Effects of pre-synthesized magnesia-zirconia sand and calcination temperature on properties of magnesia-zirconia materials

doi:10.3969/j.issn.1001-1935.2024.02.004

Abstract

Abstract: To improve the hot properties of magnesia-zirconia materials,magnesia-zirconia sand was pre-synthesized with Xiuyan second grade magnesite and desilicated zirconia,and then magnesia-zirconia materials were prepared using the pre-synthesized magnesia-zirconia sand and fused magnesia,mixing,molding,drying and calcining.The effects of the pre-synthesized magnesia-zirconia sand addition (10%,20% and 30%,by mass) and calcination temperature (1 500,1 600 and 1 700 ℃) on the bulk density,apparent porosity,linear shrinkage rate on heating,cold modulus of rupture,thermal shock resistance and slag resistance of the materials were investigated.The phase composition and microstructure were also analyzed.The results show as follows:(1)as the pre-synthesized magnesia-zirconia sand addition and calcination temperature increase,the bulk density and cold modulus of rupture increase,while the apparent porosity decreases;(2)the linear shrinkage rate decreases with the increasing pre-synthesized magnesia-zirconia sand addition and increases with the increasing calcination temperature;(3)when the pre-synthesized magnesia-zirconia sand addition is 20% and the calcination temperature is 1 600 ℃,the sample performs the best thermal shock resistance,which is improved due to microcrack toughening induced by the pre-synthesized magnesia-zirconia sand;(4)when the pre-synthesized magnesia-zirconia sand addition is 20% and the calcination temperature is 1 700 ℃,the sample shows the optimal slag resistance,which is mainly due to the fact that ZrO₂ reacts with the slag to generate CaZrO₃ and spinel,preventing the further corrosion and penetration of the steel slag.

Key words: pre-synthesized magnesia-zirconia sand, calcium zirconate, desilicated zirconia, thermal shock resistance, slag resistance

摘要： 为了改善镁锆质材料的高温使用性能,以岫岩二级菱镁矿、脱硅锆为原料制备的预合成镁锆砂和电熔镁砂为原料,经混合、成型、烘干、煅烧制备了镁锆质材料。研究了预合成镁锆砂加入量(质量分数分别为10%、20%、30%)和煅烧温度(1 500、1 600、1 700 ℃)对镁锆质材料体积密度、显气孔率、烧后线收缩率、常温抗折强度、抗热震性、抗渣性的影响,并分析了其物相组成和显微结构。结果表明:1)随着预合成镁锆砂加入量和煅烧温度的提高,试样体积密度和常温抗折强度增大,显气孔率减小;2)试样线收缩率随预合成镁锆砂加入量的增加而减小,随煅烧温度的升高而增大;3)当预合成镁锆砂加入量为20%(w),煅烧温度为1 600 ℃时,试样的抗热震性最优,这是由于预合成镁锆砂引起的微裂纹增韧提高了抗热震性;4)当预合成镁锆砂加入量为 20%(w),煅烧温度为1 700 ℃时,试样的抗渣性最优,主要原因在于ZrO₂与渣反应生成CaZrO₃和尖晶石,阻碍了钢渣的进一步侵蚀与渗透。

关键词: 预合成镁锆砂, CaZrO₃, 脱硅锆, 抗热震性, 抗渣性

CLC Number:

TQ175

Liu Zhongfei, Feng Yu, Liang Xiaocheng, Luo Xudong, Li Guangwei, Wu Feng. Effects of pre-synthesized magnesia-zirconia sand and calcination temperature on properties of magnesia-zirconia materials[J]. Refractories, 2024, 58(2): 110-115.

刘中飞, 冯雨, 梁效诚, 罗旭东, 李广伟, 吴锋. 预合成镁锆砂和煅烧温度对镁锆质材料性能的影响[J]. 耐火材料, 2024, 58(2): 110-115.

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