Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO) and bis-(2-ethylhexyl) phosphoric acid (HDEHP) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. Co-extraction of americium and the lanthanide elements from nitric acid solution is possible with a solvent mixture consisting of 0.1-M CMPO plus 1-M HDEHP in n-dodecane. Switching the aqueous-phase chemistry to a citrate-buffered solution of diethylene triamine pentaacetic acid (DTPA) allows for selective stripping of americium, separating it from the lanthanide elements. Potential strategies for managing molybdenum and zirconium (both of which co-extract with americium and the lanthanides) have been developed. The work presented here demonstrates the feasibility of combining CMPO and HDEHP into a single extraction solvent for recovering americium from high-level waste and its separation from the lanthanides.
Revised: May 30, 2013 |
Published: April 8, 2013
Citation
Lumetta G.J., A.V. Gelis, J.C. Braley, J.C. Carter, J.W. Pittman, M.G. Warner, and G.F. Vandegrift. 2013.The TRUSPEAK Concept: Combining CMPO and HDEHP for Separating Trivalent Lanthanides from the Transuranic Elements.Solvent Extraction and Ion Exchange 31, no. 3:223-236.PNNL-SA-81137.doi:10.1080/07366299.2012.670595