Role of water in hydrogen-based iron oxide reduction: effects on pore evolution and gas transport
Year: 2026
Type: preprint
Abstract: Hydrogen-based direct reduction offers a low-emission route to ironmaking. Oxygen removal reduces the mass and volume of the solid, creating pores that provide pathways for hydrogen supply and removal of the water produced. Water accumulation within these evolving pores can inhibit further reduction. Here, we develop a phase-field model coupling water generation, transport, and reaction inhibition to pore evolution during wüstite-to-ferrite reduction. The simulations show that water accumulation slows reduction and allows pores to coarsen. Increasing the pore volume fraction accelerates reduction but does not prevent water accumulation when its removal from the pores is limited. Simulating gas diffusion through the resulting fixed pore structures shows that coarser morphologies have higher directional effective diffusivity even at comparable pore fractions. These findings motivate pellet-scale models that account for how reduction history shapes pore morphology and thereby influences gas transport.
Source: ChemRxiv
Language: English
Subfield: Metals and Alloys
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223649994