白云石微粉对刚玉-尖晶石质浇注料物理性能的影响

Effect of ultra-fine dolomite on physical property of corundum-spinel castables

以电熔白刚玉、电熔镁铝尖晶石、氧化铝微粉、白云石微粉以及铝酸钙水泥为主要原料,研究了白云石微粉加入量(质量分数分别为0、1.5%和3%)对刚玉-尖晶石质浇注料物理性能的影响。结果表明:加入1.5%白云石微粉对浇注料的线变化率影响不大,并能够明显提高浇注料800～1100℃烧后的冷、热态抗折强度,对1400℃烧后的冷、热态抗折强度影响不大,但1600℃烧后冷、热态抗折强度降低。加入3.0%的白云石微粉使各试验温度烧后浇注料的线变化率增大且不利于浇注料强度的提高。与1400℃烧后相比,1600℃烧后所有试样冷、热态强度均有所降低,而且随白云石微粉加入量的增加降低幅度增大。白云石微粉的加入能够明显提高刚玉-尖晶石质浇注料的强度保持率,但试样热震前后的抗折强度均明显降低。

Using white fused alumina,fused magnesia -alumina spinel, ultra-fine alumina,ultra-fine dolomite and calcium aluminate cement as starting materials,the effect of ultra-fine dolomite additions （0,1.5% and 3% ） on physical properties of corundum -spinel castables was investigated. The results show that： （1）The permanent linear change rate of the castables with 1.5% ultra-fine dolomite is very close with that of castables without dolomite. Adding 1.5% ultra-fine dolomite,the cold and hot modulus of rupture of the castables fired at 800 ～ 1 100 ℃ are significantly improved,those at 1 400 ℃ has no change, but those at 1 600 ℃ is decreased;（2）Adding 3.0% ultra-fine dolomite leads to the increase of linear change rate of the castables after firing at all test temperatures and has negative effects on the strength of the castables; （3） Compared with the specimens fired at 1 400 ℃,the cold and hot modulus of rupture of the castables fired at 1 600 ℃ are lower, and the higher of ultra-fine dolomite addition, the lower of the modulus of rupture;（4）The residual strength ratio of the corundum -spinel castables with ultra-fine dolomite addition obviously increases, but their strength values before and after thermal shock tests decrease.