Improvement of Ash Surface-Melt Furnace and Utilization of the Slag

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Table 4 Analysis of Slag and Dust Item Si02 A1203 FeA CaO Mg Na K Zn Pb Cd CI Unit Of ,0 % % % % % % % % nig/kg % Bottom Ash Slag 45.7 20.9 3.6 10.5 1.4 2.5 1.0 0.67 0.06 <0.01 1.1 Dust 46.4 10.4 0.96 0.04 0.13 2.1 2.6 13.4 1.6 0.03 10.1 Fly Ash Slag 38.7 17.5 2.9 26.3 2.01 1.91 0.55 0.29 0.05 9 0.63 Dust 30.0 5.72 1.20 1.02 0.07 10.7 9.85 4.71 2.39 400 26.3 5 . 2 Leaching Test Result Table 5 shows the results of leaching tests of slag and fly ash from melting. The slag did not show elution in excess of the leaching standard of landfills. However, the fly ash from melting resulted in C d and Pb in excess of the standard, as it contains heavy concentration of these materials. Proper detoxification is needed. At present, solidifying by cement, and treatment by chemicals are considered best, but useful recovery of heavy metals should also be studied in the future. Table 5 Leaching Test of Slag and Dust Item Cd Pb As T-Hg Cr6* Unit mg/1 mg/1 mg/1 mg/1 mg/1 Bottom Ash Slag <0.01 <0.05 <0.02 <0.0005 <0.1 Dust 17 16 <0.02 <0.0005 <0.1 Bottom Ash + Fly Ash Slag <0.01 <0.05 <0.02 <0.0005 <0.1 Dust 39 170 <0.02 0.27 <0.1 12