Atmospheric carbon capture performance of legacy iron and steel waste

Mayes, William M.

Abstract

Legacy iron (Fe) and steel wastes have been identified as a significant source of silicate minerals, which can undergo carbonation reactions and thus sequester carbon dioxide (CO2). In reactor experiments, i.e., at elevated temperatures, pressures, or CO2 concentrations, these wastes have high silicate to carbonate conversion rates. However, what is less understood is whether a more “passive” approach to carbonation can work, i.e., whether a traditional slag emplacement method (heaped and then buried) promotes or hinders CO2 sequestration. In this paper, the results of characterization of material retrieved from a first of its kind drilling program on a historical blast furnace slag heap at Consett, U.K., are reported. The mineralogy of the slag material was near uniform, consisting mainly of melilite group minerals with only minor amounts of carbonate minerals detected. Further analysis established that total carbon levels were on average only 0.4% while average calcium (Ca) levels exceeded 30%. It was calculated that only ∼3% of the CO2 sequestration potential of the >30 Mt slag heap has been utilized. It is suggested that limited water and gas interaction and the mineralogy and particle size of the slag are the main factors that have hindered carbonation reactions in the slag heap.

• Journal Article Type: Article
• Journal: Environmental Science & Technology
• Print ISSN: 0013-936X
• Electronic ISSN: 1520-5851
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 53
• Pages: 9502-9511
• APA6 Citation: Pullin, H., Bray, A. W., Burke, I. T., Muir, D. D., Sapsford, D. J., Mayes, W. M., & Renforth, P. (in press). Atmospheric carbon capture performance of legacy iron and steel waste. Environmental Science and Technology, 53, 9502-9511. https://doi.org/10.1021/acs.est.9b01265
• DOI: https://doi.org/10.1021/acs.est.9b01265
• Keywords: General Chemistry; Environmental Chemistry
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.est.9b01265
• Additional Information: The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.est.9b01265.