Abstract: In order to improve the properties of corundum based dispersive purging plugs,dispersive purging plug specimens were prepared using tabular corundum (1-0.15 mm and ≤0.15 mm) as the aggregates,tabular corundum (≤0.044 mm) and α-Al₂O₃ micropowder (d₅₀=0.6 μm) as the matrix,Secar 71 cement as the binder,introducing different amounts of nano-CaCO₃,casting into shapes,and firing at different temperatures (1 200 ℃ or 1 600 ℃) for 4 h.The effects of the nano-CaCO₃ extra-addition (0,0.5%,1%,1.5%,and 2%,by mass) on the fluidity of castables,the properties and the microstructure of the dispersive purging plug specimens were studied.The results show that:(1)with the fixed water addition,the flow value of the corundum castables decreases as the nano-CaCO₃ addition increases;(2)with the increasing nano-CaCO₃ addition,the bulk density of the specimens fired at different temperatures for 4 h decreases,the apparent porosity,the cold strength and the hot modulus of rupture all increase,the air permeability does not change significantly;(3)the specimens fired at 1 600 ℃ for 4 h have obviously better cold physical properties than those fired at 1 200 ℃ for 4 h;(4)when the nano-CaCO₃ addition is 1.5%,the comprehensive performance of the specimen is the optimal.

Key words: dispersive purging plugs, fluidity, nano-calcium carbonate

摘要： 为改善刚玉质弥散型透气砖的性能,以粒度分别为1~0.15、≤0.15 mm的板状刚玉为骨料,以≤0.044 mm的板状刚玉、d₅₀=0.6 μm的α-Al₂O₃微粉为基质,以Secar 71水泥为结合剂,加入不同量的纳米CaCO₃,浇注成型后分别经1 200 ℃保温4 h 、1 600 ℃保温4 h热处理,得到弥散型透气砖试样。研究纳米CaCO₃加入量(外加质量分数分别为0、0.5%、1%、1.5%、2%)对浇注料的流动性、弥散型透气砖性能和显微结构的影响。结果表明:1)在加水量一定的情况下,刚玉质浇注料的流动值随纳米CaCO₃外加量的增加而下降;2)随着纳米CaCO₃外加量的增加,经不同温度保温4 h烧后试样的体积密度下降,显气孔率、常温强度、高温抗折强度均升高,透气性能无明显变化;3)经1 600 ℃保温4 h烧后试样的常温物理性能明显优于经1 200 ℃保温4 h烧后试样的;4)纳米CaCO₃外加量(w)为1.5%时,试样的综合性能较优。

关键词: 弥散型透气砖, 流动性, 纳米CaCO₃