CN1204273C - Direct reduction process for rotary kiln - Google Patents
Direct reduction process for rotary kiln Download PDFInfo
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- CN1204273C CN1204273C CN 01114534 CN01114534A CN1204273C CN 1204273 C CN1204273 C CN 1204273C CN 01114534 CN01114534 CN 01114534 CN 01114534 A CN01114534 A CN 01114534A CN 1204273 C CN1204273 C CN 1204273C
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- kiln
- reduction
- binding agent
- rotary kiln
- present
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Abstract
The present invention relates to a direct reduction process for a rotary kiln. In the present invention, a binding agent prepared by the compounding of humate and bentonite is used for pellet fabrication, and after pellet fabrication, a shaft furnace is used as a furnace exterior heating device, to heat pellets entering the kiln. The adopted binding agent of the present invention has the characteristics of reduced addition amount of the bentonite, benefit to the reduction of the cost of the binding agent, enhanced grade of direct reduction iron and enhanced product quality; compared with a grate-kiln grate, the shaft furnace which is used as a kiln exterior l heating device, is good for accelerating the reduction speed of the pellets in the rotary kiln and realizing a thermal regulation of rapid temperature rise and rapid reduction. The present invention has the characteristics of saved investment, low operation cost, high operating rate, long service life, etc. The sulfur content of iron ore concentrates can be broadened to about 1%, and the compressive strength of each of the pellets entering in the kiln can achieve 1000 to 1500N.
Description
Technical field the invention belongs to the ferrous metallurgy field.
Background technology directly reduction is one of two cutting edge technologies of ferrous metallurgy development in this century, and direct-reduced iron is the desirable feedstock of electrosmelting high-quality steel and special steel with addition of steel scrap.For satisfying the needs of smelting high-quality steel and special steel, the output of world's direct-reduced iron grew steadily, from 800,000 tons of 3,862 ten thousand tons of going up 1999 in 1970.90% of direct-reduced iron is to adopt gas-based shaft kiln method and retort process making sponge iron (Sweet natural gas is a reductive agent) to produce at present, the 10%th, and adopt coal-based rotary kiln method (is reductive agent with the coal) to produce.When being the raw material production direct-reduced iron, generally be prepared into oxide pellet or cold-consolidated ball nodulizing earlier, enter the reduction stove then and reduce with the iron ore concentrate.Oxide pellet generally adopts shaft furnace process, belt type roasting machine and chain grate machine-kiln process production, uses wilkinite to make binding agent.In the cooled agglomerated pellet single stage method direct reduction process for rotary kiln, require the iron ore concentrate sulphur content to be lower than 0.03%; The temperature that cooled agglomerated pellet is gone into before the kiln is 50-60 ℃, influences the realization of the fast restore thermal regulation that is rapidly heated, and is the key factor that influences rotary kiln output and quality.
Summary of the invention is accelerated reduction rate in order to improve temperature and the intensity before cooled agglomerated pellet is gone into kiln, improves the pelletizing hot strength, realizes being rapidly heated, fast restore, shortened process, reduces investment outlay, and improves the direct-reduced iron grade, specially proposes the present invention.
The present invention carries out heating outside the stove going into the stokehold to cooled agglomerated pellet, improves the temperature of pellet, enters the rotary kiln reduction then, to accelerate reduction rate, promotes the rise of cooled agglomerated pellet physical strength in rotary kiln, shortens intensity low ebb district.In addition, adopt the outer heating technique of stove, suitably improve stove and heat temperature outward, also can be used for the high-sulfur iron ore concentrate and directly reduce.
The present invention includes iron ore concentrate with addition of binding agent prepare burden, moisten mill, make ball, shaft furnace heating, rotary kiln reduction, magnetic separation process process, the employed binding agent of preparing burden is composited by humate and wilkinite, both mix with arbitrary proportion, and the adding proportion in iron ore concentrate is 0.6-1.2% (weight percent); Adopt shaft furnace to make the outer heating unit of stove after making ball, do thermal source with coal or kiln tail gas, in side combusion chamber's internal combustion heat supply, the kiln pelletizing is gone in heating, and be 40-120min heat-up time, and going into the preceding pelletizing temperature of kiln is 400-950 ℃.
Adopt the present invention, can use the high-sulfur iron ore concentrate directly to reduce as raw material, strong to the adaptability of iron ore concentrate.The used iron ore concentrate sulphur content of general direct reduction should be lower than about 0.03%, and when adopting this technology, because pelletizing has passed through the shaft furnace heat-processed outside the rotary kiln before going into kiln, can remove the sulphur of 80-90%, so the iron ore concentrate sulphur content can be loosened to about 1%.
Improved and gone into the kiln pellet strength.The ultimate compression strength that cooled agglomerated pellet is gone into before the kiln is generally 300-400N/; When chain grate machine-kiln process directly reduced, going into kiln pellet ultimate compression strength was 400-600N/; And among the present invention, go into kiln pelletizing ultimate compression strength and can reach 690-1500N/, go into kiln pelletizing ultimate compression strength and significantly improve.
The pellet temperature improves before going into kiln.Hot-bulb is gone into kiln, helps accelerating the reduction rate of pelletizing in rotary kiln, realizes being rapidly heated the fast restore thermal regulation, improves the hot strength of pelletizing in rotary kiln, improves the operating rate of rotary kiln.
Binding agent is humate and bentonitic mixture, has reduced bentonitic addition, helps reducing the binding agent cost, improves the grade of direct-reduced iron, improves quality product.
Adopt shaft furnace as the outer heating unit of kiln, compare, have reduced investment, running cost is low, operating rate is high and characteristics such as long service life with chain grate machine.
Description of drawings
Fig. 1: process flow diagram of the present invention.
Embodiment
1: iron concentrate grade is TFe 66.5%, and S 0.04%, and granularity is-0.074mm 80%, add mixing behind 1% the compound binding agent, make ball, at shaft furnace internal heating 60min, Heating temperature is 650 ℃, then hot-bulb is put into kiln and reduces, 1050 ℃ of reduction temperatures, recovery time 120min, obtain following index: pelletizing ultimate compression strength 690N/ is individual before going into kiln, 38 times/m of dropping strength, direct-reduced iron iron content 90.15%, MFe85.19%, η
Fe94.5%, S 0.025%.
2: iron concentrate grade is TFe 66.5%, and S 0.04%, and granularity is-0.074mm 80%, add mixing behind 1% the compound binding agent, make ball, at shaft furnace internal heating 40min, Heating temperature is 850 ℃, then hot-bulb is put into kiln and reduces, 1050 ℃ of reduction temperatures, recovery time 120min, obtain following index: go into before the kiln pelletizing ultimate compression strength 890N/, dropping strength is greater than 45 times/m, direct-reduced iron iron content 91.15%, MFe 87.23%, η
Fe95.7%, S 0.020%.
3: iron concentrate grade is TFe 69.1%, S 0.91%, and granularity is-0.074mm 85%, adds mixing behind 1% the compound binding agent, makes ball, at shaft furnace internal heating 60min, Heating temperature is 950 ℃, then hot-bulb is put into kiln and reduces, 1050 ℃ of reduction temperatures, recovery time 120min, obtain following index: pelletizing ultimate compression strength 1500N/ is individual before going into kiln, direct-reduced iron iron content 90.15%, MFe 86.91%, η
Fe96.4%, S 0.014%.
Claims (1)
1. a direct reduction process for rotary kiln comprises the iron ore concentrate batching, and the profit mill is made ball, and the rotary kiln reduction process is characterized in that:
A〉binding agent that uses of blending process is composited by humate and wilkinite, and both mix with arbitrary proportion, and the adding proportion in iron ore concentrate is 0.6-1.2%;
B〉pelletizing is heated after making ball, adopt shaft furnace to make the outer heating unit of stove, do thermal source with coal or kiln tail gas, in side combusion chamber's internal combustion heat supply, the kiln pelletizing is gone in heating, and be 40-120min heat-up time, goes into that the pelletizing temperature is 400-950 ℃ before the kiln.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01114534 CN1204273C (en) | 2001-06-12 | 2001-06-12 | Direct reduction process for rotary kiln |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01114534 CN1204273C (en) | 2001-06-12 | 2001-06-12 | Direct reduction process for rotary kiln |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1390957A CN1390957A (en) | 2003-01-15 |
| CN1204273C true CN1204273C (en) | 2005-06-01 |
Family
ID=4661172
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01114534 Expired - Fee Related CN1204273C (en) | 2001-06-12 | 2001-06-12 | Direct reduction process for rotary kiln |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1204273C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100348736C (en) * | 2003-12-18 | 2007-11-14 | 岳庆丰 | Process for preparing spherical, oblate spherical and diamond shape sponge iron by QF-LY method |
| CN100567509C (en) * | 2005-12-31 | 2009-12-09 | 岳庆丰 | The tunnel furnace of no exterior combustion chamber and combination tunnel furnace thereof are produced direct-reduced iron |
| CN104195278B (en) * | 2014-08-05 | 2016-04-13 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of iron ore shaft furnace-rotary kiln for directly reducing produces iron powder technique |
| CN104195279B (en) * | 2014-09-03 | 2016-04-27 | 中南大学 | A kind of red soil nickel ore prepares the technique of ferronickel |
| CN105002353B (en) * | 2015-08-31 | 2017-09-26 | 中南大学 | The preparation method of the difficult carbon containing dust pellet material of pelletizing and its application in composite agglomeration technology of iron powdered ore |
-
2001
- 2001-06-12 CN CN 01114534 patent/CN1204273C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1390957A (en) | 2003-01-15 |
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