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Use of hydrofluoric acid dissolution for the concentration of dickite and nacrite from kaolin deposits: an FTIR study

Published online by Cambridge University Press:  09 July 2018

A. R. Fraser ,
M. J . Wilson ,
M. J . Roe  and
Z. Y. Shen
A. R. Fraser*
Affiliation:
Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, UK
M. J . Wilson
Affiliation:
Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, UK
M. J . Roe
Affiliation:
Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, UK
Z. Y. Shen
Affiliation:
Department of Earth Sciences, Zhejiang University, Hangzhou, China
*
*E-mail: a.fraser@macaulay.ac.uk
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Abstract

A series of kaolin-rich mineral samples was treated with hydrofluoric acid (HF) and the residual material characterized using infrared (IR) spectroscopy, supplemented by scanning electron microscope (SEM) observations. By examining the hydroxyl-stretching region of the IR spectra before and after treatment with hydrofluoric acid, it was possible to identify the three kaolin polytypes – kaolinite, dickite and nacrite – with greater certainty. The SEM observations suggested that the rate of dissolution of the kaolin phase was largely dependent on particle size. In general, dickite and nacrite tend to occur in the coarser clay fractions, and for this reason the finer-grained kaolinite is preferentially dissolved by the HF treatment. However, in the Keokuk kaolinite, which occurs in exceptionally large particles, it was still possible to concentrate a dickitic fraction by HF treatment, suggesting that in some cases kaolinite may be more susceptible to HF dissolution for reasons other than particle size. The IR spectra of disordered kaolinite could be interpreted as arising from a mixture of kaolinite and dickite components. However, both components dissolve at the same rate in HF, supporting the idea that disordered kaolinite consists of an intimate association of randomly stacked dickite-like and kaolinite-like components.

Keywords

Hydrofluoric acidinfrared spectroscopykaolinitedickitenacrite
Type
Research Article
Information
Clay Minerals , Volume 37 , Issue 3 , September 2002 , pp. 559 - 570
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2002

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References

Ehrenberg, S.N., Aagard, P., Wilson, M.J., Fraser, A.R. & Duthie, D.M.L. (1993) Depth-dependent transformation of kaolinite to dickite in sandstones of the Norwegian continental shelf. Clay Minerals, 28, 325–352.Google Scholar
Farmer, V.C. & Russell, J.D. (1964) The infrared spectra of layer silicates. Spectroc himica Acta. 20, 1149–1173.Google Scholar
Hayes, J.B. (1963) Kaolinite from Warsaw geodes, Keokuk region, Iowa. Iowa Academy of Science, 70, 261–272.Google Scholar
Keller, W.D. (1976) Scan electron micrographs of kaolins collected from diverse environments of origin. – 1. Clays and Clay Minerals, 24, 107–113.Google Scholar
Keller, W.D., Pickett, E.E. & Reesman, A.L. (1966) Elevated dehydroxylation temperature of the Keokuk geode kaolinite – a possible reference mineral. Proceedings of the International Clay Conference, 1966, Jerusalem, 75–85.Google Scholar
Norrish, K. (1968) Some phosphate minerals of soils. Pp. 713–723 in. Transactions of the 9th International Congress of Soil Science, Adelaide, 2.Google Scholar
Robertson, R.H.S., Brindley, G.W. & Mackenzie, R.C. (1954) Mineralogy of kaolin clays from Pugu, Tanganyika. American Mineralogist, 39, 118.Google Scholar
Rouxhet, P.G., Samudacheata, N., Jacobs, H. & Anton, O. (1977) Attribution of the OH stretching bands of kaolinite. Clay Minerals, 12, 171–179.Google Scholar
Russell, J.D. & Fraser, A.R. (1994) Infrared methods. Pp 11–67 in: Clay Mineralogy: Spectroscopic and Chemical Determinative Methods (Wilson, M.J., editor). Chapman & Hall, London.Google Scholar
Russell, J.D. & Kirkpatrick, W.M. (1992) Nacrite from the Souther n Upland fault nea r Abington, Strathclyde, Scotland. Clay Minerals, 27, 253–255.Google Scholar
Shen, Z.Y. (1993) The mineralogy and origin of kaolinrich deposits of eastern China. M.Sc. thesis, University of Aberdeen, Scotland.Google Scholar
Shen, Z.Y., Wilson, M.J., Fraser, A.R. & Pearson, M.J. (1994) Nacritic clay associated with the Jiangshan- Shaoxing deep fault in Zhejiang Province, China. Clays and Clay Minerals, 42, 576–581.Google Scholar
Smithson, F. & Brown, G. (1957) Dickite from sandstones in Northern England and North Wales. Mineralogical Magazine, 31, 381–391.Google Scholar
Wada, K. (1965) Intercalation of water in kaolin minerals. American Mineralogist, 50, 924–941.Google Scholar