DC Arc Plasma Furnace Melting of Waste Incinerator Fly Ash

Municipal solid waste incinerator (MSWI) fly ash was melted using a set of direct current (DC) arc plasma furnace system for the first time in China. At a feed-rate of flying ash of 80 kg/h, the temperature at the gas outlet was above 1300°C. Dioxins in the off-gas were recorded as 0.029 ng I-TEQ/Nm3 (international toxic equivalent, I-TEQ), well below 0.5 ngTEQ/Nm3 (toxic equivalent, TEQ), while those in the melted product (slag) were 0.00035 ng/g I-TEQ. Molten slag from the furnace showed excellent resistance against the leaching of heavy metals. These results prove that the plasma furnace is effective for the detoxification and stabilization of MSWI fly ash.