Characteristics of Molten Slag from Hospital Waste Incineration Ash by Electric Arc Furnace

To deal with the issue of hospital solid waste (HSW) incineration ash, ash melting treatment technology was developed in combination with electric arc furnace metallurgical processes. The lab-scale melting experiment of HSW incineration ash, using 2kg DC electric arc furnace, was carried out to provide physical and chemical property analyses of molten slag from the bottom ash alone and the mixture of fly ash and bottom ash. The results show that the reduction volume rates of molten slag all reached about 80%, heavy metals mainly exist as the residual fraction, and the leachability of heavy metals is extremely low, completely meeting the requirements of environmental protection. Water-cooled slag is non-crystalline amorphous glassy lava, whereas air-cooled slag is anorthite crystal (Ca₂Al₂SiO₇) and its heavy metals exist more as carbonate fraction. The electric arc furnace for incineration ash melting should adopt the water-cooled approach to discharging slag for best.