Alteration and dissolution of Na-montmorillonite in simulated groundwaters

Emmi Myllykylä, Merja Tanhua-Tyrkkö, A. Bouchet

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    1 Citation (Scopus)


    This study aims at gaining a better understanding of the behaviour of montmorillonite in contact with different ground waters; alteration of montmorillonite and possible formation of secondary minerals. Batch experiments were conducted with purified Swy-2 montmorillonite in simulated fresh (I=0.05 M, pH 8) and saline (I=0.1 M, pH 11) waters at 25 and 60°C in anaerobic (Ar(g)) conditions. The concentrations of Al, Fe; Mg and Si were analysed from ultra-filtered solution samples with HR-ICP-MS (High Resolution Inductively Coupled Plasma Mass Spectrometry). The amount of released Si depended strongly on the experimental conditions. The Si concentrations at 60°C in the saline and fresh waters showed a difference greater than an order of magnitude. The initial purified montmorillonite and the solid materials from experiments were analysed with XRD. The analysis indicated that the nature of smectite did not change, but the experimental conditions, more or less, modified the structure of montmorillonite, e.g., in fresh waters the XRD spectra showed peaks typical of mixed layer minerals, which can refer to the presence of either randomly ordered illite/smectite or randomly ordered collapsed smectite/hydrated smectite layers. The dissolution of montmorillonite was studied also by modelling with TOUGHREACT. The experimental and modelled results were compared revealing a need to develop the model e.g. in respect of the evolution of pH.
    Original languageEnglish
    Title of host publicationMRS Proceedings
    Subtitle of host publicationSymposium NW – Scientific Basis for Nuclear Waste Management XXXV
    PublisherMaterials Research Society
    ISBN (Print)978-1-6274-8264-6
    Publication statusPublished - 2012
    MoE publication typeA4 Article in a conference publication
    Event2012 MRS Spring Meeting - San Francisco, CA, United States
    Duration: 9 Apr 201213 Apr 2012

    Publication series

    SeriesMaterials Research Society Symposia Proceedings


    Conference2012 MRS Spring Meeting
    Country/TerritoryUnited States
    CitySan Francisco, CA


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