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