Dissolution of Iron Oxides Highly Loaded in Oxalic Acid Aqueous Solution for a Potential Application in Iron-Making

Phatchada Santawaja, Shinji KUDO, Atsushi Tahara, Shusaku ASANO, Jun Ichiro HAYASHI

研究成果: ジャーナルへの寄稿学術誌査読

1 被引用数 (Scopus)


Oxalic acid has been identified as a sustainable chemical enabling an efficient recovery of target metals from industrial minerals by dissolution. The dissolution process recently has attracted attention as a key reaction in a potential clean iron-making. In this application to efficiently produce a high-purity iron, the dissolution is required to occur in the absence of light, with no addition of other chemical reagents, and to produce high concentration iron oxalate aqueous solution as fast as possible. To reveal the chemistry of iron oxide dissolution for this application, in the present study, the dissolution experiments are carried out under various conditions with a particular focus on the iron oxide highly loaded in the oxalic acid aqueous solution. Highly acidic oxalic acid solution for dissolving the highly loaded iron oxide enabled the production of iron oxalates aqueous solution with the concentration of up to 0.56 mol-Fe/L. Different from conventional studies under diluted conditions with pH control, the dissolution followed a non-reductive mechanism, producing [Fe3+HC2O4]2+ as a dominant iron species, and highly correlated with a concentration of proton in the solution. The experimental results and proposed stoichiometries identified a minimum amount of oxalic acid required for the complete dissolution of iron oxide independently from the concentration and type of loaded iron oxide. Among iron oxides tested (α-Fe2O3, FeOOH and Fe3O4) as the feedstock, Fe3O4 had an advantage in the dissolution rate, but showed a relatively low iron recovery in the solution (80-90%) because of an unavoidable formation of FeC2O4 2H2O precipitates.

ジャーナルisij international
出版ステータス出版済み - 12月 2022

!!!All Science Journal Classification (ASJC) codes

  • 材料力学
  • 機械工学
  • 金属および合金
  • 材料化学


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