Selective leaching of uranium from uranium-contaminated soils: Progress report 1

Francis, C.W.; Mattus, A.J.; Farr, L.L.; Elless, Mark P.; Lee, S.Y.

doi:10.2172/6529852

Cited by 16 publications

(13 citation statements)

References 3 publications

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“…Carbonate seems to be applicable for soil concentrations of uranium ranging from <450 to >50 mg/kg (ORNL 1993). The uranium recoveries seem to be insensitive to pH from 8-10 (Francis et al 1993). Alkaline leaching is generally considered to have slower kinetics relative to acid leaching systems.…”

Section: 5mentioning

confidence: 95%

Evaluation of Soil Flushing for Application to the Deep Vadose Zone in the Hanford Central Plateau

Truex¹,

Oostrom²,

Zhang³

et al. 2010

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Soil flushing was included in the Deep Vadose Zone Treatability Test Plan for the Hanford CentralPlateau (DOE-RL 2008 1 ) as a technology with the potential to remove contaminants from the vadose zone. Soil flushing operates through the addition of water, and if necessary an appropriate mobilizing agent, to mobilize contaminants and flush them from the vadose zone and into the groundwater where they are subsequently captured by a pump-and-treat system. There are uncertainties associated with applying soil flushing technology to contaminants in the deep vadose zone at the Hanford Central Plateau. The modeling and laboratory efforts reported herein are intended to provide a quantitative assessment of factors that impact water infiltration and contaminant flushing through the vadose zone and into the underlying groundwater. Once in the groundwater, capture of the contaminants would be necessary, but this aspect of implementing soil flushing was not evaluated in this effort. Soil flushing was evaluated primarily with respect to applications for technetium and uranium contaminants in the deep vadose zone of the Hanford Central Plateau. SummarySoil flushing operates through addition of water, and if necessary an appropriate mobilizing agent, to mobilize contaminants and flush them from the vadose zone and into the groundwater where they are subsequently captured by a pump-and-treat system. As described in the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (DOE-RL 2008), investigation of these vadose zone processes through modeling and laboratory evaluation is needed as a first step in providing information for considering soil flushing in subsequent feasibility studies for the Hanford Site deep vadose zone.Numerical modeling and laboratory flow-cell experiments were conducted to investigate the characteristics of water flow and solute transport through the vadose zone as a function of the imposed infiltration condition, subsurface properties, and properties of the leaching solution. Information on previous uranium leaching studies, infiltration studies at the Hanford Site data, and relevant uranium mining operations were compiled and evaluated with respect to how these approaches potentially apply to soil flushing in the Hanford Central Plateau.There are uncertainties associated with applying soil flushing technology to contaminants in the deep vadose zone at the Hanford Central Plateau. Modeling and laboratory efforts reported herein are intended to provide a quantitative assessment of factors that impact water infiltration and contaminant flushing through the vadose zone and into the underlying groundwater. Once in the groundwater, capture of the contaminants would be necessary, but this aspect of implementing soil flushing was not evaluated in this effort. Soil flushing was evaluated primarily with respect to applications for technetium and uranium contaminants in the deep vadose zone of the Hanford Central Plateau.Contaminants such as technetium do not interact significantly...

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Section: 5mentioning

confidence: 95%

Evaluation of Soil Flushing for Application to the Deep Vadose Zone in the Hanford Central Plateau

Truex¹,

Oostrom²,

Zhang³

et al. 2010

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“…The variation in distribution, solubility and particle size precluded the use a single washing reagent to remove the needed mass of uranium from the soil. For example, carbonate extractions removed approximately 60 to 85 percent of the uranium at circum-neutral pH, while citric acid/citrate removed 68 to 99 percent at pH 3 to 4 (Francis et al,1993). However, it is not cost effective to maintain a low pH in Fernald soils, as approximately 50 percent of the soil particles are carbonate grains.…”

Section: Previous Soil Washing Experience For Uranium (Fernald/mound)mentioning

confidence: 99%

“…The two Fernald soils used in these studies contained 387 and 470 mg U per kg of soil (Francis et al, 1993). Since the carbonate extraction is the only viable cost-effective approach for Fernald soils, the removal of only 60 percent of the uranium from the waste incinerator soil (470 mg/kg) resulted in a residual U concentration of 187 mg/kg, which was far above the final remediation level of 82 mg/kg.…”

Section: Previous Soil Washing Experience For Uranium (Fernald/mound)mentioning

confidence: 99%

“…Extensive characterization and leaching studies were carried out from 1992 through 1994 to evaluate soil washing at the Fernald site (Kneff et al, 1992;Lee and Marsh, 1992;Kneff et al, 1993;Schilk et al, 1993;Cunnane et al, 1993;Francis et al, 1993;Lee et al, 1993;DOE, 1993;Bertsch and Hunter, 1994;Buck et al, 1994;Mason et al, 1994;Turney et al, 1994). Results from these investigations identified four potential protocols for washing Fernald soil, and the costs associated with the protocols (Douthat et al, 1995a;1995b) exceed the soil washing costs in Table F In Table 1, the fixed capital investment (FCI) for the Fernald protocols is about 3 to 5 times greater than the estimate for Building 812; there is no start-up cost estimated for Building 812; and operational costs for Building 812 are at the lower end of the costs associated with the Fernald protocols.…”

Section: Cost Uncertaintymentioning

confidence: 99%

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Technical Evaluation of Soil Remediation Alternatives at the Building 812 Operable Unit, Lawrence Livermore National Laboratory Site 300

Eddy-Dilek¹,

Miles²,

Abitz³

2009

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“…The lixiviants used for uranium removal are similar to those used for soil washing and in the mining industry for uranium extraction; that is, they are electrolyte solutions containing carbonate ions (Francis et al 1995).…”

mentioning

confidence: 99%

Testing and evaluation of electrokinetic decontamination of concrete

DePaoli¹,

Harris²,

Ally

1996

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Selective leaching of uranium from uranium-contaminated soils: Progress report 1

Cited by 16 publications

References 3 publications

Evaluation of Soil Flushing for Application to the Deep Vadose Zone in the Hanford Central Plateau

Evaluation of Soil Flushing for Application to the Deep Vadose Zone in the Hanford Central Plateau

Technical Evaluation of Soil Remediation Alternatives at the Building 812 Operable Unit, Lawrence Livermore National Laboratory Site 300

Testing and evaluation of electrokinetic decontamination of concrete

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