Carbon-based long-acting slow-release fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of fertilizers, in particular to a carbon-based long-acting slow-release fertilizer and a preparation method thereof. The carbon-based long-acting slow-release fertilizer provided by the invention comprises the carbon-based material with the specific surface area of 350 m < 2 > / g-1700 m < 2 > / g, the thermosetting resin and the compound fertilizer, effectively overcomes the problems of fluctuation influence of environment temperature and rainwater leaching and leaching, is balanced in fertility release speed and long in fertilizer efficiency time, and has the effective fertilizer efficiency time of 2-12 months; and sufficient fertility can be stably and continuously provided for plants for a long time. In addition, the invention also provides a preparation method of the carbon-based long-acting slow-release fertilizer, and the method is simple in process operation, low in equipment requirement and excellent in product effect, and has a remarkable application value in industrial production of the carbon-based long-acting slow-release fertilizer.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizers, and in particular to a carbon-based long-acting slow-release fertilizer and a preparation method thereof. Background Art

[0002] In agricultural applications, slow-release fertilizers have the advantages of improving fertilizer utilization, reducing nutrient loss, continuously supplying nutrients, improving soil environment, and saving labor costs. They have good market prospects in the application of flowers and plants, high-end landscape trees, and grain planting.

[0003] However, the slow-release fertilizers currently on the market have the defects of being greatly affected by temperature and easy to leach, which leads to a significant shortening of the release time of the slow-release fertilizer. The release of slow-release fertilizer efficiency increases linearly with the increase of temperature, which is easy to cause fertilizer damage in the high temperature season in summer. Therefore, it is necessary to pay attention to seasonal changes when using slow-release fertilizers. Plants that are dormant or semi-dormant in summer should not use slow-release fertilizers; at the same time, the nutrients of slow-release fertilizers need to be released by soaking in water, which makes them more easily washed away by rainwater and prone to leaching in rainy weather, which not only greatly reduces the effect of the fertilizer, but also may cause the fertilizer to dissolve quickly if used improperly, causing negative effects on plants.

[0004] Chinese patent CN109851435A disclosed a slow-release long-acting compound fertilizer for corn on June 7, 2019, and its preparation method and application. The coating material of the slow-release long-acting compound fertilizer has a specific surface area of ​​about 11.66 m 2 / g of modified coal slag powder, after application test, the modified coal slag coated compound fertilizer can increase the yield by about 9%. However, coal slag is easy to dissolve and migrate under the action of rainwater leaching, and the specific surface area of ​​the modified coal slag powder is still small, and the amount of compound fertilizer that can be loaded and coated is also low. It can be seen that how to overcome the influence of temperature and rainwater leaching and obtain a long-acting slow-release fertilizer is still a problem that technicians in this field need to solve. Summary of the invention

[0005] In order to solve the technical problem of how to overcome the influence of temperature and rainwater leaching and obtain a long-acting slow-release fertilizer, the present invention provides a carbon-based long-acting slow-release fertilizer, the components of which include: carbon-based material, thermosetting resin and compound fertilizer; The carbon-based material is prepared by mixing a thermosetting resin and a curing agent in a weight ratio of 100: (12-18), and has a specific surface area of ​​350 m 2 / g~1700 m 2 / g.

[0006] In one embodiment, the distribution ratio of each group is as follows according to weight parts: 5~10 parts of carbon-based materials Thermosetting resin 6~20 parts 40~90 parts of compound fertilizer.

[0007] In one embodiment, the thermosetting resin is any one of urea-formaldehyde resin, epoxy resin and phenolic resin.

[0008] In one embodiment, the curing agent is 75% p-toluenesulfonic acid.

[0009] In one embodiment, the carbon-based material is prepared according to the following steps: Mix the thermosetting resin and curing agent and stir evenly; Quickly pour into the preheated mold and dry in an oven to obtain a solidified material; crushing the solidified material to obtain solidified particles; The solidified particles are placed in a carbonization furnace for calcination and carbonization to obtain the carbon-based material.

[0010] Furthermore, the mold preheating temperature is 75℃~85℃, the oven drying temperature is 75℃~85℃, and the drying time is 15min~20 min; the calcination carbonization temperature is 700℃~950℃, the heating time is 2h~3h, and the constant temperature time is 2h~8h.

[0011] Furthermore, the particle size of the solidified particles is 2 mm to 3 mm.

[0012] Furthermore, during the constant temperature calcination stage, water vapor is introduced for activation, which can further increase the specific surface area of ​​the carbon-based material.

[0013] The present invention also provides a method for preparing any of the above carbon-based long-acting slow-release fertilizers, comprising the following steps: Melting the compound fertilizer and the thermosetting resin separately for later use; The carbon-based material is put into a granulator, and the melted compound fertilizer and thermosetting resin are put into the sprayer above the granulator respectively; While stirring the carbon-based material, compound fertilizer is sprayed in for fertilizer adsorption; After the carbon-based material has fully absorbed the fertilizer, continue stirring and start spraying thermosetting resin to coat the material with the resin; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the thermosetting resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0014] Furthermore, the stirring speed of the granulator is 35 rpm~45 rpm; the spray rate of the sprayer is 8 L / min~15 L / min.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The carbon-based long-acting slow-release fertilizer provided by the present invention has a balanced fertility release rate and a long fertilizer effect time, effectively overcomes the influence of ambient temperature fluctuations and the problem of rainwater leaching and leaching, and can stably and continuously provide sufficient fertility for plants.

[0016] In addition, the carbon-based material in the carbon-based long-acting slow-release fertilizer component has an optimal specific surface area range and a high adsorption rate for compound fertilizers. In particular, a better carbon-based material product can be obtained with lower energy consumption, has high economic value, and is conducive to industrial and large-scale production and application.

[0017] The present invention also provides a method for preparing a carbon-based long-acting slow-release fertilizer, which has simple process operation, low requirements on equipment and excellent product effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a scanning electron microscope image of the micropore structure of the carbon-based material provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0022] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 15 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 700° C. for 3 h, and then kept at 700° C. for 2 h. The carbon-based material is obtained after calcination and carbonization.

[0023] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0024] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 388.669 m 2 / g, and the adsorption rate of compound fertilizer is 40%.

[0025] Example 2 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0026] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 15 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 800° C. for 3 h, and then kept at 800° C. for 2 h. The carbon-based material is obtained after calcination and carbonization.

[0027] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0028] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 622.230 m 2 / g, and the adsorption rate of compound fertilizer is 60%.

[0029] Example 3 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0030] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 15 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 950° C. for 3 h, and then kept at 950° C. for 2 h. The carbon-based material is obtained after calcination and carbonization.

[0031] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0032] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 950.325 m 2 / g, the adsorption rate of compound fertilizer is 70%; the microporous structure of the carbon-based material is reference Figure 1 shown.

[0033] Example 4 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0034] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 15 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 950° C. for 3 h, and then kept at 950° C. for 8 h. The carbon-based material is obtained after calcination and carbonization.

[0035] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0036] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 1300.988 m 2 / g, and the adsorption rate of compound fertilizer is 80%.

[0037] Example 5 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0038] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 15 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 950°C for 3 hours, and then kept at 950°C for 8 hours. During the constant temperature period, water vapor is continuously introduced at a steam pressure of 0.7 MPa using an electric steam generator for activation. The carbon-based material is obtained after calcination and carbonization.

[0039] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0040] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 1600.000 m 2 / g, and the adsorption rate of compound fertilizer is 88%.

[0041] Example 6 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0042] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 12 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 950° C. for 3 h, and then kept at 950° C. for 2 h. The carbon-based material is obtained after calcination and carbonization.

[0043] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0044] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 920.250 m 2 / g, and the adsorption rate of compound fertilizer is 68%.

[0045] Example 7 This embodiment provides a carbon-based long-acting slow-release fertilizer, which is prepared according to the following steps.

[0046] (1) Preparation of carbon-based materials Mix 100 parts by weight of phenolic resin and 18 parts by weight of 75% p-toluenesulfonic acid, and stir evenly; Quickly pour into a mold preheated to 80°C, and dry in an oven at 80°C for 15 min to obtain a solidified material; The solidified material is crushed to a particle size of 2 mm to 3 mm to obtain solidified particles; The solidified particles are placed in a carbonization furnace, heated to 950° C. for 3 h, and then kept at 950° C. for 2 h. The carbon-based material is obtained after calcination and carbonization.

[0047] (2) Preparation of carbon-based long-acting slow-release fertilizer 100 parts by weight of compound fertilizer and 10 parts by weight of urea-formaldehyde resin are melted separately for later use; 6 parts by weight of carbon-based material are put into a granulator, and the melted compound fertilizer and urea-formaldehyde resin are put into the sprayer above the granulator respectively; The compound fertilizer was sprayed into the carbon-based material while stirring it for fertilizer adsorption, wherein the stirring speed of the granulator was 41 rpm and the spray rate of the sprayer was 10 L / min; After the carbon-based material fully absorbs the fertilizer, continue stirring and spray urea-formaldehyde resin at a spray rate of 10 L / min for resin coating; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the urea-formaldehyde resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

[0048] In this embodiment, it is measured that the specific surface area of ​​the carbon-based material is 968.300 m 2 / g, and the adsorption rate of compound fertilizer is 71.5%.

[0049] The present invention also provides the following comparative example for preparing a carbon-based slow-release fertilizer: Comparative Example 1 The difference between this comparative example and Example 1 of the present invention is that when the solidified particles are calcined and carbonized, the calcination temperature is 650° C. The other raw materials, proportions, operating steps and process parameters are consistent with those of Example 1.

[0050] In this comparative example, it was measured that the specific surface area of ​​the carbon-based material was 3.928 m 2 / g, and the adsorption rate of compound fertilizer is 15%.

[0051] Comparative Example 2 The difference between this comparative example and Example 5 of the present invention is that when the solidified particles are calcined and carbonized, the heating time is 5 hours and the constant temperature time is 10 hours. The other raw materials, proportions, operating steps and process parameters are consistent with those of Example 1.

[0052] In this comparative example, it was measured that the specific surface area of ​​the carbon-based material was 1900.000 m 2 / g, the adsorption rate of compound fertilizer is 100%; but the adsorption granulation time is 3 times that of Example 5 and 4 times that of Example 4.

[0053] Test example The carbon-based long-acting slow-release fertilizers prepared in the above Examples 1 to 7 and the carbon-based slow-release fertilizers prepared in Comparative Examples 1 and 2 were subjected to simulated environmental aging tests according to Section 3.6 of GB / T 23348-2009 "Slow-release Fertilizers" on the nutrient release period. Specifically, the release time of the slow-release nutrients is expressed as the time required for the slow-release nutrients to reach 80% of the cumulative nutrient release rate from the start of extraction in still water at 25°C. The test results are listed in Table 1.

[0054] Table 1 Summary of test results of simulated environmental aging test

[0055] According to Table 1, the carbon-based slow-release fertilizers prepared in Examples 1 to 7 of the present invention have effective time periods of more than 2 months, and can be up to 370 days. The carbon-based slow-release fertilizer prepared in Comparative Example 1 has too low a release amount and cannot provide sufficient fertility for plants. This is because the carbon-based material has a small specific surface area and the effective adsorption amount of fertilizer is low during adsorption granulation. The carbon-based slow-release fertilizer prepared in Comparative Example 2 has the longest effective time period of 390 days, and the adsorption rate of the composite fertilizer is 100%, but its adsorption granulation time and energy cost are greatly increased, and the economic benefits are low.

[0056] In summary, the present invention is designed to prepare a specific surface area of ​​350 m 2 / g~1700 m 2 / g of carbon-based material is used as the adsorption load basis of the compound fertilizer, and then it is wrapped and granulated with thermosetting resin. The obtained carbon-based long-acting slow-release fertilizer can effectively overcome the influence of environmental temperature changes and rain leaching, release fertilizer evenly, and have a long fertilizer effect, and can provide plants with sufficient fertilizer in a stable and continuous manner.

[0057] Although the terminology such as long-acting, super-effective, slow-release fertilizer, compound fertilizer, carbon-based material, calcination carbonization, adsorption, encapsulation, loading, activation, melting, etc. is used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only for the purpose of more conveniently describing and explaining the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon-based long-acting slow-release fertilizer, characterized in that: Its components include: carbon-based materials, thermosetting resins and compound fertilizers; The carbon-based material is prepared by mixing a thermosetting resin and a curing agent in a weight ratio of 100: (12-18), and has a specific surface area of ​​350 m 2 / g~1700 m 2 / g.

2. The carbon-based long-acting slow-release fertilizer according to claim 1, characterized in that: The distribution ratio of each group is as follows: 5~10 parts of carbon-based materials Thermosetting resin 6~20 parts 40~90 parts of compound fertilizer.

3. The carbon-based long-acting slow-release fertilizer according to claim 1, characterized in that: The thermosetting resin is any one of urea-formaldehyde resin, epoxy resin and phenolic resin.

4. The carbon-based long-acting slow-release fertilizer according to claim 1, characterized in that: The curing agent is 75% p-toluenesulfonic acid.

5. The carbon-based long-acting slow-release fertilizer according to claim 1, characterized in that: The carbon-based material is prepared according to the following steps: Mix the thermosetting resin and curing agent and stir evenly; Quickly pour into the preheated mold and dry in an oven to obtain a solidified material; crushing the solidified material to obtain solidified particles; The solidified particles are placed in a carbonization furnace for calcination and carbonization to obtain the carbon-based material.

6. The carbon-based long-acting slow-release fertilizer according to claim 5, characterized in that: The mold preheating temperature is 75℃~85℃, the oven drying temperature is 75℃~85℃, and the drying time is 15 min~20 min; The calcination and carbonization temperature is 700℃~950℃, the heating time is 2 h~3 h, and the constant temperature time is 2 h~8 h.

7. The carbon-based long-acting slow-release fertilizer according to claim 5, characterized in that: The particle size of the solidified particles is 2 mm to 3 mm.

8. The carbon-based long-acting slow-release fertilizer according to claim 5, characterized in that: During the constant temperature calcination stage, water vapor is introduced for activation.

9. A method for preparing the carbon-based long-acting slow-release fertilizer according to any one of claims 1 to 8, characterized in that: The following steps are involved: Melting the compound fertilizer and the thermosetting resin separately for later use; The carbon-based material is put into a granulator, and the melted compound fertilizer and thermosetting resin are put into the sprayer above the granulator respectively; While stirring the carbon-based material, compound fertilizer is sprayed in for fertilizer adsorption; After the carbon-based material has fully absorbed the fertilizer, continue stirring and start spraying thermosetting resin to coat the material with the resin; After the carbon-based material adsorbing the composite fertilizer is completely wrapped by the thermosetting resin, granulation is performed to obtain the carbon-based long-acting slow-release fertilizer.

10. The method for preparing the carbon-based long-acting slow-release fertilizer according to claim 9, characterized in that: The stirring speed of the granulator is 35 rpm~45 rpm; The spray rate of the sprayer is 8 L / min~15 L / min.

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