Parameters affecting manganese oxidation in top blown basic oxygen converter

The data obtained from 84 heats carried out in a 90-t top blown basic oxyge n converter were used to study the effects of slag composition and temperat ure on the activity coefficient and activity of manganous oxide in the slag as well as on the manganate capacity and the manganese distribution betwee n slag and metal. In addition, the dependence of manganese activity in the metal on the concentration of maganese and temperature was also investigate d. The present study carried out in wide ranges of temperature, 1350-1690 degr ees C, and slag basicity expressed as (CaO)/(SiO2), 1.4-10.6, clarifies the dependence of MnO activity coefficient mainly on temperature. The activity coefficient of MnO increases by decreasing the temperature. On the other h and, activity of MnO increases by increasing MnO concentration and temperat ure. Both activity coefficient and activity of MnO in the slag slightly inc rease by increasing the slag basicity. At constant temperature, the activit y of Mn in the molten metal varies linearly with Mn concentration and tends also to increase with increasing temperature at constant Mn concentration. The increase in manganese activity by increasing Mn concentration is much steeper at high temperatures. The manganate capacity as well as manganese d istribution ratio decrease with increasing temperature at constant basicity and tend also to slightly decrease with increasing slag basicity at consta nt temperature. Equations describing the parameters affecting activity coef ficient and activity of manganous oxide in the slag, manganese activity in the metal, manganate capacity and manganese distribution ratio have been de rived.