Post-mortem Analysis of Magnesia-Carbon Refractories from Steel Ladle Furnace Slag Lining

Abstract

Refractory corrosion by slag is among the major causes of refractory deterioration and the subsequent maintenance shutdowns, resulting in downtime and loss of product. In the context of sustainability, the relatively short service life of refractories remains one of the challenges to the steelmaking industry yet to be solved. The initial conditions and process parameters; e.g., slag composition, additives, and bath stirring affect the kinetics and thermodynamics of chemical reactions; i.e., the carbon oxidation and MgO dissolution involved in the refractory-slag system, leading to the eventual loss of refractory lining. To better understand the chemical reactions taking place at the refractory/slag interface, post-mortem samples were microstructurally characterized using scanning electron microscopy coupled with energy-dispersive spectroscopy. Thermodynamic assessments of the system were also performed using FactSage™ v8.2 software and databases to identify the extent of chemical reactions. The obtained results indicated that refractory corrosion is mainly controlled by simultaneous refractory-slag chemical reactions and the mass transport of slag in the porous body of refractory, the details of which are discussed in the present work.