The iron and steel industry is a major CO₂ emitter and an important subject for the implementation of carbon emission reduction goals and tasks. Due to the complex ore composition and low iron grade, vanadium–bearing titanomagnetite smelting in a blast furnace consumes more coke and emits more carbon than in an ordinary blast furnace. Injecting hydrogen–rich gas into blast furnace can not only partially replace coke, but also reduce the carbon emission. Based on the whole furnace and zonal energy and mass balance of blast furnace, the operation window of the blast furnace smelting vanadium–bearing titanomagnetite is established in this study on the premise that the thermal state of the blast furnace is basically unchanged (raceway adiabatic flame temperature and top gas temperature). The effects of different injection amounts of hydrogen–rich gases (shale gas, coke oven gas, and hydrogen) on raceway adiabatic flame temperature and top gas temperature, and the influence of blast temperature and preheating temperature of hydrogen–rich gases on operation window are calculated and analyzed. This study provides a certain theoretical reference for the follow–up practice of hydrogen–rich smelting of vanadium–bearing titanomagnetite in blast furnace.

Blast furnace–basic oxygen furnace (BF–BOF) process is the predominant method for smelting vanadium titano-magnetite (VTM) in China. Hydrogen-rich (H₂-rich) gas injection in BF is considered as an important way to reduce CO₂ emission under the background of low carbon metallurgy. In this paper, the softening–melting behaviors of VTM sinter in H₂–rich gases were investigated by the method of determination of its reduction softening drippinger performance under load. The experimental results indicated that the permeability of VTM sinter during the softening–melting process was improved by increasing the H₂ content of the reducing gases. The maximum pressure drop of the burden decreased gradually from 29.76 kPa to 19.97 kPa, and the total characteristic value (representing the comprehensive softening–melting property) also decreased obviously from 2357.52 kPa·°C to 630.94 kPa·°C with the increase in H₂ content. The softening interval of the samples was widened, while the melting–dripping interval increased firstly and then decreased. In that case, the position of the melting–dripping zone in BF would move downwards, which was beneficial to smelting smoothly. The thermodynamic analysis indicated that Ti- and Fe-bearing phases were more difficult to be reduced than iron oxides, and H₂-rich gas is beneficial to the reduction of that kind of oxides. Titano-magnetite will be reduced stepwise to form Fe₂TiO₄, and then in the order of FeTiO₃→TiO₂→Ti(C,N). Wustite (FeO) was an important component during the slag-forming process, whose content increased firstly and then decreased. Perovskite and silicate were the main phases in the dripping slag samples.