Hostname: page-component-848d4c4894-ttngx Total loading time: 0 Render date: 2024-06-04T22:53:13.628Z Has data issue: false hasContentIssue false

Hydrothermal Crystallization of Ammonium-Saponite at 200 °C and Autogenous Water Pressure

Published online by Cambridge University Press:  28 February 2024

Roland J. M. J. Vogels
Affiliation:
Department of Inorganic Chemistry, University of Utrecht, P.O. Box 80.083, 3508 TB Utrecht, The Netherlands
Johan Breukelaar
Affiliation:
SRTCA (Shell Research B.V.), P.O. Box 38000, 1030 BN Amsterdam, The Netherlands
J. Theo Kloprogge*
Affiliation:
TNO-Institute of Applied Physics-TU Delft, Department of Inorganic Materials Chemistry, P.O. Box 595, 5600 AN Eindhoven, The Netherlands
J. Ben H. Jansen
Affiliation:
Bowagemi, Prinses Beatrixlaan 20, 3972 AN Driebergen, The Netherlands
John W. Geus
Affiliation:
Department of Inorganic Chemistry, University of Utrecht, P.O. Box 80.083, 3508 TB Utrecht, The Netherlands
*
Current address: Hoevenbos 299, 2716 Zoetermeer, The Netherlands.

Abstract

The effects of reaction time (2 to 72 h) and NH4+/A13+ molar ratio (1.6, 2.4 and 3.2) on the hydrothermal synthesis of ammonium-saponites are investigated. The gels are obtained by mixing powders, resulting in a stoichiometric composition, Mg3Si34Al0.6O10(OH)2, with aqueous ammonium solutions, with and without F, to result in initial NH4+/Al3+ molar ratios of 1.6, 2.4 and 3.2. The solid bulk products are characterized by X-raydiffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) analysis. The cation exchange capacity (CEC) is determined with an ammonia selective electrode and the pH of the water from the first washing is measured. Ammonium-saponite is formed rapidly within 16 h. A higher NH4+/A13+ molar ratio and the presence of F facilitate the crystallization of saponite. Small metastable amounts of bayerite, Al(OH)3, are present at low NH4+/A13+ molar ratios; after short reaction times, they disappear. During the first 4 h, the pH decreases rapidly, then drops slowly to a constant level of approximately 4.6 after 60 h. With increasing reaction time, saponite crystallites grow in the ab directions of the individual sheets with almost no stacking to thicker flakes. The NH4+ CEC of the solid products increases strongly within the first 24 h. A maximum of 53.3 meq/100 g is observed. The saponite yield increases from approximately 25% after 2 h to almost 100% after 72 h.

Type
Research Article
Copyright
Copyright © 1997, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

This paper is a joint contribution from the Debye Institute, Utrecht, and Shell Research B.V., Amsterdam, The Netherlands.

References

Hem, J.D. and Roberson, C.E.. 1967. Form and stability of aluminum hydroxide complexes in dilute solutions. USGS Water-Supply Paper 1827-A. Washington: US GPO. p 155.Google Scholar
Kloprogge, J.T.. 1992. Pillared clays: Preparation and characterization of clay minerals and aluminum-based pillaring agents. Geologica Ultraiectina 91 [Ph.D. thesis] Utrecht, The Netherlands: Univ of Utrecht. 349 p.Google Scholar
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 Miner 41: 103110.CrossRefGoogle Scholar
Kloprogge, J.T., Breukelaar, J., Wilson, A.E., Geus, J.W. and Jansen, J.B.H.. 1993. Solid-state nuclear magnetic resonance spectroscopy on synthetic ammonium/aluminum saponites. Clays Clay Miner 42: 416420.CrossRefGoogle Scholar
Kloprogge, J.T., van der Eerden, A.M.J., Jansen, J.B.H. and Geus, J.W.. 1990. Hydrothermal synthesis of Na-beidellite. Geol Mijnbouw 69: 351357.Google Scholar
Kloprogge, J.T., Jansen, J.B.H. and Geus, J.W.. 1990. Characterization of synthetic Na-beidellite. Clays Clay Miner 38: 409414.CrossRefGoogle Scholar
Loewenstein, W.. 1954. The distribution of aluminum in the tetrahedra of silicates and aluminates. Am Mineral 39: 9296.Google Scholar
Plee, D., Gatineau, L. and Fripiat, J.J.. 1987. Pillaring processes of smectites with and without tetrahedral substitution. Clays Clay Miner 35: 8188.CrossRefGoogle Scholar
Schutz, A., Stone, W.E.E., Poncelet, G. and Fripiat, J.J.. 1987. Preparation and characterization of bidimensional zeolitic structures obtained from synthetic beidellite and hydroxy-aluminum solutions. Clays Clay Miner 35: 251261.CrossRefGoogle Scholar
Shabtai, J., Rosell, M. and Tokarz, M.. 1984. Cross-linked smectites: III. Synthesis and properties of hydroxy-aluminum hectorites and fluorhectorites. Clays Clay Miner 32: 99107.CrossRefGoogle Scholar
Sterte, J. and Shabtai, J.. 1987. Cross-linked smectites: V. Synthesis and properties of hydroxy-silicoaluminum montmorillonites and fluorhectorites. Clays Clay Miner 35: 429439.CrossRefGoogle Scholar
Suquet, H., Iiyama, J.T., Kodama, H. and Pézerat, H.. 1977. Synthesis and swelling properties of saponites with increasing layer charge. Clays Clay Miner 25: 231242.CrossRefGoogle Scholar