US 6,284,017 B1 · Method and facility for producing reduced iron

Abstract

In the method of producing reduced iron according to the invention, fine iron oxides and powdery solid reductants are mixed, compacted into sheet-like compacts, and charged onto the hearth of a reduction furnace for reduction while maintaining the temperature inside the furnace at not less than 1100° C. As the sheet-like compacts can be obtained by compacting mixture of raw material by use of rollers or the like, processing time is much shorter than the case of pelletization or agglomeration. A drying step is unnecessary since feeds are placed no the hearth via a feeder chute or the like. The method is carried out with ease by use of the facility according to the invention. High quality hot metal can be produced by charging reduced iron in hot condition obtained by the method described as above into a shaft furnace or a in-bath smelting furnace for melting at high thermal efficiency.

Claims32

Dependent claims

A method of producing reduced iron from fine iron oxides, comprising the steps of a) through d) as follows:

a) obtaining raw material mixture by mixing fine iron oxides and powdery solid reductants with water or at least one kind of binder, singly or in combination;
b) compacting the raw material mixture into compacted sheet by a double roller;
c) placing the compacted sheet on a horizontally rotatable hearth of a reduction furnace;
and
d) reducing iron oxides by blowing fuel and oxygen containing gas into a reduction furnace, and burning the fuel, combustible volatile constituents issued from the powdery solid reductants and the CO gas generated as a result of reduction of the iron oxides by the agency of the powdery solid reductants, so that a temperature inside the furnace is maintained at not less than 1100° C.

2 more elements

A method of producing hot metal from fine iron oxides, comprising the steps of a) through g) as follows:

a) obtaining raw material mixture by mixing fine iron oxides and powdery solid reductants with water or at least one kind of binder, singly or in combination;
b) compacting the raw material mixture into compacted sheet by a double roller;
c) placing the compacted sheet on the horizontally rotatable hearth of a pre-reduction furnace;
and
d) pre-reducing iron oxides by blowing fuel and oxygen-containing gas into the pre-reduction furnace, and burning the fuel, combustible volatile constituents issued from the powdery solid reductants and the CO gas generated as a result of reduction of the iron oxides by the agency of the powdery solid reductants, so that a temperature inside the furnace is maintained at not less than 1100° C.;
e) discharging the reduced iron obtained through the condition discharged through the discharge step described above, by charging the reduced iron together with carbon material and flux into a shaft furnace from the upper part thereof, having a carbon material bed therein, and tuyeres in the lower part thereof for oxygen containing gas blown in therethrough to combust tuyeres in the lower part thereof for oxygen containing gas blown in therethrough to combust the carbon material disposed in front thereof, generating reducing gas at a high temperature, so that hot metal and molten slag are discharged through a tap hole provided in the lower part of the shaft furnace;
and
g) recovering off-gases generated in the shaft furnace, and recycling a part of the off-gases into the pre-reduction furnace for use as a fuel for pre-reduction.

5 more elements

A method of producing hot metal from fine iron oxides, comprising the steps of a) through g) as follows:

a) obtaining raw material mixture by mixing fine iron oxides and powdery solid reductants with water or at least one kind of binder, singly or in combination;
b) compacting the raw material mixture into compacted sheet by a double roller;
c) placing the compacted sheet on the horizontally rotatable hearth of the pre-reduction furnace;
and
d) reducing iron oxide by blowing fuel and oxygen-containing gas into the pre-reduction furnace, and burning the fuel, combustible volatile constituents issued from the powdery solid reductants and the CO gas generated as a result of reduction of the iron oxides by the agency of the powdery solid reductants, so that a temperature inside the furnace is maintained at not less than 1100° C.;
e) discharging the reduced iron obtained through the pre-reduction step from the pre-reduction furnace at a temperature not less than 500° C.;
f) reducing and melting the reduced iron in a hot condition discharged through the discharge step described above, by charging the reduced iron together with carbon material and flux into a in-bath smelting furnace from the upper part thereof, the in-bath smelting furnace having molten metal bath and molten slag bath therein, and through the bottom of which gas for agitation is blown into the molten metal bath for stirring up the molten metal bath and molten slag bath while oxygen is blown therein to from the upper part thereof, so that hot metal and molten slag are discharged through a tap hole provided in the lower part of the in-bath smelting furnace;
and
g) recovering off-gases generated in the in-bath smelting furnace, and recycling a part of the off-gases into the pre-reduction furnace for use as a fuel for pre-reduction.

6 more elements

Dependencies are inferred from the claim text.

Method and facility for producing reduced iron

Life of this patent

Method and facility for producing reduced iron

Life of this patent

Abstract

Claims32