Production system for co-production of phosphoric acid from iron ore concentrate

Abstract

The utility model discloses an iron ore concentrate co-production phosphoric acid production system which comprises a rotary kiln, a desulfurizing tower, a slurry delivery pump, a gypsum filter and an acid decomposer, the exhaust end of the rotary kiln is connected with the desulfurizing tower through a pipeline, the slurry discharge end of the desulfurizing tower is connected with the slurry delivery pump through a pipeline, and the output end of the slurry delivery pump is connected with the gypsum filter through a pipeline. The device has the following advantages that sulfur trioxide and sulfur dioxide flue gas generated in the production process of iron ore concentrate are reasonably utilized, so that sulfur elements in the sulfur trioxide and sulfur dioxide flue gas react with calcium-containing acidolysis liquid in the desulfurization tower to generate slurry, and the slurry is recycled, so that the calcium-containing acidolysis liquid can be recycled, and the sulfur-containing acidolysis liquid can be recycled. The slurry is processed into a gypsum finished product and a dilute phosphoric acid solution through a gypsum filter, and then a part of calcium-containing acidolysis liquid flows back to the desulfurizing tower, so that a whole set of iron ore concentrate co-production phosphoric acid based on ferrous sulfate is formed.

Description

Technical Field

[0001] The utility model relates to the technical field of mineral engineering, in particular to an iron ore concentrate co-production phosphoric acid production system. Background Art

[0002] Ferrous sulfate, a byproduct of titanium dioxide, is currently mainly used in the production of cement chromium reduction agent, feed additive (monohydrate), polyferrous sulfate, sulfuric acid blending and other traditional applications. The traditional downstream is oversaturated; a large number of uses are used to produce iron phosphate. Recently, due to the overcapacity of iron phosphate, the demand has been greatly reduced. There is an urgent need to develop new uses, increase consumption, and improve added value.

[0003] Ferrous sulfate is rich in iron and sulfur and is a good resource of iron and sulfur. Currently, only a small amount of ferrous sulfate is calcined to produce iron red, and the sulfur resource is simply neutralized with lime. The present invention can process a large amount of ferrous sulfate. The iron trioxide (containing nearly 70% iron) produced by high-temperature calcination is a high-quality iron concentrate, but a large amount of sulfur trioxide and sulfur dioxide flue gas will be produced, which is a major environmental problem. The innovation of the present invention is: using the calcium-containing acid solution produced by the reaction of phosphate rock and phosphoric acid as a desulfurizer to remove sulfur trioxide and sulfur dioxide in the flue gas, and using the calcium resources in the phosphate rock for desulfurization. Sulfur trioxide and sulfur dioxide flue gas replace sulfuric acid for phosphoric acid production, and phosphoric acid production does not require sulfuric acid raw materials.

[0004] The production of wet phosphoric acid requires the construction of a sulfuric acid plant and the purchase of sulfur or pyrite raw materials. The construction investment is large and the raw material cost is high. If sulfur trioxide and sulfur dioxide in the flue gas are used instead of sulfuric acid, the cost of phosphoric acid can be greatly reduced, which has good economic and environmental benefits.

[0005] The advantages and disadvantages of each process are combined to achieve maximum resource utilization and reduce pollution. Based on this purpose, the maximum advantage is obtained: high-value utilization of by-product ferrous sulfate and phosphoric acid production. At the same time, the iron resources in the low-value ferrous sulfate by-product of titanium dioxide are used to produce high-quality iron concentrate, and the sulfur resources are used to produce sulfur trioxide and sulfur dioxide flue gas. At the same time, sulfur trioxide and sulfur dioxide flue gas replace sulfuric acid to react with phosphate rock to produce phosphoric acid, eliminating the sulfuric acid cost required for phosphoric acid production. At the same time, the calcium resources in the phosphate rock are used for desulfurization, and finally the low-value ferrous sulfate is resourced and valued, which completely solves the outlet problem of titanium dioxide by-product ferrous sulfate. At present, there is no ferrous sulfate production iron concentrate co-production phosphoric acid system. Utility Model Content

[0006] In order to solve the problems in the above background technology, the technical solution adopted by the utility model to solve the technical problems is: an iron concentrate co-production phosphoric acid production system, which includes: a rotary kiln, a desulfurization tower, a slurry delivery pump, a gypsum filter, and an acid decomposer. The exhaust end of the rotary kiln is connected to the desulfurization tower through a pipeline, the slurry discharge end of the desulfurization tower is connected to the slurry delivery pump through a pipeline, the output end of the slurry delivery pump is connected to the gypsum filter through a pipeline, the gypsum filter is connected to the acid decomposer through a pipeline, and the acid decomposer is refluxed and connected to the desulfurization tower, the rotary kiln is connected to a ferrous sulfate bin through a pipeline, the rotary kiln is connected to a burner through a pipeline, and is connected to a cooler through a pipeline.

[0007] The rotary kiln is used for oxidative decomposition of ferrous sulfate to produce iron concentrate and sulfur trioxide and sulfur dioxide flue gas;

[0008] The desulfurization tower reacts with the flue gas and the calcium-containing acid solution to produce calcium sulfate (gypsum), thereby removing sulfur trioxide and sulfur dioxide from the flue gas;

[0009] The slurry delivery pump is used to deliver gypsum slurry;

[0010] The gypsum filter is used to filter the gypsum slurry to obtain gypsum filter cake and phosphoric acid filtrate;

[0011] The acid decomposer is used for the reaction of phosphoric acid and phosphate rock to obtain calcium-containing acid solution.

[0012] The acid decomposer is provided with a crushing structure to assist the reaction and decompose part of the calcium-containing acid solution to flow back to the desulfurization tower.

[0013] The system as a whole can realize the following process: the raw material ferrous sulfate (anhydrous) in the ferrous sulfate bin enters the rotary kiln, the pulverized coal is burned through the burner to provide heat for the inside of the rotary kiln, the cold air exchanges heat with the iron concentrate discharged from the rotary kiln in the cooler to recover heat and enter the burner to assist combustion, and the ferrous sulfate is oxidized and decomposed by heat in the rotary kiln to produce ferric oxide (iron concentrate) and sulfur trioxide and sulfur dioxide flue gas; the raw materials phosphate rock and phosphoric acid (only used for the first time when the machine is started) are transported to the acid decomposer, and the phosphate rock and phosphoric acid undergo a decomposition reaction in the acid decomposer to obtain a calcium-containing acid solution, The calcium-containing acid solution is then transported to the desulfurization tower, where calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitates, wherein the calcium sulfite is further oxidized to obtain calcium sulfate (gypsum). The calcium sulfate slurry is transported to the gypsum filter through a slurry delivery pump. The filter cake produced by the gypsum filter is a calcium sulfate product, and the filtrate is phosphoric acid, wherein a part of the phosphoric acid is discharged as a product, and the other part is transported to the acid decomposer for reuse to form a calcium acid solution for use in the desulfurization tower, and the processing is repeated over and over again.

[0014] As a preferred technical solution of the utility model, the rotary kiln includes a kiln body, a kiln tail and a kiln head. A driving mechanism is arranged on the outer side of the middle part of the kiln body, and the driving mechanism is installed on a bracket.

[0015] As a preferred technical solution of the utility model, both ends of the kiln cylinder are provided with load-bearing rings, and the bracket is located on one side of the load-bearing ring and is equipped with a roller.

[0016] As a preferred technical solution of the utility model, a raw material inlet is arranged at one side of the upper end of the kiln tail, and a smoke exhaust pipe is arranged at one side of the kiln tail close to the raw material inlet, and the smoke exhaust pipe is connected to the desulfurization tower.

[0017] As a preferred technical solution of the utility model, a flow groove is provided between the smoke exhaust pipe and the raw material inlet, and the kiln tail is movably connected to one end of the kiln cylinder.

[0018] As a preferred technical solution of the utility model, the kiln head is provided with a discharge port at the bottom side near one end of the kiln cylinder, the inner side of the kiln head is movably connected to the other end of the kiln cylinder, and the discharge port is connected to a cooler.

[0019] As a preferred technical solution of the utility model, refractory mud is arranged inside the kiln cylinder, refractory bricks are arranged inside the refractory mud, and the number of the refractory bricks is set to be several.

[0020] As a preferred technical solution of the utility model, the raw material inlet is connected to the ferrous sulfate bin through a pipeline.

[0021] As a preferred technical solution of the utility model, the kiln head is connected to the burner, and the kiln head is connected to the bracket through a guide rail.

[0022] The utility model has the following advantages: the system as a whole can realize the following process: the raw material ferrous sulfate (anhydrous) in the ferrous sulfate bin enters the rotary kiln, the pulverized coal is burned by the burner to provide heat for the inside of the rotary kiln, the cold air exchanges heat with the iron concentrate discharged from the rotary kiln in the cooler to recover heat and enter the burner to assist combustion, the ferrous sulfate is heated and oxidized and decomposed in the rotary kiln to produce ferric oxide (iron concentrate) and sulfur trioxide and sulfur dioxide flue gas; the raw material phosphate rock and phosphoric acid (only used for the first time when the machine is started) are transported to the acid decomposer, and the phosphate rock and phosphoric acid undergo a decomposition reaction in the acid decomposer to obtain The calcium-containing acid solution is then transported to the desulfurization tower, where calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitation, wherein calcium sulfite is further oxidized to obtain calcium sulfate (gypsum), and the calcium sulfate slurry is transported to the gypsum filter through a slurry delivery pump. The filter cake produced by the gypsum filter is a calcium sulfate product, and the filtrate is phosphoric acid, wherein a part of the phosphoric acid is discharged as a product, and the other part of the phosphoric acid is transported to the acid decomposer for reuse to form calcium acid solution to be used in the desulfurization tower, and the processing is repeated. The production system of ferrous sulfate to produce iron concentrate and phosphoric acid is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the system connection diagram of the utility model;

[0024] Figure 2 It is a schematic diagram of the structure of a rotary kiln in a preferred embodiment of the utility model;

[0025] Figure 3 This is a schematic diagram of the kiln tail structure of a preferred embodiment of the utility model;

[0026] Figure 4 It is a schematic diagram of the cross-sectional structure of a kiln cylinder according to a preferred embodiment of the utility model.

[0027] Figure 5 It is a structural schematic diagram of the decomposer of the utility model.

[0028] Figure 6 It is a schematic diagram of the internal structure of the decomposer of the utility model.

[0029] Figure 7 For the utility model Figure 3 A schematic diagram of the structure enlarged

[0030] Explanation of the reference numerals in the accompanying drawings: 1. rotary kiln; 101. kiln body; 1011. refractory clay; 1012. refractory bricks; 102. kiln tail; 103. kiln head; 2. desulfurization tower; 3. slurry delivery pump; 4. gypsum filter; 5. acid decomposer; 6. cooler; 7. ferrous sulfate bin; 8. burner; 9. driving mechanism; 10. bracket; 11. roller; 12. load-bearing ring; 13. raw material inlet; 14. smoke exhaust pipe; 1401. circulation chute; 15. discharge port.

[0031] 511. decomposer housing; 512. feed pipe; 513. drive motor; 514. rotating rod; 515. crushing roller; 516. first pulley; 517. connecting belt; 518. second pulley; 519. first gear; 520. second gear; 521. rotating rod; 522. connecting piece; 523. connecting rod; 524. cleaning roller; 525. discharging piece; 526. vertical rod; 527. horizontal plate 5; 28. moving piece. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The utility model will be further described below in conjunction with the accompanying drawings.

[0035] Please refer to Figure 1-Figure 4The utility model discloses an iron concentrate co-production phosphoric acid production system, comprising: a rotary kiln 1, a desulfurization tower 2, a slurry delivery pump 3, a gypsum filter 4, and an acid decomposer 5. The exhaust end of the rotary kiln 1 is connected to the desulfurization tower 2 through a pipeline, the slurry discharge end of the desulfurization tower 2 is connected to the slurry delivery pump 3 through a pipeline, the output end of the slurry delivery pump 3 is connected to the gypsum filter 4 through a pipeline, the gypsum filter 4 is connected to the acid decomposer 5 through a pipeline, and the acid decomposer is refluxed and connected to the desulfurization tower 2. The rotary kiln 1 is connected to a ferrous sulfate bin 8 through a pipeline, the rotary kiln 1 is connected to a burner 9 through a pipeline, and is also connected to a cooler 10 through a pipeline.

[0036] The rotary kiln 1 is used for oxidative decomposition of ferrous sulfate to produce iron concentrate and sulfur trioxide and sulfur dioxide flue gas;

[0037] The desulfurization tower 2 reacts the flue gas with the calcium-containing acid solution to produce calcium sulfate (gypsum), thereby removing sulfur trioxide and sulfur dioxide from the flue gas;

[0038] The slurry delivery pump 3 is used to deliver gypsum slurry;

[0039] The gypsum filter 4 is used to filter the gypsum slurry to obtain gypsum filter cake and phosphoric acid filtrate;

[0040] The acid decomposer 5 is used for the reaction of phosphoric acid with phosphate rock to obtain a calcium-containing acid solution.

[0041] The acid decomposer 5 is provided with a crushing structure to assist the reaction and decompose part of the calcium-containing acid solution to flow back to the desulfurization tower 2 .

[0042] The above production system can realize multiple process integration and reflux cycle desulfurization processing, including the following:

[0043] A raw material anhydrous ferrous sulfate enters the rotary kiln 1, 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 enter the burner to assist combustion, and the ferrous sulfate is oxidized and decomposed by heat in the rotary kiln to produce ferric oxide (iron concentrate) and sulfur trioxide and sulfur dioxide flue gas;

[0044] B raw materials phosphate rock and phosphoric acid are only used for the first time and enter the acid decomposer 5, in which the phosphate rock and phosphoric acid undergo a decomposition reaction to obtain a calcium-containing acid solution;

[0045] The calcium-containing acid solution enters the desulfurization tower 2, where calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitation, wherein the calcium sulfite is further oxidized to obtain gypsum (calcium sulfate), and the calcium sulfate slurry is transported to the gypsum filter 4 through the slurry pump 3;

[0046] The filter cake produced by the D gypsum filter is a calcium sulfate (gypsum) product, and the filtrate is phosphoric acid. A portion of the phosphoric acid is extracted as a product, and a portion of the phosphoric acid is refluxed to the desulfurization tower to be recycled again after the acid decomposer.

[0047] The above steps form a cyclic processing of producing iron ore concentrate and phosphoric acid based on ferrous sulfate, and achieve desulfurization in a desulfurization tower based on ferrous sulfate rotary kiln 1.

[0048] Combination Figure 2 As shown, the rotary kiln 1 includes a kiln body 101, a kiln tail 102, and a kiln head 103. A driving mechanism 9 is arranged on the outer side of the middle of the kiln body 101. The driving mechanism 9 is installed on a bracket 10. Both ends of the kiln body 101 are provided with a bearing ring 12. The bracket 10 is located on one side of the bearing ring 12 and is equipped with a roller 11. Figure 3 As shown, a raw material inlet 13 is provided on one side of the upper end of the kiln tail 102, and a smoke exhaust pipe 14 is provided on the side of the kiln tail 102 close to the raw material inlet 13. The smoke exhaust pipe 14 is connected to the desulfurization tower 2, and a flow groove 1401 is provided between the smoke exhaust pipe 14 and the raw material inlet 13. The flow groove 1401 facilitates the transportation of flue gas to the smoke exhaust pipe 14. The kiln tail 102 is movably connected to one end of the kiln cylinder 101, and the raw material inlet 13 is connected to the ferrous sulfate bin 7 through a pipeline.

[0049] The kiln head 103 is located near the bottom of one end of the kiln body 101 and is provided with a discharge port 15. The inner side of the kiln head 103 is movably connected to the other end of the kiln body 101. The discharge port 15 is connected to a cooler 6. Figure 4 As shown, refractory mud 1011 is arranged inside the kiln cylinder 101, refractory bricks 1012 are arranged inside the refractory mud 1011, and the number of refractory bricks 1012 is set. The kiln head 103 is connected to the burner 8, and the kiln head 103 is connected to the bracket 10 through a guide rail.

[0050] Specifically, when the utility model is used, the raw material ferrous sulfate (anhydrous) in the ferrous sulfate bin 7 enters the rotary kiln 1, the pulverized coal is burned by the burner 8 to provide heat for the inside of the rotary kiln 1, the cold air exchanges heat with the iron concentrate discharged from the rotary kiln 1 in the cooler 6 to recover heat and enter the burner 8 to assist combustion, and the ferrous sulfate in the rotary kiln 1 is heated, oxidized and decomposed to produce ferric oxide (iron concentrate) and sulfur trioxide and sulfur dioxide flue gas;

[0051] The raw materials phosphate rock and phosphoric acid (only for start-up) are transported to the acid decomposer 5, where the phosphate rock and phosphoric acid undergo a decomposition reaction to obtain a calcium-containing acid solution, and the calcium-containing acid solution is then transported to the desulfurization tower 2, where calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitation, wherein the calcium sulfite is further oxidized to obtain calcium sulfate (gypsum), and the calcium sulfate slurry is transported to the gypsum filter 4 through the slurry delivery pump 3, and the filter cake produced by the gypsum filter 4 is a calcium sulfate product, and the filtrate is phosphoric acid, wherein a part of the phosphoric acid is discharged as a product, and the other part of the phosphoric acid is transported to the acid decomposer 5 for reuse.

[0052] The acid decomposer can be referred to as follows: as shown in the figure, the acid decomposer 5 includes a decomposer shell 511, a feed pipe 512 is arranged on the upper end surface of the decomposer shell 511, and two groups of drive motors 513 are arranged on the outer wall of the decomposer shell 511. The output ends of the two groups of drive motors 513 pass through the decomposer shell 511 and extend to the inside of the decomposer shell 511, and are connected to a group of rotating rods 514. The other ends of the two groups of rotating rods 514 are connected to the inner wall of the other end of the decomposer shell 511, and the outer walls of the two groups of rotating rods 514 are sleeved with a group of crushing rollers 515; the outer walls of the two groups of rotating rods 514 are sleeved with a group of first belts 516, and the outer sides of the two groups of first pulleys 516 are sleeved with a group of connecting belts 517, and the inner sides of the other sides of the two groups of connecting belts 517 are sleeved with a group of first belts 516. A group of second pulleys 518 are provided on each of the two groups of first pulleys 516 and the second pulleys 518 are rotatably connected to the inner wall of the decomposer housing 511; a group of first gears 519 are provided on the side walls of the two groups of second pulleys 518, and a group of second gears 520 are meshed and connected to one side of the two groups of first gears 519, and a group of rotating rods 521 are provided inside the two groups of second gears 520, and the two ends of the two groups of rotating rods 521 are respectively provided on the inner walls of the two sides of the decomposer housing 511; two groups of connecting members 522 are sleeved on the outer walls of the two groups of rotating rods 521, and multiple groups of connecting rods 523 are connected to the outer walls of the two groups of connecting members 522, and a group of cleaning rollers 524 are provided on the other ends of the multiple groups of connecting rods 523, and the cleaning rollers 524 are in contact with the crushing rollers 515;

[0053] A discharge piece 525 is provided on the lower end wall of the decomposer housing 11; the material produced by the decomposition reaction can be discharged by providing the discharge piece 525. A set of vertical rods 526 are provided at the four corners of the lower end surface of the decomposer housing 511, and two sets of horizontal plates 527 are provided on the lower end surfaces of the multiple sets of vertical rods 526. A set of moving pieces 528 are provided at both ends of the lower end surfaces of the two sets of horizontal plates 527; the horizontal plates 527 can be supported by providing the vertical rods 526, and the moving pieces 528 can be supported by providing the horizontal plates 527, and the moving pieces 528 can be conveniently transferred by providing the moving pieces 528.

[0054] When the acid decomposer 5 is in use, the raw phosphate ore and phosphoric acid are transported to the interior of the decomposer housing 511 through the feed pipe 512, and two sets of drive motors 513 are started at the same time. The two sets of drive motors 513 drive two sets of crushing rollers 515 to crush the raw phosphate ore and phosphoric acid through two sets of rotating rods 514, so that the raw phosphate ore and the phosphoric acid provided for the first time can be decomposed better and faster. While rotating, the rotating rod 514 drives the first gear 519 to rotate through the first pulley 516, the connecting belt 517 and the second pulley 518. The first gear 519 drives the rotating rod 21 to rotate through the second gear 520. The rotating rod 521 drives multiple sets of cleaning rollers 524 to rotate through the connecting piece 522, so that the multiple sets of cleaning rollers 524 can scrape the residue on the crushing rollers 515 to avoid the raw materials remaining on the crushing rollers 515. It is relatively practical and ensures the full decomposition reaction of the material. The crushing structure is set to assist the reaction to decompose the calcium-containing acid solution, so that the phosphate ore and phosphoric acid undergo a decomposition reaction to obtain the calcium-containing acid solution and return it to the desulfurization tower, so that the calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitation, thereby realizing the continuity of the process and the connected operation of the overall system.

[0055] Its desulfurization tower, slurry delivery pump, gypsum filter, cooler, ferrous sulfate bin and burner are conventional equipment and can be directly used in existing equipment.

[0056] The above are only preferred implementations of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

[0057] Other parts of the present invention not described in detail belong to the prior art and will not be described in detail here.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An iron ore concentrate co-production phosphoric acid production system, characterized in that: include: A rotary kiln (1), a desulfurization tower (2), a slurry delivery pump (3), a gypsum filter (4), and an acid decomposer (5); the exhaust end of the rotary kiln (1) is connected to the desulfurization tower (2) via a pipeline; the slurry discharge end of the desulfurization tower (2) is connected to the slurry delivery pump (3) via a pipeline; the output end of the slurry delivery pump (3) is connected to the gypsum filter (4) via a pipeline; the gypsum filter (4) is connected to the acid decomposer (5) via a pipeline; the acid decomposer is then refluxed and connected to the desulfurization tower (2); the rotary kiln (1) is connected to a ferrous sulfate bin (8) via a pipeline; the rotary kiln (1) is connected to a burner (9) via a pipeline; and is also connected to a cooler (10) via a pipeline.

2. The iron ore concentrate co-production phosphoric acid production system according to claim 1, characterized in that: The rotary kiln (1) is used for oxidative decomposition of ferrous sulfate to produce iron concentrate and sulfur trioxide and sulfur dioxide flue gas.

3. The iron ore concentrate co-production phosphoric acid production system according to claim 2, characterized in that: The desulfurization tower (2) reacts the flue gas with the calcium-containing acid solution to produce calcium sulfate gypsum, thereby removing sulfur trioxide and sulfur dioxide from the flue gas.

4. The iron ore concentrate co-production phosphoric acid production system according to claim 2, characterized in that: The slurry delivery pump (3) is used for delivering gypsum slurry.

5. The iron ore concentrate co-production phosphoric acid production system according to claim 4, characterized in that: The gypsum filter (4) is used to filter the gypsum slurry to obtain gypsum filter cake and phosphoric acid filtrate.

6. The iron concentrate co-production phosphoric acid production system according to claim 2, characterized in that: The acid decomposer (5) is used for the reaction of phosphoric acid with phosphate rock to obtain a calcium-containing acid solution.

7. The iron concentrate co-production phosphoric acid production system according to claim 2, characterized in that: The rotary kiln is a kind of rotary kiln that forms multiple connections to achieve reaction conversion and is used for oxidative decomposition of ferrous sulfate to produce iron concentrate and sulfur trioxide and sulfur dioxide flue gas.

8. The iron concentrate co-production phosphoric acid production system according to claim 6, characterized in that: A crushing structure is set up to assist the reaction and decompose the calcium-containing acid solution, so that the phosphate ore and phosphoric acid undergo a decomposition reaction to obtain the calcium-containing acid solution and return it to the desulfurization tower, so that the calcium ions react chemically with sulfur trioxide and sulfur dioxide in the flue gas to generate calcium sulfate and calcium sulfite precipitation.

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