Study on Migration Characteristics of Pb and Cu and Stabilization of Fly Ash During Incineration of Domestic Refuse

Abstract Heavy metals are important pollutants in the process of incineration of solid waste and pose a potential threat to the environment. In this paper, two heavy metals, Pb and Cu, were taken as the research objects, and their migration rules in the furnace refuse, slag, fly ash and flue gas were tracked and monitored respectively. The results showed that the concentration ratios of Pb and Cu in the slag and fly ash were 1:3.05 and 1:3.29, respectively, which were consistent with the furnace waste. No Cu was detected in the flue gas, but a small amount of Pb was present. XRF analysis shows that the CaO content in fly ash is 22.24%, Cl 6.64%, SO 3 12.28% and K 2 O 4.37%, and the CaO content in fly ash is significantly reduced. The content of Cl and SO 3 is 5.31 times and 2.97 times of the slag, respectively. The migration and storage of Cl and S promote the transformation of Pb and Cu. XRD analysis shows that the content of SO 2 , CaCO 3 , Ca(OH) 2 and SiCl 4 in slag is high. The high NaCl content in fly ash can promote the migration of Pb and Cu from slag to fly ash. Through leaching concentration monitoring and SEM analysis, the surface of fly ash was condensed from loose structure to flocculent structure after chelation, and the porosity was significantly reduced, and the leaching concentrations of Pb and Cu were reduced by 99.9% and 94.7% respectively, which greatly reduced the risk to the environment. The research results of this paper can provide reference for the harmless disposal and resource utilization of slag and fly ash in the incineration disposal of domestic waste.