Accelerated carbonation and stabilization of BOF slag: data fitting relationship between particle size and CO2 sequestration

Abstract

Carbonation of BOF slag offers a promising solution to reduce f-CaO content and simultaneously capture CO2. This study investigated the influence of particle size on f-CaO consumption and CO2 sequestration of BOF slag while exploring the kinetics of the carbonation process. Under optimum conditions, the finest particle size achieved f-CaO consumption and CO2 sequestration values reaching 99.72% and 5.57%, respectively; whereas the largest particle size exhibited values of 97.89% and 3.4%, respectively. The shrinking core model accurately described the carbonation process with internal diffusion identified as the rate-limiting step for the whole process. The transition point between two rate-limiting steps was determined along with an established equation between particle size, CO2 sequestration and time. The XRD patterns and SEM images illustrated morphological changes in slag before and after carbonation. These findings can provide crucial insights for optimizing the carbonation process and facilitating its utilization as cementitious materials.