An Advanced TALSPEAK Concept Using 2-Ethylhexylphosphonic Acid Mono-2-Ethylhexyl Ester as the Extractant

Lumetta, Gregg J.; Casella, Amanda J.; Rapko, Brian M.; Levitskaia, Tatiana G.; Pence, Natasha; Carter, Jennifer C.; Niver, Cynthia M.; Smoot, Margaret R.

doi:10.1080/07366299.2014.985920

Cited by 30 publications

(40 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This principle was exploited in the TALSPEAK process, 10,11,12 developed more than 50 years ago, using DTPA (diethylenetriaminepentaacetic acid, Figure 1) to complex An(III). This principle was further developed and improved mainly in the USA, 13,14,15 France 16,17 and Japan. 18 BTP, 19,20 BTBP 21,22,23 and BTPhen 24,25 made hydrophylic by sulfonation (i.e.…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Laser Fluorescence Spectroscopy Study of the Coordination Chemistry of a Hydrophilic CHON [1,2,3-Triazol-4-yl]pyridine Ligand with Cm(III) and Eu(III)

et al. 2017

View full text Add to dashboard Cite

The complexation of Cm(III) and Eu(III) with the novel i-SANEX complexing agent 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl]pyridine (PTD) was studied by time-resolved laser fluorescence spectroscopy (TRLFS). The formation of 1:3, 1:2, and 1:1 metal/ligand complexes was identified upon increasing PTD concentration in 10 mol/L HClO and in 0.44 mol/L HNO solutions. For all these complexes, stability constants were determined at different acid concentrations. Though under the extraction conditions proposed for an An/Ln separation process, that is, for 0.08 mol/L PTD in 0.44 mol/L HNO, 1:3 complexes represent the major species, a significant fraction of 1:2 complexes was found. This is caused by ligand protonation, and results in lower Eu(III)/Am(III) separation factors compared to SO-Ph-BTP, until now considered the i-SANEX reference ligand. Focused extraction studies performed at lower proton concentration, where the 1:3 complex is formed exclusively, confirm this assumption.

show abstract

Section: Introductionmentioning

confidence: 99%

Time-Resolved Laser Fluorescence Spectroscopy Study of the Coordination Chemistry of a Hydrophilic CHON [1,2,3-Triazol-4-yl]pyridine Ligand with Cm(III) and Eu(III)

et al. 2017

View full text Add to dashboard Cite

show abstract

“…An alternative was sought to overcome these limitations of TALSPEAK. [15][16][17][18][19][20][21] A new chemical system was investigated in-depth based on the use of a combination of 2ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH [EHP] or PC88A) and N- (2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA) in a citrate-buffered system (Figure 1). Optimal process conditions were found for 1.0 mol/L HEH [EHP] in n-dodecane as the solvent, and a feed solution containing the metal ions and 0.125 mol/L HEDTA and 0.6 mol/L citrate at pH 2.6.…”

Section: Introductionmentioning

confidence: 99%

An Advanced TALSPEAK Concept for Separating Minor Actinides. Part 2. Flowsheet Test with Actinide-spiked Simulant

Wilden

Lumetta

Sadowski

et al. 2017

Solvent Extraction and Ion Exchange

Self Cite

View full text Add to dashboard Cite

An Advanced TALSPEAK counter-current flowsheet test was demonstrated using a simulated feed spiked with radionuclides in annular centrifugal contactors. A solvent comprising 2ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP] or PC88A) in n-dodecane was used to extract trivalent lanthanides away from the trivalent actinides Am 3+ and Cm 3+ , which were preferentially complexed in a citrate buffered aqueous phase with N-(2hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA). In a 24-stages demonstration test the trivalent actinides were efficiently separated from the trivalent lanthanides with decontamination factors >1,000, demonstrating the excellent performance of the chemical system. Clean actinide and lanthanide product fractions and spent solvent with very low contaminations were obtained. The results of the process test are presented and discussed.

show abstract

“…More recently, a modification to the TALSPEAK concept has been investigated. [27][28] The primary advantage of the modified process, the Advanced TALSPEAK system, compared to the conventional TALSPEAK process is that it is not highly sensitive to changes in the pH, making it a more attractive option for industrial application. In this Advanced Figure 1) is used as the actinide holdback complexant.…”

Section: Introductionmentioning

confidence: 99%

“…However, single-stage efficiency tests conducted using a 2-cm centrifugal contactor revealed that low extraction rates for Sm, Eu, and Gd in the previously reported Advanced TALSPEAK system compromise the actinide/lanthanide separation factors achievable in such contactors. [28] This paper reports on investigations conducted to improve the extraction rates in the Advanced TALSPEAK system to meet the requirements of centrifugal contactor separation systems. Two approaches are considered: (i) optimizing the citrate buffer performance by varying its concentration and the solution pH using HEDTA as the MA holdback complexant, and (ii) replacing HEDTA with an alternative holdback complexant.…”

Section: Introductionmentioning

confidence: 99%

An Advanced TALSPEAK Concept for Separating Minor Actinides. Part 1. Process Optimization and Flowsheet Development

Lumetta

Levitskaia

Wilden

et al. 2017

Solvent Extraction and Ion Exchange

Self Cite

View full text Add to dashboard Cite

A solvent extraction system was developed for separating trivalent actinides from lanthanides. This "Advanced TALSPEAK" system uses 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester 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 was chosen for further study. Batch distribution measurements indicate that the separation of americium 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. So, 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.

show abstract

An Advanced TALSPEAK Concept Using 2-Ethylhexylphosphonic Acid Mono-2-Ethylhexyl Ester as the Extractant

Cited by 30 publications

References 14 publications

Time-Resolved Laser Fluorescence Spectroscopy Study of the Coordination Chemistry of a Hydrophilic CHON [1,2,3-Triazol-4-yl]pyridine Ligand with Cm(III) and Eu(III)

Time-Resolved Laser Fluorescence Spectroscopy Study of the Coordination Chemistry of a Hydrophilic CHON [1,2,3-Triazol-4-yl]pyridine Ligand with Cm(III) and Eu(III)

An Advanced TALSPEAK Concept for Separating Minor Actinides. Part 2. Flowsheet Test with Actinide-spiked Simulant

An Advanced TALSPEAK Concept for Separating Minor Actinides. Part 1. Process Optimization and Flowsheet Development

Contact Info

Product

Resources

About