System for producing iron ore concentrate and co-producing sulfuric acid through limonite flue gas desulfurization

Abstract

The utility model discloses a system for producing iron ore concentrate and co-producing sulfuric acid through limonite flue gas desulfurization, which comprises a desulfurization tower, a desulfurization liquid circulating pump, a silicon slag filter, a concentration crystallizer, a centrifugal machine, a rotary kiln, a sulfuric acid absorption tower and a sulfuric acid absorption circulating pump, by adopting the system disclosed by the utility model, the process of producing iron ore concentrate and co-producing sulfuric acid through limonite flue gas desulfurization is realized, the iron oxide of the limonite is used for replacing the traditional limestone flue gas desulfurization, the production cost is reduced, the production efficiency is improved, and the production cost is reduced. Meanwhile, sulfur dioxide in the flue gas is used for producing sulfuric acid, and iron oxide in the limonite is enriched for producing iron ore concentrate.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment, in particular to a system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas. Background Art

[0002] As an iron-rich ore, limonite inevitably produces a large amount of sulfur trioxide flue gas during its mining and smelting process due to the high sulfur characteristics of the ore itself.

[0003] Most traditional flue gas treatment methods have the problem of resource waste. On the one hand, some chemicals or materials used in the treatment process may not be completely recycled and reused, resulting in increased resource consumption; on the other hand, if the by-products or waste generated by the treatment are not properly disposed of, they may also cause secondary pollution to the environment.

[0004] The above two industries have problems such as high operating costs, repeated and large investments, land occupation, secondary pollution, and environmental impact.

[0005] Through certain innovative designs, several processes are combined and applied to achieve the desulfurization of limonite flue gas to produce iron concentrate and sulfuric acid. Utility Model Content

[0006] The utility model provides a system for producing iron concentrate and co-producing sulfuric acid by desulfurizing limonite flue gas, which solves the existing problems.

[0007] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas, comprising a desulfurization tower, a desulfurization liquid circulation pump, a silicon slag filter, a concentration crystallizer, a centrifuge, a rotary kiln, a sulfuric acid absorption tower and a sulfuric acid absorption circulation pump, wherein the desulfurization tower, the desulfurization liquid circulation pump, the silicon slag filter, the rotary kiln, the sulfuric acid absorption tower and the sulfuric acid absorption circulation pump are sequentially connected through pipelines, the silicon slag filter (3) is used to filter the desulfurization slurry to obtain the silicon slag filter cake and the ferric sulfate filtrate; the concentration crystallizer (4) is used to concentrate the ferric sulfate solution and the ferric sulfate crystallization; a centrifuge (5) for separating ferric sulfate crystals and ferric sulfate mother liquor; a rotary kiln (6) for oxidizing and decomposing ferric sulfate to produce iron concentrate and sulfur trioxide flue gas; a sulfuric acid absorption tower (7) for absorbing sulfur trioxide in the flue gas with sulfuric acid to produce sulfuric acid; a sulfuric acid absorption circulation pump (8) for pressurized sulfuric acid transportation; a treatment box is connected to one side of the sulfuric acid absorption tower, a filter plate is connected inside the treatment box, and is used for treating and dusting sulfur trioxide gas; a double-layer spray structure is provided inside the sulfuric acid absorption tower, and a circulating spray structure is connected to one side of the lower end of the sulfuric acid absorption tower.

[0008] Preferably, a long plate is connected to the lower end of the sulfuric acid absorption tower, and springs are connected to the four corners of the lower end of the long plate. A damper is provided inside the spring, and the lower end of the spring is connected to a vertical cylinder.

[0009] Preferably, a vertical plate is connected to the bottom of the treatment box, and a recovery box is connected to the lower end of the inside of the treatment box. A first transfer pipe is connected to the upper end of one side of the treatment box, and a second transfer pipe is connected to the other side of the first transfer pipe, and one end of the second transfer pipe is connected to the sulfuric acid absorption tower.

[0010] Preferably, a solution placement area is provided at the lower end of the interior of the sulfuric acid absorption tower, and two third transfer pipes are connected to one end of the outside of the sulfuric acid absorption tower near the solution placement area. One end of each of the two third transfer pipes is connected to a water pump, and one end of the water pump is connected to a fourth transfer pipe.

[0011] Preferably, one end of each of the fourth transmission tubes is connected to a fifth transmission tube via a flange ring, and the other side of each of the fifth transmission tubes is connected to a plurality of water pipes at equal intervals, and the lower ends of the water pipes are connected to a plurality of nozzles.

[0012] Preferably, a buffer plate is spaced apart below the nozzle, and a plurality of through holes are formed on the buffer plate.

[0013] Preferably, a demisting plate is connected to the upper end of the interior of the sulfuric acid absorption tower, and an exhaust pipe is connected to the middle of the upper end of the sulfuric acid absorption tower.

[0014] Preferably, a concentrating crystallizer and a centrifuge are provided between the silicon slag filter and the rotary kiln, and the mother liquor separated by the centrifuge is returned to the concentrating crystallizer through a pipeline.

[0015] Preferably, the concentrating crystallizer comprises a barrel, a rotating rod is connected to the inside of the barrel, and two stirring rods are respectively provided on the upper and lower sides of the rotating rod, and the upper end of the rotating rod is connected to a motor.

[0016] Preferably, the outer wall of the barrel is connected to a heat-conducting ring plate, and a plurality of heaters are connected at equal intervals inside the heat-conducting ring plate. A protective cover is provided on the outside of the barrel, and an electric valve is connected to the lower end of the barrel.

[0017] The beneficial effects of the utility model are as follows: the mining system is applied to realize the process of desulfurizing limonite flue gas to produce iron concentrate and co-producing sulfuric acid, and the iron oxide in limonite is used to replace the traditional limestone flue gas desulfurization, which reduces the cost of flue gas desulfurization and improves the desulfurization efficiency. At the same time, sulfuric acid is produced from sulfur dioxide in the flue gas, and the iron oxide in the limonite is enriched to produce iron concentrate. There is no desulfurization gypsum and no secondary pollution is generated. It has good economic and environmental benefits, and there is no need to mine limestone for flue gas desulfurization, which reduces the impact on the environment. The flue gas desulfurization and iron ore beneficiation are combined to solve the problems of high operating costs, repeated and large investments, land occupation, secondary pollution, and environmental impact in these two industries.

[0018] The sulfur trioxide gas is discharged into the sulfuric acid absorption tower, and the water pump is started to transfer the treated solution to the water pipe and spray the flue gas through the nozzle. The flue gas is buffered by the buffer plate below, so that the flue gas is fully in contact with the sulfuric acid solution, and the SO2 in the flue gas reacts chemically with the sprayed sulfuric acid solution to produce sulfuric acid, realizing the comprehensive utilization of resources. The demister plate at the top prevents sulfuric acid droplets from being discharged with the flue gas, so as to improve the cleanliness of the exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a system schematic diagram of the present utility model.

[0020] Figure 2 This is a schematic diagram of the sulfuric acid absorption tower of the present invention.

[0021] Figure 3 This is a schematic diagram of a processing box of the present utility model.

[0022] Figure 4 This is a schematic diagram of the interior of the sulfuric acid absorption tower of the present invention.

[0023] Figure 5 This is a cross-sectional view of the sulfuric acid absorption tower of the present invention.

[0024] Figure 6 This is a schematic diagram of a concentration crystallizer of the present utility model.

[0025] Numbers in the figure: 1, desulfurization tower; 2, desulfurization liquid circulation pump; 3, silicon slag filter; 4, concentration crystallizer; 401, drum; 402, rotating rod; 403, stirring rod; 404, motor; 405, heat conduction ring plate; 406, heater; 407, protective cover; 408, electric valve; 5, centrifuge; 6, rotary kiln; 7, sulfuric acid absorption tower; 701, treatment box; 702, filter plate; 703, vertical plate; 7 04. Recovery box; 705. First transfer pipe; 706. Second transfer pipe; 707. Solution placement area; 708. Third transfer pipe; 709. Water pump; 710. Fourth transfer pipe; 711. Fifth transfer pipe; 712. Water pipe; 713. Nozzle; 714. Buffer plate; 715. Demisting plate; 716. Exhaust pipe; 8. Sulfuric acid absorption circulation pump; 9. Long board; 901. Spring; 902. Damper; 903. Vertical cylinder. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Reference Figures 1-6 A system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas, comprising a desulfurization tower 1, a desulfurization liquid circulation pump 2, a silicon slag filter 3, a concentrating crystallizer 4, a centrifuge 5, a rotary kiln 6, a sulfuric acid absorption tower 7 and a sulfuric acid absorption circulation pump 8, wherein the desulfurization tower 1, the desulfurization liquid circulation pump 2, the silicon slag filter 3, the rotary kiln 6, the sulfuric acid absorption tower 7 and the sulfuric acid absorption circulation pump 8 are sequentially connected through pipelines, the silicon slag filter 3 is used to filter the desulfurization slurry to obtain silicon slag filter cake and ferric sulfate filtrate; the concentrating crystallizer 4 is used to concentrate the ferric sulfate solution and crystallize the ferric sulfate; the centrifuge 5 The core machine 5 is used to separate ferric sulfate crystals and ferric sulfate mother liquor; the rotary kiln 6 is used to oxidize and decompose ferric sulfate to produce iron concentrate and sulfur trioxide flue gas; the sulfuric acid absorption tower 7 is used to absorb sulfur trioxide in the flue gas with sulfuric acid to produce sulfuric acid; the sulfuric acid absorption circulation pump 8, one side of the sulfuric acid absorption tower 7 is connected to a treatment box 701, the inside of the treatment box 701 is connected to a filter plate 702 for treating and reducing dust on the sulfur trioxide gas, the inside of the sulfuric acid absorption tower 7 is provided with a double-layer spray structure, and the lower end of the sulfuric acid absorption tower 7 is connected to a circulating spray structure.

[0028] Reference Figure 2 The lower end of the sulfuric acid absorption tower 7 is connected to a long plate 9, and the four corners of the lower end of the long plate 9 are connected to springs 901. A damper 902 is provided inside the spring 901, and the lower end of the spring 901 is connected to a vertical cylinder 903. The device is supported by the long plate 9, and the spring 901 and damper 902 below make the device more stable.

[0029] Reference Figure 3 A vertical plate 703 is connected to the bottom of the treatment box 701, and a recovery box 704 is connected to the lower end of the treatment box 701. A first transfer pipe 705 is connected to the upper end of one side of the treatment box 701, and a second transfer pipe 706 is connected to the other side of the first transfer pipe 705. One end of the second transfer pipe 706 is connected to the sulfuric acid absorption tower 7. Before the sulfur trioxide flue gas is discharged to the sulfuric acid absorption tower 7, it first enters the treatment box 701 through the first transfer pipe 705 and cooperates with the internal filter plate 702 for dust reduction treatment, and then is discharged to the sulfuric acid absorption tower 7 through the second transfer pipe 706.

[0030] Reference Figure 4 , Figure 5 The lower end of the sulfuric acid absorption tower 7 is provided with a solution placement area 707. The outer side of the sulfuric acid absorption tower 7 is connected to one end of the solution placement area 707 with two third transfer pipes 708. One end of each of the two third transfer pipes 708 is connected to a water pump 709. One end of the water pump 709 is connected to a fourth transfer pipe 710. One end of each of the fourth transfer pipes 710 is connected to a fifth transfer pipe 711 through a flange ring. The other side of the fifth transfer pipe 711 is connected to multiple water pipes 712 at equal intervals. The water pipe 71 A plurality of nozzles 713 are connected to the lower end of the sulfuric acid absorption tower 7. Buffer plates 714 are spaced apart below the nozzles 713, and the buffer plates 714 are provided with a plurality of through holes. A demister plate 715 is connected to the upper end of the sulfuric acid absorption tower 7, and an exhaust pipe 716 is connected to the middle of the upper end of the sulfuric acid absorption tower 7. After the sulfur trioxide flue gas is discharged into the sulfuric acid absorption tower 7, it is sprayed by the nozzles 713, and the buffer plates 714 below block the flue gas, so that the flue gas is fully in contact with the treatment solution to react.

[0031] refer to Figure 6 A concentrating crystallizer 4 and a centrifuge 5 are provided between the silicon slag filter 3 and the rotary kiln 6. The mother liquor separated by the centrifuge 5 is returned to the concentrating crystallizer 4 through a pipeline (reference Figure 1 ), the concentrating crystallizer 4 includes a drum 401, a rotating rod 402 connected to the inside of the drum 401, and two stirring rods 403 are respectively provided on the upper and lower sides of the rotating rod 402. The upper end of the rotating rod 402 is connected to a motor 404. A heat-conducting ring plate 405 is connected to the outer wall of the drum 401, and multiple heaters 406 are evenly spaced and connected to the inner side of the heat-conducting ring plate 405. A protective cover 407 is provided on the outside of the drum 401, and an electric valve 408 is connected to the lower end of the drum 401. When the heater 406 is turned on, heat is transferred to the inside of the drum 401 through the heat-conducting ring plate 405. The rotating rod 402 rotates and drives the stirring rod 403 to rotate, stirring the ferric sulfate solution in the drum 401. The heat transferred by the heat-conducting ring plate 405 continuously evaporates and produces crystals. The crystals are transferred to the centrifuge 5 by controlling the opening and closing of the electric valve 408. The key concentrated crystallization is achieved, and the ferric sulfate flows into the rotary kiln, achieving the output of the iron ore concentrate.

[0032] Working principle: the raw material limonite solution and flue gas enter the desulfurization tower 1, and in the desulfurization tower 1, sulfur dioxide reacts with iron oxide in the limonite to form ferric sulfite, which is further oxidized to form ferric sulfate. The ferric sulfate solution enters the silicon slag filter 3 through the desulfurization liquid circulation pump 2 for filtration. The filter cake obtained by filtration is silicon slag, and the filtrate obtained by filtration is ferric sulfate solution. The ferric sulfate solution enters the concentration crystallizer 4, and in the concentration crystallizer 4, the ferric sulfate solution is concentrated and crystallized to obtain a ferric sulfate solid-liquid mixture; the ferric sulfate solid-liquid mixture enters the centrifuge 5 for separation, and the separated solid is ferric sulfate crystals, and the separated liquid is the mother liquor and returns to the concentration crystallizer 4; the ferric sulfate crystals enter the rotary kiln 6, and the pulverized coal is burned by the burner to provide heat for the rotary kiln 6. The cold air exchanges heat with the iron concentrate discharged from the rotary kiln 6 in the cooler to recover heat, and then enters the burner for combustion support. In the rotary kiln 6, the ferric sulfate is thermally decomposed to produce iron sesquioxide iron concentrate and sulfur trioxide flue gas; the sulfur trioxide flue gas enters the sulfuric acid absorption tower 7;

[0033] Flue gas enters treatment box 701 and filter plate 702 through first transfer pipe 705 for pretreatment. After dust reduction treatment, the flue gas is discharged from second transfer pipe 706 into sulfuric acid absorption tower 7. Water pump 709 is activated according to the flue gas volume to guide the treatment solution in solution storage area 707 to fifth transfer pipe 711 through fourth transfer pipe 710. Fifth transfer pipe 711 discharges the solution into water pipe 712 for spraying through nozzle 713. Combined with buffer plate 714 below, the flue gas and the treatment solution fully contact and react chemically to produce sulfuric acid. The sulfuric acid product is then transported out of the system through sulfuric acid absorption circulation pump 8.

[0034] The following steps can be implemented to produce iron concentrate and sulfuric acid by desulfurization of limonite flue gas:

[0035] A. The raw material limonite solution and flue gas enter the desulfurization tower (1). In the desulfurization tower (1), sulfur dioxide reacts with iron oxide in the limonite to form ferrous sulfite, which is further oxidized to form ferric sulfate.

[0036] B. The ferric sulfate solution enters the silicon slag filter (3) through the desulfurization liquid circulation pump (2) for filtration, the filter cake obtained by filtration is silicon slag, and the filtrate obtained by filtration is the ferric sulfate solution;

[0037] C. The ferric sulfate solution enters the concentrating crystallizer (4), where the ferric sulfate solution is concentrated and crystallized to obtain a ferric sulfate solid-liquid mixture;

[0038] D. The ferric sulfate solid-liquid mixture enters the centrifuge (5) for separation. The separated solid is ferric sulfate crystals, and the separated liquid is the mother liquor that returns to the concentrating crystallizer;

[0039] E. Ferric sulfate crystals enter the rotary kiln (6), and the pulverized coal is burned by the burner to provide heat for the rotary kiln. The cold air exchanges heat with the iron concentrate discharged from the rotary kiln in the cooler to recover heat and then enters the burner to assist combustion. In the rotary kiln, the ferric sulfate is decomposed by heat to produce ferric oxide (iron concentrate) and sulfur trioxide flue gas;

[0040] F. Sulfur trioxide flue gas enters the sulfuric acid absorption tower (7), and sulfuric acid enters the sulfuric acid absorption tower (7) through the sulfuric acid absorption circulation pump (8). In the sulfuric acid absorption tower (7), sulfuric acid absorbs sulfur trioxide gas to generate sulfuric acid, and the product sulfuric acid is transported out of the system through the sulfuric acid absorption circulation pump (8).

[0041] The raw material for step A, limonite, contains 20-40% Fe and 40-50% SiO2, and the limonite solution has a concentration of 20-40%. The raw materials can be limonite, sulfuric acid slag, low- to medium-grade iron ore, steel slag, or other iron-containing materials. The boiler flue gas temperature is 130-150°C, with a liquid-to-gas ratio of 1:1000. The rotary kiln operating conditions for step E are: a decomposition temperature of 900-950°C, a reaction time of 1 hour, an oxidizing decomposition atmosphere, and an oxygen content of ≥2-4% in the kiln exhaust gas. The sulfuric acid absorption tower control process conditions are: a temperature of 60-80°C, and a liquid-to-gas ratio of 1:500.

[0042] Desulfurization mechanism: Iron oxide reacts chemically with sulfur dioxide in the flue gas to produce ferrous sulfite, which is further oxidized to produce ferric sulfate. The main reactions are:

[0043] Fe2O3+3SO2→Fe2(SO3)3

[0044] Fe2(SO3)3+1.5O2→Fe2(SO4)3

[0045] Pyrolysis mechanism: Ferric sulfate enters a rotary kiln for high-temperature calcination, controlling the temperature at 900-950°C for 60 minutes with an air excess of 5%. The reactions involved are:

[0046] Fe2(SO4)3→Fe2O3+3SO3

[0047] Sulfuric acid absorption mechanism: Sulfuric acid is used to absorb sulfur trioxide to produce sulfuric acid, and the absorption temperature and concentration are controlled by heat exchange to produce qualified sulfuric acid products. The main reactions involved are:

[0048] SO3+H2O→H2SO4

[0049] Example 1

[0050] according to Figure 1 The process flow shown in the figure requires that the raw material limonite contains 30% Fe and 50% SiO2, the concentration of the limonite solution is 30%, and the limonite solution is controlled at 100 kg / h.

[0051] Desulfurization tower control: boiler flue gas temperature 130℃~150℃, liquid-gas ratio 1:1000.

[0052] Control the ferrous sulfate rate to 100 kg / h, the rotary kiln calcination temperature to 930°C, the calcination time to 1 hour, and the oxygen content in the flue gas to 3%;

[0053] Sulfuric acid absorption tower control: absorption liquid sulfuric acid concentration 98%, temperature 60℃, liquid-gas ratio 1:500.

[0054] According to the above process operation, the final analysis results are as follows:

[0055] Iron concentrate: iron content 68.1%

[0056] Sulfuric acid: H2SO4 98.1%.

[0057] Desulfurization tower: desulfurization efficiency is 93.6%, and the sulfur content of desulfurized tail gas is 45mg / M3.

[0058] Example 2

[0059] according to Figure 1 The process flow shown in the figure requires that the raw material limonite contains 35% Fe and 45% SiO2, the concentration of the limonite solution is 35%, and the limonite solution is controlled at 100 kg / h.

[0060] Desulfurization tower control: boiler flue gas temperature 130℃~150℃, liquid-gas ratio 1:1000.

[0061] Control the ferrous sulfate rate to 100 kg / h, the rotary kiln calcination temperature to 950°C, the calcination time to 1 hour, and the oxygen content in the flue gas to 3%;

[0062] Sulfuric acid absorption tower control: absorption liquid sulfuric acid concentration 98%, temperature 65℃, liquid-gas ratio 1:500.

[0063] According to the above process operation, the final analysis results are as follows:

[0064] Iron concentrate: iron content 67.2%

[0065] Sulfuric acid: H2SO4 98.3%.

[0066] Desulfurization tower: desulfurization efficiency is 92.8%, and the sulfur content of desulfurized tail gas is 46mg / M3.

[0067] Example 3

[0068] according to Figure 1 The process flow shown in the figure requires that the raw material limonite contains 35% Fe and 45% SiO2, the concentration of the limonite solution is 35%, and the limonite solution is controlled at 200 kg / h.

[0069] Desulfurization tower control: boiler flue gas temperature 130℃~150℃, liquid-gas ratio 1:1000.

[0070] Control the ferrous sulfate rate to 200 kg / h, the rotary kiln calcination temperature to 950°C, the calcination time to 1 hour, and the oxygen content in the flue gas to 3%;

[0071] Sulfuric acid absorption tower control: absorption liquid sulfuric acid concentration 98%, temperature 60℃, liquid-gas ratio 1:500.

[0072] According to the above process operation, the final analysis results are as follows:

[0073] Iron concentrate: iron content 66.8%

[0074] Sulfuric acid: H2SO4 98.4%.

[0075] Desulfurization tower: desulfurization efficiency is 91.9%, and the sulfur content of desulfurized tail gas is 43mg / M3.

[0076] It is also possible to completely realize the desulfurization of limonite flue gas to produce iron concentrate and co-produce sulfuric acid, and the obtained iron concentrate has high iron content, high sulfuric acid concentration and good desulfurization efficiency.

[0077] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas, comprising a desulfurization tower (1), a desulfurization liquid circulation pump (2), a silicon slag filter (3), a concentration crystallizer (4), a centrifuge (5), a rotary kiln (6), a sulfuric acid absorption tower (7) and a sulfuric acid absorption circulation pump (8), characterized in that: The desulfurization tower (1), the desulfurization liquid circulation pump (2), the silicon slag filter (3), the concentration crystallizer (4), the centrifuge (5), the rotary kiln (6), the sulfuric acid absorption tower (7) and the sulfuric acid absorption circulation pump (8) are connected in sequence. The desulfurization liquid circulation pump (2) is used for conveying the desulfurization liquid; the silicon slag filter (3) is used for filtering the desulfurization slurry to obtain silicon slag filter cake and ferric sulfate filtrate; the concentration crystallizer (4) is used for concentrating the ferric sulfate solution and crystallizing the ferric sulfate; the centrifuge (5) is used for separating the ferric sulfate crystals and the ferric sulfate mother liquor; the rotary kiln (6) is used for oxidizing and decomposing the ferric sulfate to produce iron concentrate and sulfur trioxide flue gas; the sulfuric acid absorption tower (7) is used for sulfuric acid to absorb sulfur trioxide in the flue gas to produce sulfuric acid; and the sulfuric acid absorption circulation pump (8) is used for pressurized conveying of sulfuric acid.

2. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 1, characterized in that: One side of the sulfuric acid absorption tower (7) is connected to a treatment box (701), and a filter plate (702) is connected inside the treatment box (701) for treating and reducing dust on sulfur trioxide gas. A double-layer spray structure is provided inside the sulfuric acid absorption tower (7), and a circulating spray structure is connected to one side of the lower end of the sulfuric acid absorption tower (7). The lower end of the sulfuric acid absorption tower (7) is connected to a long plate (9), and the four corners of the lower end of the long plate (9) are connected to springs (901), a damper (902) is provided inside the spring (901), and the lower end of the spring (901) is connected to a vertical cylinder (903).

3. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 2, characterized in that: A vertical plate (703) is connected to the bottom of the treatment box (701), and a recovery box (704) is connected to the lower end of the treatment box (701). A first transfer pipe (705) is connected to the upper end of one side of the treatment box (701), and a second transfer pipe (706) is connected to the other side of the first transfer pipe (705). One end of the second transfer pipe (706) is connected to the sulfuric acid absorption tower (7).

4. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 3, characterized in that: A solution placement area (707) is provided at the lower end of the interior of the sulfuric acid absorption tower (7). Two third transfer pipes (708) are connected to one end of the outer side of the sulfuric acid absorption tower (7) near the solution placement area (707). One end of each of the two third transfer pipes (708) is connected to a water pump (709), and one end of the water pump (709) is connected to a fourth transfer pipe (710).

5. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 4, characterized in that: One end of the fourth transmission tube (710) is connected to the fifth transmission tube (711) via a flange ring, and the other side of the fifth transmission tube (711) is connected to multiple water pipes (712) at equal intervals, and the lower ends of the water pipes (712) are connected to multiple nozzles (713).

6. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 5, characterized in that: A buffer plate (714) is spaced apart below the nozzle (713), and a plurality of through holes are provided on the buffer plate (714).

7. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 1, characterized in that The upper end of the interior of the sulfuric acid absorption tower (7) is connected to a demisting plate (715), and the middle portion of the upper end of the sulfuric acid absorption tower (7) is connected to an exhaust pipe (716).

8. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 1, characterized in that A concentrating crystallizer (4) and a centrifuge (5) are provided between the silicon slag filter (3) and the rotary kiln (6), and the mother liquor separated by the centrifuge (5) is returned to the concentrating crystallizer (4) through a pipeline.

9. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 8, characterized in that: The concentrating crystallizer (4) comprises a barrel (401), the barrel (401) is internally connected to a rotating rod (402), and the rotating rod (402) is externally provided with two stirring rods (403) at the upper and lower ends, respectively. The upper end of the rotating rod (402) is connected to a motor (404).

10. The system for producing iron concentrate and sulfuric acid by desulfurizing limonite flue gas according to claim 9, characterized in that: The outer wall of the barrel (401) is connected to a heat-conducting ring plate (405), and a plurality of heaters (406) are connected at equal intervals inside the heat-conducting ring plate (405). A protective cover (407) is provided outside the barrel (401), and an electric valve (408) is connected to the lower end of the barrel (401).

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