CN1037193C - Method for producing direct reduced iron - Google Patents
Method for producing direct reduced iron Download PDFInfo
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- CN1037193C CN1037193C CN94111002A CN94111002A CN1037193C CN 1037193 C CN1037193 C CN 1037193C CN 94111002 A CN94111002 A CN 94111002A CN 94111002 A CN94111002 A CN 94111002A CN 1037193 C CN1037193 C CN 1037193C
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- pelletizing
- reducing agent
- iron ore
- carbonaceous reducing
- iron
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Abstract
A method for producing direct reduced iron, which is characterized by comprising the following steps: grinding iron ore raw material and solid carbonaceous reducing agent are added with binder to prepare double-layer composite pellets, the inner layer is iron ore, the outer layer is carbonaceous reducing agent, the solid carbonaceous reducing agent in the outer layer pellets is used as reducing agent to reduce iron ore in the inner layer pellets on one hand, and is used as fuel to maintain the temperature of the rotary kiln on the other hand, the pellets are placed in the rotary kiln to be reduced, high-quality direct reduced iron with iron metallization rate of more than 94%, S less than 0.03% and C less than 2% can be obtained, and the capacity of the rotary kiln can reach 0.8t/m3D or more.
Description
What the present invention relates to is to use the solid carbonaceous reducing agent reducing iron ore and obtains the production method of direct-reduced iron.
The at present industrialized in the world technology with solid carbonaceous reducing agent reducing iron ore production direct-reduced iron mainly contains the SL/RN method, ARCAR method etc., its technological principle is to use a rotary kiln to make reactor, iron ore (lump ore) or pellet and part coal are added from rotary kiln, the part coal is thrown into by kiln hood, the kiln body is equipped with blower fan, air-supplied by airduct segmentation in kiln, to keep pyroreaction band long in the kiln, keeping the highest reduction temperature is 1050～1250 ℃, reduction of iron ore can be become degree of metalization greater than 90% direct-reduced iron.The existing subject matter that exists technically with rotary kiln production direct-reduced iron is:
(1). ferrous material is what to separate with solid reductant in kiln, and its chemical reaction process is
(2). and since in kiln in the material movement process iron ore and coal grain granularity and density different, and segregation easily takes place, make reducing atmosphere maldistribution in the kiln, on place and the bed of material surface that iron ore is concentrated,, iron ore reduction speed is restricted because reducing atmosphere is low.
In view of above reason, at present industrializedly make the technology that the rotary kiln of reductive agent is produced direct-reduced iron with coal, the production capacity of reactor is low, generally at 0.4t direct-reduced iron/m
3The level of d causes the investment of ton direct-reduced iron very big, simultaneously all corresponding increase with energy consumption cost of labor force.
The objective of the invention is to: adopt a kind of double-deck pelletizing process, accelerate the rate of reduction of iron ore raw material in rotary kiln, improve unit volume rotary kiln production capacity, reduce the investment of ton direct-reduced iron, cost and energy consumption, and the range of choice of expansion solid reductant.
Technical scheme of the present invention is: ground iron ore raw material and solid carbonaceous reducing agent adding additives are made the two-layer compound pelletizing, internal layer is an iron ore, skin is a solid carbonaceous reducing agent, solid carbonaceous reducing agent one side in the outer pelletizing, acts as a fuel on the other hand and keeps kiln temperature the iron ore reduction in the pelletizing as reductive agent.This pelletizing placed in the rotary kiln reduce, control rotary kiln reduction temperature is 1000～1300 ℃, iron ore reduction in the pelletizing becomes metallic iron, the pelletizing that goes out rotary kiln enters cooling cylinder and cools off solid carbonaceous reducing agent and the ash thereof that the outer remnants of pelletizing are removed in also autogenous grinding, the degree of metalization that can obtain iron is greater than more than 94%, sulphur＜0.03%, the high-quality direct-reduced iron of carbon＜2%.Concrete steps of the present invention are as follows:
1. the preparation of two-layer composite pelletizing:
1). the internal layer that the iron ore or the iron ore concentrate of fine grinding are made double-deck pelletizing at first;
2). the skin of double-deck pelletizing is that above-mentioned pelletizing is wrapped one deck solid carbonaceous reducing agent again, its reductive agent kind can be hard coal, coke powder, bituminous coal, brown coal, charcoal, refinery coke or combination therebetween, and the reductive agent dosage is 5%～150% (butt) of internal layer pelletizing weight.If the solid carbonaceous reducing agent ash fusion point is low, the sulphur content height, can in above-mentioned reductive agent, add materials such as rhombspar, Wingdale, lime, to adjust the ash fusion point of solid carbonaceous reducing agent, make its carbothermic reduction temperature that is higher than iron ore in the pelletizing, prevent pelletizing high temperature ring formation in rotary kiln, and fix sulphur in the solid carbonaceous reducing agent, make its indiffusion go into the internal layer iron ore pellets, pollute and go back original product (direct-reduced iron), its dosage is 0～100% of a solid carbonaceous reducing agent weight.
3). for guaranteeing pellet strength, add binding agent during the system ball, binding agent can be one of following seven kinds of materials or combination therebetween, be pitch, sodium humate, ammonium humate, water glass, sulphate pulp waste liquid, syrup, xylogen silicate, addition is 0.2～15% (butt) of total inventory.
4). pelletizing adopts drying and consolidating, and its temperature is 50～600 ℃, and consolidation time is 3～120 minutes, and moisture content is removed to 0～1.5% of pelletizing weight.
2. rotary kiln reduction:
Above-mentioned two-layer compound pelletizing is sent in the rotary kiln, after pelletizing is heated to above the carbothermic reduction temperature of iron ore in the pelletizing, at first, C in the outer solid carbonaceous reducing agent of pelletizing and the CO in the kiln gas
2The gasification reaction shown in (2) that will react, the CO part that reaction produces enters kiln gas, and a part diffuses into the internal layer pelletizing, with iron ore in the internal layer pelletizing reduction reaction shown in (1) that reacts, the CO that reaction produces
2All enter outer pelletizing, continue by reaction (2) and C reaction, so circulation iron ore Restore All in pelletizing becomes metallic iron.Simultaneously, pelletizing is to make ball after drying and consolidating forms by fine powder material, has big porosity, ectonexine all can be considered vesicular structure, because fine grinding iron ore raw material and solid carbonaceous reducing agent have big specific surface, thereby react and can in whole pelletizing volume, carry out simultaneously, this has just accelerated speed of reaction greatly, has overcome traditional coal-based rotary kiln reducing iron ore and has produced the slow problem of speed of reaction that direct-reduced iron exists.Thereby the production capacity of reactor is improved, and investment, energy consumption and cost obtain big reduction.
In addition, present method reductive agent is to be attached directly to the iron ore raw material skin, therefore, reductive agent and iron ore raw material do not exist in any segregation problem in the reactor, overcome the unbalanced problem of rate of reduction that the segregation of traditional technology solid carbonaceous reducing agent and iron ore raw material causes, guaranteed iron ore raw material fast isostatic rate of reduction in industry kiln.
Moreover because the solid carbonaceous reducing agent of outer pelletizing itself promptly is a solid fuel, therefore furnace charge and kiln gas contact part are solid fuel rather than iron ore raw material all the time in rotary kiln, kiln atmosphere is disturbed little to the reduction of pelletizing inside iron ore like this, the reduction that has guaranteed iron ore raw material is carried out in high reducing atmosphere all the time, the outer field solid fuel of pelletizing can provide energy again simultaneously, keep the required kiln temperature of iron ore reduction, do not need to replenish the energy outward by kiln in addition again, only need to provide in kiln the required oxygen-containing gas of burning to get final product, this just makes technology obtain simplifying.
3. pelletizing is gone into cooling cylinder cooling and outer field residual solid carbonaceous reducing agent of pelletizing and ash thereof are removed in autogenous grinding:
Pelletizing enters cooling cylinder after leaving rotary kiln, by pelletizing being cooled off to the cooling cylinder water spray, pelletizing autogenous grinding in cooling cylinder simultaneously, outer field residual solid carbonaceous reducing agent of pelletizing and ash thereof are separated with the inner layer metal pellet, can not bring impurity in direct-reduced iron, thereby guarantee the quality of direct-reduced iron.The material that goes out cooling cylinder promptly obtains the product direct-reduced iron through fine screening classification and magnetic separator sorting.
Embodiment: carry out following test by above-mentioned steps, obtain following result, the Chemical Composition of used iron ore raw material is: TFe 62.46%, FeO 0.53%, Mn 0.065%, SiO
24.43%, Al
2O
30.34%, CaO 0.07%, MgO 0.05%, S 0.01%, used carbonaceous reducing agent is a coke powder, and Chemical Composition is C 72.16%, fugitive constituent 3.67%, ash 24.17%, S 0.5%, and ash consists of SiO
266.47%, Al
2O
323.90%, CaO 1.12%, MgO 0.73% are milled down to iron ore less than 0.074 millimeter＞80% with ball mill earlier, balling-up in balling disc, during balling-up with addition of 1.5% (butt) sodium humate binding agent, pelletizing moisture 10%, pelletizing particle diameter 8mm.Above-mentioned pelletizing is carried out secondary make ball, wrap one deck less than 0.074 millimeter＞80% coke powder, the coke powder amount is 40% of a pelletizing weight, in coke powder, sneak into ground dolomite less than 0.074 millimeter＞80%, the ground dolomite dosage is 10% of a coke powder weight, with the pelletizing of above-mentioned chemical ingredients and physical specification at 200 ℃ of following drying and consolidatings, send in the axial ventilation rotary kiln of 2 * 30 meters of Ф, the material top temperature is 1080 ℃ in the control kiln, material is kiln residence time 2.5 hours, and the pelletizing of discharging in the kiln promptly obtains the product direct-reduced iron through screening again after the cooling cylinder cooling.Quality product is TFe83.73%, metallic iron 80.29%, and pelletizing degree of metalization 96% contains S 0.025%, and C 0.93%.
Advantage and produce an effect that the present invention has are: (1) is by adopting iron ore, the pelletizing of carbonaceous reducing agent two-layer composite, strengthened the rate of reduction of iron in the pelletizing, reducing agent and iron ore raw material segregation problem in the traditional handicraft rotary kiln have been overcome, pelletizing is reached 1100 ℃ of lower iron ore reduction speed stopped degree of metalization 97% 40 minutes. Because the raising of iron ore reduction speed makes reactor rotary kiln production capacity by the 0.4tDRI/m of traditional handicraft3D brings up to 0.8tDRI/m3More than the d, can use reactive poor coke powder and anthracite to make reducing agent simultaneously, widen the range of choice of technique reducing agent, the present invention can make production unit DRI energy consumption and investment obtain large reduction. (2) feed oxygen-containing gas by rotary kiln end and kiln body airduct, oxidation reaction occurs in the CO that produces in bed of material upper area and pelletizing, the supply heat to the bed of material satisfying the needs of reduction reaction, thereby remove the way that fuel is provided by kiln hood, simplified the structure of reactor. (3) pellet strength is high, the finished ball intensity index can reach: drop strength is greater than 25 times/meter, and compression strength is greater than 400N/ ball, and abrasion resistance index is (0.5mm) less than 1.3%, thereby guarantee pelletizing not efflorescence in reactor, make technique obtain high iron yield. (4) compare with carbon-burdened pellet technique, because this double-deck pelletizing goes out behind the reactor in the skin residual solid carbonaceous reducing agent and ash content and can be removed by the autogenous grinding method easily, thereby can not reduce the iron grade of resultant metal pellet, also can not make the impurity that retains in the solid reductant bring the resultant metal pellet into, guarantee product quality.
Claims (4)
1. method of producing direct-reduced iron, its main process is respectively through grinding, prepare burden, be mixed and made into pelletizing with iron ore or iron ore concentrate, solid carbonaceous reducing agent, send in the rotary kiln after fixed, under 1000～1300 ℃ of temperature, reduction of iron ore in the pelletizing is become metallic iron, it is characterized in that: take secondary system ball method to make the two-layer compound pelletizing with above-mentioned raw materials, concrete steps are, at first ground iron ore or iron ore concentrate are made the internal layer of double-deck pelletizing, and then the outside of this pelletizing wraps one deck levigated solid carbonaceous reducing agent again; All be furnished with binding agent when making the ectonexine of two-layer compound pelletizing, the pelletizing of making adopts drying and consolidating.
2. the method for production direct-reduced iron according to claim 1, it is characterized in that: the solid carbonaceous reducing agent in the outer pelletizing is a kind of or combination therebetween in bituminous coal, hard coal, coke powder, charcoal, refinery coke or the brown coal, and its proportioning is 5%～150% (butt) of internal layer pelletizing weight; Allocate a kind of or combination therebetween in rhombspar, Wingdale, lime, the silica in the outer pelletizing solid carbonaceous reducing agent into, its amount of allocating into is 0%～100% of a solid carbonaceous reducing agent weight.
3. the method for production direct-reduced iron according to claim 1, it is characterized in that: the binding agent that system adds during ball is one of following seven kinds or combination therebetween, be pitch, sodium humate, ammonium humate, water glass, cellulose lye, syrup, xylogen xanthate, addition is 0.2～15% (butt) that is added weight of material.
4. the method for production direct-reduced iron according to claim 1 is characterized in that: pelletizing drying and consolidating temperature is 50～600 ℃, and consolidation time is 3～120 minutes, and moisture removal is arrived 0～1.5% of pelletizing weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94111002A CN1037193C (en) | 1994-05-23 | 1994-05-23 | Method for producing direct reduced iron |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94111002A CN1037193C (en) | 1994-05-23 | 1994-05-23 | Method for producing direct reduced iron |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1114360A CN1114360A (en) | 1996-01-03 |
| CN1037193C true CN1037193C (en) | 1998-01-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN94111002A Expired - Fee Related CN1037193C (en) | 1994-05-23 | 1994-05-23 | Method for producing direct reduced iron |
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| CN (1) | CN1037193C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1294281C (en) * | 2000-04-10 | 2007-01-10 | 株式会社神户制钢所 | Method for producing reduced iron |
| CN103261447A (en) * | 2010-12-15 | 2013-08-21 | 米德雷克斯技术公司 | Method and system for producing direct reduced iron and/or hot metal using brown coal |
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| JP5946201B2 (en) * | 2011-03-21 | 2016-07-05 | テクノロジカル リソーシーズ プロプライエタリー リミテッドＴｅｃｈｎｏｌｏｇｉｃａｌ Ｒｅｓｏｕｒｃｅｓ Ｐｔｙ．Ｌｉｍｉｔｅｄ | Direct smelting method for high sulfur raw materials |
| CN103509938B (en) * | 2012-06-20 | 2015-04-08 | 鞍钢股份有限公司 | Method for preventing over-melting of pre-reduced sinter |
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| CN103088212A (en) * | 2013-02-22 | 2013-05-08 | 陈谦 | Method and equipment for preparing carbon-bearing pellets of coal-based direct reduced iron |
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| US3894865A (en) * | 1970-07-10 | 1975-07-15 | Wienert Fritz Otto | Production of metallurgical pellets in rotary kilns |
| CN85103346A (en) * | 1985-04-20 | 1986-10-15 | 中南工业大学 | Process for direct reduction of briquets bound with high molecular substances |
| CN86105494A (en) * | 1986-08-27 | 1987-07-08 | 昆明工学院 | Brown coal pre-reduction of ore direct steelmaking stocking |
-
1994
- 1994-05-23 CN CN94111002A patent/CN1037193C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3894865A (en) * | 1970-07-10 | 1975-07-15 | Wienert Fritz Otto | Production of metallurgical pellets in rotary kilns |
| CN85103346A (en) * | 1985-04-20 | 1986-10-15 | 中南工业大学 | Process for direct reduction of briquets bound with high molecular substances |
| CN86105494A (en) * | 1986-08-27 | 1987-07-08 | 昆明工学院 | Brown coal pre-reduction of ore direct steelmaking stocking |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1294281C (en) * | 2000-04-10 | 2007-01-10 | 株式会社神户制钢所 | Method for producing reduced iron |
| CN103261447A (en) * | 2010-12-15 | 2013-08-21 | 米德雷克斯技术公司 | Method and system for producing direct reduced iron and/or hot metal using brown coal |
| CN103261447B (en) * | 2010-12-15 | 2016-02-03 | 米德雷克斯技术公司 | Brown coal is used to prepare the method and system of direct-reduced iron and/or molten metal |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1114360A (en) | 1996-01-03 |
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