Abstract: Light burned magnesia powder (≤0.074 mm) was prepared with Xiuyan grade Ⅱ magnesite firing at 900 ℃ for 3 h.Samples were prepared by the obtained powder and desiliconized zirconia with different additions (0,4%,8%,12% and 16%,by mass),grinding,mixing,forming,drying,and calcining at 1 500,1 600 and 1 700 ℃ for 3 h,respectively.The bulk density,the relative density,the cold compressive strength and the thermal shock resistance of the fired samples were tested.The phase composition and the microstructure were analyzed.The results show that the cold compressive strength,the relative density and the thermal shock resistance of the samples basically increase first and then decrease with the increase of the desiliconized zirconia addition,achieving the maximum with 8% desiliconized zirconia.The sample added with 8% desiliconized zirconia and sintered at 1 700 ℃ for 3 h has the relative density of 86.21%,the cold compressive strength of 201 MPa and the thermal shock resistance of 6 cycles.

Key words: zirconia, magnesite, magnesia refractories, sintering properties, thermal shock resistance

摘要： 将岫岩二级菱镁矿在900 ℃保温3 h制成≤0.074 mm的轻烧氧化镁粉,再加入不同量(质量分数分别为0、4%、8%、12%、16%)的脱硅锆,经研磨混合、成型、烘干后,分别在1 500、1 600、1 700 ℃保温3 h煅烧,检测烧后试样的体积密度、相对密度、常温耐压强度、抗热震性,并分析试样的物相组成和显微结构。结果表明:随着脱硅锆添加量的增加,烧后试样的相对密度、常温耐压强度和抗热震性基本上都呈先增大后减小的变化趋势,在添加8%(w)脱硅锆时达到最大;添加8%(w)的脱硅锆,在1 700 ℃保温3 h烧结,所得材料的相对密度达到86.21%,常温耐压强度为201 MPa,抗热震性达到6次。

关键词: 氧化锆, 菱镁矿, 镁质耐火材料, 烧结性能, 抗热震性