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 the recovery of the uranium present in phosphoric acid produced by a wet process in (A) by means of a suitable solvent (L.sub.9), which is carried out after separation of the gypsum in (B) formed in the attack operation, and elimination of the solid materials which are still in suspension, characterized in that, in order to avoid the formation of dross in the course of the operation of extracting the uranium which is previously reduced in (D), the step of eliminating the solid materials which are still in suspension is effected by a final solid-liquid separation operation in (C) and/or in (E), prior to extraction of the uranium in (F), in the presence of an added fraction of gypsum (S.sub.22) and/or (S.sub.23) resulting from the production of H.sub.3 PO.sub.4.

Abstract: The present invention relates to a proces for separating rare earths and uranium from a UF.sub.4 concentrate and for placing them into useful form, comprising attacking the UF.sub.4 concentrate with potassium hydroxide, followed by nitric acid dissolution of the resulting precipitate, and extraction of the solution using an organic solvent. The extraction results in an organic solution containing purified uranyl nitrate, and an aqueous solution from which rare earths are precipitated by means of a base.

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: 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: The present invention relates to a process for the recovery of uranium and other minerals from uranium ore where at least part of the uranium is present as refractory uranium-mineral complexes, comprising subjecting the uranium ore to mild oxidative carbonate leach fluid to dissolve and remove readily soluble uranium minerals, subsequently subjecting the uranium ore to an oxidative chemically severe leaching system to dissolve and remove the refractory uranium-mineral complexes, and separating and recovering the uranium and other mineral species in the leachate fluids. The process may be applied to in-situ uranium leaching operations or to surface leaching operations.

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: 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: In a preferred embodiment, a process for extracting uranium from wet-process phosphoric acid (WPA), comprises separating uranium from WPA to produce a loaded uranium solution stream and a uranium depleted WPA stream. The loaded uranium solution stream is then contacted by with an ion exchange resin. Uranium species bound to the ion exchange resin are eluted by contacting the resin with a solution comprising anions to produce a loaded uranium eluant stream. The loaded uranium eluant stream is treated to provide a uranium containing product.

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 process for extracting the uranium contained in phosphoric acid solutions by means of an extracting agent comprising an alkylpyrophosphoric acid, which comprises bringing into contact, in an agitated condition, the inorganic, phosphoric acid phase and an organic phase containing the extracting agent, thereby producing an emulsion, which is characterized in that, in an extraction unit comprising n stages in a cascade configuration, for each extraction stage, the emulsion is produced in a first step by simultaneously subjecting the two phases for a period of time T.sub.1 to an intense mechanical shearing action corresponding to a shearing coefficient of at least 5000 seconds.sup.-1 in order to multiply the contact surfaces for contact between said two phases, and then said emulsion in a second step is abruptly broke in a time T.sub.2, the sum of the times required for carrying out the two steps being at most 20 minutes.

Abstract: A chemical element to be very efficiently separated from uranium starting from an acid aqueous phase, in an extraction cycle for the uranium, when this chemical element is present in said phase at a concentration less than that of the uranium, or even as a trace element, and when it is moreover less extractable by the extractant used in this extraction cycle than is the uranium. The chemical element can notably be neptunium(IV) or thorium 228.

Abstract: A process for recovering uranium from components contaminated with uranium oxide includes providing a cleaning apparatus with a cleaning solution for dissolving the uranium oxide of the components, carrying out a cleaning process by introducing a batch of components into the cleaning apparatus, and carrying out a measurement for determining the uranium content of the components. The cleaning and the measuring are repeated if a limit value for the uranium content is exceeded. The components are discharged from the process if the uranium content falls below a limit value. The cleaning is carried out on a plurality of successive batches of components until a control measurement indicates an unsatisfactory cleaning action of the cleaning solution. The uranium oxide dissolved in the cleaning solution is recovered after indication of the unsatisfactory cleaning action.

Abstract: A chemical element to be very efficiently separated from uranium starting from an acid aqueous phase, in an extraction cycle for the uranium, when this chemical element is present in said phase at a concentration less than that of the uranium, or even as a trace element, and when it is moreover less extractable by the extractant used in this extraction cycle than is the uranium. The chemical element can notably be neptunium(IV) or thorium 228.

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: A method of recovering uranium from phosphoric acid solutions containing same comprises extracting the uranium from the phosphoric acid with an organic solution of an alkylphenyl pyrophosphate.

Abstract: The invention relates to a process for reprocessing a spent nuclear fuel and for preparing a mixed uranium-plutonium oxide, which process comprises: a) the separation of the uranium and plutonium from the fission products, the americium and the curium that are present in an aqueous nitric solution resulting from the dissolution of the fuel in nitric acid, this step including at least one operation of coextracting the uranium and plutonium from said solution by a solvent phase; b) the partition of the coextracted uranium and plutonium to a first aqueous phase containing plutonium and uranium, and a second aqueous phase containing uranium but no plutonium; c) the purification of the plutonium and uranium that are present in the first aqueous phase; and d) a step of coconverting the plutonium and uranium to a mixed uranium/plutonium oxide. Applications: reprocessing of nuclear fuels based on uranium oxide or on mixed uranium-plutonium oxide.

Abstract: A process for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone.

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: Uranium is extracted from wet process phosphoric acid by extraction with a mixture of a diorganophosphate and a neutral phosphorus compound, which is preferably a triorgano phosphine oxide, in the presence of nitrate to form an organic extract layer containing uranium and an aqueous acid layer, which are separated.