PURPOSE: To realize a low-cost multi-stage fluidized-bed furnace capable of average improving by increasing the in-furnace resident time of ore with a simple structure.
CONSTITUTION: The space on a dispersing plate of a prereducing furnace 31 is divided into a plurality of sections by partition walls 12, and a preheating section 32 is provided as one of them. An oxygen inlet 33 is provided at the section 32, the part of reducing gas for fluidizing iron ore is burnt, and the temperature of the gas lowered by the charge of the ore is raised. The temperature of a fluidized bet is raised from 600°C to 750°C by next section by preheating, further raised from 800 to 850°C, and discharged in the state that the prereducing rate is improved. The transfer between the sections is conducted via an opening 13 provided at the wall 12.
YAJIMA KENICHI
KISHIMOTO MITSUHARU
