Kinetics of carbonation reaction of basic oxygen furnace slags in a rotating packed bed using the surface coverage model: Maximization of carbonation conversion

The reaction kinetics of carbon dioxide (CO2) capture by the accelerated carbonation of basic oxygen furnace slag (BOFS) in a rotating packed bed (RPB) was evaluated using the surface coverage model. Experimental data were utilized to determine the reaction rate constants and maximum carbonation conversion of BOFS based on the surface coverage model. The results indicate that the carbonation of BOFS in an RPB can be well-expressed by the surface coverage model, with R2 values from 0.98 to 0.99. In addition, the results of reaction kinetics could be validated by observation of SEM and XEDS before and after carbonation, which indicates that the reacted BOFS was surrounded by the CaCO3 product. On the other hand, the reaction kinetics of steelmaking slag in an RPB was compared with that in various types of reactors, i.e., autoclave and slurry reactors. The overall rate of carbonation in an RPB (i.e., 0.299 min−1) was greater than that in both a slurry reactor (i.e., 0.227 min−1) and an autoclave reactor (i.e., 0.033 min−1). Furthermore, the maximum carbonation conversion of BOFS was initially determined by the results of the surface coverage model and then confirmed statistically by the response surface methodology (RSM). It was thus concluded that accelerated carbonation of BOFS in the RPB is a viable method due to its faster reaction kinetics under relatively milder reaction conditions. Accelerated carbonation of BOFS in the RPB is a promising process for CO2 capture due to its relatively higher carbonation conversion of BOFS within a shorter reaction time.