Efficient roasting system and using method thereof

Abstract

The invention discloses an efficient roasting system which comprises a tunnel kiln, the tunnel kiln comprises a preheating zone, a firing zone, a cooling zone and rails arranged at the bottoms of the preheating zone, the firing zone and the cooling zone, the preheating zone, the firing zone and the cooling zone are communicated in sequence, a coal feeding and air supply system is arranged on the firing zone, an ash removal system is arranged at the kiln outlet position of the cooling zone, and the ash removal system is communicated with a waste heat recovery system; the coal feeding and air supply system comprises a double-helix crushing mechanism, and a feeding mechanism and an air distribution mechanism which are communicated with the double-helix crushing mechanism, the air distribution mechanism comprises coal injection pipes, the coal injection pipes are arranged at the top and the side edge of the firing zone, and the axis height of the coal injection pipes arranged at the side edge of the firing zone corresponds to the lower half part of the phosphate ore purification block blank. By adopting the coal feeding and air supplying system, the problems of non-uniform kiln section temperature, underburning of products, overburning and the like caused by manual coal feeding in full external combustion roasting in the prior art can be avoided, the yield is larger than or equal to 95%, and the coal feeding and air supplying system is suitable for ore roasting.

Description

Technical Field

[0001] This invention belongs to the field of phosphate rock purification technology, and in particular relates to a high-efficiency roasting system and its usage method. Background Technology

[0002] Phosphate rock is an important chemical mineral raw material with irreplaceable strategic importance to my country. It is a core pillar of national food security, energy transformation, industrial upgrading, and resource security. my country's phosphate rock resources are mainly low- to medium-grade phosphate rock, with scarce rich ore resources. It is mainly sedimentary phosphate rock, but this type of ore is difficult to beneficiate and requires various beneficiation processes to meet the standards for use.

[0003] Currently, the main phosphate rock beneficiation processes both domestically and internationally include flotation, scrubbing and desliming, gravity separation, and roasting / digestion. Phosphate rock roasting is a pretreatment process that uses high-temperature treatment to remove specific impurities (mainly carbonates and organic matter), thereby improving ore quality or reactivity. Existing phosphate rock roasting systems mainly utilize rotary kilns, fluidized bed furnaces, and multi-layer roasting furnaces / vertical shaft furnaces. However, different roasting methods have different problems. Rotary kilns suffer from relatively low thermal efficiency, uneven material distribution, and high dust content; fluidized bed furnaces have high requirements for raw material particle size, high dust content, and difficulty in handling large pieces of material; multi-layer roasting furnaces / vertical shaft furnaces have limited processing capacity, inflexible temperature control, and uneven local reactions, while the high dust content can contaminate the phosphate rock raw material.

[0004] Therefore, a high-efficiency roasting system is provided to meet the existing requirements for phosphate rock roasting. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-efficiency roasting system. This high-efficiency roasting system, by incorporating a coal feeding and air supply system with a double-helix crushing mechanism, can improve the fineness of pulverized coal to increase thermal efficiency. Combined with the designed position of the pulverized coal injection pipe, it ensures uniform heating of the purified phosphate rock lumps, effectively increasing the phosphorus extraction rate of the phosphate rock. This solves the problems of low thermal efficiency, easy contamination of raw materials, and uneven roasting reaction during the phosphate rock purification process.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a high-efficiency roasting system, characterized in that it includes a tunnel kiln, wherein the tunnel kiln includes a preheating zone, a firing zone, a cooling zone connected in sequence, and a track set at the bottom of the preheating zone, the firing zone, and the cooling zone, wherein a kiln car is provided on the track, a coal feeding and air supply system is provided on the firing zone, and an ash removal system is provided at the kiln exit position of the cooling zone, wherein the ash removal system is connected to a waste heat recovery system; The coal feeding and air supply system includes a double-helix crushing mechanism and a feeding mechanism and an air distribution mechanism connected to the double-helix crushing mechanism. The air distribution mechanism includes a pulverized coal injection pipe, which is set at the top and side of the firing zone. The axial height of the pulverized coal injection pipe set on the side of the firing zone corresponds to the lower half of the phosphate rock purification block placed on the kiln car.

[0007] The above-mentioned high-efficiency roasting system is characterized in that the double-helix crushing mechanism includes a connected air regulating pipe and a crushing chamber, the crushing chamber is formed by a cylindrical particle size screen and a shell fixedly connected to both ends of the particle size screen, and the crushing chamber is provided with a number of crushing hammers and a cylindrical crushing disc, the two ends of the crushing disc being fixedly connected to the inner wall of the crushing chamber shell. The hydraulic breaker includes an inner hydraulic breaker, an outer hydraulic breaker, and a hammer handle. The inner hydraulic breaker is located inside the crushing disc, and the outer hydraulic breaker extends out of the crushing disc. The crushing disc has an annular discharge port to provide a channel for the rotation of the hammer handle. The hammer handle is connected to the output shaft of a first motor. An air regulating valve is provided on the air regulating pipe.

[0008] The above-mentioned high-efficiency roasting system is characterized in that a material spreading disc is fixedly connected to the side of the hammer handle near the air regulating pipe.

[0009] The above-mentioned high-efficiency roasting system is characterized in that discharge teeth are provided on both sides of the annular discharge port.

[0010] The aforementioned high-efficiency roasting system is characterized in that the air distribution mechanism includes an air distribution mechanism shell, a guide wheel disposed inside the air distribution mechanism shell, and two pulverized coal injection pipe connection ports disposed on the air distribution mechanism shell. The axis of the guide wheel coincides with the axis of the particle size screen, and the output shaft of the first motor passes through the axis of the guide wheel and is fixedly connected to the guide wheel. The two pulverized coal injection pipe connection ports are respectively located on both sides of the guide wheel, and several pulverized coal injection holes are opened on the pulverized coal injection pipe connection ports for communicating with the pulverized coal injection pipe. The particle size screen is covered with a cylindrical wear-resistant liner.

[0011] The above-mentioned high-efficiency roasting system is characterized in that the feeding mechanism includes a feeding hopper and a screw conveyor connected together, the screw conveyor is connected to a double screw crushing mechanism, a power mechanism is provided on the screw conveyor, a vibrating motor is provided on the feeding hopper, and a feeding hopper gate valve is provided at the connection between the feeding hopper and the screw conveyor.

[0012] The above-mentioned high-efficiency roasting system is characterized in that the power mechanism includes a second motor, a first pulley fixedly connected to the output shaft of the second motor, and a second pulley connected to the first pulley via a belt, wherein the second pulley is fixedly connected to the screw shaft of the screw conveyor.

[0013] The above-mentioned high-efficiency calcination system is characterized in that the ash removal system includes an ash removal chamber, the top and side walls of which are provided with a number of ash removal nozzles, and the end of the ash removal chamber away from the cooling zone is provided with a number of ash removal fans. The end of the ash removal chamber near the cooling zone is connected to a waste heat recovery system. The waste heat recovery system includes an air collection duct, a dust concentration measuring device and a dust collector installed on the air collection duct, one end of which is located in the ash removal chamber and the other end is located in the preheating zone.

[0014] The aforementioned high-efficiency roasting system is characterized in that the dust removal nozzles whose axial extension lines pass through the phosphate ore purification lumps are fan-shaped nozzles, and the dust removal nozzles whose axial extension lines pass through the gaps between the phosphate ore purification lumps are circular nozzles.

[0015] This invention also discloses a method for using the above-mentioned high-efficiency roasting system for purified phosphate rock blocks, characterized by comprising the following steps: Step 1: Stack the purified phosphate rock blocks on the kiln car to obtain purified phosphate rock block blanks. Step 2: The purified phosphate rock lumps obtained in Step 1 are fed into a tunnel kiln. After passing through the preheating zone, firing zone, and cooling zone for roasting, they enter the ash removal system to remove dust and residual heat from the surface of the purified phosphate rock lumps. Step 3: The dust and residual heat removed in Step 2 are collected by the waste heat recovery system. The heat is then sent into the preheating zone through the waste heat recovery system, and the purified phosphate rock billets are then pushed out of the dust removal system.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The high-efficiency roasting system of the present invention, by adopting a coal feeding and air supply system, can avoid the problems of uneven kiln cross-section temperature, under-burning and over-burning of products caused by manual coal feeding in the existing technology of all-external combustion roasting, so as to achieve a yield of ≥95%.

[0017] 2. This invention improves thermal efficiency by setting up a coal feeding and air supply system with a double-helix crushing mechanism, which increases the fineness of coal powder. Combined with the design of the coal injection pipe position and the use of purified phosphate rock lumps as raw material, the air containing coal powder envelops the purified phosphate rock lumps, ensuring uniform temperature within the firing zone and uniform heating of the purified phosphate rock lumps, effectively increasing the phosphorus extraction rate by 30%. During roasting, the phosphate rock is enveloped by hot air, preventing a large amount of dust from adhering to the surface of the phosphate rock. The complete combustion of coal powder reduces the ash content, thus reducing the dust content during roasting. The use of lumpy phosphate rock prevents ash from entering the interior, making the phosphate rock less susceptible to contamination. The designed ash removal system quickly removes dust from the surface of the roasted phosphate rock, preventing dust from polluting the environment.

[0018] 3. The coal feeding and air supply system of the present invention can crush coal powder to a particle size of ≤100 mesh, and the air-coal ratio is adjustable. It can reduce the moisture content of coal powder from 5% to 1%~2%. When the coal powder enters the combustion zone, the high temperature causes the small amount of water in the coal powder to rapidly vaporize and expand, and the coal powder particles are more easily dispersed, so that the combustion efficiency reaches more than 99%. Compared with manual coal feeding, the efficiency is increased by more than 80% and coal is saved by 40%~50%.

[0019] 4. By setting up a coal feeding and air supply system with a double-helix crushing mechanism, this invention can use coarser coal powder with a particle size of 1mm to 3mm, avoiding the problem of easy explosion when fine coal powder is transported, and ensuring safe production.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the high-efficiency roasting system of the present invention.

[0022] Figure 2 This is a partial cross-sectional structural diagram of the coal feeding and ventilation system of the present invention.

[0023] Figure 3 This is a cross-sectional view of the double-helix crushing mechanism of the present invention.

[0024] Figure 4 This is a side view of the crushing chamber of the present invention.

[0025] Figure 5 This is a schematic diagram of the annular discharge port of the present invention.

[0026] Figure 6 This is a side view of the air distribution mechanism of the present invention.

[0027] Explanation of reference numerals in the attached figures: 1—Tunnel kiln; 2—Coal feeding and air supply system; 21—Crushing chamber; 211—Particle size screen; 212—Crushing chamber shell; 213—Crusher hammer; 214—Crushing disc; 215—Inner crusher hammer; 216—Outer crusher hammer; 217—Annular discharge port; 218—First motor; 22—Air regulating pipe; 221—Air regulating valve; 23—Paper spreading disc; 24—Air distribution mechanism shell; 241—Wear-resistant liner; 25—Guide wheel; 26—Spraying... 27—Coal pipe connection port; 28—Pulverized coal injection pipe; 28—Feeding hopper; 281—Vibrating motor; 282—Feeding hopper gate valve; 29—Screw conveyor; 291—Second motor; 292—First pulley; 293—Second pulley; 3—Dust removal system; 31—Dust removal chamber; 311—Dust removal nozzle; 312—Dust removal fan; 4—Waste heat recovery system; 41—Air collection duct; 411—Dust concentration measuring instrument; 412—Dust collector. Detailed Implementation

[0028] Example 1 like Figure 1 As shown, the high-efficiency roasting system of this embodiment includes a tunnel kiln 1. The tunnel kiln 1 includes a preheating zone, a firing zone, a cooling zone, and a track set at the bottom of the preheating zone, the firing zone, and the cooling zone in sequence. A kiln car is provided on the track. A coal feeding and air supply system 2 is provided on the firing zone. An ash removal system 3 is provided at the kiln exit position of the cooling zone. The ash removal system 3 is connected to a waste heat recovery system 4. The coal feeding and air supply system 2 includes a double-helix crushing mechanism and a feeding mechanism and an air distribution mechanism connected to the double-helix crushing mechanism. The air distribution mechanism includes a pulverized coal injection pipe 27, which is set at the top and side of the firing zone. The axial height of the pulverized coal injection pipe 27 set on the side of the firing zone corresponds to the lower half of the phosphate rock purification block placed on the kiln car.

[0029] In practical use, this embodiment employs a tunnel kiln 1 with a preheating zone, a firing zone, and a cooling zone to roast and purify phosphate rock. Tracks are installed at the bottom of the preheating zone, firing zone, and cooling zone to allow kiln cars loaded with phosphate rock to move along the tracks, with a top-mounted machine providing power for the kiln car movement. A coal feeding and air supply system 2 is installed in the firing zone to inject pulverized coal into the firing zone to provide roasting heat. A dust removal system 3 and a waste heat recovery system 4 are installed at the kiln exit to collect dust and heat from the surface of the roasted phosphate rock. The coal powder is further refined by the double-helix crushing mechanism of the coal feeding and air supply system 2 to improve combustion efficiency. The coal powder enters the double-helix crushing mechanism for crushing via a connected feeding mechanism and air distribution mechanism, and then enters the firing zone through the pulverized coal injection pipe 27 of the air distribution system. The pulverized coal injection pipe 27 is positioned at the top and sides of the firing zone, and the axial height of the pulverized coal injection pipe 27 on the side of the firing zone is limited to correspond to the lower half of the phosphate rock purification lump (in this embodiment, the axial height of the pulverized coal injection pipe 27 on the side of the firing zone is the kiln...). Above the top of the kiln car, 0.38m to 0.5m, the height of the phosphate rock purified lumps stacked on the top of the kiln car is 1.5m, the width is 1m, and the gap between two adjacent phosphate rock purified lumps is 0.15m. The top pulverized coal injection pipe 27 can deliver air containing pulverized coal to the bottom of the firing zone. While delivering heat to the bottom of the firing zone, the air at the bottom of the firing zone can be swirled in combination with the air from the side pulverized coal injection pipe 27, which together drive the mixing of hot and cold air, making the firing temperature in the firing zone more uniform.

[0030] like Figures 2-4As shown, further, in this embodiment, the double-helix crushing mechanism includes a connected air regulating pipe 22 and a crushing chamber 21. The crushing chamber 21 is formed by a cylindrical particle size screen 211 and a crushing chamber shell 212 fixedly connected to both ends of the particle size screen 211. The crushing chamber 21 is provided with a plurality of sets of crushing hammers 213 and a cylindrical crushing disc 214. Both ends of the crushing disc 214 are fixedly connected to the inner wall of the crushing chamber shell 212. The hydraulic breaker 213 includes an inner hydraulic breaker 215, an outer hydraulic breaker 216, and a hammer handle. The inner hydraulic breaker 215 is located inside the crushing disc 214, and the outer hydraulic breaker 216 extends out of the crushing disc 214. The crushing disc 214 has an annular discharge port 217 to provide a channel for the rotation of the hammer handle. The hammer handle is connected to the output shaft of the first motor 218. An air regulating valve 221 is provided on the air regulating pipe 22.

[0031] In actual use, in this embodiment, by setting up an air regulating pipe 22 and a crushing chamber 21, the coal powder conveyed by the feeding mechanism enters the crushing chamber 21 through the air regulating pipe 22 for refining; by using a cylindrical particle size screen 211 and a crushing chamber shell 212 to form the crushing chamber 21, the refined coal powder can only leave the particle size screen 211 and enter the air distribution mechanism after reaching a suitable particle size (particle size ≤ 100 mesh); by setting up several sets of crushing hammers 213, the crushing efficiency is improved, and the several sets of crushing hammers 213 are coaxial; By setting up an inner breaker 215, an outer breaker 216, and a crushing disc 214, in this embodiment, one end of the hammer handle is fixedly connected to the inner breaker 215, and the outer breaker 216 is fixedly connected to the inner breaker 215. This allows the coal powder to be crushed by the inner breaker 215 first after entering the crushing disc 214, and then enter the space between the crushing disc 214 and the particle size screen 211, where it is further crushed by the outer breaker 216. The annular discharge port 217 opened on the crushing disc 214 allows the hammer handle to rotate smoothly and provides a channel for the coal powder to enter the crushing range of the outer breaker 216. The other end of the hammer handle is fixedly connected to the output shaft of the first motor 218 to provide power for the movement of the breaker 213. By setting an air regulating valve 221 to adjust the air-coal ratio, the coal powder can achieve complete combustion. In this embodiment, a fan is connected to the air regulating valve 221 to provide dispersed air for the coal powder.

[0032] like Figure 2 As shown, in this embodiment, a material spreading disc 23 is fixedly connected to the side of the hammer handle near the air regulating pipe 22.

[0033] In actual use, in this embodiment, the spreading disc 23 is a triangular plate, with one side of the triangular plate fixedly connected to the hammer handle, so that the spreading disc 23 is driven to rotate by the hammer handle, thereby dispersing the coal powder into the crushing chamber 21.

[0034] like Figure 5As shown, in this embodiment, discharge teeth are provided on both sides of the annular discharge port 217.

[0035] In actual use, in this embodiment, discharge teeth are provided on both sides of the annular discharge port 217 to control the size of coal powder and prevent larger particles from entering the screening section between the particle size screen 211 and the crushing disc 214; the wind and vibration generated when the crusher hammer 213 rotates can cause the coal powder attached to the discharge teeth to fall off, and the coal powder can be thrown out during the rotation process.

[0036] like Figure 2 and Figure 6 As shown, further, in this embodiment, the air distribution mechanism includes an air distribution mechanism housing 24, a guide wheel 25 disposed inside the air distribution mechanism housing 24, and two pulverized coal injection pipe connection ports 26 disposed on the air distribution mechanism housing 24. The axis of the guide wheel 25 coincides with the axis of the particle size screen 211, and the output shaft of the first motor 218 passes through the axis of the guide wheel 25 and is fixedly connected to the guide wheel 25. The two pulverized coal injection pipe connection ports 26 are respectively located on both sides of the guide wheel 25. A plurality of pulverized coal injection holes are opened on the pulverized coal injection pipe connection ports 26 for communicating with the pulverized coal injection pipe 27. The particle size screen 211 is covered with a cylindrical wear-resistant liner 241.

[0037] In practical use, in this embodiment, a guide vane 25 is used to blow the coal powder entering from the particle size screen 211 toward the two coal injection pipe connection ports 26. The axis of the guide vane 25 is aligned with the axis of the particle size screen 211, and the output shaft of the first motor 218 passes through the axis of the guide vane 25 and is fixedly connected to the guide vane 25, so that the first motor 218 provides power for the rotation of the guide vane 25. Under the action of the guide vane 25, the coal powder is further driven through the coal injection pipe 27 connected to the coal injection pipe connection port 26 and enters the firing zone. A cylindrical wear-resistant liner 241 is provided on the outer sleeve of the particle size screen 211 to reduce the wear of the coal powder on the outer shell 24 of the air distribution mechanism. At the same time, in this embodiment, the diameter of the wear-resistant liner 241 is smaller than the diameter of the guide vane 25, so that the coal powder is concentrated and sent to the guide vane 25. In this embodiment, the blades of the guide vane 25 are equipped with a detachable fan for ash removal.

[0038] like Figure 2 As shown, further, in this embodiment, the feeding mechanism includes a feeding hopper 28 and a screw conveyor 29 connected together. The screw conveyor 29 is connected to the double screw crushing mechanism. A power mechanism is provided on the screw conveyor 29. A vibration motor 281 is provided on the feeding hopper 28. A feeding hopper gate valve 282 is provided at the connection between the feeding hopper 28 and the screw conveyor 29.

[0039] In actual use, in this embodiment, coal powder is loaded into the feeding hopper 28 and the screw conveyor 29 are set up, and then transported to the double screw crushing mechanism by the screw conveyor 29; a vibration motor 281 is set on the feeding hopper 28 to vibrate during the coal powder feeding process to achieve continuous feeding; a feeding hopper gate valve 282 is set at the connection between the feeding hopper 28 and the screw conveyor 29 to control the coal powder feeding amount, thereby controlling the coal-air ratio.

[0040] like Figure 2 As shown, in this embodiment, the power mechanism includes a second motor 291, a first pulley 292 fixedly connected to the output shaft of the second motor 291, and a second pulley 293 connected to the first pulley 292 via a belt. The second pulley 293 is fixedly connected to the screw shaft of the screw conveyor 29.

[0041] In actual use, this embodiment sets a first pulley 292 on the output shaft of the second motor 291 and a second pulley 293 connected to the first pulley 292 by a belt. The second pulley 293 is fixedly connected to the screw shaft of the screw conveyor 29 to provide power to the screw conveyor 29 and realize the screw conveying and pre-dispersion of coal powder.

[0042] like Figure 1 As shown, further, in this embodiment, the dust removal system 3 includes a dust removal chamber 31, and a plurality of dust removal nozzles 311 are provided on the top and side walls of the dust removal chamber 31. A plurality of dust removal fans 312 are provided at the end of the dust removal chamber 31 away from the cooling zone. The end of the dust removal chamber 31 near the cooling zone is connected to a waste heat recovery system 4. The waste heat recovery system 4 includes an air collection duct 41, a dust concentration measuring device 411 and a dust collector 412 provided on the air collection duct 41. The dust collector 412 is farther away from the dust removal chamber 31 than the dust concentration measuring device 411. One end of the air collection duct 41 is located inside the dust removal chamber 31, and the other end is located inside the preheating zone.

[0043] In practical use, this embodiment provides several cleaning nozzles 311 on the top and side walls of the cleaning chamber 31, and several cleaning fans 312 at the end of the cleaning chamber 31 away from the cooling zone. The cleaning nozzles 311 are connected to fans to ensure that the surface of the phosphate ore purification lumps is completely covered by air, thereby improving heat recovery efficiency and dust removal efficiency. By connecting the end of the cleaning chamber 31 near the cooling zone to the waste heat recovery system 4, the air after the cleaning nozzles 311 and cleaning fans 312 exchange heat with the phosphate ore purification lumps enters the waste heat recovery system 4. In this embodiment, the number of cleaning fans 312 is set according to the size of the cleaning chamber 31, so that the airflow of the cleaning fans 312 completely covers the cross-section of the cleaning chamber 31, thereby improving heat recovery and dust removal efficiency. The air collection duct 41 is used to collect heat from the cleaning chamber and cooling zone. The dust concentration measuring device 411 is used to measure the dust concentration. When the dust concentration drops to the set concentration, the cleaning nozzle 311 and cleaning fan 312 are closed. The dust collector 412 is used to provide suction so that the hot air from the cleaning chamber 31 and the cooling zone enters the air collection duct 41 and is sent into the preheating zone after dust removal.

[0044] like Figure 1 As shown, further, in this embodiment, the cleaning nozzle 311 whose axis extends through the phosphate ore purification lumps is a fan-shaped nozzle, and the cleaning nozzle 311 whose axis extends through the gap between the phosphate ore purification lumps is a circular nozzle.

[0045] In practical use, in this embodiment, the nozzle shape is set according to the position of the phosphate rock purification lumps. When the extended axis of the cleaning nozzle 311 passes through the phosphate rock purification lumps, that is, the cleaning nozzle 311 is facing the phosphate rock purification lumps, it is set as a fan-shaped nozzle to blow out a large area of ​​air; when the extended axis of the cleaning nozzle 311 passes through the gap between the phosphate rock purification lumps, that is, the cleaning nozzle 311 is facing the gap between the phosphate rock purification lumps, it is set as a circular nozzle to blow out directional air, and the wind speed is controlled at 15m / s~20m / s, so that the air circulation in the gap between each phosphate rock purification lumps is accelerated, effectively reducing the temperature between the phosphate rock purification lumps; in this embodiment, the bottom surface of the cleaning chamber 31 is provided with a positioning track, which can fix the stopping position of the kiln car. Combined with the fixed stacking method, it is ensured that the position of the nozzle corresponds to the position of the lumps, and the number of cleaning nozzles 311 is set according to the air outlet coverage area of ​​the cleaning nozzles 311 to ensure that the surface of the phosphate rock purification lumps is covered by air.

[0046] Example 2 This embodiment uses the high-efficiency roasting system of Example 1 to roast phosphate rock purification blocks. The phosphate rock purification blocks are pressed green bodies prepared by the compression molding method of phosphate rock purification in Chinese Invention Patent "A Method for Compression Molding of Phosphate Rock for Purification" (Publication No. CN119263230A). The roasting of the phosphate rock purification blocks includes the following steps: Step 1: Stack the purified phosphate rock blocks on the kiln car to obtain purified phosphate rock block blanks. Step 2: The phosphate rock purified lumps obtained in Step 1 are fed into the tunnel kiln 1. After passing through the preheating zone, firing zone and cooling zone for roasting, they enter the dust removal chamber 31 to remove dust and residual heat from the surface of the phosphate rock purified lumps. The dust on the surface of the phosphate rock purified lumps is blown to the dust collector 412 for dust removal. The dust concentration is measured using the dust concentration measuring device 411. When the dust concentration drops to the set concentration, the dust removal operation is stopped. Step 3: The dust and residual heat removed in Step 2 are collected by the residual heat recovery system 4, and hot air is sent into the preheating zone through the air collection duct 41. Then, the purified phosphate rock billets are pushed out of the dust removal system 3.

[0047] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A high-efficiency roasting system, characterized in that, The tunnel kiln (1) includes a preheating zone, a firing zone, a cooling zone, and a track connected in sequence at the bottom of the preheating zone, the firing zone, and the cooling zone. A kiln car is provided on the track. A coal feeding and air supply system (2) is provided on the firing zone. A ash removal system (3) is provided at the kiln exit position of the cooling zone. The ash removal system (3) is connected to a waste heat recovery system (4). The coal feeding and air supply system (2) includes a double spiral crushing mechanism and a feeding mechanism and an air distribution mechanism connected to the double spiral crushing mechanism. The air distribution mechanism includes a pulverized coal injection pipe (27). The pulverized coal injection pipe (27) is set at the top and side of the firing zone, and the axial height of the pulverized coal injection pipe (27) set on the side of the firing zone corresponds to the lower half of the phosphate rock purification block placed on the kiln car.

2. The high-efficiency roasting system according to claim 1, characterized in that, The double-helix crushing mechanism includes a connected air regulating pipe (22) and a crushing chamber (21). The crushing chamber (21) is formed by a cylindrical particle size screen (211) and a crushing chamber shell (212) fixedly connected to both ends of the particle size screen (211). The crushing chamber (21) is provided with several sets of crushing hammers (213) and a cylindrical crushing disc (214). The two ends of the crushing disc (214) are fixedly connected to the inner wall of the crushing chamber shell (212). The hydraulic breaker (213) includes an inner hydraulic breaker (215), an outer hydraulic breaker (216), and a hammer handle. The inner hydraulic breaker (215) is located inside the crushing disc (214), and the outer hydraulic breaker (216) extends out of the crushing disc (214). The crushing disc (214) has an annular discharge port (217) to provide a channel for the rotation of the hammer handle. The hammer handle is connected to the output shaft of the first motor (218). An air regulating valve (221) is provided on the air regulating pipe (22).

3. The high-efficiency roasting system according to claim 2, characterized in that, A material spreading disc (23) is fixedly connected to the side of the hammer handle near the air regulating pipe (22).

4. The high-efficiency roasting system according to claim 2, characterized in that, Discharge teeth are provided on both sides of the annular discharge port (217).

5. The high-efficiency roasting system according to claim 2, characterized in that, The air distribution mechanism includes an air distribution mechanism housing (24), a guide wheel (25) disposed inside the air distribution mechanism housing (24), and two coal injection pipe connection ports (26) disposed on the air distribution mechanism housing (24). The axis of the guide wheel (25) coincides with the axis of the particle size screen (211), and the output shaft of the first motor (218) passes through the axis of the guide wheel (25) and is fixedly connected to the guide wheel (25). The two coal injection pipe connection ports (26) are located on both sides of the guide wheel (25), and several coal injection holes are opened on the coal injection pipe connection ports (26) for communicating with the coal injection pipe (27). The particle size screen (211) is covered with a cylindrical wear-resistant liner (241).

6. The high-efficiency roasting system according to claim 1, characterized in that, The feeding mechanism includes a feeding hopper (28) and a screw conveyor (29) connected together. The screw conveyor (29) is connected to the double screw crushing mechanism. A power mechanism is provided on the screw conveyor (29). A vibration motor (281) is provided on the feeding hopper (28). A feeding hopper gate valve (282) is provided at the connection between the feeding hopper (28) and the screw conveyor (29).

7. The high-efficiency roasting system according to claim 6, characterized in that, The power mechanism includes a second motor (291), a first pulley (292) fixedly connected to the output shaft of the second motor (291), and a second pulley (293) connected to the first pulley (292) via a belt. The second pulley (293) is fixedly connected to the screw shaft of the screw conveyor (29).

8. The high-efficiency roasting system according to claim 1, characterized in that, The dust removal system (3) includes a dust removal chamber (31), and a number of dust removal nozzles (311) are provided on the top and side walls of the dust removal chamber (31). A number of dust removal fans (312) are provided at the end of the dust removal chamber (31) away from the cooling zone. The end of the dust removal chamber (31) near the cooling zone is connected to a waste heat recovery system (4). The waste heat recovery system (4) includes an air collection duct (41), a dust concentration measuring device (411) and a dust collector (412) provided on the air collection duct (41). The dust collector (412) is farther away from the dust removal chamber (31) than the dust concentration measuring device (411). One end of the air collection duct (41) is located inside the dust removal chamber (31), and the other end is located inside the preheating zone.

9. The high-efficiency roasting system according to claim 8, characterized in that, The cleaning nozzle (311) whose axis extends through the phosphate ore purification lumps is a fan-shaped nozzle, and the cleaning nozzle (311) whose axis extends through the gap between the phosphate ore purification lumps is a circular nozzle.

10. A method of using the high-efficiency roasting system for phosphate rock purification blocks as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Stack the purified phosphate rock blocks on the kiln car to obtain purified phosphate rock block blanks. Step 2: The phosphate rock purified lumps obtained in Step 1 are sent into the tunnel kiln (1). After passing through the preheating zone, the firing zone and the cooling zone for roasting, they enter the ash removal system to remove dust and residual heat from the surface of the phosphate rock purified lumps. Step 3: The dust and residual heat removed in Step 2 are collected by the residual heat recovery system (4). The heat is sent into the preheating zone through the residual heat recovery system (4), and then the phosphate rock purification billet is pushed out of the dust removal system.

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