Demonstration of T2EHDGA Based Process for Actinide Partitioning Part II: Counter-Current Extraction Studies

Abstract

Counter-current mixer-settler studies for actinide partitioning were carried using N,N,N ,N -tetra-2-ethylhexyl diglycolamide (T2EHDGA) as the extractant. The feed solution was Simulated High Level Waste of Pressurized Heavy Water Reactor (PHWR-SHLW) origin spiked with 241 Am, 244 Cm, 152 Eu, 137 Cs, 85,89 Sr, 59 Fe, 106 Ru, 109 Pd, 95 Zr, and 99 Mo tracers. The organic stream was 0.1 M T2EHDGA + 5% isodecanol in n-dodecane. Extraction, scrubbing, and stripping experiments were performed by maintaining an organic to aqueous phase ratio of 1. More than 99.9% of the trivalent actinides and lanthanides were extracted in four stages, and the decontamination factors (D.F.) values were >10 3 obtained for most fission products. The co-extraction of Zr and Pd was prevented by the addition of oxalic acid and N-(2-hydroxyethyl)-ethylenediamine-triacetic acid (HEDTA) into the feed solution. However, ∼20% Ru and 10% Mo was extracted into the organic phase, which was successfully scrubbed using a mixture of 0.2 M oxalic acid and 0.1 M HEDTA in 5 M HNO 3 . Finally, the extracted actinides and lanthanides were quantitatively stripped with 0.2 M HNO 3 . Raffinate of the extraction cycle was found to be free from any alpha activity.

Hollow fiber supported liquid membrane studies using a process compatible solvent containing calix[4]arene-mono-crown-6 for the recovery of radio-cesium from nuclear waste

“…Simulated high level waste (SHLW) was prepared in the laboratory as per the standard composition (see the Supporting Information). The composition of this solution was equivalent to the generation of HLW from the fuel reprocessing of a typical Pressurized Heavy Water Reactor (PHWR) of ~6500 MWD/T burn up, 3 years cooling and ~800 litres of the waste solution per tonne of the spent fuel [31][32][33]. The composition of the SHLW, containing 0.32 g/L Cs(I), was confirmed by ICP-AES analysis.…”

Extractants for rare earth metals

“…The presence of ether oxygen between the two amide groups in the DGA increases the extraction of lower actinides due to the active education of tridentate complexes. N,N,N',N'-Tetraoctyldiglycolamide (TODGA) 44g and N,N,N',N'-Tetra-2-ethylhexyldiglycolamide (TEH-DGA) 44j [32,33] were considered as the most promising extractants for the lower actinides among diglycolamides. It is due to the influence of the nature of the alkyl substituents of diglycolamide.…”

“…Присутст-вие эфирного кислорода между двумя амидными группами в DGA повы-шает извлечение низших актиноидов вследствие активного образования тридентантных комплексов. Как наи-более перспективные экстрагенты для низших актинидов среди дигликольа-мидов рассматриваются N,N,N',N'-тетраоктилдигликольамид (ТОДГА) 44ж и N,N,N',N'-тетра-2-этилгексил-дигликольамид (ТЭГДГА) 44к [32,33].…”

New extractant N,N′-dimethyl-N,N′-dicyclohexyl-2,(2′-dodecyloxyethyl)-malonamide (DMDCDDEMA) for radiotoxic acidic waste remediation: Synthesis, extraction and supported liquid membrane transport studies

“…1(a)), and DMDOHEMA (N,N 0 -dimethyl-N,N 0 -dioctyl-2-(2-(hexyloxy)-ethyl)-malonamide Fig. 1(b)) [21][22][23][24][25][26]. These extractants were also evaluated as carrier ligands and stationary phase in supported liquid membrane (SLM) and extraction chromatography system, respectively.…”