A composite fuel burner for hydrogen reduction of copper slag

Abstract

This invention relates to the field of burners and discloses a composite fuel burner for hydrogen reduction of copper slag, comprising: a first sleeve, one end of which is closed and the other end of which is provided with a first air outlet, and a first air inlet on the outer side of the first sleeve; a central tube with a closed end face where it enters the first sleeve, and a plurality of first side air holes on the outer side of the end of the central tube where it enters the first sleeve; a second sleeve with a plurality of second side air holes on the outer side of the end near the first air outlet, and a second air inlet on the outer side of the end of the second sleeve near the first air inlet; a third sleeve with a closed end near the second air inlet, and a third air inlet on the outer side of the end of the third sleeve near the second air inlet, and a second air outlet formed at the end of the third sleeve away from the second air inlet. This invention not only provides heat but also integrates functions such as carbon reduction, material preheating, preliminary reduction, and atmosphere creation, improving the flexibility, compactness, and combustion efficiency of the entire combustion equipment.

Description

Technical Field

[0001] This invention relates to the field of burners and discloses a composite fuel burner for hydrogen reduction of copper slag. Background Technology

[0002] Copper slag contains approximately 40% iron, sometimes as high as 50%, primarily in the form of fir olivine and magnetite (Fe3O4). It requires reduction under additives and high-temperature conditions. Traditional processes mainly use carbon-based reducing agents such as coal or coke powder, which act as both reducing agents in the reaction and provide a high-temperature combustion environment. This method suffers from low reduction and combustion efficiency, accompanied by significant carbon dioxide emissions. Further carbon removal treatment of the flue gas is necessary before discharge, resulting in low overall combustion efficiency and the need for carbon emission control equipment, making it difficult to reduce overall production costs. Therefore, there is an urgent need for a burner that is lower in carbon emissions and produces cleaner, more efficient combustion. Summary of the Invention

[0003] The purpose of this invention is to provide a composite fuel burner for the hydrogen reduction of copper slag, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0004] According to a first aspect of the present invention, a composite fuel burner for hydrogen reduction of copper slag includes: a first sleeve, one end of which is closed and the other end of which is provided with a first air outlet, and a first air inlet provided on the outer side of the first sleeve; a central tube, which enters the first sleeve from the closed end of the first sleeve, the end face of the central tube entering the first sleeve being closed, and a plurality of first side air holes provided on the outer side of the end of the central tube entering the first sleeve; a second sleeve, which is sleeved on the outer side of the first sleeve, the second sleeve being located between the first air outlet and the first air inlet, both ends of the second sleeve being closed, a plurality of second side air holes provided on the outer side of the end of the second sleeve near the first air outlet, and a second air inlet provided on the outer side of the end of the second sleeve near the first air inlet; and a third sleeve, which is sleeved on the outer side of the second sleeve, the end of the third sleeve near the second air inlet being closed, the outer side of the end of the third sleeve near the second air inlet being provided with a third air inlet, and the end of the third sleeve away from the second air inlet extending out of the first sleeve and forming a second air outlet.

[0005] This technical solution has at least the following beneficial effects: The end of the central tube outside the first sleeve is connected to the hydrogen required for the standby flame; the first air inlet on the outside of the first sleeve is connected to the air required for the standby flame; the second air inlet on the outside of the second sleeve is connected to hydrogen for combustion and reduction; and the third air inlet on the outside of the third sleeve is connected to a mixed powder containing copper slag, coal powder, and other materials. The portion of the third sleeve protruding from the first sleeve forms a combustion chamber. After the hydrogen enters the central tube, because the end of the central tube located in the first sleeve is closed, the hydrogen is forced to radially exit from multiple first side vents into the first sleeve within the central tube, where it mixes thoroughly with the air required for the standby flame flowing within the first sleeve. This greatly improves the stability of the central flame, while the hydrogen used for combustion and reduction... The hydrogen gas used in the original process, after entering the second casing, is discharged from multiple second-side vents located on the outer side of the end of the second casing. It mixes with the mixed powder conveyed in the third casing and then enters the combustion chamber, where it is ignited by the central duty flame. In this way, by mixing hydrogen gas, the combustion efficiency of pulverized coal is significantly improved, reducing carbon emissions from the source. Furthermore, the copper slag material is premixed with pulverized coal and directly injected into the combustion chamber. The high-temperature environment of the reducing flame is used to achieve rapid heating and preliminary reduction of the material, shortening the subsequent preheating and reduction time in the kiln. This integrates material preheating and preliminary reduction. In addition, the central hydrogen non-premixed swirl duty flame provides a stable and reliable ignition source and combustion zone for the peripheral composite fuel main flame, achieving staged combustion and broadening the stable operating range of the burner.

[0006] According to some embodiments of the present invention, a first swirl vane is provided on the outer side of the end of the central tube near the first side air hole, and the airflow in the first sleeve passes through the first swirl vane and then through a plurality of the first side air holes.

[0007] According to some embodiments of the present invention, the first swirl blade is detachably connected to the central tube.

[0008] According to some embodiments of the present invention, the included angle between the first swirl blade and the axis of the central tube is between 30 degrees and 60 degrees.

[0009] According to some embodiments of the present invention, a second swirl vane is provided on the outer side of the first sleeve, and the airflow in the third sleeve first passes through a plurality of second side air holes and then passes through the second swirl vane.

[0010] According to some embodiments of the present invention, the second swirl blade and the first sleeve are detachably connected.

[0011] According to some embodiments of the present invention, the included angle between the second swirl blade and the axis of the first sleeve is less than 30 degrees.

[0012] According to some embodiments of the present invention, a purge pipe is provided on the outer side of the third sleeve.

[0013] According to some embodiments of the present invention, an air outlet sleeve is provided on the outer side of the end of the third sleeve near the second air outlet, one end of the air outlet sleeve protrudes from the third sleeve and forms a narrowing section, the inner diameter of the narrowing section gradually decreasing in the direction away from the second air outlet.

[0014] According to some embodiments of the present invention, the angle formed between the extension line of the inner wall of the narrowed section and the axis of the third sleeve is between 30 degrees and 60 degrees.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of the present invention, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.

[0017] Figure 1 This is an overall front view of the present invention.

[0018] Figure 2 yes Figure 1 A schematic diagram of the AA cross-sectional structure.

[0019] Figure 3 This is a schematic cross-sectional view of the present invention on the plane passing through the axis of the central tube and the axis of the third air inlet.

[0020] In the attached diagram: 100-first sleeve, 110-first air outlet, 200-center tube, 210-first side air hole, 300-second sleeve, 310-second side air hole, 320-second air inlet, 400-third sleeve, 410-third air inlet, 420-second air outlet, 500-first swirl vane, 600-second swirl vane, 700-purge pipe, 800-air outlet sleeve, 810-narrowing section. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0025] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0026] In the description of this application, the use of terms such as "one embodiment," "some embodiments," "an example," "some instances," "some embodiments," "illustrative embodiment," "example," "specific example," and "some examples" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0027] Reference Figure 1 and Figure 2According to a first aspect of the present invention, a composite fuel burner for hydrogen reduction of copper slag includes a central tube 200, a first sleeve 100, a second sleeve 300, and a third sleeve 400. One end of the first sleeve 100 is closed, and the other end of the first sleeve 100 has a first air outlet 110. A first air inlet is provided on the outer side of the first sleeve 100. The central tube 200 enters the first sleeve 100 from its closed end, with the end face of the central tube 200 entering the first sleeve 100 closed. A plurality of first side air holes 210 are provided on the outer side of the end of the central tube 200 entering the first sleeve 100. Naturally, there is a gap between the outer side of the central tube 200 and the inner side of the first sleeve 100 for airflow to pass through. The second sleeve 300 is sleeved on the outer side of the first sleeve 100, and the second sleeve 300 is located between the first air outlet 110 and the first air inlet. Between the two ends of the second sleeve 300, multiple second side air holes 310 are provided on the outer side of the end of the second sleeve 300 near the first air outlet 110, and a second air inlet 320 is provided on the outer side of the end of the second sleeve 300 near the first air inlet. Naturally, there is a gap between the outer side of the second sleeve 300 and the inner side of the third sleeve 400 for airflow to pass through. The third sleeve 400 is sleeved on the outer side of the second sleeve 300. The end of the third sleeve 400 near the second air inlet 320 is closed. A third air inlet 410 is provided on the outer side of the end of the third sleeve 400 near the second air inlet 320. The end of the third sleeve 400 away from the second air inlet 320 extends out of the first sleeve 100 and forms a second air outlet 420. Naturally, there is a gap between the inner side of the third sleeve 400 and the outer side of the second sleeve 300 for airflow to pass through.

[0028] As described above, the end of the central tube 200 outside the first sleeve 100 is connected to the hydrogen required for the standby flame. The first air inlet on the outside of the first sleeve 100 is connected to the air required for the standby flame. The second air inlet 320 on the outside of the second sleeve 300 is connected to hydrogen for combustion and reduction. The third air inlet 410 on the outside of the third sleeve 400 is connected to a mixed powder containing materials such as copper slag and coal powder. The part of the third sleeve 400 protruding from the first sleeve 100 forms a combustion chamber. After the hydrogen enters the central tube 200, because the end of the central tube 200 is closed at the first sleeve 100, the hydrogen is forced to be radially ejected from the central tube 200 through multiple first side air holes 210 into the first sleeve 100, where it is fully mixed with the air required for the standby flame flowing in the first sleeve 100, greatly improving the combustion efficiency of the central flame. The stability of the coal slag material is improved by mixing it with the coal powder conveyed in the third sleeve 400. The hydrogen used for combustion and reduction is discharged from multiple second side vents 310 on the outer side of the end of the second sleeve 300 after entering the second sleeve 300. It is then mixed with the mixed powder in the third sleeve 400 and then enters the combustion chamber and is ignited by the central duty flame. In this way, the coal slag material is significantly improved by mixing with the coal powder, reducing carbon emissions from the source. The copper slag material is premixed with the coal powder and then directly injected into the combustion chamber. The high temperature environment of the reducing flame is used to achieve rapid heating and preliminary reduction of the material, shortening the subsequent preheating and reduction time in the kiln. This integrates material preheating and preliminary reduction. Furthermore, the central hydrogen non-premixed swirl duty flame provides a stable and reliable ignition source and combustion zone for the peripheral composite fuel main flame, achieving staged combustion and broadening the stable operating range of the burner.

[0029] In practical applications, such as Figure 3 As shown, the third sleeve 400 is equipped with an air inlet pipe at the position of the third air inlet 410. The air inlet pipe extends obliquely away from the air outlet sleeve 800. In this way, the copper slag material and coal powder are mixed and guided through the air inlet pipe and sent into the third sleeve 400. This effectively reduces the blockage of material at the position of the third air inlet 410 in the third sleeve 400 and improves the overall feeding stability.

[0030] To improve the mixing effect of hydrogen and air required for the central flame, in this embodiment, a first swirl vane 500 is provided on the outer side of the end of the central tube 200 near the first side air hole 210. The airflow in the first sleeve 100 passes through the first swirl vane 500 and then through multiple first side air holes 210. The air transported in the first sleeve 100 forms a swirl after passing through the first swirl vane 500, and mixes more thoroughly with the hydrogen radially ejected from the multiple first side air holes 210, further improving the stability of the central flame. Furthermore, the mixing of hydrogen downstream of the outlet of the first swirl vane 500 helps to avoid the risk of hydrogen combustion backfire.

[0031] To facilitate maintenance of the first swirl vane 500, in this embodiment, the first swirl vane 500 is detachably connected to the central tube 200. The first swirl vane 500 can be fixed to the outside of the central tube 200 by means of threaded connection, screw connection, or snap-fit ​​connection. During operation, the first swirl vane 500 with different blade angles can be replaced as needed, improving the flexibility of use. In practical applications, the first swirl vane 500 includes a first connecting sleeve and multiple first blades arranged circumferentially on the outside of the connecting sleeve. The airflow is guided by the multiple inclined first blades, thereby forming a swirl.

[0032] Furthermore, the angle between the first swirl vane 500 and the axis of the central tube 200 is between 30 and 60 degrees, that is, the angle between the plurality of first vanes disposed on the outside of the first connecting sleeve and the axis of the central tube 200 is between 30 and 60 degrees. Under this inclination range, the first swirl vane 500 can promote the formation of a stronger swirl in the airflow within the first sleeve 100 and ensure the flow rate of the airflow within the first sleeve 100.

[0033] Similarly, to ensure more thorough mixing of the hydrogen used for combustion and reduction with the powder, in this embodiment, a second swirl vane 600 is provided on the outer side of the first sleeve 100. The airflow in the third sleeve 400 first passes through multiple second side air holes 310 and then through the second swirl vane 600. The hydrogen transported in the third sleeve 400 is radially ejected from the multiple second side air holes 310, first mixing with the powder transported in the third sleeve 400, and then passing through the second swirl vane 600. The second swirl vane 600 forms a swirl in the mixed airflow to enter the combustion chamber, thereby improving combustion efficiency. This ensures that the hydrogen and the material are in full and uniform contact in a suspended state, effectively solving the problems of difficult hydrogen diffusion and incomplete reduction in fixed bed or stacked state.

[0034] To facilitate maintenance of the second swirl vane 600, in this embodiment, the second swirl vane 600 is detachably connected to the first sleeve 100. The second swirl vane 600 can be fixed to the outside of the central tube 200 by means of threaded connection, screw connection, or snap-fit ​​connection. During operation, the second swirl vane 600 can be quickly replaced and maintained by disassembling and assembling it, improving the flexibility of use. In practical applications, the second swirl vane 600 includes a second connecting sleeve and multiple second vanes arranged circumferentially on the outside of the connecting sleeve. The airflow is guided by the multiple inclined second vanes, thereby forming a swirl. In addition, the central tube 200 and the first sleeve 100 are also detachably connected, so that the central tube 200 can be easily replaced according to usage needs.

[0035] Furthermore, the angle between the second swirl vane 600 and the axis of the first sleeve 100 is less than 30 degrees. Controlling the tilt angle of the second swirl vane 600 within this range effectively prevents blockage of the mixed powder as it passes through, thus improving the smoothness of the burner's operation.

[0036] To further prevent the mixed powder from clogging the second swirl blade 600, in this embodiment, a purge pipe 700 is provided on the outer side of the third sleeve 400. When it is necessary to clean the second swirl blade 600, the purge pipe 700 can be connected to an external compressed air supply. By introducing compressed air, the second swirl blade 600 can be purged, thereby removing any material that may accumulate on the swirl blade, effectively preventing clogging, and ensuring reliable long-term continuous operation.

[0037] To further improve combustion efficiency, in this embodiment, an outlet sleeve 800 is fitted onto the outer side of the end of the third sleeve 400 near the second outlet 420. One end of the outlet sleeve 800 protrudes from the third sleeve 400 and forms a narrowing section 810. The inner diameter of the narrowing section 810 gradually decreases in the direction away from the second outlet 420. The narrowing section 810 of the outlet sleeve 800 forms a constricted structure, which can slow down the airflow speed through the combustion chamber, thus improving the combustion efficiency inside the combustion chamber. Furthermore, the narrowing section 810 allows for better control of the outlet flow rate and flame pattern.

[0038] Furthermore, the angle formed between the extension line of the inner wall of the narrowing section 810 and the axis of the third sleeve 400 is between 30 and 60 degrees. Controlling the inclination angle of the inner wall of the narrowing section 810 within this range allows for better control of the outlet flow rate and flame pattern, thereby improving combustion stability.

[0039] In practical applications, the central duty flame burns in a lean state with an excess air coefficient of 1 to 1.3, with a power range of 2 to 10 kW, mainly for ignition and stabilization.

[0040] In the mixed powder input to the third casing 400, the copper slag is in 200-mesh particle state, and the additive is calcium oxide or calcium carbonate. When mixing copper slag and additives, the amount of additive is added according to the stoichiometric ratio based on the total amount of materials and the proportion of the fir olivine phase, but the mass ratio of additives should not exceed 15%. When mixing copper slag, additives, and coal powder, the proportion of coal powder should preferably be above 50%, otherwise unstable combustion may easily occur.

[0041] The homogenized powder is fed by an external screw feeder and fed into the third bushing 400 by combustion air. The amount of air is generally slightly less than that required for the complete combustion of pulverized coal and hydrogen as fuel. The excess air coefficient should be between 0.7 and 0.9. The addition of hydrogen helps the fuel burn stably in a reducing atmosphere. The remaining hydrogen and carbon monoxide produced by the incomplete combustion of pulverized coal act as a reducing agent in the flame, rapidly heating and initially reducing the mixture of copper slag and additives. In the hydrogen-coated combustion layer, the amount of hydrogen should not exceed 30% based on its calorific value.

[0042] As described above, this invention integrates copper slag waste, basic fuel, and low-carbon reducing agent into a single system for pretreatment and coordinated injection, achieving simultaneous initiation of heating and reduction reactions in the burner outlet area. This revolutionizes the traditional step-by-step process of rotary kilns, which involves heating first and then reducing. In practical applications, a high-temperature reducing atmosphere can be precisely created and controlled by independently adjusting the hydrogen flow rate and combustion air volume, allowing hydrogen and carbon monoxide produced by incomplete combustion to exert their reducing effect in the flame. Furthermore, a specific scheme is proposed to blend no more than 30% hydrogen into pulverized coal. Utilizing the rapid flame propagation speed of hydrogen, the stable combustion boundary of pulverized coal under a reducing atmosphere is broadened, achieving efficient and low-carbon combustion.

[0043] This invention has the following outstanding advantages:

[0044] 1. Hydrogen-assisted combustion and carbon reduction: By blending hydrogen, the combustion efficiency of pulverized coal is significantly improved, achieving energy conservation and reducing carbon emissions at the source.

[0045] 2. Integrated material preheating and preliminary reduction: Copper slag material is premixed with pulverized coal and then directly injected into the combustion chamber. The high-temperature environment of the reducing flame is used to achieve rapid heating and preliminary reduction of the material, shortening the subsequent preheating and reduction time in the kiln.

[0046] 3. Overcoming the challenge of hydrogen reduction contact: The fuel-material mixing and injection structure enables hydrogen and materials to fully and uniformly contact each other in a suspended state, effectively solving the technical bottleneck of difficult hydrogen diffusion and incomplete reduction in fixed bed or stacked state.

[0047] 4. Staged combustion ensures stability: The central hydrogen non-premixed swirl flame provides a stable and reliable ignition source and ignition zone for the peripheral composite fuel main flame, thus expanding the stable operating range of the burner.

[0048] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A composite fuel burner for hydrogen reduction of copper slag, characterized in that: include: The first sleeve (100) has a closed end and a first air outlet (110) at the other end. A first air inlet is provided on the outside of the first sleeve (100), and the first air inlet on the outside of the first sleeve (100) is connected to the air required for the duty flame. A central tube (200) is inserted into the first sleeve (100) from one of its closed ends. The end face of the central tube (200) inserted into the first sleeve (100) is closed. A plurality of first side vents (210) are provided on the outer side of the end of the central tube (200) inserted into the first sleeve (100). The end of the central tube (200) located outside the first sleeve (100) is connected to the hydrogen gas required for the duty flame. The second sleeve (300) is sleeved on the outside of the first sleeve (100). The second sleeve (300) is located between the first outlet (110) and the first inlet. Both ends of the second sleeve (300) are closed. Multiple second side air holes (310) are provided on the outer side of the end of the second sleeve (300) near the first outlet (110). A second inlet (320) is provided on the outer side of the end of the second sleeve (300) near the first inlet. Hydrogen gas for combustion and reduction is introduced into the second inlet (320) on the outer side of the second sleeve (300). The third sleeve (400) is sleeved on the outside of the second sleeve (300). The end of the third sleeve (400) near the second air inlet (320) is closed. The third air inlet (410) is provided on the outside of the end of the third sleeve (400) near the second air inlet (320). The end of the third sleeve (400) away from the second air inlet (320) extends to protrude from the first sleeve (100) and forms a second air outlet (420). The third air inlet (410) on the outside of the third sleeve (400) is connected to a mixed powder containing copper slag and coal powder. An air inlet pipe is provided at the position of the third air inlet (410) of the third sleeve (400). The air inlet pipe extends obliquely in the direction away from the air outlet sleeve (800).

2. A composite fuel burner for hydrogen reduction of copper slag according to claim 1, characterized in that: The central tube (200) is provided with a first swirl vane (500) on the outer side of the end near the first side air hole (210). The airflow in the first sleeve (100) passes through the first swirl vane (500) and then through multiple first side air holes (210).

3. A composite fuel burner for hydrogen reduction of copper slag according to claim 2, characterized in that: The first swirl vane (500) and the central tube (200) are detachably connected.

4. A composite fuel burner for hydrogen reduction of copper slag according to claim 2, characterized in that: The angle between the first swirl blade (500) and the axis of the central tube (200) is between 30 degrees and 60 degrees.

5. A composite fuel burner for hydrogen reduction of copper slag according to claim 1, characterized in that: The first sleeve (100) is provided with a second swirl vane (600) on the outside. The airflow in the third sleeve (400) first passes through multiple second side air holes (310) and then passes through the second swirl vane (600).

6. A composite fuel burner for hydrogen reduction of copper slag according to claim 5, characterized in that: The second swirl blade (600) is detachably connected to the first sleeve (100).

7. A composite fuel burner for hydrogen reduction of copper slag according to claim 5, characterized in that: The angle between the second swirl blade (600) and the axis of the first sleeve (100) is less than 30 degrees.

8. A composite fuel burner for hydrogen reduction of copper slag according to claim 1, characterized in that: A purge pipe (700) is provided on the outside of the third sleeve (400).

9. A composite fuel burner for hydrogen reduction of copper slag according to claim 1, characterized in that: An air outlet sleeve (800) is fitted on the outer side of the end of the third sleeve (400) near the second air outlet (420). One end of the air outlet sleeve (800) protrudes from the third sleeve (400) and forms a narrowing section (810). The inner diameter of the narrowing section (810) gradually decreases in the direction away from the second air outlet (420).

10. A composite fuel burner for hydrogen reduction of copper slag according to claim 9, characterized in that: The angle between the extension line of the inner wall of the narrowed section (810) and the axis of the third sleeve (400) is between 30 degrees and 60 degrees.

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