Abstract
For stable operation of continuous fluidized bed reduction of iron ore at high temperature and pressure, fluidizing conditions of iron ore particles of a wide size distribution were investigated using a fluidized bed model at room temperature.
At a certain fluidizing velocity it was possible to maintain these iron ore particles of the wide size range at good fluidization, in which the particle size distribution in bed was almost uniform during the continuous operation and the dust from the bed was a little in the amount. On the basis of this suitable fluidizing velocity obtained from the experiment of a cold model, fluidizing velocities corresponding to the change of factors such as temperature, gas composition, and reduction degree of iron ore were calculated.
The controlling method of the flow rate of reducing gas and gas pressure in the reactor in a continuous operation from the start up at room temperature to the steady state at high temperature was devised.
According to this controlling method, the continuous operation of a pilot plant using nitrogen and hydrogen as fluidizing gas was performed at high temperature and pressure.
