Thermal characteristics of Al2O3-MgO and Al2O3-spinel castables for steel ladles

• Published in: Ceramics international Vol. 28; no. 7; pp. 811 - 817
• Main Authors: CHEN, Swe-Kai, CHENG, Min-Yuan, LIN, Su-Jien, KO, Yung-Chao
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Science 2002
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Exact sciences and technology; Gravity die casting and continuous casting; Iron and steel making; Metals. Metallurgy; Production of metals; Refractory products; Silica-alumina refractories; Deformation; Chemical resistance; Rupture modulus; Mechanical properties; Thermomechanical properties; Unshaped refractory; Experimental study; Castable refractory; Thermal properties; Spinel refractory; Pore size; Ladle; Thermal shock resistance; Magnesia; Steelmaking; Slag; Microstructure; Basic refractory; Alumina
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/S0272-8842(02)00047-0

The hot properties of Al2O3-MgO castables containing 5.5 wt% MgO and 1.36 wt% CaO with and without the addition of 0.75 wt% microsilica and Al2O3-spinel castables containing 20 wt% Al2O3-rich spinel of 90 wt% Al2O3 and 1.70 wt% CaO, respectively, were investigated. A thermal shock damage test indicated that the retained modulus of rupture of the Al2O3-MgO castables after three cycles was down to 5%, while that of the Al2O3-spinel castables was 51%. The combined test of slag and thermal shock attack on castables using a rotary slag test furnace showed that Al2O3-MgO castables had 0% penetration and 24% erosion, while Al2O3-spinel castables had 10% penetration and 30% erosion. Field trials confirmed that Al2O3-MgO castables have better slag resistance and a longer service life when used in steel ladles, compared to Al2O3-spinel castables. Based on the lab and field tests the importance of thermal shock damage resistance of castables for use in steel ladles should be de-emphasised. There is no correlation between hot strengths and slag resistance of castables. The magnitude of specific surface area of pores is more important than pore size and porosity for governing the slag resistance of Al2O3-MgO castables, with and without microsilica addition. 12 refs.