Leaching residue desulfurization and iron extraction system

Abstract

The utility model provides a desulfurization and iron extraction system for leaching residues. The system comprises a countercurrent rotary kiln, a waste heat recovery device and a reduction furnace, a feeding port is formed in the feeding end of the countercurrent rotary kiln, a kiln head cover and a fuel gun are arranged at the discharging end of the countercurrent rotary kiln, and the fuel gun penetrates through the kiln head cover and extends into a barrel of the countercurrent rotary kiln; the waste heat recovery device comprises a low-temperature medium channel and a high-temperature material channel, and the upper portion of the high-temperature material channel communicates with the discharging end of the countercurrent rotary kiln through a kiln head cover. A hearth area, a slag layer area and a metal layer area which are distributed up and down are defined in a furnace body of the reduction furnace, the upper portion of the hearth area is communicated with the lower portion of the high-temperature material channel, and a metal discharging opening is formed in the metal layer area. According to the system, coupling of the rotary kiln and the reduction furnace is achieved through the waste heat recovery device, the technological process of conducting desulfurization and iron extraction on the leaching residues can be simplified, the production cost is reduced, full utilization of waste heat is facilitated, and meanwhile the efficiency and effect of conducting desulfurization and iron extraction on the leaching residues are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of metallurgy, in particular to a leaching slag desulfurization and iron extraction system. Background Art

[0002] Leaching slag refers to the solid material left after the valuable components in ore, concentrate, roasted sand or other solid materials are leached with a leaching agent. After the valuable components are extracted from the leaching slag, it is usually treated as solid waste in a stockpile. Taking laterite nickel ore as an example, the pressurized wet leaching process is usually used to extract nickel and cobalt resources from laterite nickel ore. However, this process produces a large amount of leaching slag. Although the leaching slag is rich in iron, the iron in the leaching slag mainly exists in the form of hematite, and the leaching slag has high water and sulfur content and low grade, so it cannot be directly used as an ironmaking raw material. Therefore, it is usually treated in a stockpile, which not only causes a huge waste of resources, but also has extremely high environmental safety risks. If not properly handled, it will become a bottleneck of the pressurized wet leaching process. Utility Model Content

[0003] The utility model aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] In the first aspect of the utility model, a leaching slag desulfurization and iron extraction system is proposed, comprising:

[0005] A countercurrent rotary kiln, wherein a feed port is provided at the feed end of the countercurrent rotary kiln, and the feed port is suitable for supplying leached slag and desulfurization reducing agent to the countercurrent rotary kiln, and a kiln head cover and a fuel gun are provided at the discharge end of the countercurrent rotary kiln, and the fuel gun extends through the kiln head cover into the cylinder of the countercurrent rotary kiln;

[0006] A waste heat recovery device, the waste heat recovery device comprising a low-temperature medium channel and a high-temperature material channel, the upper portion of the high-temperature material channel being connected to the discharge end of the countercurrent rotary kiln through the kiln head cover;

[0007] A reduction furnace, wherein a furnace body of the reduction furnace defines a furnace zone, a slag layer zone and a metal layer zone which are distributed up and down, the upper part of the furnace zone is connected with the lower part of the high-temperature material channel, and the metal layer zone is provided with a metal discharge port.

[0008] The leaching slag desulfurization and iron extraction system of the first aspect of the utility model has at least the following beneficial effects: the leaching slag can be subjected to high-temperature roasting and desulfurization by a rotary kiln, and the roasted sand obtained by the high-temperature roasting and desulfurization can be directly dropped into a reduction furnace through a high-temperature material channel of a waste heat recovery device, so that the roasted sand undergoes a reduction reaction in the reduction furnace to obtain molten iron and slag. On the one hand, the combustion tail gas (i.e., raw coal gas) of the reduction furnace can be used as a fuel and heat source for the reduction and desulfurization of the leaching slag, and the raw coal gas (usually with a temperature of 1650°C-1800°C) generated in the reduction furnace is cooled through a high-temperature material channel in the waste heat recovery device and then supplied from the discharge end of the rotary kiln. To the rotary kiln, at the same time, oxygen-rich air is blown into the raw coal gas through the combustion gun to maintain the heat required for roasting in the rotary kiln; on the other hand, the high-temperature material channel and the heat of the raw coal gas can be used to pre-reduce the roasted sand during the falling process, and the roasted sand can be partially reduced and melted during the falling process into the reduction furnace, thereby not only improving the efficiency and effect of the reduction reaction of the roasted sand in the reduction furnace, but also eliminating the need for pre-treatment processes such as cooling, transporting and reheating the roasted sand for iron extraction. In addition, the primary coal gas obtained by the reduction reaction of the roasted sand in the reduction furnace can also be used to supplement the heat of the molten pool after secondary combustion to maintain thermal balance. Therefore, the system realizes the coupling of the rotary kiln and the reduction furnace by utilizing the waste heat recovery device, which not only simplifies the process flow of desulfurization and iron extraction of the leaching slag and reduces the production cost, but also helps to fully utilize the waste heat, while improving the efficiency and effect of desulfurization and iron extraction of the leaching slag.

[0009] In addition, the leaching slag desulfurization and iron extraction system according to the first aspect of the utility model may also have the following additional technical features:

[0010] Optionally, the kiln head hood is provided with a gas vent.

[0011] Optionally, the feed end of the countercurrent rotary kiln is provided with a kiln tail hood, the kiln tail hood is provided with a smoke outlet and a feed pipe, one end of the feed pipe is provided with the feed port, and the other end passes through the kiln tail hood and extends into the cylinder of the countercurrent rotary kiln.

[0012] Optionally, the low-temperature medium channel and the high-temperature material channel are arranged at intervals.

[0013] Optionally, the waste heat recovery device comprises a shell, a low-temperature medium channel is provided in the shell, and the shell encloses the high-temperature material channel.

[0014] Optionally, the waste heat recovery device is a waste heat boiler, and the furnace wall of the waste heat boiler is a membrane wall.

[0015] Optionally, the furnace body of the reduction furnace includes a furnace bottom, a furnace wall and a furnace top, the furnace bottom, the furnace wall and the furnace top enclose a furnace space, the furnace space includes the furnace area, the slag layer area and the metal layer area, and the upper part of the furnace area is connected to the lower part of the high-temperature material channel through the furnace top.

[0016] Optionally, the furnace top and the bottom of the waste heat recovery device are connected by a flexible connection to achieve communication between the upper part of the furnace zone and the lower part of the high-temperature material channel.

[0017] Optionally, the reduction furnace further comprises a furnace frame, and the furnace body is installed on the furnace frame.

[0018] Optionally, the furnace top is provided with a lump coal inlet and / or a flux inlet.

[0019] Optionally, the reduction furnace further comprises: a submerged reduction lance, a submerged combustion lance and a secondary combustion lance, wherein the submerged reduction lance and the submerged combustion lance independently penetrate the furnace wall and extend into the slag layer area, and the secondary combustion lance penetrates the furnace wall and extends into the furnace chamber area.

[0020] Optionally, the reduction furnace further comprises: a primary coal gas outlet, wherein the primary coal gas outlet is arranged above the slag layer area and close to the slag layer area.

[0021] Optionally, the submerged reduction lances and the submerged combustion lances are staggered at the same height of the reduction furnace.

[0022] Optionally, the furnace wall is provided with a siphon slag discharge port, and the siphon slag discharge port is located in the slag layer area.

[0023] Optionally, the furnace wall is provided with a foamed slag overflow port, and the foamed slag overflow port is located in the furnace area.

[0024] Optionally, the siphon slag discharge port is arranged in an area of ​​the furnace wall that is 200 mm to 300 mm higher than the metal layer area.

[0025] Optionally, the vertical height between the foamed slag overflow port and the furnace top is 0.8m to 1.2m. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0027] Figure 1 The utility model is a schematic structural diagram of a leaching slag desulfurization and iron extraction system according to an embodiment of the utility model.

[0028] Figure 2It is a structural schematic diagram of a leaching slag desulfurization and iron extraction system according to another embodiment of the utility model.

[0029] Reference numerals:

[0030] 10-countercurrent rotary kiln; 11-feeding port; 12-kiln head cover; 13-fuel gun; 14-gas release port 14; 15-kiln tail cover; 16-smoke outlet; 17-feeding pipe; 20-waste heat recovery device; 21-high-temperature material channel; 30-reduction furnace; 31-furnace area; 32-slag layer area; 33-metal layer area; 34-furnace frame; 35-submerged reduction spray gun; 36-submerged combustion spray gun; 37-secondary combustion gun; 38-foam slag overflow port. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0032] In the first aspect of the utility model, a leaching slag desulfurization and iron extraction system is proposed, comprising: a countercurrent rotary kiln 10, a waste heat recovery device 20 and a reduction furnace 30. Among them, the feed end of the countercurrent rotary kiln 10 is provided with a feed port 11, and the feed port 11 is suitable for supplying leaching slag and desulfurization reducing agent to the countercurrent rotary kiln 10, and the discharge end of the countercurrent rotary kiln 10 is provided with a kiln head cover 12 and a fuel gun 13, and the fuel gun 13 extends into the cylinder of the countercurrent rotary kiln 10 through the kiln head cover 12; the waste heat recovery device 20 includes a low-temperature medium channel (not shown) and a high-temperature material channel 21, and the upper part of the high-temperature material channel 21 is connected to the discharge end of the countercurrent rotary kiln 10 through the kiln head cover 12; the furnace body of the reduction furnace 30 defines a furnace area 31, a slag layer area 32 and a metal layer area 33 distributed up and down, and the upper part of the furnace area 31 is connected to the lower part of the high-temperature material channel 21, and the metal layer area 33 is provided with a metal discharge port (not shown).

[0033] The leaching slag desulfurization and iron extraction system of the first aspect of the utility model has at least the following beneficial effects: the leaching slag can be subjected to high-temperature roasting and desulfurization by a rotary kiln, and the roasted sand obtained by the high-temperature roasting and desulfurization can be directly dropped into a reduction furnace through a high-temperature material channel of a waste heat recovery device, so that the roasted sand undergoes a reduction reaction in the reduction furnace to obtain molten iron and slag. On the one hand, the combustion tail gas (i.e., raw coal gas) of the reduction furnace can be used as a fuel and heat source for the reduction and desulfurization of the leaching slag, and the raw coal gas (usually with a temperature of 1650°C-1800°C) generated in the reduction furnace is cooled through a high-temperature material channel in the waste heat recovery device and then supplied from the discharge end of the rotary kiln. To the rotary kiln, at the same time, oxygen-rich air is blown into the raw coal gas through the combustion gun to maintain the heat required for roasting in the rotary kiln; on the other hand, the high-temperature material channel and the heat of the raw coal gas can be used to pre-reduce the roasted sand during the falling process, and the roasted sand can be partially reduced and melted during the falling process into the reduction furnace, thereby not only improving the efficiency and effect of the reduction reaction of the roasted sand in the reduction furnace, but also eliminating the need for pre-treatment processes such as cooling, transporting and reheating the roasted sand for iron extraction. In addition, the primary coal gas obtained by the reduction reaction of the roasted sand in the reduction furnace can also be used to supplement the heat of the molten pool after secondary combustion to maintain thermal balance. Therefore, the system realizes the coupling of the rotary kiln and the reduction furnace by utilizing the waste heat recovery device, which not only simplifies the process flow of desulfurization and iron extraction of the leaching slag and reduces the production cost, but also helps to fully utilize the waste heat, while improving the efficiency and effect of desulfurization and iron extraction of the leaching slag.

[0034] Reference below Figures 1-2 The leaching slag desulfurization and iron extraction system of the above embodiment of the utility model is described in detail.

[0035] According to the embodiments of the utility model, the leached slag and the reducing agent used for desulfurization of the leached slag can be mixed and granulated to obtain leached slag pellets, which are then dried and preheated to remove crystallization water and then supplied to a countercurrent rotary kiln for high-temperature roasting and desulfurization at a temperature of about 1100°C-1200°C to obtain roasted sand and high-temperature flue gas (about 850°C-1050°C). The high-temperature flue gas can be used for acid production after waste heat recovery. When high-temperature roasted sand is supplied to the reduction furnace to react with the reducing agent to prepare molten iron, the primary coal gas obtained by the reduction reaction can be used to supplement the heat of the molten pool after secondary combustion to maintain the thermal balance in the reduction furnace. Due to the limitation of the secondary combustion rate of the primary coal gas (usually 0.4-0.7), the flue gas discharged from the top of the furnace (i.e., combustion tail gas, also called raw coal gas, about 1650-1800°C) contains more combustible gas, which can be cooled to about 1200°C by the waste heat recovery device and enter the rotary kiln as the fuel and heat source for the reduction and desulfurization of the leached slag pellets. In addition, the raw coal gas can also perform contact heat exchange and pre-reduction on the falling roasted sand during the process of rising to the rotary kiln, so that the leached slag pellets can be partially reduced and melted.

[0036] In some embodiments, Figure 2 As shown, the kiln head cover 12 may be provided with a gas release port 14. The gas release port may be used to discharge excess gas.

[0037] In some embodiments, Figure 2 As shown, the feeding end of the countercurrent rotary kiln can be provided with a kiln tail cover 15, and the kiln tail cover 15 can be provided with a smoke outlet 16 and a feed pipe 17. One end of the feed pipe 17 is provided with a feed port 11, and the other end can pass through the kiln tail cover 15 and extend into the cylinder of the countercurrent rotary kiln 10. This is not only conducive to further reducing the heat and airflow loss in the kiln, maintaining the stability of the temperature field in the kiln, but also convenient for feeding. Optionally, the smoke outlet 16 can be connected to a heat exchange device and a purification device in sequence. The heat exchange device is suitable for cooling the high-temperature smoke discharged from the rotary kiln to realize the utilization of waste heat; the purification device is suitable for deacidifying the smoke after heat exchange, and can further preferably include dust removal.

[0038] In some embodiments, reference Figure 1 or Figure 2 It is understood that the countercurrent rotary kiln can also meet at least one of the following conditions: the inner lining of the cylinder of the countercurrent rotary kiln can be a heat-resistant material; the horizontal inclination angle of the cylinder of the countercurrent rotary kiln can be 1°-5°; the cylinder rotation speed of the countercurrent rotary kiln can be 0.5r / min-5r / min; the kiln length of the countercurrent rotary kiln can be 30m-45m; the residence time of the leached slag in the kiln can be 30min-60min; the air flow velocity in the countercurrent rotary kiln can be 5m / s-8m / s.

[0039] In some embodiments, the low-temperature medium channel and the high-temperature material channel of the waste heat recovery device 20 may be spaced apart, thereby preventing the low-temperature medium and the high-temperature material from directly contacting each other, thereby achieving indirect heat exchange.

[0040] In some embodiments, the waste heat recovery device 20 may include a shell (not shown), a low-temperature medium channel may be provided in the shell, and the shell may enclose a high-temperature material channel 21. This may further facilitate the smooth flow of the high-temperature material channel and achieve smooth transmission of high-temperature roasted sand and raw coal gas between the rotary kiln and the reduction furnace.

[0041] In some embodiments, the specific type of the waste heat recovery device 20 is not particularly limited, and those skilled in the art can flexibly select it according to actual needs. Exemplarily, the waste heat recovery device 20 can be a waste heat boiler, and the furnace wall of the waste heat boiler 20 can be a membrane wall. Further, the waste heat recovery device 20 can be a vertical waste heat boiler. Further, in the high-temperature material channel, the air flow velocity can be 5m / s-10m / s.

[0042] In some embodiments, reference Figure 1 or Figure 2 It is understood that the furnace body of the reduction furnace 30 may include a furnace bottom, a furnace wall and a furnace top, and the furnace bottom, the furnace wall and the furnace top may enclose a furnace space, and the furnace space includes a furnace area 31, a slag layer area 32 and a metal layer area 33, and the upper part of the furnace area 31 may be connected to the lower part of the high-temperature material channel 21 through the furnace top. Exemplarily, the furnace top of the reduction furnace may be provided with a smoke exhaust port, and the reduction furnace may be connected to the lower part of the high-temperature material channel 21 through the smoke exhaust port.

[0043] In some embodiments, the top of the reduction furnace 30 and the bottom of the waste heat recovery device 20 can be connected by a flexible connection to realize the communication between the upper part of the furnace area 31 and the lower part of the high-temperature material channel 21. This is beneficial to reduce the stress at the connection between the reduction furnace and the waste heat recovery device, and also to take into account the sealing effect of the connection, thereby reducing the loss of raw coal gas, roasted sand and heat.

[0044] In some embodiments, reference Figure 2 It is understood that the reduction furnace may further include a furnace frame 34 on which the furnace body may be mounted.

[0045] In some embodiments, the roof of the reduction furnace may be provided with a lump coal inlet (not shown) and / or a flux inlet (not shown). In actual operation, the reducing agent may be sprayed into the slag layer through a reduction spray gun or added through the roof. When the reducing agent (such as lump coal) is added through the lump coal inlet, the particle size of the lump coal may be 30 mm to 80 mm. In addition, the flux may be added alone or together with the lump coal after granulation. Optionally, the lump coal and the flux may share a common inlet.

[0046] In some embodiments, reference Figure 2 It is understood that the reduction furnace 20 may also include: a submerged reduction lance 35, a submerged combustion lance 36 and a secondary combustion lance 37, wherein the submerged reduction lance 35 and the submerged combustion lance 36 independently pass through the furnace wall and extend into the slag layer area 32, and the secondary combustion lance 37 passes through the furnace wall and extends into the furnace area 31. Among them, the submerged reduction lance 35 is suitable for injecting a reducing agent, such as reducing gas and / or pulverized coal, into the slag layer area; the submerged combustion lance is suitable for injecting combustion-supporting air and fuel into the slag layer (when the amount of coal gas is insufficient) to supplement the heat consumed by the reduction reaction; the secondary combustion lance is suitable for supplying combustion-supporting air into the furnace, so that the primary coal gas generated by the reduction reaction is burned to supplement the heat of the molten pool.

[0047] In some embodiments, the submerged reduction lances 35 and the submerged combustion lances 36 may be arranged alternately at the same height of the reduction furnace 20. Optionally, the reduction furnace 20 may be provided with a plurality of submerged reduction lances 35 and a plurality of submerged combustion lances 36, and the plurality of submerged reduction lances 35 and a plurality of submerged combustion lances 36 may be arranged alternately and spaced along the circumferential direction of the reduction furnace 20 at the same height of the reduction furnace 20. Optionally, when the amount of coal gas is insufficient, when the submerged combustion lances 36 are used to inject combustion-supporting air and fuel into the slag layer, the combustion-supporting air may be oxygen-enriched combustion-supporting air, and the oxygen-enriched volume concentration in the oxygen-enriched combustion-supporting air is 40% to 80%. Further, the combustion oxygen excess coefficient may be controlled to be 0.95-1.05, and the flame length may be 10m-20m.

[0048] In some embodiments, the reduction furnace 20 may be provided with a plurality of secondary combustion guns 37 , and the plurality of secondary combustion guns 37 may be arranged at intervals along the circumferential direction of the reduction furnace 20 .

[0049] In some embodiments, the reduction furnace may further include: a primary gas outlet (not shown), which may be higher than the slag layer area 32 and disposed close to the slag layer area 32. The primary gas near the slag layer area has a higher purity, and when the amount of gas in the furnace is large, part of the primary gas may be discharged and directly supplied as fuel.

[0050] In some embodiments, the furnace wall of the reduction furnace may be provided with a siphon slag discharge port (not shown), which may be located in the slag layer area. Further, the siphon slag discharge port may be located in an area of ​​the furnace wall 200 mm to 300 mm higher than the metal layer area.

[0051] In some embodiments, reference Figure 2 It is understood that the furnace wall of the reduction furnace may be provided with a foam slag overflow port 38, and the foam slag overflow port 38 is located in the furnace area 31. Providing the foam slag overflow port can prevent the foam slag from entering the waste heat recovery device. Further, the vertical height between the foam slag overflow port and the furnace top can be 0.8m to 1.2m. Exemplarily, the furnace area height of the reduction furnace can be 6m-7m, and the foam slag overflow port can be provided 1m below the furnace top.

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0053] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A leaching slag desulfurization and iron extraction system, characterized in that: include: A countercurrent rotary kiln, wherein a feed port is provided at the feed end of the countercurrent rotary kiln, and the feed port is suitable for supplying leached slag and desulfurization reducing agent to the countercurrent rotary kiln, and a kiln head cover and a fuel gun are provided at the discharge end of the countercurrent rotary kiln, and the fuel gun extends through the kiln head cover into the cylinder of the countercurrent rotary kiln; A waste heat recovery device, the waste heat recovery device comprising a low-temperature medium channel and a high-temperature material channel, the upper portion of the high-temperature material channel being connected to the discharge end of the countercurrent rotary kiln through the kiln head cover; A reduction furnace, wherein a furnace body of the reduction furnace defines a furnace zone, a slag layer zone and a metal layer zone which are distributed up and down, the upper part of the furnace zone is connected with the lower part of the high-temperature material channel, and the metal layer zone is provided with a metal discharge port.

2. The leaching residue desulfurization and iron extraction system according to claim 1, characterized in that: The kiln head hood is provided with a gas release port; and / or, The counter-current rotary kiln is provided with a kiln tail hood at the feeding end thereof, the kiln tail hood is provided with a smoke outlet and a feeding pipe, one end of the feeding pipe is provided with the feeding port, and the other end of the feeding pipe passes through the kiln tail hood and extends into the cylinder of the counter-current rotary kiln; and / or, The low-temperature medium channel and the high-temperature material channel are arranged at intervals.

3. The leaching residue desulfurization and iron extraction system according to claim 1, characterized in that: The waste heat recovery device comprises a shell, a low-temperature medium channel is arranged in the shell, and the shell encloses the high-temperature material channel.

4. The leaching residue desulfurization and iron extraction system according to claim 1, characterized in that: The waste heat recovery device is a waste heat boiler, and the furnace wall of the waste heat boiler is a membrane wall.

5. The leaching residue desulfurization and iron extraction system according to any one of claims 1 to 4, characterized in that: The furnace body of the reduction furnace includes a furnace bottom, a furnace wall and a furnace top. The furnace bottom, the furnace wall and the furnace top enclose a furnace space. The furnace space includes the furnace area, the slag layer area and the metal layer area. The upper part of the furnace area is connected to the lower part of the high-temperature material channel through the furnace top.

6. The leaching residue desulfurization and iron extraction system according to claim 5, characterized in that: The furnace top and the bottom of the waste heat recovery device are connected by a flexible connection to achieve communication between the upper part of the furnace zone and the lower part of the high-temperature material channel; and / or, The reduction furnace further comprises a furnace frame, and the furnace body is mounted on the furnace frame.

7. The leaching residue desulfurization and iron extraction system according to claim 5, characterized in that: The furnace top is provided with a lump coal inlet and / or a flux inlet; and / or, The reduction furnace further comprises: a submerged reduction lance, a submerged combustion lance and a secondary combustion lance, wherein the submerged reduction lance and the submerged combustion lance independently pass through the furnace wall and extend into the slag layer area, and the secondary combustion lance passes through the furnace wall and extends into the furnace area; and / or, The reduction furnace further comprises: a primary coal gas outlet, and the primary coal gas outlet is arranged higher than the slag layer area and close to the slag layer area.

8. The leaching residue desulfurization and iron extraction system according to claim 7, characterized in that: The submerged reduction lances and the submerged combustion lances are arranged alternately at the same height of the reduction furnace.

9. The leaching residue desulfurization and iron extraction system according to claim 5, characterized in that: The furnace wall is provided with a siphon slag discharge port, and the siphon slag discharge port is located in the slag layer area; and / or, The furnace wall is provided with a foam slag overflow port, and the foam slag overflow port is located in the furnace area.

10. The leaching residue desulfurization and iron extraction system according to claim 9, characterized in that: The siphon slag discharge port is arranged in the area of ​​the furnace wall 200 mm to 300 mm higher than the metal layer area; and / or, The vertical height between the foamed slag overflow port and the furnace top is 0.8m to 1.2m.

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