Kaolin-based zeolite Y, a precursor for cordierite ceramics

Kaolin is a convenient Si–Al source for synthesizing low silica zeolites such as A, X and Y. Magnesium-exchanged zeolite Y with appropriate chemical composition can be an ideal precursor for cordierite. The present work reports a systematic study on the synthesis of zeolite Y from kaolin, conversion to MgY by ion exchange and sintering of the latter to get cordierite. Characterization of the intermediate and products by XRD analysis optimized the reaction conditions for zeolite formation. Selected samples were studied by solid-state NMR (29Si and 27Al) and IR spectroscopy, SEM and chemical analyses. Properties like surface area and sorption capacity were also measured. MgY zeolite was heat treated at different temperatures, and the products were analyzed. Cordierite was formed at 1250 °C, which showed properties comparable to those of the product synthesized by conventional methods. The trace mineral impurities inherently present in the kaolin are mostly retained in the zeolite, and they influence the properties and sintering behaviour of the product.