Method of extracting radionuclides and microelements
SUBSTANCE: invention relates to the field of the sorption technology for the extraction of radionuclides and microelements in processing of various liquid and solid objects of radio-chemical enterprises. The claimed method includes a contact with a sorbent based on transitional metal cyanoferrate, with the contact being realised in a medium of a suspension, which contains humic acid in an amount of 0.15-0.25 g/l relative to the volume of the processed solution or 0.15-0.25 g/dm2 relative to the surface of the processed object, with the ratio Ssorb:L not less than 0.001 kg/l.
EFFECT: possibility to increase the degree of purifying polluted objects of the radio-chemical industry from radionuclides and microelements.
The invention relates to the field of sorption technology of extraction of radionuclides and trace elements in the processing of various liquid and solid objects radiochemical industries.
The known method of extraction of radionuclides from aqueous solutions in a dynamic mode using inorganic composite sorbent containing non-magnetic fraction product processing metallurgical slag having the following composition: calcium silicate Ca2SiO4; iron oxide-lithium Li0,28Fe21/34O32; coasit SiO2; glandular grossular Ca3Al1,332Fe0,668Si3O12; ringwoodite Fe2SiO4; a sodium aluminum silicate of Na14,88Al15,26Si32,74O96; wherein the process is carried out at an initial pH value of not less than 2 and the final pH value of not more than 14 (patent RU 2330340, IPC G21F 9/12, 2008).
The disadvantages of this method are not sufficiently high degree of purification from radionuclides waste water solutions radiochemical production, and not a wide range of sorbed elements.
The known method of purification from radionuclides of water environment technology at nuclear facilities by filtering water through granular load ferrosilicomanganese sorbent containing 0.2 to 2 wt.% hydrazine; 35-48 wt.% water and 20-35 wt.% ferrocyanides composition Me(I) 4-2x[NixFe(CN)6where Me(I)-Li+, Na+, K+NH4+or their mixture; the rest is zirconium hydroxide (patent RU 2399974, IPC G21F 9/12, 2010) (prototype).
The disadvantages of the known method include the possibility of its application only to clean the radionuclides of cesium, as well as insufficiently high degree of purification (1,9·104-5,8·105).
Thus, the authors task was to develop a method of extraction of radionuclides and trace elements from both liquid and solid objects radiochemical industries, providing a wide range of items retrieved, along with a high degree of extraction.
The task is solved in the method of extraction of radionuclides and trace elements, including contacting the sorbent on the basis of cyanoferrate transition metal, in which the contacting is carried out in the environment of a suspension containing humic acid in the amount of 0.15-0.25 g/l in relation to the volume of the treated solution or 0.15-0.25 g/DM2in relation to the surface of the object to be processed, at a ratio of TSorb:Not less than 0.001 kg/L.
At the present time of patent and technical literature is not a method of extraction of radionuclides and trace elements from contaminated solid and liquid objects radiochemical industries using Sorb�NTA in the medium of suspension, containing humic acid in the amount of 0.15-0.25 g/l, at a ratio of TSorb:Not less than 0.001 kg/L.
Conducted by the authors of the study has allowed to establish that the use of a suspension of powder cyanoferrate transition metal in a solution of humic acid leads to the simultaneous sorption extraction not only of cesium and strontium, but additionally a large number of ions other trace elements is often found in radioactive waste as a result of getting fission products and activation (Co, Mn, Fe, Zr, Nb, U, Th, Y, La, rare earth).
The proposed technical solution is discovered by the authors of the intensification of sorption specificity (affinity) of cyanoferrate transition metal cations to the s-, p-, d - and f-elements at the trace level under the action of humic acid. This is because in the presence of humic acid distribution coefficient Kd (mg/g) of these trace elements in relation to cyanoferrate transition metals increases by 1-3 order of magnitude due to the fact that trace elements are sorbed not in plain Aqua-ions, and in the form of complexes with humic acid. And herself humic acid is practically not retained on cyanoferrate transition metal. This is a feature of humic acids as a representative of natural organic INR�funkcionalnych connections: as a complexing agent for all ions of chemical elements in aqueous solutions, humic acid however is not suppressed (as the majority of known ligands), and enhances the sorption affinity complexes formed with cyanoferrate.
Experimentally, the authors found quantitative limits of the content of humic acids, providing an increase of the distribution coefficient. So, by reducing the content of humic acid is less than 0.15 g/l, the decrease of the distribution coefficient, due to the suppression of complexation of trace elements with humic acid and, as a consequence, the suppression of their sorption. With increasing humic acid content of more than 0.25 g/l and a decrease of the distribution coefficient due to the formation of strong complexes with micronutrients dimeric form of humic acid, which suppresses their sorption.
Fig.1 shows the dependence of the distribution coefficient (Kd) for sorption of trace elements Mg, Al, Si, Ca, Ti, V, Cr, Mn, Co, Ni, Sr, Zr, Cs, Ce, Nd, Th, and U from the sample of river water of Beloyarsk reservoir (Sverdlovsk region) powder of Prussian blue Fe4[Fe(CN)6]3with an average particle size of 200 μm depending on the concentration of humic acid in water (pH=7,6; 23°C; mass of sorbent - 0.20 g; volume of solution is 300 ml).
The proposed method can be implemented as follows. Prepare a suspension by adding in �Astor humic acid at a concentration of 0.15-0.25 g/l in relation to the volume of the treated solution or 0.15-0.25 g/DM 2in relation to the surface of the object to be processed cyanoferrate transition metal in an amount that provides a ratio of TSorb:Not less than 0.001 kg/L. Then brought into contact with the object being processed: pour the treated solution or brought into contact with the surface of the object. The proposed technical solution can be implemented in a confined space (static sorption in the reactor) or in a flow system (dynamics of sorption in the filtration column). In the first case, in the reactor with the purified solution was added a suspension of the proposed composition, after mixing, provide exposure to sediment deposition, the purified solution with residues of humic acid is drained for further processing or discharge to the soil or river system. The precipitate, concentrate the target radionuclides and trace elements sent for drying and conditioning for subsequent burial.
In the second case in the pipeline with a clearing solution serves a suspension containing humic acid and cyanoferrate transition metal. The solution, stir the slurry is fed to the input column with filter powder from the same cyanoferrate transition metal. As a result of passing through the filter the filtrate solution with residues of humic acid is drained for further processing or discharge to p�CWU or river system. The precipitate from the filter column sent for drying and conditioning for subsequent burial.
The proposed method can be used for desorption of radionuclides and trace elements from the surface of solid objects, for example, from the walls of the reactor. In this case, the surface brought into contact with a suspension containing humic acid and cyanoferrate transition metal. After surface treatment, the suspension was decanted and passed through a column with filter bottom. The filtrate residues of humic acid is drained for further processing, discharge to soil or river system. The precipitate, concentrate the target radionuclides and trace elements sent for drying and conditioning for subsequent burial.
The proposed method relates to green chemistry because humic acids are natural-compatible chemicals, capable of plugging into the natural biochemical reactions in soils and hydrological systems. That is why the filtrates with residues of humic acid can be moved directly into the environment, for example, be poured into the ground or river water.
The proposed method is illustrated by the following examples.
Example 1. Take a sample of river water volume of 300 ml To control the content of cesium ions injected into the water sample additionally p�the target cesium chloride in a quantity to the initial concentration of cesium was 0,83 g/L. Then prepare the slurry using a 45 ml solution of humic acid selected from an underground well # 36 - re Salekhard, Tyumen region, containing humic acid 0,99 g/l Dilution of this volume in the sample corresponds to the concentration of 0.15 g/l humic acid when adding solution to the sample of river water. To a solution of humic acid is added 0.20 g of cyanoferrate (II) iron (III), which corresponds to the ratio of TSorb:L=4,4:1 (kg/l). The suspension is added to the sample of river water and can stand up to the establishment of empirical equilibrium at 22°C. the Separated precipitate and the solution filtered through a filter of "blue ribbon". After separation of the precipitate from the solution determine the concentration of cesium and other elements in the sediment composition analysis of the separated solution by the method of mass spectroscopy with inductively coupled plasma instrument Elan 9000 (Perkin Elmer) in a quantitative mode. According to the measurement results calculate the distribution coefficient Kd (mg/g) characterizing the affinity of the sorbent for cesium ions and other elements by the formula (1):
where Coand C are the initial and equilibrium (after adsorption) concentrations of trace elements in solution; V - 300 ml, m - 0,200 g.
Example 2. Take a sample of river water volume of 300 ml To control the content of cesium ions injected into PR�BU water is additionally a solution of cesium chloride in a quantity to the initial concentration of cesium was 0,83 g/L. Then prepare a suspension using 75 ml of a solution of humic acid selected from an underground well # 36 - re Salekhard, Tyumen region, containing humic acid 0,99 g/l. Enter this amount humic acids in a river water sample, which corresponds to a concentration of 0.25 g/l humic acid when adding solution to the sample of river water. To a solution of humic acid is added 0.20 g of cyanoferrate (II) iron (III), which corresponds to the ratio of TSorb:W=2,7:1 (kg/l). The suspension is added to the sample of river water and can stand up to the establishment of empirical equilibrium at 22°C. the Separated precipitate and the solution filtered through a filter of "blue ribbon". After separation of the precipitate from the solution determine the concentration of cesium and other elements in the sludge by the method of mass spectroscopy with inductively coupled plasma instrument Elan 9000 (Perkin Elmer) in a quantitative mode. According to the measurement results calculate the distribution coefficient (Kd(mg/g) characterizing the affinity of the sorbent for cesium ions and other elements by the formula (1):
where Coand C are the initial and equilibrium (after adsorption) concentrations of trace elements in solution; V - 300 ml, m - 0,200 g.
The table shows the comparative distribution coefficients (Kdobtained when using� of the proposed method and the prototype method.
|Kd (the proposed method)||Kd (method - prototype)||Kd (the proposed method)|
|Kd(prototype) Rel. EDN.|
Thus, the proposed method allows to significantly increase the degree of purification from radionuclides and trace elements contaminated sites radiochemical industry.
Method of extraction of radionuclides and trace elements, including contacting the sorbent on the basis of cyanoferrate transition metal, characterized in that the contacting is carried out in the environment of a suspension containing humic acid in the amount of 0.15-0.25 g/l in relation to the volume of the treated solution or 0.15-0.25 g/DM2in relation to the surface of the object to be processed, at a ratio of TSorb:Not less than 0.001 kg/L.
SUBSTANCE: invention refers to marine radioecology and biogeochemistry facilities. A method for determining the thorium-234 concentration in seawater bottom deposits consists in the fact that a radiochemical yield tracer is natural long half-life α-emitting isotope 232Th, initial activity of which is determined in the sub-sample with lead γ-emission -212 if the radioactive Th and Pb balance conditions are satisfied; another sub-sample taken by separating thorium from the respective elements by oxalate deposition, is used for liquid-scintiallation (LS) spectrometric analysis of 234Th and 232Th activities as shown by β- and α-emission; that is followed by calculating thorium radiochemical yield (R) and throrium-234 initial concentration (234Thyield, Bq/kg) by presented formulas.
EFFECT: invention provides more effective and reliable determination of the 234Th content.
SUBSTANCE: invention refers to radiation ecology and biogeochemistry, and aims at Th concentrating from seawater and determining its concentration. The method for thorium-234 concentration in seawater is implemented in series connected absorbers containing manganese dioxide that is followed by direct radiometric measurements of absorbed 234Th as shown by its primary β-emission. Each absorber works in the radially accurate regimen, which is generated by placing the disk absorber between diaphragms. The analysed water sample is supplied into the central portion of the absorber by means of a diaphragm with a central opening, then migrates to the periphery of the sorbed surface with using the diaphragm with peripheral openings.
EFFECT: varying the sedimentation process rate in the marine reservoirs.
SUBSTANCE: claimed invention relates to system for purification of wastes flow, mainly liquid or water radioactive wastes, for their safe utilisation and converting them into one or two forms, including water form for safe discharge into the environment and hardening form for safe utilisation. Realisation of claimed invention includes realisation of five steps, designated as I-V. Synchronisation of selection of sorbent substances and multirecycle option for separation of target substances from wastes flow is included as stage of step II (sorption and isotopic recovery by means of powder sorbent). Other steps correlate with sorption step (II), including oxidation (I) to deactivate or destruct existing chelating agents, solid-liquid separation (III) and selective ion exchange (IV) to achieve final desirable result of wastes flow processing. Final step consists in final processing (V).
EFFECT: possibility of obtaining predetermined specific strategy for target element by means of synchronisation of selection of sorbent substances ad multicycle option for removal of target substances from flow of radioactive wastes.
28 cl, 1 dwg
SUBSTANCE: invention relates to field of recycling of radioactive solutions. Composition of extraction chromatographic material for selective separation of U(VI), Th(IV), Np(IV) and Pu(IV) from nitric acid solutions contains three components. As complexants composition contains 33% of methyltrioctylammonium nitrate (MTOAN) and 1-16% of phosphoryl podand. As matrix composition contains macroporous spherical granulated copolymer of styrene with divinylbenzene. As phosphoryl podand used are derivatives of 1,5-bis[2-(oxyethoxyphosphoryl)-4-(alkyl)phenoxy-3-oxapentane of general formula I , where Alk is alkyl C1-C12.
EFFECT: extension of spectrum of highly efficient selective sorbents for extraction of U(VI), Th(IV), Np(IV) and Pu(IV) from nitric acid solutions.
SUBSTANCE: invention relates to radio analytical chemistry and can be used to monitor content of radionuclides in fresh and sea water, in urine of individuals exposed to radiation and in samples of different process solutions. The method of extracting radionuclides from aqueous solutions includes filtering the solution through a selective sorbent placed in the drip chamber of an apparatus used for intravenous transfusion of infusion solutions and preparing an agent suitable for gamma-ray spectrometry.
EFFECT: faster method while maintaining high efficiency and reducing measurement errors and distortion of results due to absorption of the measured gamma-radiation by filters.
2 cl, 3 dwg
SUBSTANCE: invention relates to sorption extraction of caesium radionuclides from aqueous solutions. The method of extracting caesium radionuclides includes filtering an aqueous solution through a selective sorbent which is iron-potassium ferrocyanide on a support, desorption of caesium from the sorbent with an alkaline solution containing Trilon B and potassium oxalate. The eluate obtained from desorption is further filtered through a sorbent which is nickel-potassium ferrocyanide.
EFFECT: faster caesium extraction and minimal volume of obtained concentrate containing caesium radionuclides.
1 tbl, 2 ex
SUBSTANCE: invention relates to sorbents produced on the basis of fly grit microspheres of thermal electric power stations and can be used for removal of radio nuclides from liquid wastes. Synthesis of sorbent comprises deposition of active component on the surface of microspheres by mixing the latter with alkaline metal ferrocyanide solution (arrester), removal of excess arrester solution whereby arrester volume retained by microspheres is defined. Transition metal salt solution is added to the mix of microspheres and arrester to hold the mix to phase separation. Thereafter liquid phase is removed while obtained sorbent is dried. In compliance with second version, sorbent synthesis comprises processing of microspheres with the solution of vanadium, or zirconium or tungsten salts and removal of excess solution whereby salt solution volume retained by microspheres is defined. Thereafter, alkaline metal ferrocyanide solution (arrester) is added thereto, excess arrester solution is removed to hold the mix to phase separation. Thereafter liquid phase is removed while obtained sorbent is dried. In compliance with both versions, sorbent is dried at 60-80°C for 1-2 hours or at a room temperature for 15-20 hours.
EFFECT: efficient removal of cesium, cobalt, cerium, europium, etc.
11 cl, 6 dwg, 6 ex, 1 tbl
SUBSTANCE: invention relates to safe operation of nuclear power plants. Content of uranium in process media of nuclear power plants is controlled as follows: collecting a sample of the process medium, alkanising said sample to pH 9-11 by adding ammonia, filtering through a cellulose acetate membrane with freshly deposited manganese dioxide, dissolving the membrane with manganese dioxide in hydrochloric acid while boiling, reducing uranium with ascorbic acid and zinc metal to oxidation state IV, and then determining content of uranium in the solution using a photometric method using arsenazo III in a chloride medium.
EFFECT: simple and faster control, lowering the uranium detection limit 40-fold.
SUBSTANCE: radionuclides and toxic metal ions are removed from water using sorbents in form of gaize crumbs with diameter of 20-50 mm.
EFFECT: invention enables to avoid intermediate operations and use of deactivating substances.
FIELD: power engineering.
SUBSTANCE: method to decontaminate liquid wastes containing one or several radioactive chemical elements to be removed, including the following stages: the stage of putting in contact the liquid wastes with the solid particles in the first reactor; the stage of suspension settling in the second reactor, as a result of which the solid phase is produced, and the liquid phase; the stage of separation of the specified solid phase and the specified liquid phase, a part of the specified solid phase produced after the stage of settling is repeatedly sent into the first reactor for realisation of the stage of putting in contact.
EFFECT: invention makes it possible to improve efficiency of decontamination.
6 cl, 1 dwg
FIELD: recovery of liquid radioactive wastes.
SUBSTANCE: proposed method includes bringing liquid radioactive wastes in contact with matrix saturated with selective ion-exchange material (solid extracting agent). Glass-crystal material with open porous structure is used as matrix for the purpose. Matrix material is produced from hollow glass-crystal cene spheres formed from mineral particles of volatile ash produced as result of black coal combustion and saturated with selective ion-exchange material.
EFFECT: facilitated procedure of radionuclide extraction.
5 cl, 1 tbl, 5 ex
FIELD: recovery of liquid radioactive wastes.
SUBSTANCE: proposed method includes treatment of radioactive wastes by heavy-metal ferrocyanide and separation of sediment obtained. In the process liquid radioactive wastes are treated with heavy-metal ferrocyanide formed upon introduction of potassium ferrocyanide and bivalent nickel and/or copper and iron salts taken in amount abundant with respect to stoichiometric quantity. Clarified solution is treated with oxidant upon separation of sediment and filtered through catalytic material containing manganese dioxide. Then filtered-off solution is passed through highly acid cationite in Na-form and highly basic anionite in Cl-form.
EFFECT: enhanced decontamination quality.
5 cl, 1 tbl, 7 ex
FIELD: reactive sorbents.
SUBSTANCE: liquid is conditioned at pH 4-6 and then is brought into contact with chelating ion-exchange resin composed of grafted polyazocycloalkanes at temperature above or equal to 60°C.
EFFECT: enhanced metal removal efficiency.
35 ex, 9 dwg, 9 tbl, 5 ex
FIELD: processing of liquid radioactive wastes.
SUBSTANCE: the proposed method for cleaning of liquid radioactive wastes includes their processing with absorber-sorbent. Ash wastes are used as the absorber-sorbent. The ash wastes are introduced into liquid radioactive wastes in the stage of their neutralization at pH = 0.5-2 at the flow rate, ensuring the ratio of S : L = 1 : (15-50). Then the obtained suspension is separated into the liquid and solid phases.
EFFECT: increased degree of cleaning from radionuclides and enhanced separation rate of produced pulps.
4 cl, 1 tbl, 11 ex
SUBSTANCE: invention relates to application of pectin solution as detergent for skin and hair in radioactive and environmentally hazardous regions. Pectin containing in solution due to chelating action bonds to heavy metal ions to form stable compounds (micelles) having very large size and prevents transferring thereof trough transdermal barrier. Formed micells may be easily removed from human body.
EFFECT: new detergent for skin and hair useful in radioactive and environmentally hazardous regions.
2 ex, 5 tbl
FIELD: methods of the sorption decontamination of waters from the radioactive impurities.
SUBSTANCE: the invention is pertaining to the method of the sorption decontamination of waters from the radioactive impurities. The method of decontamination of the water from radiostrontium includes the treatment of the water with a sorbent based on the burned bauxite ore. At that the ore is burned together with calcium -magnesium lime - CaCO3·MgCO3 and sodium soda salt - Na2CO3 at the temperature of no less than 1200°C and flushed with the water to remove the solvable sodium compounds. It is preferable, that the mixture of the bauxite ore is subjected to burning with calcium-magnesium lime and sodium soda salt in the mass ratio of 1 : 0.55-0.60 : 0.055-0.060. The method ensures an increased effectiveness of removal of the radiostrontium at usage of the initial bauxite ore without lowering of effectiveness of the water decontamination from radiocesium, and also allows to reduce considerably the amount of the spent sorbents, which are subjected to disposal.
EFFECT: the invention ensures an increased effectiveness of removal of radiostrontium from the water at usage of the initial bauxite ore without lowering of effectiveness of the water decontamination from radiocesium, allows to reduce considerably the amount of the spent sorbents, which are subjected to disposal.
2 cl, 10 ex
FIELD: environment control including environment protection in atomic industry.
SUBSTANCE: proposed method for decontaminating radioactive aqueous solutions from radionuclides includes at least one contact of solution with complexing sorbent that has solid-medium immobilized active polymeric layer condensed with chelates. Medium is chosen from following group: activated cellulose; synthetic copolymers with divinyl benzene, activated chloromethyl or hydroxymethyl, or chlorosulfonic groups. Active sorbing layer has ethylenediamine or diethylene tridiamine, or tetraethylene pentaamine, or polyethylene polyamine with copolymers; chelates are chosen from group incorporating carboxyl-containing chelates, phosphonic-group chelates, and hydroxyl-containing chelates. Proposed method enables extraction of radionuclides both in ionic and colloidal condition from solutions doped with highly concentrated impurities; sorbent used for the purpose retains its sorbing properties upon repeated regenerations and is capable of decontaminating solutions both in dynamic and static modes with different pH of solutions being decontaminated.
EFFECT: enlarged functional capabilities.
11 cl, 3 tbl
FIELD: technology of handling of the liquid nuclear wastes of the nuclear fuel and power cycle; methods of reprocessing of the liquid nuclear wastes.
SUBSTANCE: the invention is pertaining to the procedure of the liquid nuclear wastes handling of the nuclear fuel and power cycle and may be used during reprocessing of the liquid nuclear wastes (LNW). The method includes the preliminary concentration, ozonization, microfiltration of the vat residue with fractionation of the permeate and the concentrate and the ion-selective purification of the permeate using the ion-selective a sorbent. At that the microfiltration is conducted at least in two stages: the permeate of each previous stage of the microfiltration is directed to the microfiltration as the source solution for the subsequent stage of the microfiltration, and at the final stage of the permeate from the microfiltration is sent to the utilization. The concentrate produced at each next stage of the microfiltration is mixed with the source solution of the previous stage of the microfiltration. The concentrate produced at the first stage of the microfiltration is directed to the conditioning and dumping. The ion-selective sorbent is added in the permeate of the previous stage of the microfiltration before the final stage of the microfiltration. The invention ensures: reduction of the volume of the liquid nuclear wastes due to the deep purification of the LNW with the high saline share from the radionuclides and extraction of the radionuclides in the compact form of the sparingly soluble compounds at the corresponding increase of the factor of purification of the salts extracted at the stage of the vat residue treatment; reduction and optimization of the consumption of the permeate and concentrate interacting with the source solution as well as produced at the further stages.
EFFECT: the invention ensures: reduction of the volume of the liquid nuclear wastes; the deep purification of the LNW with the high saline share from the radionuclides and extraction of the radionuclides in the compact form of the sparingly soluble compounds at the corresponding increase of the factor of purification of the salts extracted at the stage of the vat resudue treatment; reduction and optimization of the consumption of the permeate and concentrate interacting with the source solution ands produced at the further stages.
FIELD: nuclear-industry radiochemical enterprises for recovering and immobilizing gaseous radioactive wastes.
SUBSTANCE: sorbent used for entrapping radioactive iodine from gas-aerosol stream running from irradiated nuclear fuel cutting-and-dissolving unit has porous base impregnated with nitric acid silver salt (AgNO3); used as sorbent base is porous silicon carbide of 30 to 60% porosity.
EFFECT: enhanced corrosion and mechanical resistance of material in chemically active media.
1 cl, 2 dwg, 3 tbl
FIELD: environmental protection.
SUBSTANCE: invention relates to means and methods of integrated degassing, disinfection, and shielding of sites and zones, where presence of high-activity poisonous substances, poison-gases, chemical weapons, pathogenic microorganisms, their vital activity toxic products, insects (including carriers of human and animal diseases), radioactive substances are revealed or suspected, and also to means and methods to extinguish burning of inflammable liquids and to prevent in inflammation of spills of inflammable liquids. Multifunctional foam composition of invention includes, as active substance, 0.1-5% of didecyldimethylammonium halide clatrate with urea. Use of indicated clatrate provides simultaneous effect of foam compositions, wherein clatrate acts both as multifunctional active substance and as foaming agent. Invention can further be used to eliminate consequences of use of weapons of mass destruction and to eliminate consequences of man-made accidents and emergency situations.
EFFECT: expanded protection possibilities.
24 cl, 3 tbl, 6 ex