Abstract:

In order to reduce the thermal energy loss of high temperature kilns and furnaces and lower the surface temperature of the kiln body,magnesia insulation materials were prepared using self-made magnesia porous aggregates (using high purity magnesia powder as starting material and potassium oleate as foaming agent),middle grade magnesia powder,calcium aluminate cement,and SiO₂ micropowder as starting materials,introducing walnut shell powder impregnated with silica sol (short for Sws) as a pore-making agent.The effect of the Sws addition (0,10%,15%,and 20%) and the sintering temperature (1 300,1 350,1 400,and 1 480 ℃) on the properties of magnesia insulation materials was studied.The results show that (1)when the Sws addition is 10 mass%,the compressive strength is 22 MPa;when the Sws addition is 20%,the thermal conductivity is 0.368 W·m^-1·K^-1(350 ℃);(2)nano-silica in the silica sol reacts with MgO in the matrix to form forsterite,which encapsulates the pores volatilized from the walnut shell powder and forms closed pores.

Key words: foaming method, ignition loss method, walnut shell powder impregnated with silica sol, magnesia porous aggregates, magnesia insulation materials

摘要：

为了减少高温窑炉的热能损耗,降低窑体的表面温度,以自制的镁质多孔骨料(以高纯镁粉为原料,以油酸钾为发泡剂)、中档镁砂粉、铝酸钙水泥、SiO₂微粉为原料,引入硅溶胶处理后的核桃壳粉(以Sws表示)作为造孔剂,制备镁质隔热材料试样。研究了Sws的加入量(质量分数分别为0、10%、15%和20%)和烧结温度(1 300、1 350、1 400和1 480 ℃)对试样性能的影响。结果表明:1)1 480 ℃时添加Sws为10%(w)时,试样耐压强度为22 MPa;添加Sws为20%(w)时,热导率为0.368 W·m^-1·K^-1 (350 ℃)。2)硅溶胶中的纳米SiO₂与基质内的MgO反应生成镁橄榄石,将核桃壳粉挥发后的气孔包裹起来,形成封闭气孔。

关键词: 发泡法, 烧失法, 硅溶胶浸渍处理核桃壳粉, 镁质多孔骨料, 镁质隔热材料