[Thermal analysis and the distribution rule of heavy metals during electroplating sludge combustion]

A representative hazardous waste containing heavy metal is electroplating sludge, Thermal characteristic and the distribution of different heavy metal elements (Pb, Cd, Cu, Zn, Ni and Mn) was studied. The results of experiment show that from thermal analysis, in the process of experiment of thermal gravity there are some peaks of weight loss as 100 degrees C, 150 degrees C and 600 degrees C among these peaks, the peaks of 100 degrees C and 150 degrees C is caused by that the volatile separated out and organic matter combusted and pyrolysed at the same time, the peak of 600 degrees C is produced by the carbonate decomposed. From EDS analysis, electroplating sludge is composed by these main elements which are O, S, Al, Ca, Cr and Fe, and other secondary elements such as Mg, Cu, Zn, P, Cl and C. In the process of temperature promoted, the quantity of nonmetal such as C and Cl is decreased, and the quantity of Cr, Fe, and Mg is steady within 900 degrees C. From the experiment of distribution rule, the quantity of Mn, Pb, Ni and Cu decreased in the process of combustion while the furnace temperature raised,among these heavy metal the quantity of Ni decrease most obviously,and on the contrary the quantity of Cd enrich obviously in this process.