Diamylamylphosphonate Solvent Extraction of Am(VI) from Nuclear Fuel Raffinate Simulant Solution

Bruce J. Mincher, Leigh R. Martin, Nicholas C. Schmitt

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

The separation of hexavalent americium from the lanthanides in simulated PUREX raffinate solution using 1 M diamylamylphosphonate in dodecane extraction was investigated. Hexavalent americium was prepared using room-temperature sodium bismuthate oxidation. Under these conditions the majority of the lanthanides were not oxidized and remained inextractable. A separation factor of ~50 was provided for americium from europium over the nitric acid concentration range 6-7 M. Cerium was the exception with oxidation to Ce IV resulting in its co-extraction with Am VI. However, since americium is readily reduced to Am III it was easily stripped with a dilute acidic solution of hydrogen peroxide. Although hydrogen peroxide also reduces cerium, it does so slowly, and a selective americium strip was achieved, with a separation factor of as high as 35. Alternatively, since americium spontaneously reduced in the loaded organic phase, samples allowed to stand for 2 hours could be selectively stripped of americium by contact with 1 M HNO 3 containing no additional reagents. Further, the separation was demonstrated using solutions containing macro-amounts of cerium and americium. The implications for use in fuel cycle separations are discussed.

Original languageEnglish
Pages (from-to)445-456
Number of pages12
JournalSolvent Extraction and Ion Exchange
Volume30
Issue number5
DOIs
StatePublished - Aug 2012
Externally publishedYes

Funding

Work supported by the U.S. Department of Energy, Assistant Secretary for Nuclear Energy, under the Fuel Cycle Research and Development Minor Actinide Separations σ -team; DOE Idaho Operations Office Contract DE-AC07-05ID14517. The authors thank E.P. Horwitz, for initially suggesting the use of DAAP as an AmVI extraction ligand.

Keywords

  • Americium
  • americium extraction
  • americium oxidation
  • minor actinides
  • phosphonate
  • separation
  • sodium bismuthate

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