Decarburization of high carbon ferromanganese melts

Abstract

The effect of oxygen/argon mixing ratio in the bottom blowing gas on the decarburization behaviour of high carbon ferromanganese melt was investigated in the temperature range of 1350 – 1550°C. Thermodynamic analysis indicates that high melt temperature and low P CO are essential for an effective decarburization. An empirical equation for the utilization ratio of oxygen for decarburization was derived as functions of the melt temperature and the oxygen/argon mixing ratio in the refining gas. The utilization ratio of oxygen for decarburization sharply increases as the melt temperature increases and the oxygen ratio in blowing gas decreases. In oxygen refining of high carbon ferromanganese melt, it is not desirable to inject oxygen through bottom tuyères in an early stage of refining. When the melt temperature is low, the oxygen predominantly oxidizes the manganese in melt in spite of high carbon contents. The injection of oxygen/argon mixture gas is found to be an effective decarburization technique when the melt temperature is higher than 1500°C.