Abstract: A process for reducing the valence state of ferrous and other ions present in phosphoric acid by heating the acid in the presence of a pressurized reducing gas, preferably hydrogen. The pressurized gas reduces the ions without an addition of metallic iron or other impurity. This process is desirably used with processes for recovering uranium from wet process phosphoric acid, wherein ferric or uranyl ions in the phosphoric acid are reduced in a pressurized reducing gas.

Abstract: A process for separately recovering uranium and hydrofluoric acid from a waste liquor containing uranium and fluorine comprises a neutralizing precipitation step wherein a magnesium compound is added to the waste liquor containing uranium and fluorine to form a precipitate and the thus formed precipitate is then separated; a distillation step wherein an aqueous solution of sulfuric acid is added to the precipitate separated in said neutralizing precipitation step to dissolve the precipitate and the thus formed solution is then distilled to recover hydrofluoric acid as a distillate; and a uranium recovery step wherein uranium is recovered from a residue produced by said distillation step.

Abstract: A process for the selective concentration of metal values in solution wherein said metal-containing solution is contacted with a multiple-phase system having a common solvent, thereby causing the preferential migration of metal values into one phase of said multiple-phase system. The phases of the system may then be isolated and the metal values recovered therefrom by conventional techniques.

Abstract: Process for preventing the extraction of technetium and/or rhenium, particularly during the extraction of uranium and/or plutonium by an organic solvent.This process permitting the extraction of a chemical element, such as uranium or plutonium present in an aqueous solution containing both said element, technetium and/or rhenium and zirconium and/or hafnium consists of contacting the aqueous solution with an organic solvent able to extract said element, wherein for preventing the extraction of the technetium and/or rhenium with said element, to the aqueous solution is added a zirconium and/or hafnium complexing agent in a quantity adequate for complexing all the zirconium and/or hafnium, said agent being soluble in the aqueous solution.

Abstract: A process for the recovery of an organic phase and an aqueous phase from three phase emulsions such as those formed during the extraction of uranium from wet phosphoric acid is described. Such emulsions contain a light-density liquid phase and a heavy-density liquid phase and are stabilized by a solid phase of intermediate density. The emulsion is first heated and then separated into its three components using a centrifugal filter with an appropriate filter aid. At high filter feed rates the dense liquid phase passes freely through the filter media while the light phase liquid begins to accumulate in the centrifuge and is withdrawn from the centrifuge via a properly positioned skimmer tube. The apparatus containing the skimmer tube is also described.

Abstract: A process for the separation of substances hindering the recovery of the fissionable materials uranium and plutonium and for the separation of the fissionable materials to be recovered in a reprocessing process for spent, irradiated nuclear fuel- and/or fertile materials. A second and a third wash of the organic phase is performed for residual ruthenium separation and residual zirconium separation, and there is a repetition of the Pu stripping step with simultaneous electrolytic reduction of Pu(IV) to Pu(III). The second and third wash solutions or the aqueous phase employed for the repetition of plutonium stripping, respectively, each contains a high concentration of product uranyl nitrate. The aqueous run-off from the second and third washes and from the repetition of the Pu stripping step is indirectly fed back into the aqueous fuel solution employed in the first extraction step of the reprocessing method by first feeding these run-offs to an intermediate treatment.

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 process for reductive plutonium stripping from an organic reprocessing solution into an aqueous, nitric solution by use of an electrolytic current, in which the aqueous solution is free of agents for the stabilization of the reduced valence of the plutonium, a HNO.sub.3 concentration in the range of 0.05 to 1.0 mol/l is established in the aqueous solution, and the reduction of Pu(IV) to Pu(III) is carried out at a maximum temperature of 40.degree. C.

Abstract: Process for the removal of plutonium polymer and ionic actinides from aqueous solutions by absorption onto a solid extractant loaded on a solid inert support such as polystyrenedivinylbenzene. The absorbed actinides can then be recovered by incineration, by stripping with organic solvents, or by acid digestion. Preferred solid extractants are trioctylphosphine oxide and octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide and the like.

Abstract: A process for the separation of neptunium from an organic phase, which is developed in the recovery of irradiated nuclear fuel and/or fertile material. The organic phase contains uranium-, plutonium- and neptunium ions, tritium in the form of tritiated water and fission products in ionic form, as well as an organic extraction agent dissolved in diluent. After a first wash step, and before the organic phase is further fed to a uranium-plutonium separation or to a uranium-plutonium coreextraction, the organic phase is brought into contact with an aqueous solution containing diluted HNO.sub.3, butyraldehyde and a low concentration of sulfamic acid in countercurrent flow as a second wash step for the selective reduction of Np (VI) to Np (V) and for selective stripping of Np (V), with respect to U and Pu, from the organic into an aqueous phase.

Abstract: The invention concerns the recovery of heavy metals from concentrated solutions.The process comprises complexing the metals with an organophosphorous complexing agent and recovering the metallic complex by sedimentation, filtration, flotation and the like.The process can be used to recover uranium and rare earths from phosphoric acid solutions.

Abstract: Ferric nitrate leaching at 75.degree. C. is found to remove up to 97% of the uranium and 93% of the radium from ores occurring in the Elliot Lake area of Canada, after an initial flotation-separation of the sulfide minerals from the ore. In processes of the invention an aqueous acidic ferric nitrate solution of relatively low concentration, e.g. 0.01M to 0.1M is used, giving tailings which are effectively sulfide-free (less than 0.45 wt %) and with radium levels approaching a desired maximum value of 24 pCi/g. Radium may be removed from the leachate by adsorption and uranium by solvent extraction. 80-87% of the ferric nitrate may be recirculated for further leaching. Because of the low reagent concentrations and the recycle of the ferric nitrate, it is possible to keep nitrate ion levels in the effluent below the prescribed level of 10 ppm.

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: An apparatus is provided that is useful for effecting liquid-liquid extraction by contacting a first liquid medium with a substantially immiscible heavier second liquid medium. Each mixer-settler unit includes a vertically extending settling tank having a top and a bottom with an outlet for the first liquid medium near the top and an outlet for the second liquid medium near the bottom. An elongated extraction column extends generally vertically upwardly through the settling tank bottom. The extraction column is open at its top with the top of the extraction column below the top of the settling tank. A diverter surrounds and extends downwardly along a top portion of the extraction column. The diverter has a closed top and an open bottom with an annulus being between the diverter and the portion the extraction column surrounded by the diverter. The dispersion flows from the pumping and mixing means upwardly through the extraction column and out its top.

Abstract: Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Abstract: Liquid-liquid extraction of a substance from an aqueous solution thereof, which consists in preparing a microemulsion of this solution with a hydrophobic liquid in such a way that the layer of microemulsion is accompanied by a layer of consumed aqueous solution and a layer of hydrophobic liquid containing the substance to be extracted.

Abstract: The invention provides an extractant composition comprising as an extraction agent the reaction product of jojoba oil and dialkyl or diaryl phosphite. The invention also provides a method for extracting actinide metal ions from an aqueous solution containing the same comprising contacting the solution with an extractant organic solution containing the above extraction agent and separating the resulting phases.

Abstract: A method of continuous ion exchange for waste water treatment and metal recovery employs two membranes, each disposed in its own fluid-tight chamber. A feed solution containing metal ions is passed in contact with one membrane, the opposite side of which is in contact with a recirculating flow of liquid ion exchange material which receives selected dissolved mineral ions. The liquid ion exchange material is then passed over a second membrane, the other side of which is supplied with an eluant solution for further selective recovery of the desired mineral ion or ions. During recirculation the liquid ion exchange material is preferably passed through an aqueous separator. An apparatus for the practice of the present invention is also disclosed.

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: 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 method for oxidation of reduced cations and humate constituents of filtered, wet process phosphoric acid comprising the step of treating the acid with an oxygen source in the presence of activated carbon.

Abstract: The invention relates to new industrial products of the general formula ##STR1## a process for the manufacture of these products and their application as extraction agents in hydrometallurgy.

Abstract: A process for the separation of the actinides and lanthanides present in the trivalent state in an acid aqueous solution, wherein the actinides present in such aqueous solution are extracted selectively in an organic solvent by bringing the solution into contact with an organic solvent comprising a first extracting agent formed by an organic bonding agent having an electron-donor nitrogen atom and a second extracting agent formed by an acid organosoluble organic compound able to exchange its H.sup.+ ions for metal ions or by metallic salt of such compound.Application to the nuclear industry, inter alia in the field of the treatment of aqueous effluents containing lanthanides and actinides, such an transuranic elements.

Abstract: A process is described for the recovery of tetravalent uranium from wet-process phosphoric acid utilizing an alkyl pyrophosphoric acid extractant or the like. After extracting the tetravalent uranium from wet-process acid, iron is stripped from the pregnant extractant into an oxalic acid stripping solution and then the tetravalent uranium is stripped from the pregnant extractant into an oxalate stripping solution. The oxalate stripping solution is an aqueous solution of an alkali metal or ammonium oxalate. The barren extractant is recycled for contacting with fresh wet-process acid. The uranium is oxidized and then precipitated in the oxalate stripping solution. The precipitated solids are separated from the solution, and the uranium is dried to a UO.sub.3 product.

Abstract: A method for separating an ionic substance from a liquid medium, which comprises including a metal ion, a metal oxide ion, a metal complex ion, ammonium compounds, etc. dissolved or dispersed in the liquid medium by using a fluorine containing compound of the following formula[{Rf-(A).sub.a -Y}(X).sub.b ].sub.n (Z).sub.ccontaining a fluoroalkyl group (Rf) having 3 to 20 carbon atoms and a group (Y) having affinity for the ionic substances. A composition for trapping ionic substances, comprising the aforesaid fluorine-containing compound as a main ingredient. The invention can be advantageously applied to the recovery of useful metals from ocean waters.

Abstract: A recovery process of uranium comprising:(1) extracting uranium ions with an organic solvent containing one or more compounds selected from the group consisting of alkyl phosphoric acid, alkyl-aryl phosphoric acid, alkyl dithio phosphoric acid, aryl dithio phosphoric acid, neutral phosphoric acid ester and alkyl amine together with a petroleum hydrocarbon as a diluent; and(2) stripping the uranium ions in the resultant organic solvent from the step (1) to an aqueous phase with contact of an aqueous solution containing one or more compounds selected from the groups of NH.sub.4 F, NH.sub.4 HF.sub.2, KF or KHF.sub.2.

Abstract: A two stage reductive stripping process for recovering uranium from wet process phosphoric acid, wherein the ferrous ions required for the first-stage reductive strip are supplied by heating a portion of acid raffinate phosphoric acid from the first-stage extraction in the presence of pressurized hydrogen gas. The pressurized hydrogen gas reduces the ferric ions in the raffinate to the ferrous state without any addition of metallic iron or other impurity, so that the uranium-enhanced reductive strip solution supplied to the second stage from the first stage reductive strip has a low concentration of iron impurity, and no further purification to remove iron impurity is required.

Abstract: Use of succinosuccinic acid diesters of the formula ##STR1## in which R is an alkyl, alkenyl or cycloalkyl having 4 to 24 C atoms, either dissolved in a water-immiscible organic solvent, or at elevated temperature in the form of their melts, as cation-selective liquid membranes.

Abstract: A method for the separation of actinides from lanthanides present in a trivalent state in an acidic aqueous solution.Said method consists in selectively extracting in an organic solvent the actinides present in said solution, by bringing said aqueous solution into contact with an organic solvent comprising a system of extractants constituted by an acidic organo-phosphorated compound containing at least one electron doner sulfur atom such as di-2-ethylhexyl-dithio-phosphoric acid, and by a neutral organophosphorated compound containing at least one electron-doner oxygen atom such as tributyl phosphate.

Abstract: The present invention relates to a process for recovering uranium from raffinate which is obtained by extracting phosphoric acid from a uranium-containing wet-process phosphoric acid with the aid of organic extractants and separating the resulting organic phosphoric acid extract from residue not taken up by the extract. To this end, the raffinate residue is subjected to thermal treatment and thereby freed from dissolved or emulsified residual extractant. Next, the raffinate is treated with a water-immiscible solvent to extract the uranium, and the extracted uranium is separated from the undissolved raffinate portion.

Abstract: Ferric chloride leaching at temperatures in the range 47.degree.-74.degree. C. is found to remove up to 97% of the uranium from ores occurring in the Elliot Lake area of Canada, but radium removal was found to be poor due to the formation of sulphates from the sulphides present in the ore. In processes of the invention the sulphides are initially removed by flotation, when aqueous acidic ferric chloride of relatively low concentration, e.g. 0.1 M can extract as much as 92% of the radium, giving tailings which are effectively sulphide-free and with radium levels approaching a desired maximum of 24 pCi/g. Radium may be removed by adsorption on manganese dioxide and uranium may be removed by liquid extraction with D2EHPA (DAPEX process). The ferric chloride may be recirculated for further leaching, with reduction before the uranium extraction and reoxidation afterwards. Because of the recycle, it is possible to keep chloride ion levels in the effluent below the prescribed level in Ontario, Canada of 750 ppm.

Abstract: A process is described for the removal of uranium values from contaminated wet-process phosphoric acid solutions using an addition thereto of first an aliphatic ketone and then an inorganic fluoride, whereby high efficiencies in the removal of uranium as a solid, filterable precipitate are achieved.

Abstract: Increasing the strip coefficient of a strip solution stream in a reductive stripping uranium recovery process involving wet process phosphoric acid feed is accomplished by adding effective amounts of H.sub.2 SO.sub.4 to the strip solution stream before it exits the reductive stripping means.

Abstract: An improved method and apparatus for producing a dispersion of substantially immiscible liquids which employs a conduit having an upstream section divided into first and second channels of variable length and a downstream section for mixing the liquids. The apparatus also includes means for varying the length of the first and second channels and means for flowing the liquids separately through the channels whereby the liquids mix in the downstream section of the conduit to form the dispersion. In accordance with one embodiment, a conventional mixer-settler is modified to include the conduit mounted at an upstream end of the settling chamber so that its inlet is adjacent the mixing chamber and its outlet is approximately at the same height as the organic-aqueous interface in the settling chamber.

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: In a uranium recovery process, barren, organic solvent, which contains entrained, reduced iron containing phosphoric acid, exiting the stripper is contacted with oxidized raffinate acid, before extraction, in an amount effective to remove about 70% to 98% of the entrained acid.

Abstract: An improvement in effecting uranium recovery from phosphoric acid solutions is provided by sparging dissolved oxygen contained in solutions and solvents used in a reductive stripping stage with an effective volume of a nonoxidizing gas before the introduction of the solutions and solvents into the stage. Effective volumes of nonoxidizing gases, selected from the group consisting of argon, carbon dioxide, carbon monoxide, helium, hydrogen, nitrogen, sulfur dioxide, and mixtures thereof, displace oxygen from the solutions and solvents thereby reduce deleterious effects of oxygen such as excessive consumption of elemental or ferrous and accumulation of complex iron phosphates or cruds.

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: Uranium values are recovered from a wet-process phosphoric acid solution by extracting said solution with a first organic extractant, reductively stripping the resulting first organic phase of its uranium values with a strip solution including and in which ferrous ion is utilized to reduce uranyl ions in said first organic phase to uranous ions therein, disengaging the strip solution from said first organic extractant and oxidizing same to convert the uranous ions therein to uranyl ions, next extracting said oxidized strip solution and the uranium values contained therein with a second organic extractant, and then stripping said uranium values from the resulting second organic phase, said recovery featuring (i) washing with an iron-free aqueous wash solution, and upstream of the reductive stripping thereof, the organic phase resulting from said first extraction, and (ii) utilizing effluent, iron-free wash solution from the step (i) to wash the organic phase resulting from said second extraction and concomitan

Abstract: Process for the plutonium decontamination of an organic solvent comprising adding to the said organic solvent a reducing agent which is a dialkyl dithiophosphoric acid and which is soluble in the organic solvent, bringing the organic solvent containing the reducing agent into contact with an acid aqueous solution and separating the aqueous solution containing the plutonium from the decontaminated organic solvent, useful in reprocessing of irradiated nuclear fuels.

Abstract: An acidic solution containing metal values and also containing humic acid impurities, is purified by: (1) forming a gas in the acid solution, (2) adding high molecular weight anionic organic flocculant in a volume ratio of gas containing acid solution: flocculant of 1,000:0.002 to 0.10, to form a bottom, purified, aqueous acidic phase containing metal values and a top flocculated humic acid impurities froth phase and (3) removing the humic acid froth phase.

Abstract: A process for solubilizing uranium and other values in an ore containing the same together with aluminum and phosphorus and effecting regeneration of a mineral acid employed to solubilize the ore. The regeneration is effected by heating the spent acid solution resulting from solubilization of the ore in a reaction zone to a temperature above 100.degree. C. while maintaining at least the autogenic pressure of the heated solution within the reaction zone. The treatment causes aluminum phosphate to precipitate from the solution while simultaneously causing regeneration of at least a portion of the mineral acid in the solution that was consumed to originally solubilize the ore. The dissolved uranium and other elements of value can be recovered from the solution, either before or after acid regeneration, by any known technique. The regenerated mineral acid then can be used to solubilize fresh ore.

Abstract: Use of succinosuccinic acid diesters of the formula ##STR1## in which R is an alkyl, alkenyl or cycloalkyl having 4 to 24 C atoms, either dissolved in a water-immiscible organic solvent, or at elevated temperature in the form of their melts, as cation-selective liquid membranes.

Abstract: A process to maintain a high iron +2/iron +3 concentration in the reductive stripping system for recovering uranium from wet-process phosphoric acid, comprises contacting partially oxidized strip acid, containing substantial amounts of iron +3, which had just previously stripped uranium values from an organic solvent, with elemental iron to reduce iron +3 to iron +2 and provide a Fe.sup.+2 /Fe.sup.o conversion ratio of from about 1.5 to 3.0.

Abstract: Iron contained in phosphoric acid solution is reduced from the trivalent to the bivalent oxidation stage. To this end, red phosphorus is used as the reductant and the reduction is effected in the presence of copper.

Abstract: Process for recovering yttrium and lanthanides from wet-process phosphoric acid by adding a flocculant to the phosphoric acid, separating out the resultant precipitate and then recovering yttrium and lanthanides from the precipitate. Uranium is recovered from the remaining phosphoric acid.

Abstract: Uranium in wet-process phosphoric acid in the tetravalent state is extracted with an alkylphenyl acid phosphate extractant comprising a mixture of mono- and di(alkylphenyl) esters of orthophosphoric acid. The pregnant extractant is stripped with a suitable stripping solution, and the barren extractant recycled to the extractant step. At least a portion of the recycled extractant is treated with concentrated sulphuric acid to remove organic and inorganic impurities including alkylphenol present in the barren extractant as a result of hydrolysis from the mixture of mono- and di-(alkylphenyl) esters of orthophosphoric acid to regenerate the extractant.

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.

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: A reductive stripping flow sheet for recovery of uranium from wet-process phosphoric acid is described. Uranium is stripped from a uranium-loaded organic phase by a redox reaction converting the uranyl to uranous ion. The uranous ion is reoxidized to the uranyl oxidation state to form an aqueous feed solution highly concentrated in uranium. Processing of this feed through a second solvent extraction cycle requires far less stripping reagent as compared to a flow sheet which does not include the reductive stripping reaction.