Class 423/471 - Recovery or purification

Subclass of Class 423 - Chemistry of inorganic compounds
Definition: Products or processes in which the ammonium halide is obtained
No. of patents: 26
Last issue date: 04/25/2006

Number	Title	Issue Date
7033562	Ammonia recovery in the preparation of silazanes and polysilazanes Silazanes and/or polysilazanes are prepared by ammonolysis reaction in liquid anhydrous ammonia by introducing at least one halosilane into the ammonia. In addition to the silazane and/or polysilazane, an ammonolysis by-product also results. A substantially more eff...	04/25/2006
6350425	On-site generation of ultra-high-purity buffered-HF and ammonium fluoride 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...	02/26/2002
6180012	Sea water desalination using CO2 gas from combustion exhaust The invention relates to desalination of Sea water and of brakish water, and removal of harmful CO2 gas in exhaust from combustion apparatuses. The exhaust, rich in carbon dioxide (CO2) is diverted to a process chamber, where Sea wat...	01/30/2001
5958353	Method for reducing atmospheric pollution The invention provides a method for reducing atmospheric pollution caused by a pollutant selected from the group consisting of CO2, SO2 and a mixture thereof, the pollutant being contained in industrial gases being emitted to the atm...	09/28/1999
5679315	Method of production of high purity silica The present invention provides a basic method for producing high purity silica and ammonium fluoride from silicon tetrafluoride-containing gas, particularly the gas generated by acidulation. The basic method comprises recovering silicon tetrafluoride-cont...	10/21/1997
5458864	Process for producing high-purity silica by reacting crude silica with ammonium fluoride A process for producing a high-purity silica, which comprises the steps of reacting a crude silica with ammonium fluoride, acid ammonium fluoride or a mixture thereof in an aqueous medium to produce ammonium silicofluoride, separating the ammonium silicof...	10/17/1995
5290531	Method of making ammonium bromide and calcium bromide A method of converting sodium bromide brine to ammonium bromide brine and optionally to calcium bromide is disclosed. The method involves introducing ammonia and carbon dioxide into the reactant brine, removing a resulting bicarbonate precipitate, driving...	03/01/1994
5266289	Process for producing high-purity silica by reacting crude silica with ammonium fluoride A process for producing a high-purity silica, which comprises the steps of reacting a crude silica with ammonium fluoride, acid ammonium fluoride or a mixture thereof in an aqueous medium to produce ammonium silicofluoride, separating the ammonium silicof...	11/30/1993
5165907	Method of production of high purity silica and ammonium fluoride A method for producing high purity silica and ammonium fluoride from silicon tetrafluoride-containing gas wherein silicon tetrafluoride-containing gas from the acidulation of phosphorus-containing rock is recovered and the liquid entrainment is separated ...	11/24/1992
5073337	Rare earth/iron fluoride and methods for making and using same A particulate mixture of Fe2 O3 and RE2 O3, where RE is a rare earth element, is reacted with an excess of HF acid to form an insoluble fluoride compound (salt) comprising REF3 and FeF3 pre...	12/17/1991
5028407	Method of production of high purity fusible silica A method of producing a high purity silica powder which can be fused to form transparent, bubble-free particles. An ammonium fluosilicate solution is purified preliminarily by removing colloidal-sized silica onto which impurities in the solution have been...	07/02/1991
4981664	Method of production of high purity silica and ammonium fluoride A method for producing high purity silica and ammonium fluoride from silicon tetrafluoride-containing gas wherein silicon tetrafluoride-containing gas from the acidulation of phosphorus-containing rock is recovered and the liquid entrainment is separated ...	01/01/1991
4935219	Process for obtaining ferric oxide and ammonium salts The process of the invention is carried out in gaseous phase by the action of ammonia on the aqueous solutions of iron salts in an appropriate reacting vessels....	06/19/1990
4919906	Processes and equipment for production of elemental phosphorus and thermal phosphoric acid New processes and equipment are disclosed for producing elemental phosphorus and thermal phosphoric acid. Benefits are listed below. 1. Phosphorus-containing solids are recycled to smelting furnaces thus eliminating hazardous waste generation. 2. Phosphorus fu...	04/24/1990
4915705	Production of silica and fluorine-containing coproducts from fluosilicic acid A process for producing high grade silica and fluorine-containing coproducts from fluosilicic acid is described. To produce silica, the fluosilicic acid is reacted with aqueous ammonia to produce a solid silica product and a solution of ammonium fluoride....	04/10/1990
4882134	Recovery of hydrogen fluoride from an aqueous solution containing ammonium fluoride and hydrogen fluoride A method of recovering HF from an aqueous solution containing NH4 F and HF is provided. The solution is contacted with a water-immiscible, amine-containing extractant which extracts HF in preference to NH4 F. The HF:NH4 F ...	11/21/1989
4859443	Preparation of silicon nitride powder Silicon nitride powder is prepared in a gas-phase reaction by reacting silicon tetrachloride with ammonia at above 500° C. in a fluidized bed of silicon nitride particles. An amorphous silicon nitride having a BET specific surface area of greater than 50...	08/22/1989
4741893	Process for producing fluorides of metals Process for producing fluorides of Mo, W, Nb, Ta, V, Re, Ti, Zr, Hf, Co, Ni, Cr, Sb, Sn, Zn, Pb, Al and rare earth metals comprising heating fluorine-containing ammonium salts of corresponding metals in a stream of an inert or reducing gas to convert them...	05/03/1988
4670230	Process for selectively stripping iron ions from an organic solvent A process for selectively stripping and separating iron ions from an organic solvent (A) which comprises bringing the organic solvent (A) containing iron and zinc ions, and containing one or more compounds selected from the group consisting of alkyl phosp...	06/02/1987
4315903	Reducing the consumption of anthraquinone disulfonate in stretford solutions A process for treating a hydrogen sulfide-containing hydrogenated Claus process tail gas to convert the hydrogen sulfide to elemental sulfur in which said gas is contacted with an aqueous alkaline solution containing a water-soluble metal vanadate, a wate...	02/16/1982
4234429	System for separating particulate matter into soluble and insoluble portions Particulate matter collected by an environmental air quality control device may be in part toxic in nature and thus not readily disposable. By separating the toxic portion of the particulate matter from a nontoxic portion, disposal of nontoxic portion may...	11/18/1980
4200622	Purification of ammonium fluoride solutions In the purification of an ammonium fluoride solution containing silicic acid by adding iron (III) ions and precipitating the iron (III) ions at a pH above 8.5 and a concentration of free ammonia in the solution of more than about 1% by weight, the silicic...	04/29/1980
4122220	Method for reducing the gas permeability of a sintered porous silicon nitride body Silicon nitride bodies are improved by being impregnated with a silicon halide which is then converted to silicon imide in the pores of the body, which, in turn, is converted into silicon nitride....	10/24/1978
4060594	Reducing the consumption of anthraquinone disulfonate in stretford solutions A process for treating a hydrogen sulfide-containing hydrogenated Claus process tail gas to convert the hydrogen sulfide to elemental sulfur in which said gas is contacted with an aqueous alkaline solution containing a water-soluble metal vanadate, a wate...	11/29/1977
4000251	Method of purifying ammonium fluoride solutions Newly precipitated MnO(OH)2 is either added to an NH4 F solution that has been made slightly basic or this compound is formed in the NH4 F solution by adding an Mn (II) and an Mn (VII) salt solution. MnO(OH)2 ab...	12/28/1976
3989805	Process for the production of aluminum chlorohydroxides having a controlled chlorine content A process is described whereby aluminum chlorohydroxide having a controlled chlorine content is prepared by subjecting a mineral containing aluminum oxide or hydroxide (e.g. bayerite, gibbsite, diaspore, boehmite or alumina bayer) is subjected to a prelim...	11/02/1976

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Class 423/471 - Recovery or purification