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.

Keywords:

• basic oxygen furnace slag
• carbonation reaction
• f-CaO consumption
• shrinking core model
• kinetic study

Acknowledgments

The authors gratefully acknowledge the financial support provided by National Natural Science Foundation of China, project No. 52074051, as well as the sponsorship from the Natural Science Foundation of Chongqing, project no. cstc2021jcyj-msxmX1111 and Fuling Science and Technology Project, project No. FLKJ,2022CBZ4061.

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This study was supported by National Natural Science Foundation of China, Natural Science Foundation of Chongqing and Fuling Science and Technology Project.