Effect of Mineral Compositions on Volatilization of Pb during Coal Combustion

Abstract

Coal-red power plants are the main sources of atmospheric Pb. The mineral composition of coal is an important factor of the trace element distribution. The Pb volatilization characteristics of the anthracite, lignite and bitumite were examined in the horizontal tube furnace. SiO 2 , Al 2 O 3 , CaO and Fe 2 O 3 were chosen as the mineral compositions and PbO was chosen as Pb source to investigate the e ect of minerals on Pb volatilization during coal combustion. The results indicated that the occurrence modes of Pb and mineral composition were major factors in Pb volatilization and the coal containing more silicon and aluminum had the lower Pb volatilization rate. The intrinsic minerals in coal immobilized the released Pb through both physisorption and chemisorption. The combustion and thermogravimetric investigation showed that the Pb capture e ciency of the four minerals ranked as SiO 2 >Al 2 O 3 >CaO>Fe 2 O 3 . The formation of the non-volatile materials such as PbSiO 3 , Ca 2 PbO 4 and PbFe 12 O 19 accounted for the capture mechanisms of SiO 2 , CaO and Fe 2 O 3 , while Al 2 O 3 stabilized Pb via the physisorption. The synergy of SiO 2 and Al 2 O 3 exhibited the most superior capture e ciency on Pb, which provided references to the preparation of oriented Pb removal adsorbent.