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Structural Organization in Amorphous Silico-Aluminas

Published online by Cambridge University Press:  01 July 2024

P. Cloos ,
A. J. Léonard ,
J. P. Moreau ,
A. Herbillon  and
J. J. Fripiat
P. Cloos*
Affiliation:
Laboratoire de Physico-Chimie Minérale, Institut des Sciences de la Terre, 42, de Croylaan, Heverlee-Louvain, Belgium
A. J. Léonard*
Affiliation:
Laboratoire de Physico-Chimie Minérale, Institut des Sciences de la Terre, 42, de Croylaan, Heverlee-Louvain, Belgium
J. P. Moreau*
Affiliation:
Laboratoire de Physico-Chimie Minérale, Institut des Sciences de la Terre, 42, de Croylaan, Heverlee-Louvain, Belgium
A. Herbillon*
Affiliation:
Laboratoire de Physico-Chimie Minérale, Institut des Sciences de la Terre, 42, de Croylaan, Heverlee-Louvain, Belgium
J. J. Fripiat*
Affiliation:
Laboratoire de Physico-Chimie Minérale, Institut des Sciences de la Terre, 42, de Croylaan, Heverlee-Louvain, Belgium
*
*The University of Louvain.
*The University of Louvain.
†Research Associated to “Ciments Lafarge”, France.
‡The University of Louvain and M.R.A.C. (Tervuren).
‡The University of Louvain and M.R.A.C. (Tervuren).
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Abstract

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A structure model for amorphous hydrated or dehydrated silico-aluminas with composition varying between 0 < Al: Al + Si < 1 is presented. A central core made from a tetrahedral network in which silicon is partially substituted by aluminium carries a net negative electrical charge. This charge is balanced by more or less polymerized hydroxyaluminium cations forming a coating around the core.

As Al: Al + Si increases, the number of substitutions in the core increases as well as the complexity of the hydroxyaluminium cations in the coating.

For Al: Al + Si ≳ 0·8, a demixing is observed, leading to the formation of a crystalline pseudo-boehmite and bayerite.

Upon heating, the coating as well as the demixed phases are transformed into a spinel structure containing tetrahedral aluminium, while the core structure remains unaffected.

This model could explain the solubility features, the phosphate reaction and the catalytic properties of amorphous silico-aluminas.

Résumé

Résumé

In modèle présente de structure pour des silico-alumines amorphes hydratés ou deshydratés, dont la composition varie entre O < Al: Al + Si < 1. Un noyau central construit à partir d’un réseau tetraédrique dans lequel la silice est substituée en partie par l’aluminium, porte une charge électrique négative. Cette charge est équilibrée par des cations hydroxy-aluminium plus ou moins polymérisés formant une couche autour du noyau. Tandis que Al:Al + Si augmentent, le nombre de substitutions dans le noyau s’accroit ainsi que la complexité des cations hydroxy-aluminium dans le revêtement. Pour Al:Al + Si ≳ 0,8, on observe un démixage qui conduit à la formation d’un pseudo-boehmite cristallin et bayerite. Par l’action du chauffage, le revêtement ainsi que les phases de démixage sont transformés en une structure spinelle contenant de l’aluminium tétrahydrique, tandis que la structure du noyau rest inchangée. Ce modèle pourrait expliquer les caractéristiques de solubilité, la réaction du phosphate et les propriétés catalytiques des silico-alumines amorphes.

Kurzreferat

Kurzreferat

Ein Strukturmodell für amorphe hydrierte bzw. dehydrierte Silica-Tonerden mit einer Zusammensetzung zwischen 0< Al: Al + Si < 1 wird erörtert. Ein zentraler Kern, der aus einem tetrahedralen Netz, in dem Silizium teilweise durch Aluminium substituiert ist, besteht, trägt eine Nettoladung negativer Elektrizität. Diese Ladung wird durch mehr oder weniger polymer-isierte Hydroxy-Aluminium-Kationen ausgeglichen, die eine Schale rings um den Kern bilden. Mit zunehmenden Al:Al + Si nimmt auch die Anzahl der Substituierungen in dem Kern zu, wie auch die Kompliziertheit der Hydroxy-Aluminium-Kationen in der Schale. Bei Al:Al + Si≥0,8 beobachtet man eine Entmischung, die zur Bildung von kristallischem Pseudoböhmit und Bayerit führt. Nach der Erwärmung werden die Schale und die entmischten Phasen in eine Spinellstruktur umgewandelt, die tetrahedrales Aluminium enthält, während die Kernstruktur unberührt bleibt. Dieses Modell könnte die Löslichkeitsmerkmale. die Phosphatreaktion und die katalytischen Eigenschaften amorphe-Silica-Tonerden erklären.

Резюме

Резюме

Предложена структурная модель для аморфной гидратированной или дегидратиро¬ванной смеси кремнезема и глинозема, состав которой изменяется в пределах: О<А1: А1 + Si < 1. Внутреннее ядро образовано тетраэдрической сеткой, в которой кремний частью замещен алюминием; сетка имеет отрицательный заряд. Этот заряд компенсируется более или менее полимеризованными гидроксиалюминиевыми катионами, образующими оболочку вокруг ядра.

С возрастанием отношения А1: А1 + Si число замещений в ядре увеличивается, а компле¬ксность гидроксиалюминиевых катионов в оболочках усиливается.

При отношении А1: А1 + Si ≳0,8 наблюдалось обособление глинозема с образованием кристаллических псевдобёмита и байерита. После нагревания как оболочки так и обособившие¬ся кристаллические фазы дали вещество со шпинелевой структурой, содержащее алюминий в тетраэдрической координации; при этом структура ядра не изменилась.

Предложенная модель может объяснить особенность растворения, фосфатную реакцию и каталитические свойства аморфных алюмокремниевых смесей.

Type
Research Article
Information
Clays and Clay Minerals , Volume 17 , Issue 5 , October 1969 , pp. 279 - 287
Copyright
Copyright © 1969, The Clay Minerals Society

References

Barthomeuf, D., Ballivet, D., Devaux, R. and Trambouze, Y. (1967) Caractérisation de la phase active dans un catalyseur silice-alumine: Bull. Soc. Chim. France 1495–1502.Google Scholar
Brosset, C., Biedermann, G. and Sillen, L. G. (1954) Studies on the hydrolysis of metal ions: Acta Chem. Scand. 8, 1917–1926.CrossRefGoogle Scholar
Cashen, G. H. (1963) Electric charges and thixotropy of clays: Nature 197, 349–350.CrossRefGoogle Scholar
Cashen, G. H. (1966) Electric charges of clays: J. Soil Sci. 17, 303–315.CrossRefGoogle Scholar
Cloos, P., Herbillon, A. and Echeverría, J. (1968) Allophane-like synthetic silico-aluminas. Phosphate adsorption and availability: Trans 9th Intern. Congr. Soil Sci. 11, 733–743.Google Scholar
Danforth, J. D. (1960) Structures and chemical characteristics of cracking catalysts by ion exchange: Actes 2e Congr. Intern. Catalyse, Paris 1, 1271–1286.Google Scholar
De Kimpe, C., Gastuche, M. C. and Brindley, G. W. (1961) Ionic coordination in alumino-silicic gels in relation to clay mineral formation: Am. Mineralogist 46, 1370–1381.Google Scholar
De Kimpe, C. Gastuche, M. C. and Brindley, G. W. (1964) Low temperature syntheses of kaolin minerals: Am. Mineralogist 49, 1–16.Google Scholar
De Kimpe, (1967) S. Hydrothermal aging of synthetic alumino-silicate gels: Clay Minerals 7, 203–214.CrossRefGoogle Scholar
de Villiers, J. M. and Jackson, M. L. (1967) Cation exchange capacity variations with pH in soil clays: Soil Sci. Soc. Am. Proc. 31, 473–476.CrossRefGoogle Scholar
Egawa, T. (1964) Volcanic Ash Soils in Japan: Ministry of Agriculture and Forestry, Japanese Govt., Chap. 3, p. 27.Google Scholar
Fieldes, M. (1955) Clay mineralogy of New Zealand soils: Part II. Allophane and related mineral colloids: New Zealand J. Sci. Technol. 37B, 336–350.Google Scholar
Fieldes, M. (1966) The nature of allophane in soils —I. Significance of structural randomness in pedogenesis: New Zealand J. Sci. 9, 599–607.Google Scholar
Fripiat, J. J., Van Cauwelaert, F. and Bosmans, H. (1965) Structure of aluminum cations in aqueous solutions: J. Phys. Chem. 69, 2458–2462.CrossRefGoogle Scholar
Fripiat, J. J., Leonard, A. and Uytterhoeven, J. B. (1965) Structure and properties of amorphous silicoaluminas — II. Lewis and Brønsted acid sites: J. Phys. Chem. 69, 3274–3279.CrossRefGoogle Scholar
Furkert, R. J. and Fieldes, M. (1968) Allophane in New Zealand soils: Trans 9th Intern. Congr. Soil Sci. III, 133–141.Google Scholar
Gastuche, Marie-Claire and Herbillon, Adrien (1962) Etude des gels ďalumine: cristallisation en milieu désionisé: Bull. Soc. Chim. France 1404–1412.Google Scholar
Gastuche, M. C., Toussaint, F., Fripiat, J. J., Touillaux, R. and Van Meerssche, M. (1963) Study of intermediate stages in the kaolin-metakaolin transformation: Clay Min. Bull. 5, 227–236.CrossRefGoogle Scholar
Hsu, P. H. and Rich, C. I. (1960) Aluminum fixation in a synthetic cation exchanger: Soil Sci. Soc, Am. Proc. 24, 21–25.CrossRefGoogle Scholar
Hsu, P. H. and Bates, T. F. (1964) Formation of X-ray amorphous and crystalline aluminium hydroxides: Mineral. Mag. 33, 749–768.Google Scholar
Jackson, M. L. (1960) Structural role of hydronium in layer silicates during soil genesis: Trans 7th Intern. Congr. Soil Sci. 2, 445–455.Google Scholar
Jackson, M. L. (1963) Interlayering of expansible layer silicates in soils by chemical weathering: Clays and Clay Minerals 11, 29–46.Google Scholar
Kanno, I., Onikura, Y. and Higashi, T. (1968) Weathering and clay mineralogical characteristics of volcanic ashes and pumices in Japan: Trans 9th Intern. Congr. Soil Sci. III, 111–122.Google Scholar
Léonard, A., Suzuki, Sho, Fripiat, J. J. and De Kimpe, C. (1964) Structure and properties of amorphous silicoaluminas— I. Structure from X-ray fluorescence spectroscopy and i.r. spectroscopy: J. Phys. Chem. 68, 2608–2617.CrossRefGoogle Scholar
Leonard, A. J., Van Cauwelaert, F. and Fripiat, J. J. (1967a) Structure and properties of amorphous silicoaluminas—III. Hydrated aluminas and transition aluminas: J. Phys. Chem. 71, 695–708.CrossRefGoogle Scholar
Leonard, A. J., Semaille, P. N. and Fripiat, J. J. (1967b): Proc. Brit. Ceram. Soc., London, In press.Google Scholar
Milliken, T., Mills, G. A. and Oblad, A. G. (1950) The chemical characteristics and structure of cracking catalysts: Discussions Faraday Soc. 8, 279–290.CrossRefGoogle Scholar
Oblad, A. G., Milliken, T. H. Jr. and Mills, G. A. (1951) Chemical characteristics and structure of cracking catalysts: Advan. Catalysis III, 199–247.Google Scholar
Oblad, A. G., Milliken, T. H. and Mills, G. A. (1951): Rev. Inst. Franç. Pétrole Ann. Combust, Liquides 6, 343.Google Scholar
Poncelet, G. M. and Brindley, G. W., (1967) Experimental formation of kaolinite from montmorillonite at low temperatures: Am. Mineralogist 52, 1161–1173.Google Scholar
Saunders, W. M. H., (1965) Phosphate retention by New Zealand soils and its relationship to free sesquioxides, organic matter, and other soil properties: New Zealand J. Agr. Res. 8, 30–57.CrossRefGoogle Scholar
Takahashi, T. (1964) Aluminium in volcanic-ash soils. Changes in physico-chemical properties of soils by cultivation: Kyushu Nogyo, Shikensho Tho 10, 205246.Google Scholar
Tamele, M. W. (1950) Chemistry of the surface and the activity of alumina-silica cracking catalysts: Discussions Faraday Soc. 8, 270–279.CrossRefGoogle Scholar
Thomas, Charles L. (1949) Chemistry of cracking catalysts: Ind. Eng. Chem. 41, 2564–2573.CrossRefGoogle Scholar
Wada, K. and Matsubara, I. (1968) Differential formation of allophane, “Imogolite” and gibbsite in the Kitakami pumice bed: Trans 9th Intern. Congr. Soil Sci. III, 123–131.Google Scholar
White, E., McKinstry, H. and Bates, T. F. (1958) Crystal chemical studies by X-ray fluorescence: 7th Ann. Conf. X-ray Anal., Denver 2, 239–245, .Google Scholar