This title appears in the Scientific Report : 2016 

Nitric acid extraction into the TODGA/TBP solvent
McLachlan, Fiona (Corresponding author)
Greenough, Katie / Geist, Andreas / McLuckie, Bliss / Modolo, Giuseppe / Wilden, Andreas / Taylor, Robin
Nukleare Entsorgung und Reaktorsicherheit; IEK-6
Solvent extraction and ion exchange, 34 (2016) 4, S. 334-346
Philadelphia, PA Taylor & Francis 2016
Journal Article
Safety of ACtinide Separation proceSSes
Nuclear Waste Management
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The tridentate diglycolamide ligand N,N,N′,N′-tetraoctyl diglycolamide (TODGA) shows many interesting properties and is a very good extractant for the minor actinides (MAs) and lanthanides but, due to its low loading capacity, requires a phase modifier when used in a solvent extraction process. Consequently, applications of TODGA in conjunction with tri-butyl phosphate (TBP) in novel DIAMEX and SANEX processes for recovering MAs have been reported. However, TODGA and TBP also extract nitric acid and this has a significant influence on process performance. Here new distribution data for the extraction of nitric acid into solvent phases containing TODGA and TBP have been collected and modeled using an equilibrium-based approach accounting for nitric acid activities in the aqueous phase. Models for the extraction of nitric acid using the individual extractants were obtained using a variety of complexes and these were then combined to give the extraction of the mixed TODGA and TBP solvent. Using this approach, the nitric acid extraction of the mixed TODGA/TBP system can be reliably reproduced indicating that no significant synergistic or antagonistic complexes are formed in solution.