Investigation of heavy metal partitioning influenced by flue gas moisture andchlorine content during waste incineration
Qinghai Li , Aihong Meng , Jinyan Jia , Yanguo Zhang
DOI:
Received July 17, 2009,Revised January 18, 2010, Accepted , Available online
Volume 22,2010,Pages 760-768
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The impact of moisture on the partitioning of the heavy metals including Pb, Zn, Cu and Cd in municipal solid waste (MSW)
was studied in a laboratory tubular furnace. A thermodynamic investigation using CHEMKIN software was performed to compare
the experimental results. Simulated waste, representative of typical MSW with and without chlorine compounds, was burned at the
background temperature of 700 and 950°C, respectively. In the absence of chlorine, the moisture content has no evident effect on the
volatility of Pb, Zn and Cu at either 700 or 950°C, however, as flue gas moisture increasing the Cd distribution in the bottom ash
increased at 700°C and reduced at 950°C, respectively. In the presence of chlorine, the flue gas moisture reduced the volatility of Pb,
Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides, and the reduction became
significant as chlorine content increase. For Cd, the chlorine promotes its volatility through the formation of more volatile CdCl2. As a
result, the increased moisture content increases the Pb, Zn, Cu and Cd concentrations in the bottom ash, which limits the utilization of
the bottom ash as a construction material. Therefore, in order to accumulate heavy metals into the fly ash, MSWshould be dried before
incineration.
