(00548)Conversion of coal fly ash by-products into high-grade zeolites by a quasi natural crystallization process

摘要

This study is focused on a technologically viable approach to obtain zeolite Na-X by aging of lignite coal fly ash (FA)in alkaline solutions at ambient conditions resembling a quasi natural crystallization process. Reaction products were characterized for their phase composition by X-ray diffraction, morphology by scanning electron microscopy (SEM)and surface properties by nitrogen adsorption/desorption isotherms. The effect of the crystallization time was investigated as an important parameter for the extent of zeolitization. The highest yield of zeolite Na-X was achieved by incubating FA in 1.5 mol/l NaOH for one year. However, significant crystallization extent is established after eight months of alkaline aging. Fly ash zeolites (FAZ)obtained by atmospheric crystallization have specific surface values up to 280 m~2/gFAZ.