| 1. |
- Zou, Yonggang, et al.
(författare)
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Rotational dynamics of confined C60 from near-infrared Raman studies under high pressure
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:52, s. 22135-22138
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Tidskriftsartikel (refereegranskat)abstract
- Peapods present a model system for studying the properties of dimensionally constrained crystal structures, whose dynamical properties are very important. We have recently studied the rotational dynamics of C60 molecules confined inside single walled carbon nanotube (SWNT) by analyzing the intermediate frequency mode lattice vibrations using near-infrared Raman spectroscopy. The rotation of C60 was tuned to a known state by applying high pressure, at which condition C60 first forms dimers at low pressure and then forms a single-chain, nonrotating, polymer structure at high pressure. In the latter state the molecules form chains with a 2-fold symmetry. We propose that the C60 molecules in SWNT exhibit an unusual type of ratcheted rotation due to the interaction between C60 and SWNT in the “hexagon orientation,” and the characteristic vibrations of ratcheted rotation becomes more obvious with decreasing temperature.
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| 2. |
- Ye, Lei, et al.
(författare)
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Preparation of Metallized Pellets from Blast Furnace Dust and Electric Arc Furnace Dust Based on Microwave Impedance Matching
- 2020
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Ingår i: 11th International Symposium on High-Temperature Metallurgical Processing. - Cham : Springer Nature. - 9783030365400 - 9783030365394 ; , s. 569-579
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Konferensbidrag (refereegranskat)abstract
- Blast furnace dust and electric arc furnace dust are two typical solid wastes in iron and steel industry. In order to overcome the shortcomings of traditional processes, such as low metal recovery efficiency and high secondary pollution, microwave energy was applied in this study to intensify the self-reduction of core-shell BF dust-EAF dust composite pellets based on impedance matching for realizing highly efficient migration and separation of iron, zinc, and lead. By reducing the composite pellets in microwave field, it was found that under the optimal conditions of proportion of EAF dust in shell to all EAF dust in the pellet of 20%, reduction temperature of 1000 degrees C, and dwell time of 15 min, metallized pellets with the total iron content of 68.73 wt %, iron metallization degree of 95.87%, zinc removal percentage of 88.78%, lead removal percentage of 94.38%, and compressive strength of 190.4 N/p were obtained.
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| 3. |
- Ye, Lei, et al.
(författare)
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Toward environmentally friendly direct reduced iron production : A novel route of comprehensive utilization of blast furnace dust and electric arc furnace dust
- 2021
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 135, s. 389-396
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a novel method for producing direct reduced iron (DRI) powders based on microwave-assisted self reduction of core-shell composite pellets composed of blast furnace (BF) dust and hazardous electric arc furnace (EAF) dust followed by magnetic separation was reported. The proper core-shell structure of the composite pellets was designed according to the rule of impedance matching and properties of BF dust and EAF dust by adjusting the thickness of shell (i.e., thickness of impedance matching layer) via controlling the C/O molar ratio of the raw materials from 0.55 to 0.70. The results showed that the EAF dust with high content of CaO was beneficial to the mechanical strength of green, dried, and metallized pellets (collected after reduction), while the BF dust with high content of carbon enabled sufficient microwave-assisted reduction of the pellets, facilitating subsequent magnetic separation and also the removal of zinc from EAF dust. By reduction of the core-shell BF dust-EAF dust composite pellets with the C/O molar ratio of 0.65 at 1050 degrees C for 15 min, the resulting metallized pellets showed superior reduction and magnetic separation indexes with higher removal percentages of zinc and lead, in comparison with conventional metallized pellets. The DRI powders obtained after magnetic separation had total iron content of 91.2 wt%, iron metallization degree of 95.8%, yield of 68.1%, and iron recovery of 88.0%. This study provided a good example for efficient and environmentally friendly comprehensive utilization of typical and hazardous wastes in the iron and steel industry.
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| 4. |
- Ye, Qing, et al.
(författare)
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Thermodynamic Analysis of Carbothermic Reduction of Electric Arc Furnace Dust
- 2019
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Ingår i: 10th International Symposium On High-Temperature Metallurgical Processing. - Cham : Springer International Publishing. - 9783030059552 - 9783030059545 ; , s. 117-124
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Konferensbidrag (refereegranskat)abstract
- Electric arc furnace (EAF) dust is a kind of secondary resource which contains multiple metallic elements, including Fe, Mn and Cr. Pyrometallurgical processes for recovering metal elements from EAF dust have been investigated for many years although they are suffered from high energy consumption due to the spinel-structured components of EAF dust. In this study, the thermodynamic analysis of carbothermic reduction of EAF dust was performed. The main components of EAF dust were magnetite (Fe3O4), hausmannite (Mn3O4) and chromate spinel (FeCr2O4). The gangue minerals were mainly composed of magnesium silicates. The thermodynamic analysis indicated that magnetite and hausmannite can be reduced to metallic iron and MnO, respectively. Meanwhile, the chromate spinel will be reduced to chromium oxide and then to form CaCr2O4. The results also demonstrated that the gangue components can promote the separation of Fe and Cr, agreeing well with the experimental results.
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