化学组成对轻烧镁铝尖晶石结构与性能的影响

Influence of Chemical Composition on Structure and Properties of Light-Burned Magnesium-Aluminum Spinel

相比传统电熔镁铝尖晶石和烧结镁铝尖晶石,轻烧镁铝尖晶石晶格畸变大,反应活性高,所制备的铝镁浇注料抗渣渗透性更好。本文以工业氧化铝和轻烧镁砂细粉为原料,在1600℃下烧结合成Al 2O 3质量分数在68%~76%的富镁尖晶石(68%和70%)、正尖晶石(72%)和富铝尖晶石(76%)试样,研究Al 2O 3含量对尖晶石试样常温物理性能、物相组成、晶体结构参数和显微结构的影响。结果表明:Al 2O 3含量的增加提高了试样的显气孔率;富镁尖晶石试样的物相为尖晶石和少量方镁石,其余试样只有尖晶石相;富铝尖晶石的晶格畸变大于富镁尖晶石和正尖晶石,晶粒尺寸和平均孔径小于富镁尖晶石和正尖晶石。

The aluminum-magnesium castable prepared by the light-burned spinel has better slag penetration resistance due to the larger lattice distortion and higher reaction activity of the light-burned spinel compared with the traditional sintered spinel or fused spinel.The industrial alumina and light-burned magnesia powder were used as raw materials to prepare magnesium-rich spinel(the mass fractions of alumina were 68%and 70%),stoichiometric spinel(the mass fraction of alumina was 72%)and aluminum-rich spinel(the mass fraction of alumina was 76%)after sintered at 1600℃.The influence of Al 2O 3 content on the cold physical properties,phase composition,crystal structure parameters and microstructure of samples were investigated.The results show that the increase of Al 2O 3 content increases the apparent porosities and decreases the linear shrinkage of samples,indicating that the sintering properties of magnesium-rich spinel and stoichiometric spinel are better than that of aluminium-rich spinel.Under the experimental conditions,the solid solution of magnesium oxide into spinel is less than 2%(mass fraction),and the solid solution of alumina into spinel is more than 4%(mass fraction).The phase of magnesium-rich spinel sample is spinel and a small amount of periclase,the other samples only have spinel phase.The solid solution of alumina into spinel makes the lattice distortion of aluminum-rich spinel greater than that of magnesium-rich spinel and stoichiometric spinel,and the grain size and average pore size of aluminum-rich spinel are smaller than that of magnesium-rich spinel and stoichiometric spinel due to the delay of solid solution sintering.