Integrated equipment for carrying out calcination modification and sorting on phosphogypsum by utilizing product waste heat

Abstract

The invention relates to the technical field of ardealite processing, and provides integrated equipment for carrying out calcination modification and sorting on ardealite by utilizing product waste heat, which comprises a rotary kiln system, a sorting dust removal system and a negative pressure fan, the phosphogypsum is heated by the rotary kiln system; the sorting and dust removing system comprises a sorting device and a cyclone dust remover, the sorting device comprises a sorting chamber and a screening structure, the sorting chamber is provided with a gas outlet, a material recycling opening, a first sorting opening and a second sorting opening, the discharging end of the rotary kiln system is connected with the screening structure, and the first sorting opening collects screened materials of the screening structure; the first sorting opening is used for receiving materials recycled from the material recycling opening, the second sorting opening is used for collecting oversize materials of the screening structure, an air inlet of the cyclone dust collector is communicated with the air outlet, and a discharging opening of the cyclone dust collector is communicated with the material recycling opening through an air locking discharging valve; and the negative pressure fan is communicated with an air outlet of the cyclone dust collector so as to carry out air extraction treatment on the cyclone dust collector. The problems of finished product screening and dust removal treatment in gypsum production are well solved.

Description

Technical Field

[0001] This invention relates to the field of phosphogypsum processing technology, and in particular to an integrated device for calcining, modifying and sorting phosphogypsum using waste heat from the product. Background Technology

[0002] In gypsum production, phosphogypsum undergoes drying, dehydration, and modification processes sequentially to obtain modified gypsum with low water of crystallization content (such as hemihydrate or anhydrous gypsum). This process typically involves heating the phosphogypsum with high-temperature expanded clay aggregates. However, upon contact between the expanded clay aggregates and the phosphogypsum, the thermal decomposition of the phosphogypsum generates a large amount of water vapor and dust. The water vapor triggers a hydration reaction in the calcined and modified phosphogypsum, causing it to solidify and harden. The dust is usually mixed with the modified, suspended gypsum powder, all of which severely affect the subsequent sorting of the finished product (modified phosphogypsum), making dust removal quite difficult.

[0003] However, in practical applications, it has been found that existing gypsum processing equipment has a simple structure and limited functions, making it difficult to effectively solve the problems of finished product screening and dust removal in gypsum production. Summary of the Invention

[0004] This invention provides an integrated device for calcining, modifying, and sorting phosphogypsum using waste heat from the product, which at least solves or improves the problem that existing gypsum processing methods struggle to effectively address finished product screening and dust removal in gypsum production.

[0005] This invention provides an integrated device for calcining, modifying, and sorting phosphogypsum using waste heat from a product, comprising: A rotary kiln system for mixing high-temperature ceramsite with phosphogypsum to heat the phosphogypsum; The sorting and dust removal system includes a sorting device and a cyclone dust collector. The sorting device includes a sorting chamber and a screening structure disposed within the sorting chamber. The sorting chamber has a gas outlet, a material recovery port, a first sorting port, and a second sorting port. The discharge end of the rotary kiln system extends into the sorting chamber and is connected to the screening structure. The first sorting port is used to collect the undersize material from the screening structure and to receive the material recovered from the material recovery port. The second sorting port is used to collect the oversize material from the screening structure. The air inlet of the cyclone dust collector is connected to the gas outlet, and the discharge port of the cyclone dust collector is connected to the material recovery port through an airlock discharge valve. A negative pressure fan is connected to the air outlet of the cyclone dust collector to extract air from the cyclone dust collector.

[0006] According to the present invention, an integrated device for calcining, modifying and sorting phosphogypsum using product waste heat is provided. The screening structure is a cylindrical screen, the first end of which is connected to the discharge end of the rotary kiln system, and the cylindrical screen is rotated by the discharge end of the rotary kiln system. The first sorting port is located on the lower side of the cylindrical screen, and the second sorting port is located opposite to the second end of the cylindrical screen.

[0007] According to the present invention, an integrated device for calcining, modifying and sorting phosphogypsum using waste heat of a product is provided. The sorting device and the cyclone dust collector are integrated into one structure and are housed inside an insulated protective cover.

[0008] According to the present invention, an integrated device for calcining, modifying, and sorting phosphogypsum using waste heat from a product is provided, wherein the rotary kiln system comprises: The first rotary kiln is used to heat the ceramsite to obtain high-temperature ceramsite. The mixing chamber includes a housing, a guide channel, and a feed channel. The guide channel is inclinedly disposed within the housing. The tail of the first rotary kiln extends into the housing and communicates with the upper end of the guide channel. The first end of the feed channel is located outside the housing, and the second end of the feed channel is disposed within the housing and communicates with the middle of the guide channel. The first end of the feed channel is used to input the phosphogypsum. The second rotary kiln has its kiln head extending into the box body and communicating with the lower end of the material guide channel. The kiln tail of the second rotary kiln serves as the discharge end of the rotary kiln system.

[0009] According to the present invention, an integrated device for calcining, modifying and sorting phosphogypsum using waste heat of products is provided. A fuel input pipe is inserted into the kiln tail of the first rotary kiln. The fuel input pipe is configured to feed biomass fuel into the kiln tail of the first rotary kiln under the drive of compressed air, so as to calcine the ceramsite in the first rotary kiln based on the combustion of the biomass fuel. The second rotary kiln is equipped with a vent pipe at its kiln head. The vent pipe is used to introduce air into the second rotary kiln to aid combustion of hydrogen formed by the water-gas reaction and organic matter obtained by the thermal decomposition of phosphogypsum.

[0010] According to the present invention, an integrated device for calcining, modifying and sorting phosphogypsum using waste heat of a product is provided, wherein the material guiding channel is provided with a check valve structure. The anti-reverse structure includes multiple baffles, all of which are disposed on the top wall of the material guide channel and arranged sequentially along the material conveying direction of the material guide channel; the baffles extend downward at an angle toward the bottom wall of the material guide channel, and the extension direction of the baffles forms an acute angle with the material conveying direction of the material guide channel.

[0011] According to the present invention, an integrated device for calcining, modifying and sorting phosphogypsum using waste heat of the product is provided, wherein a distribution stacker is provided at the kiln tail of the first rotary kiln, and the distribution stacker is used to transport the high-temperature ceramsite in the first rotary kiln to the material guide channel. The distributed material stacker includes multiple spiral guide plates, which are arranged sequentially along the circumference of the tail of the first rotary kiln, and a discharge channel is formed between two adjacent spiral guide plates.

[0012] According to the present invention, an integrated device for calcining, modifying and sorting phosphogypsum using waste heat of the product is provided, wherein the second rotary kiln is provided with a spiral conveyor and multiple lifting plates. The spiral conveyor plate is disposed on the inner wall of the second rotary kiln and extends along a spiral trajectory relative to the central axis of the second rotary kiln; a plurality of the lifting plates are disposed on the inner wall of the second rotary kiln and located near the kiln head of the second rotary kiln, and each of the lifting plates extends along the axial direction of the second rotary kiln. The radial height of the lifting plate relative to the inner wall of the second rotary kiln is lower than the radial height of the spiral conveyor plate relative to the inner wall of the second rotary kiln.

[0013] According to the present invention, an integrated device for calcining, modifying, and sorting phosphogypsum using waste heat from a product is provided, wherein the rotary kiln system further includes: A smoke exhaust chamber includes a chamber body and a dust removal structure disposed within the chamber body, the dust removal structure being used for dust removal treatment of flue gas; The flue gas chamber body has a flue gas inlet, an ash discharge port, and a flue gas outlet. The flue gas inlet is connected to the kiln head of the first rotary kiln. The ash discharge port is used to discharge the dust intercepted in the flue gas dust removal process by the dust removal structure. The flue gas outlet is used to discharge the gas after dust removal by the dust removal structure.

[0014] The integrated equipment for calcining, modifying and sorting phosphogypsum using waste heat from the product, provided by the present invention, further includes: a water scrubbing tower and a multi-stage sedimentation tank. The negative pressure fan and the air inlet of the water shower tower are connected. The water shower tower is used to wash the gas discharged by the negative pressure fan. The liquid outlet of the water shower tower is connected to multiple sedimentation tanks. The sedimentation tanks are used to precipitate gypsum in the liquid discharged from the liquid outlet.

[0015] This invention provides an integrated device for calcining, modifying, and sorting phosphogypsum using waste heat from the product. By employing a rotary kiln system to mix high-temperature ceramsite with phosphogypsum, the rotary kiln system's rotational conveying allows for full utilization of the waste heat from the ceramsite to calcine the phosphogypsum. Simultaneously, it ensures the phosphogypsum remains in a dynamic conveying state within the rotary kiln system, preventing water vapor during calcination from triggering a hydration reaction in the modified phosphogypsum, thus preventing it from solidifying and hardening. The sorting and dust removal system incorporates a sorting device and a cyclone dust collector, with a negative pressure fan installed at the outlet of the cyclone dust collector. Powered by the negative pressure fan, water vapor and dust are ensured to enter the sorting device along with the material output from the rotary kiln system. The screening structure of the sorting device then separates these materials (including...). The modified phosphogypsum and the high-temperature ceramsite after heat exchange are sorted together. The undersize material (modified phosphogypsum) is collected at the first sorting port, and the oversize material (high-temperature ceramsite after heat exchange) is collected at the second sorting port. Water vapor and suspended solids (including gypsum powder and dust) in the sorting chamber enter the cyclone dust collector from the gas outlet. After being treated by the cyclone dust collector, the relatively heavy gypsum powder is returned to the sorting chamber under the control of the airlock discharge valve and collected at the first sorting port. The relatively light dust is discharged through the outlet of the cyclone dust collector. This design structure can efficiently achieve the sorting and recycling of calcined ceramsite and modified phosphogypsum, and achieve the separation of dust and modified phosphogypsum, resulting in better finished product screening and dust removal effects. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is one of the structural schematic diagrams of the integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat provided by the present invention.

[0018] Figure 2 This is the second schematic diagram of the integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat provided by the present invention.

[0019] Figure 3 This is a three-dimensional structural diagram of the sorting and dust removal system provided by the present invention.

[0020] Figure 4 This is a cross-sectional structural diagram of the sorting and dust removal system provided by the present invention.

[0021] Figure 5 This is a three-dimensional structural schematic diagram of the rotary kiln system provided by the present invention.

[0022] Figure 6 This is a cross-sectional structural schematic diagram of the rotary kiln system provided by the present invention.

[0023] Figure 7 This is a three-dimensional structural diagram of the smoke exhaust chamber provided by the present invention.

[0024] Figure 8 This is a cross-sectional structural schematic diagram of the smoke exhaust chamber provided by the present invention.

[0025] Figure label: 1. Rotary kiln system; 11. First rotary kiln; 111. Fuel input pipe; 112. Distributor stacker; 12. Mixing chamber; 121. Housing; 122. Material guide channel; 1221. Backstop structure; 123. Feed channel; 13. Second rotary kiln; 131. Spiral conveyor plate; 132. Lifting plate; 14. Exhaust chamber; 141. Exhaust chamber body; 142. Dust removal structure; 1401. Flue gas inlet; 1402. Ash discharge port; 1403. Flue gas outlet; 2. Sorting and dust removal system; 21. Sorting device; 211. Sorting chamber; 2111. Gas outlet; 2112. Material recovery port; 2113. First sorting port; 2114. Second sorting port; 212. Screening structure; 22. Cyclone dust collector; 2201. Airlock discharge valve; 221. Air inlet; 222. Discharge port; 223. Air outlet; 3. Negative pressure fan; 4. Water shower tower; 5. Sedimentation tank. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The following is combined with Figures 1 to 8 The integrated equipment for calcining, modifying and sorting phosphogypsum using waste heat from products, provided by the present invention, is described in detail through specific embodiments and application scenarios.

[0028] like Figure 1 , Figure 3 and Figure 4 As shown, this embodiment of the invention provides an integrated device for calcining, modifying and sorting phosphogypsum using waste heat from the product, including: a rotary kiln system 1, a sorting and dust removal system 2 and a negative pressure fan 3; Rotary kiln system 1 is used to mix high-temperature ceramsite with phosphogypsum to heat the phosphogypsum; the sorting and dust removal system 2 includes a sorting device 21 and a cyclone dust collector 22. The sorting device 21 includes a sorting chamber 211 and a screening structure 212 disposed within the sorting chamber 211. The sorting chamber 211 has a gas outlet 2111, a material recovery port 2112, a first sorting port 2113, and a second sorting port 2114. The discharge end of the rotary kiln system 1 extends into the sorting chamber 211 and is connected to the screening structure 212. The sorting port 2113 is used to collect the undersize material from the screening structure 212 and to receive the material recovered from the material recovery port 2112. The second sorting port 2114 is used to collect the oversize material from the screening structure 212. The air inlet 221 and the gas outlet 2111 of the cyclone dust collector 22 are connected. The discharge port 222 of the cyclone dust collector 22 is connected to the material recovery port 2112 through the airlock discharge valve 2201. The negative pressure fan 3 is connected to the air outlet 223 of the cyclone dust collector 22 to perform air extraction treatment on the cyclone dust collector 22.

[0029] It is understandable that by using rotary kiln system 1 to mix high-temperature ceramsite with phosphogypsum, the rotary conveying of rotary kiln system 1 can be utilized to fully utilize the residual heat of high-temperature ceramsite to calcine phosphogypsum, while ensuring that phosphogypsum is always in a dynamic conveying state in rotary kiln system 1. This prevents water vapor during the calcination process from causing the calcined and modified phosphogypsum to undergo a hydration reaction, thereby causing it to solidify and harden.

[0030] The calcination modification of phosphogypsum typically refers to converting low-activity dihydrate gypsum into high-activity hemihydrate or anhydrous gypsum. The temperature of the high-temperature ceramsite is not lower than 100℃, for example, not lower than 800℃. Optionally, the temperature of the high-temperature ceramsite is 800-1100℃.

[0031] Considering that during the heating process of phosphogypsum using high-temperature ceramsite, besides a small portion of the moisture generated by the thermal decomposition of phosphogypsum being adsorbed by the high-temperature ceramsite upon contact with the phosphogypsum, a large portion of the moisture exists in the rotary kiln system 1 as water vapor. In this case, by setting a sorting device 21 and a cyclone dust collector 22 in the sorting and dust removal system 2, and installing a negative pressure fan 3 at the outlet 223 of the cyclone dust collector 22, the power provided by the negative pressure fan 3 ensures that water vapor and dust enter the sorting device 21 along with the material output from the rotary kiln system 1. The screening structure 212 of the sorting device 21 then separates these materials (including modified phosphogypsum). The process involves sorting the phosphogypsum (after heat exchange) into the first sorting port 2113, while the oversize phosphogypsum (after heat exchange) is collected at the second sorting port 2114. Water vapor and suspended solids (including gypsum powder and dust) in the sorting chamber 211 enter the cyclone dust collector 22 through the gas outlet 2111. After cyclone dust removal by the cyclone dust collector 22, the relatively heavy gypsum powder returns to the sorting chamber 211 under the control of the airlock discharge valve 2201 and is collected at the first sorting port 2113. The relatively light dust is discharged through the outlet 223 of the cyclone dust collector 22 for subsequent dust removal.

[0032] It should be noted that the airlock discharge valve 2201 is a rotary airlock valve or planetary unloader known in the art. By setting the airlock discharge valve 2201, it can be ensured that the gypsum powder (modified phosphogypsum) collected by the cyclone dust collector 22 is smoothly discharged into the sorting chamber 211, and there is no gas communication between the cyclone dust collector 22 and the sorting chamber 211 through the airlock discharge valve 2201, so as to realize the recovery of gypsum powder.

[0033] Meanwhile, by connecting the negative pressure fan 3 and the air outlet 223 of the cyclone dust collector 22, the negative pressure fan 3 is positioned in a rear-mounted layout relative to the entire sorting and dust removal system 2. This design allows the heat in the entire rotary kiln system 1 to reach the cyclone dust collector 22 with the airflow, ensuring the continuous operation of each unit of the system. It also prevents condensation from occurring in the sorting chamber 211 due to localized low temperatures, and prevents hydration reactions between the condensate and the modified phosphogypsum, which could lead to blockages and shutdowns.

[0034] As can be seen from the above, the integrated equipment for calcining, modifying and sorting phosphogypsum using waste heat of the product described in this invention can fully heat the phosphogypsum using the rotary kiln system 1 to prevent the calcined and modified phosphogypsum from agglomerating. Then, based on the sorting device 21 and the cyclone dust collector 22, the calcined ceramsite and modified phosphogypsum can be sorted and recycled better, and the dust and modified phosphogypsum can be separated to achieve better finished product screening and dust removal effects.

[0035] In some embodiments, such as Figure 4 As shown, the screening structure 212 is a cylindrical screen. The first end of the cylindrical screen is connected to the discharge end of the rotary kiln system 1, and the cylindrical screen is driven to rotate by the discharge end of the rotary kiln system 1. The first sorting port 2113 is set on the lower side of the cylindrical screen, and the second sorting port 2114 is set opposite to the second end of the cylindrical screen.

[0036] Understandably, by setting the rotary kiln system 1 to drive the cylindrical screen to rotate, there is no need to set up additional power equipment for the cylindrical screen. Instead, the rotary power of the rotary kiln system 1 is fully utilized. This design reduces the space occupied by the entire sorting chamber 211. While achieving efficient screening without power input, it also achieves a good energy-saving and carbon-reducing effect.

[0037] In practical applications, the central axis of the cylindrical screen is roughly horizontal. For example, the inclination angle of the central axis of the cylindrical screen relative to the horizontal plane is controlled within ±10°. The undersize material (modified phosphogypsum) after being screened by the cylindrical screen falls to the first sorting port 2113 under its own weight. A screw conveyor can be installed on the inner side of the cylindrical screen to ensure that the oversize material in the cylindrical screen reaches the second end of the cylindrical screen via the screw conveyor, and then falls to the second sorting port 2114 under its own weight.

[0038] Meanwhile, the cylindrical screen can be set with multiple screening layers. In this case, multiple second sorting ports 2114 can be set, and the multiple second sorting ports 2114 are respectively set opposite to the corresponding discharge ends of the multiple screening layers.

[0039] In some embodiments, such as Figure 3 and Figure 4 As shown, the sorting device 21 and the cyclone dust collector 22 are an integrated structure and are housed inside an insulated protective cover.

[0040] Understandably, in order to facilitate both finished product sorting and cyclone dust removal, the cyclone dust collector 22 is located on the upper side of the sorting device 21.

[0041] At the same time, by integrating the sorting device 21 and the cyclone dust collector 22 into a single structure, the entire sorting and dust removal system 2 can be designed to be compact and miniaturized, so that it can be built into the heat-insulating protective cover. Based on the heat-insulating protective cover, the system can be prevented from condensing due to local low temperature, and from reacting with the modified phosphogypsum under the action of condensation, which could lead to blockage and shutdown.

[0042] In some embodiments, such as Figure 1 and Figure 2As shown, the rotary kiln system 1 includes: a first rotary kiln 11, a mixing chamber 12, and a second rotary kiln 13; the first rotary kiln 11 is used to heat the ceramsite to obtain high-temperature ceramsite; the mixing chamber 12 includes a box body 121, a guide channel 122, and a feed channel 123; the guide channel 122 is inclinedly arranged inside the box body 121, the kiln tail of the first rotary kiln 11 extends into the box body 121 and is connected to the upper end of the guide channel 122, the first end of the feed channel 123 is located outside the box body 121, the second end of the feed channel 123 is located inside the box body 121 and is connected to the middle of the guide channel 122, and the first end of the feed channel 123 is used to input phosphogypsum; the kiln head of the second rotary kiln 13 extends into the box body 121 and is connected to the lower end of the guide channel 122, and the kiln tail of the second rotary kiln 13 serves as the discharge end of the rotary kiln system 1.

[0043] It is understandable that, such as Figure 2 As shown, the first rotary kiln 11 rotates around the first rotary axis K1 under the drive of the first rotary structure, and the second rotary kiln 13 rotates around the second rotary axis K2 under the drive of the second rotary structure; the inclination angle of the first rotary axis K1 relative to the horizontal plane is β, and the inclination angle of the second rotary axis K1 relative to the horizontal plane is α; wherein, both the first rotary axis K1 and the second rotary axis K2 can be configured to be inclined upward relative to the horizontal plane.

[0044] In practical applications, the kiln head of the first rotary kiln 11 is used to input the ceramsite to be heated, and the kiln tail of the first rotary kiln 11 is used to input biomass fuel. The ceramsite is heated based on the combustion of biomass fuel. The high-temperature flue gas generated during the combustion of biomass fuel can be used to heat the ceramsite. For example, the conveying direction of the ceramsite in the first rotary kiln 11 is set to be opposite to the conveying direction of the high-temperature flue gas in the first rotary kiln 11, thereby realizing the full utilization of the thermal energy of biomass fuel combustion.

[0045] In some embodiments, by controlling the amount of phosphogypsum to be calcined and the rotation speed of the second rotary kiln 13 during the mixing and calcination process (to control the calcination time of the phosphogypsum), different calcined products can be output by the second rotary kiln 13. For example, the calcined product output by the second rotary kiln 13 can be either hemihydrate gypsum or anhydrous gypsum.

[0046] For example, such as Figure 5 and Figure 6 As shown, a fuel input pipe 111 is inserted at the kiln tail of the first rotary kiln 11. The fuel input pipe 111 is configured to feed biomass fuel into the kiln tail of the first rotary kiln 11 under the drive of compressed air, so as to calcine the ceramsite in the first rotary kiln 11 based on the combustion of biomass fuel.

[0047] In practical applications, since the tail of the first rotary kiln 11 extends into the housing 121, the fuel input pipe 111 can be inserted into the kiln tail of the first rotary kiln 11 through the mixing chamber 12, thereby feeding biomass fuel into a section of the kiln body near the kiln tail of the first rotary kiln 11. During the process of conveying biomass fuel using the fuel input pipe 111, compressed air serves as the power source for conveying biomass fuel into the first rotary kiln 11, ensuring the oxygen supply during biomass fuel combustion. The biomass fuel can be straw, sawdust, rice husks, wheat bran, etc., without specific limitations.

[0048] Meanwhile, by setting up a mixing chamber 12 between the first rotary kiln 11 and the second rotary kiln 13, the material guide channel 122 and the feed channel 123 can be arranged based on the mixing chamber 12. While achieving a better connection between the kiln tail of the first rotary kiln 11 and the kiln head of the second rotary kiln 13, it is also possible to mix the high-temperature ceramsite with the fed phosphogypsum based on the feeding through the feed channel 123. This prevents the generation of large amounts of dust at the moment of mixing of the high-temperature ceramsite and phosphogypsum, and also prevents heat loss between the two rotary kilns.

[0049] For example, such as Figure 5 and Figure 6 As shown, a vent pipe is inserted into the kiln head of the second rotary kiln 13. The vent pipe is used to introduce air into the second rotary kiln 13 to assist in the combustion of hydrogen formed by the water-gas reaction and organic matter obtained by the thermal decomposition of phosphogypsum in the second rotary kiln 13.

[0050] Understandably, when high-temperature expanded clay and phosphogypsum are mixed, the water of crystallization in the phosphogypsum will instantly vaporize into water vapor, causing calcium sulfate dihydrate to convert into anhydrous calcium sulfate or calcium sulfate hemihydrate. The phosphogypsum will also yield organic matter through thermal decomposition, such as gases like CO, CH4, and C2H4, along with carbonaceous residues (semi-coke, carbon black). Under the high-temperature environment provided by the expanded clay (above 800℃), the water vapor (H2O) will react with the carbon in the second rotary kiln 13 to produce water gas, forming hydrogen. At least some of this carbon comes from the incomplete combustion of biomass fuel.

[0051] In this scenario, air is introduced into the second rotary kiln 13 through the vent pipe. The oxygen in the air assists the combustion of hydrogen formed by the water-gas reaction in the second rotary kiln 13 and the organic matter obtained from the thermal decomposition of phosphogypsum, achieving an instantaneous burst of hydrogen energy. This, combined with the utilization of the heat energy from the combustion of organic matter, allows for more thorough improvement of the phosphogypsum within the second rotary kiln 13. Furthermore, the positive pressure created by the air, in conjunction with the rear-mounted negative pressure fan 3, drives the heat in the second rotary kiln 13, along with the water vapor and dust generated during the heating of the phosphogypsum, towards the sorting and dust removal system 2. This reduces waste heat loss, ensures full utilization of heat, and further reduces the hydration reaction that may occur during the transport of the improved phosphogypsum, ensuring the continuity of production for the entire system.

[0052] In some embodiments, such as Figure 6 As shown, a backstop structure 1221 is provided in the material guide channel 122; the backstop structure 1221 includes multiple baffles, which are all disposed on the top wall of the material guide channel 122 and arranged sequentially along the material conveying direction of the material guide channel 122; the baffles extend downward toward the bottom wall of the material guide channel 122 at an acute angle to the material conveying direction of the material guide channel 122.

[0053] It is understandable that, since the second end of the feed channel 123 is located inside the housing 121 and is connected to the middle of the guide channel 122, by tilting each baffle toward the side of the material conveying direction in the guide channel 122, this design will not affect the normal conveying of the high-temperature ceramsite in the first rotary kiln 11 to the second rotary kiln 13 along the guide channel 122. It can solve the problem of vaporization escape that occurs when the high-temperature ceramsite comes into contact with phosphogypsum, that is, it can prevent the dust and water vapor generated by the thermal decomposition of phosphogypsum from flowing backward into the guide channel 122 and reaching the kiln tail of the first rotary kiln 11, thus affecting the normal production operation of the first rotary kiln 11.

[0054] In practical applications, the kiln tail of the first rotary kiln 11 can be set at a height higher than the kiln head of the second rotary kiln 13. The material guide channel 122 is set at an angle downwards, and the opening size of the material guide channel 122 toward the kiln tail of the first rotary kiln 11 is larger than the opening size of the material guide channel 122 toward the kiln head of the second rotary kiln 13.

[0055] In some embodiments, such as Figure 6 As shown, a distribution stacker 112 is provided at the kiln tail of the first rotary kiln 11. The distribution stacker 112 is used to transport the high-temperature ceramsite in the first rotary kiln 11 to the material guide channel 122. The distribution stacker 112 includes multiple spiral guide plates, which are arranged sequentially along the circumference of the kiln tail of the first rotary kiln 11, and a discharge channel is formed between two adjacent spiral guide plates.

[0056] Understandably, during the rotation of the first rotary kiln 11, the first rotary kiln 11 drives the distribution stacker 112 to rotate synchronously. The distribution stacker 112 discharges the material (high-temperature ceramsite) located at the kiln tail of the first rotary kiln 11 in sequence based on each discharge channel, which can effectively ensure that the high-temperature ceramsite will not be blocked at the kiln tail of the first rotary kiln 11.

[0057] In some embodiments, such as Figure 6 As shown, the second rotary kiln 13 is provided with a spiral conveyor plate 131 and a plurality of lifting plates 132; the spiral conveyor plate 131 is disposed on the inner wall of the second rotary kiln 13 and extends along a spiral trajectory relative to the central axis of the second rotary kiln 13; the plurality of lifting plates 132 are disposed on the inner wall of the second rotary kiln 13 and are located near the kiln head of the second rotary kiln 13, and each lifting plate 132 extends along the axial direction of the second rotary kiln 13; wherein, the radial height of the lifting plate 132 relative to the inner wall of the second rotary kiln 13 is lower than the radial height of the spiral conveyor plate 131 relative to the inner wall of the second rotary kiln 13.

[0058] It is understandable that by setting a spiral conveyor plate 131 and multiple lifting plates 132 in the second rotary kiln 13, and setting the lifting plates 132 near the kiln head of the second rotary kiln 13, the material (including phosphogypsum and high-temperature ceramsite) in the second rotary kiln 13 can be tumbled and conveyed, and the material can also be lifted during the conveying process. This design can fully and uniformly calcine the phosphogypsum. In the initial stage of contact between the phosphogypsum and the high-temperature ceramsite, it is easier to make full use of the heat of the high-temperature ceramsite to achieve crystallization of the phosphogypsum, preventing over-burning of the phosphogypsum while avoiding under-burning, and ensuring that the modified gypsum with better quality is obtained by calcination.

[0059] In practical applications, one or more spiral conveyor plates 131 can be installed inside the second rotary kiln 13, without specific limitations. At the same time, not only can each lifting plate 132 extend along the axial direction of the second rotary kiln 13, but multiple lifting plates 132 can also be installed and evenly arranged along the circumference of the second rotary kiln 13. The lifting plates 132 and the spiral conveyor plates 131 can be connected to each other or set separately, without specific limitations.

[0060] Meanwhile, by setting the lifting plate 132 to extend along the axial direction of the second rotary kiln 13, the radial height of the lifting plate 132 relative to the inner wall of the second rotary kiln 13 can be set to be no higher than 1 / 3 of the radial height of the spiral conveyor plate 131 relative to the inner wall of the second rotary kiln 13. This design can ensure that the setting of the lifting plate 132 will not affect the normal conveying of materials in the second rotary kiln 13 by the spiral conveyor plate 131. Furthermore, based on the dust-raising effect of the lifting plate 132, the problem of high-temperature ceramsite and phosphogypsum not being able to mix and contact well can be effectively solved. For example, during the material rotation process, high-temperature ceramsite rises while phosphogypsum falls, resulting in low heating efficiency of phosphogypsum.

[0061] In some embodiments, such as Figure 7 and Figure 8 As shown, the rotary kiln system 1 of the present invention further includes: a flue gas chamber 14, the flue gas chamber 14 includes a flue gas chamber body 141 and a dust removal structure 142 disposed in the flue gas chamber body 141, the dust removal structure 142 is used to remove dust from the flue gas. The flue gas chamber body 141 has a flue gas inlet 1401, an ash discharge port 1402 and a flue gas outlet 1403. The flue gas inlet 1401 is connected to the kiln head of the first rotary kiln 11. The ash discharge port 1402 is used to discharge the dust intercepted in the dust removal structure 142 during the flue gas dust removal process. The flue gas outlet 1403 is used to discharge the gas after the dust removal structure 142 has removed the dust.

[0062] It is understandable that by using the exhaust chamber 14 to remove dust from the high-temperature flue gas generated in the first rotary kiln 11 during the calcination of ceramsite, the clean emission of flue gas can be achieved to a certain extent, preventing dust-laden flue gas from polluting the environment.

[0063] In practical applications, the dust removal structure 142 includes multiple baffles, which are spaced apart within the smoke chamber body 141 to define a serpentine flow channel within the smoke chamber body 141. Multiple ash discharge ports 1402 can be provided, located at the bottom of the smoke chamber body 141 and connected to the serpentine flow channel. The serpentine flow channel can be considered as a gas flow channel that repeatedly bends relative to a certain reference line.

[0064] It is understandable that multiple baffles are spaced apart to divide multiple compartments within the smoke chamber body 141. However, since any two adjacent baffles are staggered along a set direction (e.g., horizontal direction), adjacent compartments are connected to each other, thereby connecting multiple compartments in sequence to form a serpentine flow channel.

[0065] Meanwhile, the ash discharge port 1402 is used to collect dust or particulate matter falling from the serpentine flow channel and to discharge the collected dust or particulate matter. Multiple ash discharge ports 1402 are arranged one-to-one with multiple chambers. Switch valves can be installed at the ash discharge ports 1402 to control the discharge of dust or particulate matter collected at the ash discharge ports 1402.

[0066] In some embodiments, such as Figure 1 and Figure 2 As shown, the integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat of the product, as shown in this invention, further includes: a water scrubbing tower 4 and a multi-stage sedimentation tank 5; the air inlet of the negative pressure fan 3 and the water scrubbing tower 4 are connected, the water scrubbing tower 4 is used to wash the gas discharged from the negative pressure fan 3, and the liquid outlet of the water scrubbing tower 4 is connected to multiple sedimentation tanks 5, for example, the liquid outlet of the water scrubbing tower 4 is connected to at least one of the multiple sedimentation tanks 5, and the sedimentation tank 5 is used to precipitate gypsum in the liquid discharged from the liquid outlet.

[0067] Understandably, the water washing of the exhaust gas from the negative pressure fan 3 by the water scrubbing tower 4 can remove dust and some unrecovered phosphogypsum contained in the exhaust gas, thus achieving air discharge. In practical applications, an induced draft fan can be installed at the top exhaust port of the water scrubbing tower 4 to drive the discharge of clean air after water washing by the water scrubbing tower 4.

[0068] Meanwhile, the multi-stage sedimentation tanks 5 are connected sequentially, with the first sedimentation tank 5 connected to the drain outlet of the water scrubbing tower 4. By setting up multiple sedimentation tanks 5, the hydrated phosphogypsum after washing can undergo a hydration reaction and fully precipitate. This precipitated phosphogypsum can be recycled again and sent to the rotary kiln system 1 for further calcination, modification, and sorting. The combined use of the water scrubbing tower 4 and the multi-stage sedimentation tanks 5 helps to improve the recovery rate of the finished product (modified phosphogypsum), ensuring the energy saving and environmental protection of the entire gypsum treatment production line.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated device for calcining, modifying, and sorting phosphogypsum using waste heat from product processing, characterized in that, include: A rotary kiln system for mixing high-temperature ceramsite with phosphogypsum to heat the phosphogypsum; The sorting and dust removal system includes a sorting device and a cyclone dust collector. The sorting device includes a sorting chamber and a screening structure disposed within the sorting chamber. The sorting chamber has a gas outlet, a material recovery port, a first sorting port, and a second sorting port. The discharge end of the rotary kiln system extends into the sorting chamber and is connected to the screening structure. The first sorting port is used to collect the undersize material from the screening structure and to receive the material recovered from the material recovery port. The second sorting port is used to collect the oversize material from the screening structure. The air inlet of the cyclone dust collector is connected to the gas outlet, and the discharge port of the cyclone dust collector is connected to the material recovery port through an airlock discharge valve. A negative pressure fan is connected to the air outlet of the cyclone dust collector to extract air from the cyclone dust collector.

2. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 1, is characterized in that... The screening structure is a cylindrical screen, and the first end of the cylindrical screen is connected to the discharge end of the rotary kiln system. The discharge end of the rotary kiln system drives the cylindrical screen to rotate. The first sorting port is located on the lower side of the cylindrical screen, and the second sorting port is located opposite to the second end of the cylindrical screen.

3. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 1, is characterized in that... The sorting device and the cyclone dust collector are an integrated structure and are housed inside an insulated protective cover.

4. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 1, is characterized in that... The rotary kiln system includes: The first rotary kiln is used to heat the ceramsite to obtain high-temperature ceramsite. The mixing chamber includes a housing, a guide channel, and a feed channel. The guide channel is inclinedly disposed within the housing. The tail of the first rotary kiln extends into the housing and communicates with the upper end of the guide channel. The first end of the feed channel is located outside the housing, and the second end of the feed channel is disposed within the housing and communicates with the middle of the guide channel. The first end of the feed channel is used to input the phosphogypsum. The second rotary kiln has its kiln head extending into the box body and communicating with the lower end of the material guide channel. The kiln tail of the second rotary kiln serves as the discharge end of the rotary kiln system.

5. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 4, is characterized in that... A fuel input pipe is inserted at the kiln tail of the first rotary kiln. The fuel input pipe is configured to feed biomass fuel into the kiln tail of the first rotary kiln under the drive of compressed air, so as to calcine the ceramsite in the first rotary kiln based on the combustion of the biomass fuel. The second rotary kiln is equipped with a vent pipe at its kiln head. The vent pipe is used to introduce air into the second rotary kiln to aid combustion of hydrogen formed by the water-gas reaction and organic matter obtained by the thermal decomposition of phosphogypsum.

6. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 4, is characterized in that... The material guide channel is equipped with a backstop structure; The anti-reverse structure includes multiple baffles, all of which are disposed on the top wall of the material guide channel and arranged sequentially along the material conveying direction of the material guide channel; the baffles extend downward at an angle toward the bottom wall of the material guide channel, and the extension direction of the baffles forms an acute angle with the material conveying direction of the material guide channel.

7. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 4, is characterized in that... The tail of the first rotary kiln is equipped with a distribution stacker, which is used to transport the high-temperature ceramsite in the first rotary kiln to the material guide channel. The distributed material stacker includes multiple spiral guide plates, which are arranged sequentially along the circumference of the tail of the first rotary kiln, and a discharge channel is formed between two adjacent spiral guide plates.

8. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in claim 4, is characterized in that... The second rotary kiln is equipped with a spiral conveyor and multiple lifting plates; The spiral conveyor plate is disposed on the inner wall of the second rotary kiln and extends along a spiral trajectory relative to the central axis of the second rotary kiln; a plurality of the lifting plates are disposed on the inner wall of the second rotary kiln and located near the kiln head of the second rotary kiln, and each of the lifting plates extends along the axial direction of the second rotary kiln. The radial height of the lifting plate relative to the inner wall of the second rotary kiln is lower than the radial height of the spiral conveyor plate relative to the inner wall of the second rotary kiln.

9. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in any one of claims 4 to 8, is characterized in that... The rotary kiln system also includes: A smoke exhaust chamber includes a chamber body and a dust removal structure disposed within the chamber body, the dust removal structure being used for dust removal treatment of flue gas; The flue gas chamber body has a flue gas inlet, an ash discharge port, and a flue gas outlet. The flue gas inlet is connected to the kiln head of the first rotary kiln. The ash discharge port is used to discharge the dust intercepted in the flue gas dust removal process by the dust removal structure. The flue gas outlet is used to discharge the gas after dust removal by the dust removal structure.

10. The integrated equipment for calcining, modifying, and sorting phosphogypsum using waste heat from the product, as described in any one of claims 1 to 8, is characterized in that... Also includes: Water scrubbing towers and multi-stage sedimentation tanks; The negative pressure fan and the air inlet of the water shower tower are connected. The water shower tower is used to wash the gas discharged by the negative pressure fan. The liquid outlet of the water shower tower is connected to multiple sedimentation tanks. The sedimentation tanks are used to precipitate gypsum in the liquid discharged from the liquid outlet.

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