高铬型钒钛磁铁矿气基还原-熔分复杂体系钛、钒、铬的耦合作用机制

High chromium vanadium-titanium magnetite is a typical refractory composite mineral resource with high comprehensive utilization value. The short flow of gas - based shaft furnace is a new direction of transformation and upgrading of iron and steel industry in China. With the increasing requirements of the strategic resources including titanium, vanadium, and chromium, it is of great significance to develop the efficient and clean comprehensive utilization process and the corresponding key basic theory for high chromium vanadium-bearing titanomagnetite. Based on the novel process of gas-based shaft furnace direct reduction-melting separation for high chromium vanadium-bearing titanomagnetite, and aiming at establishing the coupling mechanism of titanium, vanadium, and chromium in the complex system during the new process, the interaction influences of titanium, vanadium, chromium components on the thermodynamics and kinetics, phase transition, mineral refactoring, and microstructure of minerals during the three key processes of oxidation roasting, gas-based reduction, and melting separation are studied. And the quantitative characterization models between the titanium, vanadium, chromium components and pellet micromechanical properties, compressive strength, reduction swelling, thermal sticking are established. In addition, the synergistic effects of titanium, vanadium and chromium on the balance and distribution behavior at the iron-slag interface and the rheological properties of melting separation slag are revealed. Moreover, the valuable components mass action concentration model and viscosity prediction model for the multivariate and multiphase coupled slag are established. The researches will improve the theoretical system of comprehensive utilization for high chromium vanadium-bearing titanomagnetite and lay a foundation for the efficient and clean large-scale exploitation and utilization of this mineral resource.

高铬型钒钛磁铁矿是极具综合利用价值的典型难处理复合矿产资源。气基竖炉短流程是我国钢铁工业转型升级的新方向。随着钒、钛、铬等战略资源的需求日益增加，研发高铬型钒钛磁铁矿高效清洁综合利技术和关键基础理论意义重大。本项目围绕高铬型钒钛磁铁矿气基竖炉直接还原-熔分新工艺，以阐明复杂体系钛、钒、铬的耦合作用机制为目标，重点研究钛、钒、铬对氧化焙烧、气基还原、熔分三个关键过程反应热力学及动力学、物相迁移、三维矿物重构、微观组织显微形态演变的交互作用规律，构建钛、钒、铬组元含量与球团显微力学性能、抗压强度、还原膨胀、热结的关联模型，揭示钛、钒、铬对熔分渣-金界面分配行为及熔分渣流变特性的协同影响机理，创建多元多相耦合的熔分渣有价组元作用浓度模型和黏度预测模型，完善高铬型钒钛磁铁矿综合利用理论体系，为该资源高效清洁大规模开发利用奠定基础。

高铬型钒钛磁铁矿是典型的多金属共生复合矿，结构复杂，加工利用难度大。目前气基竖炉短流程是我国冶炼高铬型钒钛磁铁矿的新方向。随着钒、钛、铬等战略资源的需求日益增加，积极开发高铬型钒钛磁铁矿清洁高效综合利用是我国战略规划的重要内容。本研究以高铬型钒钛磁铁矿资源高效清洁综合利用为核心目标，围绕高铬型钒钛磁铁气基竖炉直接还原-熔分新工艺，充分结合多学科理论、现代测试技术及工具软件，系统研究了钛、钒、铬对新工艺复杂体系氧化焙烧、气基还原、熔分行为及矿物重构的耦合作用机制，实现新工艺理论创新，有助于高铬型钒钛磁铁矿高效清洁大规模开发，促进我国钢铁工业绿色低碳可持续发展。研究结果表明钛会恶化球团氧化动力学条件，钒和铬均会改善球团氧化动力学条件。钛和钒均会导致球团内部孔洞增多。钛、钒、铬均会对球团矿氧化产生一定的不利影响，降低球团抗压强度和显微硬度。钛、钒、铬均能不同程度地提高氧化球团中赤铁矿的断裂韧性。钛、钒、铬组元均会恶化球团的还原动力学条件，并且均会在还原过程中产生难还原物相。钛组元会抑制球团的粘结作用，相反铬、钒均会加剧球团的粘结作用。钛、钒、铬组元均会使球团在还原过程中膨胀率呈现先增大后减小的趋势。钛、钒、铬对熔分过程热力学有较大影响，有价组元氧化物或矿物的还原反应生成金属单质的难度要比生成对应的碳化物和低价氧化物困难。有价组元对熔分渣流变特性有较大的影响，其中TiO2质量分数增大，实验渣系黏度降低，Cr2O3和V2O3的加入会使熔分渣的粘度明显增大。当CaO/Al2O3值大于１时，加入一定量的TiO2，能够降低熔渣的完全熔化温度。