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Clays and Clay Minerals

, Volume 11, Issue 1, pp 47–64 | Cite as

Negative Charge of Dioctahedral Micas as Related to Weathering

  • M. G. Cook
  • C. I. Rich
Symposium on Clay Mineral Transformation

Abstract

Negative charge and related characteristics of dioctahedral micas have been investigated by conducting artificial weathering studies on a muscovite from Ontario, Canada, and saprolitic micas from Virginia. Emphasis is given to the relationship between loss of potassium, increase in net negative charge, or cation exchange capacity, and expansion characteristics.

Boiling solutions of acetic acid, sodium chloride and magnesium chloride removed potassium and sodium from a saprolitic mica but produced a negligible increase in cation exchange capacity. Expansion of the mica structure occurred following treatment with salt solutions but not with acid solutions. Boiling solutions of sodium citrate removed potassium effectively, produced marked expansion, and caused a large increase in cation exchange capacity. The small increase in cation exchange capacity resulting from acid and salt treatments is attributed to the hydrolysis of exchangeable aluminum to form hydroxy-aluminum polymeric groups, which can occupy exchange sites but remain non-exchangeable. The results of the sodium citrate tratement are attributed to the complexing of aluminum by citrate, thus releasing the hydroxy-aluminum polymeric groups from exchange positions and permitting an increase in cation exchange capacity.

Molten lithium nitrate treatment of specimen muscovite produced a greater increase in cation exchange capacity than in the case of muscovite separated from soil-forming mica phyllite. The observed difference in charge characteristics, concomitant with the greater expansion of the muscovite, suggest that soil micas and specimen-type micas differ in their alteration tendencies.

When interlayer hydroxy groups are eliminated and account is taken of residual sodium, potassium, and water, dioctahedral micas apparently lose no negative charge on expansion to vermiculite-like minerals.

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References

  1. Barshad, I. (1959) Vermieulite and its relation to biotite as revealed by base-exchange reactions, X-ray analyses, differential thermal curves, and water content: Amer. Min., v.33, pp.655–678.Google Scholar
  2. Barshad, I. (1954) Cation exchange in micaceous minerals. II. Replaceability of ammonium and potassium from vermiculite, biotite and montmorillonite: Soil Sci., v.78, pp.57–75.CrossRefGoogle Scholar
  3. Barshad, I. (1960) X-ray analysis of soil colloids by a modified salted paste method: in Clays and Clay Minerals, 7th Conf., Pergamon Press, pp. 350–364.Google Scholar
  4. Corey, R. B. and Jackson, M. L. (1953) Silicate analysis by a rapid semimicrochemical system: Anal. Chem., v.25, pp.624–628.CrossRefGoogle Scholar
  5. Hashimoto, I. and Jackson, M. L. (1960) Rapid dissolution of allophane and kaolinite-halloysite after dehydration: in Clays and Clay Minerals, 7th Conf., Pergamon Press, pp.102–113.Google Scholar
  6. Jackson, M. L. (1956) Soil Chemical Analysis—Advanced Course. Published by the author. University of Wisconsin, Madison, 991 pp.Google Scholar
  7. Mackenzie, R. C. and Milne, A. A. (1953) The effect of grinding on micas: I. Muscovite: Min. Mag., v.30, pp.178–185.Google Scholar
  8. Mehra, O. P. and Jackson, M. L. (1960) Iron oxide removal from soils and clays by a dithionite-eitrate system buffered with sodium carbonate: in Clays and Clay Minerals, 7th Conf., Pergamon Press, pp.317–327.Google Scholar
  9. Rich, C.I. (1957) Determination of (060) reflections of clay minerals by means of counter type X-ray diffraction instruments: Amer. Min., v.42, pp.569–570.Google Scholar
  10. Rich, C. I. (1960) Aluminum in interlayers of vermiculite: Soil Sci. Soc. Amer. Proc, v.24, pp.26–32.CrossRefGoogle Scholar
  11. Rich, C. I. (1961) Calcium determination for cation exchange capacity measurements: Soil Sci., v.92, pp.226–231.CrossRefGoogle Scholar
  12. Rich, C. I. and Cook, M. G. (1962) Formation of dioctahedral vermiculite in Virginia soils: in Clays and Clay Minerals, 10th Conf., Pergamon Press. In press.Google Scholar
  13. Schaller, W. T. (1950) An interpretation of the composition of high silica sericites: Min. Mag., v.29, pp.406–415.Google Scholar
  14. Stose, G. W. (1928) Supervisor of preparation, Geologic Map of Virginia. Virginia Geological Survey.Google Scholar
  15. Tamura, T. (1958) Identification of clay minerals from acid soils. Jour. Soil Sci., v.9, pp.141–147.CrossRefGoogle Scholar
  16. White, J. L. (1956) Reactions of molten salts with layer-lattice silicates: in Clays and Clay Minerals, Natl. Acad. Sci.—Natl. Res. Council, pub. 456, pp. 133–146.Google Scholar
  17. White, J. L. (1958) Layer charge and interlamellar expansion in a muscovite: in Clays and Clay Minerals, Natl. Acad. Sci.—Natl. Res. Council, pub. 566, pp.289–294.Google Scholar

Copyright information

© The Clay Minerals Society 1962

Authors and Affiliations

  • M. G. Cook
    • 1
  • C. I. Rich
    • 1
  1. 1.Agronomy DepartmentVirginia Polytechnic InstituteBlacksburgUSA

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