Countercurrent Reduction of Iron Ore Particles by Fluidized Rotary Bed with Drum Type Reactors

Abstract

Fine iron ore particles were countercurrently reduced with hydrogen gas at 750°C by fluidized rotary bed in order to pursue the potentiality of the fluidized bed process in direct reduction processes.
As the fluidized rotary bed is established only by balancing centrifugal force applied to the ore particles with gravity, it is independent of gas flow rate. Therefore, countercurrent operation of ore and gas can be easily obtained.
In this experiment, three kinds of reactor (i.e. drum type reactor, conical type reactor, L/D reactor) were used for the purpose of obtainning basic data. Gas utilization coefficient attained with these reactors increases with the increase of stage number or L/D value and exceeds equilibrium value (Fe/FeO) even if in high fractional reduction, which means countercurrent reduction should be established.
Thus, for the purpose of evaluation of this effect, mixing behavior of ore particles was studied by impulse response method in the cold state. Obtained internal age distribution curve has a tendency of shifting from complete mixing flow to plug flow with the increase of the stage number or L/D value, which results coincide with the estimation inferred from the countercurrent reduction test.