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 mgCO(2) 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.