Functional Spinel-Binder Based Additives for Improved MgO–C Performance in Ladle Applications

Christoph Wohrmeyer1, Christopher Parr2, Patrick Gehre3, Christos G. Aneziris3

1 Kerneos GmbH, 46047 Oberhausen/Germany
2 Kerneos S.A., 92800 Puteaux/France
3 Institute of Ceramics, Glass and Construction Materials, Technische Universität Bergakademie Freiberg, 09599 Freiberg/Germany

Revision 02.05.2017, 18.05.2017

Volume 9, Issue 3, Pages 83 - 88

Abstract

Carbon bonded magnesia and magnesia-alumina bricks are used in the side walls and bottom of steel ladles for more than 30 years. They have to withstand aggressive steel/slag systems in the range of 1600–1750 °C and also provide an excellent thermal shock performance. During service or pre-sintering, alumina is able to react with magnesia to form spinel. In order to improve thermomechanical and chemical performance MA-spinel raw materials alumina-rich spinel and highly reactive spinel binder/clinker have been introduced in the composition. The impact of spinel or spinel forming phases on physical and thermomechanical properties as well as corrosion resistance has been found to depend on the grain size, chemistry, and amount of added raw materials. In order to implicate and reflect the influence of spinel formation on material properties the carbonization temperature has to be above common 1000 °C. Two different pre-reacted coarse- and fine-grained MA-spinel raw materials were added to common MgO–C with 3 mass-% C (after carbonization) and carbonized at 1000 °C and 1400 °C respectively. Thus, improved MgO–MgAl2O4–C samples with pre-reacted and in situ formed spinel for application in steel ladles were produced. Material properties like cold crushing strength (CCS) and thermal shock resistance, microstructure, and phase composition have been analysed.

Keywords

refractories, MgO–C, spinel, ladle

References

[1] Figueiredo Jr., A.; et al.: Technological evolution of magnesia-carbon bricks for steel ladles in Argentina. Iron and Steel Technology 1 (2004) 42–47 [2] Tripathi, H.S.; Ghosh, A.: Spinelisation and properties of Al2O3-MgAl2O4-C refractory: Effect of MgO and Al2O3 reactants. Ceramic Int. 36 (2010) 1189–1192 [3] Nourbakhsh, A.A.; et al.: Increasing durability of ladle lining refractories utilizing Al2O3-MgOC bricks. Proc. of the 8th Biennial Worldwide Conf. on Refractories (2003) 19–22 October 2003, Osaka, Japan [4] Choi, T.H.; Jun, B.S.: Wear mechanism of MgOC refractory with thermite reaction products of MgO and Al. J. of the Korean Ceram. Soc. 33 (1996) 832–838 [5] Xue, J.: Development and application of ultralow- carbon-containing MgO-MgAl2O4-C bricks for ladle slag line. Naihuo Cailiao 45 (2011) 107–109 [6] Ganesh, I.; et al.: An efficient MgAl2O4 spinel additive for improved slag erosion and penetration resistance of high-Al2O3 and MgO-C refractories. Ceramic Int. 28 (2002) 245–253 [7] Das, R.R.; et al.: Influence of nanocrystalline MgAl2O4 spinel addition on the properties of MgO-C refractories. Mater. and Manufacturing Processes 27 (2012) 242–246 [8] Wu, J.; et al.: Effect of CaAl4O7-MgAl2O4 on thermal shock resistance of low-carbon MgOC brick. Naihuo Cailiao 45 (2012) 440–442 [9] Wohrmeyer, C.; et al.: New spinel containing calcium aluminate cement for corrosion resistant castables. Proc. of the 12th Biennial Worldwide Conf. on Refractories (2011) 30. Oct. – 2. Nov. 2011, Kyoto, Japan, CD-ROM

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