Hydrothermal Synthesis of Low Silica Zeolites From Natural Clays

Abstract

Synthetic low silica zeolites are used for adsorption based air separation processes. This work is devoted to find a cost saving method for the synthesis of low silica zeolites from clay sources as bentonite and kaolin. The bentonite sample has been activated by alkaline fusion and has been calcinated in Na₂CO₃ media to be used as reagent for the synthesis of low silica zeolites. The thermal transformation of kaolin extrudates to metakaolin and its alkaline fusion with bentonite constitutes a source for the crystallization of low-silica zeolites of A type. The morphologic and structural characterizations of synthesized materials have been done by scanning electron microscopy (SEM) and X-ray diffraction (XRD).