Preparation method of nitrate-containing compound fertilizer

Abstract

The invention discloses a preparation method of a nitrate-containing compound fertilizer, and relates to the field of compound fertilizers, and the nitrate-containing compound fertilizer is prepared from the following components in parts by weight: 10-15 parts of nitrate, 3-10 parts of monoammonium phosphate, 3-8 parts of ammonium bicarbonate, 0.5-2 parts of urea and 1-2 parts of coated diatomite. According to the preparation method disclosed by the invention, by preparing the coated diatomite, the water absorption capacity of the diatomite is weakened, the water absorption rate of the diatomite can be controlled in a range of 0.5-1 time from 2-4 times of the water absorption rate of the diatomite, and the volume of the diatomite has variability while a certain water absorption rate is maintained; water and soil loss is avoided, moisture in soil is kept, and therefore fertility can better act on plant roots.

Description

Technical Field

[0001] The invention relates to the field of compound fertilizers, and in particular to a method for preparing a nitrate-containing compound fertilizer. Background Art

[0002] Compound fertilizer refers to chemical fertilizer containing two or more nutrient elements of nitrogen, phosphorus and potassium. Compound fertilizer has the advantages of high nutrient content, few by-components and good physical properties. It plays a very important role in balanced fertilization, improving fertilizer utilization and promoting high and stable yields of crops.

[0003] However, the nutrients of compound fertilizer applied in the soil are easily released rapidly with soil erosion, and the continuous supply capacity of nutrients is insufficient. Therefore, it is necessary to propose a preparation method of nitrate-containing compound fertilizer to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a nitrate-containing compound fertilizer to solve the problem that the nutrients of the compound fertilizer applied in the soil are easily released rapidly with soil erosion and the continuous supply capacity of the nutrients is insufficient.

[0005] To achieve the above object, the present invention provides the following technical scheme: a method for preparing a nitrate-containing compound fertilizer, comprising 10-15 parts by weight of nitrate, 3-10 parts by weight of monoammonium phosphate, 3-8 parts by weight of ammonium bicarbonate, 0.5-2 parts by weight of urea, and 1-2 parts by weight of coated diatomaceous earth;

[0006] The method for preparing the nitrate-containing compound fertilizer comprises the following steps:

[0007] S1: Prepare slurry, add nitrate, monoammonium phosphate, ammonium bicarbonate, urea and water to form slurry by ultrasonic mixing, the ultrasonic wave is generated by an ultrasonic generator, the ultrasonic wave frequency generated by the ultrasonic generator is 30-50kHz, the power of the ultrasonic generator is 200-300W, and the slurry is placed in a pressure tank for pressurization during mixing, and stirred for 1-2h to form a slurry with a fluidity of 2-5cm;

[0008] S2: Drying the slurry. Dry the slurry with a fluidity of 2-5 cm to a paste state. The fluidity loss of the slurry in the paste state is less than 3 mm within 30 minutes.

[0009] S3: Granulation, using a granulator to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles;

[0010] S4: coating, adding the coated diatomaceous earth to the nitrate-containing compound fertilizer particles and stirring, stirring and mixing for 30-40 minutes, and then drying the nitrate-containing compound fertilizer particles to form a coated nitrate-containing compound fertilizer.

[0011] Preferably, the components by weight include 10 parts of nitrate, 3 parts of monoammonium phosphate, 3 parts of ammonium bicarbonate, 0.5 parts of urea, and 1 part of coated diatomaceous earth.

[0012] Preferably, the components by weight include 12 parts of nitrate, 5 parts of monoammonium phosphate, 4 parts of ammonium bicarbonate, 1 part of urea, and 1.2 parts of coated diatomaceous earth.

[0013] Preferably, the components by weight include 13 parts of nitrate, 8 parts of monoammonium phosphate, 5 parts of ammonium bicarbonate, 1.5 parts of urea, and 1.5 parts of coated diatomaceous earth.

[0014] Preferably, the components by weight include 15 parts of nitrate, 10 parts of monoammonium phosphate, 8 parts of ammonium bicarbonate, 2 parts of urea, and 2 parts of coated diatomaceous earth.

[0015] Preferably, the pressurization condition in S1 is 0.1-1 MPa, and the temperature in the pressure tank is 20-40 degrees Celsius.

[0016] Preferably, the nitrate ions are taken from polishing and cleaning wastewater in the aluminum industry.

[0017] Preferably, in S4, the nitrate-containing compound fertilizer particles are dried to a moisture content of less than 30%.

[0018] Preferably, the method for preparing the coated diatomite comprises the following steps:

[0019] A1: Prepare materials, including diatomaceous earth, yellow mud and water. Grind the diatomaceous earth and yellow mud to form diatomaceous earth powder and yellow mud powder with a particle size of less than 0.002 mm.

[0020] A2: To prepare coated diatomaceous earth, diatomaceous earth powder, yellow clay powder and water are mixed and stirred to form a slurry-like coated diatomaceous earth.

[0021] Technical effects and advantages of the present invention:

[0022] 1. In the present invention, the water absorption capacity of diatomaceous earth is weakened by preparing coated diatomaceous earth, and the water absorption rate of diatomaceous earth itself can be controlled within the range of 0.5-1 times, which is 2-4 times of itself. While maintaining a certain water absorption rate, its volume is variable. When the coated diatomaceous earth is coated on the outer surface of the nitrate-containing compound fertilizer particles, it can prevent soil erosion and maintain moisture in the soil, so that the fertility can better act on the roots of plants;

[0023] 2. When the volume of the coated diatomaceous earth changes, the volume change is 0.5-1 times of its own volume. The range is reasonably controlled. The expansion and contraction process of the volume change has a certain loosening effect on the soil, and will not excessively loosen the soil, thus ensuring the air permeability of the plant roots.

[0024] 3. With the change of weather, such as drought, the coated diatomite shrinks, and the nitrate compound fertilizer will not be discharged due to the isolation effect of the surface film. When the weather is cool, the diatomite expands to a certain extent, so that the fertility contained in the diatomite inside the film is gradually released through the holes on the film, thereby releasing the fertility, ensuring that the fertility is released during drought and does not cause the fertility to volatilize or lose;

[0025] 4. In the present invention, the slurry in the paste state is granulated by a granulator to form nitrate-containing compound fertilizer particles, which can effectively increase the storage time of the nitrate-containing compound fertilizer, and according to the size of the prepared nitrate-containing compound fertilizer particles, the continuous supply time of fertility can also be effectively increased;

[0026] 5. Nitrate is taken from the polishing and cleaning wastewater of the aluminum industry. Usually, the polishing and cleaning wastewater containing phosphate, nitrate, sulfate and nickel ions is collected, which solves the problem of high cost of waste slag treatment containing phosphorus and nickel in the polishing waste liquid and high environmental protection cost in the prior art; and nitrate is negatively charged and is not easily adsorbed by soil colloids mainly with negative charge; it is not easy to acidify the soil and can neutralize the soil acidity;

[0027] 6. The diatomite powder, yellow mud powder and water in the present invention are easily mixed to form a dense protective film. When this protective film is coated on the outer surface of the nitrate-containing compound fertilizer, it can effectively reduce the loss of fertility. In addition, by utilizing the expansion property of the diatomite itself, the fertility can be added to the soil at an appropriate time, such as when it rains or when the weather is good, which is beneficial for the roots of crops to increase the absorption of fertility. Under conditions such as drought, the water absorbed by the roots of plants is limited and it is not suitable for fertilization. Therefore, the nutrients are stored in the coated diatomite and are not easily lost.

[0028] 7. The effective combination of yellow mud and diatomaceous earth takes into account the effects of retaining water, preventing the loss of nutrients, and expelling nutrients and water when needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a diagram of the preparation method of the nitrate-containing compound fertilizer of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0031] Embodiment 1, the present invention provides as Figure 1The preparation method of the nitrate-containing compound fertilizer shown includes 10 parts of nitrate, 3 parts of monoammonium phosphate, 3 parts of ammonium bicarbonate, 0.5 parts of urea, and 1 part of coated diatomaceous earth according to weight components;

[0032] In the present invention, the coated diatomaceous earth is prepared so that the water absorption capacity of the diatomaceous earth is weakened, and the water absorption rate of the diatomaceous earth itself can be controlled within the range of 0.5-1 times, which is 2-4 times of itself. While maintaining a certain water absorption rate, its volume is variable. When the coated diatomaceous earth is coated on the outer surface of the nitrate-containing compound fertilizer particles, it can prevent soil erosion and maintain moisture in the soil, so that the fertility can better act on the roots of plants.

[0033] Furthermore, when the volume of the coated diatomaceous earth changes, the volume change is 0.5-1 times of its own volume, and the range is reasonably controlled. The expansion and contraction process of the volume change has a certain relaxing effect on the soil, and will not excessively relax the soil, thereby ensuring the air permeability of the plant roots.

[0034] As the weather changes, such as drought, the coated diatomaceous earth shrinks, and the fertility of the nitrate-containing compound fertilizer will not be discharged due to the insulating effect of the surface coating. When the weather is cool, the diatomaceous earth expands to a certain extent, so that the fertility contained in the diatomaceous earth inside the coating is gradually released through the holes in the membrane, thereby releasing the fertility, ensuring that the fertility is released during drought and does not cause volatilization or loss of fertility.

[0035] In actual use, depending on the particle size of the nitrate-containing compound fertilizer produced, it can effectively ensure a continuous supply of fertilizer for more than 5 years.

[0036] The method for preparing the nitrate-containing compound fertilizer comprises the following steps:

[0037] S1: Prepare slurry, add nitrate, monoammonium phosphate, ammonium bicarbonate, urea and water to ultrasonically mix to form slurry, the ultrasonic wave is generated by an ultrasonic generator, the ultrasonic frequency generated by the ultrasonic generator is 30-50kHz, the power of the ultrasonic generator is 200-300W, the slurry is placed in a pressure tank for pressurization during mixing, and stirred for 1-2h to form a slurry with a fluidity of 2-5cm, the pressurization condition in S1 is 0.1-1MPa, and the temperature in the pressure tank is 20-40 degrees Celsius;

[0038] S2: Drying the slurry. Dry the slurry with a fluidity of 2-5 cm to a paste state. The fluidity loss of the slurry in the paste state is less than 3 mm within 30 minutes.

[0039] S3: Granulation, using a granulator to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles;

[0040] S4: coating, adding the coated diatomaceous earth to the nitrate-containing compound fertilizer particles and stirring, after stirring and mixing for 30-40 minutes, drying the nitrate-containing compound fertilizer particles to form coated nitrate-containing compound fertilizer, in S4, drying the nitrate-containing compound fertilizer particles to a moisture content of less than 30%.

[0041] In the present invention, a granulator is used to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles, which can effectively increase the storage time of the nitrate-containing compound fertilizer, and according to the size of the prepared nitrate-containing compound fertilizer particles, the continuous supply time of fertilizer can also be effectively increased.

[0042] Nitrate is taken from the polishing and cleaning wastewater of the aluminum industry. Usually, polishing and cleaning wastewater containing phosphate, nitrate, sulfate and nickel ions is collected, which solves the problems of high cost and high environmental protection cost of waste slag treatment containing phosphorus and nickel in the polishing waste liquid in the prior art. Nitrate is negatively charged and is not easily adsorbed by soil colloids that are mainly negatively charged. It is not easy to acidify the soil and can neutralize the soil acidity.

[0043] The preparation method of coated diatomite comprises the following steps:

[0044] A1: Prepare materials, including diatomaceous earth, yellow mud and water. Grind the diatomaceous earth and yellow mud to form diatomaceous earth powder and yellow mud powder with a particle size of less than 0.002 mm.

[0045] A2: To prepare coated diatomaceous earth, diatomaceous earth powder, yellow clay powder and water are mixed and stirred to form a slurry-like coated diatomaceous earth.

[0046] In the present invention, diatomite powder, yellow mud powder and water are easily mixed to form a dense protective film. When the protective film is coated on the outer surface of the nitrate-containing compound fertilizer, the loss of fertility can be effectively reduced. The expansion performance of the diatomite itself is utilized to accelerate the addition of fertility to the soil at a suitable time, such as when it rains or when the weather is good, which is beneficial for the roots of crops to increase the absorption of fertility. Under conditions such as drought, the water absorbed by the roots of plants is limited and it is not suitable for fertilization. Therefore, the nutrients are stored in the coated diatomite and are not easily lost.

[0047] Yellow mud has good permeability and adsorption properties, which can effectively prevent water penetration and leakage. Therefore, the effective combination of yellow mud and diatomaceous earth can take into account the effects of retaining water, preventing the loss of nutrients, and expelling nutrients and water when needed.

[0048] Embodiment 2, the present invention provides as Figure 1 The preparation method of the nitrate-containing compound fertilizer shown includes 12 parts of nitrate, 5 parts of monoammonium phosphate, 4 parts of ammonium bicarbonate, 1 part of urea, and 1.2 parts of coated diatomaceous earth according to weight components;

[0049] In the present invention, the coated diatomaceous earth is prepared so that the water absorption capacity of the diatomaceous earth is weakened, and the water absorption rate of the diatomaceous earth itself can be controlled within the range of 0.5-1 times, which is 2-4 times of itself. While maintaining a certain water absorption rate, its volume is variable. When the coated diatomaceous earth is coated on the outer surface of the nitrate-containing compound fertilizer particles, it can prevent soil erosion and maintain moisture in the soil, so that the fertility can better act on the roots of plants.

[0050] Furthermore, when the volume of the coated diatomaceous earth changes, the volume change is 0.5-1 times of its own volume, and the range is reasonably controlled. The expansion and contraction process of the volume change has a certain relaxing effect on the soil, and will not excessively relax the soil, thereby ensuring the air permeability of the plant roots.

[0051] As the weather changes, such as drought, the coated diatomaceous earth shrinks, and the fertility of the nitrate-containing compound fertilizer will not be discharged due to the insulating effect of the surface coating. When the weather is cool, the diatomaceous earth expands to a certain extent, so that the fertility contained in the diatomaceous earth inside the coating is gradually released through the holes in the membrane, thereby releasing the fertility, ensuring that the fertility is released during drought and does not cause volatilization or loss of fertility.

[0052] In actual use, depending on the particle size of the nitrate-containing compound fertilizer produced, it can effectively ensure a continuous supply of fertilizer for more than 5 years.

[0053] The method for preparing the nitrate-containing compound fertilizer comprises the following steps:

[0054] S1: Prepare slurry, add nitrate, monoammonium phosphate, ammonium bicarbonate, urea and water to ultrasonically mix to form slurry, the ultrasonic wave is generated by an ultrasonic generator, the ultrasonic frequency generated by the ultrasonic generator is 30-50kHz, the power of the ultrasonic generator is 200-300W, the slurry is placed in a pressure tank for pressurization during mixing, and stirred for 1-2h to form a slurry with a fluidity of 2-5cm, the pressurization condition in S1 is 0.1-1MPa, and the temperature in the pressure tank is 20-40 degrees Celsius;

[0055] S2: Drying the slurry. Dry the slurry with a fluidity of 2-5 cm to a paste state. The fluidity loss of the slurry in the paste state is less than 3 mm within 30 minutes.

[0056] S3: Granulation, using a granulator to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles;

[0057] S4: coating, adding the coated diatomaceous earth to the nitrate-containing compound fertilizer particles and stirring, after stirring and mixing for 30-40 minutes, drying the nitrate-containing compound fertilizer particles to form coated nitrate-containing compound fertilizer, in S4, drying the nitrate-containing compound fertilizer particles to a moisture content of less than 30%.

[0058] In the present invention, a granulator is used to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles, which can effectively increase the storage time of the nitrate-containing compound fertilizer, and according to the size of the prepared nitrate-containing compound fertilizer particles, the continuous supply time of fertilizer can also be effectively increased.

[0059] Nitrate is taken from the polishing and cleaning wastewater of the aluminum industry. Usually, polishing and cleaning wastewater containing phosphate, nitrate, sulfate and nickel ions is collected, which solves the problems of high cost and high environmental protection cost of waste slag treatment containing phosphorus and nickel in the polishing waste liquid in the prior art. Nitrate is negatively charged and is not easily adsorbed by soil colloids that are mainly negatively charged. It is not easy to acidify the soil and can neutralize the soil acidity.

[0060] The preparation method of coated diatomite comprises the following steps:

[0061] A1: Prepare materials, including diatomaceous earth, yellow mud and water. Grind the diatomaceous earth and yellow mud to form diatomaceous earth powder and yellow mud powder with a particle size of less than 0.002 mm.

[0062] A2: To prepare coated diatomaceous earth, diatomaceous earth powder, yellow clay powder and water are mixed and stirred to form a slurry-like coated diatomaceous earth.

[0063] In the present invention, diatomite powder, yellow mud powder and water are easily mixed to form a dense protective film. When the protective film is coated on the outer surface of the nitrate-containing compound fertilizer, the loss of fertility can be effectively reduced. The expansion performance of the diatomite itself is utilized to accelerate the addition of fertility to the soil at a suitable time, such as when it rains or when the weather is good, which is beneficial for the roots of crops to increase the absorption of fertility. Under conditions such as drought, the water absorbed by the roots of plants is limited and it is not suitable for fertilization. Therefore, the nutrients are stored in the coated diatomite and are not easily lost.

[0064] Yellow mud has good permeability and adsorption properties, which can effectively prevent water penetration and leakage. Therefore, the effective combination of yellow mud and diatomaceous earth can take into account the effects of retaining water, preventing the loss of nutrients, and expelling nutrients and water when needed.

[0065] Embodiment 3, the present invention provides as Figure 1 The preparation method of the nitrate-containing compound fertilizer shown includes 13 parts of nitrate, 8 parts of monoammonium phosphate, 5 parts of ammonium bicarbonate, 1.5 parts of urea, and 1.5 parts of coated diatomaceous earth according to weight components;

[0066] In the present invention, the coated diatomaceous earth is prepared so that the water absorption capacity of the diatomaceous earth is weakened, and the water absorption rate of the diatomaceous earth itself can be controlled within the range of 0.5-1 times, which is 2-4 times of itself. While maintaining a certain water absorption rate, its volume is variable. When the coated diatomaceous earth is coated on the outer surface of the nitrate-containing compound fertilizer particles, it can prevent soil erosion and maintain moisture in the soil, so that the fertility can better act on the roots of plants.

[0067] Furthermore, when the volume of the coated diatomaceous earth changes, the volume change is 0.5-1 times of its own volume, and the range is reasonably controlled. The expansion and contraction process of the volume change has a certain relaxing effect on the soil, and will not excessively relax the soil, thereby ensuring the air permeability of the plant roots.

[0068] As the weather changes, such as drought, the coated diatomaceous earth shrinks, and the fertility of the nitrate-containing compound fertilizer will not be discharged due to the insulating effect of the surface coating. When the weather is cool, the diatomaceous earth expands to a certain extent, so that the fertility contained in the diatomaceous earth inside the coating is gradually released through the holes in the membrane, thereby releasing the fertility, ensuring that the fertility is released during drought and does not cause volatilization or loss of fertility.

[0069] In actual use, depending on the particle size of the nitrate-containing compound fertilizer produced, it can effectively ensure a continuous supply of fertilizer for more than 5 years.

[0070] The method for preparing the nitrate-containing compound fertilizer comprises the following steps:

[0071] S1: Prepare slurry, add nitrate, monoammonium phosphate, ammonium bicarbonate, urea and water to ultrasonically mix to form slurry, the ultrasonic wave is generated by an ultrasonic generator, the ultrasonic frequency generated by the ultrasonic generator is 30-50kHz, the power of the ultrasonic generator is 200-300W, the slurry is placed in a pressure tank for pressurization during mixing, and stirred for 1-2h to form a slurry with a fluidity of 2-5cm, the pressurization condition in S1 is 0.1-1MPa, and the temperature in the pressure tank is 20-40 degrees Celsius;

[0072] S2: Drying the slurry. Dry the slurry with a fluidity of 2-5 cm to a paste state. The fluidity loss of the slurry in the paste state is less than 3 mm within 30 minutes.

[0073] S3: Granulation, using a granulator to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles;

[0074] S4: coating, adding the coated diatomaceous earth to the nitrate-containing compound fertilizer particles and stirring, after stirring and mixing for 30-40 minutes, drying the nitrate-containing compound fertilizer particles to form coated nitrate-containing compound fertilizer, in S4, drying the nitrate-containing compound fertilizer particles to a moisture content of less than 30%.

[0075] In the present invention, a granulator is used to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles, which can effectively increase the storage time of the nitrate-containing compound fertilizer, and according to the size of the prepared nitrate-containing compound fertilizer particles, the continuous supply time of fertilizer can also be effectively increased.

[0076] Nitrate is taken from the polishing and cleaning wastewater of the aluminum industry. Usually, polishing and cleaning wastewater containing phosphate, nitrate, sulfate and nickel ions is collected, which solves the problems of high cost and high environmental protection cost of waste slag treatment containing phosphorus and nickel in the polishing waste liquid in the prior art. Nitrate is negatively charged and is not easily adsorbed by soil colloids that are mainly negatively charged. It is not easy to acidify the soil and can neutralize the soil acidity.

[0077] The preparation method of coated diatomite comprises the following steps:

[0078] A1: Prepare materials, including diatomaceous earth, yellow mud and water. Grind the diatomaceous earth and yellow mud to form diatomaceous earth powder and yellow mud powder with a particle size of less than 0.002 mm.

[0079] A2: To prepare coated diatomaceous earth, diatomaceous earth powder, yellow clay powder and water are mixed and stirred to form a slurry-like coated diatomaceous earth.

[0080] In the present invention, diatomite powder, yellow mud powder and water are easily mixed to form a dense protective film. When the protective film is coated on the outer surface of the nitrate-containing compound fertilizer, the loss of fertility can be effectively reduced. The expansion performance of the diatomite itself is utilized to accelerate the addition of fertility to the soil at a suitable time, such as when it rains or when the weather is good, which is beneficial for the roots of crops to increase the absorption of fertility. Under conditions such as drought, the water absorbed by the roots of plants is limited and it is not suitable for fertilization. Therefore, the nutrients are stored in the coated diatomite and are not easily lost.

[0081] Yellow mud has good permeability and adsorption properties, which can effectively prevent water penetration and leakage. Therefore, the effective combination of yellow mud and diatomaceous earth can take into account the effects of retaining water, preventing the loss of nutrients, and expelling nutrients and water when needed.

[0082] Embodiment 4, the present invention provides as Figure 1 The preparation method of the nitrate-containing compound fertilizer shown includes 15 parts of nitrate, 10 parts of monoammonium phosphate, 8 parts of ammonium bicarbonate, 2 parts of urea, and 2 parts of coated diatomaceous earth according to weight components;

[0083] In the present invention, the coated diatomaceous earth is prepared so that the water absorption capacity of the diatomaceous earth is weakened, and the water absorption rate of the diatomaceous earth itself can be controlled within the range of 0.5-1 times, which is 2-4 times of itself. While maintaining a certain water absorption rate, its volume is variable. When the coated diatomaceous earth is coated on the outer surface of the nitrate-containing compound fertilizer particles, it can prevent soil erosion and maintain moisture in the soil, so that the fertility can better act on the roots of plants.

[0084] Furthermore, when the volume of the coated diatomaceous earth changes, the volume change is 0.5-1 times of its own volume, and the range is reasonably controlled. The expansion and contraction process of the volume change has a certain relaxing effect on the soil, and will not excessively relax the soil, thereby ensuring the air permeability of the plant roots.

[0085] As the weather changes, such as drought, the coated diatomaceous earth shrinks, and the fertility of the nitrate-containing compound fertilizer will not be discharged due to the insulating effect of the surface coating. When the weather is cool, the diatomaceous earth expands to a certain extent, so that the fertility contained in the diatomaceous earth inside the coating is gradually released through the holes in the membrane, thereby releasing the fertility, ensuring that the fertility is released during drought and does not cause volatilization or loss of fertility.

[0086] In actual use, depending on the particle size of the nitrate-containing compound fertilizer produced, it can effectively ensure a continuous supply of fertilizer for more than 5 years.

[0087] The method for preparing the nitrate-containing compound fertilizer comprises the following steps:

[0088] S1: Prepare slurry, add nitrate, monoammonium phosphate, ammonium bicarbonate, urea and water to ultrasonically mix to form slurry, the ultrasonic wave is generated by an ultrasonic generator, the ultrasonic frequency generated by the ultrasonic generator is 30-50kHz, the power of the ultrasonic generator is 200-300W, the slurry is placed in a pressure tank for pressurization during mixing, and stirred for 1-2h to form a slurry with a fluidity of 2-5cm, the pressurization condition in S1 is 0.1-1MPa, and the temperature in the pressure tank is 20-40 degrees Celsius;

[0089] S2: Drying the slurry. Dry the slurry with a fluidity of 2-5 cm to a paste state. The fluidity loss of the slurry in the paste state is less than 3 mm within 30 minutes.

[0090] S3: Granulation, using a granulator to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles;

[0091] S4: coating, adding the coated diatomaceous earth to the nitrate-containing compound fertilizer particles and stirring, after stirring and mixing for 30-40 minutes, drying the nitrate-containing compound fertilizer particles to form coated nitrate-containing compound fertilizer, in S4, drying the nitrate-containing compound fertilizer particles to a moisture content of less than 30%.

[0092] In the present invention, a granulator is used to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles, which can effectively increase the storage time of the nitrate-containing compound fertilizer, and according to the size of the prepared nitrate-containing compound fertilizer particles, the continuous supply time of fertilizer can also be effectively increased.

[0093] Nitrate is taken from the polishing and cleaning wastewater of the aluminum industry. Usually, polishing and cleaning wastewater containing phosphate, nitrate, sulfate and nickel ions is collected, which solves the problems of high cost and high environmental protection cost of waste slag treatment containing phosphorus and nickel in the polishing waste liquid in the prior art. Nitrate is negatively charged and is not easily adsorbed by soil colloids that are mainly negatively charged. It is not easy to acidify the soil and can neutralize the soil acidity.

[0094] The preparation method of coated diatomite comprises the following steps:

[0095] A1: Prepare materials, including diatomaceous earth, yellow mud and water. Grind the diatomaceous earth and yellow mud to form diatomaceous earth powder and yellow mud powder with a particle size of less than 0.002 mm.

[0096] A2: To prepare coated diatomaceous earth, diatomaceous earth powder, yellow clay powder and water are mixed and stirred to form a slurry-like coated diatomaceous earth.

[0097] In the present invention, diatomite powder, yellow mud powder and water are easily mixed to form a dense protective film. When the protective film is coated on the outer surface of the nitrate-containing compound fertilizer, the loss of fertility can be effectively reduced. The expansion performance of the diatomite itself is utilized to accelerate the addition of fertility to the soil at a suitable time, such as when it rains or when the weather is good, which is beneficial for the roots of crops to increase the absorption of fertility. Under conditions such as drought, the water absorbed by the roots of plants is limited and it is not suitable for fertilization. Therefore, the nutrients are stored in the coated diatomite and are not easily lost.

[0098] Yellow mud has good permeability and adsorption properties, which can effectively prevent water penetration and leakage. Therefore, the effective combination of yellow mud and diatomaceous earth can take into account the effects of retaining water, preventing the loss of nutrients, and expelling nutrients and water when needed.

Claims

1. A method for preparing a nitrate-containing compound fertilizer, characterized in that: The components by weight include 10-15 parts of nitrate, 3-10 parts of monoammonium phosphate, 3-8 parts of ammonium bicarbonate, 0.5-2 parts of urea, and 1-2 parts of coated diatomaceous earth; The method for preparing the nitrate-containing compound fertilizer comprises the following steps: S1: Prepare slurry, add nitrate, monoammonium phosphate, ammonium bicarbonate, urea and water to form slurry by ultrasonic mixing, the ultrasonic wave is generated by an ultrasonic generator, the ultrasonic wave frequency generated by the ultrasonic generator is 30-50kHz, the power of the ultrasonic generator is 200-300W, and the slurry is placed in a pressure tank for pressurization during mixing, and stirred for 1-2h to form a slurry with a fluidity of 2-5cm; S2: Drying the slurry. Dry the slurry with a fluidity of 2-5 cm to a paste state. The fluidity loss of the slurry in the paste state is less than 3 mm within 30 minutes. S3: Granulation, using a granulator to granulate the slurry in a paste state to form nitrate-containing compound fertilizer particles; S4: coating, adding the coated diatomaceous earth to the nitrate-containing compound fertilizer particles and stirring, stirring and mixing for 30-40 minutes, and then drying the nitrate-containing compound fertilizer particles to form a coated nitrate-containing compound fertilizer.

2. The method for preparing a nitrate-containing composite fertilizer according to claim 1, wherein: The components by weight include 10 parts of nitrate, 3 parts of monoammonium phosphate, 3 parts of ammonium bicarbonate, 0.5 parts of urea, and 1 part of coated diatomaceous earth.

3. The method for preparing a nitrate-containing composite fertilizer according to claim 1, wherein: The components by weight include 12 parts of nitrate, 5 parts of monoammonium phosphate, 4 parts of ammonium bicarbonate, 1 part of urea, and 1.2 parts of coated diatomaceous earth.

4. The method for preparing a nitrate-containing composite fertilizer according to claim 1, wherein: The components by weight include 13 parts of nitrate, 8 parts of monoammonium phosphate, 5 parts of ammonium bicarbonate, 1.5 parts of urea, and 1.5 parts of coated diatomaceous earth.

5. The method for preparing a nitrate-containing composite fertilizer according to claim 1, wherein: The components by weight include 15 parts of nitrate, 10 parts of monoammonium phosphate, 8 parts of ammonium bicarbonate, 2 parts of urea, and 2 parts of coated diatomaceous earth.

6. The method for preparing a nitrate-containing compound fertilizer according to claim 1, wherein: The pressurization condition in S1 is 0.1-1 MPa, and the temperature in the pressure tank is 20-40 degrees Celsius.

7. The method for preparing a nitrate-containing compound fertilizer according to claim 1, wherein: The nitrate ions are taken from the polishing and cleaning wastewater in the aluminum industry.

8. The method for preparing a nitrate-containing compound fertilizer according to claim 1, wherein: In S4, the nitrate-containing compound fertilizer particles are dried to a moisture content of less than 30%.

9. The method for preparing a nitrate-containing composite fertilizer according to claim 1, wherein: The preparation method of the film-coated diatomite comprises the following steps: A1: Prepare materials, including diatomaceous earth, yellow mud and water. Grind the diatomaceous earth and yellow mud to form diatomaceous earth powder and yellow mud powder with a particle size of less than 0.002 mm. A2: To prepare coated diatomaceous earth, diatomaceous earth powder, yellow clay powder and water are mixed and stirred to form a slurry-like coated diatomaceous earth.

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