Multi-component particle aggregation aid for extruded compound fertilizer production as well as preparation method and use method of multi-component particle aggregation aid

Abstract

The invention discloses a multi-component particle aggregation aid for extruded compound fertilizer production and a preparation method and a use method thereof, the multi-component particle aggregation aid comprises the following components by mass percent: 12-16% of polyvinyl alcohol, 4-8% of isocyanate, 54-72% of filler, 2-4% of magnesium sulfate heptahydrate and 10-18% of starch, and the use method comprises the following steps: 1, diluting and blending: adding the multi-component particle aggregation aid and a solvent into a stirrer according to a mass ratio of 1: 30-1: 60, stirring, adding the solvent into the stirrer, and stirring to obtain a mixed solution; a multi-component particle aggregation auxiliary agent solution is obtained; 2, slurry spraying operation: uniformly spraying the multi-component aggregate additive solution on the surfaces of the compound fertilizer coarse particles through a slurry spraying roller, controlling the slurry spraying pressure to be 0.2-0.4 MPa, and controlling the slurry spraying amount of the multi-component aggregate additive solution per ton of the compound fertilizer coarse particles to be 1-6%. The granulation rate and the particle strength of the compound fertilizer particles can be improved, and the quality and the production efficiency of the compound fertilizer particles can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of compound fertilizer production technology, and in particular to a multi-component granulation aid for extruded compound fertilizer production, its preparation method, and its application method. Background Technology

[0002] Compound fertilizer is a widely used fertilizer in modern agriculture. It contains two or more major nutrients, designed to provide balanced nutrients needed for crop growth, promoting healthy plant growth and increasing yield. Making compound fertilizer into granules not only improves the uniformity and convenience of application in the field but also effectively reduces dusting and losses caused by powder during transportation and use. Extrusion granulation is a production method for compound fertilizer. It involves mixing various raw materials and using an extruder to obtain regularly shaped coarse granules, which are then processed through spraying and drying to obtain the final compound fertilizer product. In the spraying process, a spraying roller, along with a prepared slurry, is used to spray the coarse granules produced by the extruder, softening the granules and initially shaping and rounding them to obtain granules with better roundness. However, existing compound fertilizer granules have insufficient granulation rate and strength, resulting in low quality and low production efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a multi-component granulation aid for extruded compound fertilizer production, its preparation method and application method, which can improve the granulation rate and granule strength of compound fertilizer granules, and effectively improve the quality and production efficiency of compound fertilizer granules.

[0004] To achieve the above-mentioned technical objectives and related technical objectives, the present invention provides a multi-component granulation additive for extrusion compound fertilizer production, which comprises the following components in the following mass percentages: polyvinyl alcohol 12-16%, isocyanate 4-8%, filler 54-72%, magnesium sulfate heptahydrate 2-4%, and starch 10-18%.

[0005] In one example of the multi-component granulation additive for extruded compound fertilizer production of the present invention, the polyvinyl alcohol includes one or both of polyvinyl alcohol PVA2488 and PVA1788.

[0006] In one example of the multi-component granulation additive for extruded compound fertilizer production of the present invention, the filler includes one or both of titanium dioxide and sodium sulfate.

[0007] In one example of the multi-component granulation aid for extruded compound fertilizer production of the present invention, the starch includes one or both of corn starch and cassava starch.

[0008] The preparation method of the multi-component granulation aid for extruded compound fertilizer production of the present invention includes adding the following components in the indicated mass percentages: 12-16% polyvinyl alcohol, 4-8% isocyanate, 54-72% filler, 2-4% magnesium sulfate heptahydrate, and 10-18% starch into a mixer and mixing for 1-3 hours. Then, the mixture is sieved using a 100-300 mesh filter sieve to obtain the multi-component granulation aid.

[0009] The method of using the multi-component granulation aid for extruded compound fertilizer production of the present invention includes: 1. Dilution and preparation: Add the multi-component granulation agent and solvent to a mixer at a mass ratio of 1:30 to 1:60, and stir at room temperature for 0.5 to 2 hours to obtain a multi-component granulation agent solution; 2. Spraying operation: The multi-component granulation agent solution is evenly sprayed onto the surface of the compound fertilizer coarse particles through a spraying roller. The spraying pressure is controlled at 0.2-0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of compound fertilizer coarse particles is controlled at 1-6%.

[0010] In one example of the method of using the multi-component granulation aid for extrusion compound fertilizer production of the present invention, the solvent is water, and the mass ratio of the multi-component granulation aid to the solvent is 1:30 to 1:40.

[0011] In one example of the method of using the multi-component granulation aid for extruding compound fertilizer production according to the present invention, the spraying amount of the multi-component granulation aid solution per ton of compound fertilizer coarse particles is controlled to be 3-6%.

[0012] The multi-component granulation aid for extruded compound fertilizer production of this invention has excellent adhesive properties. After being sprayed onto the surface of coarse compound fertilizer particles, it can enhance the bonding force between the various raw materials of the compound fertilizer. In the granulation process, it can effectively improve the granulation rate of compound fertilizer and significantly improve the particle strength of compound fertilizer particles, giving the compound fertilizer particles higher hardness and compressive strength. During the transportation, storage and use of compound fertilizer, the compound fertilizer particles are not easily broken or pulverized, ensuring the integrity of the compound fertilizer particles. The compound fertilizer particles are also more regular, round, and have a more uniform particle size distribution. After the granulation rate and particle strength of compound fertilizer are improved, the production efficiency of compound fertilizer is improved, rework and energy consumption are reduced, thereby reducing the overall production cost. Detailed Implementation

[0013] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0014] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0015] This invention provides a multi-component granulation additive for extruded compound fertilizer production, comprising the following components by weight percentage: polyvinyl alcohol 12-16%, isocyanate 4-8%, filler 54-72%, magnesium sulfate heptahydrate 2-4%, and starch 10-18%. The polyvinyl alcohol includes one or both of polyvinyl alcohol PVA2488 and PVA1788. The filler includes one or both of titanium dioxide and sodium sulfate. The starch includes one or both of corn starch and tapioca starch.

[0016] The preparation method of the multi-component granulation aid for extruded compound fertilizer production of the present invention includes adding the following components in the indicated mass percentages: 12-16% polyvinyl alcohol, 4-8% isocyanate, 54-72% filler, 2-4% magnesium sulfate heptahydrate, and 10-18% starch into a mixer and mixing for 1-3 hours. Then, the mixture is sieved using a 100-300 mesh filter sieve to obtain the multi-component granulation aid.

[0017] The method of using the multi-component granulation aid for extruded compound fertilizer production of the present invention includes: 1. Dilution and preparation: Add the multi-component granulation agent and solvent to a mixer at a mass ratio of 1:30 to 1:60, and stir at room temperature for 0.5 to 2 hours to obtain a multi-component granulation agent solution; 2. Spraying operation: The multi-component granulation agent solution is evenly sprayed onto the surface of the compound fertilizer coarse particles through a spraying roller. The spraying pressure is controlled at 0.2-0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of compound fertilizer coarse particles is controlled at 1-6%.

[0018] In one example of the method for using the multi-component granulator in the production of extruded compound fertilizer according to the present invention, the solvent is water, and the mass ratio of the multi-component granulator to the solvent is 1:30 to 1:40. The spraying amount of the multi-component granulator solution per ton of coarse compound fertilizer particles is controlled to be 3 to 6%.

[0019] The present invention will be further described below through several embodiments. It should be noted that, unless otherwise specified, the materials, reagents and equipment used in the embodiments can all be purchased through commercial means.

[0020] Example 1: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 1 hour: polyvinyl alcohol (PVA2488) 12%, isocyanate 4%, titanium dioxide 72%, magnesium sulfate heptahydrate 2%, and tapioca starch 10%. The mixture was then sieved through a 100-mesh sieve to obtain the multi-component granulation aid. The multi-component granulation aid and water were added to a mixer at a mass ratio of 1:30 and mixed at room temperature for 1 hour to obtain a multi-component granulation aid solution.

[0021] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-element granulating agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.2 MPa, and the spraying amount of multi-element granulating agent solution per ton of coarse compound fertilizer particles is controlled at 1%. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0022] Example 2: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 2 hours: polyvinyl alcohol (PVA1788) 13%, isocyanate 5%, sodium sulfate 68%, magnesium sulfate heptahydrate 2%, and corn starch 12%. The mixture was then sieved through a 200-mesh sieve to obtain the multi-component granulation aid. The multi-component granulation aid and water were then added to a mixer at a mass ratio of 1:40 and mixed at room temperature for 2 hours to obtain a multi-component granulation aid solution.

[0023] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-element granulation agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying amount of multi-element granulation agent solution per ton of coarse compound fertilizer particles is controlled at 2%.

[0024] 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0025] Example 3: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 3 hours: polyvinyl alcohol (PVA1788) 14%, isocyanate 6%, titanium dioxide 63%, magnesium sulfate heptahydrate 3%, and tapioca starch 14%. The mixture was then sieved through a 300-mesh sieve to obtain the multi-component granulation aid. The multi-component granulation aid and water were added to a mixer at a mass ratio of 1:60 and mixed at room temperature for 0.5 hours to obtain a multi-component granulation aid solution.

[0026] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-component agglomerating agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying amount of multi-component agglomerating agent solution per ton of coarse compound fertilizer particles is controlled at 3%. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0027] Example 4: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 3 hours: polyvinyl alcohol (PVA2488) 15%, isocyanate 7%, sodium sulfate 58%, magnesium sulfate heptahydrate 3%, and tapioca starch 17%. The mixture was then sieved through a 300-mesh sieve to obtain the multi-component granulation aid. The multi-component granulation aid and water were added to a mixer at a mass ratio of 1:30 and mixed at room temperature for 2 hours to obtain a multi-component granulation aid solution.

[0028] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-component granulation agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of coarse compound fertilizer particles is controlled at 4%. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0029] Example 5: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 3 hours: polyvinyl alcohol (PVA2488) 16%, isocyanate 8%, titanium dioxide 54%, magnesium sulfate heptahydrate 4%, and corn starch 18%. The mixture was then sieved using a 300-mesh filter to obtain the multi-component granulation aid. The multi-component granulation aid and water were added to a mixer at a mass ratio of 1:30 and mixed at room temperature for 2 hours to obtain a multi-component granulation aid solution.

[0030] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-component granulation agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of coarse compound fertilizer particles is controlled at 5%. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0031] Example 6: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 3 hours: polyvinyl alcohol (PVA2488) 8%, polyvinyl alcohol (PVA1788) 8%, isocyanate 8%, titanium dioxide 25%, sodium sulfate 29%, magnesium sulfate heptahydrate 4%, corn starch 9%, and tapioca starch 9%. The mixture was then sieved through a 300-mesh sieve to obtain the multi-component granulation aid. The multi-component granulation aid and water were added to a mixer at a mass ratio of 1:30 and mixed at room temperature for 2 hours to obtain a multi-component granulation aid solution.

[0032] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-component granulation agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of coarse compound fertilizer particles is controlled at 6%. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0033] Example 7: The preparation steps of a multi-component granulation aid for extruded compound fertilizer production are as follows: The following components by mass percentage were added to a mixer and mixed for 3 hours: polyvinyl alcohol (PVA2488) 7%, polyvinyl alcohol (PVA1788) 5%, isocyanate 4%, titanium dioxide 32%, sodium sulfate 40%, magnesium sulfate heptahydrate 2%, corn starch 4%, and tapioca starch 6%. The mixture was then sieved through a 300-mesh sieve to obtain the multi-component granulation aid. The multi-component granulation aid and water were added to a mixer at a mass ratio of 1:30 and mixed at room temperature for 2 hours to obtain a multi-component granulation aid solution.

[0034] The steps for producing compound fertilizer granules using multi-component granulation aids for extruded compound fertilizer production include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where the multi-component granulation agent solution is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of coarse compound fertilizer particles is controlled at 6%. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0035] Comparative Example The steps involved in producing compound fertilizer granules include: 1. In accordance with the production formula requirements, urea, monoammonium phosphate, potassium chloride, potassium sulfate, ammonium chloride, ammonium sulfate, and auxiliary materials are sequentially added to the designated silos; 2. Weigh each raw material using a belt weighing scale, and then transport the weighed raw materials to the crushing and mixing machine via a raw material collection belt conveyor. The crushing and mixing machine is used to fully crush and mix the raw materials. 3. The mixture obtained in step 2 is conveyed to the humidifying mixer via the conveying equipment. An appropriate amount of water is added to the mixture and it is thoroughly mixed. The uniformly mixed material is then fed into multiple extruders via the material distribution scraper for extrusion granulation to obtain compound fertilizer coarse granules. 4. After the coarse compound fertilizer particles are screened by the drum screen, the fine powder is transported back to the humidifying mixer. The coarse compound fertilizer particles are then transported to the spraying drum, where water is evenly sprayed onto the surface of the coarse compound fertilizer particles. The spraying pressure is controlled at 0.4 MPa, and the spraying volume is controlled at 6% of the volume of water per ton of coarse compound fertilizer particles. 5. The compound fertilizer granules obtained in step 4 are transported to a dryer for drying, and then cooled and sieved. The sieved fine powder is then transported to a humidifying mixer, and the finished product is transported to a finished product silo for packaging and storage.

[0036] It should be noted that the compound fertilizers produced in Examples 1 to 7 and the comparative examples are a conventional production formula and process in the art. Therefore, the amount of raw materials and process parameters are not described in detail. Of course, the present invention can also be used in other compound fertilizer extrusion granulation production processes.

[0037] The compound fertilizer granules produced in Examples 1 to 7 and the comparative example were tested for granulation rate and granule strength. Granulation rate and granule strength are routine testing items for compound fertilizer granules, and their testing methods and procedures will not be detailed here. The test results are as follows: Table 1. Test results of granulation rate and granule strength of compound fertilizer granules. .

[0038] According to the test results in Table 1, the compound fertilizer granules produced in Examples 1 to 7 showed a significant improvement in granulation rate and granule strength compared to those produced in the comparative example. Furthermore, as the spraying volume of the multi-component granulating agent solution increased, the granulation rate and granule strength of the compound fertilizer granules also increased. However, when the spraying volume of the multi-component granulating agent solution exceeded 6% of the coarse compound fertilizer granules per ton, it resulted in an excessive amount of liquid phase in the spraying drum, leading to the formation of large particles or excessively wet materials.

[0039] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A multi-component granulation aid for extruded compound fertilizer production, characterized in that, It contains the following components by weight percentage: polyvinyl alcohol 12-16%, isocyanate 4-8%, filler 54-72%, magnesium sulfate heptahydrate 2-4%, and starch 10-18%.

2. The multi-component granulation aid for extruded compound fertilizer production as described in claim 1, characterized in that, The polyvinyl alcohol includes one or both of polyvinyl alcohol PVA2488 and PVA1788.

3. The multi-component granulation aid for extruded compound fertilizer production as described in claim 1, characterized in that, The filler includes one or both of titanium dioxide and sodium sulfate.

4. The multi-component granulation aid for extruded compound fertilizer production as described in claim 1, characterized in that, The starch includes one or both of corn starch and tapioca starch.

5. The method for preparing the multi-component granulation aid for extruded compound fertilizer production as described in any one of claims 1 to 4, characterized in that, The following components by mass percentage are added to a mixer and mixed for 1 to 3 hours: 12-16% polyvinyl alcohol, 4-8% isocyanate, 54-72% filler, 2-4% magnesium sulfate heptahydrate, and 10-18% starch. The mixture is then sieved through a 100-300 mesh filter to obtain the multi-component granulation agent.

6. The method of using the multi-component granulation aid for extrusion compound fertilizer production as described in any one of claims 1 to 4, characterized in that, include: (1) Dilution and preparation: Add the multi-component granulation agent and solvent to a mixer at a mass ratio of 1:30 to 1:60 and stir at room temperature for 0.5 to 2 hours to obtain a multi-component granulation agent solution; (2) Spraying operation: The multi-component granulation agent solution is evenly sprayed onto the surface of the compound fertilizer coarse particles through the spraying roller. The spraying pressure is controlled at 0.2-0.4 MPa, and the spraying amount of multi-component granulation agent solution per ton of compound fertilizer coarse particles is controlled at 1-6%.

7. The method of using the multi-component granulation aid for extruded compound fertilizer production as described in claim 6, characterized in that, The solvent is water, and the mass ratio of the multi-component aggregator to the solvent is 1:30 to 1:

40.

8. The method of using the multi-component granulation aid for extruded compound fertilizer production as described in claim 6, characterized in that, The spraying volume of the multi-component agglomerating agent solution per ton of compound fertilizer coarse particles should be controlled at 3-6%.