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Geometry Effects for Specific Electrical Conductance in Clays and Soils

Published online by Cambridge University Press:  01 July 2024

A. Cremers
Affiliation:
Institute of Agronomy, University of Louvain, Heverle-Louvain, Belgium
J. van Loon
Affiliation:
Institute of Agronomy, University of Louvain, Heverle-Louvain, Belgium
H. Laudelout
Affiliation:
Institute of Agronomy, University of Louvain, Heverle-Louvain, Belgium
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Abstract

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A systematic study of the influence of salinity and clay content on the electrical conductivity of sodium-illite clay gels shows that the geometry or “formation resistivity factors” of such systems can adequately be described by the model of oblate ellipsoids, used to simulate the shape of the clay particles. This conclusion is in agreement with the results previously obtained on kaolinite and montmorillonite clays. An axial ratio of 16 was found for the illite clay particles.

On the basis of Burger’s and Maxwell’s equations for electric flow through porous media, formulae are derived for calculating the electrical conductivity of mixed systems, i.e. “clay 1 + clay 2 + electrolyte solution” and “clay + spherical particles + electrolyte solution”. The electrical conductivity of these systems is expressed in terms of the shape parameters, surface conductances, specific surfaces and volume concentrations of the constituents. The type of equation can eventually lead to an explanation (in terms of a non-uniform particle shape distribution) of the anomalous geometry effects in some clays.

Experimental results conform fairly well to the equations. Glass powder at volume fraction between 0.18 and 0.60 added to a 17.4% montmorillonite gel acts as an inert diluent on the specific electrical conductivity of the mixture. For a mixture of 1 part montmorillonite to 9 parts kaolinite, the measured specific electrical conductivity agrees within about 10% with the predicted over the range studied (volume fraction of montmorillonite: 0.035 to 0.039; mixture porosity: 0.61 to 0.660; salt concentration range: 0.5 n to 2 n NaCl).

Type
Research Article
Copyright
Copyright © Clay Minerals Society 1966

References

Anderson, D. M. and Low, P. F. (1958) The density of water adsorbed by lithium, sodium and potassium bentonite, Proc. Soil Sci. Soc. Amer. 22, 99103.CrossRefGoogle Scholar
Archie, G. E. (1942) The electrical conductivity log as an aid in determining some reservoir characteristics, Trans. A.I.M.E. 146, 5562.Google Scholar
Bloksma, A. H. (1957) The diffusion of sodium and iodide ions and urea in clay pastes, Jour. Coll. Sci. 12, 40.52.CrossRefGoogle Scholar
Böttcher, C. J. F. (1945) The dielectric constant of crystalline powders, Ree. Trav. Chim. Pays Bas. 64, 4751.CrossRefGoogle Scholar
Bruggeman, D. A. G. (1935) The calculation of various physical constants of heterogeneous substances. I. The dielectric constants and conductivities of mixtures composed of isotropic substances, Ann. Physik. 24, 636–64.Google Scholar
Burger, H. C. (1919) Das Leitvermögen verdünnter mischkristallfreien Legierungen, Phys. Zeits. 20, 73–5.Google Scholar
Clark, N. O. (1948) Electrical conductivity of foam, Trans. Faraday Soc. 44, 1315.CrossRefGoogle Scholar
Cremers, A. and Laudelout, E. (1965a) Conductivity électrique des gels argileux et anisométrie de leurs éléments, Jour. Chim. Phys. 62, 1155–62.Google Scholar
Cremers, A. and Laudelout, H. (1956) On the “Isoconductivity value” of clay gels, Soil Sci. 100, 298–9.Google Scholar
Dakshinamurti, S. (1960) Studies on the conductivity of clay systems, Soil Sci. 90, 302–5.10.1097/00010694-196011000-00008CrossRefGoogle Scholar
Dutt, G. R. and Low, P. F. (1961) Relationship between the activation energy for deuterium oxide diffusion and exchangeable ion conductance in clay systems, Soil Sci. 93, 195203.CrossRefGoogle Scholar
Fricke, H. (1924) A mathematical treatment of the electrical conductivity and capacity of disperse systems, Phys. Rev. 24, 575–87.CrossRefGoogle Scholar
Glasstone, S., Laidler, K. J. and Eyring, H. (1941) The Theory of Rate Processes, McGraw-Hill, New York.Google Scholar
Lai, T. M. and Mortland, M. M. (1961) Diffusion of ions in bentonite and vermiculite, Proc. Soil Sci. Soc. Amer. 25, 353–7.10.2136/sssaj1961.03615995002500050014xCrossRefGoogle Scholar
Lai, T. M. and Mortland, M. M. (1962) Self-diffusion of exchangeable cations in bentonite, Clays and Clay Minerals, Proc. 9th Conf., Pergamon Press, New York, 229–47.Google Scholar
Leonard, R. A. and Low, P. F. (1964) Effect of salt on water movement in soils, Presented at meeting of Amer. Soc. Agronomy in Kansas City.Google Scholar
Low, P. F. (1962) Influence of adsorbed water on exchangeable ion movement, Clays and Clay Minerals, Proc. 9th Conf., Pergamon Press, New York, 219–28.Google Scholar
Low, P. F. (1958) The apparent mobilities of exchangeable alkali metal cations in bentonite water systems, Proc. Soil Sci. Soc. Amer. 22, 395–8.10.2136/sssaj1958.03615995002200050008xCrossRefGoogle Scholar
Martin, H. and Laudelout, H. (1963) Thermodynamique de l’échangé des cations alcalins dans les argiles, Jour. Chim. Phys. 60, 1086–99.Google Scholar
Maxwell, C. (1887) A Treatise on Electricity and Magnetism, 2nd ed. Vol. I, 435, Clarendon Press, Oxford.Google Scholar
Meredith, R. E. (1959) Studies on the conductivities of dispersions, Lawrence Radiation Laboratory Report, U.C.R.L.—8667.Google Scholar
Meredith, R. E. and Tobias, C. W. (1962) Conduction in heterogeneous systems, Adv. Electr. and Electrochem. Engr. 2, 1547.Google Scholar
Patnode, H. W. and Wyllie, M. R. J. (1950) The presence of conductive solids in reservoir rocks as a factor in electric log interpretation, Trans. A.I.M.E. 189, 4752.Google Scholar
Penman, H. L. (1940a) Gas and vapor movements in the soil. I. The diffusion of vapours through porous solids, Jour. Agr. Sci. 30, 437–62.Google Scholar
Penman, H. L. (1906) Gas and vapor movements in the soil. II. The diffusion of carbondioxide through porous solids, Jour. Agr. Sci. 30, 570–81.Google Scholar
Street, N. (1956a) Effect of surface conductance on drilling mud resistivity, Bull. Amer. Assoc. Petrol Geol. 40, 19962000.Google Scholar
Street, N. (1966) The surface conductance of kaolinite, Australian Jour. Chem. 9, 333–46.Google Scholar
Street, N. (1963) On “the Isoconductivity value” of clays, Soil Sci. 95, 367.Google Scholar
Wyllie, M. R. J. and Southwick, P. P. (1954) An experimental investigation on the S.P. and resistivity phenomena in dirty sands, Trans. A.I.M.E. 201, 4356.Google Scholar