System and process for calcining ardealite by using waste heat of high-temperature flue gas of calcining kiln

Abstract

The invention provides a system and a process for calcining ardealite by using waste heat of high-temperature flue gas of a calcining kiln. The system for calcining ardealite by using waste heat of high-temperature flue gas of the calcining kiln comprises a calcining device, a smoke chamber, a smoke chamber waste heat calcining device and a flue gas purifying device, the calcining device comprises a calcining kiln, the smoke chamber waste heat calcining device comprises a smoke drying kiln, the smoke purifying device comprises a bag-type dust collector, and the smoke chamber is communicated with the calcining kiln; the flue gas drying kiln comprises a basic calcining kiln and a jacketed calcining kiln, the jacketed calcining kiln sleeves the outer side of the basic calcining kiln, the jacketed calcining kiln is connected with the basic calcining kiln, and the basic calcining kiln is used for calcining phosphogypsum; each of the basic calcining kiln and the jacket calcining kiln is provided with a chamber, one end of the basic calcining kiln is communicated with one end of the jacket calcining kiln, one chamber is communicated with the smoke chamber, the other chamber is communicated with the bag-type dust collector, and smoke in the smoke chamber sequentially passes through the two chambers and then enters the bag-type dust collector. The waste heat utilization efficiency of the flue gas can be improved.

Description

Technical Field

[0001] This application relates to the technical field of phosphogypsum processing, and in particular to a system and process for calcining phosphogypsum with the waste heat of high-temperature flue gas from a calcining kiln. Background Art

[0002] A ceramsite calcining kiln includes a kiln body, a feeding mechanism, and a discharging mechanism. The feeding mechanism can add ceramsite into the kiln body, the kiln body calcines the ceramsite, and the discharging mechanism collects the calcined ceramsite. When the ceramsite calcining kiln is calcining, flue gas will be generated. The flue gas discharged from the ceramsite calcining kiln generally needs to be first subjected to dust removal treatment in a smoke chamber, and then subjected to flue gas dust removal and flue gas purification treatment in a bag filter before being discharged into the atmosphere. The bag filter requires that the temperature of the incoming flue gas does not exceed 200°C, while the temperature of the high-temperature flue gas is still as high as 250°C - 550°C after ash reduction in the smoke chamber. Directly introducing the high-temperature flue gas into the bag filter will damage the bag filter, and the waste heat of the high-temperature flue gas will also be wasted.

[0003] In the related art, generally, the high-temperature flue gas is introduced into a flue gas drying kiln to directly contact with phosphogypsum, so as to calcine the phosphogypsum to recover and utilize the waste heat of the high-temperature flue gas and reduce the temperature of the high-temperature flue gas. However, in the related art, the contact time between the flue gas and the flue gas drying kiln is short, resulting in low waste heat utilization efficiency of the flue gas. Summary of the Invention

[0004] In order to improve the waste heat utilization efficiency of the flue gas, this application provides a system and process for calcining phosphogypsum with the waste heat of high-temperature flue gas from a calcining kiln.

[0005] In the first aspect, this application provides a system for calcining phosphogypsum with the waste heat of high-temperature flue gas from a calcining kiln, adopting the following technical solution: A system for calcining phosphogypsum with the waste heat of high-temperature flue gas from a calcining kiln includes a calcining device, a smoke chamber, a smoke chamber waste heat calcining device, and a flue gas purification device; the calcining device includes a calcining kiln for calcining ceramsite; the smoke chamber waste heat calcining device includes a flue gas drying kiln, and the flue gas purification device includes a bag filter; the smoke chamber is connected to the calcining kiln, and the smoke chamber performs dust removal treatment on the flue gas generated by the calcining kiln; The flue gas drying kiln includes a basic calcining kiln and a jacket calcining kiln. The jacket calcining kiln is sleeved outside the basic calcining kiln, and the jacket calcining kiln is connected to the basic calcining kiln. The basic calcining kiln is used for calcining phosphogypsum; both the basic calcining kiln and the jacket calcining kiln are provided with chambers. The basic calcining kiln and the jacket calcining kiln are connected at one end. One of the chambers is connected to the smoke chamber, and the other chamber is connected to the bag filter. The flue gas of the smoke chamber passes through the two chambers in sequence and then enters the bag filter, and the bag filter performs dust removal treatment on the passing flue gas.

[0006] By adopting the above technical solution, the high-temperature flue gas generated by the calcination kiln is first subjected to preliminary dust removal treatment in the smoke chamber, and then enters the two chambers in sequence and is discharged after dust removal by the bag filter. The jacketed calcination kiln is sleeved outside the basic calcination kiln, effectively extending the residence time and path of the flue gas in the system, making full use of the heat of the flue gas, and improving the waste heat utilization efficiency. Moreover, the basic calcination kiln and the jacketed calcination kiln can absorb most of the heat in the flue gas, can perform secondary cooling on the flue gas, which is beneficial to dust removal by the bag filter and reduces the damage of the high-temperature flue gas to the bag filter.

[0007] Optionally, it further includes a phosphogypsum conveying assembly, and the phosphogypsum conveying assembly drives the phosphogypsum to move in the basic calcination kiln, so that the phosphogypsum and the flue gas move in opposite directions in the basic calcination kiln.

[0008] By adopting the above technical solution, the phosphogypsum conveying assembly can drive the phosphogypsum to move in the basic calcination kiln, so that the phosphogypsum and the flue gas move in opposite directions in the chamber. It not only increases the contact time and area between the phosphogypsum and the flue gas, but also improves the heat exchange efficiency, enables the waste heat of the high-temperature flue gas to be fully utilized, effectively reduces the temperature of the flue gas, and at the same time ensures that the phosphogypsum is fully heated, improving the calcination quality of the phosphogypsum.

[0009] Optionally, the smoke chamber is communicated with the basic calcination kiln, and the jacketed calcination kiln is communicated with the bag filter.

[0010] By adopting the above technical solution, the flue gas is first subjected to dust removal treatment in the smoke chamber and then directly enters the basic calcination kiln, and the heat in the flue gas is fully utilized to heat the phosphogypsum, improving the waste heat utilization efficiency. Subsequently, the flue gas enters the jacketed calcination kiln, ensuring that the flue gas enters the bag filter after sufficient cooling, reducing the damage of high temperature to the bag filter and extending the service life of the equipment.

[0011] Optionally, a guiding wall is arranged on the outer wall of the basic calcination kiln, and the guiding wall is inclined. The dust in the flue gas in the jacketed calcination kiln deposits on the guiding wall; a guiding ring is connected to the end of the jacketed calcination kiln, and the outer wall of the guiding ring is inclined. The guiding wall guides the dust to the guiding ring, and the guiding ring guides the dust into the basic calcination kiln.

[0012] By adopting the above technical solution, during the process of the flue gas flowing through the jacketed calcination kiln, the dust in the flue gas will deposit on the guiding wall. Due to the inclined arrangement of the guiding wall, the dust can be effectively guided to the guiding ring, and the guiding ring then guides the dust into the basic calcination kiln, reducing the accumulation of dust in the jacketed calcination kiln and affecting the heat exchange efficiency, and at the same time reducing the burden on the bag filter, improving the overall operation efficiency and reliability of the system.

[0013] Optionally, the ends of the jacket calcination kiln and the basic calcination kiln are rotatably connected with a first rotary joint, and the first rotary joint is provided with an inner ring and an outer ring; the basic calcination kiln communicates with the inner ring of the first rotary joint, a communicating pipe is connected between the inner ring of the first rotary joint and the smoke chamber, the jacket calcination kiln communicates with the outer ring of the first rotary joint, and an exhaust pipe is connected between the outer ring of the first rotary joint and the bag filter; the exhaust pipe is provided with a bent section, dust in the flue gas is deposited on the bent section of the exhaust pipe, and the bent section of the exhaust pipe guides the dust into the jacket calcination kiln.

[0014] By adopting the above technical solution, the flue gas enters the bag filter after passing through the outer ring of the first rotary joint and the exhaust pipe from the jacket calcination kiln. The dust generated by calcining phosphogypsum in the flue gas is deposited on the bent section of the exhaust pipe and guided into the jacket calcination kiln, effectively reducing the dust content in the flue gas and improving the working life and dust removal efficiency of the bag filter. At the same time, the bent section of the exhaust pipe helps to further reduce the flow velocity of the flue gas, which is beneficial to the deposition of the flue gas in the bent section of the exhaust pipe.

[0015] Optionally, the smoke chamber communicates with the jacket calcination kiln, and the basic calcination kiln communicates with the bag filter.

[0016] By adopting the above technical solution, the flue gas enters the bag filter after passing through the jacket calcination kiln and the basic calcination kiln in sequence, improving the utilization efficiency of the waste heat of the flue gas. After the flue gas is cooled twice by the jacket calcination kiln and the basic calcination kiln, the temperature of the flue gas can be effectively reduced, ensuring the safe operation of the bag filter.

[0017] Optionally, the two ends of the jacket calcination kiln are respectively rotatably connected with a second rotary joint and a third rotary joint. The second rotary joint is provided with an outer ring and an inner ring. The jacket calcination kiln communicates with the outer ring of the second rotary joint, and a communicating pipe is connected between the smoke chamber and the outer ring of the second rotary joint; the jacket calcination kiln communicates with the basic calcination kiln through the third rotary joint, the basic calcination kiln communicates with the inner ring of the second rotary joint, and an exhaust pipe is connected between the bag filter and the inner ring of the second rotary joint; the exhaust pipe is provided with a bent section, dust in the flue gas is deposited on the bent section of the exhaust pipe, and the bent section of the exhaust pipe guides the dust into the basic calcination kiln.

[0018] By adopting the above technical solution, the jacket calcination kiln communicates with the outer ring of the second rotary joint, and a communicating pipe is connected between the smoke chamber and the outer ring of the second rotary joint, ensuring that the high-temperature flue gas can smoothly enter the jacket calcination kiln from the smoke chamber. The dust generated by calcining phosphogypsum in the flue gas is deposited on the bent section of the exhaust pipe and guided into the basic calcination kiln, effectively reducing the dust content in the flue gas and improving the working efficiency and life of the subsequent bag filter.

[0019] Optionally, the phosphogypsum conveying assembly includes a support table, support rollers and a rotation driving source; the support rollers are rotatably connected to the support table, a plurality of the support rollers are provided, and the plurality of support rollers carry the jacket calcining kiln, and the basic calcining kiln is inclined; the rotation driving source is connected to the support table, and the rotation driving source drives the support rollers to rotate, so that the jacket calcining kiln and the basic calcining kiln rotate.

[0020] By adopting the above technical solution, the rotation driving source drives the support rollers to rotate, so that the jacket calcining kiln and the basic calcining kiln rotate synchronously. Since the basic calcining kiln is inclined, it can make the phosphogypsum move slowly in the basic calcining kiln, which is beneficial to the effective contact between the phosphogypsum and the flue gas, and improves the waste heat utilization efficiency.

[0021] Optionally, a spiral blade is connected inside the basic calcining kiln, and the flue gas inside the basic calcining kiln flows along the spiral blade.

[0022] By adopting the above technical solution, the spiral blade inside the basic calcining kiln can guide the flue gas to flow along a spiral path, extend the residence time of the flue gas in the basic calcining kiln, reduce the flow velocity of the flue gas, increase the contact area and time between the flue gas and the phosphogypsum, and improve the waste heat utilization efficiency. The rotation driving source makes the basic calcining kiln rotate, which can drive the spiral blade to rotate, and the spiral blade makes the phosphogypsum move from one end to the other end in the basic calcining kiln.

[0023] In a second aspect, the present application also provides a process for calcining phosphogypsum with the waste heat of the high-temperature flue gas of a calcining kiln, using the above-mentioned system for calcining phosphogypsum with the waste heat of the high-temperature flue gas of a calcining kiln, including the following steps: The flue gas treated in the smoke chamber passes through two chambers in sequence and then enters the bag filter. The rotation driving source drives the support rollers to rotate, so that the basic calcining kiln and the jacket calcining kiln rotate, driving the phosphogypsum to move in the basic calcining kiln, and the flue gas and the phosphogypsum move in opposite directions in the basic calcining kiln; the bag filter performs dust removal treatment on the flue gas and discharges it up to standard.

[0024] By adopting the above technical solution, the waste heat of the high-temperature flue gas can be effectively utilized to calcine the phosphogypsum, improving the waste heat utilization rate and reducing the energy consumption. The basic calcining kiln and the jacket calcining kiln can cool the flue gas twice, reducing the heat of the flue gas and reducing the damage to the bag filter by the flue gas, ensuring the stable operation of the system and the environmental protection up-to-standard discharge.

[0025] In summary, the present application includes at least one of the following beneficial effects: 1. The jacket calcination kiln is sleeved outside the basic calcination kiln, which improves the utilization efficiency of the waste heat of the flue gas. By extending the residence time of the flue gas in the system, more heat can be transferred to the phosphogypsum, effectively reducing the flue gas temperature and reducing the damage of high temperature to the bag filter. 2. The bent section of the exhaust pipe can reduce the flow rate of the flue gas, causing the dust in the flue gas to settle on the bent section of the exhaust pipe and the guide wall. The guide wall guides the dust to the guide ring. The outer wall of the guide ring is inclined, and the guide ring then guides the dust into the basic calcination kiln, reducing the dust content in the flue gas, reducing the burden on the subsequent bag filter, and improving the operation stability and reliability of the entire system. 3. The rotation drive source drives the support roller to rotate, causing the basic calcination kiln and the jacket calcination kiln to rotate synchronously, thereby driving the spiral blade to move, realizing the uniform distribution and movement of the phosphogypsum in the basic calcination kiln; the spiral blade can reduce the flow rate of the flue gas, which is beneficial to the contact between the flue gas and the phosphogypsum, and further improves the heat exchange efficiency. Description of the Drawings

[0026] Figure 1 is the overall structural schematic diagram of the phosphogypsum calcination system with high-temperature flue gas waste heat in Embodiment 1 of the present application; Figure 2 is the sectional structural schematic diagram of the flue gas drying kiln in Embodiment 1 of the present application; Figure 3 is the sectional structural schematic diagram of the first rotating joint in Embodiment 1 of the present application; Figure 4 is the overall structural schematic diagram of the phosphogypsum calcination system with high-temperature flue gas waste heat in Embodiment 2 of the present application; Figure 5 is the sectional structural schematic diagram of the flue gas drying kiln in Embodiment 3 of the present application; Figure 6 is the overall structural schematic diagram of the phosphogypsum calcination system with high-temperature flue gas waste heat in Embodiment 4 of the present application; Figure 7 is the sectional structural schematic diagram of the flue gas drying kiln in Embodiment 4 of the present application.

[0027] Description of reference numerals: 1, calcination kiln; 11, kiln body; 12, feeding mechanism; 13, discharging mechanism; 2, smoke chamber; 3, flue gas drying kiln; 31, basic calcination kiln; 32, jacketed calcination kiln; 33, guiding wall; 34, feeding assembly; 341, feeding bin; 342, feeding conveyor; 343, first switching valve; 344, feeding pipe; 35, discharging assembly; 351, discharging pipe; 352, second switching valve; 353, discharging bin; 354, discharging conveyor; 36, first rotating joint; 37, second rotating joint; 38, third rotating joint; 39, guiding ring; 4, phosphogypsum conveying assembly; 41, supporting platform; 42, supporting roller; 43, rotating drive source; 44, spiral blade; 5, connecting pipe; 6, exhaust pipe; 7, bag filter; 8, separator. Detailed implementation manners

[0028] The following Figures 1 to 7 is a further detailed description of the present application.

[0029] Embodiment 1: Embodiment 1 of the present application provides a system and process for calcining phosphogypsum with waste heat of high-temperature flue gas from a calcination kiln.

[0030] Referring to Figure 1 , the system for calcining phosphogypsum with waste heat of high-temperature flue gas from the calcination kiln 1 includes a calcination device, a smoke chamber 2, a waste heat calcination device for the smoke chamber 2, a phosphogypsum conveying assembly 4, and a flue gas purification device. The calcination device includes a calcination kiln 1, the waste heat calcination device for the smoke chamber 2 includes a flue gas drying kiln 3, and the flue gas purification device includes a separator 8 and a bag filter 7. The calcination kiln 1 specifically adopts a rotary kiln. The calcination kiln 1 includes a kiln body 11, a feeding mechanism 12, and a discharging mechanism 13. The feeding mechanism 12 can add ceramsite into the kiln body 11. The kiln body 11 is used for calcining ceramsite, and the discharging mechanism 13 collects the ceramsite after being calcined in the kiln body 11. The kiln body 11 is communicated with the smoke chamber 2. After the calcination kiln 1 calcines ceramsite, flue gas is generated, and the flue gas enters the smoke chamber 2 for dust removal treatment.

[0031] Referring to Figure 1 , the phosphogypsum conveying assembly 4 includes a supporting platform 41, supporting rollers 42, and a rotating drive source 43. The supporting platform 41 is fixedly connected to the ground. The supporting rollers 42 are rotatably connected to the supporting platform 41, and a plurality of supporting rollers 42 are provided. The rotating drive source 43 specifically adopts a motor. The rotating drive source 43 is fixedly connected to the supporting platform 41, and the output shaft of the rotating drive source 43 can drive the supporting rollers 42 to rotate.

[0032] Referring to Figure 2, the flue gas drying kiln 3 includes a basic calcination kiln 31 and a jacket calcination kiln 32. Chambers are provided in both the basic calcination kiln 31 and the jacket calcination kiln 32. The jacket calcination kiln 32 is sleeved outside the basic calcination kiln 31, and the basic calcination kiln 31 and the jacket calcination kiln 32 are coaxial and fixedly connected. A plurality of support roller wheels 42 carry the jacket calcination kiln 32, and a rotation driving source 43 drives the support roller wheels 42 to rotate. The support roller wheels 42 can drive the basic calcination kiln 31 and the jacket calcination kiln 32 to rotate synchronously. The phosphogypsum is located in the basic calcination kiln 31. The basic calcination kiln 31 and the jacket calcination kiln 32 are inclined, and the inclination angle is small. When the basic calcination kiln 31 rotates, it can make the phosphogypsum slowly move from one end to the other end in the basic calcination kiln 31.

[0033] Reference Figure 2 and Figure 3 , both the basic calcination kiln 31 and the jacket calcination kiln 32 are rotatably connected with a first rotating joint 36. The first rotating joint includes a ring body, an outer ring and an inner ring. The outer ring and the inner ring are both fixedly connected to the ring body, and the outer ring is sleeved outside the inner ring. The smoke chamber 2 is communicated with a connecting pipe 5, the connecting pipe 5 is communicated with the inner ring of the first rotating joint 36, and the basic calcination kiln 31 is communicated with the inner ring of the first rotating joint 36. The basic calcination kiln 31 and the jacket calcination kiln 32 are communicated at one end far from the first rotating joint 36. The flue gas in the smoke chamber 2 enters the basic calcination kiln 31 through the connecting pipe 5. The flue gas calcines the phosphogypsum in the basic calcination kiln 31, and then the flue gas enters the jacket calcination kiln 32. In the basic calcination kiln 31, the flue gas and the phosphogypsum move in opposite directions, which can make the contact between the flue gas and the phosphogypsum more sufficient and improve the calcination quality.

[0034] Reference Figure 2 , a guiding wall 33 is formed on the outer wall of the basic calcination kiln 31. The guiding wall 33 is inclined. One end of the jacket calcination kiln 32 far from the first rotating joint 36 is fixedly connected with a guiding ring 39. The outer wall of the guiding ring 39 is inclined. In the direction from one end of the basic calcination kiln 31 close to the first rotating joint 36 to the other end, the guiding wall 33 is in a tapered shape, and the guiding ring 39 is in a flared shape. Dust will be generated when the flue gas calcines the phosphogypsum. The dust in the flue gas settles on the guiding wall 33. The guiding wall 33 guides a part of the dust to the outer wall of the guiding ring 39, and the guiding ring 39 then guides the dust into the basic calcination kiln 31.

[0035] Reference Figure 1 and Figure 2, the outer ring of the first rotary joint 36 is connected to a smoke exhaust pipe 6, and the smoke exhaust pipe 6 is successively connected to a separator 8 and a bag filter 7. The outer ring of the first rotary joint 36 is connected to the jacket calcination kiln 32. The flue gas in the jacket calcination kiln 32 enters the inner part of the outer ring of the first rotary joint 36. Subsequently, the flue gas passes through the smoke exhaust pipe 6 and successively enters the separator 8 and the bag filter 7. The separator 8 has a filter element inside, and the separator 8 can separate gas and dust. The separator 8 can reduce the dust removal load of the bag filter 7. The bag filter 7 removes dust from the flue gas and discharges it up to standard. The smoke exhaust pipe 6 is provided with a bent section. When the flue gas flows through the bent section of the smoke exhaust pipe 6, the flow velocity decreases, and a part of the dust in the flue gas is deposited in the bent section of the smoke exhaust pipe 6. The bent section of the smoke exhaust pipe 6 guides the dust into the first rotary joint 36. The dust in the first rotary joint 36 will enter the guiding wall 33, and finally the guiding wall 33 and the guiding ring 39 cause the dust to enter the basic calcination kiln 31.

[0036] Reference Figure 1 and Figure 2 , the flue gas drying kiln 3 further includes a feeding assembly 34 and a discharging assembly 35. The feeding assembly 34 is located at the higher end of the basic calcination kiln 31 in terms of height, and the discharging assembly 35 is located at the lower end of the basic calcination kiln 31 in terms of height. The feeding assembly 34 includes a feeding bin 341, a feeding conveyor 342, a first switching valve 343, and a feeding pipe 344. The feeding conveyor 342 is specifically a screw conveyor. The feeding bin 341 is connected to the feeding conveyor 342, the feeding conveyor 342 is connected to the feeding pipe 344, the feeding pipe 344 passes through the jacket calcination kiln 32 and is connected to the basic calcination kiln 31, and the first switching valve 343 is connected to the feeding pipe 344. The first switching valve 343 controls the on-off of the feeding pipe 344. Gypsum is put into the feeding bin 341, and the feeding conveyor 342 can input the gypsum into the basic calcination kiln 31. The dust separated by the separator 8 is re-input into the feeding bin 341 for re-calcination treatment.

[0037] Reference Figure 1 and Figure 2, the discharging assembly 35 includes a discharging pipe 351, a second switching valve 352, and a discharging bin 353. The discharging pipe 351 is fixedly connected to the first rotating joint 36. There are two discharging pipes 351, and the two discharging pipes 351 are communicated with each other. The discharging bin 353 is communicated with one of the discharging pipes 351. One discharging pipe 351 is communicated with the inner ring of the first rotating joint 36, and the other discharging pipe 351 is communicated with the outer ring of the first rotating joint 36. The phosphogypsum calcined in the basic calcining kiln 31 enters the discharging pipe 351 through the inner ring of the first rotating joint 36, and the dust at the bottom of the jacket calcining kiln 32 enters the discharging bin 353 through the other discharging pipe 351. The second switching valve 352 is specifically a three-way valve. The second switching valve 352 is fixedly connected to the first rotating joint 36. The second switching valve 352 is respectively connected to the two discharging pipes 351, and the second switching valve 352 can respectively control the on-off of the two discharging pipes 351 and the discharging bin 353.

[0038] The process of calcining phosphogypsum with the waste heat of high-temperature flue gas in the calcining kiln 1 in Embodiment 1 of the present application includes the following steps: The flue gas treated in the smoke chamber 2 passes through the basic calcining kiln 31 and the jacket calcining kiln 32 and then enters the bag filter 7 from the exhaust pipe 6. The rotation driving source 43 drives the support roller 42 to rotate, so that the basic calcining kiln 31 and the jacket calcining kiln 32 rotate, driving the phosphogypsum to move in the basic calcining kiln 31, and the flue gas and the phosphogypsum move in opposite directions in the basic calcining kiln 31; the bag filter 7 performs dust removal treatment on the flue gas and discharges it up to standard.

[0039] The implementation principle of a system and process for calcining phosphogypsum with the waste heat of high-temperature flue gas in the calcining kiln 1 in Embodiment 1 of the present application is as follows: The flue gas in the calcining kiln 1 enters the smoke chamber 2 for dust removal, and then the flue gas passes through the basic calcining kiln 31 and the jacket calcining kiln 32 in sequence. The flue gas calcines the phosphogypsum, and the dust generated by calcining the phosphogypsum settles on the bent section of the exhaust pipe 6 and the guiding wall 33. The guiding wall 33 and the guiding ring 39 guide the dust into the basic calcining kiln 31, thereby reducing the dust content in the flue gas and reducing the dust removal load of the bag filter 7. The basic calcining kiln 31 and the jacket calcining kiln 32 can perform secondary cooling on the flue gas, improving the utilization efficiency of the waste heat of the flue gas.

[0040] Embodiment 2: Embodiment 2 of the present application provides a system for calcining phosphogypsum with the waste heat of high-temperature flue gas in a calcining kiln. The difference between Embodiment 2 and Embodiment 1 of the present application is as follows: Refer to Figure 4, the discharging assembly 35 further includes a discharging conveyor 354, which is specifically a screw conveyor. The discharging conveyor 354 is respectively connected to the discharging bin 353 and the feeding mechanism 12. The calcined phosphogypsum collected in the discharging bin 353 is input into the feeding mechanism 12 through the discharging conveyor 354, and then the feeding mechanism 12 inputs the calcined phosphogypsum into the calcining kiln 1, so that phosphogypsum ceramsite can be calcined in the calcining kiln 1.

[0041] Embodiment 3: Embodiment 3 of the present application provides a phosphogypsum calcining system using the waste heat of high-temperature flue gas in a calcining kiln. The difference between Embodiment 3 of the present application and Embodiment 2 is that: Reference Figure 5 , the phosphogypsum conveying assembly 4 further includes a spiral blade 44. The spiral blade 44 is fixedly connected inside the basic calcining kiln 31, so that the flue gas advances spirally along the spiral blade 44, which can reduce the flow velocity of the flue gas. And when the basic calcining kiln 31 rotates, it can drive the spiral blade 44 to rotate together, and the spiral blade 44 drives the phosphogypsum to move from one end to the other end inside the basic calcining kiln 31. The flue gas and the phosphogypsum meet inside the spiral blade 44, which can make the contact between the flue gas and the phosphogypsum more sufficient.

[0042] Embodiment 4: Embodiment 4 of the present application provides a phosphogypsum calcining system using the waste heat of high-temperature flue gas in a calcining kiln. The difference between Embodiment 4 of the present application and Embodiment 3 is that: Reference Figure 6 and Figure 7 , both ends of the basic calcining kiln 31 and the jacket calcining kiln 32 are respectively rotatably connected with a second rotating joint 37 and a third rotating joint 38. The second rotating joint 37 has the same structure as the first rotating joint 36, that is, the second rotating joint 37 also has an inner ring and an outer ring. The connecting pipe 5 is communicated with the outer ring of the second rotating joint 37. The outer ring of the second rotating joint 37 is communicated with the jacket calcining kiln 32. The jacket calcining kiln 32 is communicated with the third rotating joint 38. The third rotating joint 38 is communicated with the basic calcining kiln 31. The basic calcining kiln 31 is communicated with the inner ring of the second rotating joint 37. The inner ring of the second rotating joint 37 is communicated with the exhaust pipe 6. The flue gas in the smoke chamber 2 enters the second rotating joint 37 through the connecting pipe 5, and then the flue gas sequentially passes through the jacket calcining kiln 32, the third rotating joint 38, the basic calcining kiln 31 and the exhaust pipe 6 and enters the bag filter 7. The bent section of the exhaust pipe 6 can introduce the dust in the flue gas into the inner ring of the second rotating joint 37, so that the dust enters the basic calcining kiln 31.

[0043] Reference Figure 6 and Figure 7, in this embodiment, the height of the base calcination kiln 31 near one end of the second rotary joint 37 is higher than that of the other end, and the phosphogypsum moves in the base calcination kiln 31 from the end near the second rotary joint 37 towards the end near the third rotary joint 38.

[0044] Reference Figure 6 and Figure 7 , the feeding assembly 34 includes a feeding bin 341, a feeding pipe 344 and a first switching valve 343. The feeding pipe 344 passes through the second rotary joint 37 and communicates with the base calcination kiln 31. The feeding bin 341 communicates with the feeding pipe 344. The first switching valve 343 is connected to the feeding pipe 344, and the first switching valve 343 controls the on-off of the feeding pipe 344. The discharge pipe 351 communicates with the third rotary joint 38. The second switching valve 352 is connected to the discharge pipe 351, and the second switching valve 352 controls the on-off of the discharge pipe 351. Phosphogypsum is put into the feeding bin 341, and the phosphogypsum enters the base calcination kiln 31. After being calcined, the phosphogypsum enters the third rotary joint 38 from the base calcination kiln 31, and then the phosphogypsum enters the discharge bin 353 from the discharge pipe 351.

[0045] The above are all the preferred embodiments of the present application. The protection scope of the present application is not limited by this. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln, characterized in that: The invention comprises a calcining device, a smoke chamber (2), a smoke chamber (2) waste heat calcining device and a flue gas purification device; the calcining device comprises a calcining kiln (1), and the calcining kiln (1) is used to calcine ceramsite; the smoke chamber (2) waste heat calcining device comprises a flue gas drying kiln (3), and the flue gas purification device comprises a bag filter (7); the smoke chamber (2) is connected to the calcining kiln (1), and the smoke chamber (2) performs dust reduction treatment on the flue gas generated by the calcining kiln (1); The flue gas drying kiln (3) comprises a basic calcining kiln (31) and a jacketed calcining kiln (32), wherein the jacketed calcining kiln (32) is sleeved on the outside of the basic calcining kiln (31), and the jacketed calcining kiln (32) is connected to the basic calcining kiln (31), and the basic calcining kiln (31) is used to calcine phosphogypsum; the basic calcining kiln (31) and the jacketed calcining kiln (32) are both provided with chambers, and the basic calcining kiln (31) and the jacketed calcining kiln (32) are connected at one end, one of the chambers is connected to the smoke chamber (2), and the other chamber is connected to the bag filter (7), and the smoke from the smoke chamber (2) passes through the two chambers in sequence and then enters the bag filter (7), and the bag filter (7) performs dust reduction treatment on the smoke passing through.

2. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 1, characterized in that: It also includes a phosphogypsum conveying component (4), which drives the phosphogypsum to move in the basic calcining kiln (31), so that the phosphogypsum and the flue gas move towards each other in the basic calcining kiln (31).

3. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 2, characterized in that: The smoke chamber (2) is in communication with the basic calcining kiln (31), and the jacketed calcining kiln (32) is in communication with the bag filter (7).

4. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 3, characterized in that: The outer wall of the basic calcining kiln (31) is provided with a guide wall (33), the guide wall (33) is arranged obliquely, and dust from the flue gas in the jacket calcining kiln (32) is deposited on the guide wall (33); the end of the jacket calcining kiln (32) is connected to a guide ring (39), the outer wall of the guide ring (39) is arranged obliquely, the guide wall (33) guides dust to the guide ring (39), and the guide ring (39) guides dust into the basic calcining kiln (31).

5. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 4, characterized in that: The ends of the jacketed calcining kiln (32) and the basic calcining kiln (31) are rotatably connected to a first rotating joint (36), and the first rotating joint (36) is provided with an inner ring and an outer ring; the basic calcining kiln (31) is connected to the inner ring of the first rotating joint (36), and a connecting pipe (5) is connected between the inner ring of the first rotating joint (36) and the smoke chamber (2); the jacketed calcining kiln (32) is connected to the outer ring of the first rotating joint (36), and a smoke exhaust pipe (6) is connected between the outer ring of the first rotating joint (36) and the bag dust collector (7); the smoke exhaust pipe (6) is provided with a curved section, and dust in the smoke is deposited on the curved section of the smoke exhaust pipe (6), and the curved section of the smoke exhaust pipe (6) guides the dust into the jacketed calcining kiln (32).

6. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 2, characterized in that: The smoke chamber (2) is in communication with the jacketed calcining kiln (32), and the basic calcining kiln (31) is in communication with the bag filter (7).

7. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 6, characterized in that: The two ends of the jacketed calcining kiln (32) are rotatably connected to a second rotating joint (37) and a third rotating joint (38), respectively; the second rotating joint (37) is provided with an outer ring and an inner ring; the jacketed calcining kiln (32) is in communication with the outer ring of the second rotating joint (37); a connecting pipe (5) is in communication between the smoke chamber (2) and the outer ring of the second rotating joint (37); the jacketed calcining kiln (32) is in communication with the basic calcining kiln (31) via the third rotating joint (38); the basic calcining kiln (31) is in communication with the inner ring of the second rotating joint (37); a smoke exhaust pipe (6) is in communication between the bag filter (7) and the inner ring of the second rotating joint (37); the smoke exhaust pipe (6) is provided with a curved section; dust in the smoke is deposited on the curved section of the smoke exhaust pipe (6); the curved section of the smoke exhaust pipe (6) guides the dust into the basic calcining kiln (31).

8. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 2, characterized in that: The phosphogypsum conveying assembly (4) comprises a support platform (41), a support roller (42) and a rotation driving source (43); the support roller (42) is rotationally connected to the support platform (41), a plurality of the support rollers (42) are provided, the plurality of support rollers (42) support the jacket calcining kiln (32), and the basic calcining kiln (31) is tilted; the rotation driving source (43) drives the support roller (42) to rotate, so that the jacket calcining kiln (32) and the basic calcining kiln (31) rotate.

9. A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln according to claim 8, characterized in that: The basic calcining kiln (31) is connected to a spiral blade (44), and the flue gas inside the basic calcining kiln (31) flows along the spiral blade (44).

10. A process for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln, characterized in that: A system for calcining phosphogypsum using waste heat from high-temperature flue gas from a calcining kiln as claimed in any one of claims 1 to 9 comprises the following steps: the flue gas treated in the smoke chamber (2) passes through two chambers in sequence and then enters a bag filter (7); a rotating driving source (43) drives the supporting roller (42) to rotate, so that the basic calcining kiln (31) and the jacket calcining kiln (32) rotate, driving the phosphogypsum to move in the basic calcining kiln (31), and the flue gas and the phosphogypsum move towards each other in the basic calcining kiln (31); the bag filter (7) performs dust reduction treatment on the flue gas and discharges it in compliance with the emission standards.

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