An Advanced TALSPEAK Concept for Separating Minor Actinides. Part 1. Process Optimization and Flowsheet Development. Issue 6 (19th September 2017)

• Record Type: Journal Article
• Authors: Lumetta, Gregg J.; Levitskaia, Tatiana G.; Wilden, Andreas; Casella, Amanda J.; Hall, Gabriel B.; Lin, Leigh; Sinkov, Sergey I.; Law, Jack D.; Modolo, Giuseppe
• Is Part Of: Solvent extraction and ion exchange. Volume 35:Issue 6(2017)
• Page Start: 377
• Page End: 395
• Publication Date: 2017-09-19
• Subjects: Actinide separation -- HEH[EHP] -- lanthanide separation -- PC88A -- TALSPEAK; Solvent extraction -- Periodicals; Ion exchange -- Periodicals; 660.284248
• DOI: 10.1080/07366299.2017.1368901
• Languages: English
• ISSNs: 0736-6299

Abstract

ABSTRACT: A solvent extraction system was developed for separating trivalent actinides from lanthanides. This "Advanced TALSPEAK" system uses 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) to extract the lanthanides into an n- dodecane-based solvent; the actinides are retained in a citrate-buffered aqueous phase by complexation to a polyaminocarboxylate ligand. Several aqueous-phase ligands were investigated, and N -(2-hydroxyethyl)ethylenediamine- N, N', N' -triacetic acid (HEDTA) was chosen for further study. Batch distribution measurements indicate that the separation of americium (Am) from the light lanthanides increases as the pH increases. However, previous investigations indicated that the extraction rates for the heavier lanthanides decrease with increasing pH. Therefore, a balance between these competing effects is required. An aqueous phase at pH 2.6 was chosen for further process development, because this offered optimal separation. Centrifugal-contactor single-stage efficiencies were measured to characterize the system's performance under flow conditions, and an Advanced TALSPEAK flowsheet was designed.