Michiel Giels, Tobias Hertel, Thi Nhan Nguyen, and Yiannis Pontikes from KU Leuven have published a new study in the Journal of Sustainable Metallurgy that brings the fields of metallurgy and cement research closer together. The team demonstrates how iron-rich glassy materials derived from bauxite residue can act as a novel supplementary cementitious material (SCM) in blended cements.
Their case study focuses on vitrified bauxite residue (VBR), a product composed mainly of Al₂O₃–SiO₂–CaO–FeO–Na₂O. The VBR exhibits reactivity levels on par with common SCMs such as ground granulated blast furnace slag, and even shows properties comparable to calcined clays like metakaolin. Key innovations include the use of triisopropanolamine to boost reactivity and limestone additions to stabilise hydration and improve mechanical performance.
Importantly, VBR performed well in durability indicators—showing reduced drying shrinkage and alkali-silica reaction, as well as controlled release of heavy metals—making it a promising low-carbon cement ingredient. With iron widely available in natural and industrial residues, this work opens new circular pathways for Fe-rich materials in construction applications.
Reference:
Giels, M., Hertel, T., Nguyen, T.N., & Pontikes, Y. (2025). Bringing Metallurgy and Cement Industry Closer: Fe-rich Glass as a Supplementary Cementitious Material. Journal of Sustainable Metallurgy. https://doi.org/10.1007/s40940-025-00384-0
Acknowledgements:
This research was supported by KU Leuven and RWTH Aachen and contributes to SIM² KU Leuven’s mission of closing material loops through metallurgical and mineral processing innovation.
