Emission of Cu, Zn and Cd from Coal in Songzao Coal Mine during the Process of Combustion

By taking the coal samples from seam K1, K2 and K3 of Songzao coal mine in Chongqing as the research objects. Total amount of Cu, Zn and Cd from coal samples and corresponding ash samples were studied. The content of Cu in coal from seam K1 and corresponding ash reach 152.25 and 51.71 mg/kg, while that of Cd in coal from seam K3 and corresponding ash are as low as 1.32 and 0.69 mg/kg, respectively. According to the relative enrichment factors, Cu is found to be the most volatile, while Cd is the least volatile heavy metal element. Relative enrichment factor of Cu in coal of seam K3 is as low as 15.93, while that of Cd in coal of seam K3 is as high as 67.68. By comparing the form content percentage of Cu, Zn and Cd in coal with that in their corresponding ash samples, Cu, Zn and Cd in coal from seam K1, K2 and K3 associated with the organic and sulfide fractions tend to vaporize in the process of coal combustion.