关键词: 镁碳砖, 电熔镁砂, 物相组成, 显微结构

Abstract:

In order to explore the effect of different fused magnesia particles on their properties,four kinds of magnesia-carbon brick samples were prepared using 97 fused magnesia,97.5 fused magnesia,97.5 fused magnesia (with mole ratio of CaO∶SiO₂ >2) and 97.5 large crystalline fused magnesia as aggregates (all of them with the particle size of 6-3,3-1,1-0.074 and ≤0.074 mm),97.5 large crystalline fused magnesia powder (≤0.074 mm) as the matrix,phenolic resin as the binder and -196 graphite as the carbon source.The bulk density,the apparent porosity,the cold compressive strength,the hot modulus of rupture,the slag resistance,and the oxidation resistance of the samples as well as the phase composition and microstructure were tested according to the national standards.The results show that:(1)the periclase grain size,the hot liquid content and the high melting point phase are the three major factors affecting the properties of the magnesia-carbon brick samples;(2)the larger the grain size of periclase,the better the performance of the samples;(3)the hot liquid content is one of the main factors to reduce the hot performance of the samples;(4)the high melting point phase increases the apparent porosity of the samples,reduces the cold compressive strength and the hot modulus of rupture,and has obvious effects on the oxidation resistance and the slag resistance.

Key words: magnesia-carbon brick, fused magnesia, phase composition, microstructure