Abstract: A process for separating hydrogen chloride from a mixture including an N-(C1-C18)-alkyl-2-pyrrolidone and hydrogen chloride by distilling the mixture including an N-(C1-C18)-alkyl-2-pyrrolidone and hydrogen chloride at from 100 to 220° C. and from 50 to 850 hPa in the presence of water in a distillation column, condensing the water as water-hydrogen chloride azeotrope at the top by cooling, returning the water-hydrogen chloride azeotrope to the distillation column, separating off gaseous hydrogen chloride at the top and taking off the N-(C1-C18)-alkyl-2-pyrrolidone from the bottom.

Abstract: A treatment solution (2) containing fluoride is added to a cleaning solution (1) drained from a cleaning tank (11). Fluoride is allowed to react with fluorosilicic acid in the cleaning solution to settle a precipitate (4) containing fluorosilicate, and the precipitate (4) is removed. The cleaning solution regenerated in a regeneration apparatus (10) is again returned to the cleaning tank (11), and used as a cleaning solution for a CRT panel (20).

Abstract: A process for the conversion of boric acid to dry boron oxide by thermal decomposition is described. Boron oxide may be produced as a powder or in the form of pellets, and in either form may additionally be enclosed in a gas permeable container to control particulate contamination. Applications are further disclosed for the use of boron oxide formed by this process to remove water from evacuated chambers and from gases. Specific applications include removing water from both inert gases and reactive gases, especially halogen and halogenated gases. Further applications directed to optical amplifiers and gas purifiers are also discussed.

Abstract: A method for isolating 32 from a crude mixture containing HCl and an azeotropic mixture of 32 and HF is provided without the need to isolate any HF azeotrope.

Abstract: Hydrogen halides in the gas phase are separated by a process, comprising contacting a gas comprising at least two hydrogen halides with an adsorbent, whereby the adsorbent selectively adsorbs and retains at least one of the hydrogen halides.

Abstract: An effluent abatement system 200 that may be used to abate F2 gas content of effluent exhausted from a process chamber 35, such as effluent from a CVD chamber cleaning process includes a catalytic reactor 250 to reduce the content of F2 in the effluent 100. The system may further include a prescrubber 230 to add reactive gases to the effluent 100 and/or to treat the effluent 100 prior to treatment in the catalytic reactor 250. Alternatively reactive gases can be added to the effluent 100 by a gas source 220.

Abstract: A process for regenerating spent acid liquor feeds an acid liquor into a reactor having a first heating zone for evaporating a substantial portion of the liquid from the spent acid to produce acid vapors and metal salts without decomposing the acid. The metal salts are transferred to a second heating zone where the salts are roasted to form metal oxides. The acid vapors from the primary roasting furnace are then transferred to an absorption column to regenerate the acid. The first heating zone is operated at a temperature below the decomposition temperature of the acid and the metal salts. The second heating zone operates at a higher temperature to completely oxidize the metal salts.

Abstract: A method of treating a surface of a metal is provided. A source of fluoride ion is mixed with a source of acid to form hydrofluoric acid and, when applied to a metal surface to be treated, the hydrofluoric acid acts as a brightening agent.

Abstract: An organic solvent is separated from a waste stream comprising hydrofluoric acid, an organic solvent and etchant contaminants. The process comprises separating the hydrofluoric acid by subjecting the waste stream to at least one of the following processes: ion exchange; extraction of the hydrofluoric acid; electrophoresis; converting the hydrofluoric acid to an insoluble salt; to thereby obtain a first composition containing the hydrofluoric acid and a second stream containing the organic solvent and being substantially free of the hydrofluoric acid; and then distilling the second stream to recover the organic solvent free of the etching contaminants.

Abstract: In a method of regenerating a spent pickling solution composed of nitric acid and hydrofluoric acid and containing metal fluorides and metal nitrates, the pickling solution is heated in a reactor to about 300-1,000° C., the metal fluorides and the metal nitrates are pyrohydrolized, and the metal oxides formed as a result are removed as a granulate, and the gas produced in the fluodized bed reactor is dedusted, cooled and fed to an acid recovery unit. The spent pickling solution is initially separated in a separating process into a partial flow with free acid and into a partial flow enriched with metal salts, and the partial flow enriched with free acid is fed to the acid recovery unit and the partial flow enriched with metal salts is fed to the fluidized bed reactor.

Abstract: A process and an apparatus for treating an exhaust gas, in which a raw gas and high-boiling intermediate products contained in the exhaust gas let out from a CVD system employing a silicon-containing gas is brought into contact with a transition metal such as nickel or a silicide of such transition metals to decompose or convert them into stable halides, followed by detoxication treatment of the harmful components contained in the exhaust gas.

Abstract: A process for regenerating spent acid liquor feeds an acid liquor into a reactor having a first heating zone for evaporating a substantial portion of the liquid from the spent acid to produce acid vapors and metal salts without decomposing the acid. The metal salts are transferred to a second heating zone where the salts are roasted to form metal oxides. The acid vapors from the primary roasting furnace are then transferred to an absorption column to regenerate the acid. The first heating zone is operated at a temperature below the decomposition temperature of the acid and the metal salts. The second heating zone operates at a higher temperature to completely oxidize the metal salts.

Abstract: The invention relates to a process for the preparation of superazeotropic hydrochloric acid from metal chloride solutions, e.g. spent pickling solutions. The process is characterized in that the metal chloride solutions are thermally decomposed with the formation of a hydrochloric gas, that the hydrochloric gas is processed in a manner known per se into a superazeotropic mixture of hydrogen chloride and water, the superazeotropic gas mixture being condensed to yield a superazeotropic hydrochloric acid. The invention further relates to a process for ore and/or metal processing employing superazeotropic hydrochloric acid prepared according to the invention.

Abstract: Process and apparatus for regenerating spent acid liquor includes a primary roasting furnace for evaporating a substantial portion of the liquid from the spent acid to produce acid vapors and partially roasted metal salts. The partially roasted metal salts are transferred to a secondary roasting chamber where the acids adhering to the surface of the metal salts is vaporized and the metal salts are oxidized. The acid vapors from the primary roasting furnace are then transferred to an absorption column to regenerate the acid. The primary roasting furnace is operated at a different temperature from the secondary roasting chamber and has different retention times for the metal salts. The secondary roasting chamber includes a raking device to mix and convey the metal salts during the secondary roasting step to produce a uniformly roasted metal oxide.

Abstract: The invention relates to a method for recovering products from the defluorination of uranium hexafluoride. Recovered are a commercial grade anhydrous hydrogen fluoride and triuranium oxide through the use of two distinct reactors.

Abstract: Provided is a novel method and system for preparing ultra-high-purity buffered-hydrofluoric acid or ammonium fluoride controlled concentration The method comprises bubbling purified ammonia vapor into ultra-pure hydrofluoric acid. The inventive method and system can be used as an on-site subsystem in a semiconductor device fabrication facility for supplying the buffered-hydrofluoric acid and ammonium fluoride to points of use in the semiconductor device fabrication facility.

Abstract: The novel process for preparing pure hydrofluoric acid or pure hydrogen fluoride is characterized in that, after pretreatment by distillatioil/oxidation, a two-stage scrub is carried out using 65-90% strength by weight hydrofluoric acid and 90-100% strength by weight hydrofluoric acid and water is fed into the first or second scrubbing circuit and a corresponding amount of hydrofluoric acid is bled off to remove impurities.

Abstract: The present invention relates to a process for separating hydrogen chloride from a mixture comprising an N-(C1-C18)-alkyl-2-pyrrolidone and hydrogen chloride by distilling the mixture comprising an N-(C1-C18)-alkyl-2-pyrrolidone and hydrogen chloride at from 100 to 220° C. and from 50 to 850 hPa in the presence of water by means of a distillation column, condensing the water as water-hydrogen chloride azeotrope at the top by cooling, returning the water-hydrogen chloride azeotrope to the distillation column, separating off gaseous hydrogen chloride at the top and taking off the N-(C1-C18)-alkyl-2-pyrrolidone from the bottom.

Abstract: The invention relates to a novel process for removing arsenic compounds from the distillation bottoms from hydrogen fluoride distillation in which the distillation bottoms are first concentrated by evaporation of hydrogen fluoride until the temperature at the bottom is from 40 to 60° C., and the residue is then reacted with calcium hydroxide, calcium oxide, or a mixture thereof to give, in a simple manner, a product capable of disposal in a landfill.

Abstract: Provided is a novel method and system for preparing ultra-high-purity buffered-hydrofluoric acid or ammonium fluoride controlled concentration. The method comprises bubbling purified ammonia vapor into ultra-pure hydrofluoric acid. The inventive method and system can be used as an on-site subsystem in a semiconductor device fabrication facility for supplying the buffered-hydrofluoric acid and ammonium fluoride to points of use in the semiconductor device fabrication facility.

Abstract: To provide a process for recovering high quality hydrogen chloride rationally with good economical efficiency, particularly hydrogen chloride with an elevated quality level to be provided as the feedstock for the oxychlorination reaction in producing dichloroethane and a vinyl chloride monomer from a hydrogen chloride gas to be generated by the combustion of chlorine based waste. To use a process for recovering hydrogen chloride from chlorine based waste comprises adding water and a reducing agent to an acid gas obtained by the combustion of chlorine based waste to effect reaction to obtain a crude hydrogen chloride aqueous solution having an oxidation-reduction potential of not higher than 900 mV and then, distilling the crude hydrogen chloride aqueous solution to obtain a purified hydrogen chloride gas.

Abstract: A process for the conversion of boric acid to dry boron oxide by thermal decomposition is described. Boron oxide may be produced as a powder or in the form of pellets, and in either form may additionally be enclosed in a gas permeable container to control particulate contamination. Applications are further disclosed for the use of boron oxide formed by this process to remove water from evacuated chambers and from gases. Specific applications include removing water from both inert gases and reactive gases, especially halogen and halogenated gases. Further applications directed to optical amplifiers and gas purifiers are also discussed.

Abstract: A method of removing iron and halogen coloring materials from hydrochloric acid, by removing iron from the hydrochloric acid, and thereafter adding a nitrogen containing reducing agent to the hydrochloric acid.

Abstract: A process for separating and recovering hydrogen fluoride from a mixture with an organic compound especially a fluorine-containing compound by extraction with a solution of an alkali metal fluoride in hydrogen fluoride, phase separation and recovery. A process for producing a fluorine-containing organic compound by fluorinating a starting material with hydrogen fluoride and similarly recovering hydrogen fluoride from the product stream. The solution may be anhydrous or aqueous.

Abstract: An adsorbent and method for making it and its use in removing water from gaseous hydrogen halide. Magnesium halide supported on an activated carbon prepared under vacuum will remove water at 1 to 500 ppm.

Abstract: The disclosure relates to removing impurities from hexafluoroethane (CF3CF3), also known as Perfluorocarbon 116 (PFC-116) or Fluorocarbon 116 (FC-116), by using azeotropic distillation such that an overhead product consisting essentially of HCl-hexafluoroethane is formed, optionally combined with a phase separation step to break the HCl-hexafluoroethane azeotropic or azeotrope-like composition thereby permitting recovery of substantially pure hexafluoroethane. Unreacted hydrogen fluoride (HF) may be removed from hexafluoroethane during the above azeotropic distillation with HCl or alternatively by an azeotropic distillation wherein an HF-hexafluoroethane azeotropic or azeotrope-like composition exits overhead and substantially pure HF exits in the bottoms stream.

Abstract: Process and apparatus for regenerating spent acid liquor includes a primary roasting furnace for evaporating a substantial portion of the liquid from the spent acid to produce acid vapors and partially roasted metal salts. The partially roasted metal salts are transferred to a secondary roasting chamber where the acids adhering to the surface of the metal salts is vaporized and the metal salts are oxidized. The acid vapors from the primary roasting furnace are then transferred to an absorption column to regenerate the acid. The primary roasting furnace is operated at a different temperature from the secondary roasting chamber and has different retention times for the metal salts. The secondary roasting chamber includes a raking device to mix and convey the metal salts during the secondary roasting step to produce a uniformly roasted metal oxide.

Abstract: In order to reduce pollutants in the waste gas of regeneration plants for spent hydrochloric acid from pickling plants a process is provided, comprising the thermal decomposition of iron chloride in the spent pickling acid to iron oxide and gaseous hydrochloric acid, wherein to the spent pickling acid at least one compound is admixed which contains nitrogen having a low oxidation number, for example ammonium compounds, ammonia, urea or amides.

Abstract: A novel method is described whereby chlorine and sodium sulfate waste by-products from chemical by-products are recycled to form useful chemicals. Sodium sulfate is first reacted to form a metal sulfate and sodium chloride. The sodium chloride may be used as a chemical feed in chlor-alkali plants. The metal sulfate is then reacted to form an ammonium sulfate or bisulfate which in turn is reacted with chlorine to form sulfuric acid. The sulfuric acid may be used a chemical feed in chlorine dioxide plants and in various other chemical processes.

Abstract: In order to remove the methanesulphonyl chloride entrained by the gaseous HCl by-product, an amount of water ranging from 0.01 to 20%, relative to the mass of HCl to be treated, is injected into the HCl gas flow and the temperature is lowered to a value below or equal to 15° C.

Abstract: A process for producing a high-purity liquid chemical is provided. A chemical gas is successively purified over first and second purification columns by passing, countercurrently, a scrubbing solution of initially deionized high-purity water through the first and second purification columns, or by passing, countercurrently, a first scrubbing solution of initially deionized high-purity water through the first column and a second scrubbing solution of initially deionized water through the second column. Each of the scrubbing solutions gradually becomes a spent scrubbing solution loaded with impurity. A high-purity chemical gas leaves the second purification column with a low content of metallic elements. The high-purity chemical gas is subsequently dissolved in a liquid in a dissolution column including a top and a bottom. The liquid at the bottom of the dissolution column is collected and continuously recirculated, and is enriched with purified chemical gas, thereby forming a high-purity liquid chemical.

Abstract: Hydrogen fluoride production apparatus removes phosphate rock dust from a hot gas mixture exhausted from a phosphate rock defluorination kiln; cools the hot gas mixture in a heat exchanger to a low enough temperature that it can be brought into contact with acid-resistant polymeric materials without destroying them; uses a water spray scrubber for further cooling the gas and absorbing the fluoride values as HF-rich liquor; and pumps the HF liquor to a holding tank. One such plant uses a gas tube steam boiler as the heat exchange and has several series-connected scrubbers to extract the fluorine values from the kiln exhaust so that the residual gas mixture can be exhausted into the atmosphere without exceeding permissible fluorine value levels. In this arrangement water is fed into the scrubber furthest from the boiler to extract HF from the process gas, and an HF-laden process liquor is fed out of the furthest scrubber into the second furthest scrubber, where it is sprayed into the gas stream.

Abstract: The present invention provides compositions that are intimate mixtures of hydrogen fluoride and a polymer. The compositions of the invention are less hazardous and, therefore, more conveniently stored, transported, and handled in comparison to pure hydrogen fluoride. Further, the hydrogen fluoride may be readily recovered from the compositions of the invention for use.

Abstract: Water present in a hot gaseous product stream from a reactor system A.B (FIG. 1) containing hydrogen fluoride is separated from the stream in order to eliminate a potentially corrosive combination of water and HF. The water is removed by contacting the gaseous product stream with liquid HF in a distillation column so as to obtain a bottoms product containing liquid HF and water and a top product containing dry HF and the product to be recovered. The invention encompasses the separation process, a vessel for carrying out the process (FIGS. 2 to 4), a control system for the liquid HF supply to the distillation column (FIGS. 5 and 6) and a recovery system for recovering HF employed during operation of the reactor system in different regimes employing HF as a fluorination agent, as a diluent during catalyst regeneration and/or catalyst prefluorination (FIG. 7).

Abstract: A system for purification and generation of hydrofluoric acid on-site at a semiconductor device fabrication facility. An evaporation stage (optionally with arsenic oxidation) is followed by a fractionating column to remove most other impurities, an Ionic Purifier column to suppress contaminants not removed by the fractionating column, and finally the HF Supplier (HFS).

Abstract: A method for purifying liquefied corrosive gases of metallic impurities is described. The principle for this purification method relies on vapor-phase transfilling the vapor phase from a source container into a receiving container. This method has been observed to decrease metal concentrations by a factor of at least 1000 and decreases the metallic impurity levels in the resulting condensate. The vapor transfer is accomplished by controlled differential pressure rather than mechanical pumping, thereby generating no particle or metal impurities.

Abstract: Process for extraction or recovery of acids, in particular hydrofluoric acid, hydrochloric acid and nitric acid, from solutions of these acids containing metal, by pyrohydrolytic treatment and subsequent absorption and/or condensation of the acid gases thus formed in an aqueous absorption solution, in which process the solids produced are removed. In order to guarantee economical acid recovery in existing plants without requiring large-scale adaptation, the waste pickling liquor is subjected to pre-concentration first of all before pyrohydrolysis, using the heat contained in the exhaust gas from the pyrohydrolysis.

Abstract: The present invention provides a process for recovering a volatile acid charaterized by bringing a waste liquid containing the volatile acid into contact with an amine having a boiling point of at least 50.degree. C. to thereby cause the amine to tonically adsorb the acid from the waste liquid, and thereafter heating the amine to desorb the acid, and a process for treating waste water utilizing this process.

Abstract: Process for removing organic constituents from a high pressure exhaust gas stream in a bromine assisted air oxidation process in which the exhaust gas contains methyl bromide.

Abstract: An adsorbent and method for removing water from gaseous HCl. MgCl.sub.2 supported on an activated carbon or silica gel substrate activated by heating to a temperature between 150.degree. C. (302.degree. F.) and 300.degree. C. (572.degree. F.) under vacuum will remove water at partial pressures of below 0.5 torr. Activation of the MgCl.sub.2 supported adsorbent can also be effected by heating the adsorbent between 270.degree. C. (518.degree. F.) and 400.degree. C. (752.degree. F.) under nitrogen.

Abstract: A process is disclosed for removing the very fine oxide particles produced during regeneration of used pickling acids by pyrolysis. The process includes the step of spraying water into the gaseous stream to produce a mist of fine droplets and thereafter passing the gaseous stream through a liquid separator. The invention is also directed to a plant for carrying out the process where the plant includes a nozzle to spray water droplets into the gaseous stream before the drop separator.

Abstract: A process and an apparatus for the production of iron oxides having low chloride ion content comprising charging of a free HCl containing iron chloride solution into a spray roaster with a feeding device and a spray boom for charging the iron chloride containing solution into a reaction chamber heated by combustion gases thermally decomposing the solution into iron oxide, HCl gas and reaction gases a discharging device for the iron oxide and a cooling zone between the burner's focal plane and the discharging device cooling of iron oxide granules to temperatures at less than 450.degree. C. reducing the concentration of HCl gas to less than 10 volume percent charging the layer of iron oxide granules onto a conveyor plate charged with hot steam and feeding the exhaust gases into the central combustion duct of the spray roaster. The resulting iron oxide has a residual chloride ion content of less than 500 ppm Cl.sup.- and a specific surface area in excess of 3.5 m.sup.3 /g.

Abstract: A process and apparatus for the removal of water from corrosive halogen gases, particularly chlorine- or bromine-containing gases, down to .ltoreq.100 ppb water concentration are described. The critical component is a high silica zeolite, preferably high silica mordenite, which in a variety of physical forms is capable of dehydrating such gases to .ltoreq.100 ppb or .ltoreq.50 ppb without being detrimentally affected by the corrosive nature of the gases in the presence of water. The high silica zeolite is produced by the removal of alumina from a natural or synthetic zeolite while retaining the desirable zeolite structure, to a silica:alumina ratio of from 20-2000:1. Metal cations which may be depleted by the alumina removal may be replaced by solution impregnation. Halogen- or halide-containing gases, or those with equivalent corrosion properties, may be dehydrated without deterioration of the high silica zeolite.

Abstract: The instant invention provides a process for reducing chloride content from by-products generated during production of methylchlorosilanes, comprising, (a) hydrolyzing the by-products by combining the by-products with an aqueous medium, the aqueous medium optionally comprising a surfactant, at a pH of at least about 7 and at a temperature above about 0.degree. C. to yield a first phase comprising essentially solids and a second phase comprising an aqueous phase; (b) separating the first and second phase; and (c) oxidizing the solids from the first phase at a temperature of at least about 300.degree. C. for up to about 24 hours to yield a residue comprising less than about 1% by weight of chloride. The solids from the first phase may alternatively be reduced under a hydrogen flow, at a temperature of at least about 500.degree. C. for up to about 24 hours.

Abstract: There is provided a process to recover phthalic anhydride from a plastic material which contains a phthalate ester as a plasticizer comprising the steps of:(a) heating the plastic material so that the plastic material is gasified to produce a first product,(b) contacting the first product with alumina catalyst so that the product is catalytically cracked to produce a first catalytically cracked product comprising phthalic anhydride; and(c) recovering phthalic anhydride from the first catalytically cracked product.

Abstract: A method for the removal and purification of substantially all of the fluoride ions contained in a solution containing greater than 10 parts per million (ppm) fluoride ion, a mixture of other anions, silicon in the form of a fluorosilicic acid, silicic acid, silicates, or silicon tetrafluoride, and optionally also containing complex metal fluorides, to produce an ultrapure hydrofluoric acid, comprising the steps of (a) adjusting the pH of the solution to an alkaline pH to hydrolyze the fluorosilicic acid and any complex metal fluorides; (b) removing the fluoride ions and other anions from the solution by passing the solution through an ion exchange resin, where the ion exchange resin is adapted to adsorb substantially all of the fluoride passed over the ion exchange resin; (c) displacing the fluoride ions and other anions bound to the ion exchange resin, thereby forming a mixture of anions in an effluent emanating from resin; (d) optionally concentrating the effluent at a high pH and then lowering the pH; and

Abstract: Highly purified ammonia for use in semiconductor manufacturing is prepared on-site by drawing ammonia vapor from a liquid ammonia reservoir, passing the vapor through a filter capable of filtering out particles of less than 0.005 micron in size, and scrubbing the filtered vapor in a high-pH aqueous scrubber.

Abstract: A process for forming an aqueous chloride leachant from a spent aqueous chloride leach liquor which process comprises passing a spent aqueous chloride leach liquor and gases containing hydrogen chloride through a preconcentrator to form a concentrated aqueous chloride leach liquor by partial evaporation of water therefrom and absorption of hydrogen chloride; withdrawing a portion of the concentrated aqueous chloride leach liquor; roasting the remainder of the concentrated aqueous chloride leach liquor to generate a metal oxide, and gases containing hydrogen chloride; and passing the gases containing hydrogen chloride to the preconcentrator.

Abstract: There is provided an azeotropic mixture of hydrogen fluoride (HF) and 1,1-difluoroethane (HFC152a). In addition, there is provided a process for the production of HFC152a having a step of more effectively recovering HF which does not contain HFC152a or HFC152a which does not contain HF in which step an azeotropic mixture is distilled off from a column top by subjecting a mixture containing HFC152a and HF, so that HF which does not contain HFC152a or HFC152a which does not contain HF is recovered from a column bottom.

Abstract: A process for the treatment of a hydrated mixture of a salt which comprises an inorganic fluoride and hydrogen fluoride to remove water from the mixture wherein the salt mixture contains an excess of hydrogen fluoride, which process comprises forming a liquid phase of the said mixture by melting the salt therein and feeding an inert gas through the liquid phase of the mixture.