Study of calcium-based CO2 sorbent with high cycling stability derived from steel slag and its anti-sintering mechanism

In this research, steel slag was used as a calcium source to synthesize a calcium-based CO2 sorbent (Ca-S) with high sorption capacity and cycling stability. The results showed that the sorption capacity of the prepared Ca-S can reach 14.54 mmol/g under the optimal synthesis and sorption conditions, reaching 81% of the theoretical sorption capacity of CaO. Moreover, the cyclic sorption performance of the synthesized Ca-S was compared with that of commercial Ca(OH)2, and it was found that the Ca-S still maintained a higher stability than commercial Ca(OH)2 after 30 cycles. In order to further improve the sorption performance of CO2, Ca-S was doped with Na2CO3/ K2CO3. When the Na2CO3 loading amount was 3 wt%, the sorption rate of the sorbent was improved, and the sorption capacity was increased to 16.18 mmol/g, reaching 91% of the theoretical sorption capacity of CaO. Finally, the anti-sintering mechanism of Ca-S and the promotion mechanism of Na2CO3 were discussed. The results show that the calcium-based CO2 sorbent prepared from steel slag will have broad application prospects.