Abstract: To improve the utilization of low silica fused magnesia waste,magnesia based castables were prepared using fused magnesia,sintered magnesia and low silica fused magnesia waste as main raw materials,replacing sintered magnesia by low silica fused magnesia waste of equivalent particle size (≤75 μm).The effects of the substitution amounts of low silica fused magnesia waste (0,5%,10% and 15%,by mass) on the physical properties and thermal shock resistance of magnesia based castables were investigated.In combination of the microstructure and phase composition,their influence mechanism on the castable properties was analyzed.The results show that:(1)after the heat treatment at 1 550 ℃,with the increasing substitution of low silica fused magnesia waste,the linear shrinkage rate of the castables decreases gradually,the bulk density increases significantly,the apparent porosity shows an obvious downward trend,and the cold compressive strength and strength retention ratio after thermal shock test both increase first and then decrease;(2)when the substitution of low-silica fused magnesia waste is 10%,the magnesia based castables exhibit the optimal comprehensive properties.

Key words: low-silica fused magnesia waste, magnesia-based castables, physical properties, thermal shock resistance

摘要： 为提高电熔氧化镁低硅废料的利用率,以电熔镁砂、烧结镁砂、电熔氧化镁低硅废料为主要原料,用同等粒度的电熔氧化镁低硅废料(≤75 μm)替代烧结镁砂制备了镁质浇注料。研究了不同电熔氧化镁低硅废料替代量(替代的质量分数分别为0、5%、10%、15%)对镁质浇注料物理性能及抗热震性能的影响,并结合显微结构和物相组成变化,分析了电熔氧化镁低硅废料替代量对浇注料性能的影响机制。结果表明:1)经1 550 ℃热处理后,随着电熔氧化镁低硅废料替代量的增加,浇注料的线收缩率逐渐降低,体积密度显著提高,同时显气孔率呈现明显下降趋势,常温耐压强度和热震试验后的抗折强度保持率呈现先升高后降低的变化趋势。2)电熔氧化镁低硅废料替代量为10%(w)时,镁质浇注料表现出较佳的综合性能。

关键词: 电熔氧化镁低硅废料, 镁质浇注料, 物理性能, 抗热震性