The method of extraction of the radionuclide strontium from aqueous solutions (options)

 

(57) Abstract:

Usage: the invention relates to sorption methods of cleaning solutions from radioactive strontium and can be used for extraction of the radionuclides of strontium from solutions with high content of hardness salts and liquid radioactive waste complex chemical composition. The inventive method consists in the joint processes of sorption and coprecipitation of strontium on the sorption-reagent materials (SRM). CPM is formed directly in the cleaning process in the interaction of initial sorption-reagent material containing the exchange cations of barium, with the purified solution containing sulfate ions. This interaction leads to the formation of insoluble barium sulfate in the matrix sorption-reagent materials. As CPM use amorphous barium silicate or amorphous barium titanate, or amorphous barium lead zirconate. The content of barium in the matrix of these materials is respectively in g/g of material: 0,005-0,250; 0,005-0,300; 0,005-0,200. Used in the method of the sorption-reagent materials have a pore volume from 0.50 to 0,400 cm3/g of material and effective pore radii from 2 to 30 nm. The end of: providing a high coefficient of cleaning vysokozolnyh solutions from radionuclide strontium at the expense of achieving high selectivity strontium-calcium and reduce the influence of organic matter on the recovery of strontium. 3 S. and 9 C.p. f-crystals, 2 tab., 4 Il.

The invention relates to sorption methods of cleaning solutions from radioactive strontium and can be used to extract radioactive strontium from solutions with high content of hardness salts and liquid radioactive waste (LRW) complex chemical composition.

The use of sorption processes for the extraction of radioactive strontium from solutions is quite a technological point of view the possibility of reducing the volume of radioactive wastes long-term disposal, and improve the reliability of their storage.

However, sorption technology LRW purification are characterized by a significant drawback is the strong dependence of the efficiency of extraction of radionuclides from the chemical composition of the solutions. This dependence is due mainly to insufficient selectivity of the used sorbents for specific radionuclides. This fully applies to the strontium-90, one of the most important long-lived radionuclides.

Known purification method kaboolian solutions type sea water from strontium and other radionuclides (U.S. Pat. RF 2101234, publ. 10.01.98 year), including contacted the or Nickel, the subsequent introduction of a chemical reagent, precipitating the sulfate ions, which is used as the barium chloride, separation of radioactive sludge and storage. The molar ratio of barium and sulphate ions is (1,0-1,1):1,0. In the method using inorganic sorbent on the basis of the ferrocyanides of copper or Nickel and a porous inorganic carrier grade NGA or MJA-M

However, implementing this method, it is difficult to obtain high efficiencies from radionuclides of strontium, as the cleaning efficiency in a fixed bed of sorbent is much higher than the sorption and coprecipitation in containers, as well as to achieve a high relationship cleaned LRW to the resulting TRO due to the large amount of precipitate of barium sulfate and a low selectivity coprecipitation of strontium to barium sulphate. In addition, the described method requires a large amount of technological equipment than the conventional method of purification by filtration through selective sorbent, because in addition to the sorption unit requires additional technological capacity for cleaning solutions by coprecipitation.

Known to date, the most selective sorbents based silicotitanate (type IE-911, UOP, USA) and Dix is only in the case of low content of hardness salts and the absence of complexing agents (J. Lehto, R. Harjula Selective Separation of Radionuclides from Nuclear Waste Solutions with Inorganic Ion Changers. Radiochim. Acta v.86, pp.65-70, 1999).

Closest to the claimed method is sorption of strontium-90 from natural non-saline water, which can be attributed to the so-called sorption-reagent methods (Ryjenkov A. P., Egorov Y. C. Sorption of strontium-90 from freshwater in the process of sulfate modification of barium manganite. Radiochemistry, 1995, T. 37, vol.6, S. 549-553). Used in the method of the sorption-reagent material (SRM) is a thin layer of inorganic sorbent is printed on wood-pulp granular media manganite barium content barium 0,120-0,180 g/g of sorbent. According to this method the water to be treated is optionally injected reagents containing sulfate anions that interact with cations of barium sorption-reagent material with the formation of insoluble barium sulfate. This interaction sorption-reagent material with the components of the solution containing the extracted substance, leads to a considerable improvement in the efficiency of extraction of strontium due to additional adsorption and coprecipitation on a new sulfate sorption phase. Optimal Echaskech conditions.

The disadvantages of the method are its low efficiency for cleaning solutions with high salt content rigidity for reasons of low selectivity in the system of the strontium-calcium and sensitivity of the sorbent to the content of organic substances due to the recovery of manganites barium.

The objective of the invention is to provide a high coefficient of cleaning vysokozolnyh solutions from radionuclide strontium at the expense of achieving high values of selectivity coefficients strontium-calcium and reduce the influence of organic matter on the recovery of strontium.

The problem is solved by the proposed sorption-reagent method of extraction of the radionuclide strontium from aqueous solutions implemented in three versions.

The method of extraction of the radionuclide strontium from aqueous solutions sorption-reagent method according to the first embodiment is to combine the processes of sorption and coprecipitation of strontium on the sorption-reagent materials obtained directly in the cleaning process in the interaction of initial sorption-reagent material containing the exchange cations of barium, with the purified solution containing sulfate ions, resorbtion-reagent material is an amorphous barium silicate, and the content of barium in the matrix material is 0.005 to 0.250 g/g of material.

The method of extraction of the radionuclide strontium from aqueous solutions sorption-reagent method according to the second variant is to combine the processes of sorption and coprecipitation of strontium on the sorption-reagent materials obtained directly in the cleaning process in the interaction of initial sorption-reagent material containing the exchange cations of barium, with the purified solution containing sulfate ions, resulting in the matrix sorption-reagent material insoluble barium sulphate, while the sorption-reagent material is an amorphous barium titanate, and the content of barium in the matrix material is 0.005 to 0,300 g/g of material.

The method of extraction of the radionuclide strontium from aqueous solutions sorption-reagent method according to the third variant is to combine the processes of sorption and coprecipitation of strontium on the sorption-reagent materials obtained directly in the cleaning process in the interaction of initial sorption-reagent material containing the exchange cations of barium, with the purified insoluble barium sulphate, thus the sorption-reagent material is an amorphous lead zirconate, barium, and the content of barium in the matrix material is 0.005 to 0,200 g/g of material.

The concentration of sulfate ions in the solution in the process in all cases is not less than 310-3M/DM3.

Proposed to be used for extraction of the radionuclides of strontium from aqueous solutions of the initial sorption-reagent materials based on silicate, titanate or lead zirconate, barium have a pore volume from 0.050 to 0,400 cm3/g of material and effective pore radii from 2 to 30 nm.

When the content of barium sorption-reagent materials less than 0.005 g/g material the effect of increasing the selectivity of the reaction with barium sulphate is poorly defined.

When the content of barium sorption-reagent materials (g/g material) above 0.25 for barium silicate, 0.3 for barium titanate and 0.2 for barium lead zirconate derived sorbents have insufficient mechanical strength for use in the technique.

When the pore radius is less than 2 nm, the formation of barium sulfate in porous space of a matrix is difficult, the precipitate of barium sulphate is formed in solution and, therefore, eliminates the effect aespecially synthesis conditions.

When the volume of pores below 0.050 cm3/g material effect formation of barium sulfate in the matrix material is too small, when the pore volume of more than 0,400 cm3/g strength of materials - low.

In General, the method of purification of aqueous solutions containing the radionuclide strontium in the presence of significant (1-30 mg-EQ/DM3) amounts of calcium ions, as follows. If cleared, the solutions do not contain necessary for implementing the method of the amount of sulfate ions, they add sodium sulfate, in an amount to provide a total content of sulfate ions in the solution is not less than 310-3M/DM3. Further, the process can be conducted in various ways: (a) to the resulting solution was added source sorption-reagent material in an amount to provide the desired degree of cleaning solution from the radionuclide strontium; (determined experimentally); b) the resulting solution is passed through a bulk filter loaded sorption-reagent material with a bulk velocity 1-50 column volumes/hour depending on the desired degree of purity (determined experimentally). The dependence of the partition coefficients (Kdfrom the concentration of sulfate ions until otrastaet two orders of magnitude.

This process is achieved selectivity coefficients strontium-calcium not less than 10, which allows to obtain partition coefficients of strontium in solutions with a high content of hardness salts (like sea water) not less than 5 000. The process of extraction of strontium in contrast to the extraction of strontium to barium manganite by a known method practically does not depend on the presence of reductants in solution in the absence of the proposed CPM-ion oxidants.

The observed increase in selectivity is related with the formation of a fine precipitate of barium sulfate in the matrix of sorbent particle size which is determined by the porous structure of the matrix, and by selective for strontium exchange places in the matrix of sorbent released by the reaction of barium cations with sulfate ions. The volume of pores in the proposed sorption materials on average 10 times greater than that of barium manganite.

Proof of education in the matrix sorption-reagent materials precipitation of barium sulfate can serve as the data of x-ray phase analysis, shown in Fig. 2, from which it is clear that after sorption of strontium sulfate solution on the radiograph appear re aristoi the system matrix of the sorbent is confirmed by the study of specific surface area (a) original CPM (before reaction with sulfates) and (b) CPM after reaction with sulfates, showed a significant increase in the specified index CPM after sorption of strontium and education of barium sulfate in a phase SRM (table.1).

The proposed method allows you to clean almost any type of LRW, for example sea water, evaporating brines and brine resulting from the application of reverse osmosis treatment methods waste.

The use of the proposed method of cleaning solutions from radioactive strontium suitable for fluids with a salt content of more than 1 g/l, total hardness above 5 mEq/L. empirically shown that the method is also effective for cleaning vysokozolnyh LRW salt hardness above 100 mEq/L. When the salt content below 50 mg/l, the cost of the sorption-reagent purification method is higher than methods such as ion exchange and reverse osmosis.

The possibility of carrying out the invention the following examples.

EXAMPLE 1. Liquid radioactive waste containing sea water (concentration of calcium ions is 0.5 g/l of magnesium ions, 1.2 g/l, sulfate ions and 2.4 g/l, the specific activity of the radionuclide strontium - 1,210-6CI/l is passed through a column of barium silicate with a diameter of 10 mm layer height with the major clean-up of these solutions is known sorbents IE-911 and DMT.

EXAMPLE 2. In liquid radioactive waste (water decontamination) containing calcium ions is 0.1 g/l, oxalic acid, 0.05 g/l of the surfactant is 0.01 g/l, the volumetric activity of radionuclides strontium - 3,710-7CI/l, add sodium sulfate to a concentration of 0.7 g/L. the resulting solution was passed through a column of barium titanate with a diameter of 10 mm in height with a layer of sorbent 150 mm Clearance from radionuclides strontium shown in the drawing (Fig.4).

EXAMPLE 3. Carried out analogously to example 1, except that the sorption-reagent material used barium lead zirconate. The cleaning results are shown in the drawing (Fig.4).

Comparative data on the distribution coefficients of strontium (Kd) and the selectivity coefficients strontium-calcium (Ks) during sorption of strontium from sea water for the proposed method and by use of the known sorbents are given in table. 2.

As follows from experimental data table. 2, the efficiency of the sorption-reagent materials based on barium silicate, barium titanate and lead zirconate, barium ten times higher than in the case of other known selective for strontium, sorbents.

1. How to retrieve radionucl saw sorption and coprecipitation of strontium on the sorption-reagent materials, obtained directly in the cleaning process in the interaction of initial sorption-reagent material containing the exchange cations of barium, with the purified solution containing sulfate ions, leading to the formation of insoluble barium sulfate in the matrix sorption-reagent material, wherein the sorption-reagent material is an amorphous silicate of barium, and the content of barium in the matrix material is 0.005 to 0.250 g per gram of material.

2. The method according to p. 1, characterized in that the sorption-reagent material has a pore volume from 0.050 to 0,400 cm3/g of material.

3. The method according to p. 1, characterized in that the sorption-reagent material has an effective pore radii from 2 to 30 nm.

4. The method according to p. 1, characterized in that the concentration of sulfate ions in the solution is not less than 310-3M/DM3.

5. The method of extraction of the radionuclide strontium from aqueous solutions sorption-reagent method consisting in the joint processes of sorption and coprecipitation of strontium on the sorption-reagent materials obtained directly in the cleaning process in the interaction of initial sorption-ribadedeva to the formation of insoluble barium sulfate in the matrix sorption-reagent material, characterized in that the sorption-reagent material is an amorphous barium titanate, and the content of barium in the matrix material is 0.005 to 0,300 g per gram of material.

6. The method according to p. 5, characterized in that the sorption-reagent material has a pore volume from 0.50 to 0,400 cm3/g of material.

7. The method according to p. 5, characterized in that the sorption-reagent material has an effective pore radii from 2 to 30 nm.

8. The method according to p. 5, characterized in that the concentration of sulfate ions in the solution is not less than 310-3M/DM3.

9. The method of extraction of the radionuclide strontium from aqueous solutions sorption-reagent method consisting in the joint processes of sorption and coprecipitation of strontium on the sorption-reagent materials obtained directly in the cleaning process in the interaction of initial sorption-reagent material containing the exchange cations of barium, with the purified solution containing sulfate ions, with the formation of insoluble barium sulfate in the matrix sorption-reagent material, wherein the sorption-reagent material is an amorphous lead zirconate, barium, and soderzhaniya fact, what sorption-reagent material has a pore volume from 0.050 to 0,400 cm3/g of material.

11. The method according to p. 9, characterized in that the sorption-reagent material has an effective pore radii from 2 to 30 nm.

12. The method according to p. 9, characterized in that the concentration of sulfate ions in the solution is not less than 310-3M/DM3.

 

Same patents:

The invention relates to the chemical treatment technology solutions from radioactive elements

The invention relates to the treatment of aqueous media from radioactive contaminants by sorption and can be used in the process of operation of energy transport facilities

The invention relates to the purification of the environment, namely to extract radioactive isotopes from contaminated soil

The invention relates to radiochemistry, namely, the purification of liquid radioactive waste

The invention relates to nuclear technology, namely, to remove from the circuit of a nuclear reactor of potentially hazardous substances

The invention relates to the production of sorbents from lignocellulosic plant raw material, which can be used for cleaning liquid media (cross water, oil, agricultural products, particularly milk), land reclamation and agricultural land contaminated with radionuclides

The invention relates to the technology of disposal of liquid radioactive waste (LRW) membrane-sorption methods

The invention relates to materials for wastewater treatment of nuclear and radiochemical industry, as well as the natural aquatic environment from radioactive isotopes

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

FIELD: medicine.

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

Up!