关键词: 化学组成, 轻烧尖晶石, 晶体结构参数, 物相组成, 显微结构

Abstract: 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 1 600 ℃. The influence of Al₂O₃ content on the cold physical properties, phase composition, crystal structure parameters and microstructure of samples were investigated. The results show that the increase of Al₂O₃ 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.

Key words: chemical composition, light-burned spinel, crystal structure parameter, phase composition, microstructure