Characteristic and Leaching Behavior of Heavy Metals from Municipal Solid Wastes Incineration (MSWI) Fly Ash in Chongqing, China

An investigation was conducted on the characteristics and leaching behavior of heavy metals from municipal solid wastes incineration (MSWI) fly ash in Chongqing, China. Results indicated that the average particle size of the fly ash was 36.4 μm, the large particles were formed mainly by small particles´ adsorption or aggregation. The total content of the main heavy metals was about 1.04% of the fly ash, among which the contents of Zn, Pb, Mn and Cr were relatively high. Leaching concentrations of heavy metals in fly ash were influenced by the leaching procedure. The leaching concentrations of the heavy metals in fly ash determined by GB5085.3-2007 were all under the national standard limits. However, the leaching concentrations of Pb and Cd were 5.75 and 1.89 mg·kg^-1, respectively, both beyond the TCLP limits.