Thermodynamics and extraction modeling of trivalent lanthanides in the nuclear fuel cycle
- Pacific Northwest National Laboratory, 902 Battelle Blvd, PO Box 999, MSIN P7-25 Richland, WA 99352 (United States)
In this investigation, a combination of VPO (Vapor Pressure Osmometry) and water activity methods was applied to measure water activity and osmotic coefficients of binary lanthanide nitrate solutions at a temperature of 25 C. degrees. It was observed that the nature of the lanthanide nitrate has pronounced effect on the water activity in solution. In the solutions with the same Ln(NO{sub 3}){sub 3} molality, water activity is decreased in the order from the light to heavy lanthanides. This trend was explained by the contraction of the lanthanide ionic radii in the same order resulting in the [Ln(H{sub 2}O){sub n}]{sup 3+} (aq) hydration number of 9 for the early (La-Sm) and 8 for the late (Dy-Lu) lanthanides, with the intermediate metals exhibiting a mixture of eight and nine coordinate molecules. This results in the dissimilar effect of the light and heavy lanthanides on the water structure manifesting in the systematic changes of the water activity in the series of concentrated lanthanide solutions. Experimental water activity and osmotic coefficient data agree well with the literature for both 1:1 and 3:1 electrolyte systems. The Pitzer parameters obtained fitting these data are in an excellent agreement with the literature reported values for Ln(NO{sub 3}){sub 3} solutions.
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 22264211
- Resource Relation:
- Conference: GLOBAL 2013: International Nuclear Fuel Cycle Conference - Nuclear Energy at a Crossroads, Salt Lake City, UT (United States), 29 Sep - 3 Oct 2013; Other Information: Country of input: France; 6 refs.; Related Information: In: Proceedings of GLOBAL 2013: International Nuclear Fuel Cycle Conference - Nuclear Energy at a Crossroads| 1633 p.
- Country of Publication:
- United States
- Language:
- English
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