Effect of direct reduced iron on alumina activity in electric arc furnace slags

Abstract

Test trials were conducted in a 70 t ultrahigh power (UHP) electric arc furnace. The proportion of direct reduced iron (DRI) in the charge varied between 40 and 95%. Slag samples were taken at various time intervals and analysed. The analyses were used for estimating the activity of alumina in the slag. The activity was correlated with the basicity, temperature and DRI proportion in the charge. The results of correlation show that the activity is mainly dependent on the basicity of the slag. It is inversely proportional to the basicity and increases as the temperature rises. The activity increases by 3·8×10- 4 for every 10% increase in DRI proportion in the charge.