RU2553976C1 - Method of removing 60co from process solutions of radiochemical plants relating to medium- and low-activity wastes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of removing ⁶⁰Co from process solutions of radiochemical plants, relating to medium- and low-activity wastes, is carried out via preliminary heterogeneous catalytic decomposition of organic components contained in the process solutions (liquid radioactive wastes) of radiochemical plants, on a solid-phase catalyst followed by extraction of ⁶⁰Co from the solutions via coprecipitation thereof with residues of complex cyanides and hydroxides of transition metals (Co, Ni, Zn) and final ion-exchange purification of the filtrate on a cationic-exchange resin (Lewatit MonoPlus TP 207 type).

EFFECT: low residual specific activity of solutions of medium- and low-activity wastes, which enables to change the category of the wastes into non-radioactive wastes.

14 cl, 1 dwg, 6 tbl, 3 ex

Description

The invention relates to radiochemical technology and can be used in the technology of processing liquid radioactive waste (LRW) of radiochemical production.

An important task in ensuring radiation safety during the operation of radiochemical plants is to solve the problem of cleaning and processing LRW generated during various technological operations with solutions containing radionuclides, as well as decontamination of equipment and operation of power plants. LRW also includes collections of floor drain systems and vacuum drainage of premises, decantation of settling apparatus, and liquid wastes from special laundries. With significant volumes of LRW formed, not only the cleaning factor (coefficient) is important, but also the residual levels of radionuclides in solutions after their processing, which determines the possibility of reusing water resources without using the stage of evaporation and processing of bottoms. As a rule, the main radionuclides to be purified include ¹³⁷ Cs, ⁶⁰ Co radionuclides. The methods used in the technology for ion-selective purification of ⁶⁰ Co involve preliminary oxidative treatment of solutions in order to destroy complexing agents and subsequent stages of the separation of radionuclides, for example, using inorganic sorbents and cation-exchange resins with a desalting effect. The methods used allow efficient purification of ¹³⁷ Cs with a purification factor of 10 ² -10 ⁴ . However, the purification factor from ⁶⁰ Co in this case, as a rule, does not exceed 10 ² , which does not allow reducing the activity of the solutions after processing to less than 10-50 Bq / l.

Since LRW technological solutions contain, as a rule, not only the components introduced into the solutions: aminopolycarboxylic acids; oxalic, citric, tartaric acids and their salts; sodium salts of ethylenediaminetetraacetic (EDTA) and diethylenetriaminepentaacetic (DTPA) acids, but also organic components of a variable composition, formed as a result of radiolysis during long-term storage of LRW and forming chelate complex compounds with high stability constants with ⁶⁰ Co, a prerequisite for increasing the clearance factor ⁶⁰ Co is the complete destruction (oxidation) of all organic components of LRW regardless of their composition.

Surfactants contained in solutions (surfactants of anionic, ampholytic, nonionic types), high molecular weight compounds, biocolloids also require both methods that intensify oxidative degradation, and the use of specialized methods for the destruction of a colloid, which contains ⁶⁰ Co.

Thus, the task of increasing the factor (coefficient) of purification of medium-active (CAO) and low-level (NAO) LRW from ⁶⁰ Co and achieving the necessary completeness of removal of ⁶⁰ Co can be solved comprehensively by sequentially catalytic oxidation of organic components of LRW and coagulation-precipitation with mixed ferrocyanides transition metals. The determining factor in this case is the completeness of the destruction of complexing and colloid-forming components of LRW of variable composition.

From the existing level of technology there is a known method for extracting ⁶⁰ Co radionuclide from liquid radioactive waste of nuclear power plants, which consists in introducing iron (III), nickel (II) cations in LRW (in a 1: 1 molar ratio) into contact with potassium ferrocyanide in a molar ratio of 2: 1 to 4: 1, holding the solution at room temperature and separating the precipitate by centrifugation [RU 2497213, G21F 9/12, publ. 10.27.2013], [Kulukhin S.A., Konovalova N.A., Gorbacheva M.P. and others // Radiochemistry. 2013. V. 55, N 3. S. 242-248]. The disadvantages of this method are: the lack of oxidation of organic components of LRW; the obligatory use of iron salts, which form difficult to filter dispersions of hydroxide nature in aqueous solutions. In the presence of surfactants in LRW at a concentration of> 200 μg / L, this method is ineffective and does not allow obtaining the declared purification factor from ⁶⁰ Co. The effectiveness of the method is shown only at a concentration of sodium ferrocyanide> 50 mmol / L, which leads to a significant consumption of reagents and the formation of a significant amount of precipitate, the completeness of separation of which is not indicated with the claimed centrifugation method. The presence in the solution after deposition of fine suspensions of less than 150 nm does not allow efficient separation of the precipitate. Solutions that have been cleaned from ⁶⁰ Co turn out to be contaminated as a result of processing with an excessive amount of introduced cations. The indicated method cannot be sufficiently effective, since it does not take into account the presence of microcomponents of an organic nature and the probability of finding ⁶⁰ Co in an ultramicroheterogeneous free-dispersed state in real LRW. Technological adaptation of this method requires the use of expensive equipment necessary to separate a significant amount of fine sediment - a cascade of filtering centrifuges with a separation factor of at least 15,000.

A known method of processing liquid radioactive waste from a nuclear power plant, which includes their preliminary evaporation to obtain condensate and bottoms, ozonation of bottoms, separation of the resulting radioactive sludge and concentration of the filtrate by deep evaporation. After separation of the radioactive sludge, the filtrate is passed through a filter container with a cesium selective inorganic sorbent, then the spent filter container is sent for storage or disposal [RU 2226726, G21F 9/00, publ. 04/10/2004]. The main disadvantages of this method are: the probability (with the introduction of ozone) of uncontrolled autocatalytic decomposition of a significant amount of organic components of LRW of variable composition with the risk of changing the temperature-pressure parameter in the apparatus; the absence of a specialized stage for the separation of ⁶⁰ Co from the solution after ozonation and, as a consequence, the insufficient completeness of the separation of ⁶⁰ Co, leading to the need to concentrate the filtrate by evaporation; high energy intensity of the process; increased consumption of reagents (ozone); the need to maintain a constant pH level; as well as increased requirements for fire and explosion safety measures during the process.

Closest to the claimed method is a method of purification of bottoms of liquid radioactive waste from radioactive cobalt and cesium by oxidation of bottoms and the release of activated corrosion products by filtration [RU 2467419, G21F 9/30, publ. 11/20/2012]. Vat residue is exposed to hard ultraviolet (UV) radiation and the process is conducted at a pH of 7-10 and a temperature of 45-98 ° C using hydrogen peroxide. After microfiltration separates the sludge containing radioactive cobalt, iron, manganese, solutions of alkali metal diethyl dithiocarbamates and transition metal salts are simultaneously introduced into the filtrate at the same pH and temperature values, followed by microfiltration of the resulting transition metal diethyl dithiocarbamate precipitate with radioactive cobalt, and radioactive cobalt ion-selective sorbents stepwise counterflow method with the removal of spent sorbents by microfiltration together with di cobalt ethyldithiocarbamate. The disadvantages of this method (prototype) are: low productivity and complexity of the technological organization of the oxidative treatment of LRW in dynamic mode, requiring a certain geometry of a flowing quartz cell (or from another expensive UV-permeable material) of small volume, constant flow rate; the complexity of the technological organization of the oxidative treatment of LRW in static mode due to the duration of the process (more than 6 hours), the decrease in the efficiency of using a UV lamp with a salt content> 10 g / l and increased turbidity and, as a result, insufficient completeness of the oxidative destruction of organic components of LRW; when alkali metal diethyl dithiocarbamate is introduced into the LRW solution with a pH of 7-10 at the same time as transition metal salts, the transition metal hydroxides are first formed, which reduces the efficiency of the use of diethyldithiocarbamate and requires a greater concentration in the solution. Moreover, the resulting effect in the specified method is due mainly to the coprecipitation of ⁶⁰ Co on transition metal hydroxide; the coprecipitation of ⁶⁰ Co, which is in solution in a colloidal state (in the presence of a residual amount of high molecular weight compounds and surfactants after oxidative treatment) with transition metal diethyldithiocarbamate, does not allow to obtain the claimed purity.

The objective of the invention is to develop a technologically suitable method that allows the purification of CAO and NAO from ⁶⁰ Co at the same time as purification from ¹³⁷ Cs to a level of residual specific activity sufficient to transfer LRW into the class of non-radioactive waste.

The technical result of the invention is to reduce the residual specific activity of solutions of CAO and NAO for ¹³⁷ Cs and ⁶⁰ Co to a level of <0.9 Bq / l, which allows you to change the class of waste to non-radioactive waste (solutions).

To achieve the specified technical result in the method of purification from ⁶⁰ Co of technological solutions of radiochemical production related to medium and low-level waste, the organic components contained in LRW are destroyed by catalytic oxidative thermal decomposition on a solid-phase catalyst in a dynamic mode in a continuous-type column type apparatus with the geometry of the bulk catalyst layer in the ratio "diameter / height" - 1:15, and the selection of ⁶⁰ Co from the solutions is carried out in three consecutive operations of coprecipitation of radionuclides with precipitates of mixed transition metal ferrocyanide (the concentration of transition metal nitrate in solution is 10 mmol / l, the molar ratio of transition metal nitrate and potassium ferrocyanide is 1.0: 1.9), transition metal hydroxide using a flocculant and separation of the precipitate on each deposition and final ion exchange purification of the filtrate on a cation exchange resin (type Lewatit MonoPlus TP 207), selective for transition metal ions.

In the particular case, aluminum-zirconium (ZrO ₂ —PdO / Al ₂ O ₃ ) is used as a solid-phase catalyst. To increase the specific surface area of the catalyst, a platinum catalyst is used, deposited on an VP-1AP anion-exchange resin with a weight content of platinum of 0.5-2%. Since platinum is an expensive metal, a nickel-ferricyanide catalyst supported on a VP-1AP anion-exchange resin with a nickel ferricyanide weight content of 5-7% is used as a cheaper catalyst.

In the particular case, for co-precipitation of ⁶⁰ Co radionuclides with a precipitate of mixed transition metal ferrocyanide, a cobalt salt is used as a transition metal salt. A lower cost nickel salt may be used. Zinc salt can also be used to obtain a smaller volume of sediment, which will speed up the filtration stage.

In the particular case, in order to reduce the amount (volume) of the catalyst used, the diameter / height ratio of the bulk catalyst layer in the catalyst column can be 1: 5.

In the particular case, for more efficient isolation of ⁶⁰ Co, sodium diethyldithiocarbamate (C _Na - _DEDC = 10-100 mg / L) can be used at the stage of co-precipitation of radionuclides with mixed transition metal ferrocyanides.

In the particular case, to reduce the cost of implementing the developed method, the concentration of transition metal nitrates added to the solution for coprecipitation of ⁶⁰ Co radionuclides can be reduced to 1.9 mmol / L, and the molar ratio of transition metal nitrate and potassium ferrocyanide can be reduced to 1.0: 1, 5.

The possibility of implementation and technological implementation of the proposed method is confirmed by studies in the laboratory installation, shown in figure 1. The installation includes: storage tank with the initial LRW solution (1), diaphragm pumps (2, 6, 9, 12, 15), a catalytic oxidation column (3), a thermostat (4), a receiving storage tank for the solution after the catalytic column ( 5), mixer-settler reactors (for each operation of the coagulation-precipitation stage and each having a sedimentation sediment separation zone, a decantation separation zone) equipped with a mixing device (7, 10, 13), receiver filters with removable remotely removable cartridges (8, 11, 14), ionoo belt column (16), control valves (B01 ÷ B33).

The proposed method is implemented in the following sequence: the LRW solution received for processing, is adjusted with nitric acid to pH 1-4, depending on the condition of the solution, hydrogen peroxide is introduced to obtain a peroxide concentration in the solution of 0.1-3.3 g / l. The adjusted solution is fed to the first stage of the process — to a catalytic oxidation column operating in a temperature range of 47.5-80 ° C, with a flow rate of 3-15 col.obr./h, while ensuring the contact time of the solution with the catalyst in the range of 50- 130 s

The column is a vertical thermostatic apparatus with a lower solution flow, having a laminar flow zone, a catalysis zone, a gas separation zone. The catalysis zone is cut off by mesh partitions. The prepared catalyst is poured through the upper discharge hatch and sealed by the upper screen. The pore volume of the granular catalyst layer in this case is 5.1-12.5% of the bulk volume. The catalysis zone is a vertical cylindrical column filled with a catalyst in a diameter / height ratio of 1: 3 to 1:15. The catalyst is an inorganic porous carrier uniform in particle size distribution or an anion exchange resin with a grain size of 0.1-0.7 mm, having an active surface area of 2.0-35.0 m ² / g, with an ultrafine homogeneous layer deposited chemically inert in solutions weak nitric acid compositions of metals, oxides, salts with respect to the carrier of 0.01-7.5% by weight, which are oxidation catalysts and, at the same time, catalysts for the decomposition of hydrogen peroxide to form a hydroxyl radical.

The solution that has passed the stage of catalytic oxidative degradation enters the second stage - flocculation-precipitation. In the first operation, transition metal nitrate (Co, Ni, Zn) is introduced into the solution to obtain a concentration of 1.0-12.6 mmol / L, then, with vigorous stirring, a Besfloc K-051C brand flocculant solution is introduced to a concentration of 10-100 mg / l, then a solution of alkali metal ferrocyanide to a concentration of 1.9-19.0 mmol / l. Moreover, between the transition metal nitrate (Co, Ni, Zn) and alkali metal ferrocyanide, a molar ratio of 1.0: 1.5 to 1.0: 1.9 is observed. After complete sedimentation of the precipitate, after 0.5-2.2 h, the clarified part is decanted using intermediate microfiltration at a rate of 5.0-15.0 ml / min · cm ² through a MFK-3G type membrane (pore size 0.45 μm) , MFPK-4G (pore size 0.65 μm) or a TRUMEM type membrane with a pore size of 0.45-0.60 μm. A compact precipitate from the bottom of the apparatus is discharged onto a replaceable filter receiver cartridge and filtered at a rate of 0.2-7.0 ml / min · cm ² through a membrane of the type MFK-1G (pore size 0.15 μm), MFK-2G (size pore 0.25 μm) or a TRUMEM type membrane with a pore size of 0.15-0.25 μm. The decantate and the filtrate are combined and transferred to the next operation flocculation-precipitation stage.

A flocculant of the Besfloc K-051C grade to a concentration of 10-100 mg / l is introduced into the solution with a residual concentration of an alkali metal ferrocyanide of 0.9-6.4 mmol / L into the second operation, and then an alkali metal diethyldithiocarbamate is introduced to a concentration of 10- 100 mg / l, then the solution is stirred for 10-15 minutes and transition metal nitrate (Co, Ni, Zn) is introduced to obtain a concentration of 1.8-12.8 mmol / l. This ensures a twofold excess of transition metal nitrate (Co, Ni, Zn). The separation of sediment in the second operation is carried out similarly to the first. The resulting decantate and filtrate are combined and transferred to the third operation of the flocculation-precipitation stage.

With intensive stirring, the Besfloc K-4000 brand flocculant is introduced into the solution supplied to the third operation to obtain a concentration of 10-100 mg / L and sodium hydroxide solution to a pH of 9-10. The separation of sediment in the third operation is carried out similarly to the first. The second and third operations can be combined without intermediate separation of sediment. Also, all three operations can be carried out sequentially in one apparatus using an intermediate tank for receiving filtrates and decantates.

Finishing from ⁶⁰ Co is carried out on a cation exchange resin selective for transition and heavy metal ions, for example Lewatit MonoPlus TP 207, which is a weakly basic macroporous cation exchange resin with chelate groups of iminodiacetic acid. The solution is passed through an ion-exchange column with a flow rate of 4-10 columns.ob / h with a ratio of the geometry of the bulk layer of the column "diameter / height" from 1:10 to 1:20. The third stage - ion exchange - can be excluded if the salt content of the filtrate after the coagulation-precipitation stage does not exceed 10 g / l.

Example 1

An aluminum-zirconium catalyst ZrO ₂ —PdO / Al ₂ O _{3 was} prepared with a zirconium content of up to 7% and palladium 0.01%. The specific surface area of the prepared catalyst was 2.359 m ² / g.

Table 1 shows the composition of the initial LRW solution. Nitric acid (conc.) Was added to the initial solution to a concentration of 2 g / l and hydrogen peroxide (30%) to 3 g / l.

To co-precipitate ⁶⁰ Co with potassium ferrocyanide, a cobalt nitrate solution was used. As a flocculant, a Besfloc K-051C brand flocculant (table 2) was used.

The experiment was carried out in the above sequence.

Example 2

The LRW processing was carried out analogously to Example 1, however, instead of the ZrO ₂ -PdO / Al ₂ O ₃ catalyst, a platinum catalyst was used, supported on a VP-1AP anion-exchange resin (specific surface area of the prepared catalyst was 18.86 m ² / g) (table 3).

Nickel nitrate was used to precipitate ⁶⁰ Co with potassium ferrocyanide. Diproxamine-157 was used as a flocculant. (table 4)

Example 3

The LRW processing was carried out analogously to Example 1, however, instead of the ZrO ₂ -PdO / Al ₂ O ₃ catalyst, a nickel-ferricyanide catalyst supported on a VP-1AP anion-exchange resin was used (specific surface area of the prepared catalyst was 18.47 m ² / g) (table 5 )

Zinc nitrate solution was used to coprecipitate Co with potassium ferrocyanide. BesflocK-051C brand flocculant was used as a flocculant. (table 6)

The proposed method has the following advantages over the prototype: provides a more complete oxidation of the organic components of LRW in the dynamic mode of operation of the column for significantly less time (50-130 s) of contact with high performance of the column (3-15 columns.ob / h), at lower temperature process (47.5-80 ° C, in the prototype - 98 ° C). The simplicity of the hardware design of the oxidative degradation stage is ensured by using a column with a bulk catalyst bed. The process parameters do not depend on the turbidity, salt composition of the solution and allow a wide range of flow intensities and temperature conditions while maintaining the completeness of oxidation of the organic components of LRW, which allows the processing of opaque solutions (for example, decantates) without a preliminary clarification stage. Process parameters (contact time, productivity) can be quite easily changed both by increasing / decreasing the height of the bulk catalyst layer, and by changing the flow rate. Using the catalytic mechanism of oxidative degradation can significantly reduce the amount of hydrogen peroxide introduced into LRW to 3% vol. (in the prototype 15% of the volume of VAT residue) at the stage of oxidation. The stage of oxidative degradation is carried out in an acidic medium at pH 1-4, which allows the use of synergism from the introduction of a second oxidizing agent, nitric acid, at low concentrations in catalytic oxidation. Mixing the solution in the contact zone (in contrast to the prototype) is carried out by means of intense spontaneous gas evolution in the pore space of the bulk catalyst layer, which increases the flow turbulence and also reduces the contact time. The proposed method eliminates the formation of sludge and the precipitation of oxidative degradation products at the stage of oxidative degradation and therefore does not require the operation of separating the solid phase before the coagulation-precipitation stage (in contrast to the prototype).

The introduction of alkali metal diethyldithiocarbamate is carried out in the second operation of the coagulation-precipitation stage (when the main amount of ⁶⁰ Co (65.1-95.4%) is already transferred to the precipitate of mixed ferrocyanides) in a slightly acidic solution with a pH of 1-4 (in prototype 7-10) containing alkali metal ferrocyanide and a flocculant, which provides the deposition of ⁶⁰ Co, which is in ionic form (most accessible for binding cobalt with diethyldithiocarbamate). The procedure for introducing alkali metal diethyl dithiocarbamate allows (in contrast to the prototype) radioactive cobalt to be initially associated with diethyl dithiocarbamate (with the formation of finely divided, flocculated suspension, determined by the change in turbidity of the LRW solution by 0.4-7.1%), and after 10-15 minutes of contact transition metal nitrate (Co, Ni, Zn) and precipitate the remaining ⁶⁰ Co in the solution both with a precipitate of transition metal diethyldithiocarbamate (Co, Ni, Zn) and a precipitate of transition metal ferrocyanide (Co, Ni, Zn). Since the nitrate of the transition metal (Co, Ni, Zn) is taken in excess, all diethyl dithiocarbamate is separated from the LRW solution with sediment without contaminating the LRW with the introduced organic components. With the simultaneous coprecipitation of transition metal diethyl dithiocarbamate (Co, Ni, Zn) and transition metal ferrocyanide (Co, Ni, Zn), a compact precipitate is formed that is easily separated by microfiltration (unlike the prototype). The proposed method allows to reduce the amount of alkali metal diethyl dithiocarbamate introduced by more than 100 times when using concentrations of the latter 10-100 mg / l (in the prototype 10 g / l). The proposed method allows to obtain the total residual activity of the processed LRW solution <0.9 Bq / L (in the prototype 15 Bq / L) while simultaneously separating ¹³⁷ Cs (up to 99.9%) and ⁶⁰ Co (up to 99.1%) in the first and the second operations of the coagulation-precipitation stage (in the prototype, purification from ¹³⁷ Cs, ⁶⁰ Co is carried out separately).

The technical result of the invention, namely the decrease in the residual specific activity of solutions of CAO and NAO for ⁶⁰ Co and ¹³⁷ Cs to a level of <0.9 Bq / l, allows us to judge the potential implementation of this invention (method) in the technology of processing liquid radioactive waste, in particular decontaminating solutions (containing complexones, surfactants) of radiochemical industries. The resulting solutions after the separation of ⁶⁰ Co and ¹³⁷ Cs radionuclides (with activity less than 0.9 Bq / l) according to [SanPiN 2.6.1.2523 - 09 Radiation Safety Standards NRB - 99/2009] do not belong to the class of radioactive waste and do not require measures to reduce radioactivity, which also allows their use in the future for various technological operations.

Claims (14)

1. The method of purification from ⁶⁰ Co technological solutions of radiochemical production related to medium and low-level waste, including the destruction of organic components in LRW and the separation of radionuclides by filtration, characterized in that the destruction of organic components contained in LRW is carried out by catalytic oxidative thermal decomposition on solid phase the catalyst in dynamic mode in a continuous column type apparatus with the geometry of the bulk catalyst layer in the ratio "diameter / height" - 1:15, and the separation of ⁶⁰ Co from solutions is carried out in three successive operations of coprecipitation of radionuclides with precipitates of mixed transition metal ferrocyanide (the concentration of transition metal nitrate in solution is 10 mmol / l, the molar ratio of transition metal nitrate and potassium ferrocyanide is 1.0: 1.9), hydroxide transition metal using a flocculant and separating the precipitate in each deposition operation and final ion-exchange purification of the filtrate on a cation exchange resin selective for transition metal ions. 2. The method according to claim 1, characterized in that as a solid-phase catalyst for oxidative thermal decomposition of organic components contained in LRW, an aluminum-zirconium catalyst (ZrO ₂ -PdO / Al ₂ O ₃ ) with a zirconium content of up to 7%, palladium is used 0.01% 3. The method according to claim 1, characterized in that as a heterogeneous catalyst for the oxidative thermal degradation of organic components contained in LRW, a platinum catalyst is applied supported on an anion exchange resin VP-1AP with a platinum weight content of 0.5-2%. 4. The method according to claim 1, characterized in that as a heterogeneous catalyst for oxidative thermal decomposition of organic components contained in LRW, a nickel-ferricyanide catalyst deposited on an anion-exchange resin VP-1AP with a weight content of nickel ferricyanide of 5-7% is used. 5. The method according to claim 1, characterized in that the cobalt salt is used as the transition metal salt for coprecipitation of the ⁶⁰ Co radionuclide with potassium ferrocyanide. 6. The method according to claim 1, characterized in that a nickel salt is used as a transition metal salt for the coprecipitation of a ⁶⁰ Co radionuclide with potassium ferrocyanide. 7. The method according to claim 1, characterized in that the zinc salt is used as the transition metal salt for coprecipitation of the ⁶⁰ Co radionuclide with potassium ferrocyanide. 8. The method according to claim 1, characterized in that in the catalytic destruction of organic components of LRW, the ratio "diameter / height" of the bulk catalyst layer in the catalytic column is 1: 5. 9. The method according to claim 1, characterized in that at the stage of coprecipitation of ⁶⁰ Co radionuclides with mixed transition metal ferrocyanides, sodium diethyldithiocarbamate (C _Na-DEDC - 10-100 mg / l) is also used. 10. The method according to claim 1, characterized in that the coprecipitation of radionuclides ⁶⁰ With mixed transition metal ferrocyanides is carried out at a molar ratio of transition metal nitrate and potassium ferrocyanide 1.0: 1.5. 11. The method according to claim 1, characterized in that the concentration of transition metal nitrate added to the solution for coprecipitation of ⁶⁰ Co radionuclides is 1.9 mmol / L. 12. The method according to claim 1, characterized in that as the cation exchange resin selective for transition metal ions, a Lewatit MonoPlus TP 207 resin is used. 13. The method according to claim 1, characterized in that the operations of the coagulation-precipitation separation stage ⁶⁰ Co with mixed transition metal ferrocyanides are carried out in one apparatus of the mixer-settler type without intermediate filtration. 14. The method according to claim 1, characterized in that all the operations of the coagulation-sedimentation separation stage ⁶⁰ Co are carried out in one apparatus of the "mixer-settler" type without intermediate filtration.

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