Detoxification of Uranium in Soils and Groundwater Using Recycled ConcreteCX(s) Applied: B3.6Date: 04/05/2011Location(s): Aiken, South CarolinaOffice(s): Environmental Management, Savannah River Operations Office
Office of NEPA Policy and Compliance
April 5, 2011
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CX(s) Applied: B3.6
Date: 04/05/2011
Location(s): Aiken, South Carolina
Office(s): Environmental Management, Savannah River Operations Office
Uranium (U) is the most frequently occurring radionuclide contaminant in soil and groundwater of the Department of Energy (DOE) complex, but current treatment options are either reversible or apply to only a limited set of conditions. This laboratory directed research and development effort seeks to demonstrate that U(VI) can be immobilized by inducing precipitation of U(VI) silicates by addition of powdered recycled concrete. Uranium silicates are stable over a wide range of pH and at the oxidizing conditions prevalent at most uranium waste sites. The predominant reactive component of cementitious material is the hydrated calcium silicate gel (C-S-H). If the reaction of C-S-H and U(VI) is sufficiently effective, then powdered clean concrete recycled from design and development operations could be used as the source of C-S-H, resulting in a very inexpensive amendment that would immobilize U in its oxidized form, insuring long-term treatment. The ability of Portland cement pastes to remove U(VI) from water solutions and to immobilize U(VI) in soils will be evaluated.