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对一种细粒度磁铁精矿粉制备的生球团,通过调整其预热及焙烧工艺参数,生产出不同抗压强度的球团矿,并对其孔隙率以及还原度和还原膨胀率进行了测定。试验结果表明,随着球团矿抗压强度的提高,其孔隙率呈下降趋势,其900℃还原度也呈下降趋势,而还原膨胀率变化不大。对不同抗压强度球团矿的矿相进行了测定,结果表明,预热时间的延长,使球团初期的预热氧化过程更加完全,Fe2O3微晶键更好地发育和长大,而焙烧温度的升高,则可以促进后期Fe2O3的再结晶和长大,提高晶键互连程度,晶粒紧密连接成片,孔隙率下降,使焙烧球团具有较高的抗压强度,但结构致密,变得难以还原。
For a pellet prepared from fine-grained magnetite concentrate, the pellets with different compressive strength were produced by adjusting the preheating and calcination process parameters, and the porosity, reduction degree and reduction expansion rate Determination. The experimental results show that with the increase of the compressive strength of pellets, the porosity of the pellets shows a downward trend, and the reduction of 900 ℃ also shows a downward trend, while the reduction and expansion rate does not change much. The mineral phase of pellets with different compressive strength was measured. The results showed that the preheating time was extended to make the pellet preheating and oxidation process more complete, the Fe2O3 crystallite bond was better developed and grown, and the roasting The increase of temperature can promote the recrystallization and growth of Fe2O3 in the late stage, improve the degree of crystal-crystal interconnection, the crystal grains are closely connected into pieces and the porosity decreases, so the roasting pellets have higher compressive strength, but the structure is compact , It becomes difficult to restore.