Untersuchung der thermischen Zersetzung von Aluminium-dodekawolframatosilicat |
| |
Authors: | H-J Lunk M B Varfolomeev N B amraj D Müller W Hilmer |
| |
Institution: | H.-J. Lunk,M. B. Varfolomeev,N. B. ?amraj,D. Müller,W. Hilmer |
| |
Abstract: | Investigation on the Thermal Degradation of Aluminium-12-Tungstosilicate The dehydration of aluminium-12-tungstosilicate AlHSiO4W12O36] · 29 H2O gives the anhydrous salt at 440°C. By means of X-ray heating patterns, thermal analysis, and i.r. spectroscopy the formation of the new phase 1/2 Al2O3 · SiO2 · 12 WO3 (I) at 500°C is observed, stable at room temperature. Above 800°C from I tetragonal W3, Al2(WO4)3, and amorphous SiO2 are formed. Amorphous SiO2 crystallizes to high-temperature cristobalite at 1000°C. High-resolution 27Al NMR (MAS-technique) is used to determine the coordination number of aluminium in the different phases. |
| |
Keywords: | |
|
|