Wall reduction and heat transfer characteristics of captured iron ore particles during flash ironmaking process

ABSTRACT

The wall reaction and heat transfer characteristics of captured particles in the flash ironmaking reactor are essential to the reduction degree and liquid phase flow. In-situ studies of near-wall reduction were conducted using a high-temperature hot-stage microscope. Furthermore, a mathematical model was established for analyzing heat and mass transfer in iron ore particles. Results showed that above 1642 K, haematite particles partially melted, forming a bilayer structure with a molten ring and unmolten core as the liquid intermediate product spread rapidly. Higher gas flowrates prolonged melting product diffusion time. The liquid intermediate product volume predicted by the mathematical model matched well with the experimental data. Computational analysis revealed fluctuating particle temperatures during the reaction process, with the degree influenced by the reaction rate. Fluctuations increased with higher CO gas flowrate, particle size, and gas temperature, with gas temperature being the most influential factor.

KEYWORDS:

• Flash ironmaking
• captured iron ore particle
• wall reaction
• gas flowrate
• liquid intermediate product
• partial melting
• heat and mass transfer
• particle temperature

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Shanghai Pujiang Program (21PJ1402300) [grant number 21PJ1402300]; Chinese Postdoctoral Science Foundation [grant number 2021TQ0108, 2022M711151]; Open Research Fund of State Key Laboratory of Multiphase Complex Systems [grant number No. MPCS-2021-D-07].