Ardealite calcining system capable of recycling waste heat and harmless treatment method of ardealite

Abstract

The invention relates to the technical field of ardealite processing, and provides a waste heat recycling ardealite calcining system and an ardealite harmless treatment method, the system comprises a rotary kiln, a flash furnace, a smoke chamber and a calcining furnace; the rotary kiln comprises a first rotary kiln body and a second rotary kiln body; the first rotary kiln body is rotatably arranged on the outer side of the second rotary kiln body in a sleeving manner, and the second rotary kiln body is rotatably arranged; a first conveying channel is formed between the first rotary kiln body and the second rotary kiln body, and a second conveying channel is formed on the inner side of the second rotary kiln body; a first material conveying channel of the rotary kiln is connected with a flash furnace, the flash furnace is connected with a smoke chamber and a calcining furnace, and the calcining furnace is connected with a second material conveying channel. According to the phosphogypsum calcining system, waste heat of high-temperature flue gas is fully utilized to perform dehydration and modification treatment on phosphogypsum, other heat energy does not need to be additionally utilized to calcine the phosphogypsum, the system energy consumption is low, normal operation of a phosphogypsum calcining production line is guaranteed, and the purposes of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphogypsum processing, and in particular to a phosphogypsum calcining system for waste heat recovery and a phosphogypsum harmless treatment method. Background Art

[0002] In gypsum production, phosphogypsum is usually dried, dehydrated and modified in sequence to obtain modified gypsum (semi-hydrated gypsum or anhydrous gypsum) with a low content of crystal water. In this process, a calcining furnace is required to calcine the phosphogypsum at high temperature. The calcination process consumes a large amount of electricity or fossil energy, and the energy consumption of the entire system is high, which is not conducive to reducing production costs. Summary of the invention

[0003] The present invention provides a phosphogypsum calcining system with waste heat recovery and a phosphogypsum harmless treatment method, which are used to at least solve or improve the problem of high energy consumption in the existing phosphogypsum calcining system.

[0004] In a first aspect, the present invention provides a phosphogypsum calcining system with waste heat recovery, comprising: a rotary kiln, a flash furnace, a smoke chamber and a calcining furnace; The rotary kiln comprises a first rotary kiln body and a second rotary kiln body; the first rotary kiln body is rotatably sleeved on the outer side of the second rotary kiln body, and the second rotary kiln body is rotatably arranged; a first material conveying channel is formed between the first rotary kiln body and the second rotary kiln body, and a second material conveying channel is formed inside the second rotary kiln body; the first material conveying channel of the rotary kiln is connected to the flash furnace, the flash furnace is respectively connected to the smoke chamber and the calcining furnace, and the calcining furnace is connected to the second material conveying channel; The first feeding channel is used to transport phosphogypsum, the flash furnace is configured to receive high-temperature flue gas and phosphogypsum output from the first feeding channel, the flash furnace uses the high-temperature flue gas output from the smoke chamber to perform a primary dehydration treatment on the phosphogypsum, and transports the primary dehydrated phosphogypsum to the calcining furnace; A first heat-conducting member is provided in the smoke chamber, and a second heat-conducting member is provided in the calcining furnace. The first heat-conducting member and the second heat-conducting member are connected in series to form a closed-loop pipeline system for circulating heat-conducting oil. The smoke chamber uses the high-temperature flue gas discharged from the kiln system to heat the heat-conducting oil flowing through the first heat-conducting member. The calcining furnace uses the second heat-conducting member to perform secondary dehydration treatment on the phosphogypsum to obtain modified gypsum. The second feed channel is used to receive the modified gypsum and realize the transportation and discharge of the modified gypsum. The second rotary kiln body is used to achieve heat exchange between the phosphogypsum transported by the first material feeding channel and the modified gypsum transported by the second material feeding channel.

[0005] According to a waste heat recovery phosphogypsum calcining system provided by the present invention, the inner wall of the first rotary kiln body and the inner wall of the second rotary kiln body are both provided with propulsion blades extending in a spiral shape.

[0006] A phosphogypsum calcining system for waste heat recovery provided by the present invention also includes a dust removal device, wherein the dust removal device includes a cyclone separator and a bag dust collector; The air inlet of the cyclone separator is connected to the flash furnace to receive the flue gas containing the phosphogypsum discharged from the flash furnace. The exhaust port of the cyclone separator is connected to the air inlet of the bag dust collector. The ash discharge port of the cyclone separator and the ash discharge port of the bag dust collector are respectively connected to the calcining furnace; the bag dust collector also has a smoke exhaust port for flue gas discharge.

[0007] According to a waste heat recovery and utilization phosphogypsum calcining system provided by the present invention, the smoke chamber comprises a heat-conducting shell and a plurality of the first heat-conducting members; The heat-conducting housing has a smoke inlet, a smoke outlet, and a serpentine flow channel formed between the smoke inlet and the smoke outlet, and the serpentine flow channel is used to pass the high-temperature smoke; Along the flow direction of the high-temperature flue gas in the serpentine flow channel, a plurality of the first heat-conducting members are sequentially arranged in the serpentine flow channel; a sandwich structure is arranged in the shell wall of the heat-conducting shell, and a fluid inlet and a fluid outlet connected to the sandwich structure are configured; The sandwich structure is arranged in parallel with the first heat-conducting member, and is respectively connected in series with the second heat-conducting member to form the closed-loop pipeline system; The flue gas inlet is configured to receive high-temperature flue gas discharged from the kiln system, and the flue gas outlet is configured to communicate with the flash furnace.

[0008] According to a waste heat recovery and utilization phosphogypsum calcining system provided by the present invention, the heat-conducting shell includes a main shell and a plurality of ash discharge hoppers; The smoke inlet and the smoke outlet are respectively arranged on the shell wall of the main shell, and a plurality of partitions are arranged in the main shell. The plurality of partitions are spaced from each other to define the serpentine flow channel in the main shell; a plurality of ash discharge hoppers are respectively arranged on the lower side of the main shell and are connected to the serpentine flow channel.

[0009] According to a waste heat recovery and utilization system for phosphogypsum calcining provided by the present invention, the calcining furnace comprises a rotary furnace body and the second heat conducting member; The second heat-conducting member is cylindrical and is disposed inside the rotary furnace body. The second heat-conducting member is configured to rotate synchronously or differentially along the same rotation direction as the rotary furnace body. A material channel is formed between the rotary furnace body and the second heat-conducting member, and the material channel is used to transport the phosphogypsum that has been subjected to a primary dehydration treatment in the flash furnace; The second heat-conducting member is used for passing heat-conducting oil, and the second heat-conducting member is used for realizing heat exchange between the heat-conducting oil and the phosphogypsum, so as to perform secondary dehydration treatment on the phosphogypsum.

[0010] According to a waste heat recovery phosphogypsum calcining system provided by the present invention, a scoop plate is provided on the inner wall of the rotary furnace body, and the scoop plate extends toward the peripheral wall of the second heat-conducting member. The scoop plate is used to move the phosphogypsum along the circumferential direction of the second heat-conducting member during the rotation of the rotary furnace body.

[0011] According to a phosphogypsum calcining system with waste heat recovery provided by the present invention, the second heat-conducting component includes a heat-conducting cylinder, which is extended along the rotation axis of the rotary furnace body, and the cross-sectional shape of the heat-conducting cylinder along a plane perpendicular to the rotation axis is star-shaped, and the heat-conducting cylinder is used to pass the heat-conducting oil.

[0012] According to a waste heat recovery phosphogypsum calcination system provided by the present invention, the second heat-conducting component also includes a center tube, which is inserted into the heat-conducting cylinder, and the gap between the inner wall of the heat-conducting cylinder and the peripheral wall of the center tube is used to pass the heat-conducting oil.

[0013] A phosphogypsum calcining system for waste heat recovery provided by the present invention further includes a first conveying line, which is arranged between the rotary kiln and the flash furnace to convey the phosphogypsum discharged from the first feeding channel of the rotary kiln to the feeding port of the flash furnace; And / or, it also includes a second conveying line, which is arranged between the calcining furnace and the rotary kiln to convey the modified gypsum output from the calcining furnace to the second material conveying channel of the rotary kiln.

[0014] In a second aspect, the present invention further provides a method for harmless treatment of phosphogypsum, comprising: using the phosphogypsum calcination system with waste heat recovery as described above to sequentially preheat, dehydrate, dry, calcine and cool the phosphogypsum.

[0015] The waste heat recovery and utilization phosphogypsum calcining system and the harmless treatment method of phosphogypsum provided by the present invention are provided with a rotary kiln, a flash furnace, a smoke chamber and a calcining furnace. In practical application, the rotary kiln transports the phosphogypsum to the flash furnace. The flash furnace uses the waste heat of the high-temperature flue gas output from the smoke chamber to flash-dry the phosphogypsum to remove most of the attached water in the phosphogypsum. The smoke chamber uses the high-temperature flue gas discharged from the kiln system to heat the heat transfer oil circulating in the first heat transfer element. The phosphogypsum that has been dehydrated once is transported to the calcining furnace for calcining. Since the first heat transfer element is connected in series with the second heat transfer element in the calcining furnace to form a closed-loop pipeline system for circulating the heat transfer oil, the first heat transfer element is connected in series with the second heat transfer element in the calcining furnace to form a closed-loop pipeline system for circulating the heat transfer oil. In the rotary kiln, the heat transfer oil can be used to transfer heat to the second heat transfer member, and then the second heat transfer member heats the phosphogypsum to convert the phosphogypsum into modified gypsum such as hemihydrate gypsum and anhydrous gypsum. The modified gypsum is returned to the second feed channel of the rotary kiln, and the phosphogypsum transported by the first feed channel and the modified gypsum transported by the second feed channel are heat exchanged to achieve the use of the thermal energy of the modified gypsum for drying pretreatment of the phosphogypsum, and the cooling of the modified gypsum is completed at the same time. The phosphogypsum that has been dried and pretreated is then successively dehydrated and modified in a flash furnace and a calcining furnace, and finally cooled and output through a rotary kiln. This process is repeated to achieve the calcination of the phosphogypsum.

[0016] From the above, it can be seen that the phosphogypsum calcining system shown in the present invention fully utilizes the waste heat of high-temperature flue gas to achieve dehydration and modification of phosphogypsum, without the need to use other thermal energy to calcine phosphogypsum. The system has low energy consumption, which not only ensures the normal operation of the phosphogypsum calcining production line, but also achieves the purpose of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic structural diagram of a phosphogypsum calcining system for waste heat recovery provided by an embodiment of the present invention.

[0019] Figure 2 This is one of the structural schematic diagrams of a phosphogypsum calcining system for waste heat recovery and utilization provided by another embodiment of the present invention.

[0020] Figure 3 This is the second structural schematic diagram of a phosphogypsum calcining system for waste heat recovery and utilization provided by another embodiment of the present invention.

[0021] Figure 4 It is a structural schematic diagram of the rotary kiln provided by the present invention.

[0022] Figure 5 It is a schematic diagram of the installation of the flash furnace and dust removal equipment provided by the present invention.

[0023] Figure 6 This is one of the structural schematic diagrams of the smoke chamber provided by the present invention.

[0024] Figure 7 This is the second structural schematic diagram of the smoke chamber provided by the present invention.

[0025] Figure 8 This is the third structural schematic diagram of the smoke chamber provided by the present invention.

[0026] Fig. 9 It is a schematic structural diagram of the first heat conducting member provided by the present invention.

[0027] Fig.10 The present invention provides Figure 2 One of the structural diagrams of the calcining furnace.

[0028] Fig.11 The present invention provides Figure 2 The second structural diagram of the calcining furnace.

[0029] Fig.12 The present invention provides Figure 2 One of the structural schematic diagrams of the second heat conducting member.

[0030] Fig.13 The present invention provides Figure 2 The second structural schematic diagram of the second heat conducting member.

[0031] Fig.14 The present invention provides Figure 2 The third structural diagram of the second heat conducting member.

[0032] Reference numerals: 1. Rotary kiln; 11. First rotary kiln body; 12. Second rotary kiln body; 13. First feeding hopper; 14. Second feeding hopper; 15. First discharge bin; 16. Second discharge bin; 101. First feeding channel; 102. Second feeding channel; 10. Propelling blade; 2. Flash furnace; 21. Furnace body; 22. Crushing mechanism; 201. Smoke inlet; 202. Material inlet; 203. Smoke and material outlet; 3. Dust removal equipment; 31. Cyclone separator; 32. Bag dust collector; 4. Smoke chamber; 401. Smoke inlet; 402. Smoke outlet; 403. Serpentine flow channel; 41. Heat-conducting shell; 42. First heat-conducting member; 411. Main shell; 412. Ash hopper; 4110. Partition; 4100. Sandwich structure; 421. Coil unit; 4201. Smoke channel; 5. calcining furnace; 501. material channel; 51. rotary furnace body; 511. scoop plate; 52. second heat-conducting member; 521. heat-conducting cylinder; 522. adapter; 523. center tube; 53. rotary drive assembly; 531. drive motor; 532. gear assembly; 533. gear ring; 54. rotary support; 55. upper hopper; 56. discharge bin; 6. The first conveyor line; 7. The second conveyor line. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Combine the following Figure 1-Figure 14 The phosphogypsum calcining system with waste heat recovery and the phosphogypsum harmless treatment method provided by the embodiments of the invention are described in detail through specific embodiments and their application scenarios.

[0035] In the first aspect, Figure 1 , Figure 2 and Figure 3 As shown, the embodiment of the present invention provides a phosphogypsum calcining system for waste heat recovery, comprising a rotary kiln 1, a flash furnace 2, a smoke chamber 4 and a calcining furnace 5; The rotary kiln 1 comprises a first rotary kiln body 11 and a second rotary kiln body 12; the first rotary kiln body 11 is rotatably sleeved on the outer side of the second rotary kiln body 12, and the second rotary kiln body 12 is rotatably arranged; a first material conveying channel 101 is formed between the first rotary kiln body 11 and the second rotary kiln body 12, and a second material conveying channel 102 is formed on the inner side of the second rotary kiln body 12; the first material conveying channel 101 of the rotary kiln 1 is connected to the flash furnace 2, the flash furnace 2 is respectively connected to the smoke chamber 4 and the calcining furnace 5, and the calcining furnace 5 is connected to the second material conveying channel 102; The first feeding channel 101 is used to transport phosphogypsum. The flash furnace 2 is configured to receive the high-temperature flue gas and the phosphogypsum output from the first feeding channel 101. The flash furnace 2 uses the high-temperature flue gas output from the smoke chamber 4 to perform a primary dehydration treatment on the phosphogypsum, and transports the dehydrated phosphogypsum to the calcining furnace 5. A first heat-conducting member 42 is provided in the smoke chamber 4, and a second heat-conducting member 52 is provided in the calcining furnace 5. The first heat-conducting member 42 and the second heat-conducting member 52 are connected in series to form a closed-loop pipeline system for circulating heat-conducting oil. The smoke chamber 4 heats the heat-conducting oil flowing through the first heat-conducting member 42 by using the high-temperature flue gas discharged from the external kiln system. The calcining furnace 5 performs secondary dehydration treatment on the phosphogypsum by using the second heat-conducting member 52 to obtain modified gypsum. The second material conveying channel 102 is used to receive the modified gypsum and realize the conveying and discharge of the modified gypsum. The second rotary kiln body 12 is used to achieve heat exchange between the phosphogypsum transported by the first material feeding channel 101 and the modified gypsum transported by the second material feeding channel 102 .

[0036] Specifically, Figure 4 As shown, for the rotary kiln 1, the first rotary kiln body 11 and the second rotary kiln body 12 are coaxially arranged, and the inner wall of the first rotary kiln body 11 and the inner wall of the second rotary kiln body 12 are both provided with a propulsion structure, for example, the inner wall of the first rotary kiln body 11 and the inner wall of the second rotary kiln body 12 are both provided with a propulsion blade 10 extending in a spiral shape.

[0037] The first end of the rotary kiln 1 is provided with a first feeding hopper 13 and a first discharge bin 15, and the second end of the rotary kiln 1 is provided with a second feeding hopper 14 and a second discharge bin 16. The first feeding hopper 13 is used to supply phosphogypsum to the first feeding channel 101. The first rotary kiln body 11 can realize the transportation of phosphogypsum in the first feeding channel 101 when rotating, and discharge the phosphogypsum into the second discharge bin 16 at the second end of the rotary kiln 1, and the flash furnace 2 receives the phosphogypsum discharged from the second discharge bin 16. The second feeding hopper 14 is used to receive the modified gypsum from the calcining furnace 5. The second rotary kiln body 12 can realize the transportation of the modified gypsum in the second feeding channel 102 when rotating, and discharge the modified gypsum into the first discharge bin 15 at the first end of the rotary kiln 1, and the first discharge bin 15 discharges the modified gypsum.

[0038] Among them, the second rotary kiln body 12 can be a heat-conducting kiln body, for example, the heat-conducting kiln body is a steel kiln body or an aluminum alloy kiln body, so that heat exchange between the phosphogypsum transported by the first feed channel 101 and the modified gypsum transported by the second feed channel 102 can be achieved based on the second rotary kiln body 12.

[0039] For the calcining furnace 5, Figure 1 The structure of the middle calcining furnace 5 is a box-type fluidized bed, which is different from Figure 1 The box fluidized bed, Figure 2 The middle calcining furnace 5 is a calcining furnace structure based on a rotatable core. High-temperature fluid is introduced into the core, and phosphogypsum to be calcined is introduced into the feed channel outside the core to achieve dehydration and modification of the phosphogypsum.

[0040] In practical applications, the rotary kiln 1 transports the phosphogypsum to the flash furnace 2. The flash furnace 2 uses the high-temperature flue gas output from the smoke chamber 4 to flash-dry the phosphogypsum to remove most of the attached water in the phosphogypsum, and the attached water content can be less than 10%. The smoke chamber 4 uses the high-temperature flue gas discharged from the external kiln system to heat the heat transfer oil circulating in the first heat conducting member 42. At the same time, the phosphogypsum that has undergone a dehydration treatment is transported to the calcining furnace 5 for calcining. Since the first heat conducting member 42 is connected in series with the second heat conducting member 52 in the calcining furnace 5 to form a closed-loop pipeline system for circulating the heat transfer oil, the heat transfer oil can be used to transfer heat to the second heat conducting member 52, and then the second heat conducting member 52 heats the phosphogypsum to heat the phosphogypsum. The phosphogypsum is converted into modified gypsum such as hemihydrate gypsum and anhydrous gypsum, and the content of modified gypsum can be greater than 60%, and the content of crystal water can be less than 5%. When the modified gypsum is returned to the second feed channel 102 of the rotary kiln 1, the phosphogypsum transported by the first feed channel 101 and the modified gypsum transported by the second feed channel 102 are heat exchanged to realize the drying pretreatment of the phosphogypsum by utilizing the thermal energy of the modified gypsum, and the cooling of the modified gypsum is completed at the same time, and the temperature of the modified gypsum can be reduced to 100°C. The phosphogypsum that has been dried and pretreated is then successively dehydrated and modified in the flash furnace 2 and the calcining furnace 5, and finally cooled and outputted through the rotary kiln 1. This process is repeated to realize the calcination of the phosphogypsum.

[0041] From the above, it can be seen that the phosphogypsum calcining system shown in the present invention fully utilizes the waste heat of high-temperature flue gas to achieve dehydration and modification of phosphogypsum, without the need to use other thermal energy to calcine phosphogypsum. The system has low energy consumption, which not only ensures the normal operation of the phosphogypsum calcining production line, but also achieves the purpose of energy conservation and emission reduction.

[0042] In some embodiments, Figure 5 As shown, the flash furnace 2 has a furnace body 21, and the furnace body 21 is equipped with a flue gas input port 201, a material input port 202, and a flue gas and material discharge port 203. A crushing mechanism 22 is arranged in the furnace body 21, and the crushing mechanism 22 is located at the bottom of the furnace body 21. In actual application, the phosphogypsum output from the rotary kiln 1 enters the furnace body 21 from the material input port 202, and the phosphogypsum is crushed by the crushing mechanism 22. The crushed phosphogypsum contacts with the high-temperature flue gas introduced into the furnace body 21 through the flue gas input port 201, so that the powdered phosphogypsum is flash dried by the high-temperature flue gas. After the phosphogypsum is flash dried, the high-temperature flue gas carries the powdered phosphogypsum and is discharged from the flue gas and material discharge port 203.

[0043] In some embodiments, Figure 1 , Figure 2 and Figure 5As shown, the phosphogypsum calcining system also includes a dust removal device 3, which includes a cyclone separator 31 and a bag dust collector 32; the air inlet of the cyclone separator 31 is connected to the flash furnace 2 to receive the flue gas containing phosphogypsum discharged from the flash furnace 2, the exhaust port of the cyclone separator 31 is connected to the air inlet of the bag dust collector 32, the ash discharge port of the cyclone separator 31 and the ash discharge port of the bag dust collector 32 are respectively connected to the calcining furnace 5; the bag dust collector 32 also has a smoke exhaust port for flue gas discharge.

[0044] It can be understood that the cyclone separator 31 includes a vertically arranged cyclone barrel, the air inlet of the cyclone separator 31 is arranged on the side wall of the cyclone barrel along the tangent direction of the cyclone barrel, the exhaust port of the cyclone separator 31 is arranged at the top of the cyclone barrel, and the ash discharge port of the cyclone separator 31 is arranged at the bottom of the cyclone barrel.

[0045] In actual application, the phosphogypsum discharged from the flash furnace 2 is in powder form. The phosphogypsum enters the cyclone tangentially together with the flue gas and rotates in the cyclone along the inner wall of the cyclone. The phosphogypsum with larger particle size falls to the bottom of the cyclone, and the phosphogypsum with smaller particle size is discharged from the top of the cyclone along with the flue gas and enters the bag dust collector 32. After this part of the dust-containing flue gas is dust-removed by the bag dust collector 32, the clean flue gas is discharged from the exhaust port at the top of the bag dust collector 32, and the phosphogypsum intercepted by the filter bag of the bag dust collector 32 is discharged from the ash discharge port of the bag dust collector 32, and enters the calcining furnace 5 together with the phosphogypsum discharged from the ash discharge port of the cyclone separator 31 for calcination.

[0046] Obviously, in this embodiment, the cyclone separator 31 and the bag filter 32 are used to remove dust from the flue gas containing phosphogypsum discharged from the flash furnace 2, so that the phosphogypsum and the flue gas can be separated and the pollution-free emission of the flue gas can be ensured.

[0047] In some embodiments, Figure 6 , Figure 7 and Figure 8 As shown, the smoke chamber 4 includes a heat-conducting housing 41 and a plurality of first heat-conducting members 42; the heat-conducting housing 41 has a smoke inlet 401, a smoke outlet 402 and a serpentine flow channel 403 formed between the smoke inlet 401 and the smoke outlet 402, and the serpentine flow channel 403 is used to pass high-temperature smoke; Along the flow direction of the high-temperature flue gas in the serpentine flow channel 403, multiple first heat-conducting components 42 are arranged in sequence in the serpentine flow channel 403; a sandwich structure 4100 is provided in the shell wall of the heat-conducting shell 41, and is provided with a fluid inlet and a fluid outlet connected to the sandwich structure 4100; the sandwich structure 4100 is arranged in parallel with the first heat-conducting component 42, and is respectively connected in series with the second heat-conducting component 52 to form a closed-loop pipeline system.

[0048] It is understandable that the heat-conducting shell 41 is configured in a box shape, and the heat-conducting shell 41 can be a metal shell, for example, the heat-conducting shell 41 is made of iron or stainless steel, and the first heat-conducting member 42 and the second heat-conducting member 52 are both tubular metal components.

[0049] The flue gas inlet 401 is configured to receive high-temperature flue gas discharged from the kiln system. The high-temperature flue gas of the kiln system can be generated by the internal kiln calcining system, or by the external kiln system, or by the internal kiln calcining system and the external kiln system. The flue gas outlet 402 of the heat-conducting housing 41 can be configured to communicate with the flue gas input port 201 of the flash furnace 2 through a pipeline to discharge the high-temperature flue gas in the smoke chamber 4 into the flash furnace 2. For example, the temperature of the high-temperature flue gas is 800°C-900°C.

[0050] After entering the serpentine flow channel 403 from the flue gas inlet 401, the high-temperature flue gas from the kiln system flows through each first heat-conducting member 42 in sequence along the extension direction of the serpentine flow channel 403, and exchanges heat with the heat-conducting oil in the first heat-conducting member 42 to heat the heat-conducting oil. The flue gas after heat exchange is discharged from the flue gas outlet 402 and then reaches the flash furnace 2. The serpentine flow channel 403 can be considered as a flow channel that repeatedly bends relative to a certain reference line. Figure 8 Arrows are used to indicate the flow direction of the high-temperature flue gas along the serpentine flow channel 403 .

[0051] At the same time, since the heat-conducting shell 41 has good thermal conductivity, the high-temperature flue gas can also exchange heat with the heat-conducting oil in the sandwich structure 4100 through the heat-conducting shell 41, thereby heating the heat-conducting oil in the sandwich structure 4100.

[0052] As can be seen from the above, the smoke chamber 4 shown in the present invention can guide the high-temperature flue gas to flow along the serpentine flow channel 403 by configuring the structure of the heat-conducting shell 41. In the process of the high-temperature flue gas flowing along the serpentine flow channel 403, the high-temperature flue gas flows through each first heat-conducting component 42 in turn, thereby increasing the heat exchange time of the high-temperature flue gas. The thermal energy of the high-temperature flue gas can be effectively utilized to heat the heat-conducting oil in each first heat-conducting component 42. A part of the heat of the high-temperature flue gas is also transferred to the shell wall of the heat-conducting shell 41, and heat is exchanged with the heat-conducting oil in the sandwich structure 4100 to achieve the heating of this part of the heat-conducting oil. This design effectively improves the recovery and utilization efficiency of the flue gas waste heat.

[0053] In some embodiments, Figure 7 and Figure 8As shown, the heat-conducting shell 41 includes a main shell 411 and a plurality of ash discharge hoppers 412; the smoke inlet 401 and the smoke outlet 402 are respectively arranged on the shell wall of the main shell 411, and a plurality of partitions 4110 are arranged in the main shell 411, and the plurality of partitions 4110 are spaced from each other to define a serpentine flow channel 403 in the main shell 411; the plurality of ash discharge hoppers 412 are respectively arranged on the lower side of the main shell 411 and are connected to the serpentine flow channel 403.

[0054] It can be understood that the multiple partitions 4110 are spaced apart from each other to separate multiple chambers in the main shell 411. However, since any two adjacent ones of the multiple partitions 4110 are staggered along a set direction, the two adjacent chambers are connected to each other, so that the multiple chambers are connected in sequence to form a serpentine flow channel 403.

[0055] The upper end of the ash hopper 412 is connected to the bottom end of the main housing 411, and a discharge port is provided at the lower end of the ash hopper 412. The ash hopper 412 is used to receive dust or particles falling from the serpentine flow channel 403 and discharge the collected dust or particles from the discharge port. The discharge port may be provided with a switch valve, and the switch valve controls the discharge of the dust or particles collected by the ash hopper 412.

[0056] In some embodiments, Figure 8 As shown, the smoke inlet 401 and the smoke outlet 402 are arranged opposite to each other along the length direction of the main shell 411, and a plurality of ash discharge hoppers 412 are arranged side by side along the length direction of the main shell 411; a plurality of partitions 4110 are arranged in sequence along the length direction of the main shell 411, and each partition 4110 is arranged at a position corresponding to the connecting portion of two adjacent ash discharge hoppers 412; wherein, one of the two adjacent partitions 4110 is connected to the connecting portion and is spaced apart from the top wall of the main shell 411, and the other of the two adjacent partitions 4110 is connected to the top wall of the main shell 411 and is spaced apart from the connecting portion.

[0057] It can be understood that since the multiple partitions 4110 are spaced apart from each other and multiple chambers are separated in the main shell 411, the multiple chambers are arranged one by one opposite to the multiple ash buckets 412 and are interconnected. A first heat conductor 42 can be arranged in each chamber, so that the multiple first heat conductors 42 are arranged one by one on the upper side of the multiple ash buckets 412.

[0058] In this way, when the high-temperature flue gas flows through each first heat conducting member 42 in sequence along the extension direction of the serpentine flow channel 403, the high-temperature flue gas will directly flush the surface of each first heat conducting member 42. This design not only ensures the heat exchange effect between the high-temperature flue gas and the heat-conducting oil in the first heat conducting member 42, but also reduces the adhesion of dust on the surface of the first heat conducting member 42, making it convenient to use the ash hopper 412 to collect dust or particulate matter fallen from the corresponding first heat conducting member 42, which has a dust removal effect on the high-temperature flue gas to a certain extent.

[0059] In some embodiments, a first cavity is formed in the shell wall of the main shell 411, and a second cavity is formed in the shell wall of the ash hopper 412. The first cavity and the second cavity are connected to form a sandwich structure 4100; wherein the fluid inlet is connected to the second cavity, and the fluid outlet is connected to the first cavity.

[0060] Specifically, corresponding communication ports are provided between the main shell 411 and each ash discharge hopper 412 to achieve communication between the first cavity and the second cavity.

[0061] Meanwhile, the fluid inlet may be arranged near the bottom of the ash hopper 412, and the fluid outlet may be arranged near the top of the main housing 411. The fluid inlet and the fluid outlet may be configured as flange interfaces so as to be connected with other devices based on the flange interfaces.

[0062] In some embodiments, a third cavity is formed in the partition 4110 , and the third cavity is connected to at least one of the first cavity and the second cavity.

[0063] It can be understood that since the partition 4110 is arranged in the serpentine flow channel 403, the flue gas will directly act on the surface of the partition 4110 during the flow, causing the partition 4110 to have a higher temperature, so that the third cavity corresponding to the partition 4110 can be connected with the sandwich structure 4100. This design not only increases the capacity of the heat transfer oil, but also can effectively utilize the thermal energy of the high-temperature flue gas to heat the heat transfer oil.

[0064] In some embodiments, Figure 7 and Fig. 9 As shown, in order to increase the heat exchange area of ​​the first heat conducting member 42 and prolong the heat exchange time of the heat transfer oil, the first heat conducting member 42 is configured with a plurality of coil units 421, and the plurality of coil units 421 are sequentially connected in series.

[0065] Exemplarily, the plurality of coil units 421 are arranged in sequence from top to bottom, and any two adjacent coil units 421 are connected to each other, so that the plurality of coil units 421 are connected in series.

[0066] Among them, an inlet joint is set at one end of the first heat conductor 42, and an outlet joint is set at the other end. The inlet joint and the outlet joint are both set outside the heat conductive shell 41. The inlet joint and the outlet joint can be flange interfaces so as to be connected with other equipment based on the flange interface.

[0067] In some embodiments, Fig. 9 As shown, in order to reduce the influence of the first heat conducting member 42 on the flow of high temperature flue gas in the serpentine flow channel 403 , the coil unit 421 is coiled in a cylindrical shape to form a flue gas channel 4201 for flue gas to flow inside the coil unit 421 .

[0068] In some embodiments, Figure 7 As shown, the opening area of ​​the smoke inlet 401 is larger than the opening area of ​​the smoke outlet 402. This design can ensure that a large flux of high-temperature smoke enters the serpentine flow channel 403 from the smoke inlet 401, reducing the effect of the setting of the first heat conductor 42 on the flow resistance of the high-temperature smoke, thereby ensuring the flow rate and flow velocity of the high-temperature smoke in the serpentine flow channel 403.

[0069] In some embodiments, Fig.10 and Fig.11 As shown, the calcining furnace 5 includes a rotary furnace body 51 and a second heat-conducting member 52; the second heat-conducting member 52 is cylindrical and is disposed in the rotary furnace body 51, and the second heat-conducting member 52 is configured to rotate synchronously or differentially along the same rotation direction with the rotary furnace body 51; A material channel 501 is formed between the rotary furnace body 51 and the second heat-conducting member 52, and the material channel 501 is used to realize the transportation of the phosphogypsum that has been dehydrated once by the flash furnace 2; the second heat-conducting member 52 is used to pass heat-conducting oil, and the second heat-conducting member 52 is used to realize heat exchange between the heat-conducting oil and the phosphogypsum, so as to perform a secondary dehydration treatment on the phosphogypsum.

[0070] It can be understood that the rotary furnace body 51 is equipped with an upper hopper 55 and a discharge bin 56. The upper hopper 55 is arranged at the kiln head of the rotary furnace body 51, and the upper hopper 55 receives the phosphogypsum from the flash furnace 2 and transports the phosphogypsum to the material channel 501; the discharge bin 56 is arranged at the kiln tail of the rotary furnace body 51, and is configured to collect the modified gypsum obtained after secondary dehydration treatment output from the material channel 501.

[0071] The rotary furnace body 51 is arranged at an incline, for example, the rotation axis of the rotary furnace body 51 is arranged at an acute angle relative to the horizontal plane, the rotary furnace body 51 can rotate around its rotation axis, and the material channel 501 extends along the direction of the rotation axis. This design ensures that the phosphogypsum can move from the kiln head to the kiln tail of the calcining furnace 5 along the material channel 501 under the action of its own gravity.

[0072] At the same time, the second heat-conducting member 52 can be fixedly arranged in the rotary furnace body 51 so that the second heat-conducting member 52 and the rotary furnace body 51 rotate synchronously; the second heat-conducting member 52 can also be rotatably arranged in the rotary furnace body 51 under the drive of the driving device so that the second heat-conducting member 52 can rotate along the same rotation direction with the rotary furnace body 51 at a differential speed. The rotary furnace body 51 has a rotation speed greater than the rotation speed of the second heat-conducting member 52.

[0073] The calcining furnace 5 shown in the present invention forms a material channel 501 between the rotary furnace body 51 and the second heat-conducting member 52 by arranging the second heat-conducting member 52 in the rotary furnace body 51, so that the high-temperature heat-conducting oil flows along the fluid channel in the second heat-conducting member 52, and the phosphogypsum input from the upper hopper 55 flows along the material channel 501. The phosphogypsum and the heat-conducting oil are isolated from each other, and a partition-type heat exchange can be performed based on the second heat-conducting member 52, so as to realize the secondary dehydration treatment of the phosphogypsum. Fig.11 The solid arrows indicate the flow direction of the phosphogypsum, and the dotted arrows indicate the flow direction of the heat transfer oil.

[0074] As can be seen from the above, the calcining furnace 5 shown in this embodiment can use the heat of the heat transfer oil to perform secondary dehydration treatment on the phosphogypsum under normal pressure. The modified gypsum obtained after the secondary dehydration can be directly collected in the discharge bin 56. The whole set of dehydration work is carried out under normal pressure, which can effectively avoid the overflow of dried materials at the head and tail of the kiln during the operation of the calcining furnace 5, thereby effectively avoiding air pollution in the working environment of the calcining furnace 5.

[0075] In some embodiments, Fig.11 As shown, a scoop plate 511 is provided on the inner wall of the rotary furnace body 51 , and the scoop plate 511 extends toward the peripheral wall of the second heat-conducting member 52 . The scoop plate 511 is used to move the phosphogypsum along the circumferential direction of the second heat-conducting member 52 during the rotation of the rotary furnace body 51 .

[0076] It is understandable that the first side of the scoop plate 511 is connected to the inner wall of the rotary furnace body 51 , the second side of the scoop plate 511 extends to the peripheral wall of the second heat-conducting member 52 , and a gap is left between the second side of the scoop plate 511 and the peripheral wall of the second heat-conducting member 52 .

[0077] Since the rotary furnace body 51 is arranged at an angle, during the rotation of the rotary furnace body 51, the powdered phosphogypsum will move downward along the material channel 501 between the rotary furnace body 51 and the second heat-conducting member 52 under the action of its own gravity, and the phosphogypsum also has a rotation tendency lagging behind the rotary furnace body 51 in the circumferential direction. Since the scoop plate 511 is arranged on the inner wall of the rotary furnace body 51, during the rotation of the scoop plate 511 along with the rotary furnace body 51, the scoop plate 511 will move the phosphogypsum along the circumferential direction of the second heat-conducting member 52, thereby ensuring that the phosphogypsum fully receives the heat from the second heat-conducting member 52, thereby improving the dehydration treatment effect of the phosphogypsum.

[0078] In some embodiments, Fig.11 As shown, the scooping plate 511 is extended along the axial direction of the rotary furnace body 51. This design can improve the material-moving effect of the scooping plate 511 on the powdered raw materials along the circumferential direction.

[0079] Exemplarily, a plurality of scoop plates 511 are provided, and the plurality of scoop plates 511 are sequentially spaced apart and arranged on the inner wall of the rotary furnace body 51 along the circumferential direction.

[0080] Exemplarily, the first side edge of the scoop plate 511 is connected to the inner wall of the rotary furnace body 51, the second side edge of the scoop plate 511 extends to the peripheral wall of the second heat-conducting member 52, the first side edge and the second side edge of the scoop plate 511 both extend along the axial direction of the rotary furnace body 51, and the plane where the scoop plate 511 is located coincides with or is arranged at an angle to the plane formed by the first side edge of the scoop plate 511 and the rotation axis of the rotary furnace body 51.

[0081] In some embodiments, the scoop plate 511 is extended along a spiral trajectory relative to the rotation axis of the rotary furnace body 51. This design ensures that the scoop plate 511 drives the powdered raw material to move circumferentially along the second heat conductor 52, and can also utilize the spiral conveying characteristics of the scoop plate 511 to drive the phosphogypsum to move along the material channel 501 toward one side of the kiln tail of the calcining furnace 5.

[0082] In some embodiments, Fig.12 and Fig.13 As shown, the second heat conducting member 52 includes a heat conducting cylinder 521, which is extended along the rotation axis of the rotary furnace body 51. The cross-section of the heat conducting cylinder 521 along a plane perpendicular to the rotation axis is star-shaped, and heat conducting oil is passed into the heat conducting cylinder 521.

[0083] It is understandable that, in order to ensure the heat exchange effect, the heat-conducting cylinder 521 is made of metal material, for example, the heat-conducting cylinder 521 is a steel cylinder. At the same time, by designing the cross-sectional shape of the heat-conducting cylinder 521 to be star-shaped, it can be ensured that the peripheral wall of the heat-conducting cylinder 521 forms a plurality of material grooves arranged along the circumferential direction, each material groove can support a part of the phosphogypsum, thereby increasing the heat exchange area of ​​the heat-conducting cylinder 521, which is conducive to improving the dehydration treatment effect of the phosphogypsum.

[0084] Exemplarily, the cross-sectional shape of the heat-conducting cylinder 521 may be a four-pointed star, a five-pointed star, or a six-pointed star, wherein the cross-sectional shape of the fluid channel in the heat-conducting cylinder 521 matches the appearance contour of the cross-sectional shape of the heat-conducting cylinder 521 .

[0085] Furthermore, if Fig.12 As shown, adapters 522 are formed at both ends of the heat-conducting cylinder 521 . The adapters 522 are communicated with the fluid channel in the heat-conducting cylinder 521 . The adapters 522 are also configured to be rotatably connected to a fixed pipeline.

[0086] It is understandable that both ends of the heat-conducting cylinder 521 are closed and connected to the corresponding adapter 522. The adapter 522 can be a sealed joint. The adapter 522 can be rotatably connected to the fixed pipeline while also achieving a sealed connection. This design ensures that there is no leakage of high-temperature fluid at the connection between the heat-conducting cylinder 521 and the fixed pipeline, and meets the rotation requirement of the heat-conducting cylinder 521 relative to the fixed pipeline.

[0087] In some embodiments, Fig.12 and Fig.14 As shown, the second heat conducting member 52 further includes a central tube 523 , which is inserted into the heat conducting cylinder 521 , and the gap between the inner wall of the heat conducting cylinder 521 and the peripheral wall of the central tube 523 is used to pass heat conducting oil.

[0088] It is understandable that since the heat transfer oil is only distributed in the gap between the heat transfer cylinder 521 and the central tube 523, this design can ensure the heat exchange effect of the second heat transfer component 52 while reducing the weight of the second heat transfer component 52 as much as possible, thereby reducing the workload of the calcining furnace 5.

[0089] In some embodiments, Fig.11 As shown, the peripheral wall of the heat-conducting cylinder 521 is connected to the inner wall of the rotary furnace body 51. For example, the peripheral wall of the heat-conducting cylinder 521 is connected to the inner wall of the rotary furnace body 51 through a plurality of discretely distributed points. This design not only ensures the smoothness of the material channel 501 between the rotary furnace body 51 and the second heat-conducting member 52, but also enables the second heat-conducting member 52 to rotate synchronously with the rotary furnace body 51 in the same direction of rotation.

[0090] In some embodiments, the heat-conducting cylinder 521 and the rotary furnace body 51 may also be disposed separately from each other, and the heat-conducting cylinder 521 may be rotatably disposed in the rotary furnace body 51 .

[0091] Specifically, both ends of the heat-conducting cylinder 521 extend out of the rotary furnace body 51 and are rotatably disposed on a rotary bracket. At least one end of the heat-conducting cylinder 521 is connected to a driving device, so that under the drive of the driving device, the heat-conducting cylinder 521 can be rotatably disposed in the rotary furnace body 51, and the second heat-conducting member 52 can be differentially rotated along with the rotary furnace body 51 in the same rotational direction.

[0092] In some embodiments, Fig.10 and Fig.11 As shown, in order to facilitate the rotary motion of the rotary furnace body 51, the rotary furnace body 51 is provided with a rotary support 54 and a rotary drive assembly 53; The rotary furnace body 51 is cylindrical and rotatably disposed on a rotary support 54. The rotary drive assembly 53 is connected to the rotary furnace body 51 to drive the rotary furnace body 51 to rotate on the rotary support 54. The first end of the rotary furnace body 51 is configured to be rotatably connected to the kiln head support, and the second end of the rotary furnace body 51 is rotatably connected to the discharge bin 56. The second heat-conducting member 52 is penetrated in the rotary furnace body 51, and both ends of the second heat-conducting member 52 extend out of the rotary furnace body 51.

[0093] Specifically, two swivel supports 54 are provided, and the two swivel supports 54 are spaced apart from each other, one of the swivel supports 54 provides swivel support for the first end of the swivel furnace body 51 at a first height, and the other swivel support 54 provides swivel support for the second end of the swivel furnace body 51 at a second height, and the first height is greater than the second height. This design ensures that the swivel furnace body 51 is rotatably arranged on the swivel supports 54 in an inclined manner. Each swivel support 54 provides swivel support for the swivel furnace body 51 through two supporting wheels arranged side by side.

[0094] like Fig.11 As shown, the rotary drive assembly 53 includes a drive motor 531 , a gear assembly 532 and a ring gear 533 ; the drive motor 531 is transmission-connected to the ring gear 533 via the gear assembly 532 , and the ring gear 533 is sleeved on the peripheral wall of the rotary furnace body 51 .

[0095] Specifically, the driving motor 531 may be a reduction motor, the gear assembly 532 includes a first gear and a second gear, the output end of the driving motor 531 is connected to the first gear, the first gear and the second gear are meshed, and the second gear is meshed with the ring gear 533. The gear ratio of the first gear and the second gear can be set according to actual needs.

[0096] Thus, when the driving motor 531 starts working, the driving motor 531 drives the first gear to rotate, the first gear drives the second gear to rotate, the second gear drives the ring gear 533 to rotate, and the ring gear 533 drives the rotary furnace body 51 to rotate on the rotary support 54.

[0097] In some embodiments, Figure 1 , Figure 2 and Figure 3 As shown, the phosphogypsum calcining system further includes a first conveying line 6 , which is disposed between the rotary kiln 1 and the flash furnace 2 to convey the phosphogypsum discharged from the first feeding channel 101 of the rotary kiln 1 to the feed port of the flash furnace 2 .

[0098] At the same time, the phosphogypsum calcining system further includes a second conveying line 7 , which is arranged between the calcining furnace 5 and the rotary kiln 1 to convey the modified gypsum output from the calcining furnace 5 to the second material conveying channel 102 of the rotary kiln 1 .

[0099] Wherein, the first conveyor line 6 and the second conveyor line 7 can both be belt conveyor lines or chain plate conveyor lines.

[0100] In a second aspect, an embodiment of the present invention further provides a method for harmless treatment of phosphogypsum, comprising: using the phosphogypsum calcination system with waste heat recovery as described above to sequentially preheat, dehydrate, dry, calcine and cool the phosphogypsum.

[0101] Specifically, the present invention utilizes the first feed channel of the rotary kiln to transport phosphogypsum, performs heat exchange between the phosphogypsum transported by the first feed channel and the modified gypsum transported by the second feed channel, realizes drying pretreatment of the phosphogypsum by utilizing the thermal energy of the modified gypsum, then utilizes a flash furnace to perform a primary dehydration and drying treatment on the phosphogypsum, then utilizes a calcining furnace to perform a secondary dehydration treatment on the phosphogypsum, that is, realizes calcination treatment of the phosphogypsum, and the modified gypsum obtained after two dehydrations is returned to the second feed channel of the rotary kiln, and then performs heat exchange between the phosphogypsum transported by the first feed channel and the modified gypsum transported by the second feed channel, thereby realizing cooling and outputting of the modified gypsum.

[0102] Since the harmless treatment method for phosphogypsum shown in the present embodiment is based on the above-mentioned phosphogypsum calcining system with waste heat recovery and utilization, and the specific structure of the phosphogypsum calcining system with waste heat recovery and utilization refers to the above-mentioned embodiment, the harmless treatment method for phosphogypsum of the present embodiment includes all the technical solutions of the above-mentioned embodiment, and therefore has at least all the beneficial effects achieved by all the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phosphogypsum calcining system with waste heat recovery, characterized in that: include: Rotary kilns, flash furnaces, smoke chambers and calciners; The rotary kiln comprises a first rotary kiln body and a second rotary kiln body; the first rotary kiln body is rotatably sleeved on the outer side of the second rotary kiln body, and the second rotary kiln body is rotatably arranged; a first material conveying channel is formed between the first rotary kiln body and the second rotary kiln body, and a second material conveying channel is formed inside the second rotary kiln body; the first material conveying channel of the rotary kiln is connected to the flash furnace, the flash furnace is respectively connected to the smoke chamber and the calcining furnace, and the calcining furnace is connected to the second material conveying channel; The first feeding channel is used to transport phosphogypsum, the flash furnace is configured to receive high-temperature flue gas and phosphogypsum output from the first feeding channel, the flash furnace uses the high-temperature flue gas output from the smoke chamber to perform a primary dehydration treatment on the phosphogypsum, and transports the primary dehydrated phosphogypsum to the calcining furnace; A first heat-conducting member is provided in the smoke chamber, and a second heat-conducting member is provided in the calcining furnace. The first heat-conducting member and the second heat-conducting member are connected in series to form a closed-loop pipeline system for circulating heat-conducting oil. The smoke chamber uses the high-temperature flue gas discharged from the kiln system to heat the heat-conducting oil flowing through the first heat-conducting member. The calcining furnace uses the second heat-conducting member to perform secondary dehydration treatment on the phosphogypsum to obtain modified gypsum. The second feed channel is used to receive the modified gypsum and realize the transportation and discharge of the modified gypsum. The second rotary kiln body is used to achieve heat exchange between the phosphogypsum transported by the first material feeding channel and the modified gypsum transported by the second material feeding channel.

2. The waste heat recovery and utilization phosphogypsum calcining system according to claim 1 is characterized in that: The inner wall of the first rotary kiln body and the inner wall of the second rotary kiln body are both provided with propulsion blades extending in a spiral shape.

3. The waste heat recovery and utilization phosphogypsum calcining system according to claim 1 is characterized in that: Also included is a dust removal device, which includes a cyclone separator and a bag dust collector; The air inlet of the cyclone separator is connected to the flash furnace to receive the flue gas containing the phosphogypsum discharged from the flash furnace. The exhaust port of the cyclone separator is connected to the air inlet of the bag dust collector. The ash discharge port of the cyclone separator and the ash discharge port of the bag dust collector are respectively connected to the calcining furnace; the bag dust collector also has a smoke exhaust port for flue gas discharge.

4. The waste heat recovery and utilization phosphogypsum calcining system according to claim 1 is characterized in that: The smoke chamber comprises a heat-conducting housing and a plurality of the first heat-conducting members; The heat-conducting housing has a smoke inlet, a smoke outlet, and a serpentine flow channel formed between the smoke inlet and the smoke outlet, and the serpentine flow channel is used to pass the high-temperature smoke; Along the flow direction of the high-temperature flue gas in the serpentine flow channel, a plurality of the first heat-conducting members are sequentially arranged in the serpentine flow channel; a sandwich structure is arranged in the shell wall of the heat-conducting shell, and a fluid inlet and a fluid outlet connected to the sandwich structure are configured; The sandwich structure is arranged in parallel with the first heat-conducting member, and is respectively connected in series with the second heat-conducting member to form the closed-loop pipeline system; The flue gas inlet is configured to receive high-temperature flue gas discharged from the kiln system, and the flue gas outlet is configured to communicate with the flash furnace.

5. The waste heat recovery and utilization phosphogypsum calcining system according to claim 4 is characterized in that: The heat-conducting housing comprises a main housing and a plurality of ash discharge hoppers; The smoke inlet and the smoke outlet are respectively arranged on the shell wall of the main shell, and a plurality of partitions are arranged in the main shell. The plurality of partitions are spaced from each other to define the serpentine flow channel in the main shell; a plurality of ash discharge hoppers are respectively arranged on the lower side of the main shell and are connected to the serpentine flow channel.

6. The waste heat recovery and utilization phosphogypsum calcining system according to claim 1 is characterized in that: The calcining furnace comprises a rotary furnace body and the second heat conducting member; The second heat-conducting member is cylindrical and is disposed inside the rotary furnace body. The second heat-conducting member is configured to rotate synchronously or differentially along the same rotation direction as the rotary furnace body. A material channel is formed between the rotary furnace body and the second heat-conducting member, and the material channel is used to transport the phosphogypsum that has been subjected to a primary dehydration treatment in the flash furnace; The second heat-conducting member is used for passing heat-conducting oil, and the second heat-conducting member is used for realizing heat exchange between the heat-conducting oil and the phosphogypsum, so as to perform secondary dehydration treatment on the phosphogypsum.

7. The waste heat recovery and utilization phosphogypsum calcining system according to claim 6 is characterized in that: A scooping plate is provided on the inner wall of the rotary furnace body, and the scooping plate extends toward the peripheral wall of the second heat-conducting member. The scooping plate is used to move the phosphogypsum along the circumferential direction of the second heat-conducting member during the rotation of the rotary furnace body.

8. The waste heat recovery and utilization phosphogypsum calcining system according to claim 6, characterized in that: The second heat-conducting member comprises a heat-conducting cylinder, which is extended along the rotary axis of the rotary furnace body. The cross-section of the heat-conducting cylinder along a plane perpendicular to the rotary axis is star-shaped, and the heat-conducting oil is passed into the heat-conducting cylinder.

9. The waste heat recovery and utilization phosphogypsum calcining system according to claim 8, characterized in that: The second heat-conducting member further comprises a central tube, which is inserted into the heat-conducting cylinder. The gap between the inner wall of the heat-conducting cylinder and the peripheral wall of the central tube is used for passing the heat-conducting oil.

10. The phosphogypsum calcining system for waste heat recovery according to any one of claims 1 to 9, characterized in that: It also includes a first conveying line, which is arranged between the rotary kiln and the flash furnace to convey the phosphogypsum discharged from the first feeding channel of the rotary kiln to the feeding port of the flash furnace; And / or, it also includes a second conveying line, which is arranged between the calcining furnace and the rotary kiln to convey the modified gypsum output from the calcining furnace to the second material conveying channel of the rotary kiln.

11. A method for harmless treatment of phosphogypsum, characterized in that: include: The phosphogypsum calcining system with waste heat recovery as described in any one of claims 1 to 10 is used to sequentially preheat, dehydrate, dry, calcine and cool the phosphogypsum.

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