Method of iron making used coal briquettes in smelting reduction process

摘要

PURPOSE: A method for manufacturing molten pig iron by directly charging coal briquettes formed into uniform lump grain size from pulverized coal into melter gasifier in the smelting reduction process is provided. CONSTITUTION: In a method for manufacturing molten pig iron using coal and reduced iron, the method comprises a step of discharging reduced iron by reducing iron ore in a reduction furnace(2) using reducing gas; and a step of manufacturing molten pig iron using the supplied reduced iron and coal in a melter gasifier(1) and supplying reducing gas generated into the reduction furnace, wherein coal briquettes having a grain size of 8 to 50 mm formed of pulverized coal instead of 10 to 100 wt.% of coal are supplied into the melter gasifier, the coal briquettes have a grain size of 30 to 50 mm, wherein temperature of dome above char bed of the coal and the coal briquettes inside the melter gasifier is 900 to 1,100 deg.C, wherein the coal and the coal briquettes comprise 20 to 45 wt.% of volatile compounds, 20 wt.% or less of ash content and 35 to 80 wt.% of fixed carbon on the dry basis, wherein the coal briquettes comprise 5 to 15 weight parts of one or more of binders per 100 weight part of pulverized coal, the binder being selected from organic binders including asphalt, pitch, molasses, starch, bitumen, coal tar, lignin, paraffin, polymer resin, rosin, pulp and emulsion, and inorganic binders including bentonite, clay, silica, dolomite, quicklime, slaked lime, cement and slag, and wherein molten pig iron obtained in the melter gasifier has a temperature of 1,450 to 1,550 deg.C and contains 1.0 wt.% or less of Si.