Oxidizability characterization of slag system on the thermodynamic model of superalloy desulfurization

Abstract

The oxidizability characterization method of slag system has a decisive influence on the accuracy of the desulfurization model. By carrying out the balance experiments of melting system composed of CaF2–CaO–Al2O3–SiO2–TiO2–MgO–FeO slag system and Inconel 718 superalloy, the influence of Al2O3 and FeO on desulfurization distribution ratio at 1,773 K was studied. Based on the ion and molecule coexistence theory in slag, the effects of three oxidizability characterization methods, [Fe]–[O] balance, [Al]–[O] balance, and [Fe]–[Al]–[O] balance, on the accuracy of desulfurization thermodynamic model were studied. The results show that the effect of FeO on desulfurization distribution ratio is more significant than that of Al2O3 when the FeO content in slag is greater than 0.014%. When the FeO content in the slag is less than 0.014%, the effect of Al2O3 on the slag oxidizability will be greater than that of FeO. The calculated value of [Fe]–[Al]–[O] balance model is closer to the experimental-measured value compared to [Fe]–[O] balance model and [Al]–[O] balance model alone at 1,923 K.

Keywords

• ion and molecule coexistence theory
• desulfurization
• [fe]–[al]–[o] balance
• slag–metal balance experiment