Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 12 No. 2 April 2002|
zeolites from natural stellerite
（Materials Chemistry Lab, Nanjing University of Science and
Technology, Nanjing 210094，China）
Abstract:Y and P zeolites were synthesized hydrothermally from natural stellerite under different conditions and were characterized via XRD and FT-IR. The results show that the higher crystallinity of Y zeolite can be obtained in hydrothermal system with low alkalinity, low Ca2+/Na+ ratio, and high SiO2/Al2O3 ratio. The lattice space of the samples decreases as crystallization time increases. P Zeolite is prompted under condition of higher alkalinity and higher Ca2+/Na+ ratio. The intensity and number of bands in the range of 400cm-1～900cm-1 increases with reaction time. Bands at 680cm-1, 760cm-1 and 860cm-1 corresponding to Y zeolite appear during the crystallization stage. Most of these bands shift to higher wavenumbers when SiO2/Al2O3 ratio increases generally. In the hydrothermal system with reverse condition above, bands at 600cm-1, 420cm-1～470cm-1 hardly change as the crystallization time increases and the main crystal phase of P zeolite is obtained.
Key words: Y zeolite; P zeolite; stellerite; crystallinity; hydrothermal synthesis