"The use of steelmaking slag as protection for oxidation of MgO-C refractories"

M.N. MOLINÉ; S.E. GASS; P.G. GALLIANO; A.G. TOMBA MARTÍNEZ; D. GUTIERREZ-CAMPOS

Congreso; Pan American Ceramics Congress PACC-FMAs 2022; 2022

MgO-C is one of the most important refractories for steelmaking ladles. Carbon is a keycomponent which allows the refractory to have high resistance to thermal shock and toslag attack. However, C oxidizes in air; this risk is currently found during the preheating of the ladle (at the beginning and between production cycles).During the operation, the liquid steel is evacuated through ladle bottom leaving a slaglayer adhered to the working lining which serves as protection against oxidation ofrefractories’ carbon. Nevertheless, this layer could suffer degradation by ambienthumidity which affects its role as an oxygen diffusion barrier.This work analyzes how the refractory composition (graphite content, type of binder)and the slag degradation affect the oxidation resistance of MgO-C materials. For testing,a slag layer was generated over one of the plane surface of the refractory cylinder(25x25 mm2) by treatment at 1400°C (graphite bed). Only this face was exposed to air(unidirectional test) at 1000°C (2 h). Variations in weight, depth of decarburized layerand graphite content were used as oxidation indicators. To evaluate the effect of slagweathering, tests were carried out after 2 and 10 weeks from the sample conditioning.