铝土尾矿杂质含量对刚玉-莫来石基复相材料使用性能的影响

以铝土矿尾矿为原料，采用酸浸除杂工艺，通过控制盐酸酸浸过程中的盐酸浓度与液固比，得到不同Fe₂O₃及K₂O含量的精矿，烧结合成了刚玉-莫来石基复相耐火材料。系统研究了不同的二元杂质组成对样条宏观形貌、微观形貌、物相组成、常温力学性能以及高温性能的影响，得到了最佳的盐酸浓度与浸出液固比。结果表明:当尾矿中Fe₂O₃及K₂O含量均<2.0%时，烧结样条的晶相含量及荷重软化温度较高；当杂质Fe₂O₃含量>2.0%且大幅增加时，烧结样条的非晶相含量迅速增加，烧结样条的高温性能下降但常温性能上升，控制烧结样条中的Fe₂O₃及K₂O的含量均<2%时，荷重软化温度保持在1400℃以上，达到市售NZ-45耐火砖的标准。

INFLUENCE OF IMPURITIES IN BAUXITE TAILINGS ON PERFORMANCE OF MULLITE-BASED MULTIPHASE MATERIALS

In this paper, bauxite tailings were used as the raw material, and the acid leaching impurity removal process was adopted, concentrates with different Fe₂O₃ and K₂O contents were obtained by controlling the concentration of hydrochloric acid and the liquid-solid ratio in the process of hydrochloric acid leaching. The influence mechanism of different binary impurity composition on the microscopic morphology, phase composition, normal temperature mechanical properties and high temperature performance of the samples was studied, and the optimal hydrochloric acid concentration and the leaching liquid-solid ratio were obtained. The results showed that when the content of Fe₂O₃ and K₂O in the tailings were both less than 2.0%, the crystalline phase content and load softening temperature of the material were higher; when the content of impurity Fe₂O₃ was greater than 2.0% and greatly increased, the amorphous phase content of the material increased rapidly, performance under high temperature decreased, but performance under room temperature increased. When controlling the content of Fe₂O₃ and K₂O in the bauxite tailings of less than 2%, the load softening temperature was maintained above 1400℃, which met the requirements of the standard for commercially available NZ-45 refractory bricks.