Method of extraction-type separation of americian and curium
FIELD: radiochemistry; analytical chemistry.
SUBSTANCE: proposed method consists in treatment of solution containing elements to be separated, diethylene triamine, pentaacetic acid, carbamide or formic acid, extracting agent in form of solution of chlorinated cobalt dicarbollide and polyethylene glycol in organic solvent or solution of cobalt dicarbollide, zirconium slat of dibutyl phosphoric acid and polyethylene glycol in organic solvent. Americian passes into organic solution at higher degree as compared with curium. Proposed method takes into account factor of separation of americian and curium and facilitates the process due to avoidance of salting-out agent.
EFFECT: enhanced efficiency.
4 cl, 2 tbl, 2 ex
The invention relates to the field of radiochemistry and, in particular, to the field of extraction of the allocation of long-lived radionuclides from spent nuclear fuel and irradiated targets and can be used in analytical chemistry for separation and concentration of elements
Known methods of separating americium and curium, including precipitation, sorption and extraction processes [1 Penniman, Tkined. Radiochemistry of americium and curium. M: Foreign literature; 1961; M.Kamoshida, T.Fukusava in Global-99; radiochemistry t, No. 2, s, 1979].
The disadvantages of these methods is either the complexity of the process or lack of radiation and chemical resistance of the used extractants or sorbents or low degree of separation of these elements during one stage of extraction, which requires the implementation process on a large number of stages of extraction with careful control of the flow ratio of organic and aqueous phase.
The closest technical solution to the claimed invention is a method of extraction separation of americium and curium extractant based on amines or their salts in non-polar solvents using complexing agents diethylenetriaminepentaacetic acid - DTPA [Vmichael, Eaasily, Ragusano. Technology transplutonium elements. SSC RF RIAR, 2000 THE, s.].
How is that an aqueous solution containing americium and curium visivel-nitrate lithium, sodium or aluminum, complexing agents-diethylenetriaminepentaacetic acid-DTPA, in contact with the extractant is an organic solution of amine or its salt with nitric acid. While americium passes into the organic solution to a greater extent than curium. The ratio of the distribution coefficients of americium and curium - separation factor judge about the efficiency of the separation process elements. The higher the value of the separation factor, the higher the efficiency of the process of extraction separation of americium and curium and the smaller is the number of stages of extraction required to achieve the necessary figures for cleaning one element from another.
The disadvantage of this method is that the separation of americium and curium necessary additive of vicariates - lithium nitrate or aluminum, which complicates subsequent treatment with an aqueous solution of the highlighted item. In addition, the achieved degree of separation of americium and curium(βAm/Cm) is relatively low and in most cases (βAm/Cm≤4), therefore, for an effective separation requires a sufficiently large number of stages of extraction.
The objective of the invention is to increase the efficiency of the process extracti the frame separation of americium and curium by increasing the values of their separation factor and simplify the process by eliminating from it vicariates.
The problem is solved by contact of an aqueous solution containing americium and curium, diethylenetriaminepentaacetic acid and urea or formic acid in an amount of 20-100 g/l with a solution of chlorinated cobalt dicarbollide - HDC and polyethylene glycol - PEG in an organic solvent containing components of 0.05-0.3 mol/l and 0.001 to 0.15 mol/l, respectively. While americium passes into the organic solution to a much greater extent than curium, resulting in efficient separation of these elements. As the organic solution can also be used a solution of chlorinated cobalt dicarbollide, zirconium salt dibutylamino acid - CA DBFC and polyethylene glycol in an organic solvent with the concentration of components of 0.05-0.3 mol/l, 0.1-0.5 mol/l, 0.001 to 0.15 mol/l, respectively. As the organic solvent can be used in a polar organic solvent or mixture of polar and nonpolar solvents.
The influence of the composition of the aqueous solution on the distribution of americium III and curium III extractant based HTC and PEG are shown in table 1. Organic phase: 0.3 mol/l HDC, 6% PEG in a mixture of polar and nonpolar solvents orthonitrophenol-Hexachlorobutadiene-(1:1)
|The table is a 1|
|Urea, g/l||DTPA, g/l||The distribution coefficients||The separation factor|
|Am III||Cm III||(βAm/Cm)|
The influence of the composition of the aqueous solution on the distribution of americium III and curium III extractant composition: 0.05 mol/l HDC, 0.5% PEG, 0.07 mol/l CA DBFC in polar solvent mechanicalinternational shown in table 2.
|DTPA, g/l||Urea, g/l||Formic acid, g/l||The distribution coefficients||The separation factor|
|Am III||Cm III||(βAm/Cm)|
|4||50||0,35||being 0.036||the 9.7|
CA DBFC - zirconium salt dibutylamino acid is added to the extractant to increase the degree of extraction of rare earth and transplutonium elements.
Compared with the prototype allows to simplify the process of extraction separation of americium and curium due to a significant increase in their separation factor and not using vicariates.
. Method of extraction separation of americium and curium by extraction of americium from aqueous solution containing diethylenetriaminepentaacetic acid, characterized in that the extractant use a solution of chlorinated cobalt dicarbollide and polyethylene glycol in an organic solvent or a solution of chlorinated cobalt dicarbollide, zirconium salt dibutylamino acid and polyethylene glycol in an organic solvent, and the initial aqueous solution contains urea or formic acid.
2. The method according to claim 1, characterized in that the organic solvent used polar organic solvent or mixture of polar and non-polar solvent.
3. The method according to claim 1, characterized in that the concentration of chlorinated cobalt dicarbollide, zirconium salt dibutylamino acid and glycol in the extractant 0.05-0.3 mol/l, ≤0.5 mol/l and 0.001 to 0.15 mol/l, respectively.
4. The method according to claim 1, characterized in that the concentration of urea or formic acid in aqueous solution is from 20 to 100 g/l
FIELD: processing uranium-containing products formed at extraction of uranium from solutions followed by re-extraction by means of ammonium carbonates; extraction of uranium and accompanying valid components from ores.
SUBSTANCE: proposed method includes thermal dissociation at sedimentation of uranium, entrapping of ammonia and carbon dioxide from waste gases. Thermal dissociation of uranium-containing ammonium carbonate solutions is performed at temperature of 70-85°C to pH= 6.5-5.9 at simultaneous blowing of gases by air; solutions obtained after thermal dissociation are separated from uranium-containing sediment and accompanying valid components, molybdenum for example are extracted from them.
EFFECT: enhanced efficiency of utilization of ammonia and carbon dioxide; high degree of separation of uranium and admixtures; extraction of accompanying valid components, molybdenum for example.
2 cl, 1 tbl, 2 ex
FIELD: hydraulic metallurgy.
SUBSTANCE: method comprises extracting saturated ionite from the pulp, washing it with water, desorbing uranium, washing desorbed ionite to decrease acidity, separating by wet screening into 1.0±0.2-mm size, extracting silicon from the under-screen product, and discharging it and above-screen product to the uranium sorption.
EFFECT: reduced ionite consumption.
1 cl, 1tbl
SUBSTANCE: extractant has bi-phosphorus acid and additionally has tri-phosphate with relation of said components (0,5-1,25):1. Method for producing extractant includes adding to 2-ethylhexanole of chlorine oxide of phosphorus with their relation (4,5-5,1):2,0, and with parameters determined by reaching fullness of passing of reaction, after that reaction mixture is exposed until full removal of formed chlorine hydrogen, then to received mixture 1 mole of water is added, mixture is exposed to full hydrolysis. Then mixture is washed ad water layer is separated from organic remainder, containing said bi-phosphoric acid and tri-phosphate.
EFFECT: higher efficiency.
2 cl, 1 dwg, 2 tbl, 4 ex
FIELD: uranium technologies.
SUBSTANCE: method comprises sorption of uranium on low-basicity anionites, desorption of uranium, and recovery of finished product. In particular, uranium-saturated low-basicity anionite is converted into OH- form and uranium into soluble stable complex [UO2(CO3)3]-4 by treating sorbents with alkali metal and ammonium carbonate solutions.
EFFECT: achieved complete desorption of uranium and simultaneously sorbent is freed from poisons and other sorption components.
FIELD: reprocessing of worked-out equipment, contaminated with radioactive impurities.
SUBSTANCE: claimed method includes deactivation of contaminated equipment in assembly, disassembling, fragmentation, separation of surface-contaminated fragments, deactivation thereof, classification of metal kinds and groups, and acceptance of mechanical and physical alterations. Fragments satisfied to acceptance results are deactivated without changing form and metal structure thereof and separated into fragments for direct application and for technological update. Fragments not satisfied to acceptance results are used as debris of metal radwastes in metallurgy to produce steel and alloys. Method for production of steel and alloys includes batch preparing, additive introducing during melting process and casting of finished metal. Necessary debris amount to produce desired chemical element content in specific grade of steel or alloy is predetermined followed by calculation of dilution coefficient and upper limit value of debris specific activity. Then debris with specific activity of not more than calculated upper limit value is fed in founding as the base metal and/or addition alloy.
EFFECT: simplified and economy reprocessing method; increased metal amount recycled into national economy, and reduced solid radwaste amount.
3 cl, 2 ex
FIELD: chemical technology; deactivation and decontamination of radioactive industrial products and/or wastes.
SUBSTANCE: proposed method designed for deactivation and decontamination of radioactive industrial products and/or production wastes incorporating Th-232 and its daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Al, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like and that ensures high degree of coprecipitation of natural radionuclides of filtrates, confining of radioactive metals, and their conversion to environmentally safe form (non-dusting water-insoluble solid state) includes dissolution of wastes, their treatment with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9-10 in the amount of 120-150% of that stoichiometrically required for precipitation of total content of metal oxyhydrate; then pulp is filtered and barium chloride is injected in filtrate in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp and pre-dissolved in sulfuric acid of chlorine compressors spent 5-20 times in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2. Then lime milk is added up to pH = 11 - 12 and acid chloride wash effluents of equipment and production floors are alternately introduced in sulfate pulp formed in the process at pulp-to-effluents ratio of 1 : (2-3) to pH = 6.5 - 8.5. Filtrate pulp produced in this way is filtered, decontaminated solution is discharged to sewerage system, sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization, inert filler and 0.5 - 2 parts by weight of calcium sulfate are introduced in pasty mixture while continuously stirring them. Compound obtained in the process is placed in molds, held therein at temperature of 20 - 50 oC for 12 - 36 h, and compacted in blocks whose surfaces are treated with water-repelling material.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes.
8 cl, 1 dwg, 1 ex
FIELD: chemical technology; recovery of deactivated and decontaminated radioactive industrial wastes.
SUBSTANCE: proposed method that can be used for deactivating and decontaminating industrial radioactive wastes incorporating Tb-232 and their daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Sl, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like includes dissolution of wastes, treatment of solutions or pulps with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9 - 10 in the amount of 120-150% of total content of metal oxyhydrates stoichiometrically required for precipitation, pulp is filtered, and barium chloride in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp, as well as pre-diluted sulfuric acid spent 5 - 20 times in chlorine compressors in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2 are introduced in filtrate. Alternately introduced in sulfate pulp formed in the process are lime milk to pH = 11 - 12, then acid chloride wash effluents from equipment and industrial flats at pulp-to-effluents ratio of 1 : (2 - 3) to pH = 6.5 - 8.5, and pulp obtained is filtered. Decontaminated solution is discharged to sewerage system and sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization process; then 35 - 45 mass percent of inert filler, 10 - 20 mass percent of magnesium oxide, and 15 -m 25 mass percent of magnesium chloride are introduced in pasty mixture formed in the process while continuously stirring ingredients. Compound obtained is subjected to heat treatment at temperature of 80 - 120 oC and compressed by applying pressure of 60 to 80 at.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes due to enhanced coprecipitation of natural radionuclides.
7 c, 1 ex
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
FIELD: inorganic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for combined precipitation of actinides of the different oxidation degree (IV) wherein a selective chelating agent consisting of oxygen, carbon, nitrogen, hydrogen or carboxylic acid is added to aqueous solutions containing actinides in the oxidation degree (IV) followed by carrying out simultaneous precipitation of at least two complex compounds of actinides and precipitate is calcined. Prepared mixed actinide oxides of the oxidation degree (IV) can be used in producing the nuclear fuel.
EFFECT: improved preparing method.
24 cl, 1 tbl, 5 ex
SUBSTANCE: hydroxylamine is introduced into 0.5-3 M, preferably 1-2.5 M, nitric acid solution containing mixture of plutonium with different valence, namely Pu(VI), Pu(IV), and Pu(III). Solution is conditioned at 20-40°C, preferably at 25-35°C during period sufficient to reduce Pu(VI) to Pu(IV). Then nitric acid concentration is adjusted to 2.5-4 M, preferably to 2.5-3 M and solution is conditioned at 20-40°C up to step-like increasing of redox potential (namely to +0.84-+0.87 V), measured using silver chloride reference electrode. In another embodiment of the invention in nitric acid solution containing mixture of plutonium with different valence, namely Pu(VI), Pu(IV), and Pu(III) nitric acid concentration is adjusted to 2-4 M, hydroxylamine is introduced and solution is conditioned at 20-40°C up to step-like increasing of redox potential (namely to +0.84-+0.87 V), measured using silver chloride reference electrode.
EFFECT: accelerated method for chemical tetravalent plutonium stabilization; decreased process step number, reduced heat consumption, and decreased radioactive gases and aerosol release.
4 cl, 6 ex, 3 dwg
FIELD: production of plutonium and its compounds.
SUBSTANCE: the invention is pertaining to the field of production of plutonium and its compounds. The device is intended for the continuous transformation of plutonium oxalate into plutonium oxide by means of its drying with the following calcination. The device represents a cylindrical form kiln equipped along its longitudinal horizontal axis with a feed screw of a screw auger type. The feed screw at its rotation around of the horizontal axis ensures transportation of a product subjected to the thermal treatment from the feed zone of the kiln where it was subjected to a drying, to the second zone where it is subjected to a calcining. The furnace body has a window for plutonium oxalate charging into the body from the feed zone side, a window for plutonium oxide unloading from the body on the other end from the second zone side, for oxygen blowing into the internal space of the kiln and for withdrawal of the gases from the kiln. Within the limits of the body thickness there are cavities with a capability to locate in them with access from the front side of a glove chamber, tubular heaters. The heaters represent at least one short tubular heater and at least one long tubular heater. The short tubular heater is intended to provide a fractional drying of plutonium oxalate in the feed zone of the kiln, and the long tubular heater is intended to provide simultaneously the fractional drying of plutonium oxalate in the feed zone of the kiln and calcinations of plutonium oxalate in the second zone of the kiln. Besides the furnace body contains a means for withdrawal of gases from the kiln through a hole for the gases withdrawal, with keeping rarefaction in it, and also a unit of filtration. The unit of filtration contains a battery composed of the filtrating plugs mounted in parallel to each other and intended for removal of dust of solid particles caught by a gases flow. Each filtrating plug contains a rigid filter medium and is linked with a nozzle means of cleanout of the indicated rigid filtering medium from a stocked deposit of the particles.
EFFECT: the invention ensures continuous transformation of plutonium oxalate into plutonium oxide.
6 cl, 2 dwg
FIELD: reprocessing and utilization of solid radioactive waste from atomic industry.
SUBSTANCE: plutonium is recovered from fiberglass aerosol boron-containing filter by alkaline opening of spent filtering material in presence of magnesium-containing reagent (e.g., magnesium carbonate) in mass ratio not less than 0.85 as calculated to magnesium and boron oxides. Then insoluble precipitate is treated with mixture of aqueous nitric and hydrofluoric acids. Obtained solution is purified from impurities by sorption method. Plutonium oxalate is deposited from purified solution and burned to obtain plutonium dioxide.
EFFECT: plutonium product with small boron content.
2 cl, 1 tbl, 5 ex
FIELD: analytical chemistry, in particular method for tin (II) detection.
SUBSTANCE: claimed method includes tin (II) isolation from solution with pyrocatechin violet as complexation agent and mixture of hexyldiantipyrilmethane and benzoic acid in ratio of 1:1.0-2.0 as extractant and complexation agent in presence of hydrochloric acid followed by quantitative registration by spectrophotometric method.
EFFECT: simplified and safe assay method.