Numerical Investigation into Gas-Particle Inter-Phase Combustion and Reduction in the Flash Ironmaking Process

Abstract

Despite the dominance of the blast furnace ironmaking process, more attention is being paid to the new technologies with lower energy consumption and carbon dioxide emissions. A novel flash ironmaking technology using pulverized coals and iron concentrates as raw materials, which is different from flash ironmaking with the reductive gas as the reducing agent, is studied. In order to obtain the flow patterns, temperature, and gas composition distribution, as well as particle trajectories in the reaction shaft of the flash ironmaking furnace, the Euler–Lagrangian model with a custom user defined function (UDF) code is used to simulate the processes of the fluid flow, heat and mass transfer, and chemical reactions, including the combustion reaction of pulverized coals and reduction reaction of iron concentrates. The results indicate that the flow patterns, temperature, and gas composition distributions present symmetrical distribution characteristics. The central oxygen expands rapidly after entering the reaction shaft and its distribution is approximately bell-shaped. The temperature distribution in the reaction shaft is wing-shaped. The maximum temperature, 2615 K, is reached at 5 m below the roof of the reaction shaft. The O2 is quickly consumed after entering the reaction shaft. At 6 m below the roof of the reaction shaft, the oxygen concentration becomes almost zero, with the CO concentration reaching the highest. The Fe2O3 and FeO in the iron concentrates are mostly reduced to Fe at 9 m below the roof of the reaction shaft, and more than 95 wt% iron particles could be obtained within 1.2–7.7 s.

Keywords

• flash ironmaking
• reaction shaft
• smelting process
• numerical simulation