Thermodynamics of Refining in Electric Furnace Steelmaking

Abstract

In general, the input impurity levels in the electric and induction furnace charge is low, so refining does not pose any special problems. But the use of poor quality or unsorted scrap or high phosphorus sponge in the charge can lead to significant increase in the input impurity level. Besides, quite often the desired final impurity level is very low. Composition control in these cases pose a problem particularly because a large refining time leads to a higher power consumption and low productivity. To overcome this difficulty, ladle refining as secondary steelmaking practices are widely used along with the electric steel making. In this lecture refining principles both in electric furnace and ladle furnace will be discussed.Even at steelmaking temperatures, the reactions do not attain equilibrium unless the slag and metal phases are well stirred for a reasonable length of time. In this sense, equilibrium thermodynamics cannot give quantitative idea about the extent of actual refining that can be attained in electric and induction furnace.