METHOD AND DEVICE FOR CLEANING URANYL NITRATE FROM FISSION PRODUCTS

摘要

FIELD: radiochemical industry. ^ SUBSTANCE: 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. ^ EFFECT: enhanced cleaning efficiency and economic efficiency of process. ^ 7 cl, 2 ex