METHOD FOR REGENERATION OF SILVER FROM ACTINOID-CONTAINING NITRIC-ACID SOLUTION Russian patent published in 2021 - IPC C22B11/00 G21F9/04 C01G5/00 

FIELD: radiochemistry.

SUBSTANCE: invention relates to the field of radiochemistry and can be used in the production of MOX fuel in the technology of reprocessing spent nuclear fuel (SNF). Regeneration of silver from an actinide-containing nitric acid solution with a nitric acid concentration of 190-380 g / l is carried out by introducing reducing agents, neutralizing the solution, reducing silver to metal, separating the suspension, washing the precipitate and dissolving it. Carbohydrazide and ascorbic acid are used as reducing agents. The molar ratio of carbohydrazide and ascorbic acid to the silver contained in the solution is (2.2÷6.1):1 and (0.9 - 2.0):1. The reduction is carried out in the process of neutralization at a temperature of 15-25°C with 8-15 mol / l with an alkali metal hydroxide solution, which is dosed at a rate of 2-20 vol.% / min to a residual concentration of nitric acid in the solution of 130-224 g / l. After neutralization, the resulting suspension is stirred for 10-30 minutes, and then sedimentation of the metallic silver precipitate is carried out in the bottom of the precipitator for 60-360 minutes. 90-92% of the solution volume is decanted, then the precipitate is washed and dissolved in nitric acid to obtain a nitric acid solution of silver regenerate.

EFFECT: invention makes it possible to extract silver from actinide-containing solutions with an output of more than 84% of silver into the regenerate, when carrying out in one apparatus the operation of precipitation, decantation of mother liquor and washing solutions, dissolving the precipitate to obtain a nitric acid solution of silver regenerate.

8 cl, 32 tbl, 8 ex, 1 dwg