亚白刚玉对红柱石细粉烧结性能的影响

摘要

South Africa andalusite powder and sub-white corundum powder were used as starting materials to research the effect of sub-white corundum additions (5%,10%,15%,20%,25%,30% and 35%,by mass)on mullitization and sintering behavior of andalusite powder fired at different temperatures (1 150, 1 200,1 250,1 300,1 350,1 400,1 450,1 500 and 1 600 ℃).It is shown that after sub-white corundum is intro-duced into andalusite powder system,the sintering behavior of the system is controlled by the compositive effect originating from expansion effect caused by primary mullitization and secondary mullitization and promoting sintering effect caused by high temperature liquid phase.Below 1 350 ℃ there is mainly primary mullitization in the system by which the sintering behavior is influenced,and the addition of sub-white co-rundum has little effect.Above 1 400 ℃,secondary mullitization occurs and dominates the sintering behav-ior.The extent of secondary mullitization increases with the addition of sub-white corundum increasing and accordingly the sintering performance of andalusite powder is deteriorated.Therefore,when sub-white co-rundum is used as additive to increase mullite amount in the andalusite based refractories and thus im-prove their high temperature properties,the optimal addition and firing temperature should be properly de-termined according to the performance requirements of the finished products.%为了考察亚白刚玉对红柱石基耐火材料烧结性能的影响，以南非红柱石细粉和亚白刚玉细粉为原料，研究了亚白刚玉加入量（加入质量分数分别为5％、10％、15％、20％、25％、30％和35％）对红柱石细粉在不同温度（1150、1200、1250、1300、1350、1400、1450、1500和1600℃）煅烧后莫来石化和烧结性能的影响。结果表明，引入亚白刚玉后，红柱石细粉的烧结性能受控于原生莫来石化反应和二次莫来石化反应的膨胀效应，以及高温液相促进烧结的综合作用。低于1350℃时，系统中发生的主要是原生莫来石化反应，系统的烧结行为主要受原生莫来石化反应的膨胀效应影响，亚白刚玉加入量对红柱石细粉的烧结性能影响不大。高于1400℃时，系统中将产生二次莫来石化反应并主导系统的烧结行为，二次莫来石化反应的程度随着亚白刚玉加入量的增加而增大，红柱石细粉的烧结性能也随之恶化。可见，以亚白刚玉作为添加剂来提高红柱石基耐火材料的莫来石含量，进而改善其高温性能时，应该根据制品的性能指标要求，合理确定最佳亚白刚玉加入量和煅烧温度。