| 1. |
- Abbasalizadeh, Aida, et al.
(författare)
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Highlights of the Salt Extraction Process
- 2013
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 65:11, s. 1552-1558
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Tidskriftsartikel (refereegranskat)abstract
- This article presents the salient features of a new process for the recovery of metal values from secondary sources and waste materials such as slag and flue dusts. It is also feasible in extracting metals such as nickel and cobalt from ores that normally are difficult to enrich and process metallurgically. The salt extraction process is based on extraction of the metals from the raw materials by a molten salt bath consisting of NaCl, LiCl, and KCl corresponding to the eutectic composition with AlCl3 as the chlorinating agent. The process is operated in the temperature range 973 K (700 degrees C) to 1173 K (900 degrees C). The process was shown to be successful in extracting Cr and Fe from electric arc furnace (EAF) slag. Electrolytic copper could be produced from copper concentrate based on chalcopyrite in a single step. Conducting the process in oxygen-free atmosphere, sulfur could be captured in the elemental form. The method proved to be successful in extracting lead from spent cathode ray tubes. In order to prevent the loss of AlCl3 in the vapor form and also chlorine gas emission at the cathode during the electrolysis, liquid aluminum was used. The process was shown to be successful in extracting Nd and Dy from magnetic scrap. The method is a highly promising process route for the recovery of strategic metals. It also has the added advantage of being environmentally friendly.
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| 2. |
- Persson, Mikael, et al.
(författare)
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Kinetic studies of fluoride evaporation from slags
- 2007
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 47:12, s. 1711-1717
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Tidskriftsartikel (refereegranskat)abstract
- In view of the environmental problems associated with the evaporation of fluoride from slags and fluxes, a systematic study of the fluoride emission from slags at temperatures, relevant to steelmaking and casting, has been initiated in the present work. The loss of fluoride from slag melts was monitored by Thermogravimetric Analysis (TGA). The present paper reports the fluoride evaporation in the three binary systems Al2O3-SiO2, CaC-SiO2 and MgO-SiO2 with additions of CaF2 (ca. 3.5, 5 and 9 wt%). The thermogravimetric experiments were carried out in argon atmosphere in the isothermal mode in the temperature range 1673-1873 K. The gas flow was kept above the starvation rate in order to avoid the gas phase mass transfer step. From the results, the Arrhenius activation energies for the evaporation reaction were evaluated. The activation energies were found to be dependent on temperature and slag chemistry for the various slags studied. In binary systems, the activation energy for fluoride evaporation was found to depend on the square of the activity of SiO2 in the slag melt. This correlation obtained in the case of the binary systems could be validated in the case of the results obtained for the ternary system Al2O3-CaO-SiO2 with 5 and 10 wt% of CaF2, The present results are considered to be useful in estimating the fluoride emissions from industrial slags and mould fluxes.
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| 3. |
- Seetharaman, Seshadri, et al.
(författare)
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Treatise on Process Metallurgy
- 2024
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Treatise on Process Metallurgy: Volume One, Process Fundamentals provides academics with the fundamentals of the manufacturing of metallic materials, from raw materials into finished parts or products. In these fully updated volumes, coverage is expanded into four volumes, including Process Fundamentals, encompassing process fundamentals, structure and properties of matter; thermodynamic aspects of process metallurgy, and rate phenomena in process metallurgy; Processing Phenomena, encompassing interfacial phenomena in high temperature metallurgy, metallurgical process phenomena, and metallurgical process technology; Metallurgical Processes, encompassing mineral processing, aqueous processing, electrochemical material and energy processes, and iron and steel technology, non-ferrous process principles and production technologies, and more. The work distills the combined academic experience from the principal editor and the multidisciplinary four-member editorial board.
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| 4. |
- Semykina, Anna, 1986-, et al.
(författare)
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Confocal Microscopic Studies on Evolution of Crystals during oxidation of the FeO-CaO-SiO2-MnO Slags
- 2010
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Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Science and Business Media LLC. - 1073-5615 .- 1543-1916. ; 41:5, s. 940-945
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Tidskriftsartikel (refereegranskat)abstract
- The current work investigates dynamic phenomena at the microstructural level during iron and manganese recovery from the liquid FeO-CaO-SiO2-MnO slags using an oxidation method. A hot-stage-equipped confocal scanning laser microscope (CSLM) was used to analyze the kinetic behavior of crystallization in synthetic slags. Based on observed precipitations on cooling in the 1273 K (1000 °C) to 1873 K (1600 °C) temperature range, a time–temperature–transformation (TTT) diagram has been created. The crystallization studies were conducted in air.
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| 5. |
- Semykina, Anna, 1986-, et al.
(författare)
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Confocal Scanning Laser Microscopy studies of crystal growth during oxidation of a liquid FeO-CaO-SiO2 slag
- 2011
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Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Science and Business Media LLC. - 1073-5615 .- 1543-1916. ; 42:3, s. 471-476
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Tidskriftsartikel (refereegranskat)abstract
- The oxidation of FeO in 30 wt pct FeO-35 wt pct CaO-35 wt pct SiO2 slag was investigated as part of a wider study on the recovery of Fe units through magnetic separation. A confocal scanning laser microscopy (CSLM) technique was used to visualize the oxidation of FeO in the liquid slag. The formation event was observed in situ under the CSLM and the onset of precipitation on a surface of the slag liquid was recorded at various temperatures in an oxidizing atmosphere. A Time-Temperature-Transformation (TTT) diagram was constructed based on the CSLM results. Samples obtained from the CSLM heating chamber were analyzed by a scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS).
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| 6. |
- Sun, Yongqi, et al.
(författare)
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A Fe-C-Ca big cycle in modern carbon-intensive industries : toward emission reduction and resource utilization
- 2016
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Herein a big Fe-C-Ca cycle, clarifying the basic element flows and energy flows in modern carbon-intensive industries including the metallurgical industry and the cement industry, was proposed for the first time in the contexts of emission reduction and iron ore degradation nowadays. This big cycle was focused on three industrial elements of Fe, C and Ca and thus it mainly comprised three interdependent loops, i.e., a C-cycle, a Fe-cycle and a Ca-path. As exemplified, we started from the integrated disposal of hot steel slags, a man-made iron resource via char gasification and the employment of hematite, a natural iron resource greatly extended the application area of this idea. Accordingly, based on this concept, the theoretical potentials for energy saving, emission reduction and Fe resource recovery achieved in modern industry are estimated up to 7.66 Mt of standard coal, 63.9 Mt of CO2 and 25.2 Mt of pig iron, respectively.
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| 7. |
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| 8. |
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| 9. |
- Abbasalizadeh, Aida, et al.
(författare)
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Electrochemical Extraction of Rare Earth Metals in Molten Fluorides : Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives
- 2017
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Ingår i: JOURNAL OF SUSTAINABLE METALLURGY. - : SPRINGER. - 2199-3823 .- 2199-3831. ; 3:3, s. 627-637
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Tidskriftsartikel (refereegranskat)abstract
- In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation of oxyfluorides in the fluorination process. Based on thermodynamic calculations, a series of experiments were performed for converting the rare earth oxides into rare earth fluorides using AlF3, ZnF2, FeF3, and Na3AlF6 as fluorinating agents in a LiF-Nd2O3 system. The formation of neodymium fluoride as a result of the reactions between these fluxes and neodymium oxide is confirmed. The rare earth fluoride thus formed can subsequently be processed through the electrolysis route in the same reactor, and rare earth metal can be produced as the cathodic deposit. In this concept, the REO dissolution in molten fluorides would become unnecessary due to the complete conversion of the oxide into the fluoride, REF3. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2, and FeF3 can act as strong fluorinating agents for the neodymium oxide giving rise to a complete conversion of neodymium oxide into neodymium fluoride.
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| 10. |
- Abbasalizadeh, Aida, et al.
(författare)
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Electrochemical Recovery of Rare Earth Elements from Magnets : Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts
- 2017
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Ingår i: Materials transactions. - : JAPAN INST METALS. - 1345-9678 .- 1347-5320. ; 58:3, s. 400-405
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, selective extraction of rare earth (RE) metals from NdFeB magnets is investigated by studying the effects of various fluxes, viz. AlF3, ZnF2, FeF3 and Na3AlF6 in the LiF-NdFeB system. The aim is to convert RE from RE magnet into the fluoride salt melt. The results show the complete selective separation of neodymium (also dysprosium) from the magnet and formation of rare earth fluoride, leaving iron and boron unreacted. The formed rare earth fluoride can subsequently be processed in the same reactor through an electrolysis route so that RE can be deposited as a cathode product. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2 and FeF3 can act as strong fluorinating agents for extraction of rare earth from NdFeB magnet, converting the RE to REF3. The results confirm the feasibility of the rare earth metals recovery from scrap NdFeB magnet as raw material. The fluoride conversion- electrolysis route suggested in the present work enables the extraction of rare earth metals in a single step using the above-mentioned fluxes.
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