The Detoxification of Medical Waste Incineration Fly Ash using Self-Propagating Reaction

This work describes the utilization of self propagating reaction for the detoxification of the fly ash from medical waste incineration. The immobilization of heavy metals and phase transformation fly ash were evaluated. In this self propagating process, the mix ratio of fly ash to the starting mixture of more than 80% will support the self propagating process with a melting temperature of 1400°C. The toxicity characteristic leaching procedure shows that the fly ash leaching concentration of Pb, Cd exceeds the toxicity regulation level of Hazardous Waste Characteristics, and the Cu and Zn are with relatively high environmental risk too. But for the self propagating product, Cu, Pb, Cd can barely be detective in the leachate. The detoxification can be attributed to the evaporation and the immobilization process, according to the experimental analysis, the unvolatilized part is fixed in the vitrified melt inclusion, and the heavy metal speciation transform into FeMn oxides, organic matter bound and residual forms. The results indicates that melting of fly ash by self propagating reaction can be a reliably way to decrease the risk to both environment and human.