On the Permeability Resistance of Pellets Containing MgO in the Softening and Melting Zone of Blast Furnace

Abstract

An investigation has been made of the permeability resistance of iron ore pellets and sinters in the softening and melting zone, which has large influence on the productivity and the fuel ratio in the blast furnace perfbrmance. The results obtained are as follows:
(1) The pressure drop in this zone greatly increases as the FeO-containing slag melts and flows out into the void in the packed bed of pellets of sinters.
(2) MgO addition in the pellets is effective to decrease this pressure drop because, during reduction, MgO makes solid solution with wnstite called magnesio-wnstite with higher melting point.
(3) By X-ray microanalysis and optical microscopy Mg has proved to be concentrated in the magnetite and Ca-ferrite in the MgO added pellets before reduction.