Characteristics of selenium capture by typical Ca-/Mg-based sorbents

The characteristics of Se capture by CaO, CaCO₃, and MgO which are main components of Ca-/Mg-based mineral sorbents at 500-800 ℃ and that by calcite and dolomite were investigated, and the CaO obtained from calcine minerals were also used to capture Se. The results showed that capacity of CaO for Se capture was the highest, and the maximum value at 800 ℃ was 368 mg/g. Capacity of CaCO₃ on Se adsorption at 700 ℃ was the largest and thermostability of the used CaCO₃ was better. Se adsorption of Mg-based sorbents at medium temperature was obvious. The trend for Se adsorption capacity of calcite with increasing temperature was similar to that of CaCO₃. Effect of calcite on Se capture was better than that of CaCO₃, which was attributed to the higher specific surface area and pore volume of calcite. The ability of F-sor obtained from calcined calcite for Se capture was better than that of C-sor from calcined CaCO₃ as well as that of CaO, which was likely due to higher specific surface area and pore volume of F-sor. Moreover, the used F-sor showed better thermostability at higher temperature, and the maximum adsorption capacity of F-sor was 403 mg/g.