Abstract

Alumina-Spinel fired refractory brick for steel ladle metal zone lining is one of the recent innovations over last decade. The purpose of such innovation was primarily to cater the growing need of advanced metallurgy for ultralow carbon and automobile grade of steels to reduce Carbon pick-up from refractory body to liquid steel. Even as alternative to other C-free refractories, the newly developed alumina-spinel fired brick is another superior generation fired refractory for achieving high performance in highly corrosive metallurgical environment (such as C/S=1.5, 5% CaF2, 2% MnO2). Such Alumina Spinel brick is manufactured by using proper granulometry of high purity synthetic alumina aggregate (Tabular alumina or white fused alumina or mixed), Mag-Al spinel in finer fractions (Al-rich or Mg-rich) and calcined alumina in matrix. The present work describes the effect of these raw materials and their granulometry on product properties such as density, porosity, shrinkage, cold and hot strengths as well as on the properties such as abrasion, slag corrosion, thermal spalling which are of prime focus of end users for evaluating refractories for predicting higher performances. SEM studies and pore size distributions are analyzed to understand the roles of raw materials on properties. It is seen in industrial applications that refractory lining life has increased significantly with Alumina-Spinel lining compared to previously used MgO-C lining due to superior resistances to abrasion, corrosion and spalling. Although the cost of refractory lining has increased compared to traditional MgO-C linings, however the overall cost of refractory per ton of liquid steel for the steel plant has reduced due to higher lining life in metal zone. The present paper describes the effectiveness of this newly developed fired alumina-spinel refractory in terms of refractory manufacturing (formulations and property evaluations) as well as steel production (application and performance).