Abstract
One of the most promising technologies for reducing volatile metal emissions from the waste incineration process is the high-temperature capture of vapor-phase metals before their condensing into fine particles. Packed bed sorption experiments for the capture of gaseous cadmium and lead using calcined kaolin particles were performed in a temperature range of 973-1,173 K. A calcined kaolin particle is composed of 2–3 im grains separated by large pores, through which the cadmium and lead vapor easily diffuse. Cadmium and lead react with sorbent to form waterinsoluble metal-mineral complexes (PbAl2Si2O8, CdAl2Si2O8 and Cd2Al2Si2O9). An increase in bed temperature results in an increase of capturing rates, but it has no effect on maximum uptakes for both metals. The diffusional resistance developed in the interior of the porous kaolin particles became limiting only after the conversion of metakaolinite reached a value of 50% or higher. The order of reaction with respect to the gas-phase concentration was determined to be 1.67 and 3.26 for lead and cadmium, respectively. The activation energy, Ea, was estimated to be 10.16 and 5.56 kcal/mol for lead and cadmium, respectively.
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Yang, HC., Yun, JS., Kang, MJ. et al. Mechanisms and kinetics of cadmium and lead capture by calcined kaolin at high temperatures. Korean J. Chem. Eng. 18, 499–505 (2001). https://doi.org/10.1007/BF02698297
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DOI: https://doi.org/10.1007/BF02698297