叶蜡石加入量对轻质隔热耐火材料性能的影响

摘要

To solve the problem of over -high density of lightweight insulation refractory bricks prepared with fly ash,new lightweight insulation refractory materials with density <0.89 g·cm -3 were synthesized using pyrophyllite,fly ash,and Suzhou clay as the main starting materials and saw dust as the pore forming sub-stance,and controlling the addition of the pyrophyllite (20%,30%,and 40% by mass)and the treating tem-perature (1 250,1 300,1 350,and 1 400 ℃).The synthesized materials were characterized by the XRD,SEM and the thermal conductivity measuring instrument.The results show at pyrophyllite addition of 30% and treat temperature of 1 400 ℃,the material can achieve linear shrinkage of 6.6%,apparent porosity of 57%,bulk density of 0.75 g·cm -3 ,compressive strength of 2.7 MPa,and thermal conductivity at 350 ℃ of 0.152 -0.216 W·(m·K)-1 .This indicates that the pyrophyllite decomposition at high temperatures forms mullite and amor-phous quartz introducing volume expansion,which counteracts some shrinkage at high temperatures.So it is feasible to use pyrophyllite,fly ash waste and clay to prepare lightweight insulation refractory materials.%为解决以粉煤灰为原料制备轻质隔热砖体积密度过大的问题，利用叶蜡石、粉煤灰、苏州土为主要原料，锯末为造孔剂，通过控制叶蜡石加入量（质量分数分别为20％、30％和40％）和烧成温度（1250、1300、1350和1400℃）合成了体积密度＜0．89 g·cm －3的轻质隔热耐火材料，并利用 XRD、SEM、导热仪等对试样进行表征。结果表明：当叶蜡石加入量为30％（w），烧成温度为1400℃时，制备的隔热砖试样的线收缩率为6．6％，显气孔率为57％，体积密度为0．75 g·cm －3，耐压强度为2．7 MPa，在350℃时热导率为0．152～0．216 W·m －1·K －1。由此说明，通过利用叶蜡石的高温下分解生成莫来石和非晶石英相所产生的体积膨胀效应抵消坯体高温下产生的收缩，结合废弃物粉煤灰以及黏土可制备轻质隔热耐火材料。