TWO STEP TWIN-SINGLE FLUIDIZED BED TYPE PRE-REDUCTION APPARATUS FOR PRE-REDUCING FINE IRON ORE, AND METHOD THEREFOR

摘要

A two step twin-single fluidized bed type reduction apparatus for fine ironore, and a method therefor, are disclosed. The fluidizing of the fine iron oreis stabilized so as to improve the reduction degree and the gas utilizationrate, and so as to minimize the elutriation loss of the iron ore. Theapparatus includes a first fluidized bed furnace (110) for carrying out afirst pre-reduction on only coarse/intermediate iron ore particles among fineiron ores of a wide particle size distribution by a bubbling/turbulentfluidization after their charge from a charging hopper (100), while makingfine iron ore particles fly away. A second fluidized bed furnace (120) carriesout a first pre-reduction on the fine iron ore particles flown from the firstfluidized bed furnace (110) by a bubbling fluidization, and a third fluidizedbed furnace (130) carries out a second pre-reduction on the iron oresdischarged from the first (110) and second (120) fluidized bed furnaces aftertheir first pre-reduction. A first cyclone (124) captures extremely fine ironore particles from an off-gas discharged from the second fluidized bed furnace(120) to circulate them back to the second fluidized bed furnace (120). Asecond cyclone (134) captures extremely fine iron ore particles from an off-gas discharged from the third fluidized bed furnace (130) to circulate themback to the third fluidized bed furnace (130). A gas reforming system (140)reforms a part of the off-gas of the first cyclone (124) to circulate thereformed gas to the first (110) and second (120) fluidized bed furnaces.