Abstract: Metals such as iron, uranium, vanadium, molybdenum and rare earths are reduced to lower oxidation states in various acid media using silicon metal or an iron-silicon alloy. In particular, ferric iron and hexavalent uranium in wet-process phosphoric acid are reduced to the ferrous and tetravalent states, respectively, using silicon metal or an iron-silicon alloy to provide a feed acid which is suitable for extraction with an extractant which is selective for tetravalent uranium such as a mixture of mono- and di-(alkylphenyl) esters of orthophosphoric acid.

Abstract: Uranium ores, concentrates, calcines or tailings are processed to remove radium and thorium as well as uranium. Selected ores, concentrates or tailings, or if more appropriate, chlorination calcines thereof, are leached by selected aqueous chlorine-containing media (preferably in two stages) until uranium, radium and thorium are substantially all dissolved, with the insoluble residual solids being suitable for disposal. The leach solution is treated to recover sequentially uranium, usually thorium, and radium by selected techniques. The radium recovered can be disposed of in any environmentally-acceptable manner. The amount of iron in the residual leach liquor should be controlled to avoid iron build-up, with the barren leach solution being suitable for recycle.

Abstract: The invention concerns a process for the recovery of the uranium contained in an impure phosphoric acid. The impure acid is treated with an organic phase capable of extracting U (VI), and the resultant organic phase is then re-extracted with an aqueous solution containing complexing acid and an oxidizing-reducing agent in the reduced state, said oxidizing-reducing agent being capable of reducing U.sup.+6 to U.sup.+4 in said aqueous solution. The resultant aqueous phase is then subjected to electrochemical oxidation, followed by extraction with a second organic phase from which the uranium is recovered, the depleted aqueous solution being recycled to the re-extraction after electrochemical reduction, with the process comprising two organic phase cycles and a cycle of a complexing aqueous solution.The process is of particular interest when applied to the recovery and concentration of uranium contained in a wet process phosphoric acid.

Abstract: Uranium in wet-process phosphoric acid in the tetravalent state is extracted with a mixture of mono- and di-(alkylphenyl) esters of orthophosphoric acid containing a phenol modifier such as nonylphenol or octylphenol.

Abstract: A process for removing arsenic from an aqueous solution containing arsenic in the form of a soluble arsenate includes adjusting the pH of the solution if necessary to at least about 10, adding a soluble barium salt to precipitate arsenic as barium arsenate, and removing the precipitated barium arsenate from the solution.

Abstract: Nuclear fuel processing solution consisting of tri-n-butyl phosphate and dodecane, with a complex of uranium, plutonium, or zirconium and with a solvent degradation product such as di-n-butyl phosphate therein, is contacted with an aqueous solution of a salt formed from hydrazine and either a dicarboxylic acid or a hydroxycarboxylic acid, thereby removing the aforesaid complex from the processing solution.

Abstract: Controlling the uranium extraction coefficient in uranium extraction processes involving wet process phosphoric acid feed is accomplished by monitoring the oxidation potential of the raffinate acid stream exiting the extractor, and maintaining the oxidation potential of the raffinate at a value above 350 mV.

Abstract: The invention relates to a process for the recovery and the concentration of uranium (VI) contained in an organic phase. The organic phase is treated continuously in a contact zone with an aqueous solution containing an oxidizing-reducing agent in the reduced state, said oxidizing-reducing agent being capable of reducing U.sup.+6 to U.sup.+4 in said aqueous solution. The aqueous solution employed in the process issues in part or in its entirety from the cathodic compartment of an electrolytic separation cell, which is under a direct current potential, and the aqueous phase issuing from the contact zone feeds in part or in its entirety the anodic compartment of the electrolytic cell. The process is of particular interest when applied to the recovery and concentration of uranium contained in a wet process phosphoric acid.

Abstract: Process for the recovery of the uranium present in a phosphoric acid solution by bringing the said solution into contact with an organic solvent suitable for extracting the uranium, wherein the said organic solvent comprises a system of extractants constituted by an acid organophosphorus compound having at least one sulphur atom and by a neutral phosphine oxide of formula: ##STR1## in which R.sub.1, R.sub.2 and R.sub.3 are identical or different alkyl, alkoxyalkyl or aryl radicals.

Abstract: A process for removing a species from a fluid which comprises (a) contacting said fluid with an emulsion, said emulsion having an external phase and an internal phase, said external phase being immiscible with said fluid and said species being permeable to said external phase; (b) permeating said species through said external phase into said internal phase; (c) converting said permeated species in said internal phase, into a species which is impermeable to said external phase; (d) separating said emulsion from said fluid; (e) converting the impermeable species of step (c) into a species which is permeable to said external phase by means of an oxidation-reduction reaction; and (f) permeating the permeable species of step (e) through said external phase. The instant process may be carried out in the reverse manner, i.e. the fluid including the species to be removed can be the internal phase of an emulsion or foam and thus permeate through the external phase.

Abstract: A process to restore solvent after the stripping step in recovering uranium from phosphoric acid, comprises passing stripped, water-immiscible organic extraction solvent, containing contaminants and having a lowered uranium extraction coefficient value, through a water scrub, to scrub contaminants from the organic solvent and raise its uranium extraction coefficient. The scrubbed solvent is then passed back to the extractor and the contaminated water is passed into at least one purification means and then back to the scrubber.

Abstract: A method of stabilizing wet process phosphoric acid containing acid soluble impurities preparatory to solvent extraction for the recovery of valuable minerals. The acid is introduced into a vessel containing crystal seed bed of the impurities. A portion of the acid then is withdrawn and concentrated to effect supersaturation of the impurities contained therein. The supersaturated acid is returned to the vessel to mix with the remaining solution and cause additional impurities to precipitate. Thereafter, a portion of the solution, containing precipitated impurities, is withdrawn and introduced into a separator. In the separator, the solution is separated into an essentially solids-free stream containing unprecipitated soluble impurities and a solids-containing stream.

Abstract: The precipitation of an iron complex is reduced during the stripping of uranium with ferrous ion, where the uranium was oxidized with nitric acid then extracted with an organic solvent. The reduction is accomplished by pre-stripping with sufficient ferrous ion to reduce nitrates and nitrites formed during the nitric acid oxidation. The amount of ferrous ion used in pre-stripping, however, is insufficient to precipitate uranium.

Abstract: An improved liquid-liquid solvent extraction system is provided having a mixing stage which includes a mixing device for creating a dispersion of the two liquid phases followed by a residence chamber designed to enhance contacting and mass transfer between the solute and solvent phases. The separating stage includes a drop size conditioning device which establishes a drop size in the discontinuous liquid phase of the dispersion which can be separated easily from the continuous liquid phase in the succeeding settling stage of the device. The drop size conditioning device also acts to reduce entrainment of the solvent phase in the solute phase during separation of the phases. The settling device may contain a series of baffles to reduce the time required for phase separation and to reduce entrainment of the solvent phase in the solute phase.The system is used to extract metal ions such as uranium, copper, cobalt, nickel, and vanadium from aqueous process streams containing dilute concentrations of such ions.

Abstract: Wet process phosphoric acid is oxidized with nitric acid so that uranium values therein are in the +6 state. The organic extractant which contacts the acid extracts the +6 uranium and nitrate and/or nitrite ions. Urea is added to the oxidized acid to react with the nitrate and/or nitrite ions so that the organic does not extract them. The organic is reductively stripped with an aqueous solution containing ferrous ions. The efficacy of the ferrous ions is not lost through reaction with nitrate and/or nitrite ions.

Abstract: A compound of the formula: ##STR1## wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO.sub.3 H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes.

Abstract: A metal containing acidic solution, also containing humic acid impurities and contaminants, is purified by contacting the acidic solution with a scrubbing agent consisting essentially of a metal extractant and from about 50 vol.% to about 90 vol.% of a hydrocarbon, where the scrubbing agent interacts with impurities and contaminants in the acidic solution to form a sludge phase which is removed and a purified acid phase which can be fed into a metal recovery process.

Abstract: A compact, multi-stage, co- or counter-current liquid-liquid extraction apparatus includes first and second mixer-settlers which share a common wall. Each of the first and second mixer-settlers comprises a mixing chamber having an agitator mounted therein, upper and lower settling chambers, and upper and lower baffles between the mixing chamber and the upper and lower settling chambers respectively. The liquid media to be contacted in each mixer-settler are supplied to the mixing chamber from which dispersion flows upwardly and downwardly into the upper and lower baffles. Disengaged lighter medium flows out from the upper settling chamber to the mixer-settler, over a weir whose length exceeds half the length of the common wall, while disengaged heavier medium flows out of the lower settling chamber of one mixer-settler to the corresponding mixing chamber of the next mixer-settler. In one form the disengaged heavier medium also overflows a corresponding outlet weir to pass on to the next mixer-settler.

Abstract: Electrostatic separation of aqueous and particulate matter from a primarily organic impurities phase which forms at the organic/aqueous interface in a liquid-liquid extraction process.

Abstract: In the process of uranium recovery from wet-process phosphoric acid, post treatment of the raffinate phosphoric acid is very important to prevent damage to the rubber linings of the acid evaporators and to recover the solvent for reuse. A simple and continuous method using an inclined parallel-corrugated-plate separator to remove the organic solvent entrainment from the raffinate phosphoric acid is established herein.

Abstract: A liquid membrane process for removing ions from solution which comprises contacting a solution containing a first ion and a second ion with an emulsion, said emulsion comprising an external phase which is immiscible with said solution and contains a first complexing agent, and a second complexing agent, said first complexing agent being capable of forming a first complex with said first ion, and said second complexing agent being capable of forming a second complex with said second ion, both of said complexes being soluble in said external phase, and an internal phase, which comprises a (1) decomplexing agent, said decomplexing agent being capable of converting said first complex into said first complexing agent and said first ion and (2) an inhibiting agent which is capable of inhibiting the formation of said first complex, whereby the first ion diffuses from said solution into said internal phase, and said second ion diffuses from said solution into said external phase.

Abstract: A method and apparatus for processing spent nuclear reactor fuel wherein plutonium is continuously contaminated with radioactive fission products and diluted with uranium. Plutonium of sufficient purity to fabricate nuclear weapons cannot be produced by the process or in the disclosed reprocessing plant. Diversion of plutonium is prevented by radiation hazards and ease of detection.

Abstract: Certain metals, and especially uranium, are recovered from an organic solvent by stripping with an aqueous solution containing polymeric phosphates under conditions in which the polymeric phosphate does not quickly hydrolize and metal preferentially dissolves in the aqueous solution. The metal may then be recovered from the aqueous solution by hydrolizing the polymeric phosphates and either precipitating the metal or reextracting the metal at higher concentrations with an organic solvent containing extractants.

Abstract: A process for transfer by extraction, of at least one species from a fluid phase to a first liquid phase receptive to such species, comprises intimately contacting the fluid phase with an emulsion of the first liquid phase in a second liquid phase which is permeable with respect to such species and substantially immiscible in the first liquid phase. The emulsion is stabilized by the second liquid phase containing at least one substantially insoluble particulate solid which is substantially non-reactive to constituents contained in each of such phases in an amount sufficient to form a stable emulsion. Transfer of the species is from the fluid phase through the second solids--containing liquid phase to the first liquid phase.In one embodiment, the first liquid phase is lean with respect to the species to be extracted. In another embodiment, mass action is utilized to maintain a driving force by counter-transport of a different ion.

Abstract: A process for transfer by extraction, of at least one species from a fluid phase to a first liquid phase receptive to such species, comprises intimately contacting the fluid phase with an emulsion of the first liquid phase in a second liquid phase which is permeable with respect to such species and substantially immiscible in the first liquid phase. The emulsion is stabilized by the second liquid phase containing at least one substantially insoluble particulate solid which is substantially non-reactive to constituents contained in each of such phases in an amount sufficient to form a stable emulsion. Transfer of the species is from the fluid phase through the second solids-containing liquid phase to the first liquid phase.In one embodiment, the first liquid phase is lean with respect to the species to be extracted. In another embodiment, mass action is utilized to maintain a driving force by counter-transport of a different ion.

Abstract: A compact, multi-stage, co- or counter-current liquid-liquid extraction apparatus is described having two or more stages. Each stage lies adjacent at least one other stage and comprises a mixing chamber having an agitator mounted therein, upper and lower settling chambers, and upper and lower bafffles between the mixing chamber and the upper and lower settling chambers respectively. Vertical partitions at the corners of each stage strengthen the structure and divide off preferably triangular compartments which act as downcomers or risers as appropriate for the liquid media. The liquid media to be contacted in each stage are supplied to the mixing chamber from which dispersion flows upwardly and downwardly into the upper and lower baffles. Disengaged lighter medium flows out from the upper settling chamber over a weir to the next stage, while disengaged heavier medium flows out of the lower settling chamber of one stage to the corresponding next stage.

Abstract: A method of preparing uranium (VI) peroxide hydrate from uranium tetrafluoride hydrate, comprising the steps of digesting uranium tetrafluoride hydrate in an aqueous acid in the presence of a fluoride complexing agent to produce an aqueous uranium solution, adjusting the aqueous uranium solution to a pH between about 1 to about 3, filtering the aqueous uranium solution to remove undissolved material, reacting the aqueous uranium solution with peroxide to precipitate uranium (VI) peroxide hydrate, and separating the precipitated uranium (VI) peroxide hydrate.

Abstract: A method of preparing uranium (VI) peroxide hydrate from uranium tetrafluoride hydrate, comprising the steps of digesting uranium tetrafluoride hydrate in an aqueous acid in the presence of a fluoride precipitating agent to produce an aqueous uranium solution, filtering the aqueous uranium solution to remove precipitated fluorides and undissolved material, adjusting the aqueous uranium solution to a pH between about 1 to about 3, reacting the aqueous uranium solution with peroxide to precipitate uranium (VI) peroxide hydrate, and separating the precipitated uranium (VI) peroxide hydrate.

Abstract: Impure phosphoric acid containing uranium values is pretreated with a water immiscible organic sulfonic acid, preferably in conjunction with a water immiscible organic acid phosphate compound, for extraction of ionic metallic impurities and organic impurities to produce pretreated phosphoric acid containing uranium values. Pretreated phosphoric acid is contacted with a water immiscible extractant comprising an organic uranium-extracting agent, preferably an organophosphorus compound, dissolved in a water immiscible organic diluent to produce uranium-depleted phosphoric acid and uranium-enriched extractant. Uranium is recovered from the uranium-enriched extractant.

Abstract: A process for the reductive stripping of an organic phase containing either or both uranium and vanadium. Said process comprising contacting said organic phase containing either or both uranium in the hexavalent state and vanadium in the pentavalent state with an aqueous solution containing a predetermined quantity of trivalent vanadium to reduce either or both the uranium and vanadium to a lower valence state which is not soluble in said organic phase. The reduced uranium and vanadium separate from the organic phase and collect in the aqueous solution from which it may be subsequently recovered. The process of this invention yields an aqueous strip solution containing fewer contaminates comprising undesirable alkali metals such as sodium and the like than other known chemical stripping processes. Further, the process limits the quantity of ferrous ions present in the system to alleviate the problem of sludge formation in subsequent treatment of the wet process acid to produce phosphate fertilizer.

Abstract: Aqueous phosphoric acid, e.g., a slurry of the acid produced by the "wet" process, is contacted with steam under organic volatile-removing conditions to remove volatile organic material. A "wet process" aspect of the process involves contacting crude phosphoric acid produced by the wet process at a temperature, preferably not greater than 100.degree. C., while binding bindable solid impurities present and controlling the density of the acid to avoid deleterously affecting the processing character of the acid. In a first facet of this aspect, humic-extracting extractants are employed to remove humics, and in a second facet, heavy metal-extracting extractants are employed to recover heavy metals, from the acid.

Abstract: A process for rendering actinide values recoverable from sodium carbonate scrub waste solutions containing these and other values along with organic compounds resulting from the radiolytic and hydrolytic degradation of neutral organophosphorous extractants such as tri-n butyl phosphate (TBP) and dihexyl-N,N-diethyl carbamylmethylene phosphonate (DHDECAMP) which have been used in the reprocessing of irradiated nuclear reactor fuels. The scrub waste solution is preferably made acidic with mineral acid, to form a feed solution which is then contacted with a water-immiscible, highly polar organic extractant which selectively extracts the degradation products from the feed solution. The feed solution can then be processed to recover the actinides for storage or recycled back into the high-level waste process stream. The extractant is recycled after stripping the degradation products with a neutral sodium carbonate solution.

Abstract: A method for pretreating phosphoric acid to prevent the formation of a mass of suspended solids (i.e., "crud") during solvent extraction of the acid is described. Prior to solvent extraction, the acid is contacted with a liquid hydrocarbon such as kerosene which collects the crud-forming agents. The mixture of liquid hydrocarbon and collected crud-forming agents is separated from the acid and the liquid hydrocarbon is regenerated for reuse in the first step of the method.

Abstract: A method for handling the problem of crud formation in the solvent extraction of wet-process phosphoric acid is described. Crud is the name ordinarily given to the thick interfacial layer of semi-floatable material which tends to form and accumulate, and which interferes with many of the extraction processes and, in particular, with the solvent extraction of wet-process phosphoric acid. The method described provides for the operation of the solvent extraction stages in a manner that allows the formation and temporary accumulation of crud in those stages whereupon the solvent and the crud are then removed from the extraction stages and treated in a series of operations which include a clarification step, an acid removal step, a water wash step and a caustic treatment step, which steps effectively separate the solvent from the crud, and remove the crud components from the system and regenerate otherwise unusable solvent.

Abstract: A method of recovering uranium from wet-process phosphoric acid wherein the acid is treated with a mixture of an ammonium salt or ammonia, a reducing agent, and then a miscible solvent. Solids are separated from the phosphoric acid liquid phase. The solid consists of a mixture of metal phosphates and uranium. It is washed free of adhering phosphoric acid with fresh miscible solvent. The solid is dried and dissolved in acid whereupon uranium is recovered from the solution. Miscible solvent and water are distilled away from the phosphoric acid. The distillate is rectified and water discarded. All miscible solvent is recovered for recycle.

Abstract: A process for partitioning and recovering actinide values from acidic waste solutions resulting from reprocessing of irradiated nuclear fuels by adding hydroxylammonium nitrate and hydrazine to the waste solution to adjust the valence of the neptunium and plutonium values in the solution to the +4 oxidation state, thus forming a feed solution and contacting the feed solution with an extractant of dihexoxyethyl phosphoric acid in an organic diluent whereby the actinide values, most of the rare earth values and some fission product values are taken up by the extractant. Separation is achieved by contacting the loaded extractant with two aqueous strip solutions, a nitric acid solution to selectively strip the americium, curium and rare earth values and an oxalate solution of tetramethylammonium hydrogen oxalate and oxalic acid or trimethylammonium hydrogen oxalate to selectively strip the neptunium, plutonium and fission product values.

Abstract: A method of resolving oil-in-water emulsions resulting from the organic solvent extraction of uranium from aqueous acidic leach liquors which comprises treating said emulsions in accordance with the following steps:(a) adding to said emulsions a water-in-oil emulsion which contains from 2-50% by weight of a water-soluble acrylamide copolymer which contains from 5-50% by weight of a lower alkyl substituted tertiary aminoethyl methacrylate and quaternary ammonium salts thereof in an amount to provide at least 20 parts per million of the acrylamide copolymer;(b) adjusting the pH of the emulsion being treated with ammonia to at least 9;(c) adding to the ammonia treated emulsion a water-soluble surfactant which is capable of inverting the water-in-oil emulsion which contains the polymer; and then(d) slowly mixing the treated oil-in-water emulsion for at least one-half hour to obtain good resolution thereof.

Abstract: Method for the oxidation of values present in low valence stages in liquids nd of compounds which stabilize these low valence stages if they are present. Dinitrogen tetroxide (N.sub.2 O.sub.4) in liquid form is added to the value solution as an oxidation agent. The oxidation reactions which subsequently take place are conducted as substantially liquid-liquid reactions.

Abstract: A chemical process of isotopic enrichment of uranium makes use of isotopic exchange between an aqueous phase loaded with uranium III and another phase charged with uranium IV. Reduction and oxidation of uranium in aqueous phase are carried out using the same electrolyzer. Reduction may be by zinc amalgam which is later electrolytically reduced.

Abstract: A liquid-liquid extraction method and apparatus using an elongated extraction column arranged at an angle to the horizontal. The column is divided by means of partitions into a plurality of compartments which are in communication by apertures in such partitions. Each end of the extraction column has an inlet and an outlet, which can preferably be arranged concentrically, for the introduction and discharge of two immiscible liquids of differing densities, the less dense liquid being introduced into the lower inlet and discharged through the upper outlet and vice versa for the more dense liquid. The column during extraction is rotated either about its own axis or a spaced parallel axis. The extracting liquid can be circulated for back-extraction through a similarly arranged column containing a third liquid immiscible with the extraction liquid and of differing density.

Abstract: A process for producing reagents useful in organic synthesis, for removing metal values from solutions thereof, for the capture of aldehydes, of the general formula ##STR1## wherein Z designates a recurring part (CH.sub.2 --CH--CH.sub.2 -- of a polymeric backbone of a polymer like polystyrene, of a copolymer comprising polystyrene and divinylbenzene, and butadiene, or other copolymers comprising styrene moieties; or wherein Z is the aliphatic moiety of a long-chain aralkyl compound having a terminal aryl group; or wherein Z designates alkyl; corresponding compounds wherein instead of the optionally substituted phenyl group there is present an optionally substituted naphthyl group; wherein n is an integer of from 1 to 15, and wherein Q designates a group selected from: ##STR2## wherein R designates --H, lower alkyl, aryl, which may be substituted and wherein R" designates --H, alkyl, aryl, halogen, nitro or carboxy, or ##STR3## wherein R is --H, lower alkyl, aryl (which may be substituted), R.sub.

Abstract: The invention relates to the purification of homo- and copolymers of mono- and diolefines, as obtained from a solution polymerization in the presence of uranium catalysts, from the catalyst residues, and particularly to a process for the removal of the uranium from the hydrocarbon solution of the polymer, which solution is mixed with an aqueous solution of ammonium carbonate, the thus resulting aqueous phase being then separately treated for the recovery of the ammonium carbonate and of the uranium.

Abstract: In this process metal ions such as Ag.sup.+, Pb.sup.2+, Co.sup.2+, Cu.sup. 2+, Fe.sup.3+, etc., are extracted through a porous membrane impregnated with the first extractant containing chelating agents. The membrane contacts with an extraction feed on one side, and with the second extractant on the other side, and the objective metal ions are transferred from the feed to the second extractant. Throughout the extraction process, the pH values of the extraction feed, the impregnated extractant solution, and the second extractant are kept in decreasing order.An apparatus used for the above objective is also provided by this invention.

Abstract: A method of preparation for non-polluting storage of liquids containing phosphoric acid ester and hydrocarbons used in the reprocessing of spent nuclear fissile and/or fertile materials. The hydrocarbons are recycled for the production of fresh phosphoric ester-hydrocarbon solutions and the residue is brought into a form which can be fixed.

Abstract: A process for chemical enrichment of uranium with respect to a lighter one of its isotopes. The process consists in contacting uranium of valence state III and uranium of valence state IV, or a compound of uranium of valence state III and a different compound of uranium of valence state III. One of the phases which are contacted or the only phase is liquid. The system should be substantially free of elements which would cause uranium III to oxidize to valence IV.

Abstract: A process for separately recovering uranium, plutonium and neptunium substantially free of fission products from irradiated nuclear fuel is presented in which the fuel is dissolved in a strong mineral acid forming an aqueous dissolved nuclear fuel solution and treated to separate the uranium, plutonium and neptunium therefrom substantially free of said fission products by the sequential steps of solvent extraction, ion exchange and fluorination. The process has an improvement comprising the addition of a sufficient quantity of an additive of a stable metallic complex to the aqueous dissolved nuclear fuel solution prior to solvent extraction. This achieves improved purity of the separated uranium, plutonium and neptunium.

Abstract: Uranium is separated from analytical Group II and Group III metal ions in an aqueous liquor containing uranyl ions. The liquor is extracted with a non-interfering, water-immiscible, organic solvent containing a reagent which will react with the uranyl ions to form a complex soluble in the solvent. If the liquor is acidic, the solvent is washed with water. Then to the solvent is added an aqueous solution containing about 0.5 to 1.0 mole per liter of (NH.sub.4).sub.2 CO.sub.3 or NH.sub.4 HCO.sub.3 ions and sufficient sulfide ions to precipitate the metal ions as sulfides. The solvent and the aqueous solution are separated and the sulfides filtered from the aqueous solution. The ammonium-uranyl-tricarbonate in the aqueous solution can then be precipitated by increasing the concentration of (NH.sub.4).sub.2 CO.sub.3 or NH.sub.4 HCO.sub.3 ions to about 1.5 to 2.5 moles per liter. The precipitate is filtered and calcined to obtain U.sub.3 O.sub.8 or UO.sub.2.

Abstract: The method of selective stripping from plutonium-loaded organic solvents which may also contain uranium consists in passing the organic solvent in countercurrent contact with an aqueous solution of a salt of hydroxylamine and formic acid, the concentration of formic acid in the reaction medium being within the range of 1M to 5M.The method finds an application in the stripping of plutonium from trilaurylamine diluted in an aromatic hydrocarbon such as tert-butyl benzene or in the separation of uranium and plutonium contained in tributylphosphate diluted in an aliphatic hydrocarbon such as dodecane.

Abstract: The method of selective stripping from plutonium-loaded organic solvents which may also contain uranium consists in bringing the initial organic solvent into countercurrent contact with a solution containing a reducing agent consisting of an aromatic organic compound selected from the group comprising the substituted hydrazines, the polyamines, the aminophenols, and an agent for the removal of the nitrites which are formed.One field in which the method finds an application is the extraction of uranium and plutonium from nitric acid solutions derived from the reprocessing of irradiated nuclear fuels.

Abstract: an improved method of purifying wet-process phosphoric acid by sedimentation, in which the crude acid is intimately mixed with an appropriate amount of finely divided silica or silicate. The result is that the absolute magnitude of the zeta potential of the suspended solids, particularly humus and gypsum, decreases to a value that allows them to aggregate, settle rapidly, and be removed by conventional methods. The Si:F ratio is increased, effecting a reduction of fluorine contamination. The rate of growth of gypsum crystals is increased, reducing the amount of post-precipitation of gypsum and other particulates. Because the rate of settlement is increased, the holding time prior to further processing, such as concentrating to merchant-grade acid, is decreased, reducing storage and space requirements and associated capital investment as well as investment in product inventory.