Slag Formation in Large Scale BOF Steelmaking

Abstract

AbstractSlag has both positive and negative effects in large scale BOF Steelmaking. It absorbs sulphur and binds the phosphorus from the steel. However, slag attacks the refractory lining of the vessel, while manganese and iron oxides in the slag lead to yield losses. A careful choice between the conflicting elements associated with slag formation is necessary for the optimization of the steelmaking process.Slag formation in the top blown BOF is described in short. One of the important aspects is the rate of dissolution of lime. CaO, added to the converter as soft burnt lime, is metallurgically active only when dissolved in a liq uid slag.Experimental operation of a top blown BOF with 300-tons heats is described in which slag samples were taken at different moments during the blowing process. Two schemes of lime addition are discussed viz. (I) all the lime is added in the beginning of the blow in one batch and (II) the lime is fed at a constant rate during the first 1/3 of the blowing period.The differenc...