Impacts of Accelerated Carbonation on the Leaching of Harmful Elements in MSWIFA

Municipal solid waste incineration fly ash (MSWIFA) is a promising carbon sequestration material. However, the leaching behavior of harmful elements during the carbonation process is a problem that must be considered. This paper screened four different MSWIFAs to explore their physicochemical properties, the carbonation efficiency, and the leaching behavior of harmful elements. All of the MSWIFAs exhibited a relatively high carbonation efficiency (17.2-27%). The carbonation of MSWIFA effectively inhibited the leaching of Pb, Ba, and Se in the fly ashes. However, the leaching concentration of Cd in the carbonized fly ash increased instead. The leaching concentration of Cr in MSWIFA was not significantly affected by the carbonation reaction. With the addition of 5% CaO, not only was the carbonation efficiency of MSWIFA significantly improved (the efficiency increased by 16.6%), but also the leaching of harmful elements was greatly reduced, achieving the purpose of stabilizing MSWIFA.