CHALLENGES OF BLAST FURNACE CASTHOUSE: FAILURE ANALYSIS OF MAIN RUNNER REFRACTORY CASTABLE

摘要

The Brazilian Ironmaking scenario has experienced major changes in recent years as a result of the huge competition in the global steel market. In Blast Furnace, the use of economically competitive raw materials has allowed a reduction of production costs of hot metal. At the same time, frequent oscillations in the Blast Furnaces operating conditions has been noticed, which has shown a direct impact on the refractories' performance used in the casthouse. The need to adjust the products to increasingly severe operational conditions has been a major challenge for refractory suppliers in order to guarantee the runner's safety and its availability for operation. This paper presents the results of a post-mortem study carried out with a main runner Al_2O_3-SiC-SiO_2-C refractory castable, which showed a remarkable wear in the metal line. The characterization identified unusual findings in the samples: the presence of significant amount of K_2O dissolved in the slag-metal interface and infiltrated slag which suggests a synergy of wear mechanisms and illustrates the severe conditions to which the main runner's working lining could be subjected in today's Blast Furnace casthouse operation.