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
T3 - Posiva Working Report
BT - Quality Assurance of the Bentonite Material
PB - Posiva
ER -