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Carbon-infiltrated iron ores were prepared from a coal-tar solution and selected calcined iron sources (i.e., goethite (FeOOH) ore, high-grade hematite ore, and FeO reagent grain). A several hundred micrometer thick carbon layer was deposited on the surface of all iron sources. Because the tar solution successfully penetrated into its nanopores, only goethite ore possessed a significant amount of carbon in its interior nanopores. The carbon-infiltrated ores were heated rapidly in an oxygen atmosphere in the combustion synthesis experiments. Carbon combustion occurred at the ore surface, with the ore temperature increasing suddenly during the experiments. Fast reduction to metallic iron was observed only in the carbon-infiltrated goethite ore, regardless of the oxygen atmosphere. Close contact between the goethite ore and the carbon in its nanoporous interior facilitated the fast reduction. The apparent reduction reaction of goethite ore is akin to a direct reduction reaction (i.e., FeO + C → FeO + CO).
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http://dx.doi.org/10.1021/acsomega.8b00958 | DOI Listing |
J Hazard Mater
September 2025
Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Petroleum Resources Exploration and Evaluation, Gansu Province, Lanzhou 730000, China; Key Laboratory of Strategic Mineral Resources of the Upper Yellow River, Ministry of Natu
Uranium (U) contamination poses a significant environmental threat due to its mobility, radiotoxicity, and persistence in water bodies near mining and ore-processing sites. In sulfidic and anoxic conditions common to these settings, the sulfidation of iron (hydr)oxides may play a key role in the transformation and immobilization of U(VI) and iron (hydr)oxides, yet the mechanisms remain poorly understood. In this study, we systematically examined the reaction mechanisms between U(VI) and ferrihydrite in the presence of S under anaerobic conditions.
View Article and Find Full Text PDFEnviron Pollut
June 2025
State Key Laboratory of Soil Pollution Control and Safety, Zhejiang University, Hangzhou, Zhejiang, 310058, China; College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hang
The reoccurrence of Cr(VI) in reduced chromium ore processing residue (rCOPR) causes secondary pollution after remediation, with Mn(II)-induced catalytic oxidation identified as one of its key contributors. The mineral transformation of Cr-Fe coprecipitate (CrFe(OH) dominant phase in rCOPR) tends to form goethite along with Cr(III) in alkaline environments. However, the effect of this critical process on Cr(VI) reoccurrence remains unknown and requires further investigation.
View Article and Find Full Text PDFLangmuir
March 2025
CNRS, GeoRessources, Université de Lorraine, F54000 Nancy, France.
Chemical dispersion has been commonly used to mitigate the negative effects of ultrafine particles in iron ore concentration processes. However, mechanical solutions such as ultrasound are proving to be more effective and without harmful side effects. This study compared the performance of different dispersants and ultrasound as pretreatments for reverse cationic flotation of goethite-rich slime tailings through sedimentation, dispersion, and flotation tests, along with particle size analysis.
View Article and Find Full Text PDFJ Environ Manage
April 2025
College of Environmental Science and Engineering, Shaanxi University of Science and Technology, China. Electronic address:
Microbial dissimilated iron reduction is one of the important driving forces of the biological and geochemical cycles of iron in nature. Plant root exudates dominated by organic acids are important electron donors of the rhizosphere dissimilar iron reduction microorganisms under flooded conditions. In this paper, we investigated the effects of different kinds and concentrations of organic acids on the dissimilation reduction process of goethite by Shewanella oneidensis MR-1, and explored the effect of phase transformation of iron minerals on its adsorption of Cd.
View Article and Find Full Text PDFSci Rep
February 2025
Geology Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
The present study combines remote sensing data (Landsat-8 and ASTER) with structural analysis to identify the fault systems affecting the distribution of the ironstone beds in northeastern Aswan, Egypt. Sedimentary rocks, such as the Abu Aggag, Timsah, and Umm Brammily formations, characterize northeastern Aswan. The Abu Aggag Formation consists of kaolinitic conglomerate, conglomeratic sandstone, and mudstone.
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