FORMATION OF HEAVY METAL SPECIES DURING PVC-CONTAINING SIMULATED MSW INCINERATION

Abstract

The effect of PVC-derived chlorine on heavy metal emissions in MSW incineration was investigated using a tubular furnace and simulated MSW spiked with PVCs and heavy metals (Cd, Cr, Cu, and Zn). The molar ratio of the chlorine content to that of the heavy metal (Cl/M ratio) was varied from 3–200 as one parameter. The results indicated that the major species found in the fly ash were chlorides of alkaline and alkali-earth metals, whereas those identified in the bottom ash were MgSiO₃, SiO₂ and some complex aluminates and silicates. The emission of heavy metals and/or their compounds, with extreme and medium volatility, tended to be enhanced within the lower Cl/M range, whereas those with a refractory volatility were likely to be affected within the higher Cl/M range. However, those with an extremely refractory volatility were less affected by an increase of the Cl/M ratio. The variation of speciation and partitioning in MSW combustion as affected by the Cl/M ratio are discussed.

Keywords:

• Heavy metal
• MSW incineration
• Partitioning
• Speciation

ACKNOWLEDGMENT

The authors would like to acknowledge funding for this study provided by the National Science Council of the Republic of China under Project No. NSC-87-2218-E-264-002.