Abstract: This work aims at improving the energy utilization efficiency of kilns.Magnesium aluminate spinel porous insulation materials were prepared as follows.Medium-grade magnesia fine powder and calcined alumina powder were mixed in a mass ratio of 35∶65,dried,and crushed into powders of d₅₀=2.3 μm.Then different amounts of sodium carboxymethyl cellulose (CMC) as a foam stabilizer and 0.6 mass% potassium oleate as a foaming agent were added to obtain the foaming slurry.Finally the slurry was injected into molds of 40 mm×40 mm×40 mm,demolded,dried at 110 ℃ for 24 h,and fired at 1 500 ℃ for 3 h.The effects of the CMC addition (0,0.1%,0.2%,0.3%,0.4%,and 0.5%,by mass,extra adding) on the properties of the slurry and the fired samples were studied.The results show that:(1)when the CMC addition is higher than 0.1%,the slurry has decreased expansion ratio,increased viscosity,and less and smaller bubbles;(2)when the CMC addition is 0.2%,the slurry has the maximum Zeta potential absolute value of 18.3 mV,which is the most stable;the sample has the most pores,which are spherical and closed;the apparent porosity,bulk density,and cold compressive strength of the sample are 73.5%,0.95 g·cm^-3,and 13.1 MPa.

Key words: porous insulation materials, magnesium aluminate spinel, sodium carboxymethyl cellulose

摘要： 为提高热工窑炉的能源利用效率,首先将质量比为35∶65的中档镁砂细粉与煅烧氧化铝粉混合、烘干、破碎至d₅₀=2.3 μm的混合粉;然后分别引入不同量的稳泡剂羧甲基纤维素钠(CMC)和0.6%(w)的发泡剂油酸钾,制得泡沫料浆;最后将泡沫料浆注入40 mm×40 mm×40 mm模具中,脱模,经110 ℃保温24 h干燥,再经1 500 ℃保温3 h烧后,制备了镁铝尖晶石质多孔隔热材料。研究了CMC加入量(外加质量分数分别为0、0.1%、0.2%、0.3%、0.4%、0.5%)对料浆和烧后试样性能的影响。结果表明:1)当CMC加入量大于0.1%(w)后,料浆膨胀比降低,黏度增大,气泡数量减少,气泡平均直径变小。2)当CMC加入量为0.2%(w)时,料浆的Zeta电位绝对值最大,为18.3 mV,此时料浆最稳定;烧后试样内部的气孔为球形封闭气孔,数量最多,此时试样的显气孔率为73.5%,体积密度为0.95 g·cm^-3,常温耐压强度为13.1 MPa。

关键词: 多孔隔热材料, 镁铝尖晶石, 羧甲基纤维素钠