Effects of Sulfur Compounds on Cd Partitioning in a Simulated Municipal Solid Waste Incinerator

The effect of sulfur compounds (including sulfur, sulfide, sulfite and sulfate), initial concentration of heavy metal and operating conditions on Cd emission in municipal solid waste (MSW) incineration were investigated using a simulated tubular furnace and simulated MSW spiked with Cd. The concentration of Cd was measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after digesting the samples including bottom ash, fly ash and flue gas according to related USEPA methods. The results show that S and Na2S tend to increase Cd partitioning in bottom ash, whereas Na2SO3 and Na2SO4 tend to reduce Cd partitioning in bottom ash. The effect of sulfur compounds on Cd partitioning in bottom ash was in the sequence of Na2 S > S > Na2SO3 > Na2SO4. chemical equilibrium analysis is also performed to determine the effect of sorbents on Cd adsorption. The calculations show that S presents strong affinity for Cd and restrains Cd adsorption by SiC2, whereas when temperature rises to between 830°C and 1030°C, Cd adsorption efficiency of SiO2 is over 80% and the efficiency of Al2O3 is up to 85%.