Incorporating Nano-silica as a Binder to Improve Corrosion Resistance of High Alumina Refractory Castables

• Published in: Journal of materials engineering and performance 2013-04, Vol.22 (4), p.1010-1017
• Main Authors: Ramezani, Abbas, Mohebi, Mohammad Masoud, Souri, Alireza
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Characterization and Evaluation of Materials; Chemical industry and chemicals; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Exact sciences and technology; General studies; Materials Science; Quality Control; Reliability; Safety and Risk; Technical ceramics; Tribology
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-012-0389-7

In this study, four types of castables as calcium-aluminate cement (CAC)-bonded and nano-silica (NS)-bonded castables based on tabular-alumina and bauxite aggregates were prepared to investigate the replacement of the calcium-aluminate cement by NS. All samples were allowed to dry at 110 °C then fired at 800 and 1200 °C. Bulk density and apparent porosity of samples were measured. The molten aluminum static corrosion test (cup test) results showed that NS-bonded specimens had higher resistance to corrosion compared to CAC-bonded samples (based on the measured average aluminum penetration depth into the refractory texture). However no penetration was observed in bauxite NS-bonded samples. The results were consistent with dynamic corrosion test in aluminum melt carried out at 800 °C for 100 h. The small pore size in NS-bonded castables was found to be the main cause for high corrosion resistance as micro-pores prevented the melt to penetrate into the refractory.