Abstract: Uranium and technetium in the product stream of the Purex process for recovery of uranium in spent nuclear fuel are separated by (1) contacting the aqueous Purex product stream with hydrazine to reduce Tc.sup.+7 therein to a reduced species, and (2) contacting said aqueous stream with an organic phase containing tributyl phosphate and an organic diluent to extract uranium from said aqueous stream into said organic phase.

Abstract: Method for separating plutonium ions from an aqueous solution containing sulfuric acid. The method comprises introducing into the aqueous solution 0.1 to 1.5 moles of nitrate ions per liter of aqueous solution. To the aqueous solution containing nitrate ions, there is added an organic phase comprising a solution of 0.1 to 1.0 M di-2-ethylhexylphosphoric acid in kerosene in a volume ratio of the aqueous solution containing nitrate ions to the organic phase of between 1:1 and 4:1 to extract the plutonium ions into the organic phase. The organic phase containing plutonium ions is then separated from the aqueous solution. A re-extractant aqueous solution containing 0.2 to 1.0 M oxalic acid, and 0 to 0.5 M nitric acid is then added to the separated organic phase to re-extract the plutonium ions into the re-extractant aqueous solution. The re-extractant aqueous solution containing plutonium ions is then separated from the organic phase.

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: Process for the recovery of uranium (VI) present in a phosphoric acid solution by contacting the latter with an organic solvent able to extract uranium, the organic solvent comprising a system of extractants constituted by a neutral phosphine oxide and an acid organophosphorus compound.

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: Entrainment of contaminated water in the organic phase and poor phase disengagement is prevented in the second cycle scrubber, in a two cycle uranium recovery process, by washing the organic solvent stream containing entrained H.sub.3 PO.sub.4 from the second cycle extractor, with a dilute aqueous sulfuric or nitric acid solution in an acid scrubber, prior to passing the solvent stream into the second cycle stripper.

Abstract: A process for preferentially extracting and recovering vanadium and uranium from wet process acids. The wet process acid first is contacted with a neutral organo-phosphorus compound to extract the vanadium values. The resulting loaded organic phase is separated from the wet process acid due to immiscibility of the acid and organic phases. The vanadium values then are separated from the organic phase by stripping. The raffinate separated from the first organic extractant then is contacted with a second organic extractant comprising a dialkylphosphoric acid and a neutral organo-phosphorus compound to extract the uranium values. The resulting loaded organic phase is separated from the wet process acid due to immiscibility of the acid and organic phases. The organic phase is stripped with a reductive stripping solution and the stripping solution then is oxidized to convert the uranium values to the hexavalent oxidation state.

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 in wet-process phosphoric acid is extracted with an organic extractant. The pregnant extractant is then centrifuged to separate contaminants from the extractant. Secondary emulsions obtained by separating the contaminants following centrifugation are mixed with water or an acid leaching solution. After mixing, the mixture is centrifuged to separate and recover extractant which is recycled for stripping.

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: A modified liquid-liquid extraction system is disclosed in which a particulate solid and a liquid, both insoluble in a second liquid, are mixed to form agglomerate particles which efficiently extract metal ions from dilute solutions. The extraction is rapid and requires a much lower volume of extracting phase for good contacting than conventional liquid-liquid extraction. Mixing energy is low, clean-up of effluent water is easily accomplished and metal values are readily stripped from the agglomerates by well-known techniques, such as treatment by aqueous acid solution.

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: Uranium is extracted from phosphoric acid with organophosphorus extractants supported or impregnated on polymeric resins, and especially macroreticular resins. Suitable extractants include mono and dialkylphenyl esters of phosphoric acid. Uranium may be stripped from the supported or impregnated resins with hotter or more concentrated phosphoric acid, optionally with oxidation to hexavalent form, or with aqueous fluoride solutions.

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: 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: A nuclear fuel processing solution containing (1) hydrocarbon diluent, (2) tri-n-butyl phosphate or tri-2-ethylhexyl phosphate, and (3) monobutyl phosphate, dibutyl phosphate, mono-2-ethylhexyl phosphate, di-2-ethylhexyl phosphate, or a complex formed by plutonium, uranium, or a fission product thereof with monobutyl phosphate, dibutyl phosphate, mono-2-ethylhexyl phosphate, or di-2-ethylhexyl phosphate is contacted with silica gel having alkali ions absorbed thereon to remove any one of the degradation products named in section (3) above from said solution.

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: 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: The invention concerns a method for the liquid/liquid extraction of uranium from phosphoric acid with the aid of alkylamine polyphosphate and/or alkylamine metaphosphate compounds, dissolved in organic solvents insoluble in water. The uraniferous phosphoric acid is brought into contact with an organic phase compound of a long-chain alkylamine polyphosphate and/or alkylamine metaphosphate compound and an organic solvent, the alkylamine in the alkyl residue containing 8 to 30, preferably 8 to 18 C-atoms corresponding to the formula ##STR1## wherein R.sub.1 and R.sub.2 denote hydrogen or alkyl radicals and R.sub.3 denotes an alkyl radical, the polyphosphate and/or metaphosphate residue having 2 to 10,000 P-atoms per molecule and being of the straight-chain and/or linked-chain or cyclic chain type. The uranium is transferred from the aqueous into the organic phase from which the uranium is re-extracted in the known way.

Abstract: The invention concerns a method for the liquid/liquid extraction of uranium from phosphoric acid with the aid of alkylamine polyphosphate and/or alkylamine metaphosphate compounds, dissolved in organic solvents insoluble in water, in the presence of Fe.sup.II ions.The uraniferous phosphoric acid is brought into contact with an organic phase. The organic phase is composed of a long-chain alkylamine polyphosphate and/or alkylamine metaphosphate compound and an organic solvent, the alkylamine in the alkyl residue containing 8 to 30, preferably 8 to 18 C-atoms corresponding to the formula ##STR1## R.sub.1 and R.sub.2 denoting hydrogen or alkyl radicals and R.sub.3 alkyl radicals, the polyphosphate and/or metaphosphate residue having 2 to 10,000 P-Atoms per molecule and being of the straight-chain and/or link-chain or cyclic type. The uranium is transferred from the aqueous into the organic phase from which the uranium is reextracted in the know way.

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: Precipitation of Fe.sub.3 HN.sub.4 H.sub.8 (PO.sub.4).sub.6 is prevented in the second cycle extractor, in a two cycle uranium recovery process, by washing ammonia laden organic solvent stream, from the second cycle stripper, with first cycle raffinate iron stream containing phosphoric acid, prior to passing the solvent stream into the second cycle extractor.

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: 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: Methods for control of excessive corrosion in wet process phosphoric circuits are effected by oxidation of reduced ion species in the acid with maintenance of EMF value of the acid above about 190 millivolts (S.C.E. reference) through the digestion circuit. Supplementary monitoring is by a ceric red-ox titration procedure. In one embodied form, the present invention is utilized to control corrosion in a phosphoric acid plant digestion system (and subsequent processing equipment) operating by a dihydrate (gypsum) process even when such a process employs a calcined western U.S. phosphate ore feed from a relatively highly carbonaceous ore. The invention is also applicable for treating wet process phosphoric acid in phosphoric acid plants having a digester system operating by a hemihydrate process.

Abstract: A process for separating by means of an organic agent the uranium and the molybdenum contained in an aqueous liquor originating from a sulphuric attack of an urano-molybdeniferous ore which involves placing the said attacking liquor in contact with an organic extraction solution containing at least one tertiary or secondary amine in an (amine)/(Mo) molar ratio of up to 0.8, separating the molybdenum-charged organic phase from the uranium-rich aqueous phase, treating the organic phase with an aqueous liquor containing at least one mineral agent in the form of alkaline and ammonium hydroxide and/or carbonates to form an aqueous solution which is concentrated in molybdate.

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: 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 organic solvent comprises a system of extractants constituted by an acid organophosphorus compound and by a neutral phosphine oxide of formula: ##STR1## in which the radicals R.sub.1, R.sub.2 and R.sub.3 are identical or different alkyl, aryl or alkoxyalkyl radicals, at least one of the radicals R.sub.1, R.sub.2 and R.sub.3 being an alkoxyalkyl radical.

Abstract: A process is described for extracting phosphoric acid and metal values, such as uranium, from phosphate rock using hydrochloric acid and independently extracting the phosphoric acid and metal values from a slurry of the acidulated rock.

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: The oxidation and extraction steps in the vanadium stripping process (e.g., the DEPA-TOPO or DOPPA-TOPO process) are carried out simultaneously for recovering vanadium from 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: Uranium in wet-process phosphoric acid in the tetravalent state is extracted with an alkylphenyl acid phosphate extractant. The uranium in the pregnant extractant is then oxidized to the hexavalent state and stripped with a phosphoric acid stripping solution. Hydrolysis of the extractant is decreased by decreasing the proton concentration of the extractant which results from acidic impurities, e.g., sulfuric acid and fluorosilicic acid, originally present in the wet-process phosphoric acid. The proton concentration of the extractant is reduced indirectly by treating the phosphoric acid strip solution (1) with reagents which react with the acidic impurities to form water and an insoluble precipitate which is removed from the stripping solution; (2) with reagents to neutralize the acidic impurities in the stripping solution; or (3) by passing the stripping solution through a suitable ion exchange column.

Abstract: The instant invention relates to a process for removing a species from a fluid which comprises (a) contacting said fluid with a hollow microcapsule, said microcapsule having a wall surrounding an internal void, said wall being substantially insoluble in said fluid and said species being permeable to said wall; (b) permeating said species through said wall into said void; (c) converting said permeated species, in said void into a species which is impermeable to said wall; (d) separating said microcapsule from said fluid; (e) converting the impermeable species of step (c) into a species which is permeable to said wall; and (f) permeating the permeable species of step (e) through said wall. Preferably said void contains a reagent which together with said permeated species form a reversible oxidation-reduction couple. In the instant preferred embodiment said permeated species is converted into an impermeable species by means of said oxidation-reduction reaction to trap said impermeable species in said void.

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: Process for the separation of americium from curium contained in an aqueous nitric solution, wherein the initial solution undergoes oxidation at ambient temperature in the presence of phosphoric acid or phosphate ions at a concentration at the most equal to 0.1 mol per liter in such a way as to pass the americium at valency VI, the thus treated solution is brought into contact with a slightly reducing organic solvent having a high affinity for americium at valency VI in such a way as to extract the americium in the organic phase, the organic phase containing the americium at valency VI is then washed, followed by the re-extraction of the americium in the organic phase by means of an aqueous solution.

Abstract: Aqueous phosphoric acid solutions containing uranium values are contacted with an organic solution of a mixture of organophosphorus compounds produced from a carboxylic acid and PCl.sub.3 in the presence of water or from corresponding acid halides or anhydrides and phosphorous acid to extract the uranium values. The organophorus compounds generally include an alkane-1,1,2-triphosphonic acid or a 1-hydroxy-1,1-alkanediphosphonic acid or both, which differ from common organophosphorus extractants in having a carbon-phosphorus bond. The extraction has high distribution coefficients even when the phosphoric acid solution is 10 molar or more and even when the extraction is conducted at elevated temperatures such as 60.degree. C. While distribution coefficients in the presence of iron are higher for tetravalent uranium, efficient extraction can be conducted of hexavalent uranium as well.

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: This present invention provides a process of recovering uranium from a uranium-containing acid lixiviation solution comprising extracting the lixiviation solution with an organic extractant comprising an organic diluent, a dialkyl pyrophosphoric acid, and a stabilization agent, and treating the mixture of solutions as follows:(a) bubbling anhydrous ammonia gas into the solution mixture to precipitate the ammonium salt of excess dialkyl pyrophosphoric acid; and(b) separating the precipitate from the solution and recovering the uranium from the solution.

Abstract: Organic substances are removed from a highly ionic medium by contacting the medium with a substantially hydrophobic polystyrene type resin. This process is especially useful in the hydrometallurgical processes for the removal of organic substances from highly ionic raffinates prior to the recycle of the raffinate into the hydrometallurgical process.

Abstract: The invention describes the extraction of values, especially metal values such as copper and uranium, from minerals by passing the mineral in admixture with a leaching agent for the values through a contactor and extracting the values with an extractant stream immiscible with the mixture and of lesser density so that the values are captured by the extractant and can be withdrawn with the extractant and, if desired, isolated by any suitable means.

Abstract: Uranium values are recovered as uranyl peroxide from wet process phosphoric acid by a solvent extraction-precipitation process. The preferred form of this process comprises a first solvent extraction with DEPA-TOPO followed by reductive stripping of the extractant with Fe.sup.++ - containing phosphoric acid. After reoxidation, the uranium-containing aqueous stripping solution is extracted again with DEPA-TOPO and the pregnant organic is then stripped with a dilute ammonium carbonate solution. The resulting ammonium uranyl tricarbonate solution is then acidified, with special kerosene treatment to prevent wax formation, and the acidified solution is reacted with H.sub.2 O.sub.2 to precipitate a uranyl peroxide compound.