CN102409124A - Continued ironmaking device based on melting reduction - Google Patents

Abstract

The invention relates to a continued ironmaking device based on melting reduction of iron oxide containing carbon iron oxide balling (blocks). In the invention, the device is a continued ironmaking device based on melting reduction and can carry out continual tapping by pre-reducing furnace burden (3) through continually adding the furnace burden (3), extracting air, preheating, blasting and carrying out downstream roasting, and directly conveying the pre-reduced furnace burden (3) into a smelting-separating furnace (B) for continuous smelting-separation; a preheat area (4), a roasting area (5) and the smelting-separation areas behind the preheat area and the roasting area form a connected hearth; a combustion-supporting burner (8) and a secondary tuyere (7) are arranged also; preferably, the high-temperature coat gas generated in the smelting-separation area is subjected to secondary combustion in a pre-reduced furnace (A) for preheating and roasting the furnace burden (3); then the furnace burden (3) is discharged into the smelting-separation area for the further reduction, carburization and melting to separate the slag and iron; in the preheated area (4), the fuse passes through a bed of material to directly heat the furnace burden (3), and then the fuse enters a heat exchanging device (9) and a fuse process system; and a fan blasts the cool air below the bed into a hearth bottom (2) through the heat exchange device (9). The device has the advantages of short flow, reduced energy consumption, low carbon emission, low production cost, simple equipment, less occupied space, less investment and short building period.

Description

The continuous iron-smelting device of a kind of melting and reducing

One, technical field:

The invention belongs to metallurgical non-blast furnace ironmaking field, relate to carbon containing ferriferous oxide pelletizing (piece) the melting and reducing device of ironmaking continuously.

Two, background technology:

Blast furnace remains the main force of metallurgy industry ironmaking at present.But because blast furnace process is long, capital cost is high, complex equipments, energy consumption are high, envrionment conditions is poor; Coke resource is non-renewable; Under market energy shortage, increasingly competitive situation, people's sight has to turn to exploitation new non-blast furnace ironmaking technology and ironmaking equipment.

Not having burnt low the pollution is the target of non-blast furnace ironmaking novel process.New in the world ironmaking technique of fusion and reduction is divided into two types basically: a kind of be use directly that fine ore and mill coal smelt be called " single stage method " method for melting reduction iron making; Like the AusIron method of Muscovite Romelt, the exploitation of Australian Ausmelt company, the prereduction rate is 0.Another kind method be have a prereduction process be called " two step method " method for melting reduction iron making, representative method such as COREX method, the prereduction degree of metalization reaches 80%～90%.

The difficult point of " single stage method " melting and reducing is that liquid iron oxide compound and carbon reaction are intensive thermo-negative reaction, keep the liquid state of ferriferous oxide, needs very high temperature.Generally the temperature of fusion by metal that melting and reducing generates exceeds about 200 ℃～400 ℃ than liquid iron oxide compound.This technology is preferential fusing red stone in design, rather than reducing iron oxides.Just because of the strong endothermic response feature of this reason and melting and reducing, the metal and the slag of generation solidify easily, and this has brought trouble to production.Also there is refractory consumption rate worn-out end high and with short production cycle in " single stage method " melting and reducing, and a large amount of coal gas of high temperature of generation utilize " bottleneck " that becomes this technological development again.

" two step method " melting and reducing is that ferriferous oxide is carried out prereduction earlier, then the prereduction thing is sent into the molten stove that divides again and carry out the separation of slag iron, so it is to be main reduction reaction with indirect reduction." two step method " melting and reducing or with delivering to the molten stove that divides after the furnace charge after the prereduction cooling again; The coal gas that maybe will melt the generation of branch stove carries out prereduction through furnace charge simply, and process all produces a large amount of heat-energy losses.Therefore " two step method " though the melting and reducing difficulty is less, carbon consumption is higher.Typically the prereduction rate of " two step method " smelting reduction process such as COREX method reaches 90%, and with the blast furnace ratio, it relies on indirect reduction more.Though COREX method large scale investment industrial production, but still need lump ore and few part of coke (about about 20%), coal consumption and oxygen consumption are all higher, reach 1.1t and 500m respectively ³The one-time investment that comprises oxygen generating plant is huge, and production cost is higher than blast furnace.The COREX blast furnace technology that developed has been obtained business success, but has also inherited some shortcomings of blast furnace ironmaking simultaneously, is successful technology, but is not best technique.

The Chinese patent ZL 2,004 1 0023995.X melting reduction iron-smelting method of molten iron " the carbon containing iron agglomerate produce " be one will " single stage method ", " two step method " combine also improved method for melting reduction iron making; Have thermo-efficiency height, save energy, pollution-free, cost is low, and the better products quality is arranged; Production technique is easy; Easy to control, equipment is simple, less investment, characteristics such as production efficiency height.But part still has some deficits in energy utilization.

Three, summary of the invention:

To the problem of above existence, through studying for a long period of time, the present invention improves on patent ZL 2,004 1 0023995.X " carbon containing iron agglomerate is produced the melting reduction iron-smelting method of molten iron " basis; Provide a kind of new melting and reducing continuous iron smelting method, it both had the fireballing characteristics of direct reduction reactor of " single stage method " melting and reducing carbon, had the high characteristics of " two step method " prereduction degree of metalization again; The present invention adopts continuous charging, exhausting preheating, air blast following current roasting; Furnace charge is carried out prereduction; The furnace charge of the high temperature after the prereduction, high degree of metalization is directly sent into the molten stove that divides, molten continuously branch, continuous tapping.The present invention is with the preheating zone on the siege, roast area and be connected thereafter molten zoning design for being communicated with burner hearth; In pre-reducing furnace and the molten joint portion of stove of dividing combustion-supporting burner has been installed; Suitable position at pre-reducing furnace is equipped with overfiren air port, earlier the carbon containing ferriferous oxide is carried out prereduction in pre-reducing furnace, and the preferential coal gas of high temperature that contains a large amount of CO that utilizes molten subregion to produce carries out secondary combustion preheating, roaster mix in pre-reducing furnace; Then the furnace charge with the high temperature after preheating, the roasting, high degree of metalization enters molten subregion; Further reduce-carburizing-fusing at molten subregion, be reduced into iron, and slag iron is separated; At pre-reducing furnace, through the flue gas entering preheating zone of roast area, flue gas passes the bed of material in the preheating zone, and entrained heat is directly passed to furnace charge, gets into heat-exchanger rig and smoke processing system again and carries out waste heat recovery and flue gas ash removal processing.

Upper strata charging status in the end in prereduction of the present invention district and the molten subregion is close, does not have tangible dividing point between two steps.The design that is communicated with burner hearth has solved the coupling of prereduction with whole reduction throughput, does not have the problem of the molten branch ability of COREX technology greater than the prereduction ability, helps comprehensive utilization of energy, helps organization of production, can reduce consumption, saves production cost.

The continuous iron smelting method of a kind of melting and reducing of the present invention; It is characterized in that earlier the carbon containing ferriferous oxide being carried out prereduction in pre-reducing furnace; And the preferential coal gas of high temperature that contains a large amount of CO that utilizes molten subregion to produce carries out secondary combustion in pre-reducing furnace; Release physical heat and chemical energy come preheating, roaster mix, save energy.Then the furnace charge with the high temperature after preheating, the roasting, high degree of metalization enters molten subregion, further reduces-carburizing-fusing at molten subregion, is reduced into iron, and slag iron is separated.

The flow process of the continuous iron smelting method of melting and reducing of the present invention is: after carbonaceous reducing agent (coal, coke and refinery coke etc.) and oxides-containing iron (iron ore, blast-furnace dust, sulfate slag, steel-making ash, electric furnace is grey and mill scale etc.) mix by a certain percentage; Process pelletizing or other shape of carbon containing ferriferous oxide, through delivering on the siege after the super-dry.During device start, similar blast furnace, cupola furnace are the same, moltenly divide stove igniting earlier, and high-temperature flue gas gets into pre-reducing furnace, and furnace charge gets into the roast area roasting reduction then in the preheating of siege preheating zone.The oxygen enrichment hot blast is sent in the bottom of roast area, makes heat zone on the siege to extending below.The top of furnace charge has from molten sectional coal gas of high temperature carries out secondary combustion in pre-reducing furnace, for furnace charge prereduction provides a part of heat energy.The temperature of roast area generally is controlled at 1200 ℃～1300 ℃, and near molten sectional position, temperature should reach about 1350 ℃, makes furnace charge reach desired prereduction degree of metalization fast more than 80%.

High temperature, high degree of metalization furnace charge directly get into molten subregion, carry out slag iron at molten subregion and separate.The fusing point of pure iron is 1539 ℃, and it is necessary reducing fusing point through fusion carbon, so the starting point of furnace charge fusing is to be determined by the residual carbon in the solid state reduction iron particle basically.In the fusing starting point, because by the carburizing of such carbon residue and CO gas, the fusing point of this reduced iron particle reduces, thereby reduced iron melts rapidly.In order to guarantee this quick fusing, also need keep enough carbon in the stove in molten the branch, be beneficial to carburizing, reduce its fusing point.On the one hand for further reduction eventually provides reductive agent, also heat energy is provided at the molten carbon that adds in the stove that divides simultaneously for whole reduction separates with slag iron.Further reduce---carburizing---fusing at molten subregion, accomplish slag iron and separate.

Molten sectional fuel can be lump coal, coal dust, coke powder, also can be solar oil or Sweet natural gas.

Because the present invention will be melted branch stove and pre-reducing furnace and is designed to one and be communicated with burner hearth, molten divide that stove produces contain a large amount of CO, H ₂Coal gas of high temperature Deng gas can directly get into pre-reducing furnace.In pre-reducing furnace and the molten joint portion of stove of dividing combustion-supporting burner has been installed, overfiren air port has been installed, made coal gas carry out secondary combustion, for pre-reducing furnace provides heat energy at the suitable position of pre-reducing furnace.Flue gas through roast area gets into the preheating zone, and flue gas passes the bed of material, and entrained heat is directly passed to furnace charge, gets into smoke processing system again, helps the recovery of fume afterheat.

Behind the flue gas entering preheating zone through roast area among patent ZL 2,004 1 0023995.X " carbon containing iron agglomerate is produced the melting reduction iron-smelting method of molten iron ", flue gas is discharged by the flue that is arranged on the preheating zone mostly.Flue gas mainly is to lean on thermal radiation to the preheating of furnace charge, and the great amount of high-temperature flue gas is discharged by the flue of preheating zone.And flue gas discharge opening is no longer established in preheating zone of the present invention; Flue gas is under the effect of vacuum fan; Be passed down through furnace charge entering smoke processing system and carry out dedusting and heat exchange; Flue gas direct heating furnace charge, the waste heat of flue gas have obtained utilizing better, and the temperature of the charge preheating in the preheating zone has also obtained further raising.

Making full use of of molten branch kiln gas heat is the important measures that solve " bottleneck " of the development of restricting current melting and reducing, also is key character of the present invention.It has improved energy utilization rate greatly, has reduced consumption, has practiced thrift cost, helps applying of melting and reducing technology.

Sulphur in the metallic iron in order to obtain the low metallic iron of sulphur content, can mix CaO (lime or Wingdale etc.), dual alkalinity value (CaO/SiO mainly from iron ore and coal, coke and refinery coke etc. in carbon containing ferriferous oxide raw material ₂Ratio) be about 0.9～1.8, the S content of the metallic iron that obtains at last should meet national respective standard.

The present invention has following several big characteristics:

1. pre-reducing furnace A and the molten stove B that divides are designed to a connection burner hearth, have thoroughly solved the coupling of prereduction with whole reduction throughput.

2. it is short not have coking, no sintering circuit thereby flow process.

3. low the pollution, low-carbon emission can be smelted iron with mill coal without coke.

4. continuous charging, continuous molten the branch and continuous tapping, effectively reduce production costs.

5. the following current roasting can reduce furnace charge and reoxidizes.

6. be communicated with burner hearth, exhausting preheating and blast roasting and can reduce energy consumption significantly.

7. the better products quality is arranged, can reach blast-melted quality.

8. the prereduction degree of metalization is not had strict requirement, the controlling of production process ratio is easier to, at any time start-stop.

9. equipment is very simple, and floor space is few, and one-time investment is few, and the construction period is short.

10. production efficiency is high, and the effective siege floorage of pre-reducing furnace productivity can reach 300Kg/m ²More than the h, the molten stove utilization coefficient that divides is much higher than blast furnace.

Four, description of drawings

Accompanying drawing is the continuous iron-smelting device synoptic diagram of melting and reducing of the present invention.

Five, embodiment:

As shown in the figure, pre-reducing furnace A and the molten stove B that divides are designed to be communicated with burner hearth, and siege 2 can adopt various levels or small inclination moving-bed, like vibrating bed, and chain bed etc.After adding feed bin 1 and will mixing by a certain percentage by carbonaceous reducing agent (coal, coke and refinery coke etc.) and oxides-containing iron (powder iron ore, blast-furnace dust, sulfate slag, steel-making ash, electric furnace is grey and mill scale etc.); Process carbon containing ferriferous oxide pelletizing (piece) furnace charge 3, deliver on the siege 2 through (or directly) after the super-dry.About 100mm～the 300mm of bed thickness on the siege 2, furnace charge 3 move to the molten stove direction of dividing on siege 2.On 4 sieges 2 of preheating zone fire grate is housed; The wind chamber that is communicated with smoke processing system 9 is equipped with in the bottom of preheating zone 4 sieges 2; High-temperature flue gas passes furnace charge 3 bed of materials in the pre-reducing furnace A under the effect of vacuum fan 10; Direct heating furnace charge 3 carries out drying and preheating to furnace charge 3, and then gets into heat-exchanger rig 9 and smoke processing system through wind chamber.Furnace charge 3 is advanced to roast area 5 gradually on siege 2, reduced by high-temperature roasting at this.Roast area 5 extends to the molten stove B that divides always, and the furnace charge 3 after the roasting directly falls into molten the branch in the stove B.On roast area 5 sieges 2 fire grate is housed also, siege 2 bottoms of roast area 5 blast 300 ℃～700 ℃ oxygen enrichment hot blasts through heat-exchanger rig 9 (or other heat-exchange method) preheating by blower fan 11, to realize the downflow system roasting to furnace charge 3.From the molten coal gas of high temperature that divides stove B to come, light a fire again through combustion-supporting burner 8, blast combustion air through secondary combustion blower fan 6, overfiren air port 7 simultaneously, coal gas is fully burnt, in pre-reducing furnace A, discharge entrained physics heat and the chemical heat of flue gas.Preceding half section of temperature in the pre-reducing furnace A, promptly roast area 5 generally is controlled at 1200 ℃～1300 ℃, and at the position near molten branch stove B, temperature should reach about 1350 ℃, makes the furnace charge degree of metalization more than 80%.Second half section (being preheating zone 4) temperature is generally at 800 ℃～1000 ℃ in the pre-reducing furnace A.

Furnace charge 3 directly gets into the molten stove B that divides through pre-reducing furnace A.In order to satisfy the needs of further reduction---carburizing---fusing and desulfurization; Molten subregion is provided with flux storehouse 13, fuel bunker 14 and the molten feeding device 15 that divides on the stove B, and the fuel in the flux in the flux storehouse 13, the fuel bunker 14 adds solid fuel and flux to molten the branch at any time through feeding device 15 in the stove B.

Blower fan 12 blasts air (hot blast of oxygen enrichment >=30%) through the air port and quickens the reduction of furnace charge---carburizing---fusing in molten branch stove B.16,17 is respectively slag notch and iron notch.

Claims (5)

1. one kind is adopted continuous charging, exhausting preheating, air blast following current roasting; Furnace charge (3) is carried out prereduction, the furnace charge (3) of the high temperature after the prereduction, high degree of metalization is directly sent into the molten stove (B) that divides, molten continuously the branch; The continuous iron-smelting device of the melting and reducing of continuous tapping; Preheating zone (4) on the siege (2), roast area (5) and be connected thereafter molten zoning design for being communicated with burner hearth have been installed combustion-supporting burner (8) in pre-reducing furnace (A) and the molten joint portion of stove (B) of dividing, and at the suitable position of pre-reducing furnace (A) overfiren air port (7) are installed; Earlier the carbon containing ferriferous oxide is carried out prereduction in pre-reducing furnace (A); And preferentially utilize the coal gas of high temperature that contains a large amount of CO of molten subregion generation in pre-reducing furnace (A), to carry out secondary combustion preheating, roaster mix (3), then the furnace charge (3) with the high temperature after preheating, the roasting, high degree of metalization enters molten subregion, further reduces-carburizing-fusing at molten subregion; Be reduced into iron, and slag iron is separated; It is characterized in that: at pre-reducing furnace (A), through the flue gas entering preheating zone (4) of roast area (5), (4) flue gas passes the bed of material in the preheating zone, and entrained heat is directly passed to furnace charge (3), gets into heat-exchanger rig (9) and smoke processing system again; The cold wind that blower fan (11) is sent into blasts siege (2) under bed after heat-exchanger rig (9) is warming up to 300 ℃～700 ℃.

2. the continuous iron-smelting device of a kind of melting and reducing according to claim 1; It is characterized in that: the bed thickness 100mm～300mm on the siege (2); The temperature of roast area (5) generally is controlled at 1200 ℃～1300 ℃; Near molten sectional position, temperature should reach about 1350 ℃ at pre-reducing furnace (A), and the furnace charge degree of metalization is more than 80%.

3. the continuous iron-smelting device of a kind of melting and reducing according to claim 1; It is characterized in that: on preheating zone (4) siege (2) fire grate is housed; The extractor fan that is communicated with smoke processing system is equipped with in the bottom of preheating zone (4) siege (2), and flue gas gets into heat-exchanger rig (9) and smoke processing system through extractor fan after passing bed of material direct heating furnace charge (3) again.

4. the continuous iron-smelting device of a kind of melting and reducing according to claim 1 is characterized in that: on roast area (5) siege (2) fire grate is housed also, blasts temperature from siege (2) bottom and be 300 ℃～700 ℃ oxygen enrichment hot blast.

5. the continuous iron-smelting device of a kind of melting and reducing according to claim 1; It is characterized in that: molten subregion is provided with flux storehouse (13), fuel bunker (14) and the molten feeding device (15) that divides on the stove (B), and the fuel in the flux in flux storehouse (13), the fuel bunker (14) adds the molten stove (B) that divides through feeding device (15).