Experimental Study on Melting of Hospital Waste Incineration Ash by Electric Arc Furnace
电弧炉熔融医疗垃圾焚烧灰的实验研究

The pilot-scale melting experiment of hospital waste incineration ash using a 2 kg DC electric arc furnace was carried out. The melting characteristics of bottom ash alone, and a mixture of bottom ash with bag fly ash were examined in terms of chemical composition, mineralogy, morphology, leaching behavior and residual fraction of heavy metals. The experimental results indicate that the bottom ash mainly consists of silicates, and major crystalline phases of bag fly ash are CaSO4 and NaCl, two kinds of melted slag are single-phase amorphous, glassy product. Volume reductions of two slags in comparison to the bottom ash and mixed ash respectively reach 78% and 80.5%. The Pb, Cd and Zn leaching concentrations of bag fly ash far exceed the hazardous waste landfill regulatory thresholds, the obtained slag is environmentally acceptable, possibly because heavy metals in the slag are combined into the Si-O network by the melting process. Residual fractions ofPb, Cd and Zn in two slags are low, and residual fraction of heavy metals in sample SLAG2 is lower than that in sample SLAG1.