The effects of FeCl3 on the distribution of the heavy metals Cd, Cu, Cr, and Zn in a simulated multimetal incineration system

Recognizing that waste-derived chlorine can enhance heavy metal emissions b y forming volatile metallic chlorides during municipal solid waste (MSW) co mbustion, and that in Taiwan, FeCl3-containing sewage sludge may either be landfilled or coincinerated with other MSW, this study thus investigated th e effects of FeCl3 on the speciation and partitioning of heavy metals in a multimetal incineration system by using a tubular furnace and FeCl3-spiked simulated wastes. The molar ratio of chlorine content to heavy metal conten t (referred to as the Cl/ M ratio), ranging from 3 to 200, was used as a pa rameter to evaluate the effects of chlorine on the movement of heavy metals between the incinerator discharges. Results indicate that speciation and p artitioning were related to the affinity between the chlorine and the heavy metals and between chlorine and hydrogen in the combustion system. The eff ectiveness of increasing the Cl/M ratio to the formation potential of metal lic chlorides and on the shift of heavy metals from the bottom ash to the f ly ash and/or the flue gases was found to have in increasing order as follo ws: Zn>Cu>Cr, a phenomenon basically reflecting the volatility of the heavy metals and their chlorides formed during combustion. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.