镁铝尖晶石质耐火材料的合成

Synthesis of magnesia-alumina spinel refractories

以MgA l2O4为骨料,MgO和A l2O3为基质料,通过固相烧结法合成了镁铝尖晶石质耐火材料,考察了原料组成、骨料粒度和成型压力对一步烧结法合成镁铝尖晶石烧结性能的影响.结果表明,随着基质料含量的增加和骨料粒度的增大,试样的线变化率和显气孔率逐渐增大;随着成型压力的增加,试样的显气孔率明显减小,线变化率增加.以镁铝尖晶石(粒度<177μm)为骨料,按镁铝尖晶石,氧化镁,氧化铝的摩尔比为20∶40∶40配料,在200 MPa压力下成型,可以获得显气孔率较低、线变化率适宜的镁铝尖晶石质耐火材料.

Magnesia-alumina spinel refractories were synthesized by solid-state sintering with MgAl2O4 as aggregate, MgO and Al2O3 as matrix materials. The effects of composition of the starting materials, aggregate size and forming pressure on the sinterability of the samples were studied. The results showed that the linear expansivity and apparent porosity of the samples irtcreased with increasing the percentage of matrix materials and aggregate size. The apparent porosity of the samples was significantly decreased and the linear expansivity increased with increasing the forming pressure. When the aggregate size was smaller than 177 μm, with the composition （mole ratio） of magnesia-alumina spinel/magnesia/alumina of 20/40/40 and the forming pressure of 200 MPa, sintered spinel refractories with low apparent porosity and proper linear expansivity were obtained.