Processing method and device for urea-formaldehyde slow-release compound fertilizer

Abstract

The present invention belongs to the technical field of compound fertilizer production, and specifically relates to a processing method and device for urea-formaldehyde slow-release compound fertilizer. S1: Put urea and formaldehyde solution into a reaction kettle for mixing and dissolving, set the reaction temperature at 35-65 °C, adjust the pH to 8-9, and carry out a constant-temperature reaction for 0.5-1 h to obtain a urea-formaldehyde prepolymer solution. S2: Mix and pulverize superphosphate, urea phosphate, montmorillonite, borax, potassium chloride, seaweed extract, and mineral source fulvic acid potassium, and obtain a fertilizer matrix after sieving. S3: Add the fertilizer matrix to the movable disk of a disk granulator, and continuously spray the urea-formaldehyde prepolymer solution into the movable disk in an atomized form to carry out fertilizer granulation. Through the decomposition and release by soil microorganisms, the combination of quick-acting, medium-acting, and long-acting nutrients is realized, the fertilizer utilization rate is high, it more conforms to the fertilizer requirement law of crops, the amount or frequency of fertilizer use can be appropriately reduced, and problems such as water eutrophication caused by nutrient loss can be reduced. The particles are uniform, suitable for mechanized fertilization, saving labor and effort.

Description

Technical Field

[0001] The present invention belongs to the technical field of compound fertilizer production, and specifically relates to a processing method and device for urea-formaldehyde slow-release compound fertilizer. Background Art

[0002] Compound fertilizer is a fertilizer containing two or more nutrient elements, usually including nitrogen (N), phosphorus (P), and potassium (K), which are mixed together to provide comprehensive nutrients required by plants, helping to increase crop yield and quality, and simplifying the fertilization process. When using it, a suitable formula should be selected according to the specific needs of the soil and crops.

[0003] A patent of Chinese Patent Application CN103467167B discloses an organic compound fertilizer and its preparation method. The key points of its technical solution are: made from the following raw materials in parts by weight: potassium humate 25 - 30, weathered coal 20 - 24, peat 12 - 16, nano-carbon 1 - 2, soybean dregs 130 - 135, brown sugar 2 - 3, bamboo charcoal powder 12 - 15, medical stone 15 - 18, zeolite 6 - 8, urea 17 - 19, sodium selenite 3 - 4, ferrous sulfate 7 - 9, manganese sulfate 3 - 4, zinc sulfate 2 - 3, soil conditioner 13 - 16, EM bacterial agent 1 - 2; this technology ferments potassium humate, weathered coal, peat, nano-carbon, soybean dregs, brown sugar, bamboo charcoal powder, etc. At the same time, it is combined with a large amount of fertilizers such as urea and trace elements such as sodium selenite to meet the needs of different growth periods of crops, reduce the number of fertilizations, improve soil quality, and improve the quality of crops.

[0004] However, the above technologies often have the following defects: Currently, in order to pursue short-term crop growth efficiency in agricultural planting, an excessive amount of chemical fertilizers is applied at one time during fertilization, resulting in excessive nutrient supply to the soil. As a result, problems such as soil acidification, salinization, and hardening are likely to occur in the planted soil, which will lead to poor crop growth, affect root development, uneven emergence, and excessive growth.

[0005] Therefore, the present invention provides a processing method and device for urea-formaldehyde slow-release compound fertilizer. Summary of the Invention

[0006] In order to make up for the deficiencies of the prior art and solve at least one of the technical problems proposed in the background art.

[0007] The technical solution adopted by the present invention to solve its technical problems is: A processing method for a urea-formaldehyde slow-release compound fertilizer according to the present invention includes the following steps:

[0008] S1: Put urea and formaldehyde solution into a reaction kettle for mixing and dissolving, set the reaction temperature at 35 - 65 °C, adjust the pH to 8 - 9, and react at a constant temperature for 0.5 - 1 h to obtain a urea-formaldehyde prepolymer solution;

[0009] S2: Mix superphosphate, urea phosphate, montmorillonite, borax, potassium chloride, seaweed extract, and potassium fulvate from mineral sources, and put them into a crusher for crushing. After sieving, a fertilizer matrix is obtained.

[0010] S3: Add the fertilizer matrix to the movable plate of a disk granulator, and continuously spray the urea formaldehyde prepolymer solution in an atomized form into the movable plate. Control the rotation of the movable plate through a motor to carry out fertilizer granulation.

[0011] S4: During the rotation of the movable plate, the powdery fertilizer moves through the sieve plate and always remains at the bottom of the movable plate. When the fertilizer gradually forms into spherical granules and the granules are larger than the pore diameter of the sieve plate, the sieve plate will lift the fertilizer granules upward.

[0012] S5: The pressure roller intermittently rolls on the surface of the arc-shaped block outside the fixed plate, driving the slider to slide inside the chute, prompting the sieve plate to continuously reciprocate, and driving the formed granules on its surface to vibrate, screening out the powdery fertilizer entrained between the formed granules.

[0013] S6: When the sieve plate passes through the top of the movable plate, the granules on the surface of the sieve plate fall into the fixed plate through the collection port, and are discharged outward through the discharge port and the discharge channel. After drying, the urea formaldehyde slow-release compound fertilizer is obtained.

[0014] A processing device for urea formaldehyde slow-release compound fertilizer, which is applied to the processing method of the above-mentioned urea formaldehyde slow-release compound fertilizer. The disk granulator described in step S3 includes a frame; a fixed plate is fixedly connected to the top of the frame; a movable plate is rotatably connected to the outside of the fixed plate; both the fixed plate and the movable plate are designed to be in an inclined state; a toothed ring is fixedly connected to the back of the movable plate; a motor is fixedly connected to the back of the fixed plate; a gear is connected to the output shaft of the motor, and the gear meshes with the toothed ring; a group of sieve plates are evenly distributed inside the movable plate; a collection port is arranged on the top of the fixed plate; a discharge port is arranged at the bottom of the fixed plate; a discharge channel is fixedly connected to the back of the fixed plate, and the discharge channel is communicated with the discharge port.

[0015] Preferably, a group of chutes are evenly distributed on the side surface of the movable plate; a slider is slidably connected inside the chute; one side of the slider is fixedly connected to the sieve plate, and a first spring is fixedly connected between the other side of the slider and the chute; a pressure roller is rotatably connected to the side of the sieve plate away from the slider, and the pressure roller is in contact with the outside of the fixed plate; a group of arc-shaped blocks are evenly distributed on the outside of the fixed plate.

[0016] Preferably, a pair of ear plates are fixedly connected to the surface of the slider; the sieve plate is inserted between the pair of ear plates, and the sieve plate is fixedly connected to the ear plates through bolts.

[0017] Preferably, a group of scraping blades are evenly distributed on the surface of the sieve plate, and the scraping blades are in contact with the movable plate.

[0018] Preferably, an installation ring is fixedly connected inside the fixed disk; an outer ring member is fixedly connected to the inner side of the fixed disk; an inner ring member is fixedly connected to the outer side of the installation ring; an annular material guiding groove is formed between the outer ring member and the inner ring member; the material guiding groove is designed in a wavy shape; electric heating sheets are arranged inside both the outer ring member and the inner ring member.

[0019] Preferably, a slag removal port is arranged at the position corresponding to the discharge port at the bottom of the fixed disk; a slag removal net is fixedly connected inside the slag removal port; an arc-shaped plate is arranged at the position corresponding to the collection port at the top of the inner ring member; a second spring is fixedly connected between the arc-shaped plate and the inner ring member.

[0020] Preferably, the arc-shaped block is made of an elastic material; a closed cavity is formed inside the arc-shaped block and an elastic member is fixedly connected thereto; the arc-shaped block is communicated with a conduit, and the other end of the conduit penetrates through the outer ring member and is communicated with the material guiding groove.

[0021] Preferably, a group of elastic wires are fixedly connected to the surface of the outer ring member at the position corresponding to the conduit.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. For the processing method and device of the urea-formaldehyde slow-release compound fertilizer of the present invention, aiming at problems such as soil acidification, salinization, and hardening, seaweed extract and mineral source fulvic acid potassium are integrated, which contain a variety of functional groups, are beneficial to the formation of soil aggregate structure, improve the soil, can adsorb heavy metal ions and salt ions in the soil, and relieve the poor growth of crop roots caused by soil salinization; contain natural growth regulating substances, which can regulate the growth of crops; contain rich mineral nutrients such as potassium, calcium, and magnesium, etc., can activate the solidified mineral nutrients in the soil, supplement a variety of essential nutrient elements and beneficial elements for crops, are beneficial to the strong growth of crops, and improve the quality; the alkaline groups and acidic groups therein can adsorb free H+ and OH- in the soil, and relieve the poor growth problems of crops caused by soil acidification or salinization.

[0024] 2. For the processing method and device of the urea-formaldehyde slow-release compound fertilizer of the present invention, when granulating the fertilizer, when the fertilizer particles reach a certain size, they can be automatically screened out and discharged, without the need for manual shoveling of the finished particles, overcoming the problem of inconvenient discharging of the disk granulator in the prior art, and this device can discharge while granulating. When the powdery fertilizer in the movable disk gradually decreases, new fertilizer can be added to its interior. Therefore, the granulator does not need to stop during the feeding and discharging processes, realizing continuous granulation production and improving the production efficiency of the urea-formaldehyde slow-release compound fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 It is a schematic flow chart of the method of the present invention;

[0027] Figure 2 It is a schematic structural diagram of the disk granulator in the present invention;

[0028] Figure 3 It is a schematic structural diagram of the disk granulator from another perspective in the present invention;

[0029] Figure 4 is Figure 3 the partial enlarged view at position A in;

[0030] Figure 5 It is a schematic structural diagram of the sieve plate in the present invention;

[0031] Figure 6 It is the front view of the fixed disk and the movable disk in the present invention;

[0032] Figure 7 is Figure 6 the partial enlarged view at position B in.

[0033] In the figure: frame 1, fixed disk 2, movable disk 3, toothed ring 4, motor 5, gear 6, sieve plate 7, collection port 8, discharge port 9, discharge channel 10, chute 11, slider 12, first spring 13, pressure roller 14, arc block 15, ear plate 16, scraping blade 17, mounting ring 18, outer ring part 19, inner ring part 20, material guiding groove 21, electric heating sheet 22, slag removal net 23, arc plate 24, second spring 25, elastic part 26, conduit 27, elastic wire 28. Specific embodiments

[0034] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0035] As Figure 1 shown, a processing method of an urea-formaldehyde slow-release compound fertilizer according to the present invention includes the following steps:

[0036] S1: Put urea and formaldehyde solution into a reaction kettle for mixing and dissolving, set the reaction temperature to 35 - 65 °C, adjust the pH to 8 - 9, and carry out a constant temperature reaction for 0.5 - 1 h to obtain an urea-formaldehyde prepolymer solution;

[0037] S2: Mix calcium superphosphate, urea phosphate, montmorillonite, borax, potassium chloride, seaweed extract, and mineral source fulvic acid potassium and put them into a pulverizer for pulverization treatment, and obtain a fertilizer matrix after sieving;

[0038] S3: Add the fertilizer matrix into the movable disk 3 of the disk granulator, and continuously spray the urea-formaldehyde prepolymer solution in an atomized form into the movable disk 3, and control the rotation of the movable disk 3 through the motor 5 to carry out fertilizer granulation;

[0039] S4: During the rotation of the movable disk 3, the powdery fertilizer moves through the sieve plate 7 and always remains at the bottom of the movable disk 3. When the fertilizer gradually forms into spherical granules and the granules are larger than the pore diameter of the sieve plate 7, the sieve plate 7 will lift the fertilizer granules upward;

[0040] S5: The pressure roller 14 intermittently rolls on the outer side of the fixed disk 2 to the surface of the arc-shaped block 15, driving the slider 12 to slide inside the chute 11, prompting the sieve plate 7 to continuously reciprocate, and driving the formed granules on its surface to vibrate, screening out the powdery fertilizer entrained between the formed granules;

[0041] S6: When the sieve plate 7 passes over the top of the movable disk 3, the granules on the surface of the sieve plate 7 fall into the interior of the fixed disk 2 through the collection port 8, and are discharged outward through the discharge port 9 and the discharge channel 10. After drying, the urea-formaldehyde slow-release compound fertilizer is obtained.

[0042] The present invention reacts urea with formaldehyde to generate medium- and long-acting nutrients such as 1-methylol-2-urea and 2-methylol-3-urea. After being applied to the soil, it is decomposed and released by soil microorganisms, realizing the combination of quick-acting, medium-acting, and long-acting nutrients. The fertilizer utilization rate is high, which is more in line with the fertilizer requirement law of crops. It can appropriately reduce the amount or frequency of fertilizer application, reduce problems such as water eutrophication caused by nutrient loss. The granules are uniform, suitable for mechanized fertilization, saving labor and effort.

[0043] Aiming at problems such as soil acidification, salinization, and hardening, seaweed extract and mineral source fulvic acid potassium are integrated. It contains a variety of functional groups, which is beneficial to the formation of soil aggregate structure, improves the soil, can adsorb heavy metal ions and salt ions in the soil, and alleviates the poor growth of crop roots caused by soil salinization; it contains natural growth regulating substances, which can regulate crop growth; it contains rich mineral nutrients such as potassium, calcium, and magnesium, which can activate the solidified mineral nutrients in the soil, supplement a variety of essential and beneficial elements for crops, and is beneficial to the strong growth of crops and improving the quality; the basic groups and acidic groups in it can adsorb free H+ and OH- in the soil, alleviating the problems of poor crop growth caused by soil acidification or salinization.

[0044] Such as Figures 2 to 7As shown in the figure, a processing device for a urea-formaldehyde slow-release compound fertilizer according to the present invention is applied to the processing method of the above-mentioned urea-formaldehyde slow-release compound fertilizer. In step S3, the disk granulator includes a frame 1; a fixed disk 2 is fixedly connected to the top of the frame 1; a movable disk 3 is rotatably connected to the outside of the fixed disk 2; both the fixed disk 2 and the movable disk 3 are designed to be in an inclined state; a toothed ring 4 is fixedly connected to the back of the movable disk 3; a motor 5 is fixedly connected to the back of the fixed disk 2; a gear 6 is connected to the output shaft of the motor 5, and the gear 6 meshes with the toothed ring 4; a group of sieve plates 7 are evenly distributed inside the movable disk 3; a collection port 8 is arranged at the top of the fixed disk 2; a discharge port 9 is arranged at the bottom of the fixed disk 2; a discharge channel 10 is fixedly connected to the back of the fixed disk 2, and the discharge channel 10 is communicated with the discharge port 9.

[0045] When this device is in use, the fertilizer matrix is placed inside the movable disk 3 outside the fixed disk 2. The motor 5 is used to control the rotation of the gear 6, and the toothed ring 4 is used to drive the movable disk 3 and the sieve plates 7 to rotate, so that the fertilizer rolls in the movable disk 3. At the same time, the urea-formaldehyde prepolymer solution is continuously sprayed inside the movable disk 3. During the rotation of the movable disk 3, the powdery fertilizer can move through the sieve plates 7 and always be located at the bottom of the movable disk 3. When the fertilizer gradually forms into spherical particles and the particles are larger than the pore diameter of the sieve plates 7, the sieve plates 7 can lift the fertilizer particles upward. When passing through the top of the movable disk 3, the particles on the surface of the sieve plates 7 fall into the inside of the fixed disk 2 through the collection port 8 and are discharged outward through the discharge port 9 and the discharge channel 10.

[0046] When granulating the fertilizer according to the present invention, when the fertilizer particles reach a certain size, they can be automatically screened out and discharged, without manually shoveling out the finished particles, which overcomes the problem of inconvenient discharging of the disk granulator in the prior art. And this device can granulate and discharge at the same time. When the powdery fertilizer in the movable disk 3 gradually decreases, new fertilizer can be added to its inside. Therefore, the granulator does not need to stop during the feeding and discharging processes, realizing continuous granulation production and improving the production efficiency of the urea-formaldehyde slow-release compound fertilizer.

[0047] As a preferred embodiment of the present invention, a group of sliding grooves 11 are evenly distributed on the side of the movable disk 3; a slider 12 is slidably connected inside the sliding grooves 11; one side of the slider 12 is fixedly connected to the sieve plate 7, and a first spring 13 is fixedly connected between the other side of the slider 12 and the sliding grooves 11; a pressure roller 14 is rotatably connected to the side of the sieve plate 7 away from the slider 12, and the pressure roller 14 is in contact with the outside of the fixed disk 2; a group of arc-shaped blocks 15 are evenly distributed on the outside of the fixed disk 2.

[0048] During the rotation of the sieve plate 7 with the movable plate 3, the pressure roller 14 rolls in contact with the outer side of the fixed plate 2, thereby sealing the gap between the sieve plate 7 and the fixed plate 2, preventing the formed particles lifted by the sieve plate 7 from falling downward through this gap, improving the screening efficiency of the finished particles, and the pressure roller 14 intermittently rolls onto the surface of the arc-shaped block 15, driving the slider 12 to slide inside the chute 11 and compressing the first spring 13, thereby promoting the sieve plate 7 to continuously reciprocate in the radial direction of the movable plate 3 and driving the formed particles on its surface to vibrate, so as to screen out the powdered fertilizer entrained between the formed particles, making the powdered fertilizer fall downward to the bottom of the movable plate 3, and the formed fertilizer particles remain on the surface of the sieve plate 7 and are introduced into the collection port 8.

[0049] A pair of ear plates 16 are fixedly connected to the surface of the slider 12; the sieve plate 7 is inserted between the pair of ear plates 16, and the sieve plate 7 is fixedly connected to the ear plates 16 by bolts. The sieve plate 7 is fixed to the slider 12 by bolts, so that it is convenient to replace the sieve plate 7 when it is damaged, and when it is necessary to produce fertilizer particles of different sizes, the sieve plate 7 with different pore diameters can be replaced according to actual needs, improving the practicability of the disk granulator.

[0050] As a preferred embodiment of the present invention, a group of scraping blades 17 are evenly distributed on the surface of the sieve plate 7, and the scraping blades 17 are in contact with the movable plate 3. By arranging the scraping blades 17, during the reciprocating movement of the sieve plate 7, the scraping blades 17 can scrape back and forth on the surface of the movable plate 3, thereby scraping off the materials adhered to its surface, reducing material residue, and improving the forming efficiency of the fertilizer.

[0051] As a preferred embodiment of the present invention, an installation ring 18 is fixedly connected inside the fixed plate 2; an outer ring member 19 is fixedly connected to the inner side of the fixed plate 2; an inner ring member 20 is fixedly connected to the outer side of the installation ring 18; a ring-shaped material guiding groove 21 is formed between the outer ring member 19 and the inner ring member 20; the material guiding groove 21 is designed to be wavy; heating sheets 22 are arranged inside both the outer ring member 19 and the inner ring member 20.

[0052] When the granular fertilizer falls into the fixed plate 2 through the collection port 8, it can enter the inside of the material guiding groove 21 and further roll and form inside the material guiding groove 21, improving the forming quality of the fertilizer. Since the material guiding groove 21 is wavy, the rolling path of the particles can be extended, the forming difficulty can be reduced, and the particles continuously collide with the wavy side walls inside the material guiding groove 21, which can change the movement direction and movement path of the particles, thereby promoting uniform forming of the fertilizer in all directions and improving the roundness of the fertilizer particles. Then the fertilizer is discharged outward through the discharge port 9.

[0053] By arranging the heating sheets 22 to heat the fertilizer particles passing through the inside of the material guiding groove 21, the moisture content inside them can be reduced, and the particle density can be increased.

[0054] As a preferred embodiment of the present invention, a slag removal port is provided at the bottom of the fixed disk 2 corresponding to the discharge port 9; a slag removal net 23 is fixedly connected inside the slag removal port; an arc-shaped plate 24 is provided at the top of the inner ring member 20 corresponding to the collection port 8; a second spring 25 is fixedly connected between the arc-shaped plate 24 and the inner ring member 20. When the fertilizer particles fall into the collection port 8, they fall on the surface of the arc-shaped plate 24, and under the action of the second spring 25, the arc-shaped plate 24 is urged to drive the fertilizer to vibrate repeatedly, so as to shake off the powdery materials adhered to the surface of the particles. Then, the granular fertilizer further rolls and collides inside the material guiding groove 21 to further separate the particles from the powder. Finally, both of them fall on the surface of the slag removal net 23. The granular fertilizer is discharged through the discharge port 9, and the powdery materials pass through the slag removal net 23 and return to the inside of the movable disk 3 to perform secondary granulation, improving the utilization degree of the materials and reducing the slag content rate of the finished fertilizer.

[0055] As a preferred embodiment of the present invention, the arc-shaped block 15 is made of an elastic material; a closed cavity is formed inside the arc-shaped block 15 and an elastic member 26 is fixedly connected thereto; the arc-shaped block 15 is communicated with a conduit 27, and the other end of the conduit 27 penetrates through the outer ring member 19 and is communicated with the material guiding groove 21. When the pressing roller 14 rolls to the surface of the arc-shaped block 15, the air inside the arc-shaped block 15 can be extruded through the conduit 27 and sprayed into the material guiding groove 21 to impact the particles moving inside the material guiding groove 21, and the impact direction is different from the movement path of the particles, further causing the fertilizer particles to roll and form in different directions, reducing the probability of their appearance of irregular shapes, and the impact of the air flow can promote the powdery fertilizer to fall off from the surface of the particles, improving the separation efficiency between the particles and the powder.

[0056] A group of elastic wires 28 are fixedly connected to the surface of the outer ring member 19 corresponding to the conduit 27. By providing the elastic wires 28, when the conduit 27 jets air, the elastic wires 28 can swing under the action of the air flow, so as to use the elastic wires 28 to friction and disturb the particles passing through the material guiding groove 21, further removing the powder adhered to the surface of the particles and improving the purity of the fertilizer.

[0057] The above front, back, left, right, up, and down are all based on the Figure 1 in the accompanying drawings of the specification. Taking the perspective of the observer as the standard, the side of the device facing the observer is defined as the front, and the left side of the observer is defined as the left, and so on.

[0058] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the protection scope of the present invention.

[0059] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the description in the specification are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for processing urea-formaldehyde slow-release compound fertilizer, characterized in that: The following steps are involved: S1: Put urea and formaldehyde solution into a reaction kettle, mix and dissolve, set the reaction temperature to 35-65°C, adjust the pH to 8-9, and react at a constant temperature for 0.5-1h to obtain urea-formaldehyde prepolymer solution; S2: Mixing superphosphate, urea phosphate, montmorillonite, borax, potassium chloride, seaweed extract, and mineral potassium humate, putting the mixture into a grinder for grinding, and sieving to obtain a fertilizer matrix; S3: adding the fertilizer matrix into the movable disk of the disc granulator, and continuously spraying the urea-formaldehyde prepolymer liquid into the movable disk in the form of atomization, and controlling the movable disk to rotate by a motor to perform fertilizer granulation; S4: During the rotation of the movable disk, the powdered fertilizer moves through the sieve plate and is always located at the bottom of the movable disk. When the fertilizer gradually forms into spherical particles, and the particles are larger than the aperture of the sieve plate, the sieve plate will lift the fertilizer particles upwards; S5: The pressing roller intermittently rolls on the outer side of the fixed plate to the surface of the arc block, driving the slider to slide inside the slide groove, causing the screen plate to continuously reciprocate, and driving the formed particles on its surface to shake, so as to screen out the powdered fertilizer entrained between the formed particles; S6: When the sieve plate passes through the top of the movable plate, the particles on the surface of the sieve plate fall into the fixed plate through the collecting port and are discharged outward through the discharge port and the discharge channel. After drying, urea-formaldehyde slow-release compound fertilizer is obtained; The disc granulator in step S3 comprises a frame; a fixed disc is fixedly connected to the top of the frame; a movable disc is rotatably connected to the outer side of the fixed disc; the fixed disc and the movable disc are both designed to be in an inclined state; a gear ring is fixedly connected to the back of the movable disc; a motor is fixedly connected to the back of the fixed disc; a gear is connected to the output shaft of the motor, and the gear is meshed with the gear ring; a group of sieve plates are evenly distributed inside the movable disc; a collecting port is provided at the top of the fixed disc; a discharging port is provided at the bottom of the fixed disc; a discharging channel is fixedly connected to the back of the fixed disc, and the discharging channel is connected to the discharging port; A group of slide grooves are evenly distributed on the side of the movable disk; a slider is slidably connected inside the slide groove; one side of the slider is fixedly connected to the screen plate, and a spring is fixedly connected between the other side and the slide groove; a pressure roller is rotatably connected to the side of the screen plate away from the slider, and the pressure roller is in contact with the outer side of the fixed disk; a group of arc blocks are evenly distributed on the outer side of the fixed disk; The fixing plate is fixedly connected with a mounting ring inside; the fixing plate is fixedly connected with an outer ring inside; the mounting ring is fixedly connected with an inner ring outside; an annular material guide groove is formed between the outer ring and the inner ring; the material guide groove is designed to be wavy; electric heating plates are arranged inside the outer ring and the inner ring; The arc block is made of elastic material; a closed cavity is formed inside the arc block and is fixedly connected with an elastic member; the arc block is connected with a conduit, and the other end of the conduit passes through the outer ring member and is connected with the material guide groove.

2. The method for processing a urea-formaldehyde slow-release compound fertilizer according to claim 1, characterized in that: A pair of ear plates are fixedly connected to the surface of the sliding block; the sieve plate is inserted between the pair of ear plates, and the sieve plate and the ear plates are fixedly connected by bolts.

3. The method for processing a urea-formaldehyde slow-release compound fertilizer according to claim 1, characterized in that: A group of scrapers are evenly distributed on the surface of the sieve plate, and the scrapers are in contact with the movable disk.

4. The method for processing a urea-formaldehyde slow-release compound fertilizer according to claim 1, characterized in that: A slag removal port is provided at the bottom of the fixed plate at a position corresponding to the discharge port; a slag removal net is fixedly connected inside the slag removal port; an arc plate is provided at the top of the inner ring at a position corresponding to the collection port; a second spring is fixedly connected between the arc plate and the inner ring.

5. The method for processing a urea-formaldehyde slow-release compound fertilizer according to claim 1, characterized in that: A group of elastic threads are fixedly connected to the surface of the outer ring at positions corresponding to the catheter.

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