Accelerated weathering of construction‐grade limestone for CO₂ absorption

Abstract Accelerated weathering of limestone (AWL) process efficiently captures CO 2 from point source emissions. However, despite achieving an outstanding capture efficiency of 73.51 %, lab‐grade (LG) limestone with 99.90 % CaCO 3 as an absorbent is costly ($2757.70/t), making commercialization of AWL impractical. This work delves into the viability of utilizing construction‐grade (CG) limestone (93.26% purity) for the AWL process facilitated by potable water in an absorption tower for post‐combustion capture. The result shows that CG limestone achieves comparable CO 2 capture efficiency of 8.0–74.68% and bicarbonate (Ca(HCO 3 ) 2 ) concentration of 0.63–3.10 mM compared with LG limestone. However, LG limestone has 0.29 mol CO 2 /mol CaCO 3 higher CO 2 absorption capacity and a faster absorption rate than CG limestone, indicating a somewhat better CO 2 capture performance. Nevertheless, CG limestone offered a more cost‐effective alternative, with a $2735.24 lower cost per ton of CaCO 3 and a $2651.63 per ton CO 2 lower CO 2 capturing cost at the highest carbon capture efficiency (HCCE) condition compared to LG limestone. The kinetic analysis shows that the forward reactions in the AWL process are significantly faster at elevated CO 2 concentration, with the mass transfer coefficient affirming that CO 2 dissolves faster than CaCO 3 , in line with prior research. Thus, this work validates that CG limestone‐based AWL achieves comparable CO 2 capture performance to that of LG limestone, offering a cost‐efficient alternative. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.