2001 Volume 87 Issue 5 Pages 335-341
In order to clarify the influence of gangue and micro pore in agglomerates on the reducibility and permeability in the blast furnace, the high temperature properties under load of the native lump are and the pellet produced in the laboratory were measured by use of the past-presented apparatus with the adiabatic heat control.
The solid phase reduction below 1473K before the pressure drop of ore layer goes abruptly up is controlled by the micro pore volume under 15μm. Gangue plays as a prevention factor to reduction and the influence of CaO/SiO2 is large.
The reduction and permeation under the melt formation over 1473K are controlled by the micro pore volume under 1μm. Gangue is also a prevention factor to reduction and the influence of CaO/SiO2 is the largest and exceeds that of micro pore.
The dropping temperature receives the influence of gangue directly, and the influence of SiO2, CaO/SiO2, Al2O3 and MgO was detected.
The influence of gangue on the reduction and permeation under the melt formation, on the dropping temperature and on the micro pore generation under 1μm can be explained by the melt formation due to the low eutectic temperature on the equilibrium phase diagram.
As for the main two mineral structures in sinter, hematite and calcium ferrite, it is important to produce the sinter having a large amount of hematite that can secure the micro pore volume under 15 μm and the minimum amount of calcium ferrite with low CaO/SiO2 and low Al2O3 that maintains the cold strength and prevents the reduction degradation.