CN103993163A - System and process for producing iron powder from iron ore by direct reduction in belt-type roasting machine and rotary kiln - Google Patents

System and process for producing iron powder from iron ore by direct reduction in belt-type roasting machine and rotary kiln Download PDF

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CN103993163A
CN103993163A CN201410248774.6A CN201410248774A CN103993163A CN 103993163 A CN103993163 A CN 103993163A CN 201410248774 A CN201410248774 A CN 201410248774A CN 103993163 A CN103993163 A CN 103993163A
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pellet
iron ore
rotary kiln
iron
roasting machine
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CN103993163B (en
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王明华
权芳民
展仁礼
高泽宾
雷鹏飞
王欣
马胜军
付涛
王建平
白江虎
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Gansu Jiu Steel Group Hongxing Iron and Steel Co Ltd
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Gansu Jiu Steel Group Hongxing Iron and Steel Co Ltd
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Abstract

The invention provides a system and process for producing iron powder from iron ore by direct reduction in a belt-type roasting machine and a rotary kiln. The system comprises a belt-type roasting machine, a rotary kiln and a heat-resource-free continuous reduction device which are sequentially connected. The process comprises the following process steps: (1) carrying out dry grinding on iron ore and pelletizing; (2) carrying out drying, pre-consolidation and oxidization roasting on the pellets by the belt-type roasting machine to obtain oxidized pellets of which the content of FeO is 1% or less; (3) mixing oxidized pellets with fine coals of which the particle size is 1-3mm, thermally loading the mixture into the rotary kiln, enabling the iron oxides in the oxidized pellets to be reduced to metal iron to obtain metalized pellets; and (4) carrying out grinding-separation on metalized pellets, namely grinding the metalized pellets and carrying out magnetic separation to obtain metalized iron powder of which the iron grade is above 72%. According to the system and process disclosed by the invention, the production process is effectively shortened, the energy consumption is significantly lowered and the production cost is saved.

Description

A kind of iron ore belt type roasting machine-rotary kiln for directly reducing is produced iron powder system and technique
Technical field
The invention belongs to metallurgical and mineral engineering technology field, relate to a kind of iron ore belt type roasting machine-rotary kiln for directly reducing and produce iron powder system and technique.
Background technology
Take acid pellet as raw material, utilize also original production iron powder existing comparatively ripe application at home of blast furnace.And the production unit of acid pellet mainly contains belt type roasting machine, drying grate-rotary kiln-circular cooler, shaft furnace etc., its corresponding process characteristic is as follows:
1, belt type roasting machine acid pellet production technique
In iron and steel enterprise, belt sinter process is grown up by the enlightenment of Dwight-Lloyd sintering machine, is mainly used to produce oxide pellet, its single machine production ability large (6000 ~ 6500t/d), thermo-efficiency is high, uniform in quality, operation, easy to maintenance, can adapt to the various raw materials of roasting.Shortcoming is that material requirement is high, must as fuel, guarantee the oxidizing atmosphere in roasting gas with high heating value gas and heavy oil, high to the stability requirement of raw material, is applicable to large-lot producer and produces.
Pelletizing belt type roasting machine can be divided into successively the dry band of drum, drain band, preheating zone, roasting band and cooling zone in whole length, its process characteristic is: dry, the preheating of (1) pellet roasting, roasting, coolingly all on an equipment, complete the feature such as have that technological process is simple, characteristics of compact layout, required equipment tonnage are light.(2) adopt the dry green-ball of air blast and exhausting mixture length, both strengthened and be dried, improved again the Quality and yield of pellet.(3) each exhausting district bellows hot waste gas, does, after necessary temperature adjusting, to be recycled to forced air drying district or exhausting preheating zone as required.(4) spent air temperture of drying zone is low.Because the hot waste gas of roasting band and cooling zone is for dry, preheating and combustion-supporting, so the hear rate of unit finished product reduces.(5) stronger than shaft furnace to the adaptability of raw material.This is because in whole roasting process, and pelletizing is all in quiet material layer state, can be because of the variation of the intensity of pelletizing in temperature-rise period own and the caused by relative motion powder between ball and ball, thereby belt sinter process can be adapted to all mineral substantially.
2, drying grate-rotary kiln-circular cooler acid pellet production technique
Drying grate-rotary kiln-circular cooler has been widely used among the production of iron ore acid pellet, and its key equipment has been realized regularization and maximization.In production technique, dry, de-crystal water and the preheating of pellet completes on drying grate, and the high-temperature roasting of pellet is carried out in rotary kiln, and the cooling of pellet completes on central cooler.Production feature be strong to adaptability to raw material, green-ball is longer in the high-temperature roasting band residence time, contribute to the raising of product strength and quality uniformity, in production process, secondary energy utilization and environmental protection are better simultaneously, do not need to adopt high-grade heat-resistant steel alloy, energy consumption and the cost of production process are lower, rotary kiln fuel can be used coal gas or coal dust, is easy to realize the maximization of production unit.The deficiency existing in production has: (1) production process completes respectively on three equipment, and production technique and equipment layout are compact not, and production line floor space is larger, and technological process and device structure are comparatively complicated.(2) material is in rotary kiln in flow process, and pellet is easy to efflorescence, and when kiln temperature is too high, material can produce bonding, caking and kiln body ring formation phenomenon.(3) mechanical means of production technique and electrical control investment cost are higher.
3, shaft furnace acid pellet production technique
In iron and steel enterprise, shaft furnace equipment is used for the production of iron ore acid pellet, but in iron ore direct reducing is produced, applies less.In iron ore shaft furnace acid pellet is produced, being dried of pellet, preheating, roasting, coolingly all in a stove, carry out, the high-temp waste gas that fuel produces after external furnace burning evenly sprays in stove along stove cross direction, flue gas fully contacts with material, heating efficiency and pellet output are higher, shaft furnace burning can make full use of various coal gas, there is reduced investment, cycle is short, the features such as instant effect, the problem of its existence is that shaft furnace is to the bad adaptability of raw material (only can adopt magnetite powder to make raw material), second-rate (the perpendicular gas stream in the stove skewness of labour productivity low (equipment enlarging is restricted) and finished pellet, cause the finished ball intensity inhomogeneous) etc., make the more difficult needs that meet large blast furnace smelting of pellet of producing.
And as the blast furnace of reduction apparatus, when original production also, there is following deficiency: (1) coal can only be selected coking coal, has greatly increased production cost; (2) acid pellet can only drop into blast furnace in cold charge mode, cannot utilize the remaining temperature after pellet roasting, thereby increase energy consumption; (3) blast furnace can only be processed concentrate, to the difficult ore dressing that grade is lower, cannot effectively process.
Summary of the invention
The object of the invention is to the problem existing for prior art, provide the iron ore belt type roasting machine that a kind of adaptability to raw material is strong and energy consumption is low-rotary kiln for directly reducing to produce iron powder system.
Another object of the present invention is to provide a kind of iron ore belt type roasting machine-rotary kiln for directly reducing of said system that utilizes to produce iron powder technique.
For this reason, the present invention adopts following technical scheme:
Iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder system, comprises belt type roasting machine, the rotary kiln connecting successively and continues reducing apparatus without thermal source;
Describedly without thermal source continuity reducing apparatus, comprise tank body, described tank body is provided with material inlet, material outlet, the epicoele of described tank body is continuity reduction zone, cavity of resorption is heat transfer zone, in described heat transfer zone, be provided with heat transfer tube, described heat transfer tube has inlet end and exit end, and the epicoele of described tank body is communicated with reducing gas outlet.
Further, described heat transfer tube comprises one-level heat transfer tube and secondary heat exchange pipe, and described one-level heat transfer tube is positioned at secondary heat exchange pipe top, and in tank body, one-level heat transfer tube region forms one-level heat transfer zone, and secondary heat exchange pipe region forms secondary heat exchange district.
Iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder technique, adopts above-mentioned iron ore belt type roasting machine-rotary kiln for directly reducing to produce iron powder system, comprises following processing step:
(1) dry grinding of iron ore, pelletizing: iron ore grinding is accounted for more than 80% to-200 orders, and the powdered iron ore obtaining and the binding agent that is equivalent to powdered iron ore quality 1~3% pelletizing of preparing burden, obtains the pellet that granularity is 8~16mm;
(2) dry preconsolidation and the oxidizing roasting of pellet: pellet is dried to preconsolidation and oxidizing roasting through belt type roasting machine, obtains FeO content at the oxide pellet below 1%;
(3) reduction of oxide pellet: the beans that oxide pellet is 1-3mm with granularity installs in rotary kiln according to 100:25~35 mass ratio mixing after heat; The reduction temperature of controlling oxide pellet is that 1050~1150 ℃, time are 60~120min, and making the reduction of ferrous oxide in oxide pellet is metallic iron, obtains metallized pellet;
(4) metallized pellet mill choosing: metallized pellet ore grinding is carried out to magnetic separation after granularity-200 order accounts for more than 80%, obtain iron grade at more than 80% metallization iron powder.
Further, after step (3) finishes, metallized pellet is inserted without in thermal source continuity reducing apparatus, make metallized pellet utilize self waste heat continue and reduce and pelletizing waste heat is reclaimed, then carry out step (4).
Further, the detailed process of described pelletizing waste heat recovery is: 1050~1150 ℃ of metallized pellets enter into without after thermal source continuity reducing apparatus, in one-level heat transfer zone with the normal temperature air that passes into one-level heat transfer tube after 10~15min heat exchange, the air themperature that one-level heat transfer tube exit end is discharged is brought up to 900~950 ℃; In secondary heat exchange district with the normal temperature air that passes into secondary heat exchange pipe after 15~20min heat exchange, the air themperature that secondary heat exchange pipe exit end is discharged is brought up to 250~350 ℃, then, temperature is reduced to 200 ℃ of following metallized pellets from discharging without thermal source continuity reducing apparatus material outlet.
Further, the dry preconsolidation of the described pellet of step (2) and the detailed process of oxidizing roasting are:
By step (1) pellet from the entrance of belt type roasting machine adds, at the dry band of belt type roasting machine drum, adopt 250~350 ℃ of warm airs of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to heat, pellet enters into and drains band after the forced air drying of 2~4min; Adopt 450~500 ℃ of flue gases extracting out from roasting band to heat pellet draining band, pellet enters into preheating zone after the exhausting of 6~8min is dry; At preheating zone pellet, adopt 900~950 ℃ of warm airs from discharging without thermal source continuity reducing apparatus one-level heat transfer zone to heat, pellet enters into roasting band after 5~7min preheating; At roasting band pellet, adopt 1250~1300 ℃ of flue gases that produce 1050~1150 ℃ of warm air mixed firings of discharging from 950~1050 ℃ of reduction waste gas, cooling zones of rotary kiln discharge to heat, pellet enters into cooling zone after the roasting of 25~35min; At cooling zone pellet, adopt 250~350 ℃ of air of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to carry out cooling, pellet is cooling through 5~10min, after temperature is reduced to 900~950 ℃, from belt type roasting machine, discharges.
Further, in step (3), in the rotary kiln reduction middle and later periods, add Wingdale, the add-on of Wingdale is the 15-30% of step (1) quality of iron ore, and granularity is 3-5mm.Wingdale is mainly as the oxygenation agent of reduction process.
Further, in step (1), by iron ore after ore grinding through high intensity magnetic separation be enriched to iron grade more than 40% after with the caking agent pelletizing of preparing burden.
Further, when raw material adopts rhombohedral iron ore or limonite, by iron ore and coal dust and the binding agent pelletizing of preparing burden, the 1-3% that the add-on of coal dust is quality of iron ore.Adding coal dust can make pellet in burning machine, first reduce (Fe 2o 3→ Fe 30 4, FeO), be then oxidized (Fe 30 4, FeO → α-Fe 2o 3), so can improve iron oxide particle diameter after oxidizing roasting, SiO while making step (4) ore grinding 2deng the impurity being pasted on iron particle, be easy to separation, thereby improve metal recovery rate and iron grade.
Further, in step (1), when raw material adopts magnetite, by iron ore and pore-forming material and the binding agent pelletizing of preparing burden, the 1-2% that the add-on of pore-forming material is quality of iron ore.
Further, in step (1), described binding agent is selected wilkinite, and described pore-forming material is selected starch.
In the present invention, by the oxidizing roasting of belt type roasting machine, can make part Fe in iron ore 30 4, FeO is oxidized to α-Fe 2o 3, FeO content is reduced to below 1%, and ferriferous oxide crystal grain is grown up and pellet strength is improved.Reduction phase, than the reduction of acid pellet blast furnace, rotary kiln reduction can select common coal dust as reductive agent, and blast furnace can only select coking coal to make reductive agent, common coal dust has very large price advantage compared with coking coal; In addition, the acid pellet after roasting can adopt hot charging mode to drop into rotary kiln, under acid pellet high-temperature condition, pack into, and blast furnace can only adopt cold charge mode, thereby effectively save heating energy source; In addition, rotary kiln can be processed low grade ore, and blast furnace can only be processed the concentrate that grade is higher; And the hot flue gas producing in rotary kiln reduction process can be used as the heating source of belt type roasting machine, thereby has further saved the energy.
The present invention also utilizes without thermal source continuity reducing apparatus, the metallized pellet that makes to discharge from rotary kiln utilizes self waste heat further to reduce, thereby further improve degree of metalization, effectively utilized the waste heat of metallized pellet simultaneously, the heat that system is produced has obtained circulation, greatly reduces energy consumption.
To sum up, beneficial effect of the present invention is:
(1) than conventional oxidation pelletizing reducing process, system of the present invention and technique have effectively shortened Production Flow Chart, greatly lower energy consumption, and in system, heat can access recycle;
(2) material can be realized hot delivery and hot charging, has further reduced energy consumption;
(3) reduction can be selected common coal by coal, has saved production cost.
Accompanying drawing explanation
Fig. 1 is the structural representation that iron ore belt type roasting machine of the present invention-rotary kiln for directly reducing is produced iron powder system;
Fig. 2 is that the present invention is without the structural representation of thermal source continuity reducing apparatus;
In figure, 1-belt type roasting machine, 2-rotary kiln, 3-continues reducing apparatus without thermal source, 301-tank body, 302-material inlet, 303-material outlet, 304-continues reduction zone, 305-one-level heat transfer zone, 306-secondary heat exchange district, 307-one-level heat transfer tube, 308-secondary heat exchange pipe, the outlet of 309-reducing gas.
Embodiment
The selection of embodiment material:
Embodiment of the present invention raw materials technology is selected representational low-grade refractory iron ore, specifically selects that iron grade is 31~35%, SiO 2content is 25~48% iron ore; Batching pelletizing time institute coal blending powder selects that fixed carbon content is 45~74%, granularity accounts for more than 80% coal for-200 orders; Reducing roasting rotary kiln selects with coal the coal that fixed carbon content is more than 74%, granularity is 1~3mm; Reduction reaction oxygenation limestone granularity used is 3~5mm.
embodiment 1
As illustrated in fig. 1 and 2, a kind of iron ore belt type roasting machine-rotary kiln for directly reducing is produced iron powder system, comprises belt type roasting machine 1, the rotary kiln 2 connecting successively and continues reducing apparatus 3 without thermal source;
Without thermal source continuity reducing apparatus 3, comprise tank body 301, tank body 301 is provided with material inlet 302, material outlet 303, the epicoele of tank body is continuity reduction zone 304, cavity of resorption is heat transfer zone, in described heat transfer zone, be provided with heat transfer tube, described heat transfer tube has inlet end and exit end, and the epicoele of tank body 301 is communicated with reducing gas outlet 309; Described heat transfer tube comprises one-level heat transfer tube 307 and secondary heat exchange pipe 308, one-level heat transfer tube 307 is positioned at secondary heat exchange pipe 308 tops, and the interior one-level heat transfer tube of tank body 301 307 regions form one-level heat transfer zone 305, secondary heat exchange pipe 308 regions form secondary heat exchange district 306, and the pipe area of secondary heat exchange pipe 308 is greater than one-level heat transfer tube 307.
embodiment 2
Iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder technique, adopts embodiment 1 iron ore belt type roasting machine-rotary kiln for directly reducing to produce iron powder system, comprises following processing step:
(1) dry grinding of iron ore, pelletizing: iron ore adopts rhombohedral iron ore, iron ore grinding to-200 orders are accounted for more than 80%, after ore grinding iron ore high intensity magnetic separation be enriched to iron grade more than 40% after and coal dust, wilkinite by the 100:1:2 pelletizing of preparing burden, obtain the pellet that granularity is 8~16mm;
(2) dry preconsolidation and the oxidizing roasting of pellet: pellet is dried to preconsolidation and oxidizing roasting through belt type roasting machine, obtains FeO content at the oxide pellet below 1%; Detailed process is:
By step (1) pellet from the entrance of belt type roasting machine adds, at the dry band of belt type roasting machine drum, adopt 250~350 ℃ of warm airs of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to heat, pellet enters into and drains band after the forced air drying of 2min; Adopt 450~500 ℃ of flue gases extracting out from roasting band to heat pellet draining band, pellet enters into preheating zone after the exhausting of 6min is dry; At preheating zone pellet, adopt 900~950 ℃ of warm airs from discharging without thermal source continuity reducing apparatus one-level heat transfer zone to heat, pellet enters into roasting band after 6min preheating; At roasting band pellet, adopt 1250~1300 ℃ of flue gases that produce 1050~1150 ℃ of warm air mixed firings of discharging from 950~1050 ℃ of reduction waste gas, cooling zones of rotary kiln discharge to heat, pellet enters into cooling zone after the roasting of 30min; At cooling zone pellet, adopt 250~350 ℃ of air of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to carry out cooling, pellet is cooling through 10min, after temperature is reduced to 900~950 ℃, from belt type roasting machine, discharges;
(3) reduction of oxide pellet: the beans that oxide pellet is 1-3mm with granularity installs in rotary kiln according to 100:30 mass ratio mixing after heat; The reduction temperature of controlling oxide pellet is that 1050~1100 ℃, time are 120min, and the rotary kiln reduction middle and later periods adds Wingdale, and the add-on of Wingdale is 15% of step (1) quality of iron ore; Making the reduction of ferrous oxide in oxide pellet is metallic iron, obtains metallized pellet;
(4) metallized pellet is inserted without in thermal source continuity reducing apparatus by material inlet, making metallized pellet utilize in reduction zone self waste heat continue in continuity reduces and in heat transfer zone, pelletizing waste heat is reclaimed, the detailed process of described waste heat recovery is: 1050~1100 ℃ of metallized pellets enter into without after thermal source continuity reducing apparatus, in one-level heat transfer zone with the normal temperature air that passes into one-level heat transfer tube after 10~15min heat exchange, the air themperature that one-level heat transfer tube exit end is discharged is brought up to 900~950 ℃; In secondary heat exchange district with the normal temperature air that passes into secondary heat exchange pipe after 15~20min heat exchange, the air themperature that secondary heat exchange pipe exit end is discharged is brought up to 250~350 ℃, then, temperature is reduced to 200 ℃ of following metallized pellets from discharging without thermal source continuity reducing apparatus material outlet;
(5) metallized pellet mill choosing: metallized pellet ore grinding is carried out to magnetic separation after granularity-200 order accounts for more than 80%, obtain the iron powder that metallizes.
After measured, the iron grade of resultant metal iron powder is 90%.
embodiment 3
Iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder technique, adopts embodiment 1 iron ore belt type roasting machine-rotary kiln for directly reducing to produce iron powder system, comprises following processing step:
(1) dry grinding of iron ore, pelletizing: iron ore adopts limonite, iron ore grinding to-200 orders are accounted for more than 80%, after ore grinding iron ore high intensity magnetic separation be enriched to iron grade more than 40% after and coal dust, wilkinite by the 100:2:3 pelletizing of preparing burden, obtain the pellet that granularity is 8~16mm;
(2) dry preconsolidation and the oxidizing roasting of pellet: pellet is dried to preconsolidation and oxidizing roasting through belt type roasting machine, obtains FeO content at the oxide pellet below 1%; Detailed process is:
By step (1) pellet from the entrance of belt type roasting machine adds, at the dry band of belt type roasting machine drum, adopt 250~350 ℃ of warm airs of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to heat, pellet enters into and drains band after the forced air drying of 3min; Adopt 450~500 ℃ of flue gases extracting out from roasting band to heat pellet draining band, pellet enters into preheating zone after the exhausting of 8min is dry; At preheating zone pellet, adopt 900~950 ℃ of warm airs from discharging without thermal source continuity reducing apparatus one-level heat transfer zone to heat, pellet enters into roasting band after 5min preheating; At roasting band pellet, adopt 1250~1300 ℃ of flue gases that produce 1050~1150 ℃ of warm air mixed firings of discharging from 950~1050 ℃ of reduction waste gas, cooling zones of rotary kiln discharge to heat, pellet enters into cooling zone after the roasting of 25min; At cooling zone pellet, adopt 250~350 ℃ of air of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to carry out cooling, pellet is cooling through 8min, after temperature is reduced to 900~950 ℃, from belt type roasting machine, discharges;
(3) reduction of oxide pellet: the beans that oxide pellet is 1-3mm with granularity installs in rotary kiln according to 100:25 mass ratio mixing after heat; The reduction temperature of controlling oxide pellet is that 1080~1130 ℃, time are 90min, and the rotary kiln reduction middle and later periods adds Wingdale, and the add-on of Wingdale is 20% of step (1) quality of iron ore; Making the reduction of ferrous oxide in oxide pellet is metallic iron, obtains metallized pellet;
(4) metallized pellet is inserted without in thermal source continuity reducing apparatus, make metallized pellet utilize self waste heat continue and reduce and pelletizing waste heat is reclaimed, the detailed process of described waste heat recovery is with embodiment 2;
(5) metallized pellet mill choosing: with embodiment 2.
After measured, the iron grade of resultant metal iron powder is 93.5%.
embodiment 4
Iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder technique, adopts embodiment 1 iron ore belt type roasting machine-rotary kiln for directly reducing to produce iron powder system, comprises following processing step:
(1) dry grinding of iron ore, pelletizing: iron ore adopts magnetite, iron ore grinding to-200 orders are accounted for more than 80%, after ore grinding iron ore high intensity magnetic separation be enriched to iron grade more than 40% after and starch, wilkinite by the 100:2:2 pelletizing of preparing burden, obtain the pellet that granularity is 8~16mm;
(2) dry preconsolidation and the oxidizing roasting of pellet: pellet is dried to preconsolidation and oxidizing roasting through belt type roasting machine, obtains FeO content at the oxide pellet below 1%; Detailed process is:
By step (1) pellet from the entrance of belt type roasting machine adds, at the dry band of belt type roasting machine drum, adopt 250~350 ℃ of warm airs of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to heat, pellet enters into and drains band after the forced air drying of 4min; Adopt 450~500 ℃ of flue gases extracting out from roasting band to heat pellet draining band, pellet enters into preheating zone after the exhausting of 7min is dry; At preheating zone pellet, adopt 900~950 ℃ of warm airs from discharging without thermal source continuity reducing apparatus one-level heat transfer zone to heat, pellet enters into roasting band after 7min preheating; At roasting band pellet, adopt 1250~1300 ℃ of flue gases that produce 1050~1150 ℃ of warm air mixed firings of discharging from 950~1050 ℃ of reduction waste gas, cooling zones of rotary kiln discharge to heat, pellet enters into cooling zone after the roasting of 35min; At cooling zone pellet, adopt 250~350 ℃ of air of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to carry out cooling, pellet is cooling through 5min, after temperature is reduced to 900~950 ℃, from belt type roasting machine, discharges;
(3) reduction of oxide pellet: the beans that oxide pellet is 1-3mm with granularity installs in rotary kiln according to 100:35 mass ratio mixing after heat; The reduction temperature of controlling oxide pellet is that 1100~1150 ℃, time are 60min, and the rotary kiln reduction middle and later periods adds Wingdale, and the add-on of Wingdale is 30% of step (1) quality of iron ore; Making the reduction of ferrous oxide in oxide pellet is metallic iron, obtains metallized pellet;
(4) metallized pellet is inserted without in thermal source continuity reducing apparatus, make metallized pellet utilize self waste heat continue and reduce and pelletizing waste heat is reclaimed, the detailed process of described waste heat recovery is with embodiment 2;
(5) metallized pellet mill choosing: with embodiment 2.
After measured, the iron grade of resultant metal iron powder is 85.5%.
embodiment 5
Iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder technique, adopts embodiment 1 iron ore belt type roasting machine-rotary kiln for directly reducing to produce iron powder system, comprises following processing step:
(1) dry grinding of iron ore, pelletizing: iron ore adopts rhombohedral iron ore and limonite, iron ore grinding to-200 orders are accounted for more than 80%, after ore grinding iron ore high intensity magnetic separation be enriched to iron grade more than 40% after and coal dust, wilkinite by the 100:2:3 pelletizing of preparing burden, obtain the pellet that granularity is 8~16mm; All the other steps are with embodiment 3.
After measured, the iron grade of resultant metal iron powder is 92.5%.

Claims (10)

1. iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder system, it is characterized in that, comprises belt type roasting machine, the rotary kiln connecting successively and continues reducing apparatus without thermal source;
Describedly without thermal source continuity reducing apparatus, comprise tank body, described tank body is provided with material inlet, material outlet, the epicoele of described tank body is continuity reduction zone, cavity of resorption is heat transfer zone, in described heat transfer zone, be provided with heat transfer tube, described heat transfer tube has inlet end and exit end, and the epicoele of described tank body is communicated with reducing gas outlet.
2. a kind of iron ore belt type roasting machine according to claim 1-rotary kiln for directly reducing is produced iron powder system, it is characterized in that, described heat transfer tube comprises one-level heat transfer tube and secondary heat exchange pipe, described one-level heat transfer tube is positioned at secondary heat exchange pipe top, and one-level heat transfer tube region forms one-level heat transfer zone in tank body, secondary heat exchange pipe region forms secondary heat exchange district.
3. iron ore belt type roasting machine-rotary kiln for directly reducing is produced an iron powder technique, adopts iron ore belt type roasting machine-rotary kiln for directly reducing described in claim 1 to produce iron powder system, it is characterized in that, comprises following processing step:
(1) dry grinding of iron ore, pelletizing: iron ore grinding is accounted for more than 80% to-200 orders, and the powdered iron ore obtaining and the binding agent that is equivalent to powdered iron ore quality 1~3% pelletizing of preparing burden, obtains the pellet that granularity is 8~16mm;
(2) dry preconsolidation and the oxidizing roasting of pellet: pellet is dried to preconsolidation and oxidizing roasting through belt type roasting machine, obtains FeO content at the oxide pellet below 1%;
(3) reduction of oxide pellet: the beans that oxide pellet is 1-3mm with granularity installs in rotary kiln according to 100:25~35 mass ratio mixing after heat; The reduction temperature of controlling oxide pellet is that 1050~1150 ℃, time are 60~120min, and making the reduction of ferrous oxide in oxide pellet is metallic iron, obtains metallized pellet;
(4) metallized pellet mill choosing: metallized pellet ore grinding is carried out to magnetic separation after granularity-200 order accounts for more than 80%, obtain iron grade at more than 72% metallization iron powder.
4. a kind of iron ore belt type roasting machine according to claim 3-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, after step (3) finishes, metallized pellet is inserted without in thermal source continuity reducing apparatus, make metallized pellet utilize self waste heat continue reduction and pelletizing waste heat is reclaimed, then carry out step (4).
5. a kind of iron ore belt type roasting machine according to claim 4-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, the detailed process of pelletizing waste heat recovery is: 1050~1150 ℃ of metallized pellets enter into without after thermal source continuity reducing apparatus, in one-level heat transfer zone with the normal temperature air that passes into one-level heat transfer tube after 10~15min heat exchange, the air themperature that one-level heat transfer tube exit end is discharged is brought up to 900~950 ℃; In secondary heat exchange district with the normal temperature air that passes into secondary heat exchange pipe after 15~20min heat exchange, the air themperature that secondary heat exchange pipe exit end is discharged is brought up to 250~350 ℃, then, temperature is reduced to 200 ℃ of following metallized pellets from discharging without thermal source continuity reducing apparatus material outlet.
6. a kind of iron ore belt type roasting machine according to claim 3-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, the dry preconsolidation of the described pellet of step (2) and the detailed process of oxidizing roasting are:
By step (1) pellet from the entrance of belt type roasting machine adds, at the dry band of belt type roasting machine drum, adopt 250~350 ℃ of warm airs of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to heat, pellet enters into and drains band after the forced air drying of 2~4min; Adopt 450~500 ℃ of flue gases extracting out from roasting band to heat pellet draining band, pellet enters into preheating zone after the exhausting of 6~8min is dry; At preheating zone pellet, adopt 900~950 ℃ of warm airs from discharging without thermal source continuity reducing apparatus one-level heat transfer zone to heat, pellet enters into roasting band after 5~7min preheating; At roasting band pellet, adopt 1250~1300 ℃ of flue gases that produce 1050~1150 ℃ of warm air mixed firings of discharging from 950~1050 ℃ of reduction waste gas, cooling zones of rotary kiln discharge to heat, pellet enters into cooling zone after the roasting of 25~35min; At cooling zone pellet, adopt 250~350 ℃ of air of discharging from the secondary heat exchange district without thermal source continuity reducing apparatus to carry out cooling, pellet is cooling through 5~10min, after temperature is reduced to 900~950 ℃, from belt type roasting machine, discharges.
7. a kind of iron ore belt type roasting machine according to claim 3-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, in step (3), in the rotary kiln reduction middle and later periods, add Wingdale, the add-on of Wingdale is the 15-30% of step (1) quality of iron ore, and granularity is 3-5mm.
8. a kind of iron ore belt type roasting machine according to claim 3-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, in step (1), by iron ore after ore grinding through high intensity magnetic separation be enriched to iron grade more than 40% after with the caking agent pelletizing of preparing burden.
9. a kind of iron ore belt type roasting machine according to claim 3-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, in step (1), when raw material adopts rhombohedral iron ore or limonite, by iron ore and coal dust and the binding agent pelletizing of preparing burden, the 1-3% that the add-on of coal dust is quality of iron ore.
10. a kind of iron ore belt type roasting machine according to claim 3-rotary kiln for directly reducing is produced iron powder technique, it is characterized in that, in step (1), when raw material adopts magnetite, by iron ore and pore-forming material and the binding agent pelletizing of preparing burden, the 1-2% that the add-on of pore-forming material is quality of iron ore.
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CN203960293U (en) * 2014-06-06 2014-11-26 甘肃酒钢集团宏兴钢铁股份有限公司 A kind of iron ore belt type roasting machine-rotary kiln for directly reducing is produced iron powder system

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