Acid Leaching Patents (Class 423/20)
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Patent number: 5826162Abstract: A process for facilitating removal of one or more impurities from titaniferous material containing the impurities in a form which is highly soluble in acid. The material is in turn leached with a sulphuric acid solution and with a hydrochloric acid solution in either order. To enhance the susceptibility of the impurities to removal, the hydrochloric acid leach is augmented by one or more of the following: (i) addition of an effective amount of an added chloride salt; (ii) pre-treatment of the titaniferous material with a solution of an effective amount of a carbonate salt, preferably an alkali metal or alkaline earth metal carbonate; and/or (iii) pre-treatment of the titaniferous material with a solution of an effective amount of a hydroxide, preferably an alkali metal or alkaline earth metal hydroxide.Type: GrantFiled: October 28, 1996Date of Patent: October 20, 1998Assignee: RGC Mineral Sands LimitedInventors: Halil Aral, Warren John Bruckard, David Edward Freeman, Ian Edward Grey, Martin Richard Houchin, Kenneth John McDonald, Graham Jeffrey Sparrow, Kaye Patricia Hart, Harold Robert Harris
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Patent number: 5745835Abstract: A process and apparatus for dissolving a mixed oxide or mixture of oxides of uranium and plutonium. The powder is added with nitric acid to a chamber to dissolve uranium oxide, and the solution is circulated through a circuit of the apparatus with a portion of the solution passing through a filter. At least a portion of the filtered solution containing dissolved uranium oxide is removed from the apparatus, while returning non-filtered circulating solution containing non-dissolved plutonium oxide to the chamber. The removal of solution is then terminated, a monovalent silver salt is added and divalent silver is generated in-situ by electrolysis, the divalent silver causing dissolution of the plutonium oxide.Type: GrantFiled: September 6, 1996Date of Patent: April 28, 1998Assignee: Compagnie Generale Des Matieres NucleairesInventors: Marie-Helene Mouliney, Claude Bernard
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Patent number: 5686052Abstract: The invention relates to a process for the processing of nuclear targets and/or fuels based on metallic aluminium by dissolving with the aid of aqueous tetramethylammonium hydroxide (TMAOH) solutions.Dissolving can consist of a total dissolving in a single stage of the core and the can of the nuclear fuel by TMAOH or a decanning of the can by TMAOH, followed by a nitric dissolving of the core. The use of TMAOH eliminates the disadvantages associated with dissolving in a concentrated nitric or sodium medium and decanning with soda and in particular permits the easy vitrification of the effluents produced by the process.Type: GrantFiled: September 17, 1996Date of Patent: November 11, 1997Assignee: Commissariat a l'Energie AtomiqueInventors: Jean-Philippe Dancausse, Georges Armengol, Serge Caron
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Patent number: 5678167Abstract: The powdered form of nuclear fuels such as uranium dioxide and plutonium dioxide are dispersed in an about 3N aqueous nitric acid solution, and irradiated by UV rays at a wavelength of approximately 300 nm in order to improve a dissolving rate of the nuclear fuels. This enables easy and efficient dissolution of the nuclear fuels.Type: GrantFiled: November 13, 1995Date of Patent: October 14, 1997Assignee: Doryokuro Kakunenryo Kaihatsu JigyodanInventors: Yukio Wada, Kyoichi Morimoto, Takayuki Goibuchi, Hiroshi Tomiyasu
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Patent number: 5640703Abstract: A process for the treatment of solid waste material which is or is suspected to be contaminated with plutonium or compounds thereof with or without other hazardous contaminants, which process includes: contacting the said material with and thereby dissolving contaminants as complexes by a liquid medium which comprises Solution X which comprises an aqueous solution which is free of ingredients which are naturally degradable to non-toxic products with or without mild physical assistance such as heat or ultra-violet radiation, said solution comprising:(a) carbonated water;(b) a conditioning agent; and(c) a complexing agent which comprises the anion of a single or multiple carboxylic acid species having from 2 to 6 carbon atoms in each carboxylic acid species;and separating the liquid medium from the waste material and recovering the dissolved contaminants from the liquid medium and wherein the step of contacting the waste material with the said liquid medium is preceded by a step of contacting the waste materialType: GrantFiled: January 29, 1996Date of Patent: June 17, 1997Assignee: British Nuclear Fuels plcInventors: Kenneth Walter Brierley, Michael Robert Ellison
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Patent number: 5640701Abstract: Soil comprising small soil particles, clay and silt particles, humus, fine vegetation, and contaminated with soluble or insoluble radioactive species is treated by first introducing an aqueous extracting solution comprising a mixture of sodium and potassium carbonate (or bicarbonate), or ammonium carbonate (or bicarbonate) into the soil to solubilize and disperse the radioactive species into solution. The extracting solution has a pH greater than or equal to about 7.5. Contaminated fine vegetation then is separated from the soil and extracting solution. Next, an acid like hydrochloric acid is introduced into the soil. The acid is added in an amount sufficient to lower the pH of the extracting solution at which point desirable organic material will substantially precipitate or coagulate from the extracting solution. The cleansed soil particles, including organic matter, is separated from the contaminated extracting solution.Type: GrantFiled: December 29, 1992Date of Patent: June 17, 1997Assignee: Westinghouse Electric CorporationInventors: David C. Grant, Edward J. Lahoda, Albert J. Dietrich
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Patent number: 5587142Abstract: A method of dissolving metal oxides using a mixture of a di- or polyphosphonic acid and a reductant wherein each is present in a sufficient amount to provide a synergistic effect with respect to the dissolution of metal oxides and optionally containing corrosion inhibitors and pH adjusting agents.Type: GrantFiled: June 6, 1995Date of Patent: December 24, 1996Assignee: Arch Development CorporationInventors: Earl P. Horwitz, Renato Chiarizia
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Patent number: 5578109Abstract: A process for facilitating the removal of impurities e.g. radionuclides, such as uranium and thorium, and/or one or more of their radionuclide daughters, from titaniferous material includes contacting the titaniferous material with one or more reagents at an elevated temperature selected to enhance the accessibility of at least one of the radionuclide daughters in the titaniferous material. The reagent(s) may be a glass forming reagent and is selected to form a phase at the elevated temperature which disperses onto the surfaces of the titaniferous material and incorporates the radionuclides and one or more radionuclide daughters. The titaniferous material may be, e.g., ilmenite, reduced ilmenite, altered ilmenite or synthetic rutile.Type: GrantFiled: April 6, 1995Date of Patent: November 26, 1996Assignee: RGC Mineral Sands, Ltd.Inventors: Harold R. Harris, Halil Aral, Warren J. Bruckard, David E. Freeman, Martin R. Houchin, Kenneth J. McDonald, Graham J. Sparrow, Ian E. Grey
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Patent number: 5573738Abstract: Soil, contaminated with radioactive material such as uranium, is treated to remove the radioactive contaminant. The soil is first pre-processed to remove and clean oversized particles for release back to the environment as recovered soil. Pre-processing also includes removal of metallic uranium from the soil by gravimetric separation for off-site disposal. An aqueous slurry is formed from the pre-processed feed which is fed to a mechanical separation device. Particles greater than 10 mesh are crushed to provide a uniform feed slurry. The slurry is processed in an aqueous leaching solution of sulfuric acid, hydrogen peroxide and iron to remove uranium. Particulate matter is removed from the acidic slurry; the remaining fine particulate matter is then submitted to a second-stage leaching to remove residual uranium. Uranium is recovered from the combined leaching solutions by either a two-stage precipitation process or by passage over an ion-exchange material.Type: GrantFiled: July 8, 1994Date of Patent: November 12, 1996Assignee: Lockheed Martin CorporationInventors: Jonathan K. Ma, Andrea W. Chow, Scott A. Ranger, David W. Peters, Ronald F. May
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Patent number: 5523514Abstract: The invention relates to the dissolving of plutonium and/or other radioactive elements in an aqueous solution by microwave heating.According to the invention, solid or liquid products containing plutonium and/or other radioactive elements are introduced into a container (7) containing an acid solution, comprising hydrofluoric acid and nitric solution, followed by the microwave heating of the solution containing these products using a chamber or tank (5) placed in a tight enclosure (1), which is supplied with microwaves by means of a coaxial cable or a waveguide (11) connected to the generator (9) located outside the enclosure.The solid products can be plutonium dioxide PuO.sub.2 or organic or mineral radioactive waste materials such as gloves, cellulose products, ion exchange resins, etc. The liquid products can be contaminated organic solvents such as tributyl phosphate in dodecane.Type: GrantFiled: April 13, 1993Date of Patent: June 4, 1996Assignee: Compagnie Generale des Matieres Nucleaires - CogemaInventors: Gerard Cauquil, Michel Sourrouille
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Patent number: 5516496Abstract: The process for converting feed materials of high mineral content and substantial radioactivity levels to concentrated radionuclide products of high radioactivity levels and to other products of discard or very low radioactivity levels, wherein the feed materials consists of a difficultly soluble matrix contain substantial metal, fluorine, and radionuclide values assaying above about 30 pCi/g, the process having the steps of contacting the feed materials with high temperature steam of from about 200.degree. C. to about 1500.degree. C.Type: GrantFiled: June 1, 1995Date of Patent: May 14, 1996Assignee: Advanced Recovery Systems, Inc.Inventor: Randall P. Slage
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Patent number: 5494648Abstract: A process for removal of thorium from titanium chlorinator waste comprising: (a) leaching an anhydrous titanium chlorinator waste in water or dilute hydrochloric acid solution and filtering to separate insoluble minerals and coke fractions from soluble metal chlorides; (b) beneficiating the insoluble fractions from step (a) on shaking tables to recover recyclable or otherwise useful TiO.sub.2 minerals and coke; and (c) treating filtrate from step (a) with reagents to precipitate and remove thorium by filtration along with acid metals of Ti, Zr, Nb, and Ta by the addition of the filtrate (a), a base and a precipitant to a boiling slurry of reaction products (d); treating filtrate from step (c) with reagents to precipitate and recover an iron vanadate product by the addition of the filtrate (c), a base and an oxidizing agent to a boiling slurry of reaction products; and (e) treating filtrate from step (d) to remove any remaining cations except Na by addition of Na.sub.2 CO.sub.3 and boiling.Type: GrantFiled: January 31, 1994Date of Patent: February 27, 1996Assignee: The United States of America as represented by the Secretary of the InteriorInventors: Richard S. Olsen, John T. Banks
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Patent number: 5489736Abstract: A process for the treatment of material which is or is suspected to be contaminated with one or more actinides or compounds thereof, which process includes contacting the said material with a liquid medium which comprises an aqueous solution which is free of heavy metal ions (prior to use thereof) and comprises ingredients which are naturally degradable to non-toxic products with or without mild physical assistance such as heat or ultra-violet radiation, said solution comprising:(a) carbonated water;(b) a conditioning agent; and(c) a complexing agent which comprises the anion of a carboxylic acid having from 2 to 6 carbon atoms;wherein the said process is for treatment of solid organic wastes which are or are suspected to be contaminated with plutonium or compounds thereof with or without other hazardous contaminants and includes the steps of shredding the organic waste material, intimately mixing the shredded waste material with the said liquid medium thereby dissolving contaminants as complexes in said liquType: GrantFiled: July 21, 1994Date of Patent: February 6, 1996Assignee: British Nuclear Fuels PLCInventors: Kenneth W. Brierley, Michael R. Ellison
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Patent number: 5482688Abstract: A two-step process for dissolving plutonium metal, which two steps can be carried out sequentially or simultaneously. Plutonium metal is exposed to a first mixture containing approximately 1.0M-1.67M sulfamic acid and 0.0025M-0.1M fluoride, the mixture having been heated to a temperature between 45.degree. C. and 70.degree. C. The mixture will dissolve a first portion of the plutonium metal but leave a portion of the plutonium in an oxide residue. Then, a mineral acid and additional fluoride are added to dissolve the residue. Alteratively, nitric acid in a concentration between approximately 0.05M and 0.067M is added to the first mixture to dissolve the residue as it is produced. Hydrogen released during the dissolution process is diluted with nitrogen.Type: GrantFiled: February 7, 1994Date of Patent: January 9, 1996Assignee: The United States of America as represented by the United States Department of EnergyInventors: Michael A. Vest, Samuel D. Fink, David G. Karraker, Edwin N. Moore, H. Perry Holcomb
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Patent number: 5478538Abstract: The specification discloses a process for removing radionuclides from zircon. The process involves thermally decomposing the zircon in the presence of suitable additives, extracting the radionuclides chemically and recovering zirconia and silica. Suitable additives include fluxes, silica and any oxide capable of forming a silicate with silica when heated. Chemical treatments disclosed include leaching with mineral acids and strong organic acids. Methods of stabilizing the radionuclides extracted by leaching are also disclosed. One method involves spray roasting. Another method involves neutralization of leach liquor and recovery of radionuclide solids by filtration or other suitable liquid/solid separation techniques.Type: GrantFiled: December 14, 1993Date of Patent: December 26, 1995Assignee: Wimmera Industrial Minerals Pty LtdInventors: Michael J. Hollitt, Ross A. McClelland, Matthew J. Liddy, Ian E. Grey, Christopher A. Fleming
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Patent number: 5434331Abstract: A process for the decontamination of solid surfaces contaminated with radioactive or heavy metal species using a solution based on one or more non-persistent complexing agents, or for the chemical cleaning of steam generator sludge using such a solution, or for removing radioactive or heavy metal species from a solution using a combination of a one or more non-persistent complexing agents and a solid support, followed in each case by thermal or thermal-chemical treatment to decompose said non-persistent complexing agent. The preferred non-persistent complexing agents are hydroxamic acids, and the most preferred is acetohydroxamic acid.Type: GrantFiled: November 17, 1992Date of Patent: July 18, 1995Assignee: The Catholic University of AmericaInventors: Aaron Barkatt, Stephanie A. Olszowka
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Patent number: 5425927Abstract: Hafnium dioxide contaminated with 0.1 to 1 weight percent uranium dioxide is contacted with an aqueous acid such as nitric acid, hydrochloric acid, sulfuric acid and mixtures thereof to leach the uranium dioxide from the hafnium dioxide, thereby producing a slurry of a uranium-containing leachate containing hafnium dioxide solids. The slurry is filtered to separate the uranium-containing leachate from the hafnium dioxide solids, which are then dried to produce hafnium dioxide containing less than about 0.005 wt % uranium dioxide. The hafnium dioxide may then be released for uncontrolled commercial uses.The separated uranium-containing leachate is neutralized to precipitate uranyl hydroxide, which is then separated from the leachate. The uranyl hydroxide may be processed to produce uranium-containing products or may be disposed of as radioactive wastes having a fraction of the total volume of radioactive wastes which would need to be buried if the hafnium dioxide could not be recovered for commercial uses.Type: GrantFiled: June 27, 1994Date of Patent: June 20, 1995Assignee: Westinghouse Electric CorporationInventor: Roy G. Walker
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Patent number: 5422084Abstract: The invention relates to a process for dissolving plutonium dioxide by means of OH.sup.- radicals produced by radiolysis of water and usable for the treatment of dissolving fines and plutoniferous waste.To this end, contacting takes place in a reactor (1) of solid products containing PuO.sub.2 coming from the hopper (5) with an aqueous nitric solution (3) irradiated by radiation or charged particles for producing OH.sup.- radicals by radiolysis of said solution, in the presence of a reagent such as N.sub.2 O, able to trap the solvated electrons and the H.sup.- radicals produced in simultaneous manner and optionally a redox mediator such as silver.Irradiation can take place by an alpha or beta emitter present in the solution or by an external source such as an irradiator or an electron accelerator.Type: GrantFiled: March 5, 1993Date of Patent: June 6, 1995Inventor: Charles Madic
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Patent number: 5419880Abstract: A controlled multi-stage process for the stripping of uranium includes the introduction at one end of a solvent extraction device a uranium loaded organic solution. A concentrated stripping acidic aqueous solution is introduced at the other end of the solvent extraction device so that the aqueous solution and the organic solution are contacted counter-currently in the solvent extraction device at a temperature not substantially exceeding 35.degree. C.Type: GrantFiled: October 8, 1993Date of Patent: May 30, 1995Assignee: Falconbridge, Ltd.Inventors: Richard C. Swider, Steven A. Webster
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Patent number: 5419881Abstract: In a process for treating dissolution residues which are generated in the recovery of fission products, particularly fission molybdenum, wherein nuclear fuel comprising the elements uranium, silicium and aluminum is irradiated and subsequently treated with an alkaline solution from which any dissolution residues are separated, the dissolution residues are dissolved in an additional hydrogen peroxide containing solution to which an acid and iodine or an iodine compound is added whereby a complete dissolution of the residues is achieved.Type: GrantFiled: July 11, 1994Date of Patent: May 30, 1995Assignee: Kernforschungszenlrum Karlsruhe GmbHInventors: Sameh, Abdel H. A., Anne Bertram-Berg
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Patent number: 5384105Abstract: The process for recovering Ta/Nb values from highly flourinated ore materials by the process of;(a) contacting the materials with one or a mixture of HNO.sub.3 or HCl, and H.sub.3 BO.sub.3 wherein the H.sub.3 BO.sub.3 to other acid molar ratio is from about 1/10 to about 1/1,(b) maintaining the temperature between about 55 C. and about 85 C.,(c) reacting for a sufficient period to substantially solubilize the major portion of the materials and to substantially insolubilize all Ta/Nb values, and(d) separating the solids containing the Ta/Nb values from solution.Type: GrantFiled: November 15, 1993Date of Patent: January 24, 1995Assignee: Eco Tek, Inc.Inventor: Bryan L. Carlson
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Patent number: 5368829Abstract: Radioactive metal is recovered from solid oxides of the metal by exposing the oxide to a cocurrent flow of a first acid solution in a first contactor to form partially reacted oxides and a solution containing the metal. The first solution containing the metal is drawn off and the partially reacted oxides are passed through a countercurrent flow of a second acid solution in a second contactor to form reaction residues and a second solution containing the metal. The second solution containing the metal is drawn off and the reaction residues are passed through a countercurrent flow of wash water in a third contactor. The reaction residues are then separated from the wash water and dried.Type: GrantFiled: September 9, 1993Date of Patent: November 29, 1994Assignee: Westinghouse Electric CorporationInventor: Ronald O. Noe
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Patent number: 5340505Abstract: A method for dissolving radioactively contaminated surfaces of metal articles using a reagent of HBF.sub.4 acid with the addition of at least one oxidation agent, preferably hydrogen peroxide H.sub.2 O.sub.2, for the efficient decontamination of radioactively contaminated metal articles. An optimum mixture of this reagent was about 5% HBF.sub.4 acid with the addition of about 0.5% by volume of H.sub.2 O.sub.2. Radioactively contaminated lead plates, for example, were treated by this reagent, and the contaminated solution was used as an electrolyte without any further additive. The contaminated lead or lead oxide is deposited at the anode or cathode decontaminating the solution which may be returned to the process. If, instead of lead, the metal is copper, nickel, steel, silver or mercury or their alloys, the method for dissolving radioactively contaminated surfaces can be executed in the same way with the same reagent.Type: GrantFiled: August 16, 1991Date of Patent: August 23, 1994Assignee: Recytec SAInventors: Jozef Hanulik, Jean-Francois Equey
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Patent number: 5250273Abstract: A process and apparatus for leaching metal values from a particulate mineral ore containing metal values employs a fluidized bed of the particles; a leaching agent solution containing dissolved oxygen flows upwardly of the bed in a lower leaching zone, to an upper clarification zone; a velocity profile is maintained to promote settling of particles so that the particulate solids remain in the leaching zone and a clarified leachant-containing liquid low in suspended solids rises and collects in the clarification zone; the process is carried out with a minimum of undissolved gas and avoids the need for mechanical agitation, but the kinetics of the chemical leaching reaction is improved and heat loss via escaping gases is avoided.Type: GrantFiled: August 27, 1992Date of Patent: October 5, 1993Assignee: Canadian Liquid Air Ltd - Air Liquide Canada LTEEInventors: Derek Hornsey, Robert G. H. Lee
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Patent number: 5205999Abstract: A process for the treatment of a material which is or is suspected to contain or carry one or more actinides or compounds thereof to dissolve such actinides or compounds comprises contacting the material with an aqueous solution having a pH in the range 5.5 to 10.5 which is free of heavy metal ions and comprises ingredients which are naturally degradable to non-toxic products with or without mild physical assistance such as heat or ultra-violet radiation, said solution comprising:(a) carbonated water;(b) a conditioning agent;and (c) a complexing agent which comprises the anion of a carboxylic acid having from 2 to 6 carbon atoms.The process may be employed to separate spent nuclear fuel from its metal containment or it may be employed to decontaminate surface, e.g. concrete or soil or pipes carrying traces of actinides, or bulk materials such as soil or rubble.Type: GrantFiled: September 18, 1991Date of Patent: April 27, 1993Assignee: British Nuclear Fuels plcInventors: John S. Willis, David A. White
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Patent number: 5154899Abstract: A method for recovering plutonium and other metals from materials by leaching comprising the steps of incinerating the materials to form a porous matrix as the residue of incineration, immersing the matrix into acid in a microwave-transparent pressure vessel, sealing the pressure vessel, and applying microwaves so that the temperature and the pressure in the pressure vessel increase. The acid for recovering plutonium can be a mixture of HBF.sub.4 and HNO.sub.3 and preferably the pressure is increased to at least 100 PSI and the temperature to at least 200.degree. C. The porous material can be pulverized before immersion to further increase the leach rate.Type: GrantFiled: June 28, 1991Date of Patent: October 13, 1992Inventor: Edward F. Sturcken
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Patent number: 5135728Abstract: A process for dissolving plutonium, and in particular, delta-phase plutonium. The process includes heating a mixture of nitric acid, hydroxylammonium nitrate (HAN) and potassium fluoride to a temperature between 40.degree. and 70.degree. C., then immersing the metal in the mixture. Preferably, the nitric acid has a concentration of not more than 2M, the HAN approximately 0.66M, and the potassium fluoride 0.1M. Additionally, a small amount of sulfamic acid, such as 0.1M can be added to assure stability of the HAN in the presence of nitric acid. The oxide layer that forms on plutonium metal may be removed with a non-oxidizing acid as a pre-treatment step.Type: GrantFiled: January 3, 1992Date of Patent: August 4, 1992Inventor: David G. Karraker
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Patent number: 5085834Abstract: A method for separating plutonium from uranium and from fission products with the aid of crown ether compounds comprising contacting an aqueous solution A0 containing Pu, U and fission products with an organic solvent O0 containing at least one crown ether compound to obtain an organic solution O1 containing Pu and U; extracting U from the organic solution O1 with an aqueous solution A4 such as water or nitric acid to obtain an aqueous solution A5 containing U and an organic solution O3 containing mainly of Pu and recovering Pu from the organic solution using an aqueous solution A6 such as sulfuric acid.Type: GrantFiled: December 11, 1990Date of Patent: February 4, 1992Assignee: Cogema-Compaignie Generale des Matieres NucleairesInventors: Marc Lemaire, Alain Guy, Jacques Foos, Rodolphe Chomel, Pierre Doutreluigne, Thierry Moutarde, Vincent Guyon, Henri Le Roy
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Patent number: 5084253Abstract: A method of removing niobium from a uranium-niobium alloy includes dissolving the uranium-niobium alloy metal pieces in a first aqueous solution containing an acid selected from a group consisting of HCl and H.sub.2 SO.sub.4 and a fluoboric acid as a catalyst to provide a second aqueous solution which includes uranium (U.sup.+4), acid radical ions, the acids and insolubles including uranium oxides and niobium oxides; adding nitric acid to the insolubles to complete the oxidation of the niobium oxides to yield niobic acid and further solubilizing thr uranium oxide; and separating the niobic acid, nitric acid and solubilized uranium oxides.Type: GrantFiled: November 13, 1989Date of Patent: January 28, 1992Assignee: Nuclear Metals, Inc.Inventors: Eugene N. Pollock, David S. Schlier, George Shinopulos
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Patent number: 5057289Abstract: A process for the separation of uranium and plutonium as well as fission ducts including technetium from a nitric acid feed solution (fuel solution) in which said solution is treated with an extraction agent in an organic solvent to charge said agent with U, Pu and fission products including technetium by the counterflow process. The charged extraction agent containing U, Pu and fission products including technetrium is treated with a washing solution and subsequently with a reducing agent for the separation of the uranium from the plutonium and from fission products including technetium not previously washed out. To improve the separation of uranium and obtain a cleaner uranium end product, the treatment of the organic solvent containing said charged agent with reducing agent is effected in one or more stages by the crossflow process instead of by the counterflow process.Type: GrantFiled: March 9, 1989Date of Patent: October 15, 1991Assignee: Deutsche Gesellschaft fur Wideraufarbeitung von Kernbrennstoffen mbHInventors: Wolfgang Issel, Werner Knoch, Hartmut Ramm
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Patent number: 5028402Abstract: Process for separating plutonium from uranium contained in a nitric acid aqueous solution from the reprocessing of irradiated fuels comprising plutonium, uranium and fission products by means of crown ethers. Nitric acid aqueous solution (5) containing plutonium, uranium and fission products is contacted at (2) with an organic liquid membrane (3) containing a crown ether. The uranium and plutonium are extracted in the liquid membrane (3) and then transferred by said membrane into a receiving solution (7), which becomes enriched with uranium, because the latter is transferred more rapidly than the plutonium. The crown ether can be DCH 18 C6 or DB 18 C6.Type: GrantFiled: June 16, 1989Date of Patent: July 2, 1991Assignee: Cogema Compagnie General des Matieres NucleairesInventors: Jacques Foos, Pierre Epherre, Alain Guy, Marc Lemaire, Rodolph Chomel, Gerard Cauquil, Pierre Patigny, Alain Vian
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Patent number: 5023059Abstract: A metallurgical processing system for economically recovering metal values, such as columbium, tantalum, thorium, and uranium from dilute source solids, such as digestion sludges, by a series of steps including:1) slurrying the source solids with dilute hydrofluoric acid to produce a solid phase and a liquid phase containing dissolved tantalum and columbium, then extracting tantalum and/or columbium from the liquid phase by means of a liquid ion-exchange process and then, additionally;2) roasting the solid phase with sulfuric acid to recover and recycle hydrofluoric acid, leaching the roasted solids with dilute sulfuric acid to produce a disposable solid phase and a liquid phase containing thorium and uranium, and extracting thorium and uranium from the liquid phase by means of a liquid-liquid amine extraction process.Type: GrantFiled: November 2, 1988Date of Patent: June 11, 1991Inventors: Edwin J. Bielecki, Karl A. Romberger, Bart F. Bakke, Martin A. Hobin, Charles R. Clark
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Patent number: 5008044Abstract: Contaminated surface layers are decontaminated by treatment with an aqueous fluorine base-containing decontamination solution. The aqueous decontamination solution contains 0.05 to 50 Mol of decontamination agent per liter, and the decontamination agent preferably comprises at least one substance from the group colon hexafluorosilicate acid, fluoroboric acid, and the salts of both of these. The decontamination solution produces the required high decontamination factors on metallic substances and brickworks as well. The used decontamination solution can, after regeneration, be recycled into the decontamination process.Release of decontaminated material by dissolution of the surface layer of the decontaminated objects provides decontamination of objects having complicated and hard-to-measure geometries.The decontamination agent (HBF.sub.4 -acid) is advantageously produced from contaminated boric acid from pressurized water reactor wastes by reaction with fluoride or hydrofluoric acid. The HBF.sub.Type: GrantFiled: May 9, 1989Date of Patent: April 16, 1991Assignee: Recytec SAInventor: Jozef Hanulik
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Patent number: 4968504Abstract: The separation of uranium, iron and scandium is achieved by the following process wherein a material containing these values is dissolved in mineral acid to form an aqueous solution, thereafter, an iminodiacetic acid cationic ion exchange resin is used to retain a major portion of the scandium and uranium. A raffinate containing the iron is formed. The ion exchange resin having said scandium and uranium retained thereon is rinsed with a dilute acid to remove residual metals other than scandium and uranium. The resin is eluted with an aqueous solution of an organic chelating acid to remove a major portion of the scandium from said resin and to form an aqueous solution containing scandium. The resin is then eluted with an aqueous solution of a mineral acid to remove a major portion of the uranium from the resin to form an aqueous solution containing the uranium. The scandium and uranium are recovered as solids.Type: GrantFiled: October 19, 1989Date of Patent: November 6, 1990Assignee: GTE Laboratories IncorporatedInventor: William J. Rourke
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Patent number: 4933113Abstract: Contaminated surface layers are decontaminated by treatment with an aqueous fluorine base-containing decontamination solution. The aqueous decontamination solution contains 0.05 to 50 Mol of decontamination agent per liter, and the decontamination agent preferably at least one substance from the group: hexafluorosilicate acid, fluoroboric acid, and the salts of both of these. The decontamination solution produces the required high decontamination factors on pressurized water reactors, boiling water reactors, metallic substances, high temperature alloys and brickworks as well. The used decontamination solution can, after regeneration, by recycled into the decontamination process. Release of decontaminated material by dissolution of the surface layer of the decontaminated objects provides decontamination of objects having complicated and hard-to-measure geometries. The decontamination agent (NBF.sub.Type: GrantFiled: May 9, 1989Date of Patent: June 12, 1990Assignee: Recytec SAInventor: Jozef Hanulik
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Patent number: 4923639Abstract: Method for treating plutonium and/or uranyl nitrate by superheating and concentrating a nitric acid starting solution, characterized by the feature that nitric acid starting solution is concentrated to form a Pu(VI)-and/or U(VI)-containing nitrate melt, is poured into a mold, is solidified by cooling down, and is transported and/or stored as a solidified solid body until further processing.Type: GrantFiled: January 15, 1982Date of Patent: May 8, 1990Assignee: Alkem GmbHInventors: Wolfgang Stoll, Christian Ost, Volker Schneider
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Patent number: 4892715Abstract: Mineral values, particularly uranium, are recovered from ground mineral-containing ore by contacting the ground ore with an oxidizing gas and leaching with an acidic or alkaline leach solution. The oxidizing gas treatment significantly increases minerals recovery and/or significantly reduces the severity of the conditions required, particularly the temperature and the concentration of leach chemicals. Further improvements are attained by separating a total ore into a coarse fraction and a fines fraction and separately treating at least a part of these two fractions. The sequence of operations, i.e., treating with oxidizing gas and leaching, the manner of leaching and the conditions of leaching are varied to obtain significantly improved results, based on the discoveries that a coarse fraction is substantially easier to leach than the total ore or the fines fraction and treatment with an oxidizing gas significantly improves the ease of leaching, particularly of the fines fraction.Type: GrantFiled: December 20, 1982Date of Patent: January 9, 1990Assignee: Phillips Petroleum CompanyInventor: Robert L. Horton
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Patent number: 4885098Abstract: An elastic bar member is coupled to an orbiting mass oscillator and the entire assembly is suspended from a cable or the like such that the bar member has freedom of lateral motion and is nakedly immersed in a slurry having particulate material contained therein such as a mineral ore reject from which metal has been extracted. The rotor of the orbiting mass oscillator is driven at a speed such as to generate cycloidal sonic energy in the bar preferably at a frequency such as to set up resonant standing wave vibration of the bar in a cycloidal quadrature pattern. The cycloidal vibrational energy tends to set the surrounding fluid material into a whirling rotation or rotary traveling wave which facilitates the agglomeration or coagulation of the particles in the material and enhances the settling operation to make for more complete separation of the particles from the liquid.Type: GrantFiled: October 21, 1988Date of Patent: December 5, 1989Inventor: Albert G. Bodine
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Patent number: 4883532Abstract: An elastic bar member is clamped to an orbiting mass oscillator and the entire assembly is suspended from a cable or the like such that the bar member has freedom of lateral motion and is nakedly immersed in a leachant having a material contained therein such as a mineral ore from which metal is to be extracted. The rotor of the orbiting mass oscillator is driven at a speed such as to generate cycloidal sonic energy in the bar preferably at a frequency such as to set up resonant standing wave vibration of the bar in a cycloidal nutating pattern. The cycloidal vibrational energy tends to set the surrounding fluid material into a whirling rotation or rotary traveling wave which facilitates the mixing of the ore and leachant and enhances the leaching operation to make for more complete separation of the mineral from the ore.Type: GrantFiled: July 22, 1988Date of Patent: November 28, 1989Inventor: Albert G. Bodine
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Patent number: 4880607Abstract: Mineral values, particularly uranium, are recovered from mineral containing ore by separating the ore into a coarse fraction and a fines fraction, adding a diluent solid material, such as a portion of barren coarse fraction to the fines fraction and leaching the thus diluted fines fraction with a leach solution. The coarse fraction is separately leached, preferably under mild conditions of temperature and leach solution concentration. In another aspect, the total ore is leached, preferably under mild conditions, the thus leached ore is separated into a coarse fraction and a fines fraction, the fines fraction is again leached and at least a part of the leached fines fraction from the second leach step is recycled to the first leach step.Type: GrantFiled: December 20, 1982Date of Patent: November 14, 1989Assignee: Phillips Petroleum CompanyInventors: Robert L. Horton, George V. Lakey
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Patent number: 4874599Abstract: A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag containing the same and having a radioactivity level of at least about 7000 pCi/gm. The slag is ground to a particle size of about 200 microns or less. The ground slag is contacted with an acid under certain prescribed conditions to produce a liquid product and a particulate solid product. The particulate solid product is separated from the liquid and treated at least two more times with acid to produce a solid residue consisting essentially of magnesium fluoride substantially free of uranium and having a residual radioactivity level of less than about 1000 pCi/gm. In accordance with a particularly preferred embodiment of the invention a catalyst and an oxidizing agent are used during the acid treatment and preferably the acid is sulfuric acid having a strength of about 1.0 Normal.Type: GrantFiled: November 14, 1985Date of Patent: October 17, 1989Assignee: Rockwell International CorporationInventors: Richard L. Gay, Donald E. McKenzie
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Patent number: 4839103Abstract: Not readily dissolvable nuclear fuel is dissolved in an airtight closed vessel or autoclave. Nitric acid is evaporated and condensed in the vessel and the nitric acid condensate trickles over the nuclear fuel disposed outside of the nitric acid undergoing evaporation.Type: GrantFiled: January 21, 1987Date of Patent: June 13, 1989Assignee: Alkem GmbHInventors: Michael Steinhauser, Gunter Hoffmann, Fritz Weigel, deceased, Kurt Wittmann, Dieter Schafer
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Patent number: 4837375Abstract: A method and apparatus are provided for producing green salt (UF.sub.4) from uranium-bearing metal pieces. The uranium-bearing metal pieces are dissolved in a first aqueous solution containing hydrochloric acid and between 0.5% and 5% fluoboric acid to provide a second aqueous solution which includes uranium (U.sup.+4), chlorine ions (Cl.sup.-) and hydrochloric and fluoboric acids. Hydrofluoric acid is added to the second aqueous solution to precipitate green salt out of that solution and provide a third aqueous solution which contains hydrochloric acid. The green salt is then separated from the third aqueous solution.Type: GrantFiled: January 20, 1987Date of Patent: June 6, 1989Assignee: Nuclear Metals, Inc.Inventor: Eugene N. Pollock
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Patent number: 4828759Abstract: Contaminated surface layers are decontaminated by treatment with an aqueous fluorine base-containing decontamination solution. The aqueous decontamination solution contains 0.05 to 50 Mol of decontamination agent per liter, and the decontamination agent preferably comprises at least one substance from the group, hexafluorosilicate acid, fluoroboric acid, and the salts of both these. The decontamination solution produces the required high decontamination factors on metallic substances and brickworks as well. The used decontamination solution can, after regeneration, be recycled into the decontamination process.Release of decontaminated material by dissolution of the surface layer of the decontaminated objects provides decontamination of objects having complicated and hard-to-measure geometries.The decontamination agent (HBF.sub.4 -acid) is advantageously produced from contaminated boric acid from pressurized water reactor wastes by reaction with fluoride or hydrofluoric acid. The HBF.sub.Type: GrantFiled: January 28, 1987Date of Patent: May 9, 1989Inventor: Jozef Hanulik
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Patent number: 4793978Abstract: A method and apparatus are provided for producing uranyl peroxide (UO.sub.4.2H.sub.2 O) from uranium-bearing metal pieces. The uranium-bearing metal pieces are dissolved in a first aqueous solution containing nitric acid and between 0.5% and 5.0% fluoboric acid to provide a second aqueous solution which includes uranyl ions (UO.sub.2.sup.+2) and nitric and fluoboric acids. Hydrogen peroxide is added to the second aqueous solution to precipitate uranyl peroxide out of that solution and provide a third aqueous solution which contains nitric and fluoboric acids. The uranyl peroxide is then separated from the third aqueous solution.Type: GrantFiled: January 20, 1987Date of Patent: December 27, 1988Assignee: Nuclear Metals, Inc.Inventor: Eugene N. Pollock
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Patent number: 4780138Abstract: An elastic bar member is clamped to an orbiting mass oscillator and the entire assembly is suspended from a cable or the like such that the bar member has freedom of lateral motion and is nakedly immersed in a leachant having a material contained therein such as a mineral ore from which metal is to be extracted. The rotor of the orbiting mass oscillator is driven at a speed such as to generate cycloidal sonic energy in the bar preferably at a frequency such as to set up resonant standing wave vibration of the bar in a cycloidal nutating pattern. The cycloidal vibrational energy tends to set the surrounding fluid material into a whirling rotation or rotary traveling wave which facilitates the mixing of the ore and leachant and enhances the leaching operation to make for more complete separation of the mineral from the ore.Type: GrantFiled: December 3, 1987Date of Patent: October 25, 1988Inventor: Albert G. Bodine
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Patent number: 4764353Abstract: Uranium is leached from water slurries of uranium ore by incorporating a mixture of sulfur dioxide and air therein to provide the oxidizing and acidifying requirements to accomplish leaching.Type: GrantFiled: May 20, 1982Date of Patent: August 16, 1988Assignee: Inco LimitedInventors: Juraj Babjak, Eberhard Krause
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Patent number: 4749519Abstract: The invention relates to a process for recovering the plutonium contained in the solid waste, such as process, technological and laboratory waste.The waste is contacted with aqueous nitric acid solution having a nitric acid concentration of 2 to 8 mole/l, which contains a compound of Ag.sup.2+ soluble in the solution, for oxidizing the plutonium present in the waste and for dissolving same in the nitric solution.Preferably, contacting takes place in an electrolytic cell having an anode and a cathode, by applying a potential difference between anode and cathode which is sufficient to continuously regenerate the Ag.sup.2+ ions used for oxidizing the elements present in said waste.Type: GrantFiled: May 7, 1987Date of Patent: June 7, 1988Assignee: Commissariat a l'Energie AtomiqueInventors: Gerard Koehly, Jacques Bourges, Charles Madic, Michael Lecomte
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Patent number: 4705672Abstract: The present invention is directed to a process to improve the suspended solids removal by the filter cloth used in the clarification of leached uranium ore, comprising contacting the filter cloth with an effective amount of an acrylamide polymer.Type: GrantFiled: April 28, 1986Date of Patent: November 10, 1987Assignee: Calgon CorporationInventors: John W. McCurdy, Brian H. Danyliw
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Patent number: RE34613Abstract: Contaminated surface layers are decontaminated by treatment with an aqueous fluorine base-containing decontamination solution. The aqueous decontamination solution contains 0.05 to 50 Mol of decontamination agent per liter, and the decontamination agent preferably comprises at least one substance from the group.Iadd.: .Iaddend..[.colon.]. hexafluorosilicate acid, fluoroboric acid, and the salts of both of these. The decontamination solution produces the required high decontamination factors on metallic substances and brickworks as well. The used decontamination solution can, after regeneration, be recycled into the decontamination process.Release of decontaminated material by dissolution of the surface layer of the decontaminated objects provides decontamination of objects having complicated and hard-to-measure geometries.The decontamination agent (HBF.sub.4 -acid) is advantageously produced from contaminated boric acid from pressurized water reactor wastes by reaction with fluoride or hydrofluoric acid.Type: GrantFiled: November 25, 1991Date of Patent: May 24, 1994Assignee: Recytec SAInventor: Jozef Hanulik