Equilibria of manganese and sulfur between liquid iron and CaO-SiO2-FetO-MgO-MnO slags saturated with 2CaO · SiO2 and MgO

Abstract

The equilibria of manganese and sulfur between liquid iron and CaO-SiO2-FetO-MgO slags saturated with dicalcium silicate and MgO were studied in the temperature range of 1B23 to 1 923 K. The solubility of MgO decreases with increasing FetO content. The values of (%MnO)/[%Mn] increase with increasing FetO content and its relation was formulated by an empirical equation. The activity of FetO for the present slag system almost stays unchanged with increasing FetO content investigated. The oxygen content of metal in equilibrium with (39.9-49.9mass%)CaO-(11.9-15.2mass%)SiO2-(25.2-35.7mass%)FetO-(6.1-7.0mass%) MgO slags saturated with 2CaO · SiO2 and MgO is expressed by the following equation, log[mass%O]=-5 690/T+0.011 The logarithm of the sulfide capacity for the present slags increases with increasing the theoretical optical basicity and its correlation was formulated. Using the relations obtained in this work and mass balance, the charging amount of Mn ore(MnO) for a final manganese content when adding MnO to BOF was predicted and the desulfurized content affected by the addition of Mn ore was also estimated.