Pore structure and possibility of fine dust removal for bottom ash sand

In this study, bottom ash sand was classified into sizes of 0.15 mm or less, 0.15∼0.6 mm, 0.6∼1.2 mm, 1.2∼2.5 mm, and 2.5∼5 mm by sand size. The results were evaluated with regard to fine dust removal. The bottom ash sand showed hysteresis in the adsorption and desorption of nitrogen gas, and the pore size was mostly over 100 nm as found by MIP measurement. As the size of bottom ash sand decreased from 0.6 mm, pore volume tended to increase. For this reason, when bottom ash sand is crushed to 0.6 mm or less, it is determined that the pore volume increases by converting closed pores into open pores. However, bottom ash sand of 0.6 mm or less is composed of pores of 10 μm or more, which are mostly used as fine dust passages, and thus the effect of removing fine dust is low. Bottom ash sand of 0.6 mm or more is composed of pores of 0.1 μm or more, which are considered to be effective in removing PM2.5 and PM10. In particular, the ratio of pores with sizes of 0.1∼2.5 μm, capable of removing PM2.5, is 56.1∼74.8%, which is expected to be effective at removing PM2.5.