Journal article
Cancrinite and sodalite formation in the presence of cesium, potassium, magnesium, calcium and strontium in Hanford tank waste simulants
Applied geochemistry, Vol.21(12), pp.2049-2063
2006
Handle:
https://hdl.handle.net/2376/112973
Abstract
High-level radioactive tank waste solutions that have leaked into the subsurface at the US Department of Energy Hanford Site, Washington, are chemically complex. Here, the effect of five cations, Cs
+, K
+, Sr
2+, Ca
2+ and Mg
2+, on mineral formation and transformation pathways under conditions mimicking Hanford tank leaks is investigated. Sodium silicate was used to represent the dissolved silicate from sediments. The silicate was added into a series of simulants that contained 0.5
M aluminate, 1
M or 16
M NaOH, and the
NO
3
-
salts of the cations. The precipitates were monitored by X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectroscopy. In the 1
M NaOH simulants, low concentration of Cs
+ (<100
mM) did not affect the formation of lepispheric cancrinite and sodalite, whereas only highly crystalline cancrinite formed when Cs
+ concentration was ⩾250
mM. An unidentified feldspathoid or zeolite intermediate phase was observed in the presence of high concentrations of Cs
+ (500
mM). The presence of K
+ did not alter, but slowed, the formation of cancrinite and sodalite. The presence of divalent cations led to the formation of metastable or stable silicates, aluminates, hydroxides, or aluminosilicates. The formation of these intermediate phases slowed the formation of cancrinite and sodalite by consuming OH
−, silicate, or aluminate. Compared with the concentrations used in this study, the concentrations of radioactive Cs
+ and Sr
2+ in the tank solutions are much lower and divalent cations (Ca
2+ and Mg
2+) released from sediments likely precipitate out as hydroxides, silicates or aluminates; therefore, the authors do not expect that the presence of these monovalent and divalent cations significantly affect the formation of cancrinite and sodalite in the sediments underneath the leaking waste tanks.
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Details
- Title
- Cancrinite and sodalite formation in the presence of cesium, potassium, magnesium, calcium and strontium in Hanford tank waste simulants
- Creators
- Youjun Deng - Department of Crop and Soil Sciences, Center for Multiphase Environmental Research, Washington State University, Pullman, WA 99164-6420, United StatesMarkus Flury - Department of Crop and Soil Sciences, Center for Multiphase Environmental Research, Washington State University, Pullman, WA 99164-6420, United StatesJames B Harsh - Department of Crop and Soil Sciences, Center for Multiphase Environmental Research, Washington State University, Pullman, WA 99164-6420, United StatesAndrew R Felmy - Pacific Northwest National Laboratory, Environmental Molecular Science laboratory, Richland, WA 99352, United StatesOdeta Qafoku - Pacific Northwest National Laboratory, Environmental Molecular Science laboratory, Richland, WA 99352, United States
- Publication Details
- Applied geochemistry, Vol.21(12), pp.2049-2063
- Academic Unit
- Crop and Soil Sciences, Department of
- Publisher
- Elsevier Ltd
- Identifiers
- 99900548193001842
- Language
- English
- Resource Type
- Journal article