Application of thermal plasma to vitrify fly ash from municipal solid waste incinerators

Several fly ash samples collected from different municipal solid waste incinerator plants were vitrified using thermal plasma furnace at 1400–1500 °C. After vitrification, there are obvious changes in microstructures and crystalline phases between produced slag and original ash. Toxicity characteristic leaching procedure results show that there is an excellent resistance against leaching of heavy metal ions. The residual fractions of heavy metals in slag presumably decrease in the following sequence: Cr > Ni > Cu > Zn > Pb > Cd. Almost all of PCDD/Fs could be destroyed through thermal plasma treatment. And the average decomposition efficiency of the samples vitrified by thermal plasma furnace is 100% in toxic equivalent calculations, higher than that of the samples vitrified by conventional resistance furnace.