Interaction of fresh and saline waters with compacted bentonite

Arto Muurinen, Hannu Aalto, Torbjörn Carlsson, Jarmo Lehikoinen, Avner Melamed, Markus Olin, Pentti Salonen

    Research output: Book/ReportReport

    Abstract

    The interaction of compacted sodium bentonite with fresh groundwater simulant (Allard water) and saline groundwater was studied. The parameters varied in the experiments were water/bentonite ratio, the density of bentonite, composition of solution, temperature, and oxygen and carbon dioxide content in the surroundings. The main interest of the study were the chemical and mineralogical changes in solution and bentonite together with the microstructural properties of bentonite. The results presented in this interim report are preliminary and can change when the experiments are continued. The behaviour of individual cations presented a principal difference between the interactions with Allard water and saline water, while the differences caused by aerobic and anaerobic conditions were minor. The effect of the bentonite/water ratio was clear. The concentrations of the solutions changed more quickly when the b/w ratio was high and the obtained concentration levels, caused by dissolving accessory minerals, were higher, too. The major processes with Allard water were the diffusion of sodium, potassium, sulphate, bicarbonate and chloride from bentonite, and the diffusion of calcium and magnesium into bentonite. The density of bentonite affected the equilibrium state of the cations, which may be explained by changing cation exchange selectivity. The major processes in the experiments with saline water were the diffusion of sodium, magnesium, sulphate and bicarbonate from bentonite, and the diffusion of calcium into bentonite. The highest pH values were obtained in aerobic conditions both with saline and Allard water, intermediate values were obtained with Allard water in anaerobic conditions and the lowest values with saline anaerobic water. The copper tubes, which contained the bentonite during the experiments, also participated in the chemical reactions producing dissolved ions and precipitations in the solutions. The experimental equilibrium concentrations of the solution vs. b/w ratio and the values obtained by equilibrium model calculation were strikingly similar, although quantitative differences appeared. However, no definite conclusions regarding the validity of the bentonite model are to be made until more experimental data, especially at higher b/w ratios with special emphasis on pH, are available. The obtained surface areas by the BET-method and Hg porosimetry, about 20 m2/g, mean that each montmorillonite aggregate in bentonite would be formed on an average of 30 montmorillonite layers. In the freeze-dried sample about one third of the pores were smaller than 60 Å and not seen by the Hg porosimetry. The pore sizes seen in the SEM micrographs correspond qualitatively rather well with the results given by the Hg intrusion porosimetry.
    Original languageEnglish
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Number of pages45
    ISBN (Print)951-38-4869-8
    Publication statusPublished - 1995
    MoE publication typeNot Eligible

    Publication series

    SeriesVTT Tiedotteita - Meddelanden - Research Notes
    Number1714
    ISSN1235-0605

    Fingerprint

    bentonite
    water
    sodium
    oxic conditions
    bicarbonate
    montmorillonite
    anoxic conditions
    magnesium
    cation
    experiment
    calcium
    sulfate
    groundwater
    accessory mineral
    intermediate water
    chemical reaction
    ion exchange
    potassium
    surface area
    carbon dioxide

    Keywords

    • nuclear fuels
    • spent fuels
    • disposal
    • ground water
    • simulation
    • sodium
    • bentonite
    • fresh water
    • salt water
    • compacting
    • interactions
    • microstructure
    • mineralogy
    • experimentation

    Cite this

    Muurinen, A., Aalto, H., Carlsson, T., Lehikoinen, J., Melamed, A., Olin, M., & Salonen, P. (1995). Interaction of fresh and saline waters with compacted bentonite. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 1714
    Muurinen, Arto ; Aalto, Hannu ; Carlsson, Torbjörn ; Lehikoinen, Jarmo ; Melamed, Avner ; Olin, Markus ; Salonen, Pentti. / Interaction of fresh and saline waters with compacted bentonite. Espoo : VTT Technical Research Centre of Finland, 1995. 45 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1714).
    @book{55e842fce68b47d1b954b5ce2ffdf585,
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    abstract = "The interaction of compacted sodium bentonite with fresh groundwater simulant (Allard water) and saline groundwater was studied. The parameters varied in the experiments were water/bentonite ratio, the density of bentonite, composition of solution, temperature, and oxygen and carbon dioxide content in the surroundings. The main interest of the study were the chemical and mineralogical changes in solution and bentonite together with the microstructural properties of bentonite. The results presented in this interim report are preliminary and can change when the experiments are continued. The behaviour of individual cations presented a principal difference between the interactions with Allard water and saline water, while the differences caused by aerobic and anaerobic conditions were minor. The effect of the bentonite/water ratio was clear. The concentrations of the solutions changed more quickly when the b/w ratio was high and the obtained concentration levels, caused by dissolving accessory minerals, were higher, too. The major processes with Allard water were the diffusion of sodium, potassium, sulphate, bicarbonate and chloride from bentonite, and the diffusion of calcium and magnesium into bentonite. The density of bentonite affected the equilibrium state of the cations, which may be explained by changing cation exchange selectivity. The major processes in the experiments with saline water were the diffusion of sodium, magnesium, sulphate and bicarbonate from bentonite, and the diffusion of calcium into bentonite. The highest pH values were obtained in aerobic conditions both with saline and Allard water, intermediate values were obtained with Allard water in anaerobic conditions and the lowest values with saline anaerobic water. The copper tubes, which contained the bentonite during the experiments, also participated in the chemical reactions producing dissolved ions and precipitations in the solutions. The experimental equilibrium concentrations of the solution vs. b/w ratio and the values obtained by equilibrium model calculation were strikingly similar, although quantitative differences appeared. However, no definite conclusions regarding the validity of the bentonite model are to be made until more experimental data, especially at higher b/w ratios with special emphasis on pH, are available. The obtained surface areas by the BET-method and Hg porosimetry, about 20 m2/g, mean that each montmorillonite aggregate in bentonite would be formed on an average of 30 montmorillonite layers. In the freeze-dried sample about one third of the pores were smaller than 60 {\AA} and not seen by the Hg porosimetry. The pore sizes seen in the SEM micrographs correspond qualitatively rather well with the results given by the Hg intrusion porosimetry.",
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    Muurinen, A, Aalto, H, Carlsson, T, Lehikoinen, J, Melamed, A, Olin, M & Salonen, P 1995, Interaction of fresh and saline waters with compacted bentonite. VTT Tiedotteita - Meddelanden - Research Notes, no. 1714, VTT Technical Research Centre of Finland, Espoo.

    Interaction of fresh and saline waters with compacted bentonite. / Muurinen, Arto; Aalto, Hannu; Carlsson, Torbjörn; Lehikoinen, Jarmo; Melamed, Avner; Olin, Markus; Salonen, Pentti.

    Espoo : VTT Technical Research Centre of Finland, 1995. 45 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1714).

    Research output: Book/ReportReport

    TY - BOOK

    T1 - Interaction of fresh and saline waters with compacted bentonite

    AU - Muurinen, Arto

    AU - Aalto, Hannu

    AU - Carlsson, Torbjörn

    AU - Lehikoinen, Jarmo

    AU - Melamed, Avner

    AU - Olin, Markus

    AU - Salonen, Pentti

    PY - 1995

    Y1 - 1995

    N2 - The interaction of compacted sodium bentonite with fresh groundwater simulant (Allard water) and saline groundwater was studied. The parameters varied in the experiments were water/bentonite ratio, the density of bentonite, composition of solution, temperature, and oxygen and carbon dioxide content in the surroundings. The main interest of the study were the chemical and mineralogical changes in solution and bentonite together with the microstructural properties of bentonite. The results presented in this interim report are preliminary and can change when the experiments are continued. The behaviour of individual cations presented a principal difference between the interactions with Allard water and saline water, while the differences caused by aerobic and anaerobic conditions were minor. The effect of the bentonite/water ratio was clear. The concentrations of the solutions changed more quickly when the b/w ratio was high and the obtained concentration levels, caused by dissolving accessory minerals, were higher, too. The major processes with Allard water were the diffusion of sodium, potassium, sulphate, bicarbonate and chloride from bentonite, and the diffusion of calcium and magnesium into bentonite. The density of bentonite affected the equilibrium state of the cations, which may be explained by changing cation exchange selectivity. The major processes in the experiments with saline water were the diffusion of sodium, magnesium, sulphate and bicarbonate from bentonite, and the diffusion of calcium into bentonite. The highest pH values were obtained in aerobic conditions both with saline and Allard water, intermediate values were obtained with Allard water in anaerobic conditions and the lowest values with saline anaerobic water. The copper tubes, which contained the bentonite during the experiments, also participated in the chemical reactions producing dissolved ions and precipitations in the solutions. The experimental equilibrium concentrations of the solution vs. b/w ratio and the values obtained by equilibrium model calculation were strikingly similar, although quantitative differences appeared. However, no definite conclusions regarding the validity of the bentonite model are to be made until more experimental data, especially at higher b/w ratios with special emphasis on pH, are available. The obtained surface areas by the BET-method and Hg porosimetry, about 20 m2/g, mean that each montmorillonite aggregate in bentonite would be formed on an average of 30 montmorillonite layers. In the freeze-dried sample about one third of the pores were smaller than 60 Å and not seen by the Hg porosimetry. The pore sizes seen in the SEM micrographs correspond qualitatively rather well with the results given by the Hg intrusion porosimetry.

    AB - The interaction of compacted sodium bentonite with fresh groundwater simulant (Allard water) and saline groundwater was studied. The parameters varied in the experiments were water/bentonite ratio, the density of bentonite, composition of solution, temperature, and oxygen and carbon dioxide content in the surroundings. The main interest of the study were the chemical and mineralogical changes in solution and bentonite together with the microstructural properties of bentonite. The results presented in this interim report are preliminary and can change when the experiments are continued. The behaviour of individual cations presented a principal difference between the interactions with Allard water and saline water, while the differences caused by aerobic and anaerobic conditions were minor. The effect of the bentonite/water ratio was clear. The concentrations of the solutions changed more quickly when the b/w ratio was high and the obtained concentration levels, caused by dissolving accessory minerals, were higher, too. The major processes with Allard water were the diffusion of sodium, potassium, sulphate, bicarbonate and chloride from bentonite, and the diffusion of calcium and magnesium into bentonite. The density of bentonite affected the equilibrium state of the cations, which may be explained by changing cation exchange selectivity. The major processes in the experiments with saline water were the diffusion of sodium, magnesium, sulphate and bicarbonate from bentonite, and the diffusion of calcium into bentonite. The highest pH values were obtained in aerobic conditions both with saline and Allard water, intermediate values were obtained with Allard water in anaerobic conditions and the lowest values with saline anaerobic water. The copper tubes, which contained the bentonite during the experiments, also participated in the chemical reactions producing dissolved ions and precipitations in the solutions. The experimental equilibrium concentrations of the solution vs. b/w ratio and the values obtained by equilibrium model calculation were strikingly similar, although quantitative differences appeared. However, no definite conclusions regarding the validity of the bentonite model are to be made until more experimental data, especially at higher b/w ratios with special emphasis on pH, are available. The obtained surface areas by the BET-method and Hg porosimetry, about 20 m2/g, mean that each montmorillonite aggregate in bentonite would be formed on an average of 30 montmorillonite layers. In the freeze-dried sample about one third of the pores were smaller than 60 Å and not seen by the Hg porosimetry. The pore sizes seen in the SEM micrographs correspond qualitatively rather well with the results given by the Hg intrusion porosimetry.

    KW - nuclear fuels

    KW - spent fuels

    KW - disposal

    KW - ground water

    KW - simulation

    KW - sodium

    KW - bentonite

    KW - fresh water

    KW - salt water

    KW - compacting

    KW - interactions

    KW - microstructure

    KW - mineralogy

    KW - experimentation

    M3 - Report

    SN - 951-38-4869-8

    T3 - VTT Tiedotteita - Meddelanden - Research Notes

    BT - Interaction of fresh and saline waters with compacted bentonite

    PB - VTT Technical Research Centre of Finland

    CY - Espoo

    ER -

    Muurinen A, Aalto H, Carlsson T, Lehikoinen J, Melamed A, Olin M et al. Interaction of fresh and saline waters with compacted bentonite. Espoo: VTT Technical Research Centre of Finland, 1995. 45 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1714).