[Effects of sulfur compounds on Pb partitioning in a simulated MSW incinerator]

The effect of sulfur compounds (including sulfur, sulfide, sulfite and sulfate), initial concentration of heavy metal and operating conditions on Pb emission in MSW incineration were investigated using a simulated tubular furnace with the simulated MSW. Operating conditions of the experiment included combustion chamber temperature and MSW residence time. The concentration of Pb was measured by ICP-AES after the digesting of samples including bottom ash, fly ash and flue gas according to related USEPA methods. The results indicated that all 4 sulfur compounds tended to increase Pb partitioning in fly ash and decrease Pb partitioning in bottom ash. The increasing of S and Na2S content tended to decrease Pb partitioning in bottom ash, meanwhile, the content of Na2SO3 and Na2SO4 have no significant effects on Pb partitioning. Incineration temperature showed a significant effect on Pb volatilization, and thus the Pb partitioning in fly ash increasing along with temperature went upwards. Pb did not partition in flue gas during the whole experimental temperature range. Furthermore, the effect of initial concentration of heavy metal had a significant influence on Pb partitioning. The more initial concentration of Pb was, the more Pb partitioned in bottom ash. MSW residence time was also investigated. The longer MSW residence time was, the less Pb partitioned in bottom ash.