ACTIVITY OF SILICA IN THE SLAG OF AN ELECTRIC-ARC FURNACE USING DIRECT REDUCED IRON FOR STEELMAKING

Test charges consisting of DRl and scrap were melted in a 70 t UHP electric are furnace. Slag samples were collected and used to estimate the activity coefficient acid activity of silica in the slag and to investigate the influences of basicity, temperature and optical basicity on both of them. A relationship between the activity coefficient and temperature was obtained which shows that the relative partial molar enthalpy of solution of SiO2 in the slag is 70.0 kJ/mol. A simple linear equation has been obtained for the variation of the activity of silica with its concentration in the slag. Metal samples containing from 0.01 to 0.03wt% of silicon show that the mean activity coefficient of silicon dissolved in the bath is 0.991.