Microporous Design And Property Of Lightweight Insulation Refractory Materials Prepared From Calcined Flint Clay

Most of lightweight insulation materials were prepared by using clay as main materials,which increased shrinkage.Calcined flint clay which was used as excellent refractory material had good volume stability and low water absorption.Therefore,calcined flint clay was used to prepare mullite lightweight insulation refractory material.In this paper,micropores and properties were investigated by using calcined flint clay to prepare lightweight insulation refractory materials.The main contents in this paper include two parts:(1)Effects of temperature and contents of calcined flint clay on the microstructures and properties of mullite lightweight insulation refractory materials were studied.(2)Influences of kinds of sol and alumina sol concentrations on the microporosity of lightweight insulation refractory materials were researched.The results were shown as follows:(1)Lightweight insulation refractory materials were prepared from calcined flint clay,with the comprehensive properties.As the content of calcined flint clay was 40 wt%,the temperature was 1400 ?,bulk density,cold crushing strength and apparent porosity were 0.89 g/cm3,and 2.65 MPa,71%,respectively.Thermal conductivities of materials were 0.133 W/(m?K),0.188 W/(m?K)and 0.232 W/(m?K)at 300 ?,600 ? and 900 ?,respectively.Linear change reheating rate was +0.18% at 1400 oC for 24 h.(2)When sawdust was used as pore forming-agent,effect of pore size distribution on thermal conductivity and cold crushing strength was concentrated in 2-6 ?m and 26-30 ?m.While sawdust was soaked by using alumina sol,influence of pore size distribution on thermal conductivity and cold crushing strength was concentrated in 2-8 ?m and 18-22 ?m.(3)Lightweight insulation refractory materials with sawdust infused by using alumina sol,which had the better comprehensive.As the concentration of alumina sol was 7wt%,the temperature was 1400 ?,cold crushing strength,bulk density and Apparent porosity were 3.5 MPa,0.98 g/cm3 and 68%,respectively.Thermal conductivities were 0.124 W/(m?K),0.167 W/(m?K)and 0.201 W/(m?K)at 300 ?,600 ? and 900 ?,respectively.