Migration and Distribution of Heavy Metals During Co-combustion of Sedum plumbizincicola and Coal

Co-combustion is considered one of the most promising disposal techniques for Sedum plumbizincicola and coal. However, the distribution of heavy metals (Cd, Zn and Pb) in this incineration is still not determined. Tube furnace experiments were conducted to investigate the effects that burning temperature, atmosphere and mixing ratio impacted on the distribution of heavy metals. XRD analysis was performed to study the speciation characteristics of heavy metals in bottom ash. The results indicate that high temperature is beneficial to the volatilization of heavy metals with the order of Pb > Cd > Zn. With increasing oxygen content, the distribution of Zn and Cd in bottom ash is more, while Pb concentration is initially increased and then decreases. Increase in the proportion of S. plumbizincicola is not conducive to the stabilization of Zn and Pb, but is conducive to the disposal of Cd. The calculation results of HSC Chemistry demonstrate that increasing temperature significantly increases the volatilization of Cd and Pb in the form of Cd (g) and PbO (g). In oxygen atmosphere, Zn exists in the form of heavy metal oxides, not easy to volatilize. Under anaerobic condition, Zn begins to volatilize as Zn (g) and oxygen is not conducive to the volatilization of Zn. The co-combustion in air condition is proved to be beneficial to the disposal of heavy metals.