Alkaline diffusion in compacted bentonite: Experiments and modeling
Cement-bentonite interaction will occur in deep geological repositories for radioactive waste.The diffusion processes and mineralogical transformations produced by alkaline fluids in a compacted bentonite column are studied. A hyper-alkaline solution (K-Na-OH, pH =13.5, 60 ℃) represents the degrading concrete in a repository over a short timescale (100s of years) and a Ca(OH)2 saturated solution (pH=12.5) represents the control maintained by an evolved concrete over a long timescale (1000s of years). Results with bentonite from after 6 months. Alkaline cations have diffused beyond this mineralogical alteration zone, and are exchanged by Mg2 + in the interlayer region of smectites, but no K-silicates have formed. The absence of zeolites in the alteration assemblage was not expected. Reactive transport simulations are able to reconcile main characteristics of the evolution of the alkaline front.
R.Fernández U.M(a)der L.Sánchez R.Vigil de la Villa J.Cuevas
Rock- Water Interaction group, Institute of Geological Sciences, University of Bern, Switzerland Department of Geology and Geochemistry, University Autónoma of Madrid, Spain
国际会议
第十二届水-岩相互作用国际研讨会(P0roceedings of the 12th International Symposium on Water-Rock Interaction)
昆明
英文
305-308
2007-07-31（万方平台首次上网日期，不代表论文的发表时间）