Analysis of Blast Furnace Hearth Sidewall Erosion and Protective Layer Formation

In recent years there has been increasing emphasis on extending blast furnace (BF) campaign life.1,2) Procedures have been pursued and BF campaign lives have been steadily increasing.3,4) Many studies on the relationship between inner hearth condition and BF operating conditions, such as heat load, molten iron flow, the lower boundary level and permeability distribution of deadman in hearth have been carried out by using numerical simulation method.5,6) Considering the complexity and variety of phenomena and reactions occurring in the BF, our current knowledge of the inner condition of the BF is still limited. The inner erosion condition of BF can only be observed by the dissection of the furnace after blow-out. Dissection investigations have shown many features in the erosion of hearth refractory. The skull, a layer of metal iron and slag attached on the inner surface of the hearth lining, provides a barrier between carbon brick and molten materials such as liquid iron or slag. As long as the skull exists, the hearth erosion is limited. However, a key question is how a skull layer formed can be maintained during the BF operation. A number of studies have investigated the hearth erosion of the BF, but the information on the composition and the microstructure of lumped skull lining material are still very limited.7–16) An improved understanding of the skull formation and the wear Analysis of Blast Furnace Hearth Sidewall Erosion and Protective Layer Formation