Inorganic composition synergistic sustained and controlled release urea fertilizer and preparation method and application method thereof

Abstract

The invention discloses an inorganic composition synergistic controlled-release urea fertilizer which comprises a mixture of the following components in percentage by weight: 50% of an inorganic composition and 50% of urea. Through composite granulation of inorganic compositions such as slate tailings, natural zeolite and the like and urea, the dissolution and release rate of urea is improved, and the dissolution rate and water leaching loss of urea are slowed down. The invention also discloses a preparation method and an application method of the synergistic sustained and controlled release urea fertilizer.

Description

Technical Field:

[0001] This application relates to urea fertilizers, and particularly to synergistic slow-release and controlled-release urea fertilizers and their preparation methods. Background Art:

[0002] Existing ordinary urea products are characterized by fast dissolution, easy volatilization, low utilization rate, short fertilizer efficiency, and easy environmental pollution. At the same time, ordinary urea with nitrogen as the main nutrient cannot provide some essential trace elements for crop growth, such as silicon, calcium, magnesium, iron, manganese, etc.

[0003] Existing synergistic slow-release and controlled-release urea fertilizers are either made by high-temperature and high-pressure synthesis and granulation tower granulation, such as disclosed in the Chinese patent application No. CN107827624A with the title of a synergistic slow-release and controlled-release urea fertilizer and its preparation process, or prepared by a coating process, such as disclosed in the Chinese patent application No. CN109206155 with the title of a method for preparing slow-release and controlled-release urea; and such as disclosed in the Chinese patent application No. CN108358706A with the title of a coated slow-release and controlled-release urea fertilizer and its preparation method. The above existing methods and their product preparation processes are complex, and the introduced coating substances have potential environmental pollution risks. Summary of the Invention:

[0004] The first object of the present invention is to provide a synergistic slow-release and controlled-release urea fertilizer containing an inorganic composition of slate tailings + natural zeolite.

[0005] To achieve this object, some embodiments of this application provide a synergistic slow-release and controlled-release urea fertilizer with an inorganic composition, including a mixture of the following components by weight percentage: 7% - 10% of slate tailings, 10% - 40% of natural zeolite, and 50% of urea.

[0006] Preferably, the synergistic slow-release and controlled-release urea fertilizer with an inorganic composition includes the following components by weight percentage: 10% of slate tailings, 40% of natural zeolite, and 50% of urea.

[0007] The synergistic slow-release and controlled-release urea fertilizer provided by the present invention can solve the problems of urea in the following aspects: 1) By compound granulation of slate tailings, natural zeolite and urea, the dissolution and release rate of urea are improved, and the dissolution rate and water leaching loss of urea are slowed down; 2) By adding slate tailings and natural zeolite, trace elements such as silicon, calcium, magnesium, iron, manganese, etc. required for crop growth are provided, and the comprehensive fertilizer efficiency of urea can be improved through the synergistic effect of multiple elements; 3) By adding slate tailings and natural zeolite, and utilizing their adsorption and ion exchange properties, urea is slowly released and the fertilizer efficiency is prolonged; 4) By adding slate tailings and natural zeolite, and utilizing their fine particle effect, the soil aggregate structure is improved, and the air permeability, water permeability of the soil and the growth characteristics of the root system are improved.

[0008] The second object of the present application is to provide a method for preparing the inorganic composition synergistic slow-release urea fertilizer described above.

[0009] To this end, some embodiments of the present application provide a method for preparing an inorganic composition synergistic slow-release urea fertilizer, which includes the following steps: separately processing massive slate tailings and natural zeolite, for example, using a Raymond mill to process them into powders with a particle size of minus 200 mesh accounting for ≥97%; mixing the massive slate tailings, natural zeolite powders and urea in a ratio of 7% - 10% of slate tailings, 10% - 40% of natural zeolite, and 50% of urea by weight percentage to obtain a mixed dry material; mixing the mixed dry material with 3% of water by weight of the mixed dry material to obtain a mixed wet material; using a pair-roll extrusion granulator to granulate, perform primary screening, drying, shaping, and secondary screening on the mixed wet material to obtain a nearly spherical slate tailings + natural zeolite composition synergistic slow-release urea fertilizer with a particle size of about 3 mm.

[0010] The present application also provides a method for preparing the inorganic composition synergistic slow-release urea fertilizer. By uniformly mixing various ureas with powders of inorganic material combinations such as slate tailings and natural zeolite, and through granulation, primary screening, drying, shaping, and secondary screening, a nearly spherical synergistic slow-release urea fertilizer with a particle size of about 3 mm is obtained. Using slate tailings and natural zeolite to provide trace elements such as silicon, calcium, magnesium, iron, and manganese required for crop growth, and exerting the synergistic effect of multiple elements to improve the comprehensive fertilizer efficiency of urea; using the adsorption and ion exchange properties of inorganic materials to slowly release urea and extend the fertilizer efficiency; using the micro-particle effect of the inorganic material combination to improve the soil aggregate structure, enhance the air permeability and water permeability of the soil, and the growth characteristics of the root system.

[0011] In addition, the present application also proposes an optimized ratio of the slate tailings plus natural zeolite inorganic composition and an extrusion granulation technology for the slate tailings plus natural zeolite inorganic composition synergistic slow-release urea fertilizer. Description of the drawings:

[0012] Figure 1 It is a flowchart of a method for preparing an inorganic composition synergistic slow-release urea fertilizer according to an embodiment of the present application;

[0013] Figure 2 It is a flowchart of a method for applying an inorganic composition synergistic slow-release urea fertilizer according to an embodiment of the present application;

[0014] Figure 3A It is a comparison chart of plant heights obtained from an experiment to verify the effect of the inorganic composition synergistic slow-release urea fertilizer of the present application;

[0015] Figure 3BChlorophyll comparison chart obtained from the experiment to verify the effect of the inorganic composition synergistic slow-release urea fertilizer of the present application;

[0016] Figure 3C Dry biomass comparison chart obtained from the experiment to verify the effect of the inorganic composition synergistic slow-release urea fertilizer of the present application;

[0017] Figure 3D Yield comparison chart obtained from the experiment to verify the effect of the inorganic composition synergistic slow-release urea fertilizer of the present application. Specific implementation manners:

[0018] The solution of the present application will be described in detail below with reference to the accompanying drawings.

[0019] The applicant found that mixing urea with specific inorganic substances or inorganic compositions can solve the problems of urea in the following aspects: First, by compound granulation of slate tailings, natural zeolite and urea, the dissolution and release rate of urea are improved, and the dissolution rate of urea and water leaching loss are slowed down. Second, by adding slate tailings and natural zeolite, trace elements such as silicon, calcium, magnesium, iron, and manganese required for crop growth are provided, and the comprehensive fertilizer efficiency of urea can be improved through the synergistic effect of multiple elements. Third, by adding slate tailings and natural zeolite, their adsorption and ion exchange properties are utilized to slowly release urea and extend the fertilizer efficiency. Fourth, by adding slate tailings and natural zeolite, their microparticle effect is utilized to improve the aggregate structure of the soil, and the air permeability, water permeability of the soil and the growth characteristics of the root system are improved.

[0020] Based on the above findings of the applicant, an inorganic composition synergistic slow-release urea fertilizer is proposed, which comprises the following components by weight percentage: about 50% of slate tailings and natural zeolite, and about 50% of urea. Among them, the ratio of slate tailings to natural zeolite can be 10-40% of slate tailings and 40-10% of natural zeolite; preferably 20-30% of slate tailings and 20-30% of natural zeolite.

[0021] The applicant found that among the inorganic composition synergistic slow-release urea fertilizers in different forms, the release effect of the granulated inorganic composition synergistic slow-release urea fertilizer is better. Especially the spherical inorganic composition synergistic slow-release urea fertilizer particles, especially the spherical inorganic composition synergistic slow-release urea fertilizer particles with a particle size of about 3 mm.

[0022] According to the national standard of urea GB / T2440-2017, the fertilizer particles are tested, and the technical indexes of the fertilizer particles are as follows:

[0023] The advantages of the present application will be demonstrated by describing the formulations, preparation processes, and application processes of the examples and comparative examples. Among them, slate tailings, natural zeolite, urea, potassium chloride, monoammonium phosphate, and compound fertilizer are all purchased from the conventional market.

[0024]

[0025] Example 1

[0026] An inorganic composition synergistic slow-release urea fertilizer, comprising the following components by weight percentage: 20% of slate tailings, 30% of natural zeolite, and 50% of urea.

[0027] The preparation method of the inorganic composition synergistic slow-release urea fertilizer is as Figure 1 shown and includes the following steps:

[0028] Step S100: Process the massive slate tailings and natural zeolite respectively with a Raymond mill into powders with a particle size ratio of -200 mesh particles ≥ 97%. Here, -200 mesh refers to the material taken under a 200-mesh sieve.

[0029] Step S200: Mix the massive slate tailings powder, natural zeolite powder, and urea evenly to obtain a mixed dry material.

[0030] Step S300: Mix the mixed dry material with 3% water by weight of the mixed dry material evenly to obtain a mixed wet material.

[0031] Step S400: Granulate, perform primary screening, drying, shaping, and secondary screening on the mixed wet material with a pair-roll extrusion granulator to obtain a near-spherical synergistic slow-release urea fertilizer with a particle size of about 3 mm.

[0032] Example 2

[0033] An inorganic composition synergistic slow-release urea fertilizer, comprising the following components by weight percentage: 40% of slate tailings, 10% of natural zeolite, and 50% of urea.

[0034] The preparation method of the inorganic composition synergistic slow-release urea fertilizer is the same as that of Example 1.

[0035] Example 3

[0036] An inorganic composition synergistic slow-release urea fertilizer, comprising the following components by weight percentage: 30% of slate tailings, 20% of natural zeolite, and 50% of urea.

[0037] The preparation method of the synergistic slow-release urea fertilizer is the same as that of Example 1.

[0038] Example 4

[0039] An inorganic composition synergistic slow-release urea fertilizer, comprising the following components by weight percentage: slate tailings 10%, natural zeolite 40%, urea 50%.

[0040] The preparation method of the inorganic composition synergistic slow-release urea fertilizer is the same as that of Example 1.

[0041] Comparative Example 1

[0042] Do not use the above inorganic composition synergistic slow-release urea fertilizer, and only apply commercially available compound fertilizer per mu, with the equivalent N, P2O5, and K2O contents being 7.5 kg, 7.5 kg, and 7.5 kg per mu respectively.

[0043] Comparative Example 2

[0044] Do not use the above inorganic composition synergistic slow-release urea fertilizer, and only apply commercially available compound fertilizer per mu, with the equivalent N, P2O5, and K2O contents being 9.0 kg, 9.0 kg, and 9.0 kg per mu respectively.

[0045] The test method is as Figure 2 shown:

[0046] Select a farmland in Zhaocun, Panggezhuang Town, Daxing District, Beijing as the test field, which has irrigation conditions. The soil belongs to fluvo-aquic soil, and the soil texture and nutrient contents such as soil nitrogen, phosphorus, and potassium are roughly the same. A total of 6 treatment groups are set in the test, and each treatment is repeated 3 times, and the plots are randomly arranged; the area of each plot is 1 mu.

[0047] Step S801: The inorganic composition synergistic slow-release urea fertilizers prepared in Examples 1 to 4 are respectively compounded and mixed with commercially available potassium chloride and monoammonium phosphate and used as base fertilizers, and are turned into the plough layer of 1 to 20 cm according to the normal farming system one day before sowing.

[0048] Step S802: Adjust the fertilizer content in the plots so that the base fertilizers applied to all the treatment plots in Examples 1 to 4, including the inorganic composition synergistic slow-release urea fertilizer and commercially available potassium chloride and monoammonium phosphate, have the equivalent amounts of N, P2O5, and K2O of 7.5 kg;

[0049] For Comparative Example 1, the above synergistic slow-release urea fertilizer is not applied as the base fertilizer, but commercially available compound fertilizer is applied in an amount equivalent to 7.5 kg of N, P2O5, and K2O per mu respectively. For example, a compound fertilizer with a specification of N = 15%, P2O5 = 15%, and K2O = 15% is used.

[0050] For Comparative Example 2, the above synergistic slow-release urea fertilizer is not applied as the base fertilizer, but commercially available compound fertilizer is applied in an amount equivalent to 9.0 kg of N, P2O5, and K2O per mu respectively. For example, a compound fertilizer with a specification of N = 15%, P2O5 = 15%, and K2O = 15% is used.

[0051] Step S803: Maize was sown by machine at the beginning of May 2021. In the jointing stage, both the treatment group and the control group topdressed with 20 kg of commercially available urea per mu. After the autumn harvest, the maize grain yield per mu and the nitrogen content of maize grains in Examples 1 to 4, Comparative Example 1 and Comparative Example 1 were measured according to the agricultural yield measurement rules, and the results are shown in Table 1.

[0052] Table 1 Maize Yield and Grain Nitrogen Content of Examples and Comparative Examples

[0053]

[0054] Specification

[0055]

[0056] Table 1 shows that compared with Comparative Example 1, the inorganic composition synergistic slow-release urea fertilizer corresponding to the embodiments of the present invention has significantly improved both the maize yield and the nitrogen content of grains. Among them, the inorganic composition slow-release urea in Example 4 has the best effect; although the application rates of N, P2O5, and K2O in Comparative Example 2 are 20% higher than those in Examples 1 to 4 and their Comparative Example 1, its maize yield and grain nitrogen content are still lower than those in Examples 1 to 4.

[0057] In 2023, the applicant commissioned the Institute of Plant Nutrition and Resources Environment, Beijing Academy of Agriculture and Forestry Sciences to conduct a comparative field experiment of the compound fertilizer based on the synergistic slow-release urea of this application and the conventional compound fertilizer. The field soil is light (sandy) fluvo-aquic soil, and its physical and chemical properties are: organic matter 14.5 g / kg, total nitrogen 0.84 g / kg, available phosphorus 52.64 mg / kg, available potassium 71 mg / kg, and pH 8.4.

[0058] The compound fertilizer based on the synergistic slow-release urea of this application contains 20.1 kg / mu of synergistic slow-release urea, 16.3 kg / mu of diamine (18-46-0), and 12.5 kg / mu of potassium chloride (60%). The conventional compound fertilizer is in the ratio of 15%-15%-15% and is 50 kg / mu. The effect of reducing the application rate of synergistic urea was also verified in the experiment. According to the application of fertilizer in N-P2O5-K2O (15-15-15), with a fertilizer application rate of 40 kg / mu (15-15-15), then 13 kg / mu of diamine, 7.9 kg / mu of urea, and 10 kg / mu of potassium chloride fertilizer are applied.

[0059] Figures 3A to 3DBar charts showing the plant height, chlorophyll, dry biomass, comparison, and final yield of the above field experiments. In the figure, the enhanced urea refers to the compound fertilizer of the enhanced slow-release and controlled-release urea of the present application, and the enhanced reduction refers to the reduced fertilization of the enhanced urea. It can be seen from the figure that although there are no obvious differences in various indicators such as plant height and chlorophyll in the early stage, the dry matter weight and final yield in the later growth stage are the highest with the enhanced slow-release and controlled-release urea, significantly higher than those of the conventional compound fertilizer treatment by 10.16%, and the reduced enhanced slow-release and controlled-release urea ranks second. The above results fully show that in the sandy land with water and fertilizer leakage, the enhanced slow-release and controlled-release materials do have an adsorption and re-release supply effect on nutrients. Combining with the biomass of the soil column simulation experiment, the enhanced slow-release and controlled-release urea plays a role in increasing production and achieves the purpose of "reducing fertilizer and increasing efficiency".

Claims

1. An inorganic composition synergistic slow-release and controlled-release urea fertilizer, characterized in that: A mixture comprising the following components by weight percentage: 50% inorganic composition and 50% urea.

2. The inorganic composition synergistic slow-release and controlled-release urea fertilizer according to claim 1, wherein: The components of the inorganic mixture are 7% - 10% slate tailings and 10% - 40% natural zeolite by weight percentage.

3. The inorganic composition synergistic slow-release and controlled-release urea fertilizer according to claim 1 or 2, characterized in that: The inorganic composition synergistic slow-release urea fertilizer is a dry material, a wet material or granules.

4. The inorganic composition synergistic slow-release urea fertilizer according to claim 3, characterized in that: The inorganic composition synergistic slow-release urea fertilizer is nearly spherical granules with a particle size of about 3 mm.

5. The inorganic composition synergistic slow-release urea fertilizer according to claim 4, characterized in that: For the spherical granules, the mass fraction of total nitrogen ≥ 23; the mass fraction of biuret ≤ 0.9; the moisture ≤ 0.

5.

6. The preparation method of the inorganic composition synergistic slow-release urea fertilizer according to claim 4, characterized in that: It includes the steps of processing the massive slate tailings and the natural zeolite into powders with a proportion of particles passing through 200-mesh sieve ≥ 97%; Mixing the powders of the slate tailings and the natural zeolite with urea evenly to obtain a mixed dry material; Mixing the mixed dry material with water accounting for 3% of the weight of the mixed dry material evenly to obtain a mixed wet material; Performing granulation and subsequent processes on the mixed wet material to obtain the nearly spherical granules with a particle size of 3 mm.

7. Method for applying inorganic composition synergistic slow and controlled release urea fertilizer, characterized in that: Mixing the inorganic composition synergistic slow-release urea fertilizer of any one of claims 1 to 6 with commercially available potassium chloride and monoammonium phosphate respectively and then using them as base fertilizers, and turning them into the plough layer according to the conventional tillage system before farming; wherein, the amounts of N, P2O5, and K2O in the base fertilizers are equal; the plough layer is a plough layer of 1 to 20 cm.

8. Method for planting corn with inorganic composition synergistic slow-release urea fertilizer, characterized in that: Mixing the inorganic composition synergistic slow-release urea fertilizer of any one of claims 1 to 6 with commercially available potassium chloride and monoammonium phosphate respectively and then using them as base fertilizers, and turning them into a plough layer of 1 to 20 cm according to the conventional tillage system before farming, wherein the amounts of N, P2O5, and K2O in the base fertilizers are equal, all being 7.5 kg per mu.

9. The method for growing corn with the inorganic composition synergistic slow-release urea fertilizer according to claim 8, characterized in that: Topdressing urea at 20 kg per mu at the jointing stage.

10. A method for planting corn with an inorganic composition synergistic slow-release urea fertilizer, characterized in that: Applying the synergistic slow-release urea fertilizer of any one of claims 1 to 6 at 20.1 kg / mu, diamine (18 - 46 - 0) at 16.3 kg / mu, potassium chloride (60%) at 12.5 kg / mu; or applying the synergistic slow-release urea fertilizer at 7.9 kg / mu, diamine at 13 kg / mu, and potassium chloride fertilizer at 10 kg / mu.

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