FORMATION OF HUMBOLDTINE DURING THE DISSOLUTION OF HEMATITE IN OXALIC ACID – DENSITY FUNCTIONAL THEORY (DFT) CALCULATIONS AND EXPERIMENTAL VERIFICATION
Autor: | Bernardo Barbiellini, Bo Gong, Paula Vehmaanperä, Riina Salmimies, Patrick H.-L. Sit, Antti Häkkinen |
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Rok vydání: | 2021 |
Předmět: |
Work (thermodynamics)
Mineral Materials science Oxalic acid Inorganic chemistry Soil Science Hematite Oxalate chemistry.chemical_compound chemistry Geochemistry and Petrology Phase (matter) visual_art Earth and Planetary Sciences (miscellaneous) visual_art.visual_art_medium Density functional theory Dissolution Water Science and Technology |
Zdroj: | Clays and Clay Minerals. 69:655-662 |
ISSN: | 1552-8367 0009-8604 |
DOI: | 10.1007/s42860-021-00146-5 |
Popis: | Understanding the reactions taking place in the hematite-oxalic acid system is important in order to clean iron oxides from filters and to remove iron from mineral concentrates. Previous studies reported the formation of an unwanted solid phase during this process. The objective of the current work, therefore, was to visualize and rationalize the iron dissolution steps taking place in the hematite–oxalic acid reaction by combining density functional theory (DFT) calculations and experimental data. The results of DFT calculations indicated that a precipitate was formed in this reaction; XRD analysis of the solid phase after the dissolution experiment revealed the formation of humboldtine as the precipitate. The attachment of oxalate on the hematite surface and the reduction of Fe(III) to Fe(II) were key steps for humboldtine formation. Both simulations and the experimental results showed that greater oxalic acid concentrations yielded more precipitate, suggesting a simple and novel route to synthesize humboldtine, a material which is relevant to the demand for clean energy. |
Databáze: | OpenAIRE |
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