金属铝粉对刚玉尖晶石浇注料抗爆裂性能的影响

Influence of Al Powder on Explosive Spalling Resistance of Alumina-Spinel Castables

以板状刚玉、铝镁尖晶石为主要原料,纯铝酸钙水泥为结合剂,外加不同含量的粒度≤0.15 mm的金属铝粉,制备刚玉尖晶石低水泥浇注料。测定各组试样的抗爆裂温度,并借助于SEM进行了显微结构分析,用压汞法进行孔径分布分析,用压差法进行透气度分析。研究了金属铝粉对刚玉尖晶石浇注料抗爆裂性能的影响,探讨了金属铝粉在浇注料中的造孔机理和防爆作用。结果表明,随着铝粉加入量的增加,刚玉尖晶石浇注料的抗爆裂温度呈现先升高后降低的趋势,这与其透气度的变化趋势一致,说明透气度直接影响了试样的爆裂温度。随着铝粉加入量的增加,浇注料在硬化过程中的放热峰发生稳步前移,但当加入量高于0.075%时,放热峰大幅前移,这样反而不利于排气通道的形成。显微结构分析发现,添加金属铝粉后浇注料的气孔的数目均显著增多,且随着铝粉加入量的增加,气孔孔径也有增大的趋势。

The alumina-spinel refractory castables were prepared using tabular alumina and spinel as main raw materials, calcium aluminate cement as binder, metallic Al powder(≤0.15 mm) as additives. The anti-explosion temperature of castable samples was detected. The characteristics of microstructure, pore size distribution and air permeability were analyzed by SEM, mercury injection apparatus and pressure-difference method, respectively. The influence of Al powder on explosive spalling resistance of alumina-spinel castables were studied, and the pore formation mechanism and explosion-proof of Al powder in castables were investigated. The results show that the anti-explosion temperature of alumina-spinel castables increases and then decreases with the increase of Al powder content, which is consistent with the changing tendency of the air permeability. During the curing of castable samples, the exothermic peak moves forward steadily with the increase of Al content; however, it moves forward significantly when Al powder content exceeds 0.075%. Microstructure analysis shows that the number of pores increases significantly with the Al powder addition, and the pore size of the castables increases with increase of Al powder addition.