CN1017628B - Method for smelting molten iron directly from powdered coal and iron ore - Google Patents

Method for smelting molten iron directly from powdered coal and iron ore

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Publication number
CN1017628B
CN1017628B CN 88104282 CN88104282A CN1017628B CN 1017628 B CN1017628 B CN 1017628B CN 88104282 CN88104282 CN 88104282 CN 88104282 A CN88104282 A CN 88104282A CN 1017628 B CN1017628 B CN 1017628B
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China
Prior art keywords
coal
iron
forehearth
furnace
stove
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Expired
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CN 88104282
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Chinese (zh)
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CN1039620A (en
Inventor
周渝生
李文采
杜挺
邓开文
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Central Iron and Steel Research Institute
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Central Iron and Steel Research Institute
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Application filed by Central Iron and Steel Research Institute filed Critical Central Iron and Steel Research Institute
Priority to CN 88104282 priority Critical patent/CN1017628B/en
Publication of CN1039620A publication Critical patent/CN1039620A/en
Publication of CN1017628B publication Critical patent/CN1017628B/en
Expired legal-status Critical Current

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Abstract

The present invention relates to a method for directly smelting iron melt by using coal dust and iron ore powder. The method mainly adopts a horizontal or vertical forehearth, a vertical furnace type back furnace, a back furnace bottom trolley connected with the front furnace and the back furnace, a preheater, a heat exchanger, etc. A coal-bearing pellet is a raw material and comprises the iron ore powder, the coal dust, a binding agent and a solvent, and the pellet is preheated by the preheater, and enters the back furnace for prereduction; subsequently, the pellet is further reduced and melted in the trolley of the back furnace, and is overheated and finally reduced in the front furnace, and furnace slag and the iron melt are separated. The method has the advantages of small investment, high productivity, wide raw material adaptability and low cost, and is suitable for medium and small-sized iron making industries.

Description

Method for smelting molten iron directly from powdered coal and iron ore
The invention belongs to the smelting of iron.
Without coke, directly the method with non-coking coal production molten iron is the problem that at present domestic and international steel industry is competitively studied.Need adopt the high-quality reducing gas in the prior art, and with reducing gas pre-reduced iron ore on another shaft furnace that separates or fluidized-bed, or use a part of coke or moulded coal, maybe must use a large amount of pure oxygens or electric power to smelt iron its complex process, cost height.
In Chinese patent application, CN85100843A and CN85101937A provide similar iron smelting method.Their main drawback is: preceding a kind of iron smelting method is not completely free of the dependence of STRENGTH ON COKE or moulded coal as yet; What then a kind of method obtained is granulated iron, rather than molten iron, when producing foundry goods or making steelmaking feed with this granulated iron, also will consume more electric energy or fuel, makes it fusing.
U.S. Pat 3953196 has been stated a kind of direct reducing process of metal oxide.This technology uses the pelletizing that contains 5~30% carbonaceous materials to add shaft kiln directly reduced.This shaft furnace top is the preheating zone, and the middle part is the reduction zone, and the bottom is the melting area of an energy controlled atmosphere.In shaft furnace, be heated with the reductive pelletizing and generate slag, iron in the melting area, and emit outside the stove.When the flame heat supply of fuel combustion, in order to prevent that the iron in the reducting pellet from being reoxidized, partition wall of this patent employing is stared at reactor furnace and is divided into final heating zone (oxidation zone) and controlled atmosphere district (reduction zone).For this reason, fuel consumption is multiplied, and will in same reactor, realizes oxidation (fuel perfect combustion) and reducing atmosphere simultaneously, in theory and practice, all be difficult to realize.
The object of the present invention is to provide a kind of is raw material with powdered iron ore or iron scale, iron filings, is fuel and reductive agent with the non-coking coal, directly the method and the device thereof of smelting molten iron.
The present invention adopts the cold bonded coal-containing iron ore pellets to make iron-smelting raw material, is fuel and the direct smelting molten iron of reductive agent with the non-coking coal powder.
(weight %) is as follows for the chemical constitution of cold bonded coal-containing iron ore pellets: powdered iron ore (or iron scale, iron filings) 60~70%, coal dust 20~30%, binding agent 5~10%, flux 2~5%.The coal dust metabituminous coal accounts for 15~20%, and all the other are hard coal or coke powder or wood charcoal powder.Binding agent be in cement, spent pulp liquors, lime, water glass, bentonite or the sodium humate etc. any two or two or more.Flux is lime powder or limestone powder, and fluorite etc.
The cold bonded coal-containing iron ore pellets can be made ball, also available punching block or pair roller pressure ball with the garden dish.Green pellets can be gone into stove and be smelted after cryodrying or seasoning.
By the pelletizing smelting molten iron is to carry out in the coal dust iron-smelting furnace.This stove is made up of forehearth and back stove etc.Part coal dust sprays into the forehearth burning by primary air nozzle heat is provided, and is used for reduction and fusing pelletizing; Simultaneously, the high temperature low-quality reducing gas of generation enters the back stove from quirk, and contains coal iron ore pellets countercurrent flow, realizes preheating prereduction, and subsequently, pellets will enters overheated, the reduction eventually of forehearth, realizes that slag-iron separates.Method of the present invention is a continuous production, and material loading taps a blast furnace in batches and slags tap in batches.
This method has following distinguishing feature:
1, because powdered iron ore and coal dust specific surface area are big, uniform distribution in pelletizing, contact closely, to contain briquet faster than iron ore or ferric oxide pellet mass transfer velocity so adopt, and anti-speed height can utilize the high temperature low-quality coal gas realization prereduction of coal-fired generation.
2, fuel makes full use of, and containing briquet has stronger resistance of oxidation.Coal can be realized very high perfect combustion rate at forehearth in present method, and promptly the CO post-combustion rate reaches more than 80%, and the gas excess amount is very low, and the fuel utilization is abundant like this, has improved the energy density in the input stove greatly.The coal-fired in addition high-temperature flue gas that produces the back stove with contain iron ore pelletizing countercurrent flow, thermo-efficiency height, pelletizing reach more than 1000 ℃ after going into stove very soon, can reach 0.45~0.90 at the degree of metalization of stove bottom, back pelletizing.
3, less investment, equipment is simpler, movement-less part in the stove, the productivity height, productive expense is low, can be suitable for wide geographic area and develop middle-size and small-size Iron industry with suiting measures to local conditions.
Description of drawings:
Accompanying drawing 1 is the process flow sheet with coal dust and the direct smelting molten iron of powdered iron ore.
Accompanying drawing 2 is the structural representation of coal dust iron-smelting furnace device.
In the accompanying drawing 1,1,2,3,4 are respectively the storage tank of coal dust, powdered iron ore, flux and binding agent, and 5 are batching and blender, and 6 are spreading, kneading process, and 7 are moulding, and 8 is drying and consolidating, and 9 for sieving, and 10 is coal dust iron-smelting furnace smelting molten iron.
In the accompanying drawing 2,11 is gas blower, and 12 is the coal dust storage tank, 13 is an airduct road, and 14 is the hot blast conveying pipe road, and 15 is forehearth, 16 is back stove furnace bottom dolly, 17 is back stove (shaft furnace), and 18 is preheater, and 19 is chimney heat exchanger, 20 is feeder, 21 is primary air nozzle, and 22 is overfiren air port, and 23,24 are respectively the tap a blast furnace mouth of a river and the slag notch of forehearth.
Forehearth 15 is horizontal or vertical garden column construction, and its length or height are (3~4) with diameter ratio: 1; Rear stove is that section is the shaft furnace of garden shape, and its height is (5~10) with diameter ratio: 1.
Forehearth 15 produces the required heat of ironmaking both as the pulverized coal air cyclone combustion chamber, and again as the molten bath, slag-molten iron is in this separation, overheated. The molten iron discharging of slagging tap respectively. 17 pairs of pelletizings of rear stove carry out preheating and fusing. Rear stove furnace bottom dolly 16 is connected with rear stove 17 with forehearth 15 respectively, and this dolly is movable, is plug in construction, and lays in orbit, can pull out, and separates with forehearth 15 and rear stove 17, is convenient to change and the maintenance furnace bottom. In order to improve the thermal efficiency of forehearth 15, the coal powder burner of whirlwind floated or scroll casing type or sidewall tangent line powder feeding formula can be installed at the primary air nozzle place.
With reference to the accompanying drawings 1, contain coal iron ore pellets needed raw material Iron Ore Powder, coal dust, binding agent and flux by the proportion ingredient of determining after, mix, carry out spreading or kneading and compacting, drying and consolidating under or the natural conditions lower at low temperature (100~200 ℃) is thereupon made and is contained coal iron ore green pellets. Green pellets can enter the coal dust iron-smelting furnace and smelt after sieving.
This contains the coal iron ore pellets after air dry, mean compressive strength greater than 6MPa or 〉=a 290N/ ball, 1.8 meters drop strength 〉=0.8; Pelletizing after 200 ℃ of oven dry, mean compressive strength 〉=7MPa or 〉=a 340N/ ball, 1.8 meters drop strength 〉=0.95.
With reference to the accompanying drawings 2, as follows with the process that contains coal iron ore pellets smelting molten iron:
The wind that air blast 11 is supplied with is sent into the coal dust in the coal dust storage tank mouth through pipeline 13 Forehearth 15 burns, and it is combustion-supporting that the hot blast after chimney heat exchanger 19 and stack gases heat exchange enters forehearth 15 through pipeline 14, and hot blast temperature can reach 100~500 ℃; The cold bonded coal-containing iron ore pellets is furnace roof section preheater 18 after feeder 20 enters, and the hot waste gas that stove 17 is discharged after utilizing carries out preheating; Pelletizing after the preheating enters rear stove 17; High temperature low-quality reducing gas stove 17 after dolly 16 enters that the forehearth burning produces, the coal-bearing pellets countercurrent flow with descending gradually from rear stove top carries out prereduction; Rear furnace temperature can reach 1000~1400 ℃; Pelletizing after prereduction is in rear stove furnace bottom dolly 16 interior fusings and further reduction; Furnace charge after the fusing flows into forehearth 15 and realizes overheated and whole reduction, and carries out slag-molten iron and separate. Every certain interval of time is respectively by slag notch 24 and tapping hole 23 deslagginves and molten iron discharging. The molten iron temperature of producing reaches 1350~1500 ℃. Spray into certain pulvis to molten iron, slag in that forehearth 15 is interior, can adjust the composition of molten iron and slag.
Product molten iron phosphorus content of the present invention can reach 1.0~4.5%, can adjust such as its composition.
The fuel that the present invention uses at forehearth is available gaseous state or liquid fuel also, and such as natural gas or fuel oil, but burner need be done corresponding change. A wind is the carrier gas of fuel coal powder, and Secondary Air is combustion-supporting hot blast or oxygen. Acting as a fuel must be more than 6000 kilocalorie/kilogram with the calorific capacity of coal dust, by the ratio of change total blast volume with contained coal dust amount, can regulate the coefficient of excess air of forehearth 15 interior coal dust firings, so that according to temperature in the arts demand regulating stove and high-temperature flue gas composition, this coefficient is more suitable between being controlled at 0.6~1.05.
In the present invention, if adopt the outer preheating device of stove (as using coal powder burner) Pelletizing is heated to 1200 ℃, and is incubated half an hour, then the pelletizing degree of metalization can reach more than 80%, and the productivity ratio of this device will double.
Embodiment
According to technical process of the present invention and processing parameter, contain coal iron ore pellets and the direct smelt iron water test of coal dust for carrying out twice usefulness in 1 ton the coal dust iron-smelting furnace per hour in productivity.
Contain the composition proportion of coal iron ore pellets and the composition of fuel used coal dust and list table 1 and table 2 respectively in.
Table 1 contains the chemical constitution (weight %) of coal iron ore pellets
Component powdered iron ore coal dust binding agent flux
Heat (batch) number hard coal bituminous coal
1 70
(iron content 65%) 16 473
2 69
(iron content 60%) 18 472
Table 2 bunker coal meal component (weight %)
Heat (batch) number coal fixed carbon ash content volatile matter calorific value kilocalorie/kilogram
1 hard coal 80 11 6 7400
Bituminous coal 48 18 33 6400
2 hard coals 72 18 7 6900
Bituminous coal 44 21 33 6070
The smelting process of twice test is as follows:
During blow-on, after forehearth 15 igniting, use bituminous coal and freezing air burning baker 100 minutes and 80 minutes respectively, after the stove bottom temperature all reaches about 1500 ℃ before and after making, begin from back stove furnace roof feeding in continuous material, every batch of material weighs 100 kilograms, and a small amount of lime block and fluorite etc.Feed intake and put slag for the first time back half an hour.Put primary slag every 10 minutes later on, go out molten iron one time after whenever going out twice slag.
The used coal iron ore pellets amount that contains in twice test, go out iron water amount, molten iron consumption of coal per ton (comprise and contain coal amount and forehearth burning coal in the pelletizing), molten iron per ton consumes ore deposit amount, basicity of slag etc. and all lists table 3 in.
Pelletizing consumption, coal consumption amount in twice test of table 3, go out indexs such as iron water amount
Stove pelletizing amount iron water amount molten iron per ton molten iron slag per ton molten iron temperature iron is received
Consumption of coal consumption ore deposit amount yield
Number kilogram kilogram kilogram kilogram basicity ℃ %
1 2300 900 825 1790 0.5 1350~1430 84.5
2 2100 800 810 1810 0.6 1350~1430 92
In twice test, molten iron carbon content difference 2.4% and 2.5%, sulfur content of hot metal is respectively 0.32% and 0.14%.

Claims (8)

1, a kind of is raw material to contain the coal iron ore pellets, with the coal dust is the method for the direct smelting molten iron of fuel, contain the coal iron ore pellets and enter back stove (17) from back stove furnace roof, heat that fuel combustion produces and reducing gas enter back stove (17) by forehearth (15), with descend gradually from stove (17) top, back contain coal iron ore pellets countercurrent flow, iron ore pellets is reduced gradually, realizes that at forehearth (15) slag-molten iron separates, and is characterized in that:
Contain the coal iron ore pellets at first through after after stove pre-heater on top of furnace (18) preheating, enter back stove (17) prereduction;
Forehearth (15) coal heating is that the coal dust that carries with wind is a fuel, and carries out combustion-supportingly with the hot blast (secondary air) after chimney heat exchanger (19) heat exchange, and the coefficient of excess air of coal dust firing should be controlled between 0.6~1.05;
Through the pelletizing of prereduction after fusing and further reduction in the stove furnace bottom dolly (16), fusing back furnace charge enters forehearth (15) and realizes overheated and whole reduction;
The chemical constitution (weight %) that contains the coal iron ore pellets is: powdered iron ore 60~70%, coal dust 20~30%, binding agent 5~10%, flux 2~5%.
2, method according to claim 1 is characterized in that binding agent is by any two or two or more composition the in cement, spent pulp liquors, lime, water glass, bentonite and the sodium humate.
3, method according to claim 1 is characterized in that the coal dust metabituminous coal accounts for 15~20%, and all the other are hard coal or coke powder or wood charcoal powder.
4, method according to claim 1 is characterized in that powdered iron ore can replace a part by iron scale or iron filings.
5, method according to claim 1 is characterized in that fuel that forehearth uses can be with gaseous state or liquid fuel.
6, technology according to claim 5 is characterized in that gaseous state or liquid fuel can be natural gas, oil fuel.
7, a kind of is raw material to contain the coal iron ore pellets, is the device of the direct smelting molten iron of fuel with the coal dust, comprises forehearth (15) and back stove (17), it is characterized in that:
This device is made up of forehearth (15), back stove (17), back stove furnace bottom dolly (16), preheater (18), chimney heat exchanger (19), feeder (20), gas blower (11) and coal dust storage tank (12);
Forehearth (15) is a horizontal or vertical garden column construction, and its length or height are (3~4) with diameter ratio: 1, and back stove (17) is that section is the shaft furnace of garden shape, its height is (5~10) with diameter ratio: 1;
Back stove furnace bottom dolly (16) is an active, is plug in construction, joins with forehearth (15) and back stove (17) respectively;
Forehearth (15) has cinder notch (24) and the mouth of a river of tapping a blast furnace (23).
8, device according to claim 7, stove furnace bottom dolly (16) is laid in orbit after it is characterized in that, can pull out, change.
CN 88104282 1988-07-19 1988-07-19 Method for smelting molten iron directly from powdered coal and iron ore Expired CN1017628B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 88104282 CN1017628B (en) 1988-07-19 1988-07-19 Method for smelting molten iron directly from powdered coal and iron ore

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Application Number Priority Date Filing Date Title
CN 88104282 CN1017628B (en) 1988-07-19 1988-07-19 Method for smelting molten iron directly from powdered coal and iron ore

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CN1017628B true CN1017628B (en) 1992-07-29

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1059706C (en) * 1996-09-28 2000-12-20 北京科技大学 Gas circulative reduction smelting process for carbon containing pellets

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102168159B (en) * 2011-04-15 2013-05-01 北京科技大学 Reducing agent for carrying out direct reduction roasting on limonite and hematite to produce reduced iron
CN102758046B (en) * 2012-03-20 2014-04-16 辽宁博联特冶金科技有限公司 Shortened production method of coal-based direct reduced iron and equipment therefor
CN102851418A (en) * 2012-09-07 2013-01-02 中冶南方工程技术有限公司 Method for cold consolidation briquetting and briquette blast furnace coking-free smelting
CN103320562A (en) * 2013-06-21 2013-09-25 山西太钢不锈钢股份有限公司 Method for smelting molten iron from dedusting ash
CN104561534A (en) * 2015-01-26 2015-04-29 内蒙古包钢钢联股份有限公司 Magnesium containing fluxed oxide pellets and preparation method thereof
CN108411126B (en) * 2018-05-01 2023-10-17 昆明有色冶金设计研究院股份公司 Titanium slag smelting system and method based on pre-reduction
CN112143911B (en) * 2020-10-09 2023-12-26 新兴铸管股份有限公司 Zinc-containing blast furnace gas ash smelting device and smelting method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1059706C (en) * 1996-09-28 2000-12-20 北京科技大学 Gas circulative reduction smelting process for carbon containing pellets

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