Effect of high-phosphorous iron ore distribution in quasi-particle on melt fluidity and sinter bed permeability during sintering

Abstract

The effect of high P Brockman ore on the melt fluidity was investigated to make clear the mechanism for the deterioration of permeability of sinter bed during sintering. Blending high-P ore, characterized by the high porosity and fine size distribution, decreased melt fluidity by the absorption of melt into porous high P Brockman ore. As a result, the pressure drop of sinter bed increased during sintering by the suppression of pore growth, and the sinter productivity decreased. To improve the sinter productivity using high-P Brockman ore, JFE Steel has developed an advanced granulation process characterized by segregating high-P Brockman ore at the center of quasi-particle, which was coated by coke breeze and limestone. It is important to select the suitable coating thickness of dense hematite ore around porous iron ore for preventing from the melt absorption into iron ore. This process controls the excess melting reaction between iron ore and limestone, owing to the segregation of high-P ore within the quasi-particles. The commercial plant trials showed that the desirable melt fluidity, resulting from the segregation of high-P ore in a quasi-particle, enhanced the permeability of sinter bed at Fukuyama No. 4 Sinter Plant of JFE Steel. The application of new granulation process remarkably improved both the productivity and reducibility of sinter products, in spite of the recent inferior ore conditions. © 2009 ISIJ.