Influence of alkaline (pH 8.3-12.0) and saline solutions on chemical, mineralogical and physical properties of two different bentonites

Tiina Heikola (Corresponding Author), S. Kumpulainen, Ulla Vuorinen, L. Kiviranta, P. Korkeakoski

    Research output: Contribution to journalArticleScientificpeer-review

    6 Citations (Scopus)

    Abstract

    The interaction of two different bulk bentonites (Na- and Ca-types) with three types of simulated cement waters (pH 9.7, 11.3 and 12.0) and one saline groundwater simulate (pH 8.3) as a reference, was studied in batch reactors at 25°C. The solution pH was monitored in order to keep the pH as steady as possible by replacing the leaching solution with fresh one when needed. After 554 days, one set of parallel samples was removed from the experiment in order to investigate the possible changes in the bentonite materials.

    The buffering capacity of bentonite was clearly observed, especially at the beginning of the high-pH experiments, as the pH of the leaching solutions decreased quite dramatically due to interaction with bentonite. The solution chemistry results showed a decrease of Ca content in all leachate samples, but especially in pH 12.0 experiments. Small amounts of silica were released throughout the experiment. Both bentonites in pH 12.0 experiments also released detectable amounts of Al, while in the lower pH experiments the levels were below detection limit. These observations were also supported by chemical analyses of the bentonite materials. Only minor changes were detected in the mineralogy, and they were mainly concentrated on experiments at pH 11.3 and pH 12.0. The measured swelling pressure showed an increase in pH 12.0 experiments. The results obtained in this research may facilitate modelling of bentonite interaction with high-pH solutions.
    Original languageEnglish
    Pages (from-to)309-329
    Number of pages20
    JournalClay Minerals
    Volume48
    Issue number2
    DOIs
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Sodium Chloride
    Chemical properties
    chemical property
    Bentonite
    Physical properties
    physical property
    bentonite
    experiment
    Experiments
    Leaching
    leaching
    Mineralogy
    Batch reactors
    buffering
    Silicon Dioxide
    swelling
    leachate
    Swelling
    Groundwater
    Cements

    Keywords

    • alkaline
    • alteration
    • batch
    • bentonite
    • bentonite buffer
    • saline spent nuclear fuel
    • underground repository

    Cite this

    Heikola, Tiina ; Kumpulainen, S. ; Vuorinen, Ulla ; Kiviranta, L. ; Korkeakoski, P. / Influence of alkaline (pH 8.3-12.0) and saline solutions on chemical, mineralogical and physical properties of two different bentonites. In: Clay Minerals. 2013 ; Vol. 48, No. 2. pp. 309-329.
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    abstract = "The interaction of two different bulk bentonites (Na- and Ca-types) with three types of simulated cement waters (pH 9.7, 11.3 and 12.0) and one saline groundwater simulate (pH 8.3) as a reference, was studied in batch reactors at 25°C. The solution pH was monitored in order to keep the pH as steady as possible by replacing the leaching solution with fresh one when needed. After 554 days, one set of parallel samples was removed from the experiment in order to investigate the possible changes in the bentonite materials.The buffering capacity of bentonite was clearly observed, especially at the beginning of the high-pH experiments, as the pH of the leaching solutions decreased quite dramatically due to interaction with bentonite. The solution chemistry results showed a decrease of Ca content in all leachate samples, but especially in pH 12.0 experiments. Small amounts of silica were released throughout the experiment. Both bentonites in pH 12.0 experiments also released detectable amounts of Al, while in the lower pH experiments the levels were below detection limit. These observations were also supported by chemical analyses of the bentonite materials. Only minor changes were detected in the mineralogy, and they were mainly concentrated on experiments at pH 11.3 and pH 12.0. The measured swelling pressure showed an increase in pH 12.0 experiments. The results obtained in this research may facilitate modelling of bentonite interaction with high-pH solutions.",
    keywords = "alkaline, alteration, batch, bentonite, bentonite buffer, saline spent nuclear fuel, underground repository",
    author = "Tiina Heikola and S. Kumpulainen and Ulla Vuorinen and L. Kiviranta and P. Korkeakoski",
    year = "2013",
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    language = "English",
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    Influence of alkaline (pH 8.3-12.0) and saline solutions on chemical, mineralogical and physical properties of two different bentonites. / Heikola, Tiina (Corresponding Author); Kumpulainen, S.; Vuorinen, Ulla; Kiviranta, L.; Korkeakoski, P.

    In: Clay Minerals, Vol. 48, No. 2, 2013, p. 309-329.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Influence of alkaline (pH 8.3-12.0) and saline solutions on chemical, mineralogical and physical properties of two different bentonites

    AU - Heikola, Tiina

    AU - Kumpulainen, S.

    AU - Vuorinen, Ulla

    AU - Kiviranta, L.

    AU - Korkeakoski, P.

    PY - 2013

    Y1 - 2013

    N2 - The interaction of two different bulk bentonites (Na- and Ca-types) with three types of simulated cement waters (pH 9.7, 11.3 and 12.0) and one saline groundwater simulate (pH 8.3) as a reference, was studied in batch reactors at 25°C. The solution pH was monitored in order to keep the pH as steady as possible by replacing the leaching solution with fresh one when needed. After 554 days, one set of parallel samples was removed from the experiment in order to investigate the possible changes in the bentonite materials.The buffering capacity of bentonite was clearly observed, especially at the beginning of the high-pH experiments, as the pH of the leaching solutions decreased quite dramatically due to interaction with bentonite. The solution chemistry results showed a decrease of Ca content in all leachate samples, but especially in pH 12.0 experiments. Small amounts of silica were released throughout the experiment. Both bentonites in pH 12.0 experiments also released detectable amounts of Al, while in the lower pH experiments the levels were below detection limit. These observations were also supported by chemical analyses of the bentonite materials. Only minor changes were detected in the mineralogy, and they were mainly concentrated on experiments at pH 11.3 and pH 12.0. The measured swelling pressure showed an increase in pH 12.0 experiments. The results obtained in this research may facilitate modelling of bentonite interaction with high-pH solutions.

    AB - The interaction of two different bulk bentonites (Na- and Ca-types) with three types of simulated cement waters (pH 9.7, 11.3 and 12.0) and one saline groundwater simulate (pH 8.3) as a reference, was studied in batch reactors at 25°C. The solution pH was monitored in order to keep the pH as steady as possible by replacing the leaching solution with fresh one when needed. After 554 days, one set of parallel samples was removed from the experiment in order to investigate the possible changes in the bentonite materials.The buffering capacity of bentonite was clearly observed, especially at the beginning of the high-pH experiments, as the pH of the leaching solutions decreased quite dramatically due to interaction with bentonite. The solution chemistry results showed a decrease of Ca content in all leachate samples, but especially in pH 12.0 experiments. Small amounts of silica were released throughout the experiment. Both bentonites in pH 12.0 experiments also released detectable amounts of Al, while in the lower pH experiments the levels were below detection limit. These observations were also supported by chemical analyses of the bentonite materials. Only minor changes were detected in the mineralogy, and they were mainly concentrated on experiments at pH 11.3 and pH 12.0. The measured swelling pressure showed an increase in pH 12.0 experiments. The results obtained in this research may facilitate modelling of bentonite interaction with high-pH solutions.

    KW - alkaline

    KW - alteration

    KW - batch

    KW - bentonite

    KW - bentonite buffer

    KW - saline spent nuclear fuel

    KW - underground repository

    U2 - 10.1180/claymin.2013.048.2.12

    DO - 10.1180/claymin.2013.048.2.12

    M3 - Article

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    EP - 329

    JO - Clay Minerals

    JF - Clay Minerals

    SN - 0009-8558

    IS - 2

    ER -