Performance of steel slag in carbonation-calcination looping for CO2 capture from industrial flue gas

We investigate the performance of steel slag during the carbonation-calcination looping as a potential CO₂ adsorbent. The existence of portlandite in the steel slag provided a maximum theoretical CO₂ capture capacity of 112.7 mg_CO2 g _slag^-1, and the maximum carbonation conversion of 39.8% was achieved in simulated flue gases with only 5 min duration of carbonation. Sintering of the steel slag particles during both the carbonation and calcination processes, especially the destruction of the 3 nm pores, is the main cause for the deactivation of steel slag. Carbonation-calcination looping of steel slag can significantly improve its total CO₂ capture capacity compared to the conventional technical route of direct carbonation sequestration, thus providing an alternative and more feasible option for the use of alkaline industrial wastes to capture CO₂ from industrial sources, such as the iron and steel production facilities.