Numerical simulation of flash reduction process of hematite powder in H2 atmosphere

To gain insights into the flash reduction process of hematite powder in H2 atmospheres, a three-dimensional Euler-Lagrange model was developed for the laboratory flash reduction furnace. The effects of key operating parameters on the gas flow field, temperature distribution, particle motion, and hematite reduction behavior were investigated. The length and temperature of the key reaction zone can be significantly elevated by increasing the H2 concentration from 10% to 90% or furnace temperature from 1400 K to 1800 K. Due to the influence of the jet flow, the hematite particles gradually deviate from the central axis in the upper part of the reaction zone, while they move almost vertically downward in the lower section. The reduction process at 1800 K is composed of five stages: the delay reaction stage, the thermal decomposition accompanied with gas-solid reduction stage, the gas-solid reduction stage, the gas-liquid reduction stage, and the complete reduction stage.