For revealing the effect of calcium on heavy metal in-furnace capture by kaolinite,gaseous PbCl_(2) and CdCl_(2) adsorptions by calcium-doped kaolinite at high temperatures and their mechanisms were investigated throu...For revealing the effect of calcium on heavy metal in-furnace capture by kaolinite,gaseous PbCl_(2) and CdCl_(2) adsorptions by calcium-doped kaolinite at high temperatures and their mechanisms were investigated through experiments in a fixed-bed furnace,where factors of temperatures and the mixing proportion of limestone and kaolinite were considered.The results show that the adsorption efficiency of cadmium by the mixed sorbents is lower than that by single sorbents,mainly due to the consumption of lime or limestone,whereas that of lead varies at different reaction temperatures.Two kinds of areas,named as Ca-rich zone and Ca-low zone,are found in the sorbents of calcium-doped kaolinite.The Ca-rich zone tends to lessen the capture efficiencies for the two metals,whereas the Ca-low zone can enhance their adsorption.The heterogeneous distributions of calcium have multiple effects on metal sorption,including the diffusion enhancement through the eutectic effect by forming low-melting-point substances,the inhibition by the competitive occupation of reaction sites,and the block of pores caused by sintering at a high temperature.展开更多
基金The National Natural Science Foundation of China(No.51976036)the Scientific Research Foundation of the Graduate School of Southeast University(No.3203009748)。
文摘For revealing the effect of calcium on heavy metal in-furnace capture by kaolinite,gaseous PbCl_(2) and CdCl_(2) adsorptions by calcium-doped kaolinite at high temperatures and their mechanisms were investigated through experiments in a fixed-bed furnace,where factors of temperatures and the mixing proportion of limestone and kaolinite were considered.The results show that the adsorption efficiency of cadmium by the mixed sorbents is lower than that by single sorbents,mainly due to the consumption of lime or limestone,whereas that of lead varies at different reaction temperatures.Two kinds of areas,named as Ca-rich zone and Ca-low zone,are found in the sorbents of calcium-doped kaolinite.The Ca-rich zone tends to lessen the capture efficiencies for the two metals,whereas the Ca-low zone can enhance their adsorption.The heterogeneous distributions of calcium have multiple effects on metal sorption,including the diffusion enhancement through the eutectic effect by forming low-melting-point substances,the inhibition by the competitive occupation of reaction sites,and the block of pores caused by sintering at a high temperature.
