高炉软熔带内浮氏体还原-成渣反应非稳态竞争行为的机理研究

The cohesive zone of blast furnace has a great influence on the smooth operation and fuel consumption, for it determines the gas flow distribution and utilization. It is of great importance to obtain the reasonable structure of the cohesive zone for blast furnace operation by studying its formation mechanism. The previous work is centered on the evaluation of the shape and permeability of the cohesive zone by measuring the physical indices of the softening and melting process of iron-bearing materials, such as temperature and pressure drop. However, the role of the chemical reactions during the process, especially the influences of the reducing and slagging reactions participated by wustite and the competition relation between each other are ignored in most of the previous research. Given that, the proposed project firstly determines the interaction between the reducing and slagging reactions participated by wustite under the unsteady state by numerical calculation after a systematic study of the fundamental physical chemistry of the reactions. Then, a comparison is made between the individual and competition reactions of wustite at particular intervals and under different experimental conditions so as to find out the key parameters combining with the macro/micro-characteristics of the process. At last, the influences of inner and external factors on the wustite competition behavior are further investigated and a relation model is developed to discuss the softening and melting mechanism of iron-bearing materials, aiming to supply theoretical guidance and technical support for blast furnace practical production.

高炉软熔带与炉内气流分布和煤气利用密切相关，继而直接影响炉况的顺行与燃料的消耗，研究软熔带的形成机理以获得其合理的形态结构对于高炉操作至关重要。现有的工作重在通过测试含铁炉料的软熔性能，获取表征物理形态变化的温度、压差来评价软熔带的形状及透气性，忽略了内部发生的化学反应，特别是浮氏体还原-成渣反应及其相互间的竞争行为对其形成规律的影响。本项目首先研究浮氏体还原-成渣反应的物理化学基础，并采用非稳态条件下的数值计算来耦合不同反应间的相互作用关系；其次，通过时间历程的纵向切割与实验条件的横向变换，对比研究浮氏体单一与竞争反应条件下所存在的非线性叠加差异，揭示还原-成渣反应间的竞争机理，并结合过程宏/微观特征来凝练关键性的表征参数；最后，深入研究浮氏体内/外不同因素对其竞争行为的影响规律，通过关系模型的构建，进一步明晰含铁炉料的软熔机理，从而为实现高炉的优化生产提供理论指导与技术支持。

本项目探讨了两种浮氏体制备方法及产物的异同点，结合XRD结构精修，分析了温度、时间等对浮氏体非化学计量数的影响规律；基于热力学计算，归纳总结在CO、H2还原气氛和CaO、SiO2、MgO、Al2O3氧化物存在条件下，浮氏体还原成渣平衡态下的主要物相与组成；继而，通过热重法实验研究CO与H2还原浮氏体动力学参数，揭示混合气体还原速率约为单一气体还原速率线性加和结果的76%水平，并通过类比物理电路，提出在外扩散成为限制性环节条件下，气固还原的类电路模型，并设计和引入CO与H2相互作用关系进行修正，获得的I-S-P模型能够预测二元混合煤气的气固还原速率，其误差小于8.5%；接着，以浮氏体为对象，采用荷重软化与熔滴实验，分别研究考察了CaO、SiO2、MgO、Al2O3等氧化物的成渣过程对浮氏体软化及滴落特征的影响规律；最后，进一步通过氧化物的两两组合，实验研究所形成三元渣系在模拟高炉软熔带条件下的软化及滴落特征。在本项目的资助下，发表相关学术论文5篇；获权发明专利1项，申请发明专利1项；参加国内外学术会议4次；已培养毕业研究生1名。此外，本项目还为其它4篇关于颗粒偏析与表征的学术论文研究工作开展提供经费支持。