Coupled thermal analysis and thermodynamic modeling of the oxide systems containing P2O5 and CaF2

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In this proposed 3-year project, in collaboration with one Canadian company (Danieli-Corus) and two South Korean partners (POSCO and RIST), we will investigate the phase equilibria of oxides containing P2O5 and CaF2 in order to better understand their phase diagrams and complex chemical reactions. The two oxide systems investigated in the present study are the CaO-SiO2-FeO-Fe2O3-P2O5 and the CaO-SiO2-Al2O3-Na2O-CaF2-NaF. Experimental data for these systems are still not sufficient and are often quite inconsistent with each other. The proposed project will use a coupled experimental and thermodynamic modeling technique to save time and reduce research cost. Phase equilibrium experiments under controlled gas atmosphere will be performed using various methods such as a classical quenching technique, DTA, DSC and TGA followed by the XRD and EPMA phase analyses. In the same time, a thermodynamic modeling will be performed to provide new experimental directions. In the final stage, the Gibbs energy model parameters for all phases will be simultaneously optimized to reproduce all reliable experimental data. The resultant computational model parameters will be combined with the currently available FACT oxide database to predict the complex phase equilibria and chemical reactions occurring in the industrial steelmaking processes. The industrial partners will also provide valuable in-house experimental data and evaluate the accuracy of the thermodynamic calculations compared with their own experimental data. Feedback from the partners will enhance the accuracy of the thermodynamic modeling. Results of the project will be applied to the optimization of the current processes and new mold flux design in steelmaking. The knowledge of the project will contribute to the quality improvement of advanced high strength steel for automotive applications. At a larger scale, this study will be useful to the general pyrometallurgy, cement, glassmaking and combustion industries as well as to the geological community.