Study of the structure and thermal behaviour of intercalated kaolinites

Abstract

Intercalation complexes of three different Hungarian kaolinites with hydrazine and potassium acetate were investigated by FT-IR (DRIFT) spectrometry, X-ray diffraction, and thermogravimetry combined with mass spectrometry. Differences were found in the thermal behaviour of the complexes as well as in the rehydration -reexpansion patterns of the heated intercalates. An XRD method is proposed for the distinction of kaolinite and 7.2 A halloysite present in the same mineral.

Covalent Grafting of Phenylphosphonate Groups onto the Interlamellar Aluminol Surface of Kaolinite

“…Due to the observed interplanar distances (d ϭ 4.35, 4.29, 4.13, 3.52, and 2.52 Å), the crystalline form can be indexed as AlPO 4 and SiO 2 .…”

“…Examples of kaolinite intercalation usually involve the use of small polar molecules, typically dimethyl sulfoxide, n-methylformamide, and hydrazine (2)(3)(4). In spite of the fact that these materials have been known for many years, only recently have some mechanisms of these reactions been proposed, although the information concerning the exact positioning of the intercalated molecules is merely speculative.…”

“…Kaolinite (K, Al 2 Si 2 O 5 (OH) 4 ) is a dioctahedral 1:1 layered aluminosilicate, constituted by two different interlayer surfaces. One side of the lamella is made of a gibbsite-type layer with aluminium atoms coordinated octahedrally by oxygen atoms and hydroxyl groups.…”

Esfoliação e hidratação da caulinita após intercalação com uréia

“…concentrado na caracterização e consequentemente localização dessas moléculas intercaladas [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] , além da intercalação de algumas moléculas específicas que possam ser substituídas por outras, não diretamente intercaláveis [32][33][34][35][36] (método do deslocamento). Uma das maneiras desenvolvidas recentemente, envolve o uso da caulinita hidratada que pode ser preparada tratando-se a caulinita organofuncionalizada, com álcoois ou água [37][38][39][40] .…”

Thermal Decomposition of a Dickite-Hydrazine Intercalation Complex

“…Intercalation of hydrazine in the interlayer of kaolin minerals has been extensively studied by X-ray diffraction (XRD) and spectroscopic methods (Weiss et al, 1963;Ledoux and White, 1966;Wada and Yamada, 1968;Range et al, 1969;Jackson and AbdelKader, 1978;Theng et al, 1984;Johnston, 1990;Johnston and Stone, 1990;Gfibor et aL, 1995;Frost et aL, 1998;Kloprogge et al, 1999;Krist6f et al, 1997Krist6f et al, , 1999Ruiz Cruz and Franco, 2000). Most of these studies involve the kaolinite-hydrazine (K-H) complex, and especially the characterization of kaolinites with various degrees of lattice disorder (e.g., Range et al, 1969;Fernfindez Gonzfilez et al, 1976;G~ibor et al, 1995;Kloprogge et al, 1999), whereas the dickitehydrazine (D-H) and nacrite-hydrazine (N-H) complexes have received less attention.…”