CO2 capture performance of cement-modified carbide slag

A novel and low-cost synthetic CO2 sorbent for calcium looping process, cement-modified carbide slag (CMCS), was synthesized from carbide slag, aluminate cement and by-product of biodiesel by combustion. The effects of synthesis conditions such as combustion temperature, combustion duration, hydration, by-product of biodiesel and cement addition and regeneration temperature on CO2 capture performance of CMCS were investigated. The comprehensively optimum preparation conditions of CMCS were obtained. The highest CO2 capture capacity is 0.62 g/g after 10 cycles, which is 2.18 times as high as that of carbide slag. The addition of aluminate cement improves the CO2 capture performance of CMCS, while excessive aluminate cement is adverse for CO2 capture due to the reduced CaO content in CMCS. The addition of by-product of biodiesel contributes to a uniform sol mixing of carbide slag and cement. The CMCS exhibits higher carbonation and calcination rates than CS. The porous and stable pore structure leads to the better CO2 capture performance and cyclic stability of CMCS.