Synthesis and characterization of 13X zeolite from low-grade natural kaolin

•13X zeolite was synthesized without extra Si source or dealumination.•Fused natural kaolin with NaOH, amorphous phase was obtained.•The BET surface area of the product was found to be 326 m2 g−1.

In this study, 13X zeolite was successfully synthesized from low-grade natural kaolin via alkali fusion followed by hydrothermal treatment, without extra Si source or dealumination. Fusion with NaOH, followed by hydrothermal reaction, kaolinite, illite and trace of quartz in kaolin sample were converted into zeolite. The effects of various factors during the synthesis process such as NaOH addition amount, crystallization time and temperature on the crystalline products were studied. The optimum synthesis conditions to get purity 13X zeolite were found to be alkali fusion of kaolin with the weight ration of NaOH/kaolin = 2.0 at 200 °C for 4 h, and crystallized at 90 °C for 8 h after homogenization by agitated at 50 °C for 2 h. The product was characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and N2 adsorption–desorption. The BET surface area of the product was found to be 326 m2 g−1. It can be concluded that the study provides the basic data and the process for extensive and efficient utilization of low-grade natural kaolin.

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