烧成温度对钙长石隔热耐火材料显微结构与性能的影响

Effect of Sintering Temperature on Microstructure and Properties of Anorthite Insulation Refractory

本工作以矾土水泥与黏土为原料,采用发泡法制备了钙长石隔热耐火材料,通过XRD、SEM和导热仪等分析了烧成温度(1110~1310℃)对钙长石隔热耐火材料显微结构与性能的影响,并研究了该种钙长石隔热耐火材料的合成机理。结果表明:当烧成温度为1110~1160℃时,体系内开始生成钙长石,但原料微颗粒间的反应并不完全,生成的液相含量较少,强度较低;当烧成温度为1210~1260℃时,液相含量增多,钙长石的生成速度加快,强度增大,试样具有较低导热系数;当烧成温度为1310℃时,液相含量迅速增多,线收缩率迅速增大,试样具有较大强度,但体积密度大幅增长,气孔率降低。在1260℃时,制得了体积密度为0.53 g/cm^(3)、气孔率为82.6%、抗折强度为1.15 MPa、耐压强度为1.99 MPa、800℃导热系数为0.101 W/(m·K)的钙长石隔热耐火材料。

In this work,bauxite cement and clay were used as raw materials to prepare anorthite insulation refractory by foaming method.On the basis of analyzing the effect of sintering temperature(1110~1310℃)on the microstructure and properties of anorthite insulation refractory by XRD,SEM and thermal conductivity meter,the synthesis mechanism of anorthite insulation was studied.The results show that when the sintering temperature is between 1110℃and 1160℃,anorthite begins to form,but the reactions between raw materials are not complete,the liquid phase content is less and the strength is lower.When the sintering temperature is between 1210℃and 1260℃,the liquid phase content increases,the rate of anorthite formation was accelerates,the strength increases,and the samples have a low thermal conductivity.When the sintering temperature is 1310℃,the liquid phase content increases rapidly,the linear shrinkage rate increases rapidly,and the samples have higher strength,but the bulk density increases significantly and the porosity decreases.At 1260℃,the anorthite insulation refractory is prepared,with bulk density of 0.53 g/cm^(3),porosity of 82.6%,flexural strength of 1.15 MPa,compressive strength of 1.99 MPa,and thermal conductivity of 0.101 W/(m·K)at 800℃.