The mechanism of cesium immobilization in densified silica-fume blended cement pastes
- Department of Physical Chemistry, NRCN, P.O. Box 9001, Beer-Sheva (Israel)
- Faculty of Civil and Environmental Engineering, Technion, Haifa (Israel)
The role of silica-fume agglomerates, found in densified silica-fume (DSF) pastes, in the immobilization mechanism of Cs ions was studied. Samples of cementitious pastes containing two different forms of silica fume - DSF and raw silica fume (RSF) - were prepared. Leaching experiments showed that both additives reduced the leachability of the metal ion, but the effect of the DSF paste was much stronger. Scanning Electron Microscopy, together with Differential Thermal Analysis, proved that no agglomerated particles were present in the RSF pastes and that the extent of pozzolanic reactivity was higher. We therefore believe that unreacted silica within the DSF agglomerates adsorbs Cs ions and consequently increases their immobilization. Furthermore, this work suggests that during the pozzolanic reaction, a hydrated rim develops around the agglomerate that acts as an additional diffusion barrier for the Cs ions, resulting in an increased efficiency of Cs immobilization.
- OSTI ID:
- 21130723
- Journal Information:
- Cement and Concrete Research, Vol. 38, Issue 5; Other Information: DOI: 10.1016/j.cemconres.2007.09.017; PII: S0008-8846(07)00232-3; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
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