Thermodynamic modeling of P2O5 containing oxide system for De-P process in steelmaking: Preliminary thermodynamic modeling results

摘要

The CaO-FeO-Fe2O3-MgO-SiO2-P2O5 oxide system is a basic oxide system for the Basic Oxygen Furnace (BOF) process as well as the hot metal de-phosphorization process. Great amount of investigations on this oxide system are being carried out, particularly in Japan, to find out an advanced process route for P removal from molten iron. In the case of the BOF process, the utilization of a large liquid miscibility gap in the CaO-FeO-Fe2O3-P2O5 system is a new interesting route for the de-phosphorization of molten iron. As the Ca2SiO4 phase in the oxide system can dissolve a considerable amount of P2O5 under the steelmaking condition, it can enhance the de-phosphorization of molten iron during the hot metal pretreatment process. Since Fe has two valence states, Fe2+ and Fe3+, the phase equilibrium in the oxide system can vary strongly with oxygen partial pressures, which induces a difficulty in the phase diagram measurement.