Effect of High-Phosphorous Iron Ore Distribution in Quasi-Particle on Melt Fluidity and Sinter Bed Permeability

The effect of high P Brockman ore on the melt fluidity was investigated to make clear the mechanism for the deterioration of permeability 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 increased during sintering by the suppression of pore growth and sinter productivity decreased. To improve productivity using high P Brockman ore, HE has developed an advanced granulation process characterized by segregating high P Brockman ore to the center of quasi-particle, which was coated by dense hematite ore, limestone and coke breeze. 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, enhanced the permeability in the sintering 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.