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Title: Americium separations from high salt solutions

Abstract

Americium (III) exhibits an unexpectedly high affinity for anion-exchange material from the high-salt evaporator bottoms solutions--an effect which has not been duplicated using simple salt solutions. Similar behavior is observed for its lanthanide homologue, Nd(III), in complex evaporator bottoms surrogate solutions. There appears to be no single controlling factor--acid concentration, total nitrate concentration or solution ionic strength--which accounts for the approximately 2-fold increase in retention of the trivalent ions from complex solutions relative to simple solutions. Calculation of species activities (i.e., water, proton and nitrate) in such concentrated mixed salt solutions is difficult and of questionable accuracy, but it is likely that the answer to forcing formation of anionic nitrate complexes of americium lies in the relative activities of water and nitrate. From a practical viewpoint, the modest americium removal needs (ca. 50--75%) from nitric acid evaporator bottoms allow sufficient latitude for the use of non-optimized conditions such as running existing columns filled with older, well-used Reillex HPQ. Newer materials, such as HPQ-100 and the experimental bifunctional resins, which exhibit higher distribution coefficients, would allow for either increased Am removal or the use of smaller columns. It is also of interest that one of the experimental neutral-donor solid-support extractants, DHDECMP,more » exhibits a similarly high level of americium (total alpha) removal from EV bottoms and is much less sensitive to total acid content than commercially-available material.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Los Alamos National Laboratory, Los Alamos, NM (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
753372
Report Number(s):
LA-13676-MS
TRN: US0003137
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Mar 2000
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; AMERICIUM; ION EXCHANGE; PARAMETRIC ANALYSIS; ION EXCHANGE MATERIALS; SORPTIVE PROPERTIES; ORGANIC SOLVENTS; SOLVENT EXTRACTION; RADIOACTIVE WASTE PROCESSING

Citation Formats

Barr, Mary E, Jarvinen, Gordon D, Schulte, Louis D, Stark, Peter C, Chamberlin, Rebecca M, Abney, Kent D, Ricketts, Thomas E, Valdez, Yvette E, and Bartsch, Richard A. Americium separations from high salt solutions. United States: N. p., 2000. Web. doi:10.2172/753372.
Barr, Mary E, Jarvinen, Gordon D, Schulte, Louis D, Stark, Peter C, Chamberlin, Rebecca M, Abney, Kent D, Ricketts, Thomas E, Valdez, Yvette E, & Bartsch, Richard A. Americium separations from high salt solutions. United States. https://doi.org/10.2172/753372
Barr, Mary E, Jarvinen, Gordon D, Schulte, Louis D, Stark, Peter C, Chamberlin, Rebecca M, Abney, Kent D, Ricketts, Thomas E, Valdez, Yvette E, and Bartsch, Richard A. Wed . "Americium separations from high salt solutions". United States. https://doi.org/10.2172/753372. https://www.osti.gov/servlets/purl/753372.
@article{osti_753372,
title = {Americium separations from high salt solutions},
author = {Barr, Mary E and Jarvinen, Gordon D and Schulte, Louis D and Stark, Peter C and Chamberlin, Rebecca M and Abney, Kent D and Ricketts, Thomas E and Valdez, Yvette E and Bartsch, Richard A},
abstractNote = {Americium (III) exhibits an unexpectedly high affinity for anion-exchange material from the high-salt evaporator bottoms solutions--an effect which has not been duplicated using simple salt solutions. Similar behavior is observed for its lanthanide homologue, Nd(III), in complex evaporator bottoms surrogate solutions. There appears to be no single controlling factor--acid concentration, total nitrate concentration or solution ionic strength--which accounts for the approximately 2-fold increase in retention of the trivalent ions from complex solutions relative to simple solutions. Calculation of species activities (i.e., water, proton and nitrate) in such concentrated mixed salt solutions is difficult and of questionable accuracy, but it is likely that the answer to forcing formation of anionic nitrate complexes of americium lies in the relative activities of water and nitrate. From a practical viewpoint, the modest americium removal needs (ca. 50--75%) from nitric acid evaporator bottoms allow sufficient latitude for the use of non-optimized conditions such as running existing columns filled with older, well-used Reillex HPQ. Newer materials, such as HPQ-100 and the experimental bifunctional resins, which exhibit higher distribution coefficients, would allow for either increased Am removal or the use of smaller columns. It is also of interest that one of the experimental neutral-donor solid-support extractants, DHDECMP, exhibits a similarly high level of americium (total alpha) removal from EV bottoms and is much less sensitive to total acid content than commercially-available material.},
doi = {10.2172/753372},
url = {https://www.osti.gov/biblio/753372}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {3}
}