Abstract:
The tube furnace was selected as the combustion reactor, the actual domestic waste was used as the raw material. The heavy metal content was measured by inductively coupled plasma atomic emission spectrometer (ICP-AES), and the surface morphology of diatomite before and after incineration was observed by the field emission electron microscope (FE-SEM). The influence of diatomite on the migration characteristics of heavy metals Pb, Cd, Cu and Zn in the waste incineration process at different temperatures (600、700、800、900 ℃) and addition mass fraction (1%, 2%, 3%, 4%) was investigated in this paper. And HSC Chemistry 6.0 was used for thermodynamic simulation calculations. The experimental results showed that diatomite could make heavy metals more distributed in the bottom ash. With the increase in the amount of addition, the adsorption of heavy metals by the diatomite gradually increased. When the experimental incineration temperature was between 600−800 ℃, the adsorption efficiency of diatomite for heavy metals was as follows: Cd> Zn> Pb> Cu; at 900 ℃: Cd> Pb> Zn> Cu. The corresponding temperature of the best adsorption efficiency for Pb was 900 ℃, for Zn was 800 ℃, and for Cd and Cu were 700 ℃. Thermodynamic simulation found that diatomite could react with Pb, Cd, Zn to form corresponding silicates, and had no effect on the morphological changes of Cu. Combined with thermodynamic equilibrium simulation and experimental data analysis, physical adsorption and chemical adsorption coexisted in the adsorption of Pb, Cd and Zn by diatomite, and physical adsorption was the main adsorption for Cu.