Clean production process of compound fertilizer

Abstract

The invention discloses a clean production process of a compound fertilizer, which comprises the following steps: carrying out primary granulation on raw materials to obtain granular raw materials; proportioning and mixing the granular raw materials to obtain a mixture; the mixture is crushed; carrying out secondary granulation; the raw materials are directly granulated and put in storage, so that the obvious defects of moisture absorption, hardening and deterioration easily caused by raw material storage in a compound fertilizer plant are overcome, the worry of long-term storage of the raw materials is fundamentally solved, the use area and conditions of a production plant are optimized, and the granulated granular raw materials can be stored in a large scale in a storage form of a new process. The contact area between particles is reduced, the volume compression density is increased, wet gas is not easy to enter, a series of practical problems of material overflow, dust splashing, corrosion caused by the fact that materials absorb moisture and adhere to production equipment and the like in traditional compound fertilizer production are well solved, and the requirements of green factories and clean production are well met. And the whole process is simple and efficient.

Description

Technical Field

[0001] The invention relates to the field of waste material production, in particular to a clean production process of compound fertilizer. Background Art

[0002] Compound fertilizer refers to chemical fertilizer containing two or more nutrient elements of nitrogen, phosphorus and potassium. Compound fertilizer has the advantages of high nutrient content, few by-components and good physical properties. It plays a very important role in balanced fertilization, improving fertilizer utilization and promoting high and stable yields of crops.

[0003] At present, the existing production methods of compound fertilizer mainly include high tower granulation and agglomeration granulation. High tower granulation can realize the production of part of fertilizers, and its raw materials need to be liquefiable, and the liquefaction temperature is relatively sensitive. Commonly used, such as urea, has corresponding requirements for raw materials, and thus there are production limitations; in the production process of agglomeration granulation, most of the raw materials are inorganic salts, which are easy to absorb moisture, harden, liquefy and other properties, and the appearance is small particles, powder and other forms. The current manufacturers simply store the purchased packaging bags in an open raw material warehouse. Moisture absorption, hardening, and liquidization to produce a muddy environment often occur and cannot be solved. In addition, the dust phenomenon is serious during the production process, resulting in a poor overall production environment and causing a certain degree of environmental pollution, which needs further improvement. Summary of the invention

[0004] In order to ensure the versatility of production and reduce environmental pollution, the present application provides a clean production process for compound fertilizer.

[0005] The present application provides a clean production process for compound fertilizer, which adopts the following technical solution: A clean production process for compound fertilizer comprises the following steps: S1, granulating the raw materials once to obtain granular raw materials; S2, batching and mixing the granular raw materials to obtain a mixed material; S3, crushing the mixture; S4, performing secondary granulation; S5, screening and post-processing.

[0006] Optionally, the granular raw material obtained in step S1 is stored in a sealed raw material warehouse.

[0007] Optionally, the post-processing in step S5 includes drying, curing and coating.

[0008] Optionally, in step S5, a screening machine is used for screening, and the screening residue is transported as return material to step S4 for granulation again.

[0009] Optionally, in the batching process of step S2, each single particle raw material is fed into a batching storage box to form a basic weight unit, and then transferred into a mixer for mixing, with a stirring speed of 8-30 rpm and a stirring time of 8-15 minutes.

[0010] Optionally, the diameter of the raw material particles obtained in step S1 is 5-30 mm.

[0011] Optionally, inclined closed pipes are used for transportation between each step and process, and the pipes are high-pressure vinyl chloride pipes or high-pressure polypropylene pipes.

[0012] Optionally, an isolation layer is provided in the pipe fitting, the upper part of the isolation layer is a material flow layer, the lower part of the isolation layer is a compressed air flow layer, and the isolation layer is provided with dense perforations.

[0013] Optionally, the moisture content of the finished product after drying is less than 3%.

[0014] Optionally, an exhaust device and a dehumidification device are provided on the top of the raw material warehouse, and the inner wall of the raw material warehouse is coated with a resin coating.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. The raw materials are directly granulated and stored, which solves the obvious drawbacks of compound fertilizer plant raw materials storage that are prone to moisture absorption, compaction and deterioration, fundamentally solves the worries of long-term storage of raw materials, and optimizes the use area and conditions of the production plant; 2. The storage form of the new process can store granular raw materials in large quantities. The contact area between particles is reduced, and the volume compression density is increased, which makes it difficult for humid gas to enter. Combined with the wind ball and dehumidifier in the raw material warehouse, it not only greatly overcomes the problem of raw materials absorbing moisture and hardening due to bagging ventilation, but also enhances the fluidity of raw materials, creating a foundation for the automation system of computer batching and electronic metering feeding; 3. The new process has made a thorough improvement on the stubborn environmental pollution problem in the current production and transportation links. That is, a closed high-pressure vinyl chloride pipe or high-pressure polypropylene pipe is used as the main conveying body, with a partition lined inside, and compressed air is introduced to produce directional flow, driving the granular materials to flow smoothly along the set inclination angle. This new type of inclined trough angle pipeline transportation overcomes material blockage and solves the corrosion and environmental pollution problems commonly existing in inorganic salts in the raw materials of compound fertilizer production; 4. This process overcomes a series of practical problems in traditional compound fertilizer production, such as material overflow, dust splashing, and corrosion caused by material adhering to production equipment due to moisture absorption, and meets the requirements of green factories and clean production. Moreover, the whole process is simple and efficient, with fewer granulating equipment and auxiliary facilities, and the energy consumption is significantly lower than that of other types of production, thus directly reducing production costs; 5. The granular raw materials after granulation have consistent appearance. After extrusion, the air in the raw materials is removed and the gaps are compressed, so that the density and specific gravity of the formed particles tend to be uniform. This kind of raw materials will not cause stratification due to particle size, density difference and different adsorption capacity when blended. The compound fertilizer after blending conforms to the internationally accepted principle of blended fertilizer ratio and can meet the quality requirements of homogenized and fully blended fertilizer, which not only saves processing costs and improves production efficiency, but also enables the subsequent simple compound fertilizer to be realized, which may form a new fertilizer production model. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of Example 1.

[0017] Figure 2 It is a cross-sectional view of the silo in Example 1.

[0018] Figure 3 It is a structural diagram of the blanking chute in Example 1.

[0019] Figure 4 It is a schematic diagram of the structure of the conveying device in Example 1.

[0020] Figure 5 It is a structural diagram of the chute gas delivery mechanism in Example 1.

[0021] Figure 6 It is a structural diagram of the chute gas delivery mechanism in Example 2.

[0022] Figure 7 It is a schematic diagram of the internal structure of the chute gas delivery mechanism in Example 3.

[0023] Figure 8 It is a cross-sectional view of the blockage clearing member in Example 3.

[0024] Fig. 9 It is a structural diagram of the wind ball in Example 3.

[0025] Description of reference numerals: 1. Silo; 2. Silo body; 3. Feed inlet; 4. Discharge outlet; 5. Stop valve; 6. Drop chute; 7. Sidewall; 8. Vibration motor; 9. Wind ball; 10. Bag; 11. Shell; 12. Elevator; 13. Chute gas conveying mechanism; 14. Pipe fittings; 15. Isolation layer; 16. Material flow layer; 17. Compressed air flow layer; 18. Perforation; 19. Gas storage tank; 20. Inlet pipe; 21. Return pipe; 22. Feed pipe; 23 , discharge end; 24, one-way valve; 25, pressure relief valve; 26, dust box; 27, channel; 28, filter bag; 29, movable plate; 30, telescopic rod; 31, tension spring; 32, blockage clearing piece; 33, impeller; 34, cam; 35, cone; 36, scraper; 37, rotating blade; 38, slide; 39, return spring; 40, inclined surface; 41, cylinder; 42, extension; 43, fan; 44, ventilation port; 45, vertical rod. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1-9 This application is described in further detail.

[0027] Example 1 A clean production process for compound fertilizer, such as Figure 1 As shown, it mainly includes the following steps: S1, raw material part; The basic raw materials purchased by the production enterprises from the raw material supply place, the raw materials for compound fertilizer production are mostly inorganic salts, such as potassium sulfate ammonium sulfate, potassium chloride ammonium chloride, ammonium phosphate potassium magnesium phosphate, ammonium bicarbonate, urea, etc. For example, the classic compound fertilizer nitrogen, phosphorus and potassium nutrient combination ratio is 18-18-18. It means that it contains 18% nitrogen, 18% phosphorus pentoxide, and 18% potassium oxide.

[0028] S2, primary granulation; It means that in the new process, the purchased raw materials are directly processed into particles with a diameter of 5-30mm under the action of the double-roll granulator according to the design, and then transferred to the silos of different storage warehouses for storage.

[0029] S3, silo; The materials are placed in silos for storage according to their different particle forms. In this embodiment, the raw material warehouse adopts a silo 1 .

[0030] S4, batching / metering / feeding; According to the actual required ingredient ratio, the simple granular raw materials in the simple raw material warehouse are accurately fed into the ingredient storage box to form a basic weight unit and then transferred to the next raw material mixing process; for example, the nitrogen, phosphorus and potassium nutrient ratio is 18-18-18, and the simple raw materials in the simple raw material warehouse are batched by computer and the electronic metering feeder outputs the simple raw materials in the above ratio.

[0031] S5, mixed; The metered materials are mixed in a mixer for about 10 minutes at a stirring speed of 8-30 rpm to ensure uniform mixing of the materials.

[0032] S6, broken; The mixed material is transferred into a double-roll crusher for crushing, and crushed into a mixed material with a preset particle size distribution; S7, secondary granulation; The crushed mixture is then transferred to a 4-5mm double-roll granulator for secondary granulation to obtain new particles with a diameter of 4-5mm; S8, screening; The particles after the secondary granulation enter the screening machine for screening, and those that meet the particle size are transferred to the next process. The screening residue is transported to step S7 as return material for re-granulation.

[0033] S9, drying, curing, and coating; The drying adopts a large-scale rotary drum drying form with a diameter of 1.8-2.6 meters. Due to the effect of the inclination angle, the raw materials enter from the upper end and flow to the lower end. The dry hot air (100-130 degrees) enters from the lower end and exits from the upper end to form convection for heat exchange, drying out the moisture in the material and taking it away, so that the moisture content of the finished product is less than 3%. The materials with lower melting points in the raw materials are recrystallized due to softening and liquefaction, producing relatively solid crystals, so that the particle strength is improved; some varieties (such as controlled release fertilizers) need to be coated on the surface to make them have a delayed release function. The coating membrane materials include starch modified materials, cellulose film materials, resin film materials, etc.

[0034] S10, packaging and warehousing; The finished compound fertilizer that has completed the set process can be directly transferred to the bag packaging section, or it can be transferred to a large-scale finished product warehouse for storage and then packaged into bags according to demand at a later time.

[0035] like Figure 2 and Figure 3 As shown, it is a silo 1 used in step S3, the silo 1 includes a vertical silo body 2 and an internal buffering dropping device, a top side of the silo body 2 is provided with a feed port 3, a bottom of the silo body 2 is provided with a discharge port 4 and a stop valve 5 is provided at the discharge port 4, the buffering dropping device includes a spiral downward dropping chute 6, one side of the dropping chute 6 is fixed to the inner wall of the silo body 2, and the other side is provided with a rib 7, the rib 7 is used to block the material, so that the material entering from the feed port 3 can stably slide down the dropping chute 6 to the bottom for storage, avoiding the situation where the material particles are broken due to vertical falling.

[0036] The inner wall of the silo 2 and the surface of the blanking chute 6 are coated with resin coatings and other barrier coatings to prevent moisture absorption and reduce friction to facilitate flow; in addition, a vibration motor 8 is provided at the discharge port 4 at the bottom of the silo 2, and vibration can be generated by the vibration motor 8 to ensure that the material in the silo can be discharged from the discharge port 4 in an orderly manner, reducing the occurrence of blockage.

[0037] like Figure 2 As shown, an exhaust device is arranged on the top of the warehouse body 2, and the exhaust device adopts a wind ball 9, through which good ventilation between the warehouse body 2 and the outside is achieved. In addition, a dehumidification device is also connected to the warehouse body 2, and the dehumidification device adopts a dehumidifier, through which the warehouse can be effectively dehumidified, and a cloth bag 10 is arranged at the end of the wind ball 9 extending into the warehouse body 2. With the help of the cloth bag 10, internal dust can be blocked from being discharged, thereby effectively preventing dust from rising.

[0038] This storage method for granular raw materials solves a series of drawbacks caused by the traditional fertilizer production enterprises storing bagged raw materials on high racks, which are very easy to absorb moisture, and the environment has been greatly improved.

[0039] The above processes involve the transportation of granular raw materials, such as Figure 4 As shown, it is a conveying device for transporting and conveying granular raw materials, which comprises a shell 11, an elevator 12 and a chute gas conveying mechanism 13. The elevator 12 and the chute gas conveying mechanism 13 are both located in the shell 11, and the elevator 12 and the chute gas conveying mechanism 13 are alternately and continuously distributed, so that the material is in a closed environment in the shell during the conveying process, which effectively reduces the dust phenomenon, and thus can well improve the external workshop environment. In actual use, the elevator 12 can be used with the chute gas conveying mechanism 13 as a conveying group, and multiple conveying groups are set according to the distance between the processes to finally achieve the purpose of material transportation. The elevator 12 is used to lift the material from the bottom to a high place, and the material lifted to a high place is then dropped and fed through the chute gas conveying mechanism 13, and the purpose of good feeding is achieved in this cycle; in addition, a pressure relief valve 25 is provided on the shell 11, and when the pressure in the closed shell exceeds the set value, the pressure can be relieved in time through the pressure relief valve 25.

[0040] like Figure 5As shown, the chute gas conveying mechanism 13 includes an inclined pipe 14, which is made of a high-pressure vinyl chloride pipe or a high-pressure polypropylene pipe. An isolation layer 15 is arranged inside the pipe 14. The upper part of the isolation layer 15 is a material flow layer 16, and the lower part of the isolation layer 15 is a compressed air flow layer 17. The isolation layer 15 is provided with dense perforations 18, which are evenly distributed on the isolation layer 15, and the aperture of the perforations 18 is smaller than the diameter of the material particles. The closed high-pressure vinyl chloride pipe or high-pressure polypropylene pipe is used as the conveying body, and the interior is lined with an isolation layer 15. The compressed air is introduced to generate a directional flow, which drives the granular material to flow smoothly along the set inclination angle. This new type of chute inclination pipeline conveying overcomes the material blockage and solves the corrosion and environmental pollution problems commonly existing in inorganic salts in the raw materials of compound fertilizer production. On the one hand, the material can fall under its own gravity, and on the other hand, the compressed air plays a further role in the conveying of the material, ensuring that the granular material can fall well and be conveyed forward.

[0041] like Figure 5 As shown, the chute gas conveying mechanism 13 also includes an air storage tank 19, an air inlet pipe 20 and an air return pipe 21. A feed pipe 22 is provided on the top of the upper end of the pipe fitting 14, and the lower end of the pipe fitting 14 serves as a discharge end 23. One end of the air inlet pipe 20 is connected to the air storage tank 19, and the other end is connected to the compressed air flow layer 17 at the upper end of the pipe fitting 14. One end of the air return pipe 21 is connected to the compressed air flow layer 17 at the lower end of the pipe fitting 14, and the other end is connected to the air inlet pipe 20. Both the air inlet pipe 20 and the air return pipe 21 are provided with a one-way valve 24. A large amount of compressed air is stored in the air storage tank 19. In actual use, part of the compressed air can flow back to the air inlet pipe 20 through the air return pipe 21 for reuse, thereby realizing the recycling of compressed air, reducing waste, and achieving a more energy-saving purpose.

[0042] In short, the new production process of compound fertilizer meets the requirements of green factory (clean production), and the overall procedure is simple and efficient. It has advantages that are difficult to overcome in traditional compound fertilizer production, which are specifically reflected in the following aspects: 1. Direct granulation and storage of raw materials solves the obvious drawbacks of moisture absorption, compaction and deterioration of raw materials in compound fertilizer plants, fundamentally solves the problem of long-term storage of raw materials, and optimizes the use area and conditions of production plants.

[0043] 2. The storage form of the new process can store granular raw materials in large quantities. The contact area between particles is reduced, and the volume compression density is increased, making it difficult for humid gas to enter. In addition, the exhaust device and dehumidification device not only greatly overcome the problem of raw materials absorbing moisture and hardening due to bagging permeability, but also enhance the fluidity of the raw materials, creating a foundation for the automated system of computer batching and electronic metering feeding.

[0044] 3. Large-scale raw material storage mode saves the land area for raw material storage. Single-element granular materials can realize computer-controlled automatic batching, feeding and electronic metering and discharging.

[0045] 4. The 4-5mm particles of the primary granulation formed by roller extrusion have a consistent appearance. The air in the raw materials is eliminated by extrusion, and the gaps are compressed, so that the density and specific gravity of the formed particles tend to be uniform. This kind of raw material will not cause stratification due to particle size, density difference and different adsorption capacity when blending. The blended compound fertilizer meets the internationally accepted principle of blended fertilizer ratio and can meet the quality requirements of fully homogenized blended fertilizer, which not only saves processing costs and improves production efficiency, but also enables the subsequent simple compound fertilizer to be realized, which may form a new fertilizer production model.

[0046] 5. The new process has made a thorough improvement on the stubborn environmental pollution problem in the current production and transportation links. That is, a closed high-pressure vinyl chloride pipe or high-pressure polypropylene pipe is used as the main conveying body, and a partition is lined inside. Compressed air is introduced to produce directional flow, driving the granular material to flow smoothly along the set inclination angle. This new inclined trough angle pipeline transportation overcomes the material blockage and solves the corrosion and environmental pollution problems commonly found in inorganic salts in the raw materials of compound fertilizer production.

[0047] 6. The main difficulties for compound fertilizer production enterprises to achieve green factory (clean production) standards are: first, environmental indicators are difficult to achieve (such as the air particle index in the production workshop is less than 10mg / m3); the current three major production methods (high tower granulation, agglomeration granulation, and roller extrusion granulation) are difficult to overcome a series of practical problems such as material overflow, dust splashing, and corrosion caused by moisture absorption of materials and adhesion to production equipment.

[0048] 7. Realization of new green factory (clean production) Due to the simple and efficient process, there are relatively few granulation equipment and auxiliary facilities, and the energy consumption is significantly lower than other types of production energy consumption, which directly reduces the production cost.

[0049] 8. The new one-time granulation mode overcomes the product defects caused by various drawbacks of previous blended fertilizers and can fully realize the automated production of blended fertilizers. From foreign examples, blended fertilizers are the most economical production mode of compound fertilizers. This method may bring about beneficial changes in the production of compound fertilizers and will promote the realization of intensive, simplified, low-energy and diversified production of compound fertilizers.

[0050] Example 2 A clean production process for compound fertilizer, such as Figure 6As shown, the difference between it and Example 1 mainly lies in the difference of the chute gas conveying mechanism 13. In this embodiment, a dust box 26 is arranged on the return air pipe 21 of the chute gas conveying mechanism 13, and a channel 27 for communicating with the return air pipe 21 is arranged in the dust box 26, and a filter bag 28 is arranged in the channel 27. Since some powder materials are inevitably generated during the transportation of particulate materials, these powder materials will flow into the return air pipe 21. The design of the filter bag 28 can filter the powder materials to avoid the situation where the powder materials continue to flow in the pipeline and accumulate more and more. In this embodiment, two dust boxes 26 are arranged horizontally in parallel, and the dust boxes 26 are horizontally slidably connected to the return air pipe 21. When a large amount of powder materials accumulates in one dust box 26, another dust box 26 is switched to be connected to the return air pipe 21 by sliding. At this time, the powder materials in the dust box 26 can be cleaned, and the return air pipe 21 can be kept in a working state continuously, and the production efficiency will not be affected by cleaning the powder materials.

[0051] Example 3 A clean production process for compound fertilizer, such as Figure 7 As shown, in this embodiment, a movable plate 29 is arranged inside the pipe 14 at a position corresponding to the compressed air flow layer 17, and the movable plate 29 is connected to the pipe 14 by sliding in the direction of the isolation layer 15. The movable plate 29 is movably connected to the inner wall of the pipe 14 by means of telescopic rods 30 on both sides, and a tension spring 31 connecting the pipe 14 and the movable plate 29 is arranged between the pipe 14 and the movable plate 29. The tension spring 31 is used to drive the movable plate 29 to reset away from the isolation layer 15. A clearing member 32 corresponding to the through hole 18 on the isolation layer 15 is arranged on the movable plate 29, and the clearing member 32 is used to clear the through hole 18. A driving source for driving the movable plate 29 to move toward the isolation layer 15 is arranged in the pipe 14, and the driving source includes an impeller 33. The impeller 33 is arranged in the compressed air flow layer 17. When the compressed air flows in the compressed air flow layer 17, the impeller 33 is driven to rotate. A cam 34 is fixed on the central axis of the impeller 33. The cam 34 is used to press the movable plate 29 to drive it to move toward the isolation layer 15. In this way, as the impeller 33 continues to rotate, the movable plate 29 can be driven to move back and forth. The clearing member 32 is inserted back and forth into the through-hole 18 to clear the blockage of the through-hole 18, thereby avoiding the situation where the powder in the granular material causes the blockage of the through-hole 18 and affects the transportation due to long-term use, and the convenience of clearing is realized. The movement of the movable plate 29 can transmit vibration to the isolation layer 15, thereby improving the feeding effect of the granular material on the isolation layer 15.

[0052] like Figure 7 and Figure 8As shown, the clearing piece 32 includes a cone 35 at the top, and scrapers 36 are arranged on both sides of the clearing piece 32. The clearing piece 32 is rotatably connected to the movable plate 29, and a rotating blade 37 is fixed to the bottom end of the clearing piece 32, so that the compressed air flow can drive the rotating blade 37 to rotate, thereby making the clearing piece 32 rotate synchronously. When the clearing piece 32 rotates, the scrapers 36 on both sides thereof can scrape off the powder adhered to the inner wall of the perforation 18, so as to achieve a better clearing effect.

[0053] like Figure 8 As shown, the scraper 36 is horizontally slidably connected to the clearing piece 32, and a slide groove 38 for the clearing piece 32 to slide horizontally is provided on the side wall of the clearing piece 32. A return spring 39 is provided in the slide groove 38 to drive the clearing piece 32 to move outward and return to its original position, and the top of the scraper 36 has an inclined surface 40, which ensures that the clearing piece 32 can enter the perforation 18 more smoothly when the movable plate 29 moves upward, and the movable scraper 36 can adapt well to the partial deviation of the aperture of the perforation 18 and has better applicability.

[0054] like Figure 7 As shown, the impeller 33 is vertically lifted and connected to the pipe 14, and a cylinder 41 is provided on the pipe 14 to drive the impeller 33 to vertically lift and lower, so that the position of the impeller 33 can be adjusted. When there is no need to clear the blockage, the impeller 33 can be driven downward by the cylinder 41 so that the cam 34 does not contact the isolation layer 15, thereby maintaining a good ventilation effect of the isolation layer 15 and reducing the situation where the cam 34 contacts the movable plate 29 and continuously generates impact noise.

[0055] like Fig. 9 As shown, in this embodiment, the bottom end of the wind ball 9 has an extension portion 42 for extending into the silo 1, and a fan 43 is arranged in the extension portion 42. The air outlet direction of the fan 43 is toward the wind ball 9. With the help of further design of the fan 43, the air flow efficiency can be improved, and the ventilation effect of the wind ball 9 can be improved. The bottom end of the extension portion 42 is an air exchange port 44, and a cloth bag 10 is arranged at the air exchange port 44. The cloth bag 10 is used to block and suppress the discharge of dust in the silo 1, and dust is effectively prevented; in addition, a vertical rod 45 is arranged on the fan 43, and the bottom end of the vertical rod 45 abuts against the cloth bag 10. The vibration generated when the fan 43 is working can be transmitted to the cloth bag 10 through the vertical rod 45, causing the cloth bag 10 to shake, so that the dust adhering to the cloth bag 10 can be shaken off, avoiding the clogging of the cloth bag 10 and affecting the ventilation effect, thereby realizing automatic clearing of the cloth bag 10.

[0056] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A clean production process for compound fertilizer, characterized in that: The following steps are involved: S1, granulating the raw materials once to obtain granular raw materials; S2, batching and mixing the granular raw materials to obtain a mixed material; S3, crushing the mixture; S4, performing secondary granulation; S5, screening and post-processing.

2. A clean production process for compound fertilizer according to claim 1, characterized in that: The granular raw material obtained in step S1 is stored in a sealed raw material warehouse.

3. A clean production process for compound fertilizer according to claim 2, characterized in that: The post-processing in step S5 includes drying, curing and coating.

4. A clean production process for compound fertilizer according to claim 2, characterized in that: In step S5, a screening machine is used for screening, and the screening residue is transported as return material to step S4 for granulation again.

5. A clean production process for compound fertilizer according to claim 1, characterized in that: In the batching process of step S2, each single particle raw material is fed into a batching storage box to form a basic weight unit, and then transferred to a mixer for mixing, with a stirring speed of 8-30 rpm and a stirring time of 8-15 minutes.

6. A clean production process for compound fertilizer according to claim 1, characterized in that: The diameter of the raw material particles obtained in step S1 is 5-30 mm.

7. A clean production process for compound fertilizer according to claim 1, characterized in that: An inclined closed pipe (14) is used for transportation between each step and process, and the pipe (14) is a high-pressure vinyl chloride pipe or a high-pressure polypropylene pipe.

8. A clean production process for compound fertilizer according to claim 7, characterized in that: An isolation layer (15) is arranged inside the pipe (14), the upper part of the isolation layer (15) is a material flow layer (16), the lower part of the isolation layer (15) is a compressed air flow layer (17), and the isolation layer (15) is provided with densely distributed perforations (18).

9. A clean production process for compound fertilizer according to claim 3, characterized in that: The moisture content of the finished product after drying is less than 3%.

10. The clean production process of compound fertilizer according to claim 2, characterized in that: An exhaust device and a dehumidification device are arranged on the top of the raw material warehouse, and the inner wall of the raw material warehouse is coated with a resin coating.

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