Studies on the chemical conditions and microstructure in Package 1 of Alternative Buffer Materials project (ABM) in Äspö

Arto Muurinen

    Research output: Book/ReportReportProfessional

    Abstract

    The chemical and microstructural properties of MX-80, Asha and Deponit bentonites and of Friedland Clay in package 1 of the ABM project in Äspö HRL were studied after over two years of experiment. The concentration distribution of chloride and sulphate in different clays as a function of distance from the heater and in the reference bentonites, not used in the experiment, were determined. The concentration distributions of chloride were quite even. In Friedland clay and Asha the chloride concentrations in the clay decreased during the experiment while in MX-80 and Deponit the concentrations increased. Sulphate accumulated towards the hot end in the samples where the initial content of sulphate was high (Friedland Clay, MX-80, Deponit), while in Asha, where the initial sulphate concentration was low, such an accumulation did not occur.

    The cation exchange capacity in different clays was determined at different distances from the heater using the complex of copper(II) ion with trietylenetetramine [Cu(trien)]2+ as the index cation. The CEC of MX-80 and Deponit increased slightly close to the heater. In Asha there was some indication about the decrease of CEC close to the heater while in Friedland Clay there was small decreasing trend towards the heater and the CEC was generally slightly higher than in the reference sample.

    The pH measurements in the clays were performed with IrOx electrodes at a distance of 8 cm from the heater. The pH values were for Friedland Clay 6.5 – 6.6, for MX-80 6.6 – 6.8, for Asha 6.9 – 7.0 and for Deponit 6.6 – 6.9. The Eh measurements were performed with Pt and Au electrodes placed in the clays at 8 cm from the heater. The final values obtained after five months of measurement with Au and Pt electrodes were for Friedland Clay 17 mV and -231 mV, for MX-80 22 mV and -48 mV, for Asha 104 mV and 40 mV and for Deponit 76 mV and 75 mV, respectively.

    The water content and bulk density were measured at different distances from the heater; the dry density and water porosity were calculated on the basis of the water content and bulk density measurements. It was obvious that the wet and dry densities were somewhat lower and water porosity higher in the cooler parts of the samples. The microstructure of the wet samples of MX-80, Deponit and Asha blocks at distances of 1 to 3 cm and 7 to 9 cm from the heater were studied with XRD. The peak places of all the clays indicated that there are two to three water layers in the interlamellar space. The basal spaces of the peaks were smaller than the evaluated theoretical basal spaces in all the studied bentonites, indicating that not all the water was in the interlamellar space of well-organized montmorillonite. Small-angle X-ray Scattering (SAXS) measurements supported the results given by XRD. By comparing the water amount based on SAXS basal space measurements with the water amount in the bentonite sample measured by drying, it could be seen that the water amount, which is not seen by SAXS, is about 25 % of the total water when the dry density is 1.4 - 1.5 g/cm3.
    Original languageEnglish
    Place of PublicationEurajoki
    PublisherPosiva
    Number of pages39
    Publication statusPublished - 2010
    MoE publication typeD4 Published development or research report or study

    Publication series

    NameWorking report
    PublisherPosiva Oy
    No.2010-11

    Fingerprint

    microstructure
    clay
    cation exchange capacity
    dry density
    sulfate
    water
    electrode
    scattering
    chloride
    bulk density
    chemical
    project
    material
    water content
    porosity
    X-ray diffraction
    heater
    reference sample
    experiment
    bentonite

    Cite this

    Muurinen, Arto. / Studies on the chemical conditions and microstructure in Package 1 of Alternative Buffer Materials project (ABM) in Äspö. Eurajoki : Posiva , 2010. 39 p. (Working Report; No. 2010-11).
    @book{69c3209efcff4b2ab79d08469d8ad7b6,
    title = "Studies on the chemical conditions and microstructure in Package 1 of Alternative Buffer Materials project (ABM) in {\"A}sp{\"o}",
    abstract = "The chemical and microstructural properties of MX-80, Asha and Deponit bentonites and of Friedland Clay in package 1 of the ABM project in {\"A}sp{\"o} HRL were studied after over two years of experiment. The concentration distribution of chloride and sulphate in different clays as a function of distance from the heater and in the reference bentonites, not used in the experiment, were determined. The concentration distributions of chloride were quite even. In Friedland clay and Asha the chloride concentrations in the clay decreased during the experiment while in MX-80 and Deponit the concentrations increased. Sulphate accumulated towards the hot end in the samples where the initial content of sulphate was high (Friedland Clay, MX-80, Deponit), while in Asha, where the initial sulphate concentration was low, such an accumulation did not occur. The cation exchange capacity in different clays was determined at different distances from the heater using the complex of copper(II) ion with trietylenetetramine [Cu(trien)]2+ as the index cation. The CEC of MX-80 and Deponit increased slightly close to the heater. In Asha there was some indication about the decrease of CEC close to the heater while in Friedland Clay there was small decreasing trend towards the heater and the CEC was generally slightly higher than in the reference sample. The pH measurements in the clays were performed with IrOx electrodes at a distance of 8 cm from the heater. The pH values were for Friedland Clay 6.5 – 6.6, for MX-80 6.6 – 6.8, for Asha 6.9 – 7.0 and for Deponit 6.6 – 6.9. The Eh measurements were performed with Pt and Au electrodes placed in the clays at 8 cm from the heater. The final values obtained after five months of measurement with Au and Pt electrodes were for Friedland Clay 17 mV and -231 mV, for MX-80 22 mV and -48 mV, for Asha 104 mV and 40 mV and for Deponit 76 mV and 75 mV, respectively. The water content and bulk density were measured at different distances from the heater; the dry density and water porosity were calculated on the basis of the water content and bulk density measurements. It was obvious that the wet and dry densities were somewhat lower and water porosity higher in the cooler parts of the samples. The microstructure of the wet samples of MX-80, Deponit and Asha blocks at distances of 1 to 3 cm and 7 to 9 cm from the heater were studied with XRD. The peak places of all the clays indicated that there are two to three water layers in the interlamellar space. The basal spaces of the peaks were smaller than the evaluated theoretical basal spaces in all the studied bentonites, indicating that not all the water was in the interlamellar space of well-organized montmorillonite. Small-angle X-ray Scattering (SAXS) measurements supported the results given by XRD. By comparing the water amount based on SAXS basal space measurements with the water amount in the bentonite sample measured by drying, it could be seen that the water amount, which is not seen by SAXS, is about 25 {\%} of the total water when the dry density is 1.4 - 1.5 g/cm3.",
    author = "Arto Muurinen",
    year = "2010",
    language = "English",
    series = "Working report",
    publisher = "Posiva",
    number = "2010-11",
    address = "Finland",

    }

    Studies on the chemical conditions and microstructure in Package 1 of Alternative Buffer Materials project (ABM) in Äspö. / Muurinen, Arto.

    Eurajoki : Posiva , 2010. 39 p. (Working Report; No. 2010-11).

    Research output: Book/ReportReportProfessional

    TY - BOOK

    T1 - Studies on the chemical conditions and microstructure in Package 1 of Alternative Buffer Materials project (ABM) in Äspö

    AU - Muurinen, Arto

    PY - 2010

    Y1 - 2010

    N2 - The chemical and microstructural properties of MX-80, Asha and Deponit bentonites and of Friedland Clay in package 1 of the ABM project in Äspö HRL were studied after over two years of experiment. The concentration distribution of chloride and sulphate in different clays as a function of distance from the heater and in the reference bentonites, not used in the experiment, were determined. The concentration distributions of chloride were quite even. In Friedland clay and Asha the chloride concentrations in the clay decreased during the experiment while in MX-80 and Deponit the concentrations increased. Sulphate accumulated towards the hot end in the samples where the initial content of sulphate was high (Friedland Clay, MX-80, Deponit), while in Asha, where the initial sulphate concentration was low, such an accumulation did not occur. The cation exchange capacity in different clays was determined at different distances from the heater using the complex of copper(II) ion with trietylenetetramine [Cu(trien)]2+ as the index cation. The CEC of MX-80 and Deponit increased slightly close to the heater. In Asha there was some indication about the decrease of CEC close to the heater while in Friedland Clay there was small decreasing trend towards the heater and the CEC was generally slightly higher than in the reference sample. The pH measurements in the clays were performed with IrOx electrodes at a distance of 8 cm from the heater. The pH values were for Friedland Clay 6.5 – 6.6, for MX-80 6.6 – 6.8, for Asha 6.9 – 7.0 and for Deponit 6.6 – 6.9. The Eh measurements were performed with Pt and Au electrodes placed in the clays at 8 cm from the heater. The final values obtained after five months of measurement with Au and Pt electrodes were for Friedland Clay 17 mV and -231 mV, for MX-80 22 mV and -48 mV, for Asha 104 mV and 40 mV and for Deponit 76 mV and 75 mV, respectively. The water content and bulk density were measured at different distances from the heater; the dry density and water porosity were calculated on the basis of the water content and bulk density measurements. It was obvious that the wet and dry densities were somewhat lower and water porosity higher in the cooler parts of the samples. The microstructure of the wet samples of MX-80, Deponit and Asha blocks at distances of 1 to 3 cm and 7 to 9 cm from the heater were studied with XRD. The peak places of all the clays indicated that there are two to three water layers in the interlamellar space. The basal spaces of the peaks were smaller than the evaluated theoretical basal spaces in all the studied bentonites, indicating that not all the water was in the interlamellar space of well-organized montmorillonite. Small-angle X-ray Scattering (SAXS) measurements supported the results given by XRD. By comparing the water amount based on SAXS basal space measurements with the water amount in the bentonite sample measured by drying, it could be seen that the water amount, which is not seen by SAXS, is about 25 % of the total water when the dry density is 1.4 - 1.5 g/cm3.

    AB - The chemical and microstructural properties of MX-80, Asha and Deponit bentonites and of Friedland Clay in package 1 of the ABM project in Äspö HRL were studied after over two years of experiment. The concentration distribution of chloride and sulphate in different clays as a function of distance from the heater and in the reference bentonites, not used in the experiment, were determined. The concentration distributions of chloride were quite even. In Friedland clay and Asha the chloride concentrations in the clay decreased during the experiment while in MX-80 and Deponit the concentrations increased. Sulphate accumulated towards the hot end in the samples where the initial content of sulphate was high (Friedland Clay, MX-80, Deponit), while in Asha, where the initial sulphate concentration was low, such an accumulation did not occur. The cation exchange capacity in different clays was determined at different distances from the heater using the complex of copper(II) ion with trietylenetetramine [Cu(trien)]2+ as the index cation. The CEC of MX-80 and Deponit increased slightly close to the heater. In Asha there was some indication about the decrease of CEC close to the heater while in Friedland Clay there was small decreasing trend towards the heater and the CEC was generally slightly higher than in the reference sample. The pH measurements in the clays were performed with IrOx electrodes at a distance of 8 cm from the heater. The pH values were for Friedland Clay 6.5 – 6.6, for MX-80 6.6 – 6.8, for Asha 6.9 – 7.0 and for Deponit 6.6 – 6.9. The Eh measurements were performed with Pt and Au electrodes placed in the clays at 8 cm from the heater. The final values obtained after five months of measurement with Au and Pt electrodes were for Friedland Clay 17 mV and -231 mV, for MX-80 22 mV and -48 mV, for Asha 104 mV and 40 mV and for Deponit 76 mV and 75 mV, respectively. The water content and bulk density were measured at different distances from the heater; the dry density and water porosity were calculated on the basis of the water content and bulk density measurements. It was obvious that the wet and dry densities were somewhat lower and water porosity higher in the cooler parts of the samples. The microstructure of the wet samples of MX-80, Deponit and Asha blocks at distances of 1 to 3 cm and 7 to 9 cm from the heater were studied with XRD. The peak places of all the clays indicated that there are two to three water layers in the interlamellar space. The basal spaces of the peaks were smaller than the evaluated theoretical basal spaces in all the studied bentonites, indicating that not all the water was in the interlamellar space of well-organized montmorillonite. Small-angle X-ray Scattering (SAXS) measurements supported the results given by XRD. By comparing the water amount based on SAXS basal space measurements with the water amount in the bentonite sample measured by drying, it could be seen that the water amount, which is not seen by SAXS, is about 25 % of the total water when the dry density is 1.4 - 1.5 g/cm3.

    M3 - Report

    T3 - Working report

    BT - Studies on the chemical conditions and microstructure in Package 1 of Alternative Buffer Materials project (ABM) in Äspö

    PB - Posiva

    CY - Eurajoki

    ER -