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Diffusivities in Crystalline Rock Materials

Published online by Cambridge University Press:  28 February 2011

Kristina Skagius
Affiliation:
Department of Chemical Engineering, Royal Institute of Technology, S-100 44 Stockholm, Sweden
Ivars Neretnieks
Affiliation:
Department of Chemical Engineering, Royal Institute of Technology, S-100 44 Stockholm, Sweden
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Abstract

The diffusion of non-sorbing species in different crystalline rocks and fissure coating materials has been studied. The results show that the effective diffusivity of iodide, Uranine and Cr-EDTA in rock materials with fissure coating material is of the same magnitude or higher than in granites and gneisses. The results also show that it is not possible to assign one value to the diffusivity of a rock from a given area. The variations in properties are too large. The estimated effective diffusivity of iodide in rocks without fissure coating material was found to be in the range 1.10-14 m2/s to 70.10-14 m2/s.

To simulate the stress that exists in the bedrock at large depths, diffusion experiments with iodide and electrical resistivity measurements in rock materials under mechanical stress have been performed. It was found that the diffusivity in rock samples at 300–350 bars stress was reduced to 20–70% of the value in samples under atmospheric pressure.

Type
Research Article
Copyright
Copyright © Materials Research Society 1985

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References

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