Synthesis of kaolinite from micas and K-depleted micas
Cho, Yunchul (The Pennsylvania State University. Department of Crop and Soil Sciences)
Komarneni, Sridhar (The Pennsylvania State University. Department of Crop and Soil Sciences)

Date:	2007
Abstract:	The weathering stages of K-depleted biotite, K-depleted phlogopite, and natural biotite were investigated using hydrothermal treatment with AlCl solution at 200°C for 12 to 72 h. Although there were some differences in the degree of weathering of the two K-depleted micas, both first transformed to hydroxy-Al interlayered vermiculite (HIV), which then altered to kaolinite. In case of the natural biotite, the biotite first transformed to a K-depleted mica-like phase, which then altered to kaolinite. The natural biotite had resisted weathering to kaolinite more than did the K-depleted biotite, as expected. The K-depleted phlogopite had less resistance in weathering to kaolinite than the K-depleted biotite. The transformation process changed the color of the micas. The K-depleted biotite changed from greenish-black through yellow to pale gray whereas the natural biotite changed from greenish-black through beige to yellow. However, in the case of K-depleted phlogopite, there was no significant color change during the transformation process. The presence of the interlayer K ions and the structural Fe ions in mica appear to have contributed to the differences in the degree of weathering to kaolinite among the micas investigated.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Hydrothermal Treatment ; Hydroxy Al-interlayered Vermiculite (HIV) ; Kaolinite ; K-depleted Biotite ; K-depleted Phlogopite ; Transformation ; Weathering
Published in:	Clays and Clay Minerals, Vol. 55, Núm. 6 (2007) , p. 565-571, ISSN 1552-8367

DOI: 10.1346/CCMN.2007.0550603

7 p, 694.6 KB  UAB restricted access

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