Abstract: To improve the service life of MgO-C bricks,based on analyzing the damage mechanism of MgO-C bricks in the slag line of a 210 t refining ladle with a high refining ratio in a steel plant in China,MgO-C bricks were prepared using fused magnesia grade 97,flake graphite,MgO-rich spinel micropowder,antioxidant (Al powder and Si powder),and phenolic resin as raw materials.The effects of the equivalent substitution of MgO-rich spinel micropowder (0,3% and 6%,by mass) for fused magnesia fines on the physical properties,oxidation resistance,and slag resistance of the samples were studied.The results show that compared with the sample without MgO-rich spinel micropowder,the sample with 3% MgO-rich spinel micropowder has significantly improved physical properties,oxidation resistance,and hot modulus of rupture,as well as decreased linear expansion rate;however,as the MgO-rich spinel micropowder addition increases to 6%,the overall performance of the sample shows a downward trend. After applying the MgO-C bricks with 3% MgO-rich spinel micropowder in the ladle slag line under the smelting condition of high refining ratios,the problems such as “steamed bread” melting loss and vertical cracks of MgO-C bricks were significantly relieved.

Key words: magnesia-carbon bricks, magnesia-rich spinel micropowder, physical properties, oxidation resistance, thermal expansion

摘要： 为提高MgO-C砖使用寿命,在分析了国内某钢厂210 t精炼钢包在高精炼比冶炼模式下的渣线MgO-C砖损毁机制的基础上,以97级电熔镁砂、鳞片石墨、富镁尖晶石微粉、抗氧化剂(Al粉+Si粉)和酚醛树脂为原料制备镁碳砖,研究了以不同量(加入质量分数分别为0、3%、6%)的富镁尖晶石微粉等量替代电熔镁砂细粉对试样物理性能、抗氧化性、抗渣性的影响。结果表明:与未添加富镁尖晶石微粉试样相比,添加3%(w)富镁尖晶石微粉时,试样的力学性能、抗氧化性和高温抗折强度都有明显提升,线膨胀率有一定下降;但随着富镁尖晶石微粉加入量增加至6%(w),试样的综合性能呈现下降趋势。将加入3%(w)富镁尖晶石微粉的镁碳砖应用在钢包渣线上,在高精炼比冶炼工况条件下,镁碳砖“馒头状”熔损和竖缝等问题得到明显改善。

关键词: MgO-C砖, 富镁尖晶石微粉, 物理性能, 抗氧化性, 热膨胀性