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For decades, refractories have played- and continue to play- a key role in industrialization. Think about it: we drive in cars, fly on airplanes, live and work in buildings made of concrete, glass, and steel, grow food using fertilizers, and heavily rely on plastics and fuels. All these everyday essentials are made possible, in part, using refractories in high-temperature industries like iron and steel, cement, glass, and petrochemicals.

However, refractories operate under some of the harshest conditions, including thermal shocks and corrosion, which lead to their premature failure or frequent need for vessel relining. While it is almost impossible to eliminate thermal shocks or corrosion entirely in industrial processes, the failure of refractories under a few thermal cycles is simply unacceptable.

As part of the push toward green steelmaking, my research seeks to reduce refractory consumption by developing refractories that are more sustainable and reliable in aggressive environments, particularly within steel ladles used in steel production. The core objective of this PhD project is to enhance the thermomechanical behaviour of refractories through microstructural fine-tuning.

Given that alumina is one of the promising materials capable of withstanding hydrogen-rich, reducing atmospheres, a key aspect in green steelmaking, this ongoing PhD investigates how different types of alumina aggregates influence the performance of alumina-based refractory castables. Specifically, the study focuses on tabular alumina and white fused alumina, two widely used aggregate types in refractories. Although both are high-purity alumina, they differ significantly in their physical properties, such as grain sizes and porosities, as well as crystallographic characteristics. These differences stem from their distinct processing routes: sintering for tabular alumina and fusion for white fused alumina. However, the impact of these differences on the overall thermomechanical performance of refractory castables is not yet fully understood.

Furthermore, with the use of these aggregates, we seek to induce microcracks within the refractory microstructure in a controlled and well-designed manner. The formation of these microcracks often results from the thermal expansion mismatches between the aggregate and matrix phases during the cooling stage after heat treatment. Well-designed and controlled microcracks are beneficial in achieving a “flexible” behaviour in refractory ceramics. Also, microcracks can act as crack arrestors, controlling crack propagation. With these possibilities, thermal shock resistance can be greatly improved in refractories, thereby reducing sudden and catastrophic failures in service.

This work is part of the CESAREF European consortium that focuses on driving sustainable refractory materials and processes in steelmaking. Available for any questions or suggestions, and do not hesitate to contact me if this research interests you. See you at the next ECerS Conference in Dresden!

Kwasi Boateng

kwasi.boateng@unilim.fr

IRCER / Imerys

Université de Limoges

Limoges, France

linkedin.com/in/kwasi-addo-boateng