Combining CMPO and HEH[EHP] for Separating Trivalent Lanthanides from the Transuranic Elements |
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Authors: | Jenifer C. Braley Jennifer C. Carter |
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Affiliation: | 1. Department of Chemistry and Geochemistry , Colorado School of Mines , Golden , CO , USA;2. Pacific Northwest National Laboratory , Richland , WA , USA |
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Abstract: | Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide (CMPO) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. The lanthanides and americium can be co-extracted from HNO3 into 0.2 mol/L CMPO + 1.0 mol/L HEH[EHP] in n-dodecane. The extraction is relatively insensitive to the HNO3 concentration within 0.1–5 mol/L HNO3. Americium can be selectively stripped from the CMPO/HEH[EHP] solvent into a citrate-buffered N-(2-hydroxyethyl)ethylenediaminetriacetic acid solution. Separation factors >14 can be achieved in the range pH 2.5–3.7, and the separation factors are relatively insensitive to pH—a major advantage of this solvent formulation. |
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Keywords: | Lanthanide separation actinide separation CMPO HEH[EHP] PC88A |
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