作者：M. A. L. BRAULIO;D. H. MILANEZ;E. Y. SAKO;L. R. M. BITTENCOURT;V. C. PANDOLFELLI;

作者单位：Federal University of Sao Carlos Materials Engineering Department Materials' Microstructural Engineering Group (GEMM) Km 235, Rod. Washington Luis, 13565-905, Sao Carlos, SP, Brazil;Federal University of Sao Carlos Materials Engineering Department Materia

刊名：Journal of the Technical Association of Refractories

ISSN：0285-0028

出版年：2011-01-05

卷：31

期：1

起页：27

止页：33

分类号：TQ175

语种：英文

关键词：

内容简介

The increasing addition of magnesia to refractory castables is one of the technological challenges of this sort of materials, due to the MgO outstanding basic slag corrosion resistance and relative low costs. Nevertheless, its content in castables is limited by its intense hydration likelihood, which can result in cracks. At high temperatures (>1200°C ), the in situ spinel (MgAl_2O_4) can also lead to further expansion. As calcium aluminate cement is the most common refractory tastable binder, this work addressed the addition of different cement contents (2, 4 or 6 mass%) to high-magnesia containing castables and their effect on the main processing features. The green mechanical strength and the drying rate measurements indicated that cement is an important player in magnesia hydration. Although higher CAC contents resulted in higher splitting tensile strength, the thermogravimetric tests suggested that higher cement additions lead to greater brucite formation. Additionally, the high temperature tests (linear change up to 1500°C) highlighted the cement effect on the shrinkage of this sort of castables. SEM and thermodynamic simulations were also conducted and their proper agreement indicated that these calculations were a suitable tool to understand the sintering mechanism of this sort of castables.