Fly ash from municipal solid wastes (MSW) incinerators in Korea contains a large amount
of toxic materials and requires pertinent treatments. However, since fly ash in Korea
has a high chlorine concentration, it is difficult to apply cementation and chemical
treatment techniques. In this study, we report the vitrification of fly ash along
with the properties of the glasses and leaching characteristics of heavy metal ions.
Fly ash can be vitrified by melting at 1500 degrees C for 30 min with the addition
of >5 wt.% of SiO2. Glasses showed Vickers hardness of 4000-5000 MPa, bending strength
of 60-90 MPa and indentation fracture toughness of approximately 0.9 MPa m(1/2). Glasses
also showed the excellent resistance against leaching of heavy metal ions with Cd2+
<0.04 ppm, Cr3+ <0.02 ppm, Cu2+ <0.04 ppm and Pb2+ <0.2 ppm. These results indicate
that the vitrification technique is effective for the stabilization and recycling
of toxic incinerator fly ash.