The performance of the blast furnace is strongly affected by the position and thickness of the cohesive zone, which is largely influenced by the high-temperature properties of the iron-bearing materials. During its reduction, softening and melting, ferrous materials undergo major microstructure changes and its understanding is essential to develop new raw-materials, technologies, and models. In this study, the behavior of reduction, softening and melting of a lump ore, an acid pellet, and a sinter was characterized by softening and melting (S&M) experiments. After that, to access the samples’ structural transformations, interrupted S&M tests were carried out up to four different conditions based on contraction and pressure loss levels. The obtained products were characterized according to its density (true and apparent), porosity (open, closed and total), phase composition by X-ray diffraction and microstructure (reflected light microscopy and electron scanning microscopy). From the S&M test results, three main regions of reduction were characterized, namely: solid/gas reduction, reduction retardation, and melting reduction. In the solid/gas reduction, samples open porosity increased, with reduction following the shrinking core model. On the region of reduction retardation, a sharp decrease in open porosity was identified together with the diminishing of the reduction rate, which occurred due to the iron shell porosity being clogged due to the slag transfer from the particles’ cores to its periphery. At the melting exudation region, reduction retardation ceased and exudation of the ferrous slag lead to a peak of reduction. The lower the reduction degree of the samples at this stage, the higher the consumption of carbon. Furthermore, at 10 pct contraction, a pseudo-globular wüstite structure interspersed with slag was observed for the pellet and sinter cores. At 50 pct contraction, the previous structure coalesced to form a globular shape wüstite in a well-connected slag matrix.

高炉的性能受粘结区的位置和厚度的强烈影响，而粘结区的位置和厚度在很大程度上受含铁材料的高温性能影响。在还原，软化和熔化过程中，黑色金属材料会发生重大的微观结构变化，对黑色金属的理解对于开发新的原材料，技术和模型至关重要。在这项研究中，通过软化和熔融（S＆M）实验来表征块矿，酸性颗粒和烧结矿的还原，软化和熔融行为。此后，为了获得样品的结构转变，根据收缩和压力损失水平，在多达四个不同的条件下进行了中断的S＆M测试。根据其密度（真实和表观），孔隙率（开孔，X射线衍射和显微结构（反射光显微镜和电子扫描显微镜）的相组成。从S＆M测试结果中，可以确定还原的三个主要区域，即：固体/气体还原，还原延迟和熔融还原。在固/气还原过程中，样品的开孔孔隙度增加，并且随着收缩岩心模型的减少而减小。在还原阻滞区域，发现开孔孔隙率急剧下降，同时还原速率降低，这是由于铁壳孔隙率由于炉渣从颗粒核心转移到其外围而被堵塞所致。在熔融渗出区，还原延迟停止，铁渣的渗出导致还原峰。在此阶段，样品的还原度越低，碳的消耗量就越高。此外，在收缩10 pct时，对于粒料和烧结芯，观察到散布有炉渣的伪球形wstite结构。在收缩50 pct时，先前的结构会聚结在一起，在连接良好的炉渣基质中形成球形的wstite。