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Na/Ca selectivity coefficients of montmorillonite in perchlorate solution at different temperatures

Published online by Cambridge University Press:  27 March 2012

Aku Itälä
Affiliation:
VTT Technical Research Centre of Finland, Otakaari 3 K, Espoo, FI-02044 VTT, Finland
Arto Muurinen
Affiliation:
VTT Technical Research Centre of Finland, Otakaari 3 K, Espoo, FI-02044 VTT, Finland
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Abstract

The Finnish spent nuclear fuel disposal is based on the Swedish KBS-3 concept in crystalline bedrock. The concept aims at long-term isolation and containment of spent fuel in copper canisters surrounded by bentonite buffer which mostly consists of montmorillonite. For the long-term modelling of the chemical processes in the buffer, the cation-exchange selectivity coefficients have to be known at different temperatures. In this work, the cation-exchange selectivity coefficients and cation-exchange isotherms were determined in batch experiments for montmorillonite at three different temperatures (25 °C, 50 °C and 75 °C). Five different ratios of NaClO4/Ca(ClO4)2 were used in the experimental solutions. After equilibration the solution and montmorillonite were separated and the solution analysed to get the desired exchange parameters. The experiments were modelled with a computational model capable of taking into account the physicochemical processes that take place in the experiment.

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Articles
Copyright
Copyright © Materials Research Society 2012

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