Liquid steel containing oxygen (N(o)=3103) is deoxidised with Mn an 1600C. a) Show that there is no slag before the Mn is added, and then calculate the value of N(Mn) required to just produce a slag. FeO and MnO form ideal solid and liquid solutions in all ranges of composition. b) Starting from the relationship: ln[a(MO)aMO]=RT.TfMOHfMO(TfMOT) Calculate the mole fractions of (MnO),MnO>,
and (FeO) in equilibrium at 1500C and 1600C, assuming that HfMO does not change with T, and construct the FeO-MnO phase diagram. c) The slag in equilibrium with the metal (Fe,Mn,O) consists of two phases (liquid \& solid), the compositions of which were determined in (b). What conclusion can be drawn from the analysis of the variance of the system? d) Find the mole fractions of manganese and oxygen in the liquid metal in equilibrium with the slag at 1600C. Assume that the manganese forms an ideal solution in Fe, and the presence of oxygen does not influence its activity. The interaction parameters 0,Mno and Mn0 are assumed to be nil. 21[O2](0)Fe G0=27930+6.08T Calories The infinity dilute solution expressed in terms of atom fraction has been chosen as the standard state for (0)Fe : (Mn)+21[O2]MnO(Fe)+21[O2]FeOMnO(MnO)FeO(FeO)G0=95400+19.62TG0=59830+11.94TGf=107005.2TGf=73004.56TCaloriesCaloriesCaloriesCalories Calories Calories Liquid steel containing oxygen (N(o)=3103) is deoxidised with Mn an 1600C. a) Show that there is no slag before the Mn is added, and then calculate the value of N(Mn) required to just produce a slag. FeO and MnO form ideal solid and liquid solutions in all ranges of composition. b) Starting from the relationship: ln[a(MO)aMO]=RT.TfMOHfMO(TfMOT) Calculate the mole fractions of (MnO),MnO>, and (FeO) in equilibrium at 1500C and 1600C, assuming that HfMO does not change with T, and construct the FeO-MnO phase diagram. c) The slag in equilibrium with the metal (Fe,Mn,O) consists of two phases (liquid \& solid), the compositions of which were determined in (b). What conclusion can be drawn from the analysis of the variance of the system? d) Find the mole fractions of manganese and oxygen in the liquid metal in equilibrium with the slag at 1600C. Assume that the manganese forms an ideal solution in Fe, and the presence of oxygen does not influence its activity. The interaction parameters 0,Mno and Mn0 are assumed to be nil. 21[O2](0)Fe G0=27930+6.08T Calories The infinity dilute solution expressed in terms of atom fraction has been chosen as the standard state for (0)Fe : (Mn)+21[O2]MnO(Fe)+21[O2]FeOMnO(MnO)FeO(FeO)G0=95400+19.62TG0=59830+11.94TGf=107005.2TGf=73004.56TCaloriesCaloriesCaloriesCalories Calories Calories
