Abstract: The purpose of the process is to remove and to recover metals from their aqueous solution by the extraction process. As extractant is used monoesters of phosphonic acid wherein the alkyl group is a phenyl-vinyl group or straight-chained and the ester group is straight-chained. The particular advantage of the process is that the metals can be removed from aqueous solutions to be treated without neutralization of the acid quantity produced during extraction, and this acid solution produced can be circulated e.g. to the stage before the extraction. The process can be used to the removing of metals from the industrial waste waters.

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: This invention relates to a process for the recovery of uranium from wet process phosphoric acid. More particularly, it concerns the use of a combination of a dialkyl phosphoric acid and a mixture of trialkyl phosphine oxides to extract uranium from wet process phosphoric acid.

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 recovery of uranium which has been extracted from phosphate-bearing solutions by means of an organic solvent and which is re-extracted from said solvent by means of hydrofluoric acid is disclosed.The process is characterized in that sodium ions are introduced into the solution of hydrofluoric acid, while aluminum and magnesium ions may also be added to the sodium ions. That solution may be produced by recycling of a fraction of the suspension of fluoride from the re-extraction step, after having separated the solvent, and to which a make-up of sodium, aluminum and magnesium ions and hydrofluoric acid was added.

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: Uranium is recovered as UF.sub.4 from phosphate solutions. The uranium is reduced to the tetravalent state and extracted with an organic extractant. The uranium is recovered as UF.sub.4 by reextracting with an aqueous HF solution which includes UF.sub.4 in suspension for improved reextraction.

Abstract: Paramagnetic metals are separated from aqueous media containing them in low concentration by first fixing the metals on bacterial yeast or other cells so as to render the cells magnetic, and then recovering the cells by a high gradient magnetic separation technique. The metal and the cells are contacted in the presence of a compound which is converted by the cells into a product which interacts with the metal and causes it to become bound to the cells. The process is particularly useful for removing low concentrations of highly toxic metals, e.g. uranium, from industrial effluents containing them.

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: In the process for treating irradiated nuclear fuel to effect separation of uranium plutonium other higher actinides, and fission products, in which nitric acid treatment, followed by solvent extraction, then backwashing the reduction of tetra- and hexa-valent plutonium to the tri-valent form, then a second solvent extraction by which the tri-valent plutonium remains in the aqueous phase while uranium goes into the solvent phase, the reduction step is performed by hydrazine with or without tetra-valent uranium nitrate and catalyzed by technetium in the tetra-valent form with or without technetium in one or more higher valency states. The technetium can be present in the system as an irradiation product or be added to the process stream in a combined form.

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: A process is described for the recovery or uranium from wet-process phosphoric acid utilizing an alkyl pyrophosphoric extractant. The extractant also contains a modifier for retaining the alkyl pyrophosphoric acid ester in solution in an essentially water-immiscible organic diluent during stripping. After extracting the uranium from wet-process acid, the APPA extractant is treated with an oxidizing agent such as hydrogen peroxide and the uranium stripped into an alkaline stripping solution. The alkaline stripping solution is an aqueous solution of an alkali metal or ammonium carbonate unsaturated in uranium. The barren extractant is recycled for contacting with fresh wet-process acid. Any ferric iron present is precipitated in the stripping solution and then separated from the solution. The uranium is precipitated, separated, dried and calcined to a U.sub.3 O.sub.8 product.

Abstract: A process is described for the recovery of uranium from wet-process phosphoric acid utilizing an alkyl pyrophosphoric extractant. The extractant also contains a modifier for retaining the alkyl pyrophosphoric acid in solution in an essentially water-immiscible organic diluent during stripping. After extracting the uranium from wet-process acid, the APPA extractant is treated with an oxidizing agent such as hydrogen peroxide and the uranium stripped into an alkaline stripping solution. The alkaline stripping solution is an aqueous solution of an alkali metal or ammonium carbonate or hydroxide. The barren extractant is recycled for contacting with fresh wet-process acid. The uranium and any ferric iron present is precipitated in the stripping solution. The uranium is dissolved in an aqueous solution such as an aqueous solution of ammonium uranyl tricarbonate (AUT), any precipitated ferric solids are separated from the solution, and the uranium is reprecipitated, separated, dried and calcined to a U.sub.3 O.sub.

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: The uranium, yttrium, thorium and rare earth values contained in a phosphate rock are essentially totally recovered therefrom by, during the wet-process preparation of phosphoric acid from said phosphate rock, acidulating same in the presence of aluminum and/or iron, and optionally silica, and thence recovering said values from the phosphoric acid thus produced.

Abstract: A process for the removal of cadmium contained in wet-process phosphoric acid by flotation by means of a cadmium-collector anionic surface active agent and an injected gas in the presence of other impurities including iron and possibly uranium which is characterized in that, in order to improve the removal of cadmium, the iron contained in the phosphoric acid in the trivalent state is reduced to the divalent state before the cadmium collector is introduced into the medium to be purified by flotation.The collector agent is selected from the group of dithiophosphoric acid esters and the alkali metal salts thereof.

Abstract: New diphosphonic acid diesters in which the two phosphorus atoms are bound by a hydrocarbon group while each of the two acid functions of the diphosphonate is esterified by a radical having at least three carbon atoms are prepared by the treatment with a weak base of a corresponding tetramethyl diphosphonate, thereupon replacement of the cations of the base in the resultant disalt, by a radical R by means of a halide of said radical, and finally hydrolysis of the mixed diphosphonate thus obtained. The new compounds are suitable for various known uses of the different diphosphonates and in particular for the complexing of heavy metals; they are used in particular for the extraction of uranium and metals associated with it.

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: 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 process for making into useful products the uranium and rare earths contained in impure uranium tetrafluoride resulting from the recovery of uranium from phosphoric acid, comprising dissolving it in a hot condition in a nitric medium in the presence of an aluminum compound, treating the resulting solution with a solvent for extracting uranyl nitrate, which contains a phosphoric ester, and separating from the aqueous phase from which the uranium is removed, the solvent which is charged with uranyl nitrate to be made into a useful product, which provides that, in order to achieve easy separation of the aqueous phase from which the uranium has been removed, from the uranyl nitrate extraction solvent:(a) The operation of dissolution of UF.sub.

Abstract: Hydroxymethane diphosphonic acid and alkali metal or ammonium salt of such acid are prepared. They are useful in detergent compositions and in sequestering and chelating polyvalent metals.

Abstract: A process for stripping hexavalent uranium from an organic solution using phosphoric acid containing ferrous ion wherein the ferrous ion is provided by electrolytic reduction of ferric ion with minimal production of hydrogen.

Abstract: A process for the recovery of actinide and lanthanide values from aqueous solutions with an extraction solution containing an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms and phase modifiers in a water-immiscible hydrocarbon diluent. The addition of the extractant to the Purex process extractant, tri-n-butylphosphate in normal paraffin hydrocarbon diluent, will permit the extraction of multivalent lanthanide and actinide values from 0.1 to 12.0 molar acid solutions.

Abstract: A process for the recovery of actinide and lanthanide values from aqueous acidic solutions with an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high level nuclear reprocessing waste solutions.

Abstract: An otherwise unusable western sandstone uranium ore is blended with uranium-containing phosphate rock. The mixture is then digested with sulfuric acid to produce a wet process phosphoric acid solution containing higher levels of uranium. Recovery of the uranium values from this solution can be effected by various known processes such as solvent extraction.

Abstract: A synergistic extractant combination consisting of di(2-ethylhexyl) phosphoric acid (D2EHPA) and dibutyl butyl phosphonate (DBBP) in kerosene is employed in a two-cycle separation process for the recovery of uranium from wet-process phosphoric acid. The addition of the sulfuric acid and water scrubbing steps for the recycled extractant provides no disadvantages with respect to the comtamination and dilution by the ammonium ion and water to the phosphoric acid and also no precipitation occurs in the second cycle extraction step. The advantages of this process are lower chemical cost, higher product purity and better phase separation in comparison with the previous process.

Abstract: A method for decontaminating uranium product from the Purex process comprises addition of hydrazine to the product uranyl nitrate stream from the Purex process, which contains hexavalent (UO.sub.2.sup.2+) uranium and heptavalent technetium (TcO.sub.4 -). Technetium in the product stream is reduced and then complexed by the addition of oxalic acid (H.sub.2 C.sub.2 O.sub.4), and the Tc-oxalate complex is readily separated from the uranium by solvent extraction with 30 vol. % tributyl phosphate in n-dodecane.

Abstract: Vanadium is recovered from acidic solutions by oxidizing the vanadium with Caro's acid to the pentavalent state and obtaining the oxidized vanadium by solvent extraction.

Abstract: A process for the selective recovery of cadmium, molybdenum, zinc, nickel and other metal values from wet process phosphoric acid and other acidic to slightly basic carrier solutions, wherein the metal-bearing solution is contacted with an organophosphene extractant to precipitate the metal values for subsequent separation from the solution. Separation may be effected by mechanical means or by scrubbing with a water-immiscible organic solvent such as kerosene for subsequent recovery of the metal values. The metal specie recovered is determined by the concentration of the organophosphene, which may be selectively adjusted to recover a series of metal values in a sequence of stages.

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: In the reductive stripping of uranium from an organic extractant in a uranium recovery process, the use of phosphoric acid having a molarity in the range of 8 to 10 increases the efficiency of the reductive stripping and allows the strip step to operate with lower aqueous to organic recycle ratios and shorter retention time in the mixer stages. Under these operating conditions, less solvent is required in the process, and smaller, less expensive process equipment can be utilized. The high strength H.sub.3 PO.sub.4 is available from the evaporator stage of the process.

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 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: Uranium is recovered from a carbonate leach solution containing a dissolved uranium salt and a monovalent ion. The pH of the leach solution is adjusted to about 5 to about 7.5, and preferably to about 6 to about 7. Phosphate ion is then added to typical in-situ leach solutions in an amount from about 10 to about 30 mole % in excess of the amount needed to stoichiometrically react with the uranium in said solution. This results in the precipitation of a compound made up of the monovalent ion, uranium, and the phosphate ion, which is insoluble in the solution. The precipitate is then separated from the solution preferably by means of a centrifuge or a vortex clarifier. It can then be dissolved in acid, and the uranium extracted into an organic solvent such as DEHPA-TOPA in kerosene.

Abstract: Aqueous ammonium uranyl tricarbonate strip solution is purified by using activated carbon to remove ammonium di(2-ethylhexyl)phosphate impurity.

Abstract: Triphosphonic esters, each of the three phosphorus atoms of which is bound to a carbon atom of the same hydrocarbon group, having 2 or 4 free acid functions or two salt functions, may be used for various known uses of phosphonates, including the extraction of heavy metals.

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: 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: Rare earth, uranium and thorium values are separated and recovered from aqueous solutions of the chlorides thereof, said aqueous solutions having an acidity of less than 2 N and a concentration in such values, expressed as the oxides thereof, of at least 50 g/l, by liquid-liquid extracting said aqueous solutions with an organic extractant comprising at least one neutral organophosphorus compound.

Abstract: New diphosphonic acid diesters in which the two phosphorus atoms are bound by a hydrocarbon group while each of the two acid functions of the diphosphonate is esterified by a radical having at least three carbon atoms are suitable for various known uses of the different diphosphonates and in particular for the complexing of heavy metals; they are used in particular for the extraction of uranium and metals associated with it.

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 for treating a hydrometallurgical suspension resulting from the acid attack on an ore containing at least one metal element to be put to use, and non-attackable mineral materials, a fraction of which is formed of clays, comprising extracting the useful metal element which has gone into solution in the attack operation, by means of an organic solvent belonging to the group of alkyl phosphates, which is characterized by introducing a condensed mineral phosphate into the ore attack medium, for the purpose of limiting the losses due to adsorption of the organic extraction solvent by the clays.The process applies more particularly to uraniferous, molybdeniferous, vanadiferous and cobaltiferous ores.

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: 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.