Manganese Distribution Equilibrium between CaO–FetO–SiO2–MnO–P2O5–(Al2O3) Slags and Carbon Saturated Iron

Abstract

In order to find out the optimum thermodynamic conditions for hot metal demanganization and predict the manganese content after demanganization pretreatment, the equilibrium experiments for the measurement of manganese distribution between CaO–FetO–SiO2–MnO–P2O5–(Al2O3) slags with silver were carried out in an iron crucible at 1573–1673 K under pure argon atmosphere. The manganese contents in silver were converted to that in the carbon-saturated iron using the known thermodynamic data. The distribution ratios between slags and carbon-saturated iron were calculated. The results indicate that manganese distribution ratios increase with a decrease in slag basicity, and they increase with an increase in FetO content in the slags at first, then they decrease with an increase in content of FetO. The maximum manganese distribution ratio is 576.6 with the FetO content of 50.30 mass% and the slag basicity of 0.27 at 1623 K, and the correspondent manganese content in the carbon saturated iron is 0.015 mass%. The manganese distribution ratios decrease with an increase in MnO content in the slags. On the other hand, Al2O3 content in the slag has little influence on the manganese distribution ratios. The equilibrium manganese distribution ratios obtained in the present work were summarized as a function of slag compositions and temperature by the multiple regression method.