Clays and Clay Minerals

, Volume 8, Issue 1, pp 183–192 | Cite as

Hydration Properties of Potassium Deficient Clay Micas

  • Edward C. Jonas
  • George L. Thomas


A clay mineral that in its natural state expands to 15Å with water and to 17 Å with ethylene glycol was treated with various concentrations of KCl. At the highest KC1 concentration all the material was rendered nonexpanding. There was a threshold KC1 concentration at which potassium ions were absorbed in sufficient quantities to prevent expansion of the clay in water. At concentrations less than the threshold the material is characterized by a random interlayer mixture of expanding and nonexpanding layers. The sequence produced with increasing KC1 concentration is: expanding clay → interlayer mixture → nonexpanding clay.

Solvation with ethylene glycol is more effective than solvation with water for much higher potassium ion population densities in the interlayer space. At potassium ion population densities intermediate between those at the concentration thresholds for water solvation and for ethylene glycol solvation, there are layers that will expand with glycol and not with water.

Low potassium ion population densities correspond to low surface charge densities of potassium saturated clays, and the clays expand like montmorillonite. The high potassium ion population densities correspond to high surface charge densities of potassium-saturated clays and illite and the clays do not expand. With intermediate potassium ion population densities corresponding to intermediate surface charge densities for potassium-saturated clays, the clays expand with ethylene glycol but not with water.


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  1. Hathaway, J. C. (1956) Procedure for clay mineral analyses used in the sedimentary petrology laboratory of the U.S. Geological Survey: Clay Minerals Bulletin, v. 3, pp. 8–13.CrossRefGoogle Scholar
  2. Johns, W. D. and Tettenhorst, R. T. (1959) Differences in the montmorillonite solvating ability of polar liquids: Amer. Min., v. 44, pp. 894–896.Google Scholar
  3. Jonas, E. C., and Roberson, H. E. (1960) Particle size as a factor influencing expansion of the three-layer clay minerals: Amer. Min., v. 45, pp. 828–838.Google Scholar
  4. Walker, G. F. (1950) Trioctahedral minerals in the soil clays of north-east Scotland: Min. Mag., v. 29, pp. 72–84.Google Scholar
  5. Walker, G. F. (1958) Reactions of expanding-lattice clay minerals with glycerol and ethylene glycol: Clay Minerals Bulletin, v. 3, pp. 302–313.CrossRefGoogle Scholar
  6. Weaver, C. E. (1958) The effects and geologic significance of potassium “fixation” by expandable clay minerals derived from muscovite, biotite, chlorite, and volcanic material: Amer. Min., v. 43, pp. 839–861.Google Scholar

Copyright information

© The Clay Minerals Society 1959

Authors and Affiliations

  • Edward C. Jonas
    • 1
  • George L. Thomas
    • 1
  1. 1.The University of TexasAustinUSA

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