AU610957B2 - Process of directly reducing iron oxide-containing materials in a rotary kiln - Google Patents
Process of directly reducing iron oxide-containing materials in a rotary kiln Download PDFInfo
- Publication number
- AU610957B2 AU610957B2 AU26953/88A AU2695388A AU610957B2 AU 610957 B2 AU610957 B2 AU 610957B2 AU 26953/88 A AU26953/88 A AU 26953/88A AU 2695388 A AU2695388 A AU 2695388A AU 610957 B2 AU610957 B2 AU 610957B2
- Authority
- AU
- Australia
- Prior art keywords
- rotary kiln
- kiln
- iron oxide
- fraction
- fine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/08—Making spongy iron or liquid steel, by direct processes in rotary furnaces
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Manufacture Of Iron (AREA)
- Muffle Furnaces And Rotary Kilns (AREA)
- Compounds Of Iron (AREA)
Description
prescribed icy itssArticles of Associslison.
16 St4v~5hen K. Plymin 16 12/ 0 Re'gistered Pate.f tutt~ TJHE COMMISSIONER OF PATE.NTS.
Esiwd. Waters Sons, Melbourne,
V)
in Wi; 1 COMMONWEALTH OFAUSTRALIA
U~
PATENTS ACT 1952-69 COMPLETE SPECIFICATION
(ORIGINAL)
Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: 0 0 Velated Art: 0 6 Name of Applicant: Aakress of Applicant: Actual Inventor: 000 Addren for Service: 0900 METALLGESELLSCHAFT AKTIENGESELLSCHAFT Renterweg 14, D-6000 Frankfurt/Main, Federal Republic of Germany GERD ELSENUJEIMER and HERMANN LOMMERT EDW7D. WATERS bONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.
Complete Specification for the invention entitled: PROCESS OF DIRECTLY REDUCING IRON OXIDE-CONTAINING MATrERIALS IN A ROTARY KILN The following statement is a full description of this invention, including the best method of performing it known to 1.
respect of the invention the subject of the application.
DECLARED this. ofA 198 t1h1is .day of A.u sells c h aft Signature.
To: THE CoMMISSIONER OF PATEiTTSt; (Dr. Horst Querl) (Wolfgang Schneider) Edwd. Waters Sons, .A, Melbourne.
-2-
DESCRIPTION
This invention relates to a process of directly reducing iron oxide-containing materials by means of solid carbonaceous reducing agents to form sponge iron in a rotary kiln, wherein iron oxide-containing coarse-grained material is charged into the rotary kiln at its charging end and iron oxide-containing finegrained material is blown into the reducing zone.
0 In the direct reduction of ores in the form t of lumps or pellets in a rotary kiln below the softening oo€ point of the charge to form sponge iron with use of solid 00 0 o 00, carbonaceous reducing agents, the fines below about 5 mm 00 0 0o 0oo are usually sieved off before the material is charged to the rotary kiln. The fines must be sieved off because 0 0o 00o oo the fine fraction would be heated up and reduced more 000o 0 00 quickly on its way through the rotary kiln than the coarse j; o lump material so that-the fine fraction might easily be 0 overheated and/or reoxidized. Particularly in the presence of the coal ash this would result in a softening of the to charge and in incrustation. For a processing of lump ores, a pre-crushed material having a particle size, betwer~n 60 and 100 mm, is often supplied and is then comminuted to a particle size that is not in excess of a specified upper limit between about 15 and 25 mm. The resulting fines below 5 mm may amount to as much as about 29/5of the starting material and can be sold only at a discount or must be dumped and will thus add to the costs of producing sponge iron.
-3- British Patent Specification 1,098,157 discloses a process of directly reducing fine-grained iron ores in which any particles having a size above 5 mm or above 2 mm are sieved off and are charged into the rotary kiln at its charging end whereas the fine-grained ore is blown into the rotary kiln from its discharge end and is distributed on the charge at least over a length of 4 meters. The very fine particles below 0.06 mm are preferably sieved from the fine-grained ore and are ro f
S
f pelletized or briquetted and subsequently charged at the 0 t t 0. charging end. If there is only a small amount of particles ooo 0 00 00 0 in excess of 5 mm or in excess of 2 mm, all of the ore 0 00 o0 o 000 will be blown into the kiln. The very fine fraction 0 0 L' 0A which has been formed into lumps may also be blown 0 00 into the kiln. But the use of that process for a treat- 0 c 0 o o o ment of lump ores will not result in a satisfactory 0 00 operation.
00 0 0 a 0 0 00 It is an object of the invention to o 000000 utilize in the processing of iron oxide-containing o.oe lump materials the fine fraction as economically as o 00000 0 0 possible and without a disadvantage for the process.
That object is accomplished in accordance with the invention in that the iron oxide-containing lump material that is to be charged to the rotary kiln is separated into a coarse fraction, a fine fraction and a very fine fraction at a sieve cut between e i -4- 3 and 6 mm and at a sieve cut between 0.8 and 1.5 mm, the coarse fraction is charged into the rotary kiln at its charging end and the fine fraction is blown into the rotary kiln from its discharge end and is distributed on the charge in the reducing zone. The term "iron oxide-containing lump material" includes lump iron ore as well as pellets consisting of iron ore or of other iron oxide-containing substances, such as dusts collected in steelmaking. In a charge material consisting of pellets, the fine fraction consists of pellet fragments and abraded fines. The term a t 1 "sieve cut" defines a fraction which is sieved off by a 0o04 o 00t S00 sieve having constant sieve opening size in the stated 0 00 JO 0 range. le fine fraction is blown into the rotary kiln at o 0 a 6 00 its discharge end by means of an entraining gas, prefero 00 ably air, so that relatively coarse particles will be 000000 thrown into the kiln over a larger distance than relatively o o 00 fine particles. The rate and the distribution oIthe fine 00 0 C,0 0 o 00 fraction of the material are so adjusted that the material 0 0 0 will be heated up and subscantially reduced throughout its 0 0 0 00 travel to the discharge end. Blowing may be effected by 0 0 means of one or more blowing devices. lie distance over which the material is blown into the kiln may be adjusted aad controlled by a change of the angle of injection of the blowing device and/or by a change of the blowing velocity.
The fine fraction may be blown into the kiln separately or together with solid reducing agents. The rotary kiln may be operabed with countercurrent or cocurrent directions of flow of th hreadtegsatmnosphere i Ud kiln. The fine fraction is blown into the kiln in the direction of flow of the gas atmosphere during countercurrent operation and opposite to the direction of flow of the gas atmosphere during cocurrent operation. The reducing zone of the rotary kiln is that zone in which a reduction to metallic iron is effected.
In accordance with a preferred feature the finL' fraction of the iron oxide-containing material ig blown into the kiln over up to 4F0% of the length of the kiln, measured from the discharge end of/tbhe rotary kiln, and preferably over 15 to 20%l of the length of the kiln. An injection over that length will result in a 0 00 highly effective and fast reduction of the injected. material without a disturbance of the operation of the kiln.
0 49 In accordance with a preferred feature, 0 the fine fraction of the iron oxide-containing material 0 0 6 0 0is blown into the rotary kiln without an addition of o a solid carbonaceous reducing agent. A separate injection 0 0.0 of the fine fraction will permit a particularly effective 0 00 and uniiform distribution on the charge.
In accordance with a preferred feature, the iroL oxide-containing fine fraction is distributed in the upper quadrant of the cross-section of the kiln onto the charge which is tyackling from the wall of the kiln, If the rotary kiln io rotated to 'the left, the fine fraction will be distributed over the charge in the L -(I~L-L -6 right-hand upper quadrant of the cross-section of the kiln so that the injected material will remain on the surface of the trickling charge bed for a longer time before the material is drawn into the bed. As a result, the residence time during which the material is heated on the surface of the charge will be prolonged.
In accordance with a preferred feature the very fine fraction of the iron oxide-containing material is charged into the indirect cooler together with the reduced material which has been discharged from o r S, the rotary kiln. The reduced material discharged from et t the rotary kiln is charged into the indirect cooler with 0o an exclusion of air. As the cooler communicates with the 0o0 °o oreducing gas atmos-phere at the dise a~ge end of the rotary kiln, cooling is effected under reducing conditions.
a o0 0°oo Water is sprinkled onto the outside surface of the cooler.
o 0f 00 Because the very fine fraction is reduced to a high degree °0 in the refractory-lined first part of the cooler, even 0 90 0o 0 the very fine fraction can be processed further without o 0. an additional expenditure and without disadvantages oo00 o for the process.
0 a In accordance with a preferred feature the very fine fraction of the iron oxide-containing material is fed to the transfer chute between the discharge end of the rotary kiln and the charging end of the indirect cooler. This will result in a particularly thorough i -7mixing in a simple manner, the very fine fraction will already be heated in the transfer chute and, as a result, the very fine fraction will be very effectively reduced in the cooler.
In a rotary kiln that is used for cocurrent operation the very fine fraction may alternatively be blown into the rdary kiln at its discharge end. In that case the very fine fraction will be substantially entrained and discharged from the kiln by the kiln atmosphere and 1 will be fed to the cooler or to a bin for hot material.
o In accordance with a further feature the 00ooo 0o very fine fraction is mixed with oil before being fed to 0 oo the cooler. Ihis will increase the carbon content of the 9 00 00 sponge iron.
The invention will be described more in 0 0 0 0 00 detail with reference to an example.
0 0 0 0« The rotary kiln has a length of 80 meters 00 4 o 0 and is 4.8 meters in inside diameter. Seen from the charg- 00000o0 00o ing end, three air nozzle systems and behind them eight I o air-injecting tubes are distributed along the length of 0oO.g the rotary kiln. Each air nozzle system consists of an annular array of air nozzles, which extend through the wall and through the refractory liningof the kiln but do not protrude into the interior of the rotary kiln.
The air-injecting tubes extend radially through the wall and through the refractory lining of/the kiln and their outlet openings are disposed approximately on the center -8line of the kiln and face in the direction of flow of the gas atmosphere. A coal-blowing device, a device for blowing the fine ore fraction and a central burner are provided at the discharge end of the rotary kila, he central burner serves only to heat up the rotary kiln. In the operation of the rotary kiln the charge and the gas atmosphere flow in mutually opposite directions.
The iron ore contains 67.0% Fe and moisture. The ore is first crushed to a particle size below 20 mm and is then sieved off at a sieve cut of 1.0 mm and at a sieve cut of 5.0 mm. The coarse 0 0r fraction having a particle size in excess of 5.0 mm is 00 0 0 0 0 charged into the rotary kiln at its charging end at a 000 rate of 30,500 kg/h. The fine fraction having a particle 0 0 0 0 oo size from 1.0 to 5.0 mm is blown into the rotary kiln at 0 0 0 its discharge end at a rate of 3,000 kg/h together with entraining air through the device for blowing the fine ore and is distributed on the charge over 20% of the o o 0 daoI° length of the kiln, measured from its discharge end. The 0 very fine fraction having a particle size below 1.0 mm, is fed at a rate of 400 kg/h to the transfer chute between the discharge end of the rotary kiln, and the charging end of the indirect cooler after an admixing of oil at a rate of 100 kg/h.
The coal used as a reducing; agent I-io~ ilP*IIN~1 -9has the following composition: Carbon Volatiles Ash Sulfur Moisture Particle size 51.0% 25.0% 24.0% 0.6% 10 0 to 15 mm 0 0 0 0.0 0 009 0 00 o O0 o 00 00 0 0000 00 00 0 So00 0 0 0 0 00 O D t 000 O[0 Coal is charged into the rotary kiln at its charging end at a rate of 12,500 kg/h and is blown into the rotary kiln at its discharge end at a rate of 7,800 kg/h together with entraining air through the coal-blowing device.
Sponge iron having a particle size in excess of 3 mm is discharged from the cooler at a rate of 17,340 kg/h and sponge iron having a particle size below 3 mm is discharged from the cooler at a rate of 5,800 kg/h.
The metallization amounts to 92 to 93 and the carbon content is When the very fine fraction is blown into the rotary kiln together with the fine fraction, the operation will be disturbed by a strong incrustation.
The advantages afforded by the invention reside in that the costs of producing the sponge iron are decreased by the amount which corresponds to the fine fraction which is otherwise lost because it cannot be r i 11 i i m 1 iM, 1111 11111 im xi m ltiMii-in ilmM-in -BIn- ^i charged to the rotary kiln without a disturbance of the operation of the rotary kiln. The throughput rate of the rotary kiln is even increased because the remaining operating conditions are not changed. The specific capital requirement is decreased. That part of the fine fraction which is blown into the kiln takes up less sulfur because a large part of the sulfur introduced by the coal has been expelled or combined as the fines fall on the charge.
o t o a 'r 0 tt 0 04 0 0 o 4 0 4 0 0 S44 o 0 O0 0 00 0 91 OgJ1r'
Claims (8)
1. A process of directly reducing iron oxide-containing materials by means of solid carbonaceous reducing agents to form sponge iron in a rotary kiln, wherein irr;n, oxide-containing coarse-grained material is charged into the rotary kiln at its charging end and iron oxide-containing fine-grained material is blown into the reducing zone, characterized in that the iron oxide-containing lump material that is to be charged to the rotary kiln is separated at a constant sieve cut in the range between 3 and 6 mm and at a constant sieve cut in the range between 0.8 and 1.5 mm as a coarse fraction, a fine fraction and a very fine oo 00 fraction, the coarse fraction is charged into the rotary kiln at its charging end S00 and the fine fraction is blown Into the rotary kiln from its discharge end and is 0distributed on the charge in the reducing zone, in which a reduction to metallic 0000 0 00 00 iron is effected over up to 40 of the length of the kiln, measured from the 0 00 discharge end of the rotary kiln, and reduced material Is discharged from the 00 rotary kiln.
2. A process according to Claim 1, characterized in that the fine fraction of the iron oxide-containing material is blown Into the kiln over 15 to 20 of the length of the kiln, measured from the discharge end of the rotary kiln. C
3. A process according to Claim 1 or 2, characterized in that the fine c fraction of the Iron oxide-containing material is blown Into the rotary kiln without an addition of solid carbonaceous reducing agent. «t SKP/AGB:JJC rotary kiln. /2 1p; I II 1Jl II-I--< 12
4. A process according to any one of claims 1 to 3, characterized in that the iron oxide-containing fine fraction is distributed in the upper quadrant of the cross-section of the kiln into the charge which is trickling from the wall of the kiln.
A process according to any one of claims 1 to 4, further characterized in that the very fine fraction of the iron oxide-containing material is charged into an indirect cooler together with the reduced material which has been discharged from the rotary kiln.
6. A process according to claim 5, characterized in a that the very fine fraction of the iron oxide-containing 0° material is fed to a transfer chute between the discharge o end of the rotary kiln and the charging end of the indirect cooler. a,
7. A process according to claim 5 or 6, characterized in that the very fine fraction is mixed with oil before being fed to the cooler. o0 0
8. A process oi directly reducing iron-otide containing materials by means of solid carbonaceous reducing S agents substantially as hereinbefore described with reference to the example. DATED this 22nd day of November, 1990. METALLGESELLSCHAFT AKTIENGESELLSCHAFT WATERMARK PATENT TRADEI MARK ATTORNEYS 'THE ATRIUM', 2ND FLOOR 290 BURWOOD ROAD HAWTHORN VIC. 3122. 1.52/152/C.Ct i.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3743007 | 1987-12-18 | ||
| DE19873743007 DE3743007A1 (en) | 1987-12-18 | 1987-12-18 | METHOD FOR THE DIRECT REDUCTION OF IRON OXYGEN-CONTAINING MATERIALS IN THE ROTATING THREAD |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2695388A AU2695388A (en) | 1989-06-22 |
| AU610957B2 true AU610957B2 (en) | 1991-05-30 |
Family
ID=6342944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU26953/88A Ceased AU610957B2 (en) | 1987-12-18 | 1988-12-16 | Process of directly reducing iron oxide-containing materials in a rotary kiln |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0321018B1 (en) |
| CN (1) | CN1016618B (en) |
| AU (1) | AU610957B2 (en) |
| BR (1) | BR8805650A (en) |
| DE (2) | DE3743007A1 (en) |
| ES (1) | ES2042722T3 (en) |
| GR (1) | GR3005903T3 (en) |
| IN (1) | IN169929B (en) |
| PT (1) | PT89252B (en) |
| TR (1) | TR23570A (en) |
| ZA (1) | ZA889414B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA947333B (en) * | 1993-09-22 | 1995-05-10 | Rgc Mineral Sands Ltd | Treatment of titaniferous material. |
| GB9523229D0 (en) * | 1995-11-14 | 1996-01-17 | Allied Dust Processing Ltd | Method of processing finely divided material incorporating metal based constituents |
| CN100398669C (en) * | 2005-05-10 | 2008-07-02 | 太原理工大学 | Method of manufacturing low carbon sponge iron using microwave vertical furnace |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1098157A (en) * | 1965-06-23 | 1968-01-10 | Metallgesellschaft Ag | Method of charging a rotary kiln for carrying out endothermic reactions |
| AU525022B2 (en) * | 1979-02-13 | 1982-10-14 | Metallgesellschaft Aktiengesellschaft | Multistage steel making process |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1484260A (en) * | 1965-06-23 | 1967-06-09 | Metallgesellschaft Ag | Process for carrying out endothermic reactions in a rotating tube furnace |
-
1987
- 1987-12-18 DE DE19873743007 patent/DE3743007A1/en not_active Withdrawn
-
1988
- 1988-01-11 IN IN22/CAL/88A patent/IN169929B/en unknown
- 1988-09-16 CN CN88106723A patent/CN1016618B/en not_active Expired
- 1988-10-05 TR TR706/88A patent/TR23570A/en unknown
- 1988-11-02 BR BR888805650A patent/BR8805650A/en not_active IP Right Cessation
- 1988-12-01 ES ES88202755T patent/ES2042722T3/en not_active Expired - Lifetime
- 1988-12-01 EP EP88202755A patent/EP0321018B1/en not_active Expired - Lifetime
- 1988-12-01 DE DE8888202755T patent/DE3873051D1/en not_active Expired - Lifetime
- 1988-12-15 ZA ZA889414A patent/ZA889414B/en unknown
- 1988-12-16 AU AU26953/88A patent/AU610957B2/en not_active Ceased
- 1988-12-16 PT PT89252A patent/PT89252B/en not_active IP Right Cessation
-
1992
- 1992-10-08 GR GR920401646T patent/GR3005903T3/el unknown
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1098157A (en) * | 1965-06-23 | 1968-01-10 | Metallgesellschaft Ag | Method of charging a rotary kiln for carrying out endothermic reactions |
| AU525022B2 (en) * | 1979-02-13 | 1982-10-14 | Metallgesellschaft Aktiengesellschaft | Multistage steel making process |
Also Published As
| Publication number | Publication date |
|---|---|
| IN169929B (en) | 1992-01-11 |
| GR3005903T3 (en) | 1993-06-07 |
| AU2695388A (en) | 1989-06-22 |
| TR23570A (en) | 1990-04-03 |
| EP0321018B1 (en) | 1992-07-22 |
| CN1016618B (en) | 1992-05-13 |
| DE3873051D1 (en) | 1992-08-27 |
| PT89252B (en) | 1993-07-30 |
| BR8805650A (en) | 1989-07-18 |
| ES2042722T3 (en) | 1993-12-16 |
| PT89252A (en) | 1989-12-29 |
| ZA889414B (en) | 1990-08-29 |
| DE3743007A1 (en) | 1989-06-29 |
| CN1033649A (en) | 1989-07-05 |
| EP0321018A1 (en) | 1989-06-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |