Universal Solent Extraction (UNEX) Flowsheet Testing of the Removal of Cesium, Strontium, and Actinide Elements from Radioactive, Acidic Dissolved Calcine Waste
The presence of long-lived radionuclides presents a challenge to the management of radioactive wastes. Separation of the radionuclides from the waste solutions has the potential of significantly decreasing the costs associated with the immobilization and disposal of the radioactive waste by minimizing waste volumes. Typically, several separate processes are required for the separation of cesium, strontium, and actinides from radioactive wastes. A novel solvent extraction process, the Universal Extraction (UNEX) process, has been developed for the simultaneous separation of cesium, strontium, and the actinides from radioactive acidic waste solutions. The UNEX process solvent consists of chlorinated cobalt dicarbollide for the extraction of exp 137 Cs, polyethylene glycol for the extraction of exp 90 Sr, and diphenyl-N,N-di-n-butylcarbamoylmethyl phosphine oxide for the extraction of the actinides and lanthanides. A non-nitroaromatic polar diluent, phenyltrifluoromethyl sulfone, is used for this process. A UNEX flowsheet consisting of a single solvent extraction cycle has been developed as a part of a collaborative effort between the Khlopin Radium Institute (KRI) and the Idaho National Engineering and Environmental Laboratory (INEEL). This flowsheet has been demonstrated with actual dissolved radioactive calcine waste at the INEEL using 24 stages of 2-cm diameter centrifugal contactors installed in a shielded hot cell facility. For the major radionuclides, 99.99% of the exp 137 Cs, 99.73% of the exp 90 Sr, and > 99.9% of the actinides in the initial dissolved calcine feed were extracted and recovered in the high activity fraction. For the stable matrix elements, 12% of the Mo, 0.7% of the Zr, and 2% of the Fe were extracted and recovered in the strip product. The minor components Ba and Pb were quantitatively extracted and recovered in the strip product; 23% of the Mn was also present in this fraction. Very little Al, Ca, Cr, Na, and Ni were extracted into the UNEX solvent.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC07-99ID-13727
- OSTI ID:
- 912043
- Report Number(s):
- INEEL/JOU-01-01455; TRN: US0800271
- Journal Information:
- Solvent Extraction and Ion Exchange (USA), Vol. 20, Issue 4-5; ISSN 0736-6299
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACTINIDES
CESIUM
EXTRACTION APPARATUSES
FLOWSHEETS
HOT CELLS
LIQUID WASTES
MATRIX ELEMENTS
PHOSPHINE OXIDES
POLYETHYLENE GLYCOLS
RADIOACTIVE WASTES
RARE EARTHS
REMOVAL
SOLVENT EXTRACTION
SOLVENTS
STRONTIUM
TESTING
WASTES
Actinide metals
Cesium
Radioactive waste
Reactions (chemical)
Recovering
Solvent extraction
Strontium
Waste disposal