连铸复合式水口内层用镁铝尖晶石质耐火材料的合成研究

Study on Synthesis of Magnesia-alumina Spinel Refractory for Inner-lining of the Submerged Nozzle for Continuous Casting

以镁铝尖晶石为骨料、等摩尔的氧化镁粉和氧化铝微粉为基质料,通过一步固相烧结法合成了水口内层用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煅烧法制备镁铝尖晶石烧结性能的影响。研究结果表明,随着骨料粒度增大和基质料含量的增加,试样的烧结性变差,烧成试样的烧后线收缩率变小,显气孔率逐渐增大;随着成型压力的增加,烧成试样的显气孔率和烧后线收缩都明显减小。以80目尖晶石为骨料,按尖晶石∶氧化镁粉∶氧化铝微粉=20∶40∶40配比(mol%),并以200MPa的压力成型,可以获得结构致密、烧后线收缩率适中的尖晶石质水口内层材料。

Magnesia-alumina spinel was used as aggregate, magnesia and alumina powder were used as matrix materials, for the synthesis of magnesia-alumina spinel base inner-lining of submerged nozzle (SEN) by solid-state sintering. The effect of composition of starting materials, aggregate size and molding pressure on the sinterability and the properties of samples were studied. The results showed that the sin- terability of samples became poor, the linear shrinkage decreased and the apparent porosity increased with increasing aggregate size and the percentage of matrix materials; The apparent porosity and the linear shrinkage of samples were effectively decreased with increasing molding pressure. When aggregate size is 80 mesh, with the composition of spinel: magnesia: alumina=20: 40: 40 and molding pressure of 200 MPa, the sintered spinel refractory with dense structure and proper linear shrinkage was obtained.