Investigation on Mechanism of Size and Density Segregations of Burden Particles in the Blast Furnace

摘要

The mechanism of density and size segregations of particles deposited on the slope at blast furnace top was investigated by experiments and the numerical analysis. When the mixture of different size and density particles are charged onto the surface slope, the two main mechanisms - one is size segregation, the other is density segregation - were pointed out to be influential. In the former mechanism, the smaller particles pass through the void of larger particles which behave like a sieve. In the latter, the heavier particles push away the lighter particles during the collision between the particles of different density. Both of the mechanisms act on simultaneously, and determine the radial distribution of deposited particles at the blast furnace top. Making use of these particle segregation properties, the mixed charging of ore with the large size coke particles is efficiently to control the central gas flow in the actual blast furnace. The coke particles are lighter and larger than the ore particles. Therefore, both of two mechanisms affect the separation of the coke and the ore particles during charging. As a result, the large size and lighter coke deposits only central region, and the central gas flow is strengthened and stable operation is performed at actual blast furnaces. The control of central gas flow was achieved by the mixed charging at the blast furnace.