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mineral carbonation, precipitated calcium carbonate, hydrothermal conversion, zeolitic materials, blast furnace slag, valorization


A three-stage process was developed to transform blast furnace slag (BFS) into two valuable products: precipitated calcium carbonate (PCC) and zeolitic materials. The conceptualized process aims to simultaneously achieve sustainable CO2 sequestration and solid waste elimination. Calcium is first selectively extracted by leaching with an organic acid, followed by carbonation of the leachate to precipitate CaCO3. In parallel, the hydrothermal conversion of the extracted solid residues in alkali solution induces the dissolution/precipitation mechanism that leads to the formation of micro- and meso-porous zeolitic materials. Leaching selectivity was identified as a key factor in the valorization potential of both products. Acetic acid satisfactorily limited the leaching of aluminium, required for the subsequent synthesis of zeolites, and carbonation of the acetic acid leachate resulted in the production of PCC of varied mineralogy and morphology, depending on processing conditions. In the hydrothermal conversion stage, the formation of zeolitic phases was observed, and their characteristics were found to vary depending on the calcium extraction efficiency in the previous stage, and the alkali (NaOH) concentration. The zeolitic phases produced, in order of increasing valorization potential, were: tobermorite, sodalite, lazurite, and analcime.


9 November 2016: At the time of publication, Sheridan College author Rafael M. Santos was associated with the Katholieke Universiteit Leuven in Belgium.


Faculty of Applied Science & Technology


School of Chemical and Environmental Sciences


Chemical Engineering Journal



Peer Reviewed/Refereed Publication


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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Original Publication Citation

Chiang, Y. W., Santos, R. M., Elsen, J., Meesschaert, B., Martens, J. A., & Van Gerven, T. (2014). Towards zero-waste mineral carbon sequestration via two-way valorization of ironmaking slag. Chemical Engineering Journal, 249, 260-269. doi:10.1016/j.cej.2014.03.104