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Method for separating valuable components from impurities in solid-phase product of radioactive materials. RU patent 2253159.

Method for separating valuable components from impurities in solid-phase product of radioactive materials. RU patent 2253159.

FIELD: decontamination of radioactive materials.

SUBSTANCE: solid product that incorporates radioactive impurities is dissolved in nitric acid, this being followed by multistage extraction. Part of extractant is passed to multistage extractor in the form of extract produced during pre-extraction of valuable components from dissolved product. Upon extraction water phase returns for dissolving operation. Impurities are localized and concentrated in head part of solid product recovery process scheme.

EFFECT: reduced amount of aqua-tail solutions.

1 cl, 3 dwg, 1 tbl

 


 

IPC classes for russian patent Method for separating valuable components from impurities in solid-phase product of radioactive materials. RU patent 2253159. (RU 2253159):

G21C19/46 - Aqueous processes
C01G43 - Compounds of uranium
Another patents in same IPC classes:
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Proposed method includes crystallization of uranyl hexahydro-nitrate from solution by cooling it down. In the process uranyl nitrate solution is pre-evaporated to uranium concentration of 800-1300 g/l and to nitric acid concentration of 0.5-3.0 mole/l. Crystallization is conducted in concurrent flow of uranyl hexahydro-nitrate crystals formed in the process and mother solution while permanently stirring and cooling solution to 15-30 oC. Crystals are separated from mother solution and washed in concurrent flow at 15-30 oC in wash solution containing 250-300 g/l of uranium and 3.0-6.0 mole/l of nitric acid. Then crystals are taken out and dried. Device implementing this method has crystallization vat made in the form of externally cooled tube. In addition vertically disposed crystallization vat accommodates blade mixer. Uranyl nitrate solution feed union is disposed in top part of crystallization vat. Bottom part of the latter is placed coaxially with wash-over string and secured in hole of its lid provided with pipe union for joint outlet of mother solution and waste wash solution. Bottom part of wash-over string is joined at certain angle to auger-accommodating inclined tube. Top part of inclined tube is provided with pipe union for taking out dried uranyl hexahydro-nitrate crystals and wash solution feed union. Pipe union for taking out dried crystals is disposed above that wash solution feed union. Pipe union for feeding uranyl nitrate solution is level with wash solution feed union and with water seal.
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Method for recovering irradiated nuclear fuel (alternatives) Method for recovering irradiated nuclear fuel (alternatives) / 2249267
Proposed method meant for recovering irradiated nuclear fuel to obtain joint solution of U and Pu includes extraction of U, Pu, Np, and Te from nitric acid solution by means of 30% solution of tributyl phosphate and separation of Np and Te. Next re-extraction of Pu is effected by means of depleted or regenerated four-valence uranium solution. The latter is supplied to central part of Pu re-extraction unit at flowrate ensuring weight proportion of Pu : U = 1 : 4 in re-extract. At the same time solution of 0.1 - 0.7 mole/l of nitric acid is fed to end of unit at flowrate excluding breakthrough of U(IV) with extract of U(VI). Joint re-extraction of plutonium and part of uranium is also conducted by completing agent solution supplied in constant composition and at flowrate affording complete re-extraction of plutonium. At the same time solution of 0.1 - 0.7 mole/l of nitric acid is fed to end of unit at flowrate ensuring desired amount of uranium supply to mixed re-extract.
Method for separating valuable components from impurities in solid-phase product of radioactive materials Method for separating valuable components from impurities in solid-phase product of radioactive materials / 2253159
Solid product that incorporates radioactive impurities is dissolved in nitric acid, this being followed by multistage extraction. Part of extractant is passed to multistage extractor in the form of extract produced during pre-extraction of valuable components from dissolved product. Upon extraction water phase returns for dissolving operation. Impurities are localized and concentrated in head part of solid product recovery process scheme.
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