Affiliation:
1. State Key Laboratory of Advanced Special Steels, Key Laboratory of Modern Metallurgy and Material Preparation, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
Abstract
The mineral surface structure and ions’ interaction were of significant interest to understanding mineral dissolution and reaction. In this study, X-ray photoemission spectroscopy combined with ICP emission spectrometer was used to investigate the influence of the leaching reaction conditions of 8 M dilute sulfuric acid and 12 M concentrated sulfuric acid on the surface chemical composition, chemical (valence) state and ion distribution of Columbite-(Fe) (FeNb2O6). The binding energy of the cations (Fe, Nb) bonding with different anions (O2−, SO42−) and the ratio of Fe3+/Fe2+ oxidation–reduction provided direct understanding of Fe and Nb releasing from the mineral surface during leaching. The results showed that the binding energy of the Nb5+-O bond was much smaller than that of Nb5+-SO4, and the binding energy decreased in sequence as Nb5+-O < Fe2+-O < Fe3+-O and increased in sequence as Fe3+-SO4 < Fe2+-SO4 < Nb5+-SO4. The mineral surface reaction during the leaching could be expressed with the formula: Fe-O + H2SO4 → Fe-SO4 + H2O, Nb-O + H2SO4 → Nb-SO4 + H2O. The results also revealed that Nb dissolution from Columbite-(Fe) occurred more easily compared to Fe. Nb dissolution from the mineral was owed to the content of H+ in solution, and increasing the H+ concentration could promote the dissolution. For Fe dissolution from the mineral, the oxidation potential could play an effective role in enhancement dissolution.
Funder
National Natural Science Foundation of China
Subject
Geology,Geotechnical Engineering and Engineering Geology
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