PREPARATION AND SEM-EDX-XRD CHARACTERIZATION OF MAGNETIC ZEOLITIC MATERIALS OBTAINED FROM COAL FLY ASH

摘要

A low-cost magnetic zeolitic material was synthesized from coal fly ash by means of a new, simple method involving alkaline hydrothermal zeolitization of fly ash (FA) followed by low-intensity wet magnetic separation. Scanning electron microscopy with energy-dispersive X-ray analysis was applied to characterize the composition, microstructure, and morphology of the material. The mineral and synthetic zeolite phases were identified by powder X-ray diffraction. The obtained magnetic zeolitic material (about 53 wt% of the raw fly ash) consisted predominantly of fly ash particles with moderate to high Fe content (10 - 60 wt%), covered with 2-3 mu m thick shell of zeolite A crystals with fine crystals of zeolite P on them. Small iron oxide particles captured in larger iron-lean ( 2 wt%) zeolitized FA particles were also present in the product. Occasionally, uncovered iron oxide particles were detected, as well. The obtained magnetic zeolitic material could be easily manipulated in water suspension by means of low-intensity magnetic field and has potential application as an adsorbent for the removal of water contaminants from large volume effluents.