GEOC 52 |
| Bruce McNamara, Edgar C. Buck, and Brady Hanson. Environmental Technology Division, Radiochemical Processing, Pacific Norhwest Laboratory, PO Box 999, MS P7-25, Richland, WA 99352 |
| As UO2-based unirradiated fuels and commercial spent nuclear fuel (CSNF) are reacted with air and water, we have observed aggregates of the weathered UO2 suspended at the air-water interface. The aggregation phenomena were observed regardless of the UO2 alteration phase: schoepite, metaschoepite, dehydrated schoepite, or metastudtite. The long-term stability of the suspended films, and the aggregation mechanism are poorly understood. We show here that large particles of uranium oxide and the associated alteration phases are stabilized via electrostatic forces at the air-water interfaces, such as air bubbles. Additionally, changes in the solution pH will be shown to influence the formation and the fractal dimension of the aggregate structure. The further observation of films of freshly prepared hydrous ThO2, WO3, Mn (VI), Re(IV), Tc(IV) in aqueous solutions and at varied pH, indicates that such flotation is a common phenomenon for strictly inorganic materials. It is likely that different mechanisms account for the formation and stability of such films and their predilection toward flotation. |
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Colloid-Facilitated Transport of Contaminants in the Subsurface: The Life and Death of a Colloid
1:00 PM-5:20 PM, Monday, March 29, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |