材料期刊网

为了优化红柱石基耐火材料的生产工艺参数，寻求生产热风炉用优质红柱石砖的最佳工艺路径，研究了红柱石粗颗粒预烧温度对红柱石基耐火材料物理性能的影响，并探讨了影响机制。首先将南非红柱石粗颗粒（4～1 mm）分别在1300、1400、1500、1600℃下预烧3 h，再与红柱石的中颗粒（≤1 mm）和细粉（≤0．088 mm）以及烧结氧化铝粉（≤0．044 mm）和结合黏土进行配料制样后，于1500℃保温3 h 烧成，然后检测试样的体积密度、显气孔率、耐压强度、烧成线变化及1400和1550℃下的压蠕变率（载荷0．2 MPa，保温时间50 h），并采用XRD 分析试样压蠕变试验前后的物相组成。结果表明：经1400℃预烧的红柱石粗颗粒在试样烧成过程中产生的体积收缩减弱了二次莫来石化反应的膨胀效应，可使试样获得较好的物理性能；预烧红柱石粗颗粒保留的未平衡状态在材料高温压蠕变过程中将继续向平衡态发展，期间产生的膨胀效应有效地抵抗了压缩蠕变。可见，在本试验条件下，将红柱石粗颗粒于1400℃左右预烧后使用，可以有效改善红柱石基耐火材料的物理性能。

To optimize the production parameters of andalusite based refractories,the effect of the andalu-site coarse aggregate calcination temperature on properties of andalusite based refractories was re-searched and the mechanism was discussed.In this work,andalusite coarse aggregate (4 -1 mm)was precalcined at 1 300 ℃,1 400 ℃,1 500 ℃ and 1 600 ℃ for 3 h,respectively;then various starting materials including the andalusite medium particles (≤1 mm)and fines (≤0.088 mm)and sintered alumina pow-der (≤0.044 mm)and bonding clay were batched and mixed.The shaped specimens were fired at 1 500℃ for 3 h and then cooled to room temperature.The bulk density,apparent porosity,crushing strength,fir-ing linear change and high temperature creep ratio (1 400,and 1 550 ℃ for 50 h,under a load of 0.2 MPa) of the fired specimens were tested,and the phase composition of the fired specimens before and after creep experiment was investigated by XRD.The results show that the shrinkage originated from andalusite aggregate precalcined at 1 400 ℃ counteracts the expansion of secondary mullitization during sintering, which endows the andalusite based material with better physical properties;the non-equilibrium state in the precalcined andalusite aggregate approaches the equilibrium state during creep experiment;at the same time expansion caused by mullitization counteracts compression creep of specimen effectively.In this ex-periment,the comprehensive physical properties of andalusite based refractories can be improved by using the andalusite aggregate precalcined at around 1 400 ℃.