Demonstration of a TODGA‐Based Continuous Counter‐Current Extraction Process for the Partitioning of Actinides from a Simulated PUREX Raffinate, Part II: Centrifugal Contactor Runs

Abstract

The efficiency of the partitioning of trivalent actinides from a PUREX raffinate is demonstrated with a TODGA þ TBP extractant mixture dissolved in an industrial aliphatic solvent TPH. Based on the results of cold and hot batch extraction studies and with the aid of computer code calculations, a continuous counter-current process is developed and two flowsheets are tested using miniature centrifugal contactors. The feed solution used is a synthetic PUREX raffinate, spiked with 241 Am, 244 Cm, 252 Cf, 152 Eu, and 134 Cs. More than 99.9% of the trivalent actinides and lanthanides are extracted and back-extracted and very high decontamination factors are obtained for most fission products. The co-extraction of zirconium, molybdenum, and palladium is prevented using oxalic acid and HEDTA. However, 10% of ruthenium is extracted and only 3% is back-extracted using diluted nitric acid. The experimental steady-state concentration profiles of important solutes are determined and compared with model calculations and good agreement is generally obtained.

Dynamic light scattering study on the aggregation behaviour of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) and its correlation with the extraction behaviour of metal ions

“…Amongst the long chain derivatives of diglycolamides, N,N,N 0 ,N 0 -tetraoctyl diglycolamide (TODGA) was found to be the most promising extractant for actinide partitioning and has been extensively studied in our laboratory as well as elsewhere [4][5][6][7][8][9][10][11]. However, the studies of metal-TODGA complexes in the organic solvents show unusual interesting features that are difficult to reconcile within the framework of the traditional coordination chemistry interpretations.…”

A review of the demonstration of innovative solvent extraction processes for the recovery of trivalent minor actinides from PUREX raffinate

“…The addition of TBP not only improved the hydrodynamic properties but also increased the loading capacity of the extractant and reduced the tendency to third-phase formation. In 2006, Forschungszentrum Jülich performed two tests in centrifugal extractors in cooperation with the Institute for Transuranium Elements (ITU) and CEA Marcoule [29].…”

“…using TODGA (Fig. 3) as extracting agent [23,28,29]. A hydrophilic complexing agent selective for An(III) over Ln(III) such as DTPA (diethylenetriaminepentaacetic acid) is used for back-extracting An(III) from the loaded organic phase.…”

Evaluation of hydrodynamic suitability of N,N-didodecyl N′,N′-di-octyl diglycolamide: a potential candidate for minor actinide partitioning

“…Subsequently, during 2000s, the secondary waste disposal problems associated with phosphine oxide based extractants were addressed by the development of CHON based substituted malonamide extractants such as N,N 0 -dimethyl-N,N 0 -dibutyl tetradecyl malonamide and N,N 0 -dimethyl-N,N 0 -dioctyl hexylethoxy malonamide, owing to their incinerable nature [5]. Since last decade, diglycolamide-based extractants such as N,N,N 0 ,N 0 -tetraoctyl diglycolamide (TODGA) and N,N,N 0 ,N 0 -tetra-2-ethylhexyl diglycolamide (T2EHDGA) have been found to be highly promising because of their efficient extraction and stripping behaviour in the separation of MA from HLLW [6][7][8][9][10][11][12][13][14][15][16][17]. Though these extractants have many promising features, they also have some limitations regarding third phase formation.…”