is recirculated. Almost quantitative removal is achieved in as little as 1 second of gas-wash liquid contact.

Abstract: This invention is a method for effecting preferential removal and immobilization of certain gaseous contaminants from gaseous UF.sub.6. The contaminants include fluorine and fluorides which are more reactive with CaCO.sub.3 than is UF.sub.6. The method comprises contacting the contaminant-carrying UF.sub.6 with particulate CaCO.sub.3 at a temperature effecting reaction of the contaminant and the CaCO.sub.3.

Abstract: The residual gas obtained in the pyrogenic production of metal oxides or metalloid oxides contain besides the desired product elemental chlorine if a chlorine containing starting material is employed. After cooling the residual gas the elemental chlorine is reacted to form hydrogen chloride by using an aqueous solution of a reducing agent and in this form the chlorine is subsequently washed out of the residual gas.

Abstract: The method of processing alkaline solutions containing radioactive iodine consists in dissolving irradiated fuels in a nitric acid solution. The vapors constituted essentially by nitrogen oxides, iodine and water formed during dissolution are passed into a condenser and then into a first absorption column in which the recombined nitric acid is formed. The recombined acid is returned to the dissolver while the gases discharged from the first absorption column are passed into a second absorption column in counterflow to an alkaline solution which is loaded with iodine and with nitrous ions. The alkaline solution discharged from the second absorption column is passed into a reaction vessel containing a mixture of nitric acid and sulphamic acid which destroys the nitrous products and releases the iodine.

Abstract: When halogen is bubbled into a body of water in the presence of catalysts of graphitized carbon, ruthenised titanium, platinised titanium or mixtures thereof, hydrohalic acid is formed at higher concentrations than obtained by water by itself.

Abstract: A method of scrubbing reaction products resulting from flame burning of fuels containing impurities such as sulfur compounds, chlorine compounds, and fluorine compounds. The scrubbing is accomplished by the addition to the fire chamber of additives which bind the impurities. The additives are supplied to the burner flame by way of a gaseous and/or liquid carrier medium flow, accompanied by the formation of a veil surrounding the burner flame.

Abstract: Impure gas streams are purified/treated in a gas-liquid phase contactor of cocurrent spray scrubber type, wherein the feed gas, together with a cocurrently descending spray of treatment liquid, are introduced into a contact zone under conditions such that the pressure of atomization of the liquid and the liquid dispersing velocity of the gas feed ensure effective interphase surface and contact time therefor, whereby the impure gas is efficiently physically scrubbed by said liquid, either with or without concomitant chemical reaction therebetween, and the dispersed liquid interphase is then vertically directed to a downstream separation zone wherein the gas stream is subjected to an abrupt change in direction and is thus separated from the interphase at essentially the original inlet velocity thereof and with essentially no content of treatment liquid, while at the same time essentially all of the atomized treatment liquid maintains its vertically downward descent to a liquid collection and recovery zone.

Abstract: HF is removed from hydrocarbon streams, e.g., a propane liquid stream from HF alkylation by water washing, the wash stream being contacted with solid caustic to remove moisture therefrom. The used wash water containing HF is combines with aqueous caustic obtained from said contacting and the admixture is used to contact HF acid soluble oil to remove HF therefrom. The thus, used aqueous stream separated from this last contacting is reacted with a calcium compound to form insoluble calcium fluoride and a supernatant aqueous liquid containing regenerated caustic. The regenerated caustic is used to remove the sulfur compounds from the alkylation hydrocarbons feed.

Abstract: Disclosed is a hypochlorite decomposition catalyst of nickel (II) oxide and NiCo.sub.2 O.sub.4 spinel, a hypochlorite destruction process using the catalyst, and a method of synthesizing the catalyst on a porous support.

Abstract: This invention is a process for the direct recovery of gaseous fluorine from waste-gas streams or the like. The process comprises passing the gas stream through a bed of anhydrous K.sub.3 NiF.sub.6 pellets to fluorinate the same to K.sub.3 NiF.sub.7 and subsequently desorbing the fluorine by heating the K.sub.3 NiF.sub.7 pellets to a temperature re-converting them to K.sub.3 NiF.sub.6. The efficiency of the fluorine-absorption step is maximized by operating in a selected and conveniently low temperature. The desorbed fluorine is highly pure and is at a pressure of several atmospheres. Preferably, the K.sub.3 NiF.sub.6 pellets are prepared by a method including the steps of forming agglomerates of hydrated K.sub.3 NiF.sub.5, sintering the agglomerates to form K.sub.3 NiF.sub.5 pellets of enhanced reactivity with respect to fluorine, and fluorinating the sintered pellets to K.sub.3 NiF.sub.6.

Abstract: An iodine adsorbent comprises an alumina carrier having a large number of pores having a mean pore size of 200 to 2,000 A and silver supported on the alumina carrier. The alumina carrier has a pore volume of at least about 0.1 cc/g.High percent iodine removal is obtained in a highly humid atmosphere, and an amount of silver supported on the carrier is much reduced.

Abstract: Hydrogen contamination of chlorine-containing gas, such as the chlorine gas from the electrolytic chlorine/caustic process and especially the tail gas from the chlorine liquefaction operation, is eliminated by reaction of the hydrogen directly in the gas mixture at elevated temperature in the presence of a catalyst, to effect combination of the hydrogen with chlorine to form hydrogen chloride, followed by scrubbing of the hydrogen chloride from the gas.

Abstract: A liquid solution containing a tri-halide from the halogen group consisting of bromine and iodine is passed in countercurrent flow with fluids containing sulfur compounds, including hydrogen sulfide, within a tower. The tri-halide solution removes selected sulfur compounds, including hydrogen sulfide, from the fluids and the halide solution is drained from the bottom of a tower for sulfur removal, electrolytic regeneration, and hydrogen release in order that a tri-halide from the electrolytic cell may be returned to the tower for continual removal of sulfur compounds, including hydrogen sulfide. A portion of the spent halide solution from the bottom of the tower is conducted to a point in the tower above the introduction of the tri-halide solution to prevent the loss of the diatomic halogen.

Abstract: A hydrocarbon hydroconversion catalyst is regenerated by (a) combustion, (b) chlorination or oxychlorination and (c) treatment with an oxygen-containing gas, and the gas discharged from the regeneration zone, before re-use, is (a) cooled down to below 70.degree. C., (b) subjected to double washing and (c) dried to reduce the water content of the gas to less than 2,500 ppm. An apparatus is also disclosed, certain parts of which are made of a material strongly resistant chlorine and other parts of a less resistant material with respect thereto.

Abstract: A process for removing I, R, Xe and Kr which involves the passage of the off gas stream through a tube-in-shell assembly, whereby the tubing is a PTFE membrane which permits the selective passages of the gases for removing and isolating the gases.