Abstract: Aiming at the regulation and optimization of microstructure and mechanical properties of Al₂O₃-ZrO₂-C refractories green bodies,Al₂O₃-ZrO₂-C refractory samples and their matrix samples were prepared by mechanical compression molding with the tabular corundum,zircon mullite and zircon corundum as aggregates,the α-Al₂O₃ micropowder,flake graphite and additives as fine powders,and the lignosulfonate as the binder.Influences of different fine powder mixing processes (0.5 h manual mixing,no mixing,2 h ball milling,and 5 h ball milling) on the bulk density,apparent porosity,cold compressive strength,and microstructure were investigated.The results indicate that the fine powder mixing process has minimal impact on the apparent porosity and bulk density,but it significantly affects the microstructure and cold compression strength.Ball milling ensures an even distribution of raw materials while reducing defects such as pores and cracks;it also enhances particle size uniformity and the specific surface area of matrix raw materials,which facilitates the adsorption and bonding with lignosulfonate solution,thereby obviously improving the strength.However,excessive ball milling may result in excessively fine particles or increased agglomeration,reducing the strength.When the fine powder is mixed by ball milling for 2 h,an optimal combination between the matrix components and the aggregates is achieved,resulting in the highest cold compressive strength.

Key words: Al₂O₃-ZrO₂-C refractories, mixing process, cold compressive strength, microstructure

摘要： 针对铝锆碳耐火材料生坯显微结构和力学性能的调控与优化,以板状刚玉、锆莫来石、锆刚玉为骨料,α-Al₂O₃微粉、鳞片石墨、添加剂为细粉,木质素磺酸盐为结合剂,机压成型制备铝锆碳耐火材料试样和基质试样。研究了细粉的混料工艺(手动混料0.5 h、未混料、球磨混料2和5 h)对基质试样和耐火材料试样体积密度、显气孔率、常温耐压强度和显微结构的影响。结果表明:细粉的混料工艺对试样显气孔率和体积密度的影响较小,但对显微结构和常温耐压强度影响显著。球磨混合使得原料分布均匀,显著减少气孔、裂纹等缺陷,并使得基质原料的粒度均匀性提高和比表面积增加,有利于木质素磺酸盐溶液结合剂的吸附和黏结,从而保证强度的明显提升。但过长的球磨时间可能会导致原料颗粒过细,团聚增多,反而降低了强度。当细粉经2 h球磨混合时,试样中基质与骨料结合较为紧密,常温耐压强度最高。

关键词: 铝锆碳耐火材料, 混料工艺, 常温耐压强度, 显微结构