Abstract
Saponites were hydrothermally grown in the presence of amounts of NH4+, Na+, K+, Rb+, Ca2+, Ba2+, and Ce4+ equivalent with the CEC of the saponite (155 meq/100 g), with or without F−, at a temperature of 200°C for 72 hr. XRD and CEC data revealed the formation of a two-water-layer saponite with mainly Mg2+ as interlayer cation. Dehydration occurred between 25° and 450°C and dehydroxylation occurred in two steps between 450° and 790°C and between 790° and 890°C. The relatively small length of the b-axis between 9.151 and 9.180 Å is explained by considerable octahedral Al substitution (between 0.28 and 0.70 per three sites) and minor tetrahedral Al substitution (between 0.28 and 0.58 per four sites). Under the synthesis conditions applied in this study, less than 13% of the interlayer sites are occupied by Na+, K+, and Rb+; between 13.3% and 21% by Ca2+ and Ba2+; while NH4+ gives the highest value at 34%. The remaining sites are mainly filled by Mg2+. Ce4+ is not found in the saponite structure due to the formation of cerianite, CeO2. The presence of F− had little influence on the saponite composition. The formation of Mg-saponites is explained by a model in which an increased bayerite formation resulting in a higher octahedral Al3+ substitution and more Mg2+ in solution. Mg2+ is preferentially incorporated compared with the other interlayer cations due to its smallest ionic radius in combination with its 2 + charge.
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References
Giese, R. F. (1984) Electrostatic energy models of micas: in Micas, Reviews in Mineralogy, Vol. 13, S. W. Bailey, ed., Mineralogical Society of America, Washington, D.C., 105–141.
Iwasaki, T., Onodera, Y., and Torii, U. (1989) Rheological properties of organophyllic synthetic nectorites and saponites: Clays & Clay Minerals 37, 240–257.
Kloprogge, J. T. (1992) Pillared Clays, Preparation and Characterization of Clay Minerals and Aluminum-based Pillaring Agents: Geologica Ultraiectina 91, Ph.D. thesis, University of Utrecht, The Netherlands, 349 pp.
Kloprogge, J. T., Breukelaar, J., Jansen, J. B. H., and Geus, J. W. (1993) Development of ammonium-saponites from gels with variable ammonium concentration and water content at low temperatures: Clays & Clay Minerals 41, 103–110.
Koizumi, M. and Roy, R. (1959) Synthetic montmorillonoids with variable exchange capacity: Amer. Mineral. 44, 788–803.
Munoz, J. L. (1984) F-OH and Cl-OH exchange in micas with applications to hydrothermal ore deposits: in Micas, Reviews in Mineralogy, Vol. 13, S. W. Bailey, ed., Mineralogical Society of America, Washington, D.C., 469–491.
Suquet, H., de La Calle, C., and Pezerat, H. (1975) Swelling and structural organization of saponite: Clays & Clay Minerals 23, 1–9.
Suquet, H., Iiyama, J. T., Kodama, H., and Pezerat, H. (1977) Synthesis and swelling properties of saponites with increasing layer charge: Clays & Clay Minerals 25, 231–242.
Suquet, H., Malard, C., Copin, E., and Pezerat, H. (1981a) Variation du parametre b et de la distance basale d001 dans une serie de saponites a charge croissante: I. Etats hydrates: Clay Miner. 16, 53–67.
Suquet, H., Malard, C., Copin, E., and Pezerat, H. (1981b) Variation du paramètre b et de la distance basale d001 dans une serie de saponites a charge croissante: H. Etats ‘zero couche’: Clay Miner. 16, 181–193.
Suquet, H., Prost, R., and Pezerat, H. (1982) Etude par spectroscopic infrarouge et diffraction X des interactions eau-cation-feuillet dans les phases a 14.6, 12.2 and 10.1 Å d’une saponite-Li de synthese: Clay Miner. 17, 231–241.
Suquet, H. and Pezerat, H. (1987) Parameters influencing layer stacking types in saponite and vermiculite: A review: Clays & Clay Minerals 35, 353–362.
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This paper is a joint contribution of the Debye Institute, University of Utrecht, The Netherlands and Shell Research B.V.
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Kloprogge, J.T., Breukelaar, J., Geus, J.W. et al. Characterization of Mg-Saponites Synthesized from Gels Containing Amounts of Na+, K+, Rb+, Ca2+, Ba2+, or Ce4+ Equivalent to The CEC of the Saponite. Clays Clay Miner. 42, 18–22 (1994). https://doi.org/10.1346/CCMN.1994.0420103
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DOI: https://doi.org/10.1346/CCMN.1994.0420103