Fluidization and Degradation Characteristics of Iron Ore Fines in Prereduction Fluidized Bed

The integrated test plant, consisting of a prereduction fluidized bed and in-bath smelting reduction furnace characterized by high post combustion, was installed at NKK Fukuyama Works, and the operation was started in 1988. The prereduction fluidized bed used iron ore fines as feed, and the fluidizing conditions and pressure fluctuation characteristics to keep the stable fluidization were clarified by the operation of the integrated test plant. The classification behavior of fines was analyzed by the measurement of elutriation rate constant. Then, the degradation phenomena of iron ore fines were observed during the preheating and prereduction of iron ore fines in the fluidized bed, and it was quantitatively analyzed by the application of Rittinger's law for size reduction. The model including classification and degradation behavior was constructed so as to estimate the operating condition. These results were considered to be useful in the scale-up of the prereduction fluidized bed.