Quality Assurance of the Bentonite Material

Lasse Ahonen, Petri Korkeakoski, Mia Tiljander, Harri Kivikoski, Rainer Laaksonen

    Research output: Book/ReportReport

    Abstract

    This report describes a quality assurance chain for the bentonite material acquisition for a nuclear waste disposal repository. Chemical, mineralogical and geotechnical methods, which may be applied in quality control of bentonite are shortly reviewed. As a case study, many of the presented control studies were performed for six different bentonite samples, including Wyoming bentonite "MX-80" and three Indian bentonites (Kutch, Ashapura). Chemical analysis is a very reliable research method to control material homogeneity, because the accuracy and repeatability of the study method is extremely good. Accurate mineralogical study of bentonite is a complicated task. X-ray diffractometry is the best method to identify smectite minerals, but quantitative analysis of smectite content remains uncertain. To obtain a better quantitative analysis, development of techniques based on automatic image analysis of SEM images is proposed. General characteristics of bentonite can be obtained by rapid indicator tests, which can be done on the place of reception. These tests are methylene blue test giving information on the cation exchange capacity, swelling index and determination of water absorption. Different methods were used in the determination of cation exchange capacity (CEC) of bentonite. The results indicated differencies both between methodologies and between replicate determinations for the same material and method. Additional work should be done to improve the reliability and reproducibility of the methodology. Bentonite contains water in different modes. Thus, different determination methods are used in bentonite studies and they give somewhat dissimilar results. Clay research use frequently the so-called consistency tests (liquid limit, plastic limit and plasticity index). This study method does, however, not seem to be very practical in quality control of bentonite. Therefore only determination of liquid limit with fall-cone method is recommended for quality control.
    Original languageEnglish
    PublisherPosiva
    Number of pages122
    Publication statusPublished - 2008
    MoE publication typeD4 Published development or research report or study

    Publication series

    SeriesPosiva Working Report
    Number2008-33

    Fingerprint

    bentonite
    quality control
    study method
    liquid limit
    cation exchange capacity
    smectite
    quantitative analysis
    quality assurance
    material
    general characteristics
    methodology
    research method
    repository
    waste disposal
    image analysis
    radioactive waste
    chemical analysis
    swelling
    homogeneity
    plasticity

    Keywords

    • bentonite
    • chemical composition
    • clay mineralogy
    • X-ray diffractometry
    • cation exchange capacity
    • thermal analysis
    • swelling index
    • quality assurance system

    Cite this

    Ahonen, L., Korkeakoski, P., Tiljander, M., Kivikoski, H., & Laaksonen, R. (2008). Quality Assurance of the Bentonite Material. Posiva. Posiva Working Report, No. 2008-33
    Ahonen, Lasse ; Korkeakoski, Petri ; Tiljander, Mia ; Kivikoski, Harri ; Laaksonen, Rainer. / Quality Assurance of the Bentonite Material. Posiva, 2008. 122 p. (Posiva Working Report; No. 2008-33).
    @book{0225edcee6ed4c29bf502e508bbd06c5,
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    Ahonen, L, Korkeakoski, P, Tiljander, M, Kivikoski, H & Laaksonen, R 2008, Quality Assurance of the Bentonite Material. Posiva Working Report, no. 2008-33, Posiva.

    Quality Assurance of the Bentonite Material. / Ahonen, Lasse; Korkeakoski, Petri; Tiljander, Mia; Kivikoski, Harri; Laaksonen, Rainer.

    Posiva, 2008. 122 p. (Posiva Working Report; No. 2008-33).

    Research output: Book/ReportReport

    TY - BOOK

    T1 - Quality Assurance of the Bentonite Material

    AU - Ahonen, Lasse

    AU - Korkeakoski, Petri

    AU - Tiljander, Mia

    AU - Kivikoski, Harri

    AU - Laaksonen, Rainer

    PY - 2008

    Y1 - 2008

    N2 - This report describes a quality assurance chain for the bentonite material acquisition for a nuclear waste disposal repository. Chemical, mineralogical and geotechnical methods, which may be applied in quality control of bentonite are shortly reviewed. As a case study, many of the presented control studies were performed for six different bentonite samples, including Wyoming bentonite "MX-80" and three Indian bentonites (Kutch, Ashapura). Chemical analysis is a very reliable research method to control material homogeneity, because the accuracy and repeatability of the study method is extremely good. Accurate mineralogical study of bentonite is a complicated task. X-ray diffractometry is the best method to identify smectite minerals, but quantitative analysis of smectite content remains uncertain. To obtain a better quantitative analysis, development of techniques based on automatic image analysis of SEM images is proposed. General characteristics of bentonite can be obtained by rapid indicator tests, which can be done on the place of reception. These tests are methylene blue test giving information on the cation exchange capacity, swelling index and determination of water absorption. Different methods were used in the determination of cation exchange capacity (CEC) of bentonite. The results indicated differencies both between methodologies and between replicate determinations for the same material and method. Additional work should be done to improve the reliability and reproducibility of the methodology. Bentonite contains water in different modes. Thus, different determination methods are used in bentonite studies and they give somewhat dissimilar results. Clay research use frequently the so-called consistency tests (liquid limit, plastic limit and plasticity index). This study method does, however, not seem to be very practical in quality control of bentonite. Therefore only determination of liquid limit with fall-cone method is recommended for quality control.

    AB - This report describes a quality assurance chain for the bentonite material acquisition for a nuclear waste disposal repository. Chemical, mineralogical and geotechnical methods, which may be applied in quality control of bentonite are shortly reviewed. As a case study, many of the presented control studies were performed for six different bentonite samples, including Wyoming bentonite "MX-80" and three Indian bentonites (Kutch, Ashapura). Chemical analysis is a very reliable research method to control material homogeneity, because the accuracy and repeatability of the study method is extremely good. Accurate mineralogical study of bentonite is a complicated task. X-ray diffractometry is the best method to identify smectite minerals, but quantitative analysis of smectite content remains uncertain. To obtain a better quantitative analysis, development of techniques based on automatic image analysis of SEM images is proposed. General characteristics of bentonite can be obtained by rapid indicator tests, which can be done on the place of reception. These tests are methylene blue test giving information on the cation exchange capacity, swelling index and determination of water absorption. Different methods were used in the determination of cation exchange capacity (CEC) of bentonite. The results indicated differencies both between methodologies and between replicate determinations for the same material and method. Additional work should be done to improve the reliability and reproducibility of the methodology. Bentonite contains water in different modes. Thus, different determination methods are used in bentonite studies and they give somewhat dissimilar results. Clay research use frequently the so-called consistency tests (liquid limit, plastic limit and plasticity index). This study method does, however, not seem to be very practical in quality control of bentonite. Therefore only determination of liquid limit with fall-cone method is recommended for quality control.

    KW - bentonite

    KW - chemical composition

    KW - clay mineralogy

    KW - X-ray diffractometry

    KW - cation exchange capacity

    KW - thermal analysis

    KW - swelling index

    KW - quality assurance system

    M3 - Report

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    BT - Quality Assurance of the Bentonite Material

    PB - Posiva

    ER -

    Ahonen L, Korkeakoski P, Tiljander M, Kivikoski H, Laaksonen R. Quality Assurance of the Bentonite Material. Posiva, 2008. 122 p. (Posiva Working Report; No. 2008-33).