以硅溶胶浸渍处理核桃壳粉为造孔剂制备镁质隔热材料

Preparation of magnesia insulation materials by walnut shell powder impregnated with silica sol

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、SiO_(2)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(1300、1350、1400和1480℃)对试样性能的影响。结果表明:1)1480℃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SiO_(2)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。

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 SiO_(2) 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(1300,1350,1400,and 1480℃)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.