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Evgueni Jak - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic assessment of Slag matte metal equilibria in the cu fe o s si system
    Journal of Phase Equilibria and Diffusion, 2018
    Co-Authors: Denis Shishin, Evgueni Jak, Sergei A Decterov
    Abstract:

    Equilibria among the Slag, matte and metal Phases in the Cu-Fe-O-S-Si system are critically assessed using thermodynamic modeling. The relationships among matte grade, temperature, partial pressure of SO2, Fe/SiO2 in the Slag, and the copper concentration in the Slag are described by the model, as well as the concentrations of other elements in all Phases. A thermodynamic database is created, which can be used for understanding and improving the pyrometallurgical production of copper. An extensive experimental dataset includes the most recent results obtained by the equilibration/quenching/EPMA analysis technique. These data allow to distinguish the physical entrainment of the matte and solid Phases in the Slag from chemical solubility. As a result, it is possible to describe the copper solubility in the Slag with high accuracy and establish the relationship between copper and sulfur in the Slag. The thermodynamic database of the present study is consistent with previously reported thermodynamic evaluations of binary, ternary and quaternary subsystems. The Slag Phase is modeled using the two-sublattice modified quasichemical model in the quadruplet approximation. The matte and metal liquid Phases are modeled as one solution using the single-sublattice modified quasichemical model in the pair approximation.

  • the effect of cao on gas Slag matte tridymite equilibria in fayalite based copper smelting Slags at 1473 k 1200 c and p so 2 0 25 atm
    Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2018
    Co-Authors: Ata Fallahmehrjardi, P C Hayes, Evgueni Jak
    Abstract:

    Fundamental experimental studies have been undertaken to determine the effect of CaO on the equilibria between the gas Phase (CO/CO2/SO2/Ar) and Slag/matte/tridymite Phases in the Cu-Fe-O-S-Si-Ca system at 1473 K (1200 °C) and P(SO2) = 0.25 atm. The experimental methodology developed in the Pyrometallurgy Innovation Centre was used. New experimental data have been obtained for the four-Phase equilibria system for fixed concentrations of CaO (up to 4 wt pct) in the Slag Phase as a function of copper concentration in matte, including the concentrations of dissolved sulfur and copper in Slag, and Fe/SiO2 ratios in Slag at tridymite saturation. The new data provided in the present study are of direct relevance to the pyrometallurgical processing of copper and will be used as an input to optimize the thermodynamic database for the copper-containing multi-component multi-Phase system.

  • experimental investigation of gas Slag matte tridymite equilibria in the cu fe o s si system in controlled atmospheres development of technique
    Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2017
    Co-Authors: Ata Fallahmehrjardi, P C Hayes, Taufiq Hidayat, Evgueni Jak
    Abstract:

    The majority of primary pyrometallurgical copper making processes involve the formation of two immiscible liquid Phases, i.e., matte product and the Slag Phase. There are significant gaps and discrepancies in the Phase equilibria data of the Slag and the matte systems due to issues and difficulties in performing the experiments and Phase analysis. The present study aims to develop an improved experimental methodology for accurate characterisation of gas/Slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system under controlled atmospheres. The experiments involve high-temperature equilibration of synthetic mixtures on silica substrates in CO/CO2/SO2/Ar atmospheres, rapid quenching of samples into water, and direct composition measurement of the equilibrium Phases using Electron Probe X-ray Microanalysis (EPMA). A four-point-test procedure was applied to ensure the achievement of equilibrium, which included the following: (i) investigation of equilibration as a function of time, (ii) assessment of Phase homogeneity, (iii) confirmation of equilibrium by approaching from different starting conditions, and (iv) systematic analysis of the reactions specific to the system. An iterative improved experimental methodology was developed using this four-point-test approach to characterize the complex multi-component, multi-Phase equilibria with high accuracy and precision. The present study is a part of a broader overall research program on the characterisation of the multi-component (Cu-Fe-O-S-Si-Al-Ca-Mg), multi-Phase (gas/Slag/matte/metal/solids) systems with minor elements (Pb, Zn, As, Bi, Sn, Sb, Ag, and Au).

  • investigation of liquidus temperatures and Phase equilibria of copper smelting Slags in the feo fe2o3 sio2 cao mgo al2o3 system at po2 10 8 atm
    Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2010
    Co-Authors: Hector M Henao, P C Hayes, Colin Nexhip, David Georgekennedy, Evgueni Jak
    Abstract:

    Copper concentrates and fluxes can contain variable levels of SiO2, CaO, and MgO in addition to main components Cu, Fe, and S. Metal recovery, Slag tapping, and furnace wall integrity all are dependent on Phase equilibria and other properties of the Phases and are functions of Slag composition and operational temperature. Optimal control of the Slag chemistry in the copper smelting, therefore, is essential for high recovery and productivity; this, in turn, requires detailed knowledge of the Slag Phase equilibria. The present work provides new Phase equilibrium experimental data in the FeO-Fe2O3-SiO2-CaO-MgO-Al2O3 system at oxygen partial pressure of 10−8 atm within the range of temperatures and compositions directly relevant to copper smelting. For the range of conditions relevant to the Kennecott Utah Copper (South Magna, UT) smelting furnace, it was confirmed experimentally that increasing concentrations of MgO or CaO resulted in significant decreases of the tridymite liquidus temperature and in changes in the position of the tridymite liquidus in the direction of higher silica concentration; in contrast, the spinel liquidus temperatures increase significantly with the increase of MgO or CaO. Olivine and clinopyroxene precipitates appeared at high MgO concentrations in the liquid Slag. The liquidus temperature in the spinel primary Phase field was expressed as a linear function of 1/(wt pctFe/wt pctSiO2), wt pctCaO, wt pctMgO, and wt pctAl2O3. The positions of each of the liquidus points (wt pctFe)/(wt pctSiO2) at a fixed temperatures in the tridymite primary Phase field were expressed as linear functions of wt pctCaO, wt pctMgO, and wt pctAl2O3.

  • liquidus temperatures in the cu2o feo fe2o3 cao sio2 system at metallic copper saturation at fixed oxygen partial pressures and in equilibrium with spinel or dicalcium ferrite at 1200 c and 1250 c
    Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2009
    Co-Authors: Stanko Nikolic, P C Hayes, Evgueni Jak
    Abstract:

    Calcium ferrite Slags, which are represented by the “Cu2O”-FeO-Fe2O3-CaO system at copper saturation, have been applied successfully to existing copper-converting processes. Because of the industrial importance of this system, the characterization of the effects of oxygen partial pressure and silica on the Phase equilibria is necessary to improve the control of process parameters, which include fluxing and operating temperatures. In the current study, experimental methods, which use the equilibration/quenching/electron probe X-ray microanalysis (EPMA) techniques with primary Phase substrate support, were subsequently developed to incorporate fixed oxygen partial pressure experiments. Experiments were carried out at 1200 °C and 1250 °C both with and without silica additions; both liquidus and solidus data were reported for the primary Phase field of spinel and dicalcium ferrite between the oxygen partial pressures of 10−5.0 and 10−6.5 atm. The analyzed compositions of the liquid and solid Phases are used to construct the Phase diagram of the pseudoternary “Cu2O”-“Fe2O3”-CaO system in equilibrium with metallic copper at fixed oxygen partial pressures and with additions of silica. The maximum solubility of silica within the liquid Slag Phase, prior to dicalcium silicate precipitation, was measured at specific conditions. Two empirical equations used for the calculation of the copper oxide concentration in calcium ferrite Slag are evaluated with the new experimental data defined in the current study.

Jak E. - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamic optimization of the binary PbO–CaO and ternary PbO–CaO–SiO2 systems
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium data from the recent study for the PbO–CaO and the PbO–CaO–SiO systems (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO-“CuO”-CaO-SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases: liquid, (Ca,Pb)SiO, (Ca,Pb)SiO, (Ca,Pb)SiO (wollastonite and pseudowollastonite), Pb(Ca,Pb)SiO (ganomalite) solutions, SiO (quartz, tridymite, cristobalite), CaSiO (rankinite), CaO (lime), PbSiO (alamosite), PbSiO, PbSiO, PbSiO lead silicates, PbO (massicot), CaPbO, PbCaSiO (barysilite), PbCaSiO (margarosanite) and PbCaSiO compounds. Analysis of available data has shown the lack of data in the two immiscible liquids range over cristobalite, where several new experiments were done to support the model. The modified quasichemical model is used to describe the liquid Slag Phase. From these model parameters, the optimized ternary Phase diagram is back calculated

  • Thermodynamic optimization of the ZnO–FeO–Fe2O3–SiO2 system
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibria experimental data of the present authors for the ZnO–“FeO”–SiO system in air, ZnO–“FeO”–SiO in equilibrium with metallic Fe, and ZnO–“FeO”–SiO–minor CuO at p(O) ~10 … 10 atm (obtained as a part the research on the multicomponent PbO–ZnO–FeO–FeO–CuO–CaO–SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases in the ZnO–FeO–FeO–SiO system for the whole range of compositions, p(O) between ~10 to 1 atm, and temperature range corresponding to liquid Slag existence (1150–1700 °C). The modified quasichemical model is used for the liquid Slag Phase. From these optimized model parameters, the ternary Phase diagrams are back calculated. The model based on the present set of parameters is in a good agreement with previous and new experimental data, and can be used for predictions of the ZnO–FeO–FeO–SiO Phase equilibria over wide ranges of p(O), compositions and temperatures, as well as multicomponent systems

  • Thermodynamic optimization of the binary CaO–ZnO and ternary CaO–ZnO–SiO2 systems
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium data of the present authors for the CaO–ZnO–SiO system (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO-“CuO”-CaO-SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases. The modified quasichemical model is used for the liquid Slag Phase; lime (Ca,Zn)O, zincite (Zn,Ca)O, α- and α′-dicalcium silicate (Ca,Zn)SiO and tricalcium silicate (Ca,Zn)SiO are described within Bragg-Williams formalism; tridymite, cristobalite SiO, wollastonite, pseudowollastonite CaSiO, rankinite CaSiO, willemite ZnSiO, melilite (hardystonite) CaZnSiO and Ca–Zn feldspar CaZnSiO are treated as stoichiometric compounds. From these model parameters, the optimized ternary Phase diagram is back calculated

  • Thermodynamic optimization of the binary PbO-“Cu2O”, “Cu2O”-SiO2 and ternary PbO-“Cu2O”-SiO2 systems
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium data obtained in the recent study by the authors for the binary PbO–“CuO”, “CuO”–SiO and the ternary PbO–“CuO”–SiO systems in equilibrium with metallic Cu or Pb–Cu alloy (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO–“CuO”–CaO–SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases. The modified quasichemical model is used for the liquid Slag Phase. From these model parameters, the optimized ternary Phase diagram is back calculated. Liquidus surface with cristobalite, tridymite and quartz (SiO), two immiscible liquids, cuprite (CuO), lead silicates (PbSiO, PbSiO, PbSiO, PbSiO), massicot (PbO) and copper plumbite CuPbO primary Phase fields has been constructed. Available experimental data are described within uncertainties. Oxygen partial pressures and distribution of lead between Slag and metal have been calculated

  • Experimental study and thermodynamic optimization of the ZnO–FeO–Fe2O3–CaO–SiO2 system
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium experimental data from the present study for the ZnO-“FeO”-CaO-SiO system in air, combined with Phase equilibria and thermodynamic data from the literature on the ZnO-“FeO”-CaO system in air and ZnO-“FeO”-CaO-SiO system in equilibrium with metallic Fe, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases in the ZnO–FeO–FeO–CaO–SiO system. The modified quasichemical model is used for the liquid Slag Phase; spinel (Fe,Zn,Ca) (Fe,Zn,Ca,Va)O, melilite Ca(Fe,Fe,Zn)(Fe,Si)O and olivine (Fe,Zn,Ca)(Fe,Zn,Ca)SiO are described with compound energy formalism; lime and wustite (monoxide) (Ca,Fe,Zn)O, zincite (Zn,Fe,Ca)O, calcium-zinc ferrites CaFeO-“CaZnO” and CaFeO-“ZnFeO”, α- and α′-dicalcium silicate (Ca,Fe,Zn)SiO and tricalcium silicate (Ca,Fe,Zn)SiO and silicoferrite of calcium (SFC) CaFeSiO–CaFeSiO are described within Bragg-Williams formalism; for other Phases, previous assessments have been adopted. The Phase diagrams are back calculated with the optimized model parameters. Present study is a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO-“CuO”-CaO-SiO system

Blanpain Bart - One of the best experts on this subject based on the ideXlab platform.

  • Fundamental study of the rare earths recycling through the pyrotetallurgical route - Pase relations and crystallization behavior of the CaO-SiO₂-Nd₂O₃ system
    'Wiley', 2016
    Co-Authors: Le, Thu Hoai, Blanpain Bart, Malfliet Annelies, Guo Muxing
    Abstract:

    This study aims to investigate Phase relations of the CaO-SiO₂-Nd₂O₃ ternary system for high temperature recycling of Neodymium. The Slag samples were equilibrated at 1500°C and 1600°C for 24h in Ar, and quenched in water. From the Phase analysis of the samples, the isothermal sections were partially constructed and the liquid stability regions were assessed. Based on the identified Phase relations, a solidification process with different cooling paths was studied in-situ using a confocal scanning laser microscope within the interesting Slag Phase regions for recycling. The Phases needed for optimizing recycling can be produced accordingly.status: publishe

  • The wetting behaviour of Cu-based alloys on spinel substrates in a pyrometallurgical context
    Maney Publishing, 2015
    Co-Authors: De Wilde Evelien, Bellemans Inge, Campforts Mieke, Khaliq Abdul, Vanmeensel Kim, Seveno David, Guo Muxing, Rhamdhani M. Akbar, Brooks, Geoff A., Blanpain Bart
    Abstract:

    Metal droplet losses in Slags are an important issue in copper industry. One significant aspect that promotes the entrainment of metal droplets in the Slag is their attachment to spinel solids. In the present study, the wetting behaviour of copper alloys on spinel substrates has been investigated in the presence and absence of a Slag Phase. At first, the attachment was investigated using a synthetic Slag containing spinel particles. Microstructural analysis of quenched Slag reveals the presence of microdroplets sticking onto a surface of the spinel particles. Second, the metal-spinel interaction was investigated using the sessile drop technique. Wetting angle measurements were performed between Cu-Ag alloys and MgAl2O4 substrates. A non-wetting behaviour between the alloys and substrates was observed. The results suggest that the oxygen partial pressure and the amount of Ag in the alloy both influence the wetting behaviour

  • Wetting behaviour of Cu based alloys on spinel substrates in pyrometallurgical context
    Maney, 2015
    Co-Authors: De Wilde Evelien, Bellemans Inge, Campforts Mieke, Khaliq Abdul, Vanmeensel Kim, Seveno David, Guo Muxing, Rhamdhani Akbar, Brooks Geoff, Blanpain Bart
    Abstract:

    Metal droplet losses in Slags are an important issue in copper industry. One significant aspect that promotes the entrainment of metal droplets in the Slag is their attachment to spinel solids. In the present study, the wetting behaviour of copper alloys on spinel substrates has been investigated in the presence and absence of a Slag Phase. At first, the attachment was investigated using a synthetic Slag containing spinel particles. Microstructural analysis of quenched Slag reveals the presence of microdroplets sticking onto a surface of the spinel particles. Second, the metal–spinel interaction was investigated using the sessile drop technique. Wetting angle measurements were performed between Cu–Ag alloys and MgAl2O4 substrates. A non-wetting behaviour between the alloys and substrates was observed. The results suggest that the oxygen partial pressure and the amount of Ag in the alloy both influence the wetting behaviour.status: publishe

  • Wetting behaviour of Cu based alloys on spinel substrates in pyrometallurgical context
    'Maney Publishing', 2015
    Co-Authors: De Wilde Evelien, Bellemans Inge, Campforts Mieke, Khaliq Abdul, Vanmeensel Kim, Seveno David, Guo Muxing, Rhamdhani Akbar, Brooks Geoff, Blanpain Bart
    Abstract:

    Metal droplet losses in Slags are an important issue in copper industry. One significant aspect that promotes the entrainment of metal droplets in the Slag is their attachment to spinel solids. In the present study, the wetting behaviour of copper alloys on spinel substrates has been investigated in the presence and absence of a Slag Phase. At first, the attachment was investigated using a synthetic Slag containing spinel particles. Microstructural analysis of quenched Slag reveals the presence of microdroplets sticking onto a surface of the spinel particles. Second, the metal–spinel interaction was investigated using the sessile drop technique. Wetting angle measurements were performed between Cu–Ag alloys and MgAl2O4 substrates. A non-wetting behaviour between the alloys and substrates was observed. The results suggest that the oxygen partial pressure and the amount of Ag in the alloy both influence the wetting behaviour.peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=ymst20status: publishe

Joo Hyun Park - One of the best experts on this subject based on the ideXlab platform.

  • influence of temperature on reaction mechanism of ilmenite ore smelting for titanium production
    Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2019
    Co-Authors: Hyun Sik Park, Joo Hyun Park
    Abstract:

    The carbothermic smelting reduction process of ilmenite ore at high temperature was investigated by thermodynamic calculations in conjunction with smelting experiments. Based on thermodynamic calculations, conducting the smelting process at a higher temperature was recommended to achieve a larger amount of FeO reduction, i.e., higher Ti-enrichment, as less precipitate and thus large amounts of a liquid Slag were predicted. However, even though the reduction of FeO in ilmenite ore at the initial stage seemed to be faster as the temperature increased, no significant difference in the TiO2 or FeO concentration was observed after the reaction was complete, regardless of the temperature. This was caused by the precipitation of pseudobrookite due to the local depletion of FeO during reaction at higher temperatures, by which further reduction reaction was prohibited. The apparent rate constant increased with increasing temperature and the activation energy of the reduction process was estimated to be 144 kJ/mol, from which it was concluded that the reduction reaction of FeO in ilmenite Slag by carbonaceous reductant was generally controlled through the mass transfer in the Slag Phase. Additionally, the formation of TiC also occurred in the iron bath. At 1923 K (1650 °C), approx. 20 pct more TiC was generated as compared to TiC formation at 1823 K (1550 °C), which also prevented further reduction of Fe at higher temperatures.

  • refractory Slag metal inclusion multiPhase reactions modeling using computational thermodynamics kinetic model for prediction of inclusion evolution in molten steel
    Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2017
    Co-Authors: Jae Hong Shin, Yongsug Chung, Joo Hyun Park
    Abstract:

    The refractory–Slag–metal–inclusion multiPhase reaction model was developed by integrating the refractory–Slag, Slag–metal, and metal–inclusion elementary reactions in order to predict the evolution of inclusions during the secondary refining processes. The mass transfer coefficient in the metal and Slag Phase, and the mass transfer coefficient of MgO in the Slag were employed in the present multiPhase reactions modeling. The “Effective Equilibrium Reaction Zone (EERZ) Model” was basically employed. In this model, the reaction zone volume per unit step for metal and Slag Phase, which is dependent on the ‘effective reaction zone depth’ in each Phase, should be defined. Thus, we evaluated the effective reaction zone depth from the mass transfer coefficient in metal and Slag Phase at 1873 K (1600 °C) for the desulfurization reaction which was measured in the present study. Because the dissolution rate of MgO from the refractory to Slag Phase is one of the key factors affecting the Slag composition, the mass transfer coefficient of MgO in the ladle Slag was also experimentally determined. The calculated results for the variation of the composition of Slag and molten steel as a function of reaction time were in good agreement with the experimental results. The MgAl2O4 spinel inclusion was observed at the early to middle stage of the reaction, whereas the liquid oxide inclusion was mainly observed at the final stage of the refining reaction. The content of CaO sharply increased, and the SiO2 content increased mildly with the increasing reaction time, while the content of Al2O3 in the inclusion drastically decreased. Even though there is slight difference between the calculated and measured results, the refractory–Slag–metal multiPhase reaction model constructed in the present study exhibited a good predictability of the inclusion evolution during ladle refining process.

  • recovery of iron and removal of hazardous elements from waste copper Slag via a novel aluminothermic smelting reduction asr process
    Journal of Cleaner Production, 2016
    Co-Authors: Jung Ho Heo, Yongsug Chung, Joo Hyun Park
    Abstract:

    Abstract A novel aluminothermic smelting reduction (ASR) process was investigated for cleaning waste copper Slag; this process is not only able to recover valuable iron, but also eliminates hazardous elements from the end-of-life Slag product. The effect of adding Al on the reduction of iron oxide and subsequent iron recovery from waste copper Slag at 1773 K was investigated by considering the thermophysical properties of the Slag. The content of FeO and Al2O3 in the molten Slag varied dramatically over a 5-min period, followed by nearly constant values. Because the reaction area and volume could not be determined (due to the explosive reaction characteristics of the ASR process), the apparent rate constant was employed for kinetic analysis. Iron recovery exhibited a maximum value at Al/FeO = 0.53. To determine the iron recovery, a novel triangular material balance diagram, which represents the balance among the reduced iron ingot, the reduced iron droplets dispersed in the Slag Phase, and the residual (unreduced) iron, was proposed. Solid compounds, such as spinel and olivine, were precipitated in the Slag during the ASR process; this was confirmed by both XRD analysis and a thermochemical computation method. Furthermore, the reaction mechanism between iron oxide and Al particles was newly proposed; this was based on systematic experimental observations. Finally, the elimination rate of hazardous elements, such as As, Bi, Pb, and Sb, from end-of-life copper Slag by the ASR process was determined.

  • Effect of CaO Addition on Iron Recovery from Copper Smelting Slags by Solid Carbon
    Metallurgical and Materials Transactions B, 2013
    Co-Authors: Jung Ho Heo, Byung-su Kim, Joo Hyun Park
    Abstract:

    We investigated the effect of flux (lime) addition on the reduction behavior of iron oxide in copper Slag by solid carbon at 1773 K (1500 °C). In particular, we quantified the recovery of iron by performing typical kinetic analysis and considering Slag foaming, which is strongly affected by the thermophysical properties of Slags. The iron oxide in the copper Slag was consistently reduced by solid carbon over time. In the kinetic analysis, we determined mass transfer coefficients with and without considering Slag foaming using a gas holdup factor. The mass transfer of FeO was not significantly changed by CaO addition when Slag foaming was ignored, whereas the mass transfer of FeO when Slag foaming was considered was at a minimum in the 20 mass pct CaO system. Iron recovery, defined as the ratio of the amount of iron clearly transferred to the base metal ingot to the initial amount of iron in the Slag Phase before reduction, was maximal (about 90 pct) in the 20 mass pct CaO system. Various types of solid compounds, including Mg_2SiO_4 and Ca_2SiO_4, were precipitated in Slags during the FeO reduction process, and these compounds strongly affected the reduction kinetics of FeO as well as iron recovery. Iron recovery was the greatest in the 20 mass pct CaO system because no solid compounds formed in this system, resulting in a highly fluid Slag. This fluid Slag allowed iron droplets to fall rapidly with high terminal velocity to the bottom of the crucible. A linear relationship between the mass transfer coefficient of FeO considering Slag foaming and foam stability was obtained, from which we concluded that the mass transfer of FeO in Slag was effectively promoted not only by gas evolution due to reduction reactions but also by foamy Slag containing solid compounds. However, the reduced iron droplets were finely dispersed in foamy and viscous Slags, making actual iron recovery a challenge.

Shevchenko M. - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamic optimization of the binary PbO–CaO and ternary PbO–CaO–SiO2 systems
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium data from the recent study for the PbO–CaO and the PbO–CaO–SiO systems (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO-“CuO”-CaO-SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases: liquid, (Ca,Pb)SiO, (Ca,Pb)SiO, (Ca,Pb)SiO (wollastonite and pseudowollastonite), Pb(Ca,Pb)SiO (ganomalite) solutions, SiO (quartz, tridymite, cristobalite), CaSiO (rankinite), CaO (lime), PbSiO (alamosite), PbSiO, PbSiO, PbSiO lead silicates, PbO (massicot), CaPbO, PbCaSiO (barysilite), PbCaSiO (margarosanite) and PbCaSiO compounds. Analysis of available data has shown the lack of data in the two immiscible liquids range over cristobalite, where several new experiments were done to support the model. The modified quasichemical model is used to describe the liquid Slag Phase. From these model parameters, the optimized ternary Phase diagram is back calculated

  • Thermodynamic optimization of the ZnO–FeO–Fe2O3–SiO2 system
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibria experimental data of the present authors for the ZnO–“FeO”–SiO system in air, ZnO–“FeO”–SiO in equilibrium with metallic Fe, and ZnO–“FeO”–SiO–minor CuO at p(O) ~10 … 10 atm (obtained as a part the research on the multicomponent PbO–ZnO–FeO–FeO–CuO–CaO–SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases in the ZnO–FeO–FeO–SiO system for the whole range of compositions, p(O) between ~10 to 1 atm, and temperature range corresponding to liquid Slag existence (1150–1700 °C). The modified quasichemical model is used for the liquid Slag Phase. From these optimized model parameters, the ternary Phase diagrams are back calculated. The model based on the present set of parameters is in a good agreement with previous and new experimental data, and can be used for predictions of the ZnO–FeO–FeO–SiO Phase equilibria over wide ranges of p(O), compositions and temperatures, as well as multicomponent systems

  • Thermodynamic optimization of the binary CaO–ZnO and ternary CaO–ZnO–SiO2 systems
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium data of the present authors for the CaO–ZnO–SiO system (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO-“CuO”-CaO-SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases. The modified quasichemical model is used for the liquid Slag Phase; lime (Ca,Zn)O, zincite (Zn,Ca)O, α- and α′-dicalcium silicate (Ca,Zn)SiO and tricalcium silicate (Ca,Zn)SiO are described within Bragg-Williams formalism; tridymite, cristobalite SiO, wollastonite, pseudowollastonite CaSiO, rankinite CaSiO, willemite ZnSiO, melilite (hardystonite) CaZnSiO and Ca–Zn feldspar CaZnSiO are treated as stoichiometric compounds. From these model parameters, the optimized ternary Phase diagram is back calculated

  • Thermodynamic optimization of the binary PbO-“Cu2O”, “Cu2O”-SiO2 and ternary PbO-“Cu2O”-SiO2 systems
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium data obtained in the recent study by the authors for the binary PbO–“CuO”, “CuO”–SiO and the ternary PbO–“CuO”–SiO systems in equilibrium with metallic Cu or Pb–Cu alloy (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO–“CuO”–CaO–SiO system), combined with Phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases. The modified quasichemical model is used for the liquid Slag Phase. From these model parameters, the optimized ternary Phase diagram is back calculated. Liquidus surface with cristobalite, tridymite and quartz (SiO), two immiscible liquids, cuprite (CuO), lead silicates (PbSiO, PbSiO, PbSiO, PbSiO), massicot (PbO) and copper plumbite CuPbO primary Phase fields has been constructed. Available experimental data are described within uncertainties. Oxygen partial pressures and distribution of lead between Slag and metal have been calculated

  • Experimental study and thermodynamic optimization of the ZnO–FeO–Fe2O3–CaO–SiO2 system
    'Elsevier BV', 2020
    Co-Authors: Shevchenko M., Jak E.
    Abstract:

    Liquidus Phase equilibrium experimental data from the present study for the ZnO-“FeO”-CaO-SiO system in air, combined with Phase equilibria and thermodynamic data from the literature on the ZnO-“FeO”-CaO system in air and ZnO-“FeO”-CaO-SiO system in equilibrium with metallic Fe, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all Phases in the ZnO–FeO–FeO–CaO–SiO system. The modified quasichemical model is used for the liquid Slag Phase; spinel (Fe,Zn,Ca) (Fe,Zn,Ca,Va)O, melilite Ca(Fe,Fe,Zn)(Fe,Si)O and olivine (Fe,Zn,Ca)(Fe,Zn,Ca)SiO are described with compound energy formalism; lime and wustite (monoxide) (Ca,Fe,Zn)O, zincite (Zn,Fe,Ca)O, calcium-zinc ferrites CaFeO-“CaZnO” and CaFeO-“ZnFeO”, α- and α′-dicalcium silicate (Ca,Fe,Zn)SiO and tricalcium silicate (Ca,Fe,Zn)SiO and silicoferrite of calcium (SFC) CaFeSiO–CaFeSiO are described within Bragg-Williams formalism; for other Phases, previous assessments have been adopted. The Phase diagrams are back calculated with the optimized model parameters. Present study is a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–FeO-“CuO”-CaO-SiO system