Strength Evolution and Corrosion Resistance of a Cement-Free Al2O3-Castable Containing a Novel Hydraulic Binder Based on α-Alumina

Albrecht Wolter1, Christian Dunzen2, Oliver Splittgerber2

1 Technische Universitat Clausthal, Institut fur Nichtmetallische Werkstoffe, 38678 Clausthal-Zellerfeld/Germany
2 Nabaltec AG, 92421 Schwandorf/Germany

Revision

Volume 9, Issue 1, Pages 55 - 60

Abstract

An alternative no-cement-binder system based on reactive α-alumina and magnesia (NC-Binder) for the formulation of no cement castables has recently become commercially available under the brand name NABACASTR. A first paper has been published to describe its setting mechanism, and cold processing properties of castables containing NC-Binder [1], this second paper intends to illustrate the effect on high temperature properties of castables. It describes the use of a reactive α-alumina-magnesia mix as a binder for a no cement castable and compares the properties of this castable with the properties of an ultra low cement castable. Evolution of cold compressive strength after firing at different temperatures is monitored. Slag cup tests are conducted with slags of different basicity. The results are correlated with the sintered castable’s microstructure and chemical composition. Results are verified in an induction furnace test and a model of the corrosion principle is presented.

Keywords

NABACAST, no-cement castable, slag resistance

References

[1] Dunzen, C.; Wolter, A.: Setting behaviour and hydration mechanism of a novel cement-free binder system based on reactive α-alumina. Proc. of the 59th Int. Coll. on Refractories (2016) 94–98 [2 Petzold, A.; Ulbricht, J.: Feuerbeton und betonartige feuerfeste Massen und Materialien. Leipzig 1994 [3] Cardoso, F. A.; et al.: Drying behaviour of hydratable alumina-bonded refractory castables. J. of the Europ. Ceram. Soc. 24 (2004) 797–802 [4] Hart, L.D.: History of alumina chemicals. Alumina chemicals. Science and technology handbook. Westerville/OH 1990, 3–5 [5] Salomao, R.; Bittencourt, L.R.M.; Pandolfelli V.C.: A novel magnesia based binder (MBB) for refractory castables. Ceramic Monographs 2.6.9., Supplement to Interceram 60 (2011), 1–4 [6] Kriechbaum, G.; Gnauck, V.; Routschka, G.: The influence of SiO2 and spinel on the hot properties of high alumina low cement castables. Forschungsgemeinschaft Feuerfest, Bonn, Stahl und Eisen Special (1994) 150–159 [7] Berjonneau, J.; Prigent, P.; Poirier, J.: The development of a thermodynamic model for Al2O3- MgO refractory castable corrosion by secondary metallurgy steel ladle slags. Ceramics Int. 35 (2009), 623–635 [8] Diaz, L.A.; et al.: Effect of spinel content on slag attack resistance of high alumina refractory castables. J. of the Europ. Cer. Soc. 27 (2007) 4623– 4631 [9] Cardoso, F.A.; et al.: Drying behaviour of hydratable alumina-bonded refractory castables. J. of the Europ. Ceram. Soc. 24 (2004) 797–802

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