A direct reduction ironmaking apparatus and method using a secondary reduction reaction

Abstract

The present application relates to smelting technology technical field, specifically to a kind of direct reduction iron-making equipment and iron-making method using secondary reduction reaction.The direct reduction iron-making equipment includes sequentially arranged and sequentially connected raw material feeding device, direct reduction iron-making furnace and direct reduction iron-making tank according to the flow of iron-making raw material processing, and gas separation device is further provided between the direct reduction iron-making furnace and the direct reduction iron-making tank for transporting the mixed gas of carbon monoxide and carbon dioxide generated in the direct reduction iron-making furnace into the direct reduction iron-making tank for secondary reduction reaction after separating carbon dioxide;Wherein, the raw material feeding device includes iron ore feeder, coke or coal feeder, and iron ore preheater is provided on the iron ore feeder for preheating iron ore.The present application improves the production efficiency of direct reduction iron-making, and reduces the equipment investment cost of direct reduction iron-making.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, specifically to a direct reduction ironmaking equipment and method employing a two-stage reduction reaction. Background Technology

[0002] Traditional ironmaking uses blast furnaces. During the reduction process in blast furnace ironmaking, when iron and oxygen separate from the iron ore, a considerable amount of elements such as Si, Mn, and C also enter the molten iron. Therefore, the molten iron must undergo oxidation refining to remove excess and impurity elements. The refined steel then needs to be deoxidized, which complicates the smelting process, generates more polluting gases, and causes unnecessary energy and raw material consumption.

[0003] The recently developed short-process hydrogen-based shaft furnace-electric arc furnace smelting process uses a hydrogen-based shaft furnace for ironmaking, employing hydrogen and coke oven gas as reducing agents to reduce iron from iron ore particles within the shaft furnace. The ore is then further smelted into steel in an electric arc furnace. This short-process smelting technology significantly reduces energy consumption and is environmentally friendly.

[0004] However, the aforementioned production line using a hydrogen-based vertical shaft furnace-electric furnace still suffers from the drawback of high equipment investment. Furthermore, during the reduction of iron in a hydrogen-based vertical shaft furnace, the raw materials are piled up inside the furnace, resulting in uneven airflow and significantly reducing the uniformity of heating and the rate of the reduction reaction. This leads to a longer reduction reaction time and lower production efficiency.

[0005] To address the aforementioned issues, our company has developed an electric furnace for smelting with a rotary stirring furnace structure and its application, and has filed a patent application with the Chinese Patent Office (application number 202311208298.0) to solve the problems of long reduction reaction time and low production efficiency in existing ironmaking technologies. This invention is a further improvement based on the aforementioned patent application. Summary of the Invention

[0006] To further address the aforementioned problems, this invention proposes a direct reduction ironmaking equipment and method employing a two-stage reduction reaction, aiming to improve the production efficiency of direct reduction ironmaking and reduce the equipment investment cost. The specific technical solution is as follows:

[0007] A direct reduction ironmaking apparatus employing a secondary reduction reaction includes a raw material feeding device, a direct reduction ironmaking furnace, and a direct reduction ironmaking ladle, which are sequentially arranged and connected according to the ironmaking raw material processing flow. A gas separation device is also provided between the direct reduction ironmaking furnace and the direct reduction ironmaking ladle to separate the carbon dioxide from the mixed gas of carbon monoxide and carbon dioxide generated in the direct reduction ironmaking furnace before conveying it to the direct reduction ironmaking ladle for a secondary reduction reaction. The raw material feeding device includes an iron ore feeder and a coke or coal feeder, and an iron ore preheater is provided on the iron ore feeder for preheating the iron ore.

[0008] Preferably, the iron ore preheater is an electromagnetic induction heating preheater.

[0009] In this invention, the gas separation device includes a carbon monoxide and carbon dioxide separation tank, a mixed gas conveying pipeline connecting the direct reduction blast furnace and the carbon monoxide and carbon dioxide separation tank, and a carbon monoxide conveying pipeline connecting the carbon monoxide and carbon dioxide separation tank and the direct reduction blast furnace; valves are respectively installed on the mixed gas conveying pipeline and the carbon monoxide conveying pipeline.

[0010] In this invention, the raw material feeding device, the direct reduction ironmaking furnace, and the direct reduction ironmaking ladle are arranged sequentially from top to bottom. The direct reduction ironmaking furnace is set on an elevated platform, and an upper support is also set on the elevated platform. The raw material feeding device is set on the upper support, and the carbon monoxide and carbon dioxide separator is set on the elevated platform.

[0011] The elevated platform is supported on the lower support.

[0012] In this invention, the direct reduction blast furnace is a rotary stirring furnace with built-in electric heating elements. The rotating cylinder of the rotary stirring furnace serves as the furnace body of the direct reduction blast furnace, and the cylinder cover plate of the rotary stirring furnace serves as the furnace body cover plate of the direct reduction blast furnace. A refractory material layer is provided on the inner wall of the rotating cylinder of the rotary stirring furnace, and a refractory material layer is provided on the side of the cylinder cover plate facing the rotating cylinder. A refractory material layer is provided on the outer surface of the stirring impeller and stirring shaft of the rotary stirring furnace.

[0013] In this invention, a first fluid dynamic sealing assembly is provided between the cylinder cover plate and the rotating cylinder, and a second fluid dynamic sealing assembly is provided between the stirring shaft and the cylinder cover plate.

[0014] In this invention, the lower discharge channel of the rotating cylinder of the direct reduction blast furnace and the upper inlet channel of the direct reduction blast furnace are vertically connected, and a third fluid dynamic sealing assembly is provided at the vertically connected joint between the lower discharge channel of the rotating cylinder of the direct reduction blast furnace and the upper inlet channel of the direct reduction blast furnace.

[0015] In this invention, the first fluid dynamic sealing assembly includes a first annular water groove disposed on the cylinder cover plate and a first annular ring connected to the rotating cylinder, wherein the first annular ring on the rotating cylinder is inserted into the first annular water groove on the cylinder cover plate to form a water seal.

[0016] In this invention, the second fluid dynamic sealing assembly includes a second annular water groove disposed on the cylindrical cover plate and a second annular ring connected to the stirring shaft, wherein the second annular ring on the stirring shaft is inserted into the second annular water groove on the cylindrical cover plate to form a water seal.

[0017] In this invention, the third fluid dynamic sealing assembly includes a third annular water tank disposed on the direct reduction blast furnace and a third annular ring disposed at the lower discharge valve of the direct reduction blast furnace. The third annular ring at the lower discharge valve of the direct reduction blast furnace is inserted into the third annular water tank on the direct reduction blast furnace, thereby forming a water seal.

[0018] To improve the reliability of the fluid dynamic seal assembly, a cooling device can be installed on it. The cooling device can be a circulating cooling heat exchange tube immersed in an annular water tank, and the circulating heat exchange tube can be connected to a refrigeration device (such as a water tower, refrigeration unit, etc.).

[0019] Preferably, an overflow gas negative pressure recovery hood is provided around the first fluid dynamic sealing assembly, the second fluid dynamic sealing assembly and the third fluid dynamic sealing assembly.

[0020] In this invention, valves are respectively installed on the lower discharge channel of the rotating cylinder of the direct reduction blast furnace and the upper inlet channel of the direct reduction blast furnace.

[0021] As a further improvement of the present invention, a movable platform for replacing the direct reduction blast furnace ladle is provided below the ladle. The movable platform is provided with a lifting platform for docking or separating the lower discharge channel of the rotating cylinder of the direct reduction blast furnace from the upper inlet channel of the direct reduction blast furnace ladle. The direct reduction blast furnace ladle is placed on the lifting platform.

[0022] Preferably, the mobile platform is a reciprocating mobile platform or a ring mobile platform, and the reciprocating mobile platform or the ring mobile platform is provided with a number of lifting platforms arranged at intervals.

[0023] In this invention, the iron ore feeder includes an iron ore preheating storage tank and an iron ore conveying pipeline connecting the iron ore preheating storage tank and the direct reduction blast furnace; the coke or coal feeder includes a coke or coal storage tank and a coke or coal conveying pipeline connecting the coke or coal storage tank and the direct reduction blast furnace; valves are respectively installed on the iron ore conveying pipeline and the coke or coal conveying pipeline.

[0024] In this invention, the outer shell of the direct reduction blast furnace and the direct reduction blast furnace is provided with a heat insulation material layer to reduce heat loss during the reduction reaction.

[0025] A method for ironmaking using a direct reduction ironmaking apparatus employing a two-stage reduction reaction includes the following steps:

[0026] (1) Material preparation and preheating: Add the iron ore dispersion to the iron ore preheating tank, add coke or coal to the coke or coal storage tank, turn on the iron ore preheater on the iron ore preheating tank, and preheat the iron ore dispersion in the iron ore preheating tank.

[0027] (2) Primary reduction ironmaking: The preheated iron ore dispersion, coke or coal dispersion is transferred to the direct reduction ironmaking furnace through a valve. Under the heating of the electric heating element in the direct reduction ironmaking furnace, and under the combined action of the rotation of the rotating cylinder and the rotation of the stirring impeller in the direct reduction ironmaking furnace, the materials in the furnace are fully stirred and mixed and uniformly heated, and carbon monoxide and carbon dioxide gas are generated. The iron ore is gradually reduced to iron by the carbon monoxide gas, thus forming primary reduction ironmaking. During the primary reduction ironmaking process, the gas separation device receives the mixed gas of carbon monoxide and carbon dioxide from the direct reduction ironmaking furnace and separates the carbon monoxide and carbon dioxide.

[0028] (3) Secondary reduction ironmaking: The material that has undergone primary reduction ironmaking in the direct reduction ironmaking furnace is transferred to the direct reduction ironmaking ladle through a valve. At the same time, carbon monoxide separated by the gas separation device is transferred to the direct reduction ironmaking ladle through a valve and mixed with the material. The reduction reaction continues using the heat of the carbon monoxide gas and the material itself. The remaining unreduced iron ore in the direct reduction ironmaking ladle is further reduced to iron by the carbon monoxide gas, thus forming secondary reduction ironmaking.

[0029] The ironmaking method of the present invention using a direct reduction ironmaking equipment with a secondary reduction reaction further includes the following steps after the secondary reduction ironmaking in step (3):

[0030] (4) Transfer and replacement of direct reduction ironmaking ladle: disconnect the carbon monoxide delivery pipeline of the gas separation device from the direct reduction ironmaking ladle, drive the lifting platform on the moving platform to descend, disconnect the direct reduction ironmaking ladle from the direct reduction ironmaking furnace, and move the direct reduction ironmaking ladle that has completed secondary reduction ironmaking from below the direct reduction ironmaking furnace through the moving platform; then use the moving platform with the lifting platform to move the next empty direct reduction ironmaking ladle to below the direct reduction ironmaking furnace and dock it with the direct reduction ironmaking furnace, and connect the carbon monoxide delivery pipeline of the gas separation device to the empty direct reduction ironmaking ladle.

[0031] (5) Continuous production of direct reduction smelting: Repeat steps (1) to (4) to achieve continuous production of direct reduction iron smelting.

[0032] Preferably, the preheating temperature in the iron ore preheating tank is 700-800℃, the reduction reaction temperature in the direct reduction blast furnace is set to 1300℃, and the reduction reaction temperature in the direct reduction blast furnace is not lower than 900℃.

[0033] The working principle of the direct reduction ironmaking process using a direct reduction furnace and a direct reduction ironmaking ladle in this invention is as follows: when coke or coal is mixed with iron ore in the furnace or ladle, a reduction reaction occurs at a high temperature to produce reduced iron. During the reduction reaction, carbon monoxide and carbon dioxide are continuously produced. Carbon monoxide acts as a reducing agent for the iron ore, allowing the reduction reaction to continue. The carbon monoxide required for the direct reduction ironmaking ladle is directly supplied from the carbon monoxide and carbon dioxide mixture generated in the direct reduction furnace after separation by a gas separation device.

[0034] To improve the efficiency of the reduction reaction in ironmaking, a certain amount of carbon monoxide can be introduced into the direct reduction ironmaking furnace at the beginning of the reduction reaction, and the supply of carbon monoxide can be stopped when the reaction reaches self-equilibrium in the later stage.

[0035] In this invention, since the mobile platform is equipped with a number of lifting platforms arranged at intervals, multiple empty direct reduction blast furnace ladles can be pre-placed on each lifting platform, thereby realizing large-scale continuous production of direct reduction blast furnace.

[0036] The beneficial effects of this invention are:

[0037] First, the present invention provides a direct reduction ironmaking equipment and method employing a two-stage reduction reaction. Firstly, a direct reduction ironmaking furnace is used to achieve primary reduction ironmaking at a relatively high reduction temperature, which can reduce most of the iron ore raw material into iron. Then, a direct reduction ironmaking ladle is used to achieve secondary reduction ironmaking within the ladle, utilizing the high-temperature residual heat from the primary reduction ironmaking process. This significantly increases the iron yield. After the secondary reduction ironmaking, the final product in the direct reduction ironmaking ladle is solid dispersed reduced iron with a purity of over 90%, which can be used as a raw material for subsequent steelmaking.

[0038] Secondly, the present invention provides a direct reduction ironmaking equipment and method employing a two-stage reduction reaction. The direct reduction ironmaking furnace used in the primary reduction reaction is a novel rotary stirring furnace with built-in electric heating elements. This rotary stirring furnace enables the raw materials in the furnace to be uniformly mixed through stirring by the stirring impeller, and allows the iron ore dispersion to fully contact with carbon monoxide gas. It has the advantages of short reduction reaction time and fast speed, thereby improving the production efficiency of the direct reduction ironmaking reaction.

[0039] Third, the present invention provides a direct reduction ironmaking equipment and method that employs a two-stage reduction reaction. The iron ore raw material is first preheated by an iron ore preheater before entering the direct reduction ironmaking furnace, which can greatly shorten the time of the first reduction reaction in the direct reduction ironmaking furnace, thereby further improving the production efficiency of the direct reduction ironmaking reaction.

[0040] Fourth, the present invention provides a direct reduction ironmaking equipment and method that employs a secondary reduction reaction. During production, multiple empty direct reduction ironmaking ladles can be pre-configured to achieve large-scale, high-efficiency, and continuous production of direct reduction ironmaking.

[0041] Fifth, the present invention provides a direct reduction ironmaking equipment and method employing a secondary reduction reaction. Through a fluid dynamic sealing assembly, the interior of the direct reduction ironmaking furnace and the interior of the direct reduction ironmaking ladle are isolated from the outside air, allowing the reduction reaction to proceed in an oxygen-free, enclosed space. This ensures the normal operation of the direct reduction reaction and reduces the generation of harmful gases. Furthermore, the fluid dynamic sealing assembly also prevents excessive pressure within the furnace or ladle, thereby improving the safety of the smelting reaction.

[0042] Sixth, in the direct reduction ironmaking equipment and method of the present invention, which employs a secondary reduction reaction, the reaction gas overflowing from the water tank of the fluid dynamic sealing component in the furnace or ladle is specially collected and treated by the overflow gas negative pressure recovery hood and the waste heat is utilized, without causing adverse effects on the surrounding environment.

[0043] Seventh, the present invention provides a direct reduction ironmaking equipment and method using a secondary reduction reaction. Compared with the traditional blast furnace-converter ironmaking method, its process flow is shorter and the emission of harmful gases is greatly reduced, making it more environmentally friendly.

[0044] Eighth, the present invention provides a direct reduction ironmaking equipment and method using a secondary reduction reaction. Compared with the structure of a hydrogen-based vertical furnace, the overall structure of the direct reduction ironmaking equipment is simpler, the investment cost is relatively lower, and a single set of equipment can achieve small-to-medium scale production of 100,000 tons per year, thereby reducing the total investment cost of the project and minimizing investment risk. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of a direct reduction ironmaking equipment using a two-stage reduction reaction according to the present invention;

[0046] Figure 2 Yes, yes Figure 1 A schematic diagram of the specific structure of the direct reduction blast furnace in China.

[0047] In the diagram: 1. Raw material feeding device; 2. Direct reduction blast furnace; 3. Direct reduction blast furnace ladle; 4. Gas separation device; 5. Iron ore feeder; 6. Coke or coal feeder; 7. Iron ore preheater; 8. Carbon monoxide and carbon dioxide separator; 9. Mixed gas conveying pipeline; 10. Carbon monoxide conveying pipeline; 11. Overhead platform; 12. Upper support; 13. Electric heating element; 14. Rotating cylinder; 15. Cylinder cover plate; 16. Agitator impeller; 17. Agitator shaft; 18. First fluid dynamic sealing assembly; 19. The... 20. Second-stage fluid dynamic sealing assembly; 21. Third-stage fluid dynamic sealing assembly; 22. Moving platform; 23. Lifting platform; 24. Iron ore preheating storage tank; 25. Iron ore conveying pipeline; 26. Coke or coal storage tank; 27. Coke or coal conveying pipeline; 28. Lower support; 29. ​​Base; 30. Column; 31. Crossbeam plate; 32. Rotary drive mechanism; 33. Belt drive mechanism or gear drive mechanism; 34. Bearing housing component; 35. Feed port; 36. Overflow gas negative pressure recovery hood; 37. Discharge valve; 38. First annular water tank; 39. First annular ring; 40. Second annular water tank; 41. Second annular ring; 42. Third annular water tank; 43. Third annular ring. Detailed Implementation

[0048] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0049] Example 1:

[0050] like Figures 1 to 2The illustration shows an embodiment of a direct reduction ironmaking apparatus employing a secondary reduction reaction according to the present invention. It includes a raw material feeding device 1, a direct reduction ironmaking furnace 2, and a direct reduction ironmaking ladle 3, which are sequentially arranged and connected according to the ironmaking raw material processing flow. A gas separation device 4 is also provided between the direct reduction ironmaking furnace 2 and the direct reduction ironmaking ladle 3 to separate the carbon dioxide from the mixed gas of carbon monoxide and carbon dioxide generated in the direct reduction ironmaking furnace 2 before conveying it to the direct reduction ironmaking ladle 3 for a secondary reduction reaction. The raw material feeding device 1 includes an iron ore feeder 5 and a coke or coal feeder 6, and an iron ore preheater 7 is provided on the iron ore feeder 5 for preheating the iron ore.

[0051] Preferably, the iron ore preheater 7 is an electromagnetic induction heating preheater.

[0052] In this embodiment, the gas separation device 4 includes a carbon monoxide and carbon dioxide separation tank 8, a mixed gas conveying pipeline 9 connecting the direct reduction blast furnace 2 and the carbon monoxide and carbon dioxide separation tank 8, and a carbon monoxide conveying pipeline 10 connecting the carbon monoxide and carbon dioxide separation tank 8 and the direct reduction blast furnace 3; valves are respectively provided on the mixed gas conveying pipeline 9 and the carbon monoxide conveying pipeline 10.

[0053] In this embodiment, the raw material feeding device 1, the direct reduction ironmaking furnace 2, and the direct reduction ironmaking ladle 3 are arranged sequentially from top to bottom. The direct reduction ironmaking furnace 2 is arranged on the overhead platform 11, and an upper support 12 is also arranged on the overhead platform 11. The raw material feeding device 1 is arranged on the upper support 12, and the carbon monoxide and carbon dioxide separator 8 is arranged on the overhead platform 11.

[0054] The overhead platform 11 is supported on the lower support 27.

[0055] In this embodiment, the direct reduction ironmaking furnace 2 is a rotary stirring smelting furnace with an internal electric heating element 13. The rotating cylinder 14 of the rotary stirring smelting furnace serves as the furnace body of the direct reduction ironmaking furnace 2, and the cylinder cover plate 15 of the rotary stirring smelting furnace serves as the furnace body cover plate of the direct reduction ironmaking furnace 2. A refractory material layer is provided on the inner wall of the rotating cylinder 14 of the rotary stirring smelting furnace, and a refractory material layer is provided on the side of the cylinder cover plate 15 facing the rotating cylinder 14. A refractory material layer is provided on the outer surface of the stirring impeller 16 and the stirring shaft 17 of the rotary stirring smelting furnace.

[0056] In this embodiment, a first fluid dynamic sealing assembly 18 is provided between the cylinder cover plate 15 and the rotating cylinder 14, and a second fluid dynamic sealing assembly 19 is provided between the stirring shaft 17 and the cylinder cover plate 15.

[0057] In this embodiment, the lower discharge channel of the rotating cylinder 14 of the direct reduction blast furnace 2 and the upper inlet channel of the direct reduction blast furnace 3 are vertically connected, and a third fluid dynamic sealing assembly 20 is provided at the vertically connected joint between the lower discharge channel of the rotating cylinder 14 of the direct reduction blast furnace 2 and the upper inlet channel of the direct reduction blast furnace 3.

[0058] In this embodiment, the first fluid dynamic sealing assembly 18 includes a first annular water groove 38 disposed on the cylindrical cover plate 15 and a first annular ring 39 connected to the rotating cylindrical body 14, and the first annular ring 39 on the rotating cylindrical body 14 is inserted into the first annular water groove 38 on the cylindrical cover plate 15 to form a water seal.

[0059] In this embodiment, the second fluid dynamic sealing assembly 19 includes a second annular water groove 40 disposed on the cylindrical cover plate 15 and a second annular ring 41 connected to the stirring shaft 17, and the second annular ring 41 on the stirring shaft 17 is inserted into the second annular water groove 40 on the cylindrical cover plate 15 to form a water seal.

[0060] In this embodiment, the third fluid dynamic sealing assembly 20 includes a third annular water tank 42 disposed on the direct reduction blast furnace 3 and a third annular ring 43 disposed at the lower discharge valve of the direct reduction blast furnace 2. The third annular ring 43 at the lower discharge valve of the direct reduction blast furnace 2 is inserted into the third annular water tank 42 on the direct reduction blast furnace 3 to form a water seal.

[0061] To improve the reliability of the fluid dynamic seal assemblies 18, 19, and 20, a cooling device can be installed on them. The cooling device can be a circulating cooling heat exchange tube immersed in an annular water tank 38, 40, and 42, and the circulating heat exchange tube can be connected to a refrigeration device (such as a water tower or chiller).

[0062] Preferably, an overflow gas negative pressure recovery cover 36 is provided on the periphery of the first fluid dynamic sealing assembly 18, the second fluid dynamic sealing assembly 19 and the third fluid dynamic sealing assembly 20 respectively.

[0063] In this embodiment, valves are respectively installed on the lower discharge channel of the rotating cylinder 14 of the direct reduction blast furnace 2 and the upper inlet channel of the direct reduction blast furnace ladle 3.

[0064] As a further improvement of this embodiment, a mobile platform 21 for replacing the direct reduction blast furnace 3 is also provided below the direct reduction blast furnace 3. The mobile platform 21 is provided with a lifting platform 22 for docking or separating the lower discharge channel of the rotating cylinder 14 of the direct reduction blast furnace 2 from the upper inlet channel of the direct reduction blast furnace 3. The direct reduction blast furnace 3 is disposed on the lifting platform 22.

[0065] Preferably, the mobile platform 21 is a reciprocating mobile platform or a ring mobile platform, and the reciprocating mobile platform or the ring mobile platform is provided with a number of lifting platforms 22 arranged at intervals.

[0066] In this embodiment, the iron ore feeder 5 includes an iron ore preheating storage tank 23 and an iron ore conveying pipeline 24 connecting the iron ore preheating storage tank 23 and the direct reduction blast furnace 2; the coke or coal feeder 6 includes a coke or coal storage tank 25 and a coke or coal conveying pipeline 26 connecting the coke or coal storage tank 25 and the direct reduction blast furnace 2; valves are respectively installed on the iron ore conveying pipeline 24 and the coke or coal conveying pipeline 26.

[0067] In this embodiment, the outer shell of the direct reduction blast furnace and the direct reduction blast furnace is provided with a heat insulation material layer to reduce heat loss during the reduction reaction.

[0068] Example 2:

[0069] An ironmaking method using the direct reduction ironmaking equipment employing a secondary reduction reaction as described in Example 1 includes the following steps:

[0070] (1) Material preparation and preheating: Add the iron ore dispersion to the iron ore preheating tank 23, add coke or coal to the coke or coal storage tank 25, turn on the iron ore preheater 7 on the iron ore preheating tank 23, and preheat the iron ore dispersion in the iron ore preheating tank 23.

[0071] (2) Primary reduction ironmaking: The preheated iron ore dispersion and coke or coal dispersion are transferred to the direct reduction ironmaking furnace 2 through valves. Under the heating of the electric heating element 13 in the direct reduction ironmaking furnace 2, and under the combined action of the rotation of the rotating cylinder 14 and the stirring impeller 16 in the direct reduction ironmaking furnace 2, the materials in the furnace are fully stirred and mixed and uniformly heated, and carbon monoxide and carbon dioxide gas are generated. The iron ore is gradually reduced to iron by the carbon monoxide gas, thus forming primary reduction ironmaking. During the primary reduction ironmaking process, the gas separation device receives the mixed gas of carbon monoxide and carbon dioxide from the direct reduction ironmaking furnace 2 and separates the carbon monoxide and carbon dioxide.

[0072] (3) Secondary reduction ironmaking: The material that has undergone primary reduction ironmaking in the direct reduction ironmaking furnace 2 is transferred to the direct reduction ironmaking ladle 3 through a valve. At the same time, the carbon monoxide separated by the gas separation device 4 is transferred to the direct reduction ironmaking ladle 3 through a valve and mixed with the material. The reduction reaction continues using the heat of the carbon monoxide gas and the material itself. The remaining unreduced iron ore in the direct reduction ironmaking ladle 3 is further reduced to iron by the carbon monoxide gas, thus forming secondary reduction ironmaking.

[0073] The ironmaking method of a direct reduction ironmaking equipment using a secondary reduction reaction in this embodiment also includes the following steps after the secondary reduction ironmaking in step (3):

[0074] (4) Transfer and replacement of direct reduction ironmaking ladle: Disconnect the connection between the carbon monoxide conveying pipeline 10 of the gas separator 4 and the direct reduction ironmaking ladle 3, drive the lifting platform 22 on the moving platform 21 to descend, disconnect the connection between the direct reduction ironmaking ladle 3 and the direct reduction ironmaking furnace 2, and move the direct reduction ironmaking ladle 3, which has completed secondary reduction ironmaking, out from under the direct reduction ironmaking furnace 2 through the moving platform 21; then use the moving platform 21 with the lifting platform 22 to move the next empty direct reduction ironmaking ladle 3 to under the direct reduction ironmaking furnace 2 and dock it with the direct reduction ironmaking furnace 2, and connect the carbon monoxide conveying pipeline 10 of the gas separator 4 to the empty direct reduction ironmaking ladle 3.

[0075] (5) Continuous production of direct reduction smelting: Repeat steps (1) to (4) to achieve continuous production of direct reduction iron smelting.

[0076] Preferably, the preheating temperature in the iron ore preheating storage tank 23 is 700-800℃, the reduction reaction temperature in the direct reduction ironmaking furnace 2 is set at 1300℃, and the reduction reaction temperature in the direct reduction ironmaking ladle 3 is not lower than 900℃.

[0077] In this embodiment, the working principle of direct reduction ironmaking using a direct reduction furnace 2 and a direct reduction ironmaking ladle 3 is as follows: when coke or coal is mixed with iron ore in the furnace or ladle, a reduction reaction occurs at a high temperature to produce reduced iron. During the reduction reaction, carbon monoxide and carbon dioxide are continuously generated. Carbon monoxide acts as a reducing agent for the iron ore, allowing the reduction reaction to continue. The carbon monoxide required by the direct reduction ironmaking ladle 3 is directly supplied from the carbon monoxide and carbon dioxide mixture generated in the direct reduction furnace 2 after separation by a gas separation device.

[0078] To improve the efficiency of the ironmaking reduction reaction, a certain amount of carbon monoxide can be introduced into the direct reduction ironmaking furnace 2 at the beginning of the reduction reaction, and the supply of carbon monoxide can be stopped when the reaction reaches self-equilibrium in the later stage.

[0079] In this embodiment, since the mobile platform 21 is provided with a number of lifting platforms 22 arranged at intervals, multiple empty direct reduction ironmaking ladles 3 can be pre-placed on each lifting platform 22, thereby realizing large-scale continuous production of direct reduction ironmaking.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A direct reduction ironmaking apparatus employing a two-stage reduction reaction, characterized in that, The system includes a raw material feeding device, a direct reduction blast furnace, and a direct reduction blast furnace ladle, which are arranged and connected sequentially according to the ironmaking raw material processing flow. A gas separation device is also provided between the direct reduction blast furnace and the direct reduction blast furnace to separate the carbon dioxide from the mixed gas of carbon monoxide and carbon dioxide generated in the direct reduction blast furnace before conveying it to the direct reduction blast furnace ladle for a secondary reduction reaction. The raw material feeding device includes an iron ore feeder and a coke or coal feeder, and an iron ore preheater is provided on the iron ore feeder for preheating the iron ore. The direct reduction blast furnace is a rotary stirring smelting furnace with built-in electric heating elements. The rotating cylinder of the rotary stirring smelting furnace serves as the furnace body of the direct reduction blast furnace, and the cylinder cover plate of the rotary stirring smelting furnace serves as the furnace body cover plate of the direct reduction blast furnace. A refractory material layer is provided on the inner wall of the rotating cylinder of the rotary stirring smelting furnace, and a refractory material layer is provided on the side of the cylinder cover plate facing the rotating cylinder. A refractory material layer is provided on the outer surface of the stirring impeller and stirring shaft of the rotary stirring smelting furnace.

2. The direct reduction ironmaking equipment employing a secondary reduction reaction according to claim 1, characterized in that, The iron ore preheater is an electromagnetic induction heating preheater.

3. The direct reduction ironmaking equipment employing a secondary reduction reaction according to claim 2, characterized in that, The gas separation device includes a carbon monoxide and carbon dioxide separation tank, a mixed gas conveying pipeline connecting the direct reduction blast furnace and the carbon monoxide and carbon dioxide separation tank, and a carbon monoxide conveying pipeline connecting the carbon monoxide and carbon dioxide separation tank and the direct reduction blast furnace; valves are respectively installed on the mixed gas conveying pipeline and the carbon monoxide conveying pipeline.

4. The direct reduction ironmaking equipment employing a secondary reduction reaction according to claim 3, characterized in that, The raw material feeding device, the direct reduction ironmaking furnace, and the direct reduction ironmaking ladle are arranged sequentially from top to bottom. The direct reduction ironmaking furnace is set on an elevated platform, and an upper support is also set on the elevated platform. The raw material feeding device is set on the upper support, and the carbon monoxide and carbon dioxide separator is set on the elevated platform.

5. The direct reduction ironmaking equipment employing a secondary reduction reaction according to claim 1, characterized in that, A first fluid dynamic sealing assembly is provided between the cylinder cover plate and the rotating cylinder, and a second fluid dynamic sealing assembly is provided between the stirring shaft and the cylinder cover plate.

6. The direct reduction ironmaking equipment employing a secondary reduction reaction according to claim 5, characterized in that, The lower discharge channel of the rotating cylinder of the direct reduction blast furnace and the upper inlet channel of the direct reduction blast furnace are vertically connected, and a third fluid dynamic sealing assembly is provided at the vertically connected joint between the lower discharge channel of the rotating cylinder of the direct reduction blast furnace and the upper inlet channel of the direct reduction blast furnace.

7. A direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 6, characterized in that, An overflow gas negative pressure recovery hood is provided around the first fluid dynamic sealing assembly, the second fluid dynamic sealing assembly, and the third fluid dynamic sealing assembly, respectively.

8. A direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 6, characterized in that, Valves are respectively installed on the lower discharge channel of the rotating cylinder of the direct reduction blast furnace and the upper inlet channel of the direct reduction blast furnace ladle.

9. A direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 8, characterized in that, Below the direct reduction blast furnace ladle, there is a mobile platform for replacing the direct reduction blast furnace ladle. The mobile platform is equipped with a lifting platform for docking or separating the lower discharge channel of the rotating cylinder of the direct reduction blast furnace from the upper inlet channel of the direct reduction blast furnace ladle. The direct reduction blast furnace ladle is placed on the lifting platform.

10. A direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 9, characterized in that, The mobile platform is a reciprocating mobile platform or a ring mobile platform, and the reciprocating mobile platform or the ring mobile platform is provided with a number of lifting platforms arranged at intervals.

11. A direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 1, characterized in that, The iron ore feeder includes an iron ore preheating tank and an iron ore conveying pipeline connecting the iron ore preheating tank and the direct reduction blast furnace; the coke or coal feeder includes a coke or coal storage tank and a coke or coal conveying pipeline connecting the coke or coal storage tank and the direct reduction blast furnace; valves are respectively installed on the iron ore conveying pipeline and the coke or coal conveying pipeline.

12. A method for ironmaking using a direct reduction ironmaking apparatus employing a secondary reduction reaction as described in any one of claims 1 to 11, characterized in that, Includes the following steps: (1) Material preparation and preheating: Add the iron ore dispersion to the iron ore preheating tank, add coke or coal to the coke or coal storage tank, turn on the iron ore preheater on the iron ore preheating tank, and preheat the iron ore dispersion in the iron ore preheating tank. (2) Primary reduction ironmaking: The preheated iron ore dispersion, coke or coal dispersion is transferred to the direct reduction ironmaking furnace through a valve. Under the heating of the electric heating element in the direct reduction ironmaking furnace, and under the combined action of the rotation of the rotating cylinder and the rotation of the stirring impeller in the direct reduction ironmaking furnace, the materials in the furnace are fully stirred and mixed and uniformly heated, and carbon monoxide and carbon dioxide gas are generated. The iron ore is gradually reduced to iron by the carbon monoxide gas, thus forming primary reduction ironmaking. During the primary reduction ironmaking process, the gas separation device receives the mixed gas of carbon monoxide and carbon dioxide from the direct reduction ironmaking furnace and separates the carbon monoxide and carbon dioxide. (3) Secondary reduction ironmaking: The material that has undergone primary reduction ironmaking in the direct reduction ironmaking furnace is transferred to the direct reduction ironmaking ladle through a valve. At the same time, the carbon monoxide separated by the gas separation device is transferred to the direct reduction ironmaking ladle through a valve and mixed with the material. The reduction reaction continues using the heat of the carbon monoxide gas and the material itself. The remaining unreduced iron ore in the direct reduction ironmaking ladle is further reduced to iron by the carbon monoxide gas, thus forming secondary reduction ironmaking.

13. The ironmaking method using a direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 12, characterized in that, It also includes the following steps set after the secondary reduction ironmaking in step (3): (4) Transfer and replacement of direct reduction ironmaking ladle: disconnect the carbon monoxide delivery pipeline of the gas separation device from the direct reduction ironmaking ladle, drive the lifting platform on the mobile platform to descend, disconnect the direct reduction ironmaking ladle from the direct reduction ironmaking furnace, and move the direct reduction ironmaking ladle that has completed secondary reduction ironmaking from below the direct reduction ironmaking furnace through the mobile platform; then use the mobile platform with the lifting platform to move the next empty direct reduction ironmaking ladle to below the direct reduction ironmaking furnace and dock it with the direct reduction ironmaking furnace, and connect the carbon monoxide delivery pipeline of the gas separation device to the empty direct reduction ironmaking ladle. (5) Continuous production of direct reduction smelting: Repeat steps (1) to (4) to achieve continuous production of direct reduction iron smelting.

14. The ironmaking method using a direct reduction ironmaking apparatus employing a secondary reduction reaction according to claim 12, characterized in that, The preheating temperature in the iron ore preheating tank is 700-800℃, the reduction reaction temperature in the direct reduction ironmaking furnace is set at 1300℃, and the reduction reaction temperature in the direct reduction ironmaking ladle is not lower than 900℃.

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