EXTRACTION MIXTURE FOR EXTRACTING TPE AND RARE EARTH FROM HIGHLY ACTIVE RAFFINATE OF OAT GRAIN PROCESSING AND METHOD OF ITS APPLICATION Russian patent published in 2020 - IPC C22B60/02 C22B59/00 C22B3/40 

FIELD: chemical and physical processes.

SUBSTANCE: inventions relate to the field of radiochemical technology and can be used in handling highly active raffinate of Purex-process of spent nuclear fuel (SNF) processing. Method of extracting transplutonium elements (TPE) and rare-earth elements from highly active raffinate from SNF processing includes their combined extraction with an extraction mixture, washing extract from impurities, re-extraction of nitric acid in presence of salting-out agent, re-extraction of mainly TPE and part of rare-earth elements with solution of diethylenetriaminepentaacetic acid in buffer medium, extraction of remaining in organic phase of rare-earth elements with carbonate solution with complexing agent at stage of regeneration of recycled extraction agent. An extraction mixture is used which contains, as an extractant, tetraoctylamide diglycolic acid in a diluent from a series of paraffin and isoparaffin hydrocarbons or a mixture thereof with an additive of a polar modifier, in form of a water-insoluble limit unsubstituted alcohol or a mixture of limiting unsubstituted alcohols with number of carbon atoms of not less than 9 but not more than 10, with content of alcohol in the extraction mixture of 0.5–10 % by volume. Extract is washed with removal of Mo, Zr, as well as traces of Pu and Np, using a nitric solution of a strong complexing agent destructed by nitric acid on a whole or with formation of volatile products. Re-extraction of nitric acid is combined with re-extraction of TPE with DTPA solution, removing nitric acid in the presence of a buffer reagent or a mixture of buffer reagents. Extract of REE is treated with carbonate solution containing complexon and demulsifier, simultaneously removing main degradation products of primary alcohols.

EFFECT: method ensures safety of the process, with purification of fraction of transplutonium elements from rare-earth elements in 15 times at losses not exceeding 0,1 %.

4 cl, 1 tbl, 1 ex, 1 dwg