Impact of Melt Phase Formation on the High-Temperature Behaviour of MgO–CMA–C Refractories

Christos G. Aneziris1, Christoph Wöhrmeyer2, Theresia Preisker3, Christopher Parr4, Patrick Gehre5

1 Institute of Ceramic, Glass and Construction Materials, Technical University Bergakademie Freiberg, 09599 Freiberg/Germany
2 Imerys Aluminates, Paris/France
3 Institute of Ceramic, Glass and Construction Materials, Technical University Bergakademie Freiberg, 09599 Freiberg/Germany
4 Imerys Aluminates, Paris/France
5 Institute of Ceramic, Glass and Construction Materials, Technical University Bergakademie Freiberg, 09599 Freiberg/Germany

Revision 10.07.2019, 22.07.2019

Volume 11, Issue 4, Pages 73 - 77

Abstract

Due to their excellent thermomechanical properties and corrosion resistance against aggressive steel/slag systems, carbon ­bonded magnesia (MgO–C), alumina ­magnesia (AMC), and magnesia ­alumina (MAC) bricks are the dominating refr actories for the lining of the side walls and bottom of steel ladles , basic oxygen furnaces, and electric arc furnaces. In order to further improve the properties to meet the requirements for even longer service life, highly reactive spinel­rich powder/aggregates (2,5 mass­%, 5 mass­%, and 7,5 mass­%) has been introduced in the composition consisting of common MgO-C in two different qualities with 3 mass­% C (after carbonisation), carbonised at 1400 °C. Melt phase formation is expected after carbonisation that could support the formation of a protective layer on the brick surface to protect the brick from slag penetration and the carbon from o xidation. Thus, the infuence of this melt phase formation on the thermomechanical properties has been studied. Besides the thermomechanical properties CCS, HMOR, apparent porosity, and median pore diameter, the phase composition after carbonisation has been analysed.

Keywords

refractories, ladle, MgO–C properties

References

[1] Figueiredo Jr., A.; et al.: Technological evolution of magnesia ­carbon bricks for steel ladles in Argentina. Iron and Steel Technology (2004) [1] 42–47 [2] Pagliosa, C.; Souza, P.V.; Hama, N.: Improvement of MAC bricks for steel ladle with CaO-MgO­-Al2O3 aggregate: A new perspective for cement application. Proc. UNITECR 2017, Santiago de Chile, 2017, 169–172 [3] Wöhrmeyer, Chr.; et al.: Protection mechanism of CMA­-additives in MgO-C ladle bricks. Proc. 61th Int. Colloquium on Refractories, Aachen, 2018, 54–59 [4] Gehre, P.; et al.: Untersuchung der Schutzwirkung von MgO-­C­ Pfannensteinen mit CMA­-Zusatz. Keram. Z. 70 (2018) 40–46 [5] Gehre, P.; et al.: Functional Spinel ­Binder Based Additives for Improved MgO-C Performance in Ladle Applications. refractories WORLDFORUM 9 (2017) [3] 83–88

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