PREPARATION AND APPLICATION OF POROUS MATERIALS BY COMBINING BASE AND ACID MODIFICATION OF KAOLIN

Abstract

Abstract: The effect of modification of fully calcined kaolin with different alkaline concentration, different alkaline treating times, and acid treating of alkaline-leaching fully calcined kaolin was studied in details. The changes in porosity, chemical composition of modified fully calcined kaolin were characterized by XRD, N₂ adsorption-desorption and X-ray fluorescence spectrometer. The results showed that with the increase of alkaline solution concentration, the pore volume and BET surface area of the modified product increased, and the SiO₂/Al₂O₃ ratio reduced slightly, but with the increase of alkaline-treated times, the pore volume decreased and SiO₂/Al₂O₃ ratio increased. Moreover, the porous material with a pore volume of 0.81 cm³/g and a specific surface area of 408 m²/g could be obtained after alkaline-leaching fully calcined kaolin further modified by acid treating. When using the catalyst prepared from the porous material for catalytic cracking reaction,the slurry yield reduced by 3.07 percentage points, the gasoline yield increased by 2.68 percentage points, and the total liquid yield increased by 2.58 percentage points.

Key words: kaolin, porous material, alkali modification, acid modification, catalytic cracking

References

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