Extraction of Cs/sup +/ and Sr/sup 2 +/ from HNO/sub 3/ solution using macrocyclic polyethers
A series of crown compounds has been studied in connection with the development of a solvent extraction process for removing Cs/sup +/ and Sr/sup 2 +/ 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/sup +/ from 3 M HNO/sub 3/ while leaving Sr/sup 2 +/ and La/sup 3 +/ behind. The use of .02 M bis-(4,4'(5')-(1-hydroxyheptyl)-benzo)-18-crown-6 in 0.076 M (5 vol-%) didode-cylnaphthalene sulfonic acid (DNS)-27 vol-% TBP-68 vol-% kerosene gave the most favorable results for cesium extraction. The two phases separated cleanly and rapidly, yielding a distribution coefficient of 2.0 org/aq from 3 M HNO/sub 3/. Strontium and lanthanum did not extract significantly at this acid concentration. The distribution data in the low acid region (10/sup -4/ M) are best explained by steric hindrance effects. The lanthanum did not extract at any acid concentration while the strontium extracted very well by a liquid ion-exchange mechanism but the addition of the crown compound did not improve the distribution. The addition of the crown compound improved the Cs/sup +/ distribution markedly in the low acid region even though the Cs/sup +/ diameter is larger than the 18-crown-6-crown cavity while Sr/sup 2 +/ should fit very well.
- Research Organization:
- Univ. of South Carolina, Columbia
- DOE Contract Number:
- AS09-76ER00884
- OSTI ID:
- 6072741
- Journal Information:
- Sep. Sci. Technol.; (United States), Journal Name: Sep. Sci. Technol.; (United States) Vol. 16:5; ISSN SSTED
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400105* -- Separation Procedures
ALCOHOLS
ALKALI METALS
ALKALINE EARTH METALS
BUTYL PHOSPHATES
CESIUM
CHEMICAL ANALYSIS
DATA
ELEMENTS
ESTERS
EXPERIMENTAL DATA
EXTRACTION
FUELS
GLYCOLS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
INORGANIC ACIDS
KEROSENE
LANTHANUM
LIQUID FUELS
METALS
NITRIC ACID
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANIC POLYMERS
PETROLEUM PRODUCTS
PHOSPHORIC ACID ESTERS
POLYETHYLENE GLYCOLS
POLYMERS
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTHS
SEPARATION PROCESSES
SOLVENT EXTRACTION
SOLVENT PROPERTIES
STRONTIUM
TBP