# Reaction Behavior of Ultrafine Ferric Oxide Powder with Hydrogen–Carbon Monoxide Gas Mixture

## TL;DR

This study investigates how ultrafine ferric oxide reacts with hydrogen and carbon monoxide gases to improve ironmaking processes.

## Contribution

The paper establishes a relationship between gas composition and reaction rate during iron oxide reduction using a single-step nucleation model.

## Key findings

- Low hydrogen content (<30%) at 1023 K leads to significant carbon deposition during reduction.
- Gas composition strongly influences the reaction rate in the FeO to Fe stage.
- Apparent activation energy ranges from 20–45 kJ/mol, suggesting gas diffusion and chemical reaction as rate-controlling steps.

## Abstract

This study aims to enhance fundamental research on the reaction behavior between ferric oxide and H2–CO gas mixtures and to provide theoretical support for optimizing the injection of hydrogen-containing materials in the ironmaking process. In this study, the ultrafine ferric oxide powder was isothermally reduced with H2–CO gas mixture at 1023 K–1373 K. The results indicated that when H2 content is less than 30% at 1023 K, the ferric oxide sample reduced by the H2–CO gas mixture exhibits a pronounced carbon deposition phenomenon during the reduction stage. The gas reactant composition had a relatively large influence on the reaction rate at the third stage of the reduction reaction (FeO → Fe). Assuming the single-step nucleation assumption theory together with kinetic experimental data, the relationship between the average reaction rate and the gas composition of the H2–CO gas mixture was established for the FeO reduction stage. In addition, the apparent activation energy of the reduction reaction was generally in the range of 20–45 kJ/mol, indicating that the possible rate-controlling step was combined gas diffusion and interfacial gas–solid chemical reaction.