Attack of Magnestic Refractories by Steelmaking Slags

Abstract

<p>Experimental investigations of the attack of carbon-free and carbon-bearing magnesite refractories by synthetic steelmaking slags at 1600°C and relevant theoretical analysis are documented in this thesis.</p> <p>The attack of carbon-free magnesite brick by steelmaking slags was studied by immersing cylindrical specimens in molten slag contained in a noble metal crucible. The major variable of study was the composition of the slag, i.e., the alumina and magnesia contents and the lime-silica ratio.</p> <p>The reacted samples are examined macroscopically in terms of elongation, slag climb and penetration. Microscopic examination by petrographic techniques and microprobe analysis further illustrate the macroscopic observations associated with the chemical reactions taking place between the refractories and the penetrating slag.</p> <p>The role of carbon in extending the lining life of BOF carbon-bearing refractories is the main objective of this research. Test crucibles were reacted with slags. The reacted samples were microscopically studied. The formation and destruction of a dense MgO layer in reacted specimens was studied. Theoretical analysis of the formation of the dense MgO layer was undertaken based on the assumption, that the formation of MgO is the resul t of a gaseous reac.tion between magnesium vapor and carbon dibxide.</p> <p>This work has been carried out under conditions relevant to refractory problems involved in a few major steelmaking vessels. The results obtained here have shed light on the kinetics and mechanism of the attack of magnesite refractories by steelmaking slags.</p>