Zhenyang Wang

The oxygen blast furnace (OBF) process provides a promising pathway for the efficient and low-carbon smelting of vanadium–titanium magnetite (VTM). In this study, Ti(C,N) precipitation in hot metal under OBF conditions was systematically investigated through thermodynamic analysis, in situ confocal scanning laser microscopy (CSLM), and molecular dynamics (MD) simulations. Thermodynamic calculations show that decreasing the N₂ mole fraction increases the critical Ti content required for Ti(C,N) precipitation while reducing the equilibrium amount of precipitated Ti(C,N). At an N₂ mole fraction of 1%, the theoretical equilibrium amount of precipitated Ti(C,N) decreases by 57%. CSLM observations further reveal that OBF conditions suppress the nucleation, growth, and agglomeration of Ti(C,N), thereby decreasing the average equivalent particle size compared with conventional blast furnace conditions. MD simulations reveal that the lower nitrogen content reduces Ti–N coordination and inhibits the formation and sustained growth of TiN clusters, resulting in smaller and less stable clusters with higher average atomic energies.

The softening and melting behavior of iron ore is a critical parameter that affects the efficiency of the blast furnace ironmaking process. In order to gain a deeper understanding of the melting behavior of iron ore particles from a kinetic perspective, a three-dimensional model for the melting process of iron ore particles was established to study the effects of particle size, initial temperature, gas flow velocity, and temperature on the phase transformation and heat transfer process of iron ore particles. The simulation results indicate that the particle size has the most significant impact on the phase transformation and heat transfer process. The use of smaller particles is beneficial for improving heat transfer capacity and melting rate, reducing the thickness of the cohesive zone, and improving production efficiency. In addition, the gas flow rate mainly affected the time when iron ore particles begin to melt. As the velocity of gas flow increases and the initial temperature difference between the gas and iron ore increases, the heat transfer ability is enhanced, and the migration speed of the liquid phase interface is accelerated. The results of this study could help to improve the efficiency of the blast furnace ironmaking process by providing a better understanding of the phase transformation process of iron ore particles under different environmental condition.