刚玉细粉加入量对MgO-MA质耐火材料性能的影响

Effect of corundum fine powder addition on properties of MgO-MA refractories

为提高方镁石-镁铝尖晶石(MgO-MA)质耐火材料的性能,分别以质量分数为0、1.6%、3.2%、4.8%、6.4%、9.6%、12.8%和16%的刚玉细粉替代基质中的镁砂细粉,借助热力学软件Factsage计算了不同刚玉细粉加入量对应的尖晶石理论生成量,通过XRD和SEM对试样的物相组成及微观结构进行分析,研究了刚玉细粉加入量对MgO-MA质耐火材料力学性能、抗热震性能和抗渣性能的影响。结果表明:当刚玉细粉加入量(w)为3.2%时,在渣与试样界面处生成了致密的尖晶石保护层,对试样的抗渣性能有所改善;同时尖晶石生成过程中产生的体积膨胀,在一定程度上改善了试样的抗热震性能。当刚玉细粉加入量超过3.2%(w)时,生成较多的尖晶石,使得试样产生较大的体积膨胀,力学性能开始下降;当加入量超过9.6%(w),经1 600℃热处理后的试样有明显开裂,试样整体性能下降明显。

In order to improve the properties of MgO-MA refractories,magnesia fine powder in the matrix was replaced by corundum fine powder with the mass fraction of 0,1.6%,3.2%,4.8%,6.4%,9.6%,12.8%and 16%,respectively.The theoretical spinel production corresponding to the addition of corundum fine powder was calculated by Factsage,the phase composition and the microstructure of the refractories were analyzed by XRD and SEM,and the effects of the corundum fine powder addition on the mechanical properties,thermal shock resistance and slag resistance of the MgO-MA refractories were studied.The results show that when the addition of corundum fine powder is 3.2%,a dense spinel protective layer is formed at the interface between the slag and the specimen,which improves the slag resistance of the specimen,while the thermal shock resistance is improved by the volume expansion that produced during the spinel formation;when exceeding 3.2%,more spinel is formed leading to larger volume expansion,so that the mechanical properties of the specimen begin to decline;and when exceeding 9.6%,the specimen obviously cracks after heat treatment at 1 600℃for 3 h,and the overall performance of the specimen declines obviously.