Effect of Ore/Coke Ratio as a Function of Blast-Furnace Radius on Configuration of Softening and Melting (Cohesion) Zone

Abstract

A comprehensive mathematical model is developed and tested to assess how the ore/coke ratio as a function of radius in the blast furnace affects the shape of the softening and melting (cohesion) zone. The height of the cohesion zone is determined by the temperature difference between the onset and end of melting for the iron ore materials. The cohesion zone is located between the isotherms formed by lines connecting the points corresponding to the onset and end of melting for materials in six vertical ring zones defined within the blast furnace. The location of the isotherms in the furnace space describes the configuration of the cohesion zone, which has a significant effect on the distribution of gas flow and the economic performance of the blast furnace process. A Λ-shaped cohesion zone was found to be better than a W-shaped cohesion zone from the standpoint of ensuring even operation of the furnace and improving the economic performance of the blast furnace process; however, the hearth temperature in each of the vertical ring zones must exceed the temperature for complete fluidization of the pig iron and slag by at least 50 °C.