In this study, as an alternative to the pure chemical used to prepare zeolite NaA, the clay mineral kaolinite was used as the source material for NaA-zeolite preparation. Kaolin has been utilized as an alternative cheap raw material for the synthesis of zeolite A via a two-step reaction; (1) dehydroxylation of kaolin at 900 °C to form an activated amorphous material known as metakaolin; (2) hydrothermal treatment of metakaolin with an aqueous alkali to form the zeolite. Before this reaction takes place, however, raw kaolin undergoes a pretreatment process to increase its purity through the removal of impurities. The present investigation deals with the preparation of zeolite A from refined kaolin. A series of composition and structural characterizations of both the starting material (kaolin) and the final product (zeolite A) were carried out using powder X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) to confirm the formation of NaA-zeolite. From the characterization studies, it was found that high-purity NaA-zeolite can be produced from local kaolin.
These findings enable us to answer the fundamental question regarding the structural characteristics of NaA-zeolites synthesized from Malaysian kaolin.
