材料期刊网

本文研究了碱金属和氟或两者综合,以及它们的不同存在状态对球团矿还原膨胀的影响。在模拟包钢工业球团的碱金属和氟含量的条件下,通过分步还原,发现球团矿的异常还原膨胀主要发生在第一还原阶段,并出现了严重的铁氧化物晶体开裂。只有在含碱金属特高的样品中在第三还原阶段出现严重的铁须。此外还研究了碱金属和氟对球团矿渣相热稳定性的影响.采用x射线衍射及Mossbauer谱分析了碱金属在铁氧化物不同还原阶段的赋存状态及其对它们的晶体结构的影响,借助于TDA对含碱金属铁氧化物的还原进行动力学分析,提出了碱金腻导致铁氧化物晶体开裂及铁须生长的机理模型。

The effect of alkalis, fluorine or combination of both, either in vapour state or in contaminated state on the swelling properties of the pellets during reduction were studied. It was proved that the abnormal swelling of pellets contained alkalis and fluorine during reduction mainly occur in the stage of Fe_2O_3-Fe_3O_4, which was accompanied by abnormal rupture of iron oxide crystal, whereas the pellets contained high K occur obvious swelling in the stage of Fe_xO-Fe which was appeared with serious iron whisker growth. By means of step reduction of oxidized high pure Fe sample permeated with K or Na, it has been proved that the abnormal rupture of the iron oxide crystal and iron whisker growth are resulted from the high alkalis content. On the other hand, the bonding phase contained alkalisfluorine in the pellet became liquid during reduction and lost their bonding force to resist the stress caused by the volume expansion due to rupture of iron oxide crystal or iron whisker growth, thus caused more serious abnormal swelling of the pellets. From the analysis of the reduction sample by X-ray diffraction and Mossbauer spectra and study on the reduction rate at the interface between iron oxides, the causes of crystal rupture and iron whisker growth were clarified, the mechanism mode of the rupture of iron oxide crystal and iron whisker growth has also been proposed.