The Investigation of Expansion Behavior of Bauxite-based Alumina-magnesia Ramming Mix

摘要

In paper,bauxite-based alumina-magnesia ramming mix was prepared using high quality bauxite as aggregates,bauxite,magnesia as matrix and soluble sodium silicate as binder.The expansion behavior as a function of temperature of ramming mix was investigated by adjusting the ratio of w(MgO)/w(Al2O3).The results showed that,as increasing the ratio of w(MgO)/w(Al2O3),the expansion volume became larger and expansion rate became bigger in the temperature range of 950～1450°C due to in situ spinel formation.In temperature range of 1300～1500°C,vast molten phase appeared because of the presence of silica and impurities of TiO2 and Fe2O3 introduced from bauxite,gradually counterbalancing the expansion associated to the in situ spinel.While at 1600°C,plastic reaction begun due to the presence of mass molten phase and the impurities of TiO2 and Fe2O3 dissolved in the in situ spinel,causing lattice deformation and leading to expansion against that at 1500°C.