Formation Process of Brittle Layer in Carbon Brick and Kinetic Analysis of Dendritic Penetration

Abstract

In order to explore the formation process of brittle layer, the dissection investigation of actual BF was analyzed, the penetration experiments were carried out, the cause of brittle layer formation in carbon brick was summarized. The mechanism of dendritic penetration of molten iron was clarified, the kinetic model of penetration was established combined with the penetration mechanism. The results show that: The brittle layer is observed on the hot face of carbon brick, there are a lot of striated gaps in the brittle layer near the hot face. The penetration depth of molten iron increases with the increase of temperature and penetration time, the penetration velocity is relatively high at the beginning, then gradually decreases. The dendritic penetration of molten iron is a key common problem in carbon brick, it is easier to form at the junction of two phases in carbon brick. There are three paths for each branch of dendritic penetration, the penetration of the third path is extremely destructive to carbon brick owing to the elongation of penetration in this path is relatively large. The essence of the meniscus is the confrontation between the cohesion of molten iron itself and the adhesion between molten iron and carbon brick. The model calculation indicates that the adhesion force is relatively small, the key to prevent the penetration is to control the adhesion force between molten iron and carbon brick. The maximum penetration depth of molten iron can be evaluated through the penetration model.