skip to main content

DOE PAGESDOE PAGES

Title: Hexavalent Actinide Extraction Using N, N-Dialkyl Amides

Recently, efforts towards closing the nuclear fuel cycle have considered oxidizing americium to a hexavalent, linear-dioxo cation for co-recovery with hexavalent U, Np, and Pu from molar nitric acid using solvating extraction ligands such as tri-n-butyl phosphate or diamyl amylphosphonate. This work assesses solvent extraction recovery of sodium bismuthate oxidized americium by N, N-di-(2-ethylhexyl)butyramide (DEHBA), N, N-di-(2-ethylhexyl)isobutyramide (DEHiBA), and N, N-dihexyloctanamide (DHOA). Extraction efficiency between the monoamides was found to increase in the order of DEHiBA < DHOA < DEHBA. For all monoamides, oxidized americium extraction was less than 50% from 4 M HNO 3 and below. Extraction efficiency above 50% was obtained using concentrations of 5 M HNO 3 or higher. The DEHBA extractant provided the highest distribution value of 5.4 at 7 M HNO 3. Distribution values were found to be stable for up to 45 seconds aqueous/organic phase mixing times and indicated decreased reduction of hexavalent americium relative to separations completed with organophosphorus extractants. The simultaneous co-extraction of U, Np, Pu, and Am was demonstrated using DEHiBA, and was found to decrease with increasing atomic number (D U > D Np > D Pu > D Am). Interestingly, a break in recovery was observed where ligher actinides,more » U and Np, were better recovered relative to the heavier actinides, Pu and Am, in this study. This observation seems to be related to differences in the extracted metal complex for light actinides compared to heavy actinides. In conclusion, the metal:ligand stoichiometry was found to be mixed 1:1 and 1:2 species for U and Np while Pu and Am displayed 1:2 stoichiometry.« less
Authors:
 [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Colorado School of Mines, Golden, CO (United States)
  2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
Report Number(s):
INL/JOU-17-41507-Rev000
Journal ID: ISSN 0888-5885
Grant/Contract Number:
AC07-05ID14517
Type:
Accepted Manuscript
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Volume: 56; Journal Issue: 22; Journal ID: ISSN 0888-5885
Publisher:
American Chemical Society (ACS)
Research Org:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5)
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; americium; oxidation; monoamides; solvent extraction; fuel cycle
OSTI Identifier:
1471062

McCann, Kevin, Mincher, Bruce J., Schmitt, Nicholas C., and Braley, Jenifer C.. Hexavalent Actinide Extraction Using N,N-Dialkyl Amides. United States: N. p., Web. doi:10.1021/acs.iecr.7b01181.
McCann, Kevin, Mincher, Bruce J., Schmitt, Nicholas C., & Braley, Jenifer C.. Hexavalent Actinide Extraction Using N,N-Dialkyl Amides. United States. doi:10.1021/acs.iecr.7b01181.
McCann, Kevin, Mincher, Bruce J., Schmitt, Nicholas C., and Braley, Jenifer C.. 2017. "Hexavalent Actinide Extraction Using N,N-Dialkyl Amides". United States. doi:10.1021/acs.iecr.7b01181. https://www.osti.gov/servlets/purl/1471062.
@article{osti_1471062,
title = {Hexavalent Actinide Extraction Using N,N-Dialkyl Amides},
author = {McCann, Kevin and Mincher, Bruce J. and Schmitt, Nicholas C. and Braley, Jenifer C.},
abstractNote = {Recently, efforts towards closing the nuclear fuel cycle have considered oxidizing americium to a hexavalent, linear-dioxo cation for co-recovery with hexavalent U, Np, and Pu from molar nitric acid using solvating extraction ligands such as tri-n-butyl phosphate or diamyl amylphosphonate. This work assesses solvent extraction recovery of sodium bismuthate oxidized americium by N,N-di-(2-ethylhexyl)butyramide (DEHBA), N,N-di-(2-ethylhexyl)isobutyramide (DEHiBA), and N,N-dihexyloctanamide (DHOA). Extraction efficiency between the monoamides was found to increase in the order of DEHiBA < DHOA < DEHBA. For all monoamides, oxidized americium extraction was less than 50% from 4 M HNO3 and below. Extraction efficiency above 50% was obtained using concentrations of 5 M HNO3 or higher. The DEHBA extractant provided the highest distribution value of 5.4 at 7 M HNO3. Distribution values were found to be stable for up to 45 seconds aqueous/organic phase mixing times and indicated decreased reduction of hexavalent americium relative to separations completed with organophosphorus extractants. The simultaneous co-extraction of U, Np, Pu, and Am was demonstrated using DEHiBA, and was found to decrease with increasing atomic number (DU > DNp > DPu > DAm). Interestingly, a break in recovery was observed where ligher actinides, U and Np, were better recovered relative to the heavier actinides, Pu and Am, in this study. This observation seems to be related to differences in the extracted metal complex for light actinides compared to heavy actinides. In conclusion, the metal:ligand stoichiometry was found to be mixed 1:1 and 1:2 species for U and Np while Pu and Am displayed 1:2 stoichiometry.},
doi = {10.1021/acs.iecr.7b01181},
journal = {Industrial and Engineering Chemistry Research},
number = 22,
volume = 56,
place = {United States},
year = {2017},
month = {5}
}