<I>In-Situ</I> Kinetic Study of Hydrogen Reduction of Fe<SUB>2</SUB>O<SUB>3</SUB> for the Production of Fe Nanopowder

Abstract

The reduction kinetics of Fe 2 O 3 nanopowder was investigated by monitoring the reduction behavior in real-time and measuring the amount of outflowing water vapor using in-situ hygrometry study. The kinetics of hydrogen reduction of Fe 2 O 3 was also studied on the basis of phase transformation, structure modification and outflowing diffusion of water vapor of the Fe 2 O 3 powder during reaction. Activation energy for the hydrogen reduction of Fe 2 O 3 nanopowder was calculated at various heating rate conditions and conversion fraction of reaction. The activation energies for reduction of Fe 2 O 3 nanopowder obtained in this study existed in the range of 20-46 kJ/mol. The activation energy for reduction of Fe 2 O 3 nanopowder obtained in this study decreased from 46 kJ/mol to 20 kJ/mol during the entire reduction process. Therefore, the hygrometry study is a powerful tool for in-situ kinetic study of hydrogen reduction of metal oxide for mass production.

Solid state reaction kinetics of iron oxide reduction using hydrogen as a reducing agent

“…Thus favorable structural characteristics of iron silica MSPS are likely to lower the activation energy for iron oxide reduction. Activation energy values and reaction mechanisms determined in this study are in agreement with those of Pineau et al [5,6], and Jung and Lee [28]. This discussion provides valuable insight into the influence of various parameters on the activation energy, and underscores the need for careful examination of operating conditions used for iron oxide reduction.…”

“…They proposed that, for T>Tt, the wustite phase is present in the reactive substrate and that may influence the reaction kinetics causing a decrease in the activation energy. Jung and Lee [28] studied the reduction of hematite nanoparticles for the production of metallic iron. A gradual decrease in the activation energy from 46 to 35 kJ/mol was observed as the reduction extent increased from 0.1 to 0.8.…”

Consolidation of Hierarchy-Structured Nanopowder Agglomerates and Its Application to Net-Shaping Nanopowder Materials

“…The process involves a two-step procedure consisting of Fe base nanopowder synthesis by hydrogen reduction of oxide precursors [14,15,16,17] and full densification process of PIM nanopowder by pressureless sintering. As depicted in the diagram, the large inter-agglomerate pores should be efficiently minimized by using different processing routes which can control the agglomerate size during the entire process.…”

Design of trimodal Fe micro-nanopowder feedstock for micro powder injection molding

“…In our previous research [21,22], we investigated the kinetics of the hydrogen reduction behavior for Fe 2 O 3 nanopowder agglomerates and provided a fundamental understanding of the microstructural development of the agglomerates during reduction. More recently, we reported the kinetic mechanism of spherically controlled Fe 2 O 3 nanopowder agglomerates during the hydrogen reduction process [23].…”