Manganese Distribution between FeO‐MnO‐SiO2–CaO–MgO‐Al2O3 Slags and Molten Iron

Pretreatment of high manganese hot metal is suggested to produce hot metal suitable for further processing to steel in conventional LD converter and rich manganese slags satisfy the requirements for the production of silicomanganese alloys. Manganese distribution between slag and iron represents the efficiency of manganese oxidation from hot metal. The present study has been done to investigate the effect of temperature, slag basicity and composition of oxidizer mixture on the distribution coefficient of manganese between slag and iron. Ferrous oxide activity was determined in molten synthetic slag mixtures of FeO‐MnO‐SiO2–CaO–MgO‐Al2O3. The investigated slags had chemical compositions similar to either oxidizer mixture or slags expected to result from the treatment of high manganese hot metal. The technique used to measure the ferrous oxide activity in the investigated slag systems was the well established one of gas‐slag‐metal equilibration in which molten slags contained in armco iron crucibles are exposed to a flowing gas mixture with a known oxygen potential until equilibrium has been attained. After equilibration, the final chemical analysis of the slags gave compositions having a particular ferrous oxide activity corresponding to the oxygen potential of the gas mixture. The determined values of ferrous oxide activity were used to calculate the equilibrium distribution of manganese between slag and iron. Higher manganese distribution between slag and iron was found to be obtained by using oxidizer containing high active iron oxide under acidic slag and relatively low temperature of about 1350°C. Bei Roheisen mit hohem Mangan‐Ge‐halt soll durch eine Vorbehandlung Roheisen erzeugt werden, das für die weitere Verarbeitung zu Stahl in einem konventionellen LD‐Konverter geeignet ist. Schlacken mit hohem Mangan‐Gehalt genügen den Anforderungen zur Herstellung von Mangan‐Slicium‐Legierungen. Die Manganverteilung zwischen Schlacke und Eisen zeigt die Wirksamkeit der Oxidation des Mangans aus dem Roheisen. Die vorliegende Arbeit hatte zum Ziel, die Wirkung von Temperatur, Basizität der Schlacke und Zusammensetzung der Oxidationsmittelmischung auf den Verteilungs‐Koeffizienten des Mangans zwischen Schlacke und Eisen zu untersuchen. Die Aktivität von Eisenoxid wurde in geschmolzenen synthetischen Schlackenmischungen aus FeO‐MnO‐SiO2–CaO–MgO‐Al2O3 bestimmt. Die untersuchten Schlacken wiesen eine Zusammensetzung auf, die entweder ähnlich der der Oxidationsmittelm