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Compositional Variation of a Vermiculite as Related to Particle Size

Published online by Cambridge University Press:  01 July 2024

Raymond L. Kerns Jr.  and
Charles J. Mankin
Raymond L. Kerns Jr.
Affiliation:
Oklahoma Geological Survey, University of Oklahoma, Norman, Oklahoma
Charles J. Mankin
Affiliation:
School of Geology, University of Oklahoma, Norman, Oklahoma
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Abstract

A vermiculite regolith sample from Llano, County, Texas, was divided into 16–32, 8–16, 4–8, 2–4, 1–2, ½–1, ¼–½, 1/10-1/4, and 5/100–1/10 micron equivalent spherical diameter size-classes. A well-crystallized vermiculite found in association with the regolith was ground to −400 mesh.

The samples were analyzed by X-ray diffractometry and differential thermal analysis, and cation exchange capacity measurements were made for selected size fractions. Chemical analyses by X-ray fluorescence revealed a systematic increase in silicon with decreasing particle size. An increase in the iron content and a decrease in magnesium were also directly correlated to a decrease in the crystallite size. Aluminum content was constant throughout the range of particle sizes.

X-ray analyses showed that the coarser particles were trioctahedral, whereas the smaller crystallites were dioctahedral. These data were supported by recast formulae based on the chemical analyses. The recast formulae were substantiated by DTA and cation exchange capacity data as being reasonable approximations of actual formulae.

These observations are interpreted as an expression of chemical alteration that clay minerals may undergo in an aqueous environment. The crystallographic, cation exchange capacity, DTA, and swelling properties are a function of the chemical composition of the crystallites. Chemical composition of the crystallites is shown to be directly correlated to particle size.

Type
Symposium on Vermiculite Studies
Information
Clays and Clay Minerals , Volume 15 , February 1967 , pp. 163 - 177
Copyright
Copyright © 1967, The Clay Minerals Society

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References

Barnes, U. E. and Clabaugh, S. E. (1961) Vermiculite deposits near Llano, Texas: Texas Univ., Guidebook 3, 45–53.Google Scholar
Clabaugh, S. E. and Barnes, V. E. (1959) Vermiculite in central Texas: Texas Univ., Rep. of Invest. 40, 32 pp.Google Scholar
Fyfe, W. S. (1951) Isomorphism and bond type: Amer. Min. 36, 538–42.Google Scholar
Jonas, E. C. (1960) Mineralogy of the micaceous clay minerals: Proc. Internat. Comm. Study Clays, Copenhagen, 1–16.Google Scholar
Jonas, E. C. (1963) Ion exchange at edge and interlayer in montmorillonites differing in size: Science 140, 75–6.CrossRefGoogle ScholarPubMed
Jonas, E. C. and Roberson, H. E. (1960) Particle size as a factor influencing expansion of the three-layer clay minerals: Amer. Min. 45, 828–38.Google Scholar
Marshall, C. E. (1949) The Colloid Chemistry of the Silicate Minerals: Academic Press, New York, 195 pp.Google Scholar
Paige, S. (1912) Description of the Llano and Burnet quadrangles: U.S. Geol. Surv. Geol. Atlas, Llano-Burnet Folio (No. 183), 16 pp.Google Scholar
Pauling, L. (1948) The Nature of the Chemical Bond: Cornell University Press, Ithaca, New York.Google Scholar
Roberson, H. E. and Jonas, E. C. (1965) Clay minerals intermediate between illite and montmorillonite: Amer. Min. 50, 766–70.Google Scholar
Walker, G·. F. (1961) Vermiculite minerals, Chap. VII in X-ray Identification and Crystal Structures of Clay Minerals: Mineralogical Society, London.Google Scholar
Weaver, C. E. (1958) The effects and geologic significance of potassium “fixation” by expanding clay minerals derived from muscovite, biotite, chlorite, and volcanic material: Amer. Min. 43, 839–61.Google Scholar