THERMODYNAMICS OF MANGANESE OXIDE IN CaO-SIO_2-MgOSAT.-Cr_2O_3-MnO SLAGS FOR THE PRODUCTION OF HIGH MN STAINLESS STEEL

摘要

The manganese equilibria between a manganese rich stainless steelmaking slag (CaO-SiO_2- MgO_(sat.)-MnO-Cr_2O_3) and Fe-Cr-Mn stainless steel were investigated in a temperature range from 1823 to 1873 K under Ar atmosphere. The partition ratios of manganese between the molten slag and the liquid steel were determined as a function of slag composition and temperature. The thermodynamics of MnO in the slag were studied by combining experimental results and thermodynamics theory. It was found that, as basicity increases, the manganese partition ratio, L_(Mn_ = (wt % Mn)_(slag) /[wt % Mn]_(steel), decreases. The elevated basicity leads to a high MnO activity coefficient. The influence of MnO contents on the activity coefficients was also considered. It can be concluded that in order to maximize Mn recovery during high Mn stainless steel production, a basic slag with a high MnO activity coefficient must be employed whereas high temperatures should be avoided.