Experimental Transformation of Kaolinite to Halloysite
A well-characterized kaolinite has been hydrated in order to test the hypothesis that platey kaolinite will roll upon hydration. Kaolinite hydrates are prepared by repeated intercalation of kaolinite with potassium acetate and subsequent washing with water. On hydration, kaolinite plates roll along the major crystallographic directions to form tubes identical to proper tubular halloysite. Most tubes are elongated along the b crystallographic axis, while some are elongated along the a axis. Overall, the tubes exhibit a range of crystallinity. Well-ordered examples show a 2-layer structure, while poorly ordered tubes show little or no 3-dimensional order. Cross-sectional views of the formed tubes show both smoothly curved layers and planar faces. These characteristics of the experimentally formed tubes are shared by natural halloysites. Therefore, it is proposed that planar kaolinite can transform to tubular halloysite.
Key WordsHalloysite Hydration Intercalation Kaolinite Rolling Tetrahedral Rotation
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- Bailey SW. 1989. Halloysite—A critical assessment. In: Farmer VC, Tardy Y, editors. Proceedings of the International Clay Conference; Strasbourg, France. Sci Geol Mem 86:89–98.Google Scholar
- Bates TF, Hildebrand FA, Swineford A. 1950. Morphology and structure of endellite and halloysite. Am Mineral 6: 237–248.Google Scholar
- Costanzo PM, Giese RF, Jr. 1985. Dehydration of synthetic hydrated kaolinites: a model for the dehydration of halloysite (10 Â). Clays Clay Miner 33:425-423.Google Scholar
- Deed CT, van Olphen H, Bradley WH. 1966. Intercalation and interlayer hydration of minerals of the kaolinite group. In: Heller L, Weiss A, editors. Proceedings of the International Clay Conference; 1966; Jerusalem, Israel; Vol. 1. Jerusalem: Programs of Science in Translation, p 183–199.Google Scholar
- Radoslovich EW 1963. The cell dimensions and symmetry of layer-lattice silicate: VI. Serpentine and kaolin morphology. Am Mineral 48:368–378.Google Scholar
- Wada K. 1961. Lattice expansion of kaolin minerals by treatment with potassium acetate. Am Mineral 46:78–91.Google Scholar
- Wada K. 1965. Intercalation of water in kaolin minerals. Am Mineral 50:924–941.Google Scholar