A process for the production of fertilizers with a polishing step

Abstract

The application relates to the technical field of chemical fertilizer preparation, in particular to a chemical fertilizer preparation process with a polishing process, which comprises the following steps: S1, batching; S2, mixing and stirring; S3, extruding and granulating; S4, crushing and screening; S5, polishing and fine screening; S6, coating treatment; and S7, bagging. The application has the effects of reducing transportation loss and improving product quality.

Description

Technical Field

[0001] This application relates to the field of fertilizer preparation technology, and in particular to a fertilizer preparation process with a polishing step. Background Technology

[0002] Chemical fertilizer is short for chemical fertilizer, which specifically refers to fertilizer made by chemical methods that can meet the nutritional needs of crops. The basic process of chemical fertilizer manufacturing usually includes: mixing the raw materials in proportion by a mixer, extruding the mixture into shape by an extruder, crushing and granulating the extruded material by a crusher, screening the granules by a screening machine, and packaging the granules into bags according to the particle size by a packaging machine.

[0003] In the existing fertilizer manufacturing process, the target particles obtained after crushing and screening the sheet or strip material produced by the extruder have an irregular polyhedral structure. The particle surface and corners have a large number of sharp micro protrusions and macro edges. When these particles with obvious edges are sent to the packaging machine for packaging, they will continuously collide and wear with each other during transportation. The collision and wear between particles will generate a large amount of fine dust (commonly referred to in the industry as "dusting"). Fine dust is easily lost during transportation and seriously affects the quality of product sales, which is a shortcoming. Summary of the Invention

[0004] In order to reduce the problem of a large amount of dust generated by collision and wear between particles during transportation, this application provides a fertilizer preparation process with a polishing step.

[0005] The fertilizer preparation process with a polishing step provided in this application adopts the following technical solution: A fertilizer preparation process with a polishing step includes the following steps: S1, ingredient mixing; S2, mixing and stirring; S3, extrusion and granulation; S4, crushing and screening; S5, polishing and fine screening; S6, coating treatment; S7, packaging.

[0006] Optionally, S1 includes the following steps: S11, quantitatively removing material from the storage tank according to the material composition ratio; S12, the primary belt conveyor transporting the removed material to the primary bucket elevator.

[0007] Optionally, S2 includes the following steps: S21, a mixing machine mixes the material from the primary bucket elevator; S22, a secondary belt conveyor transports a portion of the mixed material to the extruder; S23, another portion of the mixed material on the secondary belt conveyor is transported to the secondary bucket elevator via a pipeline; S24, the secondary bucket elevator transports the material to the return tank; S25, the secondary belt conveyor re-transports the material in the return tank back to the primary belt conveyor.

[0008] Optionally, S3 includes the following steps: S31, the extruder extrudes the material; S32, the pre-crusher performs preliminary crushing of the extruded material to produce initial particles; S33, the three-stage belt conveyor transports the crushed material to the two-stage bucket elevator; S34, the two-stage bucket elevator transports the preliminary crushed material to the first-stage crusher.

[0009] By adopting the above technical solution, the primary belt conveyor transports the material in the storage tank to the primary bucket elevator according to the proportion. The primary bucket elevator then transports the material to the mixing machine. The secondary belt conveyor transports the mixed material to the extruder. Under the extrusion action of the extruder, the loose material is compressed into large-volume solid material. The pre-crusher pre-crushes the large-volume solid material into small-volume granular material. After further crushing and screening, the small-volume granular material is polished by the polishing equipment. Then, the coating equipment covers the surface of the polished granules with a film, and finally, the granules are packaged. Because the sharp edges of the granules become rounded and smooth after polishing, the contact mode between the granules changes from point contact to arc surface contact during transportation. The collision and friction during transportation and storage are significantly reduced, greatly reducing transportation losses and product pulverization rate.

[0010] Optionally, S4 includes the following steps: S41, a fourth-stage belt conveyor transports the material crushed by the first-stage crusher to a third-stage bucket elevator; S42, the third-stage bucket elevator transports the crushed material to a coarse screen; S431, a fifth-stage belt conveyor transports the upper layer of granular material from the coarse screen to a second-stage crusher; S432, a sixth-stage belt conveyor transports the material crushed by the second-stage crusher to a third-stage belt conveyor; S44, a seventh-stage belt conveyor transports the lower layer of granular material from the coarse screen to a fourth-stage bucket elevator; S45, the fourth-stage bucket elevator transports the coarse-screened material to a fine screen; S46, the lower layer of material from the fine screen is re-transported to a secondary bucket elevator via a pipeline; S47, the upper layer of material from the fine screen is transported to a polishing machine.

[0011] By adopting the above technical solution, the combined action of the primary crusher and the secondary crusher can convert large-volume materials into small-particle materials as much as possible, thereby improving the conversion efficiency of qualified materials.

[0012] Optionally, S5 includes the following steps: S51, a polishing machine polishes the granular material after fine screening; S52, an eight-stage belt conveyor transports the polished material to a five-stage bucket elevator; S53, the five-stage bucket elevator transports the polished material to a fine screening machine; S54, the lower layer of material from the fine screening machine is transported to a secondary bucket elevator through a pipeline; S55, the upper layer of material from the fine screening machine is transported to a coating machine.

[0013] By adopting the above technical solution, under the action of the polishing machine, the sharp edges and corners of the granular material after fine screening will tend to be rounded and smooth. Then, the fine screening machine will finely screen the polished granules. Due to the fact that some granules are smaller than the design requirements during the polishing process, they will fall to the lower layer of the fine screening machine. The granules that meet the requirements are left on the upper layer of the fine screening machine, while the granules that do not meet the requirements will be returned to the secondary bucket elevator and re-enter the cycle, which greatly improves the utilization rate of materials.

[0014] Optionally, S6 includes the following steps: S61, the coating machine uniformly coats the coating agent onto the surface of the finely screened particles; S62, the heating and drying equipment on the coating machine dries the coated particles; S63, the coating machine conveys the dried particles to a six-stage bucket elevator; S64, the six-stage bucket elevator conveys the particles to a bagging machine.

[0015] Optionally, S7 includes the following steps: S71, the bagging machine weighs and packages the qualified granular material into bags; S72, the palletizer stacks the bagged material.

[0016] By adopting the above technical solution, the coating machine can evenly coat the coating agent onto the surface of the particles because the polished particles have a smooth and rounded surface. By coating the particle surface with the coating agent, the nutrient release rate of the fertilizer particles can be effectively controlled. Moreover, the particles coated with the coating agent can effectively reduce the loss caused by collision and friction during transportation. At the same time, after the particle edges are blunted, the wear and blockage of the conveying equipment wall and the coating machine nozzle are significantly reduced, greatly extending the equipment maintenance cycle and improving the continuous operation rate and production efficiency of the production line.

[0017] In summary, this application includes at least one of the following beneficial technical effects: The primary belt conveyor transports the material from the storage tank to the primary bucket elevator according to the proportion. The primary bucket elevator then transports the material to the mixing machine. The secondary belt conveyor transports the mixed material to the extruder. Under the extrusion action, the loose material is compressed into large-volume solid material. The pre-crusher pre-crushes the large-volume solid material into small-volume granules. After further crushing and screening, the small-volume granules are polished by the polishing equipment. Then, the coating equipment covers the surface of the polished granules with a film, and finally, they are packaged. Because the sharp edges of the granules become rounded and smooth after polishing, the contact between the granules changes from point contact to arc surface contact during transportation. The collision and friction during transportation and storage are significantly reduced, greatly reducing transportation losses and product pulverization rate. Under the action of the polishing machine, the sharp edges and corners of the granular material after fine screening will tend to be rounded and smooth. Then the fine screening machine will finely screen the polished granules. Because some granules are smaller than the design requirements during the polishing process, they will fall to the lower layer of the fine screening machine. The granules that meet the requirements are left on the upper layer of the fine screening machine, while the granules that do not meet the requirements will be returned to the secondary bucket elevator and re-enter the cycle, which greatly improves the utilization rate of materials and meets the requirements of green and clean production. Because the polished granules have a smooth and rounded surface, the coating machine can evenly coat the coating agent onto the granules. By coating the granules with the coating agent, the nutrient release rate of the fertilizer granules can be effectively controlled. Furthermore, the coating agent can effectively reduce the loss caused by collisions and friction during transportation. At the same time, after the granules' edges are blunted, the wear and clogging of the conveyor wall and the coating machine nozzle are significantly reduced, greatly extending the equipment maintenance cycle and improving the continuous operation rate and production efficiency of the production line. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of an embodiment of this application.

[0019] Figure 2 This is a structural schematic diagram illustrating the pre-crusher in the embodiments of this application.

[0020] Figure 3 This is a cross-sectional view used in the embodiments of this application to illustrate the positional relationship between the static crushing seat, the dynamic crushing seat, and the distance control cylinder.

[0021] Figure 4 This is a cross-sectional view used in the embodiments of this application to illustrate the positional relationship between the guide post, the connecting block, and the leak-proof insert plate.

[0022] Figure 5 This is a cross-sectional view used in the embodiments of this application to illustrate the positional relationship between the static crushing seat, the dynamic crushing seat, and the leak-proof insert plate.

[0023] Explanation of reference numerals in the attached drawings: 1. Chassis; 2. Feed inlet; 3. Discharge outlet; 4. Static crushing seat; 5. Dynamic crushing seat; 6. Distance control cylinder; 7. Crushing shaft; 8. Horizontal groove; 9. Main crushing tooth; 10. Secondary crushing tooth; 11. Receiving groove; 12. Drive assembly; 1201. Leak-proof insert plate; 1202. Sealing inclined surface; 1203. Abutment inclined surface; 1204. Connecting block; 1205. Clearance groove; 1206. Guide post; 1207. Tension block; 1208. Compression spring; 1209. Tension wheel; 1210. Sprocket; 1211. Chain; 1212. Drive motor; 1213. Pulley; 1214. Belt. Detailed Implementation

[0024] The following is in conjunction with the appendix Figures 1-5This application will be described in further detail.

[0025] This application discloses a fertilizer preparation process that includes a polishing step.

[0026] Reference Figure 1 A fertilizer preparation process including a polishing step includes the following steps: S1, Ingredients According to the fertilizer composition ratio, the material in the storage tank is quantitatively removed by intelligent weighing equipment, and the removed material is transported to the first-stage bucket elevator by a first-stage belt conveyor.

[0027] S2, Mixing and Stirring The primary bucket elevator conveys the material to the mixing machine, where it is mixed. The secondary belt conveyor transports a portion of the mixed material to the extruder, while the remaining portion is transported via pipeline to the secondary bucket elevator. The secondary bucket elevator then transports the mixed material to a return tank for temporary storage. Simultaneously, the secondary belt conveyor can transfer the mixed material from the return tank back to the primary belt conveyor, thus ensuring the normal operation of the extruder and reducing the problem of material accumulation after mixing.

[0028] S3, Extrusion and Granulation The extrusion machine compresses the mixture from the secondary belt conveyor, which solidifies the mixture into a large volume of material. The pre-crushing machine then performs preliminary crushing on the solidified material to form initial granular material. Subsequently, the tertiary belt conveyor transports the pre-crushed material to the secondary bucket elevator, which then transports the pre-crushed material to the primary crusher.

[0029] S4. Crushing and Screening The primary crusher further crushes the initially crushed material. The fourth-stage belt conveyor transports the material crushed by the primary crusher to the third-stage bucket elevator. The third-stage bucket elevator then transports the crushed material to the coarse screen. Larger materials on the upper layer of the coarse screen are transported by the fifth-stage belt conveyor to the second-stage crusher, which crushes the larger materials. Finally, the sixth-stage belt conveyor transports the material crushed by the second-stage crusher to the third-stage belt conveyor.

[0030] The smaller materials at the bottom of the coarse screen are conveyed by a seven-stage belt conveyor to a four-stage bucket elevator. The four-stage bucket elevator then conveys the qualified materials from the coarse screen to the fine screen. The smaller materials at the bottom of the fine screen are then transported back to the secondary bucket elevator via pipeline. The qualified materials at the top of the fine screen are then conveyed to the polishing machine.

[0031] The pre-crusher, primary crusher, and secondary crusher have the same structure.

[0032] Reference Figure 2 and Figure 3 The pre-crusher includes a casing 1, with a feed inlet 2 welded to the top of the casing 1 and a discharge outlet 3 opened at the bottom of the casing 1. A static crushing seat 4 is bolted to the casing 1, and a moving crushing seat 5 is horizontally slidably arranged on the casing 1. A distance control cylinder 6, which is electrically connected to the control system, is bolted to the casing 1, and the moving crushing seat 5 is bolted to the piston rod of the distance control cylinder 6.

[0033] Reference Figure 2 and Figure 3 Both the static crushing seat 4 and the moving crushing seat 5 are rotatably connected to a crushing shaft 7. The crushing shaft 7 rotates through the side wall of the housing 1. The housing 1 has a horizontal groove 8 for the crushing shaft 7 on the moving crushing seat 5 to slide. Multiple main crushing teeth 9 and multiple secondary crushing teeth 10 are coaxially sleeved on the crushing shaft 7. The main crushing teeth 9 and the secondary crushing teeth 10 are arranged alternately along the axis of the crushing shaft 7. The main crushing teeth 9 on the static crushing seat 4 correspond one-to-one with the secondary crushing teeth 10 on the moving crushing seat 5.

[0034] Reference Figure 2 and Figure 3 Both the static crushing seat 4 and the dynamic crushing seat 5 are provided with receiving grooves 11. The tooth tip sidewalls of the main crushing tooth 9 and the tooth tip sidewalls of the secondary crushing tooth 10 are in contact with the sidewalls of the receiving grooves 11. The machine housing 1 is provided with a drive assembly 12 that drives the two crushing shafts 7 to rotate synchronously.

[0035] Reference Figure 3 , Figure 4 and Figure 5 The drive assembly 12 includes a leak-proof insert plate 1201 that is vertically slidably connected to the housing 1. A sealing slope 1202 is provided on the bottom side of the leak-proof insert plate 1201 near the moving crushing seat 5. An abutting slope 1203 is provided on the moving crushing seat 5 that abuts against and slides with the sealing slope 1202 on the leak-proof insert plate 1201. A connecting block 1204 is welded on the leak-proof insert plate 1201. An avoidance groove 1205 is provided on the housing 1 for the connecting block 1204 to slide.

[0036] Reference Figure 2 , Figure 3 and Figure 4 During the vertical sliding process, the anti-leakage plate 1201 always blocks the clearance groove 1205. The clearance groove 1205 is located between the two crushing shafts 7. A guide post 1206 is welded inside the clearance groove 1205 of the housing 1. A tension block 1207 is slidably sleeved on the guide post 1206. The tension block 1207 is located directly above the connecting block 1204. A compression spring 1208 supports the connecting block 1204 and the tension block 1207. A tension wheel 1209 is rotatably connected to the tension block 1207.

[0037] Reference Figure 2 , Figure 3 and Figure 4Both crushing shafts 7 are bolted with sprockets 1210. A chain 1211 is wound around both sprockets 1210 and tension wheel 1209. A drive motor 1212 electrically connected to the control system is arranged next to the machine housing 1. Pulleys 1213 are bolted to the output shaft of the drive motor 1212 and the crushing shaft 7 on the stationary crushing seat 4. A belt 1214 is wound around both pulleys 1213.

[0038] According to the different crushing efficiencies required for material particles at different processes, when the control system starts the distance control cylinder 6, the piston rod of the distance control cylinder 6 retracts, thereby moving the moving crushing seat 5 away from the stationary crushing seat 4. During this process, the two crushing shafts 7 move away from each other, and the chain 1211 drives the tension wheel 1209 to descend. The tension wheel 1209 drives the tension block 1207 to approach the connecting block 1204, the compression spring 1208 is compressed, and the connecting block 1204 descends.

[0039] The connecting block 1204 drives the anti-leakage plate 1201 to descend, so that the sealing slope 1202 on the anti-leakage plate 1201 always abuts against and slides with the abutting slope 1203 on the moving crusher seat 5, thereby preventing material from falling from the anti-leakage plate 1201.

[0040] When the control system activates the distance control cylinder 6, the piston rod of the distance control cylinder 6 extends, thereby bringing the moving crushing seat 5 closer to the stationary crushing seat 4. During this process, the abutting inclined surface 1203 on the moving crushing seat 5 abuts against the sealing inclined surface 1202 on the anti-leakage insert plate 1201, causing the anti-leakage insert plate 1201 to rise. The anti-leakage insert plate 1201 drives the connecting block 1204 to rise synchronously and approach the tension block 1207. The compression spring 1208 is compressed, and the tension block 1207 drives the tension wheel 1209 to rise, and the chain 1211 is tensioned, thereby ensuring the stability of the chain 1211 transmission.

[0041] As the main crushing tooth 9 and the secondary crushing tooth 10 rotate with the crushing shaft 7, the tooth tip sidewalls of the main crushing tooth 9 and the secondary crushing tooth 10 are always in contact with the sidewall of the receiving groove 11. Therefore, the crushing size of the material particles is completely controlled by the distance between the main crushing tooth 9 on the moving crushing seat 5 and the secondary crushing tooth 10 on the stationary crushing seat 4, or the distance between the secondary crushing tooth 10 on the moving crushing seat 5 and the main crushing tooth 9 on the stationary crushing seat 4.

[0042] Workers can precisely control the size of crushed material particles simply by adjusting the distance between the two crushing shafts 7, which helps improve the consistency of crushed material particle size and increases the efficiency of converting material particle size to the designed size.

[0043] S5, Polishing and Fine Screening The polishing machine polishes the qualified granular materials through the fine screening, making the sharp edges of the granular materials tend to be rounded and smooth. At this time, the volume of the granular materials will be further reduced. The eight-stage belt conveyor transports the polished material to the five-stage bucket elevator, which then transports the polished material to the fine screening machine. Some of the material particles with reduced volume will fall to the lower layer of the fine screening machine. The material in the lower layer of the fine screening machine will be transported back to the secondary bucket elevator through pipelines, while the material in the upper layer of the fine screening machine will be transported to the coating machine.

[0044] S6. Coating treatment The coating machine will evenly coat the coating agent onto the surface of the finely screened particles. The coating agent will evenly and completely coat the surface of the particles. Then, the heating and drying equipment built into the coating machine will dry the coating agent on the surface of the particles.

[0045] The screening device built into the coating machine will screen the material particles again. The material particles that fail the screening will be returned to the secondary bucket elevator through the pipeline. The material particles that pass the screening will be conveyed to the sixth-stage bucket elevator, which will then convey the granular material to the bagging machine.

[0046] When compound fertilizer needs to be produced, other fertilizers with different components can be added to the six-stage bucket elevator through intelligent weighing equipment.

[0047] S7, Packaging and Packaging The bagging machine weighs and packages qualified granular materials into bags, while the palletizing machine stacks the bagged materials.

[0048] The implementation principle of a fertilizer preparation process with a polishing step in this application embodiment is as follows: by polishing and shaping the fertilizer granules after extrusion granulation, the sharp edges on the surface of the granules are effectively removed, making the surface of the granules more rounded and smooth. After polishing, the contact mode between the granules changes from the original point contact to arc surface contact, and the collision and friction during transportation and storage are significantly reduced. The fine powder rate is reduced from 3%~5% in the traditional process to less than 1%, which greatly reduces transportation loss and product powdering rate.

[0049] After the edges and corners of fertilizer granules are blunted, the wear and blockage of the conveying equipment walls and coating machine nozzles are significantly reduced, extending the equipment maintenance cycle and improving the continuous operation rate and production efficiency of the production line. In terms of material utilization, unqualified materials are returned to the extruder for regranulation through multiple return channels, achieving full utilization of materials and no waste discharge, which meets the requirements of green and clean production.

[0050] Furthermore, in the subsequent coating process, the coating agent can be applied evenly, significantly improving the integrity and density of the coating layer, and effectively improving the nutrient release performance of the controlled-release fertilizer.

[0051] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A fertilizer preparation process including a polishing step, characterized in that, The process includes the following steps: S1, ingredient preparation; S2, mixing and stirring; S3, extrusion and granulation; S4, crushing and screening; S5, polishing and fine screening; S6, coating treatment; S7, packaging.

2. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S1 includes the following steps: S11, quantitatively removing materials from the storage tank according to the material composition ratio; S12, the primary belt conveyor transporting the removed materials to the primary bucket elevator.

3. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S2 includes the following steps: S21, a mixing machine mixes the material from the primary bucket elevator; S22, a secondary belt conveyor transports a portion of the mixed material to the extruder; S23, another portion of the mixed material on the secondary belt conveyor is transported to the secondary bucket elevator via a pipeline; S24, the secondary bucket elevator transports the material to the return tank; S25, the secondary belt conveyor re-transports the material in the return tank back to the primary belt conveyor.

4. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S3 includes the following steps: S31, the extruder extrudes the material; S32, the pre-crusher performs preliminary crushing of the extruded material to produce initial particles; S33, the three-stage belt conveyor transports the crushed material to the two-stage bucket elevator; S34, the two-stage bucket elevator transports the preliminary crushed material to the first-stage crusher.

5. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S4 includes the following steps: S41, a fourth-stage belt conveyor transports the material crushed by the first-stage crusher to a third-stage bucket elevator; S42, the third-stage bucket elevator transports the crushed material to a coarse screen; S431, a fifth-stage belt conveyor transports the upper layer of granular material from the coarse screen to a second-stage crusher; S432, a sixth-stage belt conveyor transports the material crushed by the second-stage crusher to a third-stage belt conveyor; S44, a seventh-stage belt conveyor transports the lower layer of granular material from the coarse screen to a fourth-stage bucket elevator; S45, the fourth-stage bucket elevator transports the coarse-screened material to a fine screen; S46, the lower layer of material from the fine screen is re-transported to a secondary bucket elevator via a pipeline; S47, the upper layer of material from the fine screen is transported to a polishing machine.

6. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S5 includes the following steps: S51, the polishing machine polishes the granular material after fine screening; S52, the eight-stage belt conveyor transports the polished material to the five-stage bucket elevator; S53, the five-stage bucket elevator transports the polished material to the fine screening machine; S54, the lower layer of the fine screening machine is transported to the secondary bucket elevator through a pipeline; S55, the upper layer of the fine screening machine is transported to the coating machine.

7. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S6 includes the following steps: S61, the coating machine uniformly coats the coating agent onto the surface of the finely screened particles; S62, the heating and drying equipment on the coating machine dries the coated particles; S63, the coating machine conveys the dried particles to a six-stage bucket elevator; S64, the six-stage bucket elevator conveys the particles to a bagging machine.

8. The fertilizer preparation process with a polishing step according to claim 1, characterized in that, S7 includes the following steps: S71, the bagging machine weighs and packages the qualified granular materials into bags; S72, the palletizing machine stacks the bagged materials.

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