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YCN Newsletter 27 - Research in spot - Kwasi Boateng
Tailoring microstructures: Enhancing the thermomechanical properties of refractory castables
To attain the EU’s Net Zero 2050 goals, European steel industries, one of the most intensive carbon emitters, require a rapid transition into cleaner and more sustainable alternatives. Refractories, often called the hidden heroes, are ceramic materials specially engineered to withstand extreme heat while maintaining their strength and chemical stability.
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
IRCER / Imerys
Université de Limoges
Limoges, France
Latest news
2025 ECerS International Ceramist Student Exchange Program – 3rd call!
In the frame of the 2025 ECerS International Student exchange program, ECerS is opening a first call to allow grants to European Students to attend the 2025 International Symposium on Green Processing for Advanced Ceramics (IGPAC 2025), organised by the Ceramic Society of Japan, from 5th to 9th October 2025 in Ise-Shima/Mie, Japan.
Next Deadline to apply to the JECS Trust for Mobility projects is 31st August 2025!
Please note that the decisions of the JECS Trust board will not be known before end of October 2025. Activities submitted for the deadline of 31st August 2025 for support from the JECS Trust should then not begin before November 2025.
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