Metallic uranium obtaining method
SUBSTANCE: metallic uranium obtaining method involves electrolysis of uranium dioxide in the melt of lithium and potassium chlorides in an electrolysis unit with a graphite anode and a metal cathode and release of metallic uranium on the cathode and carbon dioxide on the anode. First, mixtures of uranium dioxide and carbon are prepared in molar ratio of 6:1 and 1:1 by crushing the corresponding powders; the obtained powders are briquetted into pellets. To the anode space of the electrolysis unit, which is formed with a vessel with porous walls, which is arranged in a ceramic melting pot, there loaded are pellets obtained from mixture of uranium dioxide and carbon, and melt of lithium and potassium chlorides. To the cathode space of the electrolysis unit, which is formed with the vessel walls with porous walls and the ceramic melting pot, there loaded is melt of lithium and potassium chlorides and uranium tetrachloride in the quantity of 5-15 wt % of lithium and potassium chlorides. Electrolysis is performed at the electrolyte temperature of 500-600°C, cathode density of current of 0.5-1.5 A/cm2, anode density of current of 0.05-1.5 A/cm2, in argon atmosphere with periodic loading to anode space of pellets of mixture of uranium dioxide and carbon.
EFFECT: current yield of metallic uranium is 80-90% of theoretical.
A promising fuel for fast reactors is dense uranium-plutonium fuel with a density greater than the density of oxide fuel. For the synthesis of dense fuel, you can use metallic uranium and plutonium. In a prospective NPP nuclear fuel cycle the final products of the reprocessing of irradiated nuclear fuel is metallic uranium and plutonium. Currently, the final products of the reprocessing of irradiated nuclear fuels are the oxides of uranium and plutonium, therefore, for the synthesis of dense fuel required conversion of the oxides of uranium and plutonium in metallic phase.
The invention relates to methods of producing uranium metal for solid fuel power reactors.
Known metallocherpitsy the method of obtaining uranium metal, which consists in the recovery of uranium oxides or halides derived from oxides) metallic calcium or magnesium (V.B. have been Shevchenko, BN. Sudarikov. The technology of uranium. Gosatomizdat, M., 1961, SS-308). The method is inefficient for the production of fuel from power reactors.
The metal can be obtained by electrolysis of molten salts of uranium. The known method the electrolytic production of metallic uranium from molten uranium tetrafluoride or salts of uranium tetrafluoride with what tridom potassium KUF5 (tetrachloride uranium on an industrial scale in this way is not used), placed in molten chlorides of calcium and sodium (V.B. have been Shevchenko, BN. Sudarikov. The technology of uranium. Gosatomizdat, M., 1961, SS-311). Uranium is allocated at the cathode and at the anode aggressive fluorine, which binds the calcium chloride with the liberation of chlorine - aggressive gas, which is necessary to bind chemically neutral connection.
The known method the electrolytic production of uranium metal from uranium oxides (U.S. Patent No. 7638026, IPC SS 3/34, publ. 29.12.2009) prototype. According to the method of spent nuclear fuel in the form of uranium dioxide is mixed with uranium tetrachloride UCl4and placed in the molten LiCl. The lithium chloride may also be in combination with potassium chloride KCl and trichlorides uranium UCl3. Uranium dioxide to uranium tetrachloride is placed in the anode space of the cell, separated from the cathode space by porous partition.
In the method using a metal cathode and a graphite anode, while the cathode gives the uranium, and the anode is carbon dioxide CO2. Carbon dioxide in the process of electrolysis is formed due to the interaction of the anode material or carbon contained in the scrap tablets oxide fuel, oxygen-containing particles of the electrolyte (UO2+). Interaction with the material of the anode leads to the dissolution of the anode and the need hosamani after some time. Scrap tablets does not provide a stable and fast enough carbon in the electrolyte.
Electrolysis bath also contains additional protective cathode, positioned between the anode space and the main cathode (the cathode, which is obtained uranium metal), while the voltage between the anode and the additional cathode provide passage through a porous wall only ions of trivalent uranium, while particles UCl4remain in the anode space. On the secondary cathode is recovered, the tetravalent uranium to trivalent, and the main cathode subsequent recovery of trivalent uranium to U0.
The objective of the invention is to develop an easier way for the electrolytic production of uranium metal from uranium dioxide.
The task is solved by the fact that in a method of producing uranium metal, including the electrolysis of uranium dioxide in molten chlorides of lithium and potassium in the cell with a graphite anode and a metal cathode and isolation of uranium metal at the cathode and carbon dioxide at the anode, pre-prepared mixture of uranium dioxide and carbon in a molar ratio of 6:1 and 1:1 by grinding powder of uranium dioxide powder and carbon black or graphite as carbon to a particle size of 1-10 μm. the ATEM bitteroot obtained powders into tablets weighing 5-10 g
In the anode space of the cell formed by the vessel with porous walls, placed in a ceramic crucible, download the tablets obtained from a mixture of uranium dioxide and carbon in a molar ratio of 6:1, and the melt of lithium chloride and potassium taken in a molar ratio of 3:2, when the mass ratio of uranium dioxide to lithium chloride and potassium 1:1.
In the cathode space of the cell formed by the walls of the vessel with porous walls and a ceramic crucible, download a melt of lithium chloride and potassium at a molar ratio of 3:2 and uranium tetrachloride in the amount of 5-15 wt.% from the chlorides of lithium and potassium.
The electrolysis is carried out at a temperature of the electrolyte 500-600°C., a cathode current density of 0.5 to 1.5 a/cm2and anodic current density of 0.05-1.5 a/cm2in an argon atmosphere with periodic loading in the anode space of tablets from a mixture of uranium dioxide and carbon in a molar ratio of 1:1.
The method is as follows.
Prepare a mixture of uranium dioxide and carbon. As carbon use graphite powder or carbon black. The carbon powder and powdered uranium dioxide are mixed in a molar ratio of 6:1 or 1:1, i.e. in a sixfold excess of carbon to uranium dioxide or in the stoichiometric ratio of the final reaction interaction: UO2+=U+CO2. The mixture is placed in a ball mill; about swagat grinding the mixture to a particle size of 1-10 μm, when this happens the homogenization of the mixture. The first mixture (a mixture of carbon and uranium dioxide in a molar ratio 6:1) prepare for the first load in the cell, the second mixture (molar ratio 1:1) for subsequent downloads in the electrolysis process. The mixture bitteroot into tablets weighing 5-10 g
The use of carbon mixed with uranium dioxide and grinding the mixture to a particle size of 1-10 μm provides an output of uranium metal current up to 80-90% of theoretical (for comparison: when using particles with a size of 200 μm, the current output is 16-20%).
Tablets first mixture of uranium dioxide with carbon added to the salt mixture composition: lithium chloride - potassium chloride, taken in a molar ratio of 3:2, the mixture of chlorides charge / mass ratio to uranium dioxide 1:1.
The resulting mixture is placed in a vessel with porous walls (in the prototype is a vessel 12, the vessel is placed in a ceramic crucible. In a vessel with porous walls is a graphite anode (anode space of the cell), and in the crucible, outside the vessel, and a metal cathode (cathode space of the cell). The porous walls of the vessel are porous partition separating the anode space of the cell from the cathode space. Porous partition permeable to ions, including ions of uranium (U4+and chloride. Cat is the initial compartment is filled with a mixture of lithium chloride with potassium chloride, taken in a molar ratio of 3:2, to which is added the uranium tetrachloride in the amount of 5-15 wt.% from the mixture of chlorides in the cathode compartment.
The uranium tetrachloride is placed in the cathode space once when you first load cell, the electrolysis process it is produced in the anode space. (Unlike the prototype, in which the process is conducted in the presence of uranium tetrachloride only in the anode space, the proposed method in the presence of uranium tetrachloride in the cathode and anode spaces in the proposed method there is no additional protective cathode that simplifies the way). Consumable in the electrolysis of uranium dioxide and carbon periodically added to the anode compartment at the stoichiometric ratio (in the form of tablets of the second mixture in the anode space is saved sixfold excess carbon from stoichiometry), creating a ratio of a mixture of uranium dioxide with carbon to a mixture of lithium chloride and potassium in the anode space of 1:1.
The cell is placed in a sealed apparatus, vacuum to a residual pressure of 10-2mm Hg, the apparatus is filled with argon, the electrolyte is heated to 500÷600°C, while the melting of the electrolyte. The process is carried out at a temperature of 500÷600°C, cathode current density of 0.5÷1.5 a/cm2, anode current density of 0.05÷1.5 a/cm2. Rising the temperature above 600°C leads to the reduction of uranium due to its dissolution and separation of uranium tetrachloride. At temperatures below 500°C increases the viscosity of the electrolyte, which leads to lower current output.
A graphite anode is a non-consumable element of the cell.
At the anode, and near him, apparently, the chloride ion is oxidized to elemental chlorine which reacts with uranium dioxide and carbon, giving the uranium tetrachloride and carbon dioxide. Carbon dioxide away from the anode space and sent for recycling. Chlorine is an intermediate product and is consumed in the process.
The source of uranium metal, which is deposited on the cathode due to the reduction reaction of U4++4E-=U0is uranium tetrachloride formed from uranium dioxide in the anode space. The accumulation of the metal cathode is removed from unit, remove the metal, the cathode is used again. Metal residue purified from the electrolyte melt in a compact metal and further use in the preparation technology of reactor fuel.
The method of obtaining uranium metal, including the electrolysis of uranium dioxide in molten chlorides of lithium and potassium in the cell with a graphite anode and a metal cathode and isolation of uranium metal at the cathode and carbon dioxide on the anode, wherein the pre-prepared mixture of uranium dioxide and the carbon is in a molar ratio of 6:1 and 1:1 by grinding powder of uranium dioxide powder and carbon black or graphite as carbon to a particle size of 1-10 μm, bitteroot obtained powders into tablets weighing 5-10 g in the anode space of the cell formed by the vessel with porous walls, placed in a ceramic crucible, download the tablets obtained from a mixture of uranium dioxide and carbon in a molar ratio of 6:1, and the melt of lithium chloride and potassium taken in a molar ratio of 3:2, when the mass ratio of uranium dioxide to lithium chloride and potassium 1:1, and in the cathode space of the cell formed by the walls of the vessel with porous walls and a ceramic crucible, download a melt of lithium chloride and potassium at a molar ratio of 3:2 and the uranium tetrachloride in the amount of 5-15 wt.% from the chlorides of lithium and potassium, the electrolysis is carried out at a temperature of the electrolyte 500-600°C., a cathode current density of 0.5 to 1.5 a/cm2, anode current density of 0.05-1.5 a/cm2in an argon atmosphere with periodic loading in the anode space of tablets from a mixture of uranium dioxide and carbon in a molar ratio of 1:1.
SUBSTANCE: continuous layers of silicon are obtained by electrolysis of potassium hexafluorosilicate (K2SiF6) in melt of the following composition, wt %: KCl (15÷50) - KJF (5÷50) - (10÷35) K2SiF6. Electrolysis is performed at temperature 650 - 800°C, cathode current density 10 mA/cm2 - 150 mA/cm2 in air atmosphere.
EFFECT: method makes it possible to obtain silicon in form of continuous from 1 mcm to 1 mm thick layers both on flat and curved surfaces, reduce silicon loss.
SUBSTANCE: method includes electrolytic refining of lead in the melt of salt halogenides with use of liquid metal cathode and anode. At the same time the process of electrolysis is carried out with application of one and more bipolar electrode, such as liquid lead, at cathode density of current from 0.5 to 2.0 A/cm2, anode - from 0.3 to 1.5 A/cm2 and temperature of 450-600°C.
EFFECT: higher extent of raw lead treatment from admixtures.
SUBSTANCE: method involves anodic dissolution of tin and lead in a molten electrolyte of zinc, potassium and sodium chlorides, and depositing lead and tin on the wall of the cathode bath. The process is carried out while blowing the starting alloy with air and periodically adding ammonium chloride into the electrolyte by ejection feeding. The electrolysis cell has a lined heated cathode bath in which there is an anode cup with an insulated graphite current lead. The graphite current lead is hollow and has a nozzle with a channel for feeding air to the bottom of the anode cup. The graphite current lead has in its lower part a disc with air distribution channels.
EFFECT: reduced sludge formation, easier maintenance and high quality of the product.
3 cl, 1 dwg
SUBSTANCE: electrolytic cell comprises heated cathode and anode baths separated by porous diaphragms impregnated with electrolyte. The cylinder of the cathode bath is arranged as perforated, and a diaphragm from quartz fabric is fixed on it with a yoke above the perforation level. The cathode bath is vertically submerged into the melt of the initial alloy of the anode bath equipped with a mixer. Inside the cathode bath a cup is installed onto the bottom from the diaphragm and fixed on the cathode current conductor. At the same time the cathode bath cylinder is submerged into the alloy melt in the anode bath at the perforation height. The cup fixed on the cathode current conductor is installed below the cylinder perforation level. On the cylinder of the cathode bath there are two layers of the diaphragm fixed from quartz fabric.
EFFECT: higher stability of operation, higher extent of indium extraction with higher extent of separation from electric positive metals.
4 cl, 2 dwg, 1 tbl
SUBSTANCE: method in accordance with the invention may cover production of other metals that have properties similar to tungsten. The method includes removal of a substance (X) from a compound containing two or more metals (M1M2X) with the help of electrolysis. At the same time electrolysis is carried out in electrolyte of a melted salt or melted salt solution, in which a metal compound (M1M2X) does not dissolve, and in which the applied potential is below the potential of electrolyte breakdown.
EFFECT: direct application of this method with tungsten concentrates.
8 cl, 1 ex
SUBSTANCE: electrolysis is carried out in melt of sodium alkali at cathode density of current 0.3-0.7 A/cm2 and at mixing melt for purification from polonium. Bismuth produced after electrolysis is subjected to successive deep purification from lead till its content in purified bismuth is less or equal to 1·10-5 wt %.
EFFECT: increased output of purified bismuth.
SUBSTANCE: electrolyser consists of electrolysis bath, of anode, cathode and of collector of cathode lead. Also, electrolysis bath is made out of heat resistant concrete. The anode is installed in a recess of the bath and is made in form of a graphite bottom with a steel current conductor, while cathode corresponds to two cylinders out of graphite. Chutes for drain of cathode lead into collectors are arranged directly under the graphite cylinders.
EFFECT: raised efficiency of electrolyser, reduced power expenditures and labour input, raised reliability of electrolyser operation.
6 cl, 1 tbl, 2 dwg
SUBSTANCE: electrolyser consists of liquid metal anode, of cathode and bipolar electrode, of pore-free electro-conductive diaphragm positioned between cathode and anode with its lower end immersed in bipolar liquid metal electrode and electro-insulated from side of cathode.
EFFECT: reduced impurity of cathode metal, raised stability of its operation due to control over parametres of refining process.
3 cl, 1 dwg, 1 tbl
SUBSTANCE: method for extracting indium from waste alloys involves electrolytic anodic dissolution of the alloy in molten electrolyte containing zinc chloride, and indium deposition on cathode. Anodic dissolution is performed by adding to the electrolyte of 10-15 wt % of sodium chloride and 15-20 wt % of potassium chloride and with separation of initial molten anodic alloy and cathode with diaphragm consisting of two layers of quartz fabric at electrolyte consumption of 0.4-0.5 g per cm2 of fabric. The process is performed through diaphragm consisting of two layers of quartz fabric, which separates the initial molten anodic alloy and cathode. Device for extracting indium includes cathode and anodic bath with initial molten alloy; cathode is made in the form of cathodic disc freely inserted in cathodic bath in the form of cylinder with annular projection and bottom made in the form of diaphragm consisting of two layers of porous quartz fabric submerged into anodic bath, fixed with a clamp above annular protrusion on the cylinder end of cathodic bath and covered with plastic fluor.
EFFECT: reducing the costs for electrolyte and increasing indium extraction degree.
3 cl, 1 dwg, 1 tbl, 1 ex
SUBSTANCE: electrolysis is performed in melt containing (wt %): to 65CsCl, 15-50 KCl, 5-50 KF, 10-60 K2SiF6 at temperature 550-750 °C. As anode there is used material containing silicon. Also electrolysis is carried out with variation of cathode density of current from 0.005 to 1.5 A/cm2 and with successive separation of silicon deposit off surface of a cathode-substrate and electrolyte.
EFFECT: high output of finished product at relatively simple hardware implementation of process.
3 cl, 4 ex
SUBSTANCE: method involves dissolving a chemical concentrate of natural uranium in nitric acid solution, extracting and re-extracting uranium. The dissolved concentrate contains 1.2-3.7 wt % iron to uranium, 1.4-4.0 wt % sulphur to uranuim and 0-0.7 wt % phosphorus to uranium in nitric acid solution. Nitric acid and water are taken in an amount which provides the following concentration in the solution fed for extraction: uranium 450-480 g/l, iron (III) ions 0.1-0.3 mol/l, sulphate ions 0.2-0.6 mol/l, phosphate ions 0-0.10 mol/l, and free nitric acid 0.8-2.4 mol/l, and saturation of extractant with uranium during extraction is maintained in accordance with the ratio: Y ≤90.691-34.316·[SO4]+7.611·([Fe]-[PO4])+5.887·[HNO3]-9.921·[SO4]·[HNO3]+19.841·[SO4]2+7.481·([Fe]-[PO4])·[HNO3]-64.728·([Fe]-[PO4])·[SO4]+92.701·[SO4]·[HNO3]·([Fe]-[PO4])-185.402·[SO4]2·([Fe]-[PO4]), where Y is saturation of the extractant with uranium, %, and concentration in the solution fed for extraction, mol/l: [SO4] - sulphate ions, [PO4] - phosphate ions, [HNO3] - nitric acid, [Fe] - iron (III) ions.
EFFECT: obtaining raffinates with low uranium content.
SUBSTANCE: method includes sorption of rich components from production solutions by ion-exchange material counterflow under controlled pH of environment and oxidation-reduction potential Eh. Sorption is performed by ion-exchange materials in stages from production solutions containing uranium, molybdenum, vanadium and rare earth elements. At the first stage uranium and molybdenum are extracted by anion-exchange material sorption. At the second stage vanadium is extracted by anion-exchange material sorption with hydrogen dioxide available at Eh of 750-800 mV, pH of 1.8-2.0 and temperature of 60°C, at that vanadium sorption is performed till complete destruction of hydrogen dioxide and till Eh is below 400 mV. Then barren solutions are transferred to cationite at pH of 2.0-2.5 and Eh of 300-350 mV for extraction of rare earth elements.
EFFECT: sorption concentration and selective separation of uranium and molybdenum from vanadium, and vanadium from rare earth elements, and rare earth elements from iron and aluminium, intensification of sorption process, reduction of flow diagram and possibility of environmentally sound oxidants use.
1 dwg, 4 tbl, 1 ex
SUBSTANCE: processing method of black-shale ores includes crushing, counterflow two-stage leaching by sulfuric acid solution upon heating, separation of pulps formed after leaching at both stages by filtration. Then valuable soluble materials are washed from deposit at the second stage with strengthened and washing solutions being produced, marketable filtrate is clarified at the first stage for its further processing. Ore is crushed till the size of 0.2 mm, leaching at the first stage is performed by cycling acid solution with vanadium under atmospheric pressure, temperature of 65-95°C during 2-3 hours, till residual content of free sulphuric acid is equal to 5-15 g/l. Leaching at the second stage is performed at sulphuric acid rate of 9-12% from the quantity of initial hard material under pressure of 10-15 atm and temperature of 140-160°C during 2-3 hours. Cake filtered after the first stage is unpulped by part of strengthened solution which content is specified within 35-45% of total quantity.
EFFECT: high-efficiency extraction of rich components, possibility of pulps separation by filtration after leaching with high properties thus reducing costs for separation processes.
3 cl, 1 dwg, 1 tbl
SUBSTANCE: processing method of black-shale ores with rare metals extracting includes leaching of ore by sulphuric acid solution with dilution of rare metals. Leaching is performed in autoclave by sulphuric acid solution consisting of free and combined sulphuric acid with ratio of H2SO4(free):H2SO4(comb)=2:1, and containing 25-45 g/l of iron sulphate, 70-90 g/l of aluminium sulphate and 0.5 g/l of nitric acid. At that the process is performed under pressure in autoclave equal to 10-15 atm with mixing at temperature of 140-160°C in concentration range of general H2SO4(gen) equal to 350-450 g/l under pulp density S: L=1:0.7-0.9, preferably 1:0.8, under constant oxidation-reduction potential Eh in the system equal to 350-450 mV during 2-3 hours till residual concentration of free H2SO4(free) is within 45-75 g/l.
EFFECT: increasing break-down of ore and extraction of rare metals: vanadium, uranium, molybdenum and rare-earth elements, reducing consumption of acid and improving efficiency of autoclave volume usage.
1 tbl, 1 ex
SUBSTANCE: invention relates to the technology of processing chemical concentrates of natural uranium, involving leaching (dissolving) the concentrate and extracting uranium using tributyl phosphate in a hydrocarbon diluent. The method involves dissolving the concentrate using aqueous nitric acid solution, feeding the obtained aqueous uranyl nitrate solution to the extract outputting step of a stepped extraction unit and extracting uranium with tributyl phosphate in a hydrocarbon diluent. Extraction is carried out by counterflow interaction of the aqueous and organic phases. Concentrate containing thorium impurities in ratio of 1 wt % to uranium is used. During extraction at the extract outputting step, the step for saturating the extractant with uranium is kept at least 87% of the maximum saturation of the extractant with uranium, and a portion of the aqueous phase, which is not more than 60 vol. % of the uranyl nitrate solution fed to the extract outputting step, after one of the extraction steps is removed from the extraction process and fed for dissolving the uranium concentrate.
EFFECT: high extraction of uranium and nitric acid from the raffinate.
SUBSTANCE: method involves use of an unbalanced solution consisting of a solution from the washing process of anionite from the acid and filtrate from the filter press, and their removal from the process together with a mother solution from deposition of natural uranium concentrate through an additional saturation operation together with a marketable reclaimed product. For that purpose, the plant includes a local solution recirculation circuit in the form of a collector for solutions of unbalanced and mother concentrate from deposition, which is connected to pipelines of the above solutions and equipped with solution supply pipelines attaching the collector through a gravity tank to an additional saturation column from the marketable reclaimed product and to a solution return pipeline attaching the gravity tank to the solution collector of the local solution recirculation circuit.
EFFECT: reduction of nitrate ions emissions; reduction of prime cost of end product and compliance with strict environmental requirements.
2 cl, 2 dwg, 1 tbl, 2 ex
SUBSTANCE: method involves leaching of uranium and iron using sulphuric acid solution and ferric iron contained in the ore as an oxidiser. After leaching is completed, uranium is extracted from the solution so that mother solution containing ferrous iron is obtained. Then, acidification of the mother solution is performed using sulphuric acid and recovery of ferric iron is performed by oxidation of ferrous iron so that a reusable solution is obtained, and recirculation of that solution for leaching of uranium is performed. Recovery of ferric iron is performed by action on the mother solution of high-voltage pulse electric discharges at high voltage pulse amplitude of not less than 10 kV and at pulse repetition cycle at the interval of 400÷1400 pulse/sec. At that, prior to action on mother solution with high-voltage pulse electric discharges, it is subject to dispersion.
EFFECT: reduction of power consumption and capital costs.
1 dwg, 2 tbl, 1 ex
SUBSTANCE: proposed process comprises crushing and grinding the ore, sulfuric acid leaching with addition of nitrogen acid as an oxidiser. Then, uranium is extracted and cleaned of impurities with the help of extractive agents mix to wash saturated extractive agent with the solution of sulfuric acid. After extraction, uranium is re-extracted to obtain uranium concentrate by means of 8-10%-solution of sodium carbonate. Uranium is deposited from re-extracted product by hydrogen peroxide with 50-100%-surplus from stoichiometry at equilibrium pH 3.6-4.2, mixing interval of 1- 1.5 h and sedimentation time of, at least, 1 h.
EFFECT: high quality finished uranium protoxide-oxide product.
4 tbl, 4 ex
SUBSTANCE: invention relates to methods of extracting americium in form of americium dioxide from solutions. The invention can be used in the technology of extracting americium from production and radioactive wastes. The method involves concentrating nitric acid solution containing americium and impurities to americium content of not less than 100 mg/l by multi-step deposition of a precipitate containing americium, followed by dissolution thereof each time in a new portion of the starting solution. The precipitate containing americium is obtained from each portion of the solution by adding to 3.8-6.0 M nitric acid solution, which contains americium and impurities, ammonium hydroxide or an alkali metal hydroxide until achieving residual acidity of 0.1-0.2 M, oxalic acid to concentration of 10-50 g/l and adjusting acidity of the obtained reaction mixture to pH 0.6-2.3 if there are hydrolysable impurities in the starting solution and to pH 0.6-3.5 if not. The precipitate obtained by deposition from the americium-concentrated solution is then calcined and the calcined precipitate is then dissolved in nitric acid solution. Americium is then extracted from the obtained solution by a tributyl phosphate-based solid extractant, re-extracted, americium oxalate is deposited from the re-extract and then calcined to americium dioxide.
EFFECT: wider range of methods of extracting americium.
3 cl, 2 ex
SUBSTANCE: invention refers to complex processing method of carbon-silicic black-shale ores, which contain vanadium, uranium, molybdenum and rare-earth elements. The above method involves ore crushing to the particle size of not more than 0.2 mm and two leaching stages. Oxidation sulphuric-acid leaching is performed at atmospheric pressure. Autoclave oxidation sulphuric-acid leaching is performed at the temperature of 130-150°C in presence of oxygen-containing gas and addition of a substance forming nitrogen oxide, as a catalyst of oxygen oxidation. Ion-exchange sorption of uranium, molybdenum, vanadium and rare-earth elements is performed from the obtained product solution.
EFFECT: increasing extraction degree of vanadium, uranium, molybdenum; improving the complexity of ore use owing to associated extraction of rare-earth elements.
18 cl, 1 dwg
FIELD: rare, dispersed and radioactive metal metallurgy, in particular hydrometallurgy.
SUBSTANCE: invention relates to method for reprocessing of polymetal, multicomponent, thorium-containing radwastes, formed when reprocessing of various mineral, containing rare-earth elements, Nb, Ta, To, V, Zr, Hf, W, U, etc. Method includes treatment of solution and/or slurry with alkaline agent; introducing of sulfate-containing inorganic compound solution and barium chloride; treatment of obtained hydrate-sulfate slurry with iron chloride-containing solution, and separation of radioactive precipitate from solution by filtration. As alkali agent magnesia milk containing 50-200 g/dm2 of MgO is used; treatment is carried out up to pH 8-10; sodium sulfate in amount of 6-9 g Na2SO4/dm2 is introduced as solution of sulfate-containing inorganic compound; barium chloride solution is introduced in slurry in amount of 1.5-3 g BaCl2/dm2. Hydrate-sulfate slurry is treated with solution and/or slurry containing 0.8-16 Fe3+/dm2 (as referred to startingsolution) of iron chloride, followed by treatment with high molecular flocculating agent and holding without agitation for 0.5-2 h. Radioactive precipitate is separated from mother liquor, washed with water in volume ratio of 0.5-2:1; then washed with sodium chloride-containing solution and/or slurry in volume ratio of 0.5-2:1; radioactive precipitate is removed from filter and mixed with mineral oxides in amount of 0.5-0.8 kg MgO to 1 kg of precipitate. Formed pasty composition is fed in forms and/or lingots and presses with simultaneous heating up to 80-1200C.
EFFECT: filtrate with reduced radioactivity due to increased codeposition coefficient of natural Th-232-group radioactive nuclide, in particular Ra-224 and Ra-228, with radioactive precipitates.
10 cl, 1 ex