Title of Publication Edited by TMS (The Minerals, Metals & Materials Society), Year DESULFURIZATION IN THE LADLE FURNACE USING INDUSTRIAL SLAGS Ahmet Geveci 1 , Ender Keskinkilic 2 , Yavuz Ali Topkaya 1 , 1 Middle East Technical University, Department of Metallurgical and Materials Engineering, Ankara 06531, Turkey 2 Erdemir-Iron and Steel Works Co., Kdz. Eregli 67330, Zonguldak, Turkey Keywords: Steelmaking, Desulfurization, Industrial Slags Abstract Generally accepted formula related to sulfur slag-metal distribution ratio is given by the following equation: O S S O a 1 f a K S % ) S (% 2 2 ⋅ ⋅ γ ⋅ = − − According to the above equation it can be deduced that sulfur distribution between slag and metal is governed mainly by metal composition ( S f term), slag composition (slag basicity and in turn sulfide capacity), oxygen potential of the system ( O a term) and temperature (related to equilibrium constant, K). In this study, the results of ladle furnace operations conducted in Erdemir-Iron and Steel Works Co. (Turkey) in relation to sulfur removal, have been given. Typical ladle furnace slag analyses of 4937K quality steel have been presented. Activity coefficient of Fe t O, O Fe t γ , have been calculated with the relation obtained from the literature. Activity calculations have been performed with the program written in Mathcad. The changes in activity of Fe t O in the slag phase, O Fe t a , have also been studied in relation to the sulfur removal: The relation between % Decrease O Fe t a and %DeS (measured) have been investigated for 4937K runs and some other types of steel produced in the Erdemir Plant. Related to ladle operations %desulfurization defined as 100 * ] % / ) % [(% initial final initial S S S − values have been presented for different steel qualities. Introduction Steel designated by 4937K is a chassis steel type containing sulfur of 50 ppm maximum. Chemical composition of 4937K is shown in Table I. While tapping this steel from the 120- ton converter in Erdemir Plant in Turkey, typical alloy additions are ferromanganese (both low and high carbon), coke and ferroniobium; deoxidation is accomplished with the addition of aluminum. Lime is also added to obtain a synthetic slag on top of the liquid steel where lime combines with the common deoxidation product, Al 2 O 3 .