关键词: 多孔材料, 发泡-自发凝固浇注法, 镁铝尖晶石

Abstract: To improve the thermal efficiency of thermal kilns and reduce the thermal energy loss,porous magnesium-aluminate spinel materials were prepared by the foaming-spontaneous solidification casting method,using industrial-grade medium-grade magnesia fine powder (d₅₀=34.2 μm) and calcined alumina powder (d₅₀=3.4 μm) as raw materials,potassium oleate as a foaming agent,sodium carboxymethyl cellulose as a foam stabilizer,and an alternating copolymer of isobutylene and maleic anhydride (ISOBAM-104,referred to as “IB”) as a curing agent.The effects of the IB extra-addition (0,0.1%,0.2%,0.3%,and 0.4%,by mass) on the properties of the slurry and the specimens after firing at 1 500 ℃ for 3 h were studied.The results show that:(1)with the increase of the IB addition,the expansion ratio of the slurry decreases,and the absolute value of the Zeta potential firstly increases and then decreases;after firing,the apparent porosity of the specimen decreases,the bulk density increases,the cold compressive strength first increases and then decreases,the distribution of pores changes from closely packed to independently dispersed,the pore wall thickens,and the thermal conductivity firstly increases and then decreases;(2)when the IB addition is 0.3%,the Zeta potential is -52.6 mV and the slurry is the most stable;the fired specimen has the maximum cold compressive strength of 32.7 MPa,the apparent porosity of 54.4%,the bulk density of 1.63 g·cm^-3,the thermal conductivity of 0.205 W·m^-1·K^-1 at 350 ℃,and the minimum average pore size of 46.8 μm,the comprehensive properties are the best.

Key words: porous materials, foaming-spontaneous solidification casting method, magnesium-aluminate spinel