在采用多孔介质模型进行微孔骨料孔径数值模拟设计的基础上,分别以α-Al2O3微粉、工业Al2O3细粉、α—Al2O3微粉+CaCO3细粉为原料,通过湿磨工艺分别制备了三种微孔刚玉骨料A1、A2、A3,并分别以平均孔径约O.6μm的Al和A3两种微孔刚玉为骨料制成轻质铝镁浇注料,与采用板状刚玉骨料制备的普通铝镁浇注料进行了性能对比。结果表明:1)以α-Al2O3微粉、工业Al2O3细粉等为主要原料,在1800℃以上烧结可获得体积密度为3.1~3.5g·cm^-1、显气孔率约5%、闭口气孔率为8%~13%的微孔刚玉骨料,其800℃的热导率比板状刚玉的小;2)与普通铝镁浇注料相比,两种轻质铝镁浇注料的显气孔率较大,体积密度较小,1500℃处理后的强度较高,线变化率较小,在600和800℃时的热导率明显较小;3)与普通铝镁浇注料相比,含A1骨料的铝镁浇注料渗透指数偏大,含A3骨料的铝镁浇注料的侵蚀指数稍大,但渗透指数小。
Based on the pore size design of micro-porous aggregate by numerical simulation applying porous media model, α-Al2O3 micropowder, industrial Al2O3 fine powder, α-Al2O3 micropowder + CaCO3 fine powder were used as starting materials,respectively,the three micro-porous corundum aggregates named as A1 ,A2 and A3 were prepared by wet grinding process,and two lightweight Al2O3-MgO castables were prepared by selecting A1 or A3 with 0.6μm of average pore size as aggregate, then performances of castables with micro-porous corundum aggregates and castables with tabular corundum aggregates were compared. The results show that:( 1 ) the micro-porous corundum aggregates with bulk density of 3.1-3.5 g · cm-3 ,apparent porosity of 5% ,closed porosity of 8%-13% ,and smaller thermal conductivity at 800℃ than tabular corundum,can be prepared by firing above 1 800 ℃; (2)compared with normal Al2O3-MgO castables,the two lightweight Al2O3-MgO castables have lower bulk density and higher apparent porosity; lower change rate in dimensions and higher strength firing at :1 500 ℃;and lower thermal conductivity at 600 and 800℃; (3)compared with normal Al2O3-MgO castables,Al2O3-MgO castable with aggregate A1 has higher penetration index,and that with aggregate A3 has higher corrosion index and lower penetration index.