Doctoral theses of the School of Chemical Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence in Processing of Materials, M.Sc. Junmo Jeon
Public defence from the Aalto University School of Chemical Engineering, Department of Chemical and Metallurgical Engineering.
Title of the thesis: Experimental studies and thermodynamic modeling of metal-slag-refractory interactions in non-ferrous pyrometallurgical processes
Thesis defender: Junmo Jeon
Opponent: Docent Eetu-Pekka Heikkinen, University of Oulu, Finland
Custos: Prof. Daniel Lindberg, Aalto University School of Chemical Engineering
The subject of this study was the development, evaluation, and application of thermodynamic modeling for metal, slag, and/or refractory materials in non-ferrous pyrometallurgical processes. The purposes of this study were: 1) to suggest or apply the optimized ternary Ni-Co-C alloy system, CaO-MgO-ZnO, and MgO-ZnO-SiO2 slag systems with phase equilibria studies to nonferrous pyrometallurgical operations; 2) to suggest proper refractory materials, among MgO-Cr2O3, MgO-Al2O3, and MgO-C, for nonferrous pyrometallurgical operations with interpretation for corrosion behavior at interfacial reactions of CaO-FeOx-SiO2 slags and MgO-Cr2O3/MgO-Al2O3 refractories using thermodynamic modeling.
This study is considered significantly related to other studies in the pyrometallurgy field, as the thermodynamic modeling work is conducted based on the Gibbs energy minimization. The Gibbs energy minimization can explain the reason why thermochemical reactions and/or equilibria of metal-slag-refractory materials occur during the pyrometallurgical processes
As a result, Ni-Co-C, CaO-MgO-ZnO, and MgO-ZnO-SiO2 systems were optimized. Their optimized phase diagrams, with thermodynamic modeling, fit well with experimental data. For the Ni-Co-C system, optimized values of partial enthalpy of mixing for Ni-C and Co-C systems showed a good agreement with experimental data. For the CaO-MgO-ZnO system, a reasonable eutectic point was newly observed and calculated. For the MgO-ZnO-SiO2 system, a reasonable peritectic point was newly observed and calculated. Meanwhile, the MgO-Cr2O3 refractory showed the best performance against CaO-FeOx-SiO2 slags. The corrosion behavior at interfacial reactions between CaO-FeOx-SiO2 slags and MgO-Cr2O3/MgO-Al2O3 refractories was interpreted using thermodynamic modeling.
The optimized Ni-Co-C system can be effectively applied to further Cu-Ni-Co-Fe-Si-C alloy systems, while the optimized CaO-MgO-ZnO and MgO-ZnO-SiO2 systems can be further applied to CaO-MgO-ZnO-CuOx-FeOx-Al2O3-SiO2-S slag systems. The eutectic point and peritectic point information can be applied to deduce optimal temperatures and compositions for the slag in the pyrometallurgy processes. The interpretation of corrosion behavior using thermodynamic modeling can help select suitable refractory materials for the processes.
In conclusion, the thermodynamic modeling can be applied to predict and interpret metal-slag-refractory interactions in non-ferrous pyrometallurgy processes.
Keywords: Thermodynamic modeling, phase equilibria studies, corrosion behavior, metal, slag, and refractory
Thesis available for public display 10 days prior to the defence at .
Contact information:
junmo.jeon@aalto.fi
Doctoral theses of the School of Chemical Engineering
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