Effect of Hearth Liquid Level on the Productivity of Blast Furnace

Abstract

Cast house is the heart of blast furnace operation. A stable blast furnace operation requires proper control of hot metal and slag drainage from the hearth. Various problems are encountered if the hearth liquid level exceeds above a critical limit that leads to an unstable blast furnace condition. Moreover, operating too often to control liquid level is also not recommended, as operational cost is increased and refractory erosion increases. Therefore, there is a need to understand the reason that prevails in the abnormal hearth liquid level situations. Understanding the effect of increased hearth liquid level on blast furnace process parameters will enable blast furnace operation to take the proactive actions of controlling the blast furnace abnormality. In the present review, an attempt is made to establish a correlational research to understand the effect on hearth liquid level on various casting parameters and blast furnace process conditions. The adverse effect of hearth liquid level build-up on the state of dead man, gas permeability, tuyere life, hearth linings, slag delay and furnace wall heat load is studied. The various casting strategies adopted in blast furnace operation are discussed along with their advantages and disadvantages, and finally, the recommendations are made to operate the liquid level on narrow band.