Selective decontamination of caesium and strontium in concentrates from reprocessing plant evaporators with crown ethers by transport through supported liquid membranes
The concentrates from reprocessing plant evaporators have to be stored in geological storage sites in view of their strong caesium, strontium and actinides activity. These elements, contained in acid and high sodium nitrate content liquid waste, are removed by means of selective extractants, using the supported liquid membrane technique (SLM). Actinide removal is done by means of an octyl N.N diisobutyl carbamoyl methyl phosphine oxyde (CMPO) based liquid membrane, whereas the removal of the caesium and strontium involves crown ethers. For the extraction of strontium, the most lipophilic extractant, DtBu18 C6, enables higher strontium transfer kinetics to be attained than with DC18 C6. As regards caesium, the extremely lipophilic nDec B21 C7 is the most efficient. Caesium cannot however be quantitatively removed, due to the competition of the very high content of sodium ions present in the concentrate. Stable membranes are obtained with DC18 C6 or DtBu18 C6 diluted in alkylbenzene compounds (hexylbenzene-tridecylbenzene) with an added phase modifier such as decanol or especially isotridecanol. The highest strontium transfer kinetics were obtained with the DC18 C6/hexylbenzene/isotridecanol mixture.
Bibliographic Reference: EUR 14465 FR (1993) 319 pp., FS, ECU 36
ISBN: ISBN 92-826-2729-2
Record Number: 199310334 / Last updated on: 1994-11-29
Original language: fr
Available languages: fr