ISSN:
1588-2837
Keywords:
Cancrinites
;
Sodalites
;
disordered aluminosilicates
;
crystallization kinetics
;
MAS NMR
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract During low temperature hydrothermal alkaline conversion of kaolinite in the presence of sodium carbonate a disordered phase crystallizes showing structural features between the sodalite and cancrinite minerals. A detailed study of its formation field and the kinetics of crystallization is the first step for further investigations of this zeolite-like material. The crystallization kinetics was investigated in the early stage of the reaction for times up to 192 h at a temperature of 353 K. Besides X-ray powder diffraction27Al MAS NMR has been found to be the preferred method to follow the reaction kinetics because a signal assigned to six-coordinated aluminium of the starting kaolinite can be clearly distinguished from a second resonance, being typical for aluminium in four-coordinate position of an aluminosilicate framework structure. Important conclusions can also be drawn from the experiments for the synthesis of ideal ordered cancrinites.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02475312
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