| abstract |
A method of synthesizing high-silica zeolites in a fluoride media using faujasite crystals as the aluminum source and quasi-siliceous seed crystals containing a small amount of germanium is described. The faujasite crystals dissolved during hydrothermal treatment, prior to the crystallization of LTA-type zeolites. High-silica zeolites of an LTA, a CHA, a *BEA and an STT-type were produced. High-silica zeolites with a Si/Al ratio (SAR) of 63 to 420 were synthesized, with the SAR related to the amount of faujasite crystals used. The aluminosilicate LTA-type zeolite products possess nearly defect-free structures, a characteristic often seen in fluoride mediated synthesis. The unit cell volumes of the high-silica LTA-type zeolites correspond to the amount of Al present in the framework. Aluminosilicate ITW-type zeolites were produced using these methods. |