Confocal Scanning Laser Microscopy Studies of Crystal Growth During Oxidation of a Liquid FeO-CaO-SiO2 Slag

Semykina, Anna; Nakano, Jinichiro; Sridhar, Seetharaman; Shatokha, Volodymyr; Seetharaman, Seshadri

doi:10.1007/s11663-011-9505-6

Cited by 38 publications

(24 citation statements)

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“…The average diameter of magnetite particles was about 10 μm when the temperature reached 1623 K. The diameter of the particles, accompanied by some tiny particles, increased to 20 μm when the holding time was 20 min, while the crystal size grew slightly when the holding time was longer than 20 min. This result was similar to the findings for oxidation of FeO-CaO-SiO2 slag systems [7].…”

Section: Influence Factors On the Crystallization Of Magnetitesupporting

confidence: 91%

“…Zhang [6] studied the oxidation mechanism of CaO-FeOx-SiO2 slag with high iron content in a pure oxygen atmosphere. The crystal growth during oxidation of a liquid FeO-CaO-SiO2 slag was shown in the research work of Semykina [7]. Fan [8] reported the crystallization behavior of copper smelter slag during molten oxidation.…”

Section: Introductionmentioning

confidence: 93%

“…Although the oxidation of iron-bearing phases in metallurgical slags have been studied [5][6][7][8]13], few reports about the influence of factors on the crystallization of magnetite phases in nickel slag were available. In this work, holding time, temperature, air flow rate, basicity, particle size and magnetic flux were adjusted to study their influence on the crystallization behavior of magnetite phases, attempting to provide a scientific basis for the recovery of iron sources from nickel slags.…”

Section: Introductionmentioning

confidence: 99%

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Crystallization and Beneficiation of Magnetite for Iron Recycling from Nickel Slags by Oxidation-Magnetic Separation

Shen

et al. 2017

Metals

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Abstract:The iron resources in nickel slag were recycled by oxidation and magnetic separation. The effects of holding time, temperature, air flow rate and basicity on the crystallization of magnetite were investigated systematically. Moreover, the influence of particle size and magnetic flux density on the recovery and grade of iron during the magnetic separation was also explored. Results showed that the magnetite particles were significantly influenced by holding time, and the average diameter size reached about 20 µm after holding for 20 min at 1623 K. The holding temperature obviously affected the microstructure of magnetite phases: with the increase in holding temperature, the shapes of the magnetite particles changed from polyhedral form to skeletal particles. As the air flow rate was increased to 170 mL/min, the magnetite developed into tiny spherical particles due to the strong stirring. It was also found that the crystallization of magnetite was slightly effected by basicity. The iron recovery reduced with the decrease of particle size, while the iron grade first increased to a maximal value of 38 µm, and then decreased. As the magnetic flux density increased, the iron recovery initially increased rapidly, reaching a maximal value at 120 mT, while the iron grade remained almost constant. The final iron recovery and grade were 75.99% and 54.08%, respectively, via multi-step magnetic separation instead of single magnetic separation. Iron in concentrate mainly exists in the form of magnetite and magnesium ferrite, and contents of siderophile elements (Ni, Co) in final concentrate were also higher than that of raw slags.

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Section: Influence Factors On the Crystallization Of Magnetitesupporting

confidence: 91%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Crystallization and Beneficiation of Magnetite for Iron Recycling from Nickel Slags by Oxidation-Magnetic Separation

Shen

et al. 2017

Metals

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“…The steel industry produces large volumes of waste slag with huge sensible heat (at extremely high temperature >1500°C) and considerable amount of metals (Fe, Mn, V, Cr, Semykina et al (2010aSemykina et al ( , 2010bSemykina et al ( , 2011b. This promising method may enable efficient selective recovery of transitional metal oxide from steelmaking slags, especially for the CaO-SiO2-FeO(-MnO-V2O3) bearing steelmaking slag.…”

Section: Introductionmentioning

confidence: 99%

Development of a novel process for energy and materials recovery in steelmaking slags

Bhattacharjee

et al. 2017

Mineral Processing and Extractive Metallurgy

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. (2017) Development of a novel process for energy and materials recovery in steelmaking slags. Mineral Processing and Extractive Metallurgy , 126 (1-2). pp. 94-105. Permanent WRAP URL:http://wrap.warwick.ac.uk/83697 Copyright and reuse: The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. Development of a novel process for energy and materials recovery in steelmaking slagsThis work aims at gathering fundamental knowledge for the development of a novel process for energy (H2 gas) and materials (magnetite Fe3O4) recovery in hotsteelmaking slags by reacting molten steelmaking slag with steam.Thermodynamic simulation was carried out to calculate the accumulated amount of produced H2 gas as a function of the volume of H2O-Ar gas introduced and the precipitated phases of the molten slags during controlled cooling. Laboratory experiments of crystallisation behaviours of molten slags during cooling were visualized in situ through a confocal laser scanning microscope (CSLM), and the cooled slags obtained were characterised by using SEM-EDS and XRD. CCT diagrams for different slags were created showing the slag crystallisation/phase transformation at different cooling rates. The recovery ratio of H2 gas and the maximum potential recovery ratio of iron oxide in the oxidised slags were calculated, which concludes that with increasing the slag basicity from 1.0 to 1.5 and 2.0, the recovery ratio of H2 was found to increase from 12.6% to 23.7% and 22.6%, and the maximum potential recovery ratio of iron oxide was found to increase from 18.3% to 34.4% and 32.8% under the investigated conditions.Keywords: steelmaking slag; H2 gas; spinel; CCT diagram; recovery IntroductionThe steel industry produces large volumes of waste slag with huge sensible heat (at extremely high temperature >1500°C) and considerable amount of metals (Fe, Mn, V, Cr, Semykina et al. (2010aSemykina et al. ( , 2010bSemykina et al. ( , 2011b. This promising method may enable efficient selective recovery of transitional metal oxide from steel...

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“…2) The composition of gas-phase in contact with solidified metal, depending on the mold mixture composition, can vary in a wide range in terms of CO, CO 2 Carbon (IV)oxide can be produced and consumed according to reactions (7,8,9).…”

Section: Introductionmentioning

confidence: 99%

Chemical Thermodynamic Processes at Metal-Mold Interface

et al. 2013

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At the contact surface between the liquid metal and the mold wall a number of chemical and thermodynamical reactions were taken. The products of those reactions are spread out on both the sides, i.e., in the solidified metal or into the mold wall. The processes which took place in the casting mold ® here made from sand mix, during the pouring of liquid metal, solidification and cooling down to room temperature, are pretty complex.The thermodynamic reactions at the contact surface of liquid metal/sand mold in the process of castings forming are discussed in this paper. Experiments were performed in molds made by CO 2 sand casting process. As a pouring metal we used steels from an ordinary production program of a steel foundry, exactly it was the steel GS 50CrMo4, assigned by DIN.Some results obtained in our investigations during studying those processes are shown here.

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Confocal Scanning Laser Microscopy Studies of Crystal Growth During Oxidation of a Liquid FeO-CaO-SiO2 Slag

Cited by 38 publications

References 3 publications

Crystallization and Beneficiation of Magnetite for Iron Recycling from Nickel Slags by Oxidation-Magnetic Separation

Crystallization and Beneficiation of Magnetite for Iron Recycling from Nickel Slags by Oxidation-Magnetic Separation

Development of a novel process for energy and materials recovery in steelmaking slags

Chemical Thermodynamic Processes at Metal-Mold Interface

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