CN1248633A - Pre-reduction method and apparatus for fused reduction - Google Patents
Pre-reduction method and apparatus for fused reduction Download PDFInfo
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- CN1248633A CN1248633A CN 99122120 CN99122120A CN1248633A CN 1248633 A CN1248633 A CN 1248633A CN 99122120 CN99122120 CN 99122120 CN 99122120 A CN99122120 A CN 99122120A CN 1248633 A CN1248633 A CN 1248633A
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- shaft furnace
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- 238000000034 method Methods 0.000 title claims abstract description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 17
- 239000002994 raw material Substances 0.000 claims abstract description 12
- 238000001465 metallisation Methods 0.000 claims abstract description 10
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 8
- 239000003034 coal gas Substances 0.000 claims description 31
- 239000008188 pellet Substances 0.000 claims description 30
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 17
- 238000003723 Smelting Methods 0.000 claims description 16
- 238000007599 discharging Methods 0.000 claims description 15
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 230000033228 biological regulation Effects 0.000 claims description 4
- 230000014759 maintenance of location Effects 0.000 claims description 4
- 238000001514 detection method Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 2
- 238000002844 melting Methods 0.000 abstract description 4
- 230000008018 melting Effects 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000011946 reduction process Methods 0.000 abstract description 2
- 238000006722 reduction reaction Methods 0.000 description 90
- 239000007789 gas Substances 0.000 description 25
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 10
- 239000003245 coal Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 3
- 230000036284 oxygen consumption Effects 0.000 description 3
- 238000002791 soaking Methods 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000005201 scrubbing Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 1
- 238000005279 austempering Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
Abstract
The present invention relates to a melting reduction prereduction method and its equipment, belonging to the field of melting reduction technology. Said invention is characterized by that it adopts the cold-bonded briquet whose carbon content is 2-12% as raw material, and according to the characteristics of melting reduction process and used raw material, the existent shaft furnace is renovated and new form of shaft furnace is designed, and the final reduction gas is used as thermal carrier and reducing agent of prereduction process, the CO is used as main reduction gas in the reduction, and the reduction temp. of cold-bonded briquet in shaft furnace is 700-900 deg.C, and the percentage metallization of prereduction product is 50-80%. Said invention possesses the advantages of low gas consumption, high utilization and production efficiency, small equipment valume, smooth and stable furnace condition and easy operation.
Description
The invention belongs to the technical field of smelting reduction. The method is suitable for producing pre-reduced metallized pellets by using iron ore powder and coal powder as the final reduction of smelting reduction.
The direct reduction method as the smelting reduction pre-reduction means is mainly characterized in that coal gas generated by a smelting reduction final reduction furnace is used as a reducing agent and a heat carrier, pre-reduction furnace charge is heated and reduced into pre-reduction furnace charge with a certain metallization rate in a solid state, and then the pre-reduction furnace charge enters the final reduction furnace for further reduction and melting. The direct reduction is used as a means of smelting reduction pre-reduction, has the advantages of reducing the heat load of smelting reduction final reduction, improving the heat efficiency and the productivity of a final reduction furnace, reducing the energy consumption of the whole process, prolonging the service life of the final reduction furnace and the like, and is also an essential stage of two-step smelting reduction.
In the prior smelting reduction pre-reduction technology, the method is a COREX method CN (ZL87108012) developed by an austempering process, which is relatively close to the method, and is characterized in that an MIDREX type shaft furnace (US37346123) is used as a pre-reduction reactor, oxidized pellets or lump ore areused as raw materials, and high-temperature (1100 ℃) high-purity coal gas (CO + H2 is more than 90 percent) generated by final reduction is used; the temperature of inlet gas is about 850 ℃, the reduction temperature is about 800 ℃, and the metallization rate of the product is more than 90%. The method uses the oxidized pellets or lump ore as raw materials, and requires high metallization rate, low gas diffusion speed and low reduction speed of products, so that the retention time of furnace materials in the shaft furnace is overlong, the gas thermal efficiency and the chemical energy utilization rate are reduced, the gas quantity required by the metallized pellets of unit yield is very large, the pre-reduction equipment is overhigh, and excessive residual gas is generated, so that the whole process has low productivity, high energy consumption and oxygen consumption and large investment, and compared with the existing blast furnace, the method is lack of competitiveness.
The invention aims to provide a method and a device for smelting reduction prereduction, which have the advantages of low energy consumption and oxygen consumption, high equipment production efficiency and high energy utilization rate.
The invention adopts the following technical scheme: the cold-bonded carbon-containing pellets are used as raw materials, final reducing gas is used as a heat carrier and a reducing agent, and CO is mainly used in the reducing gas; the reduction reaction is carried out in a modified shaft furnace. The smelting reduction pre-reduction device of the invention comprises: a feeding system, a pre-reduction shaft furnace, a coal gas system and a discharging device.
The invention adopts the raw material of cold-bonded pellets containing 2-12% of carbon, and the concrete composition (weight percentage); 80-93% of iron ore concentrate, 2-15% of coal powder and 2-10% of binder.
The invention adopts final reduction coal gas mainly comprising CO as a heat carrier and a reducing agent, namely the coal gas comprises the following components (in weight percent): CO 60-90%, H25-30％，CO22-15％，N21-8% and the balance of O2The charging temperature of coal gas is 800-950 ℃, and the reduction gas amount is 800-1500M3The product of the reaction product of,
the reduction temperature of the invention is 700-900 ℃, the total retention time of the pellets in the shaft furnace is 2-6 hours, and the retention time of the pellets in the high-temperature reduction zone is 30-90 minutes.
When the pre-reduction shaft furnace discharges materials to the final reduction iron bath furnace, the discharging temperature is 700-.
The pre-reduction of the invention adopts medium reduction degree, namely the metallization rate of the pre-reduced ore at the outlet of the pre-reduction shaft furnace reaches 50 to 80 percent.
The invention discloses a smelting reduction pre-reduction device, which comprises a feeding system, a pre-reduction shaft furnace, a coal gas system and a discharging device; the pre-reduction shaft furnace comprises a drying zone, a preheating zone, a reduction zone and a soaking zone, and a furnace body consisting of the drying zone, the preheating zone and the reduction zone has a certain cone angle (5-20 ℃); the gas system consists of a hot gas main pipe, an annular pipe, a gas inlet and a final reduction gas detection and temperature regulation device, the gas inlet and the horizontal direction have a certain inclination angle (0-30 degrees), the discharging equipment comprises a discharging machine and a discharging pipe, and the discharging pipe is hermetically connected with the inlet of the final reduction furnace. The ratio of the height of the reduction zone of the pre-reduction shaft furnace to the inner diameter of the reduction zone is less than 4: 1.
The method and the device of the invention are utilized to produce the pre-reduction furnace charge required by final reduction, and are characterized in that: using cold-bonded pellets containing 2-12% of carbon as a raw material; final reduction coal gas mainly containing CO is used as a heat carrier and a reducing agent; the high-temperature reduction temperature in the shaft furnace is determined to be 50-100 ℃ lower than the softening temperature of the pellets; the inlet temperature of the pre-reduction coal gas is 50-100 ℃ higher than the reduction temperature, the CO + H2 is more than 80%, and the coal gas quantity simultaneously meets the requirements of pre-reduction chemical balance and thermal balance.
The cold-bonded carbon-containing pellets are reduced in the shaft furnace through the following processes:
(1) drying
The cold-bonded carbon-containing pellets are arranged on the upper part of the shaft furnace, heated to 300-400 ℃ by ascending coal gas, and the residual moisture in the cold-bonded carbon-containing pellets is evaporated.
(2) Preheating
The pellets enter a preheating zone after passing through a drying zone and are heated to 700-950 ℃ from 300-400 ℃. In the process, the indirect reduction reaction of reducing high-valence iron oxide into low-valence iron oxide and a small amount of metallic iron by CO and H2 in the coal gas occurs, and meanwhile, the coal in the pellets undergoes decomposition reaction. The main reduction reactions taking place in the preheating zone are as follows:
(3) reduction of
The pellets enter a reduction zone after passing through a preheating zone, and the reduction temperature is within the range of 700-900 ℃. In the reduction zone, the reaction of iron oxide reduced to metallic iron by CO and H2 in coal gas mainly occurs, and carbon in the pellets also participates in the reduction reaction at a small part. The reduction reaction is as follows:
(4) soaking heat
The pellets enter a soaking zone after passing through a reduction zone, the temperature is slightly reduced, and a small amount of FeO is reduced into metallic iron. The metallization rate of the pellet ore at the outlet of the pre-reduction shaft furnace reaches 50-80%.
Compared with the prior art, the invention has the following advantages:
(1) as the carbon-containing pellets are used as raw materials, the coal powder in the raw materials becomes a diffusion channel of gas, the diffusion condition of the gas is improved, the reduction speed is obviously accelerated, and the utilization coefficient of the equipment is high.
(2) The invention takes final reduction coal gas as a heat carrier and a reducing agent, the coal gas mainly contains CO, the total heat efficiency of the reduction reaction is more than zero, the heat load of the pre-reduction shaft furnace is reduced, the heat efficiency of the coal gas is improved, the coal gas consumption is reduced, and the energy consumption and the oxygen consumption of the whole process are reduced.
(3) The metallizationrate of the product is at the stage of the fastest reduction speed, the production efficiency of the equipment is greatly improved, the equipment volume of a unit product can be more than half lower than that of a Midrex type shaft furnace, the clearance height is obviously reduced, and the equipment investment can be correspondingly reduced.
(4) Because the shaft furnace type in the prior art is improved, the furnace body has a certain taper angle, the reduction expansion rate of the carbon-containing pellets is generally lower, and the pellets can be ensured to move forward even if a small amount of expansion exists.
(5) Because the pre-reduction furnace charge contains higher carbon content, the reduction process of FeO and the carburization of iron can be accelerated after the pre-reduction furnace charge enters a final reduction furnace, and the phenomenon of foaming slag can be reduced.
(6) The coal gas is allowed to have higher oxidation degree, and the requirement on the quality of the coal gas is not high. The residual gas amount is small, and the energy utilization rate is high.
The invention is further described with reference to the accompanying drawings.
FIG. 1 is a schematic view of a smelting reduction prereduction furnace.
The device comprises a raw material bin 1, an inclined bridge 2, a hopper 3, a distributor 4, a shaft furnace 5, a feeder 6, a blanking pipe 7, a gas main pipe 8, a gas ring pipe 9, a gas inlet 10, a gas outlet pipe 11, a final reduction gas detection and temperature regulation device 12, a cyclone dust collector 13, a Venturi scrubbing tower 14, a pressure regulation valve 15 and an underground bin 16.
The cold-bonded pellets are loaded into a hopper (3) from a raw material bin (1) through an inclined bridge (2), enter a shaft furnace (5) through a distributing device (4), are changed into pre-reduction furnace charge with a certain metallization rate in the shaft furnace (5) after passing through a preheating zone and a reduction zone respectively, and are discharged into a discharging pipe (7) through a discharging machine (6) and finally enter a final reduction furnace. After the final reduction coal gas is adjusted to a preset temperature, the final reduction coal gas enters a coal gas ring pipe (9) through a coal gas main pipe (8), then enters the shaft furnace through a coal gas inlet (10) which is uniformly distributed on the ring pipe and has a certain inclination angle, the coal gas heats and reduces the carbon-containing pellets in the rising process, the temperature is reduced to 300-400 ℃, the carbon-containing pellets are led out through a coal gas leading-out pipe (11), and the carbon-containing pellets are treated by a cyclone dust collector (13) and a Venturi scrubbing tower (14) and then are used for other purposes.
Examples
Three tests were carried out in a small shaft furnace with an internal diameter of 200MM using the pre-reduction method described in the present invention. The temperature of the furnace gas entering the furnace is about 900 ℃, and the reduction temperature zone is about 800 ℃. The compositions of the cold-bonded carbon-containing pellets are shown in Table 1, the reducing gas components are shown in Table 2, and the test results are shown in Table 3. TABLE 1 composition of cold-bonded carbon-containing pellets (% by weight)
TABLE 2 reducing gas composition (% by weight)
TABLE 3 test results
| Serial number | 67 fine iron powder ％ | Pulverized coal Cfix＝78.33％ | Binder (Dry basis) |
| 1 | 85.99 | 10.63 | 3.38 |
| 2 | 88.59 | 7.81 | 3.6 |
| 3 | 91.36 | 5.4 | 3.24 |
| CO | H2 | N2 | CO2 | O2 |
| 89.33 | 7.41 | 2.51 | 0.1 | 0.65 |
| Serial number | TFe(％) | MFe(％) | Metallization rate (％) | Amount of gas used Nm3/T | Coefficient of utilization T/d*m3 |
| 1 | 80.05 | 58.02 | 72.48 | 1034 | 13.7 |
| 2 | 82.12 | 61.02 | 74.3 | 1102 | 13.4 |
| 3 | 83.6 | 58.27 | 69.7 | 998 | 14.3 |
Claims (4)
1. A smelting reduction prereduction method is to use coal gas produced by a final reduction furnace as a reducing agent and a heat carrier, heat prereduction furnace charge, reduce the prereduction furnace charge into prereduction furnace charge with certain metallization rate in a solid state, and then enter the final reduction furnace for further reduction and smelting, and is characterized in that:
(1) cold-bonded pellets containing 2-12% of carbon are used as raw materials;
(2) the final reduction coal gas mainly containing CO is used as a heat carrier and a reducing agent, namely: the coal gas comprises the following components in percentage by weight: CO 60-80%, H25-30％，CO25-15％，N21-8％；
(3) The temperature of coal gas entering the furnace is 800-950 ℃, and the reduction gas amount is 800-1500M3The product of/T;
(4) the reduction temperature is 700 ℃ and 900 ℃, and the total retention time of the pellets in the shaft furnace is 2-6 hours;
(5) when the pre-reduction shaft furnace discharges materials to the final reduction iron bath furnace, the discharging temperature is 700-;
(6) the pre-reduction adopts a medium reduction degree, namely the metallization rate of the pre-reduced ore at the outlet of the pre-reduction shaft furnace reaches 50 to 80 percent;
2. a smelting reduction pre-reduction device is characterized in that: the device comprises a feeding system, a pre-reduction shaft furnace, a coal gas system and a discharging device; the feeding system comprises a skip car, a feeding inclined bridge, a hopper and a distributor, the pre-reduction shaft furnace consists of a preheating zone and a reduction zone, and a furnace body consisting of the preheating zone and the reduction zone has a certain cone angle (5-20 degrees); the gas system consists of a hot gas main pipe, an annular pipe, a gas inlet and a final reduction gas detection and temperature regulation device, the gas inlet and the horizontal direction have a certain inclination angle (0-30 degrees), the discharging equipment comprises a discharging machine and a discharging pipe, and the discharging pipe is hermetically connected with the inlet of the final reduction furnace.
3. The apparatus according to claim 2, characterized in that the ratio of the height of the reduction zone of the pre-reduction shaft furnace to the inner diameter of the reduction zone is less than 4: 1.
4. The apparatus of claim 2, wherein the pre-reduction furnace is a furnace discharge mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99122120A CN1089115C (en) | 1999-10-27 | 1999-10-27 | Pre-reduction method and apparatus for fused reduction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN99122120A CN1089115C (en) | 1999-10-27 | 1999-10-27 | Pre-reduction method and apparatus for fused reduction |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1248633A true CN1248633A (en) | 2000-03-29 |
| CN1089115C CN1089115C (en) | 2002-08-14 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN99122120A Expired - Fee Related CN1089115C (en) | 1999-10-27 | 1999-10-27 | Pre-reduction method and apparatus for fused reduction |
Country Status (1)
| Country | Link |
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| CN (1) | CN1089115C (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102559981A (en) * | 2012-01-05 | 2012-07-11 | 中冶东方工程技术有限公司 | Iron making method and device by virtue of gas-based smelting reduction |
| CN102864265A (en) * | 2012-09-24 | 2013-01-09 | 中南大学 | Method for recycling gas-base direct reducted tail gas |
| CN104374669A (en) * | 2014-11-19 | 2015-02-25 | 东北大学 | Direct reduction and smelting reduction linked testing device and use method thereof |
| CN104404189A (en) * | 2014-11-24 | 2015-03-11 | 中冶南方工程技术有限公司 | Method for producing ferrochromium alloy by two-step-process smelting reduction of ferrochromium mineral powder |
| CN106918686A (en) * | 2017-03-14 | 2017-07-04 | 东北大学 | It is a kind of for studying the experimental provision that fine ore reacts during exercise |
| CN110191967A (en) * | 2016-11-23 | 2019-08-30 | 环境清洁技术有限公司 | Via the low temperature direct-reduction of the metal oxide in situ for generating reducibility gas |
-
1999
- 1999-10-27 CN CN99122120A patent/CN1089115C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102559981A (en) * | 2012-01-05 | 2012-07-11 | 中冶东方工程技术有限公司 | Iron making method and device by virtue of gas-based smelting reduction |
| CN102864265A (en) * | 2012-09-24 | 2013-01-09 | 中南大学 | Method for recycling gas-base direct reducted tail gas |
| CN104374669A (en) * | 2014-11-19 | 2015-02-25 | 东北大学 | Direct reduction and smelting reduction linked testing device and use method thereof |
| CN104374669B (en) * | 2014-11-19 | 2017-02-22 | 东北大学 | Direct reduction and smelting reduction linked testing device and use method thereof |
| CN104404189A (en) * | 2014-11-24 | 2015-03-11 | 中冶南方工程技术有限公司 | Method for producing ferrochromium alloy by two-step-process smelting reduction of ferrochromium mineral powder |
| CN110191967A (en) * | 2016-11-23 | 2019-08-30 | 环境清洁技术有限公司 | Via the low temperature direct-reduction of the metal oxide in situ for generating reducibility gas |
| CN106918686A (en) * | 2017-03-14 | 2017-07-04 | 东北大学 | It is a kind of for studying the experimental provision that fine ore reacts during exercise |
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| Publication number | Publication date |
|---|---|
| CN1089115C (en) | 2002-08-14 |
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Granted publication date: 20020814 Termination date: 20121027 |