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Title: Mixed monofunctional extractants for trivalent actinide/lanthanide separations: TALSPEAK-MME

The basic features of an f-element extraction process based on a solvent composed of equimolar mixtures of Cyanex-923 (a mixed trialkyl phosphine oxide) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) extractants in n-dodecane are investigated in this report. This system, which combines features of the TRPO and TALSPEAK processes, is based on co-extraction of trivalent lanthanides and actinides from 0.1 to 1.0 M HNO3 followed by application of a buffered aminopolycarboxylate solution strip to accomplish a Reverse TALSPEAK selective removal of actinides. This mixed-extractant medium could enable a simplified approach to selective trivalent f-element extraction and actinide partitioning in a single process. As compared with other combined process applications in development for more compact actinide partitioning processes (DIAMEX-SANEX, GANEX, TRUSPEAK, ALSEP), this combination features only monofunctional extractants with high solubility limits and comparatively low molar mass. Selective actinide stripping from the loaded extractant phase is done using a glycine-buffered solution containing N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) or triethylenetetramine-N,N,N',N'',N''',N'''-hexaacetic acid (TTHA). Lastly, the results reported provide evidence for simplified interactions between the two extractants and demonstrate a pathway toward using mixed monofunctional extractants to separate trivalent actinides (An) from fission product lanthanides (Ln).
Authors:
 [1] ;  [1]
  1. Washington State Univ., Pullman, WA (United States)
Publication Date:
OSTI Identifier:
1245822
Report Number(s):
INL/JOU--15-34089
Journal ID: ISSN 0736-6299
Grant/Contract Number:
AC07-05ID14517
Type:
Accepted Manuscript
Journal Name:
Solvent Extraction and Ion Exchange
Additional Journal Information:
Journal Volume: 33; Journal Issue: 7; Journal ID: ISSN 0736-6299
Publisher:
Taylor and Francis
Research Org:
Idaho National Laboratory, Idaho Falls, ID (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS ALSPEAK; lanthanide; actinide; solvent extraction; Cyanex 923; HEH[EHP]