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前人研究表明,二次赤铁矿是导致烧结矿低温还原粉化的主要因素,它的生成与烧结原料中MgO含量有关,但其影响机理尚不明确。通过热重法测定不同MgO和Fe_2O_3比例试样在升温-恒温-降温过程中质量变化,定量地了解MgO对Fe_2O_3向Fe_3O_4转变的影响。同时结合XRD分析和光学显微镜观察,揭示了矿物和相结构变化,研究了烧结过程中MgO对二次赤铁矿生成的抑制机理。结果表明,加入MgO后,它与Fe_2O_3反应形成了铁酸镁和含镁磁铁矿,前者促进了升温过程含镁磁铁矿生成,而后者低温下比磁铁矿更稳定,抑制了降温过程磁铁矿氧化,减少了二次赤铁矿的生成。因此,明确了加入少量MgO改善烧结矿低温还原粉化性能的主要原因。
Previous studies have shown that secondary hematite is the main factor leading to the low temperature reduction pulverization of sinter. The formation of secondary hematite is related to the content of MgO in the raw material of sinter, but the influence mechanism is not clear. The change of mass of MgO and Fe_2O_3 samples during heating-thermostatic-cooling process was determined by TG method, and the influence of MgO on the transformation of Fe_2O_3 to Fe_3O_4 was quantitatively studied. At the same time, combined with XRD analysis and optical microscope observation, the changes of mineral and phase structure were revealed, and the inhibition mechanism of MgO on secondary hematite formation was studied. The results show that after adding MgO, it reacts with Fe 2 O 3 to form ferrite and magnetite containing magnetite. The former promotes the formation of magnetite containing magnetite during the heating process, while the latter is more stable than magnetite at low temperature, and inhibits the cooling process Magnetite oxidation, reducing the secondary hematite formation. Therefore, it is clear that the main reason for adding a small amount of MgO to improve the low temperature reduction pulverization properties of sinter.