The extraction of cesium and strontium from acidic high activity nuclear waste using a purex process compatible organic extractant
TL;DR: In this article, a macrocyclic polyether (crown compound) was developed for each element to extract either alkali metals or alkaline earths from the synthetic mixed fission product solution.
Abstract: Purex process compatible organic systems which selectively and reversibly extract cesium and strontium from synthetic mixed fission product solutions containing3M HNO3, have been developed. This advance makes the development of continuous solvent extraction processes for their recovery more likely. The matrix solution from the Purex process consists of tributyl phosphate (TBP) and kerosene. For cesium and strontium recovery a macrocyclic polyether (crown compound) has been developed for each element. When used in conjunction with a liquid cation exchanger in the matrix solution, the crown compounds will extract either alkali metals or alkaline earths from the synthetic mixed fission product solution. The organic cation exchangers used in this research were didodecylnaphthalene sulfonic acid (DNS) and dinonylnaphthalene sulfonic acid (NNS). As was expected both zirconium and ruthenium also tend to be extracted due to the TBP in the matrix solution and to their complex chemistry. The most favorable cesium a...
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TL;DR: In this paper, a new process for the extraction and recovery of strontium from acidic waste streams is described, called SREX (for Strontium Extraction), which extracts from acidic ( ≥ 1M HNO3) solution using a 0.20M solution of di-t-butylcyclohexano-18-crown-6 in 1-octanol.
Abstract: A new process for the extraction and recovery of strontium from acidic waste streams is described. In this process, called SREX (for Strontium Extraction), strontium is extracted from acidic ( ≥ 1 M HNO3) solution using a 0.20M solution of di-t-butylcyclohexano-18-crown-6 in 1-octanol. Extracted strontium is readily stripped from the organic phase using either water or dilute (<0.05 M) HNO3. Tests of the process on a synthetic dissolved sludge waste solution show that only strontium, barium, and technetium are appreciably extracted by the crown ether. Prolonged exposure of the process solvent to nitric acid at elevated temperatures or to ≤ 50 Wh/L γ radiation from a 60Co source produces essentially no deterioration in its performance. Benchtop batch countercurrent extraction experiments show that 99.7% of the strontium initially present in a feed solution can be removed in only three extraction stages.
261 citations
TL;DR: In this paper, the authors call out what is perceived to be a timely need for increased research to develop improved and new solvent extraction technology for recovery of 137Cs and 90Sr from strong (≥ 0.5M HNO3) acid media, technology which can be quickly scaled up to routine plant-scale operation with highly radioactive waste solutions when needed.
Abstract: A principal purpose of this paper is to call out what is perceived to be a timely need for increased research to develop improved and new solvent extraction technology for recovery of 137Cs and 90Sr from strong (≥ 0.5M HNO3) acid media, technology which can be quickly scaled up to routine plant-scale operation with highly radioactive waste solutions when needed. The present and forseeable future (2020) U.S. inventory of 137Cs and 90sr is listed; much of this inventory is expected to be available only in strongly acidic nuclear waste solutions. Comparison of available methods-precipitation and ion exchange as well as solvent extraction—for recovering 137 Cs and 90Sr from alkaline and acid media demonstrates, as expected, that very limited technology is available for use with strongly acidic solutions. Solvent extraction procedures which employ either macrocyclic polyethers (crown ethers) or dicarbolide. H+{[π-(3)-1, 2-B9C2H11Cl2±2Co}−, to extract 137Cs and 90Sr from ≥ 0.5M HNO3 solutions have rece...
203 citations
TL;DR: A comprehensive review of synergistic solvent extraction using crown ethers with a focus on the role of both extractants in facilitating cation-specific separations is provided in this article. But this review is limited to a single extractant.
Abstract: This paper provides a comprehensive review of synergistic solvent extraction using crown ethers with a focus on the role of both extractants in facilitating cation-specific separations. An introduction to the various equilibria affecting synergistic extraction using crown ethers is followed by a review of the work published in this field during the 1972-1999 time period. The influence of various solvent extraction parameters on the potential for cation-selective synergism is critically examined. Those synergistic extractant combinations showing cation selectivity are highlighted, as are the fundamental investigations that are the foundation of the current understanding of synergistic solvent extraction using crown ethers.
126 citations
TL;DR: In this paper, a series of lipophilic crown ether carboxylic acids with varying ring sizes was used for solvent extraction of alkali-metal cations from aqueous solutions into chlororform.
Abstract: Competitive solvent extraction of alkali-metal cations from aqueous solutions into chlororform by a series of lipophilic crown ether carboxylic acids with varying ring sizes is reported. Extraction selectivity for Li{sup +} is observed for lipophilic crown ether carboxylic acids with 12-15-membered polyether rings containing four oxygen atoms. For lipophilic 14-crown-4-carboxylic acids, very high Li{sup +}/Na{sup +} selectivity coefficients of 17-20 are observed with no detectable extraction of K{sup +}, Rb{sup +}, or Cs{sup +}. Lipophilic crown ether carboxylic acids which contain 15-crown-5, 18-crown-6, and 21-crown-7 rings exhibit good selectivities for Na{sup +}, K{sup +}, and Cs{sup +}, respectively. In contrast, poor extraction selectivity is observed for lipophilic crown ether carboxylic acids with 24-crown-8, 27-crown-9, and 30-crown-10 rings.
69 citations
TL;DR: In this paper, a new process for the extraction and recovery of strontium from acidic waste streams is described, which is a modification of the previously described SREX (For Strontium extraction) process, using a 0.2 M solution of di-t-butylcyclohexano-18-crown-6 in any of a variety of phase modifier / paraffinic hydrocarbon mixtures, among them a PUREX-like diluent comprised of a 1.2M solution of tri-nbutyl-phosphate in
Abstract: A new process for the extraction and recovery of strontium from acidic waste streams is described. In this process, a modification of the previously described SREX (for strontium extraction) process, strontium is extracted from acidic (≥ 2 M nitric acid) solution using a 0.2 M solution of di-t-butylcyclohexano-18-crown-6 in any of a variety of phase modifier / paraffinic hydrocarbon mixtures, among them a PUREX-like diluent comprised of a 1.2 M solution of tri-n-butyl-phosphate in Isopar L. Tests of this process solvent on a synthetic dissolved sludge waste show that only strontium and barium are appreciably extracted by the crown ether under the experimental conditions. As expected, uranium and plutonium are extracted even in the absence of the crown ether.
63 citations
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TL;DR: Cyclic polyethers have been successfully employed, inter alia, in experiments with ionic compounds in organic solvents and in studies of ion transport in biological systems.
Abstract: The most important, and almost unique, property of the macrocyclic polyethers (“crown compounds”) is their tendency to form complexes with alkali metal salts and salts with similar cations Such complexes are held together by electrostatic attraction between the cation and the negative end of the CO dipoles The stability of the polyether complexes depends primarily upon how well the cation fits into the polyether ring; other factors are the charge density of the cation and—in solution—the solvating power of the medium Cyclic polyethers have been successfully employed, inter alia, in experiments with ionic compounds in organic solvents and in studies of ion transport in biological systems
739 citations
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01 Apr 1981TL;DR: The branch of chemical engineering that deals with the production and use of radioisotopes, nuclear energy, and nuclear power is a branch of the Chemical Engineering Department of MIT.
Abstract: The branch of chemical engineering that deals with the production and use of radioisotopes, nuclear …
627 citations
TL;DR: In this article, the prominent lines of 70 elements as emitted in an inductively coupled plasma excitation source have been identified and the lines are listed alphabetically by element and numerically by wavelength.
Abstract: The prominent lines of 70 elements as emitted in an inductively coupled plasma excitation source have been identified. The lines are listed alphabetically by element and numerically by wavelength. Detection limit capabilities are estimated for each spectral line.
391 citations
311 citations
TL;DR: In this paper, a series of crown compounds were studied in connection with the development of a solvent extraction process for removing Cs+ and Srs2+ from acidic high activity nuclear waste.
Abstract: A series of crown compounds has been studied in connection with the development of a solvent extraction process for removing Cs+ and Srs2+ from acidic high activity nuclear waste. Crown compounds were investigated because of their ability to form organic soluble complexes with the alkali metals and the alkaline earth metals. The solvent (tributyl phosphate and kerosene) was chosen because of its compatibility with the Purex process currently used at the Savannah River Plant for plutonium and uranium purification. The crown compounds were found not to be sufficiently strong complexing agents to extract these metals from an aqueous phase with an inorganic anion such as nitrate or chloride. However, the use of large organic soluble anions which also functioned as liquid ion exchangers made it possible to extract Cs+ from 3 M HNO3 while leaving Sr2+ and La3+ behind. The use of .02 M bis-(4,4′(5′)-[q-hydroxyheptyl]-benzo)-18-crown-6 in 0.076 M (5 vol-%) didodecylnaphthalene sulfonic acid (DNS)-27 vol-...
67 citations