Abstract: In order to improve the sintering performance of MgO-SiO₂ castables,shorten the sintering time and reduce the production cost,MgO-SiO₂ castables were prepared using fused magnesia,silica micropowder,tabular corundum powder,silicon carbide powder,and magnesite tailings powder as the main raw materials.The effects of the magnesite tailings powder addition (0,2%,4%,6% and 8%,by mass,respectively) on the fluidity,microstructure and mechanical properties of the castables were studied.The results show that:1)the in-situ reaction between highly active MgO generated by the decomposition of magnesite tailings powder and silica micropowder promotes the formation of forsterite neck connection,and the in-situ reaction between magnesia and corundum powder in raw materials promotes the formation of spinel neck connection;2)impurities such as CaO and SiO₂ in magnesite tailings react with MgO at high temperatures to form a low melting point calcium magnesium olivine phase,which exists as a liquid phase at 1 500 ℃,promoting the sintering of the sample;3)when 4% magnesite tailings powder is added,the comprehensive performance of the castable is the best.

Key words: MgO-SiO₂ castables, magnesite tailings, microstructure, mechanical properties

摘要： 为提高MgO-SiO₂质浇注料的烧结性能,缩短烧结时间并降低生产成本,以电熔镁砂、SiO₂微粉、板状刚玉细粉、碳化硅细粉和菱镁矿尾矿细粉为主要原料,制备了MgO-SiO₂质浇注料。研究了菱镁矿尾矿细粉加入量(加入质量分数分别为0、2%、4%、6%和8%)对浇注料流动性、显微结构以及力学性能的影响。结果表明:1)菱镁矿尾矿细粉分解生成的高活性MgO与SiO₂微粉原位反应促进了镁橄榄石颈部连接的形成,且原料中镁砂与刚玉细粉的原位反应促进了尖晶石颈部连接的形成;2)菱镁矿尾矿中的CaO和SiO₂等杂质在高温下与MgO反应生成了低熔点钙镁橄榄石相,在1 500 ℃时以液相存在,促进了试样的烧结;3)添加4%(w)的菱镁矿尾矿细粉时,浇注料的综合性能最佳。

关键词: MgO-SiO₂质浇注料, 菱镁矿尾矿, 显微结构, 力学性能