A compound organic fertilizer containing total water-soluble ammonium and a preparation method thereof

Abstract

The application discloses a kind of composite organic fertilizer containing full water-soluble monoammonium and preparation method thereof, belong to agricultural fertilizer technical field.The composite organic fertilizer includes organic matter seed particle, nutrient layer coated on the surface of organic matter seed particle and post-treatment layer coated on the surface of nutrient layer;Wherein, nutrient layer contains full water-soluble monoammonium premix consisting of monoammonium phosphate, oligomeric ammonium polyphosphate and solubility promoting active agent, and cooperate with potassium component, nitrogen-containing regulating component and water-soluble granulating adhesive component, post-treatment layer contains crystal control agent, anti-recrystallization auxiliary agent, hygroscopic buffer salt, lubricating dispersant and soluble film-forming auxiliary agent.By pre-preparing high water-soluble organic matter and microelement into seed particle, then build nutrient layer in several times and implement surface post-treatment, can reduce hygroscopic caking and local recrystallization, give consideration to particle strength, storage stability and rapid dissolution, low residue performance.

Description

Technical Field

[0001] This invention belongs to the field of agricultural fertilizer technology, specifically relating to a compound organic fertilizer containing fully water-soluble monoammonium phosphate and its preparation method. Background Technology

[0002] With the widespread application of fertilization methods such as fertigation, drip irrigation, and sprinkler irrigation, fertilizer products not only need to have high nutrient utilization rates but also need to exhibit characteristics such as rapid dissolution, low residue, and minimal clogging of fertilization equipment at the application end. Meanwhile, compound organic fertilizers also bear the responsibility of supplementing organic matter, providing synergistic nutrient supply, and improving application compatibility. Therefore, how to effectively combine highly soluble inorganic nutrients with organic components has become an important focus in the agricultural fertilizer field. Existing technologies indicate that the development of monoammonium phosphate or diammonium phosphate towards full water solubility can better meet the needs of water-saving agriculture and precision fertilization. However, related systems still generally suffer from problems such as high levels of insoluble raw materials, high conversion costs, and insufficient synergistic effects of nutrient components.

[0003] On the other hand, granular water-soluble fertilizers or compound fertilizers face multiple challenges in performance coordination during storage, transportation, and application. One type of problem is that increasing the degree of agglomeration or densification to improve granule strength often leads to a decrease in granule dissolution rate and an increase in water-insoluble matter. Another type of problem is that highly soluble salts are still prone to absorbing moisture, recrystallizing, and forming crystal bridges under low-moisture storage conditions, thus causing agglomeration, reduced fluidity, and inconvenience in use. In particular, the monoammonium phosphate system is prone to gradually forming agglomerated hard lumps from loose crystals or salt phase particles under humid and compressive conditions, which adversely affects storage, transportation, and application.

[0004] Invention CN108409394A discloses a fully water-soluble monoammonium phosphate (MAP) or diammonium phosphate (DAP) fertilizer and its preparation. It involves compounding crude MAP or DAP with ammonium polyphosphate and one or two of a solubilizing agent to improve the water solubility of the ammonium phosphate system and further introduce trace elements such as Zn, B, Mg, Mn, Mo, and Cu. This technology can improve the solubility of MAP or DAP and enhance fertilizer efficiency. However, this invention mainly focuses on the complete water solubility of ammonium phosphate itself and the compounding of trace elements. It does not specifically address the problems of hygroscopicity, agglomeration, recrystallization, and decreased particle dissolution rate that arise when highly water-soluble organic matter is compounded with fully water-soluble MAP in the same granular system.

[0005] Invention CN109650363B discloses a fully water-soluble anti-caking agent for industrial monoammonium phosphate and its application method. This method involves formulating an anti-caking system using a crystal control agent, lubricant, diluent, stabilizer, and moisture-proofing agent. After industrial monoammonium phosphate crystallizes, a post-treatment is performed by spraying the liquid component first, followed by the powder component, to reduce the tendency of monoammonium phosphate to caking during storage. This technology has a good effect on preventing the caking of industrial monoammonium phosphate crystals. However, this invention mainly targets crystallized industrial monoammonium phosphate, focusing on anti-caking treatment of the crystal surface. It is difficult to simultaneously consider the synergistic relationship between internal water migration, salt phase recrystallization, and rapid dissolution performance in compound fertilizer particles containing organic matter seed particles and multiple nutrient layering structures.

[0006] Invention CN121627446A discloses a water-soluble fertilizer for crops with varying growth periods and its preparation method. This method constructs a polyaspartic acid-metal-NPK core-shell composite intermediate and combines it with spray drying, spray granulation, and surface anti-caking treatment to balance the mechanical strength, rapid dissolution, and storage stability of the granular water-soluble fertilizer. This technology can improve the balance between strength and solubility in granular water-soluble fertilizer systems. However, this invention mainly focuses on inorganic nutrient core-shell intermediates and granular water-soluble fertilizers, and still lacks targeted solutions to the problems of hygroscopic sensitivity, interlayer recrystallization, and storage stability of compound organic fertilizers after the partial compounding of fully water-soluble monoammonium premixes and highly water-soluble organic matter.

[0007] Therefore, how to provide a compound organic fertilizer containing fully water-soluble monoammonium phosphate to solve or overcome the existing technical problems such as easy moisture absorption and clumping after compounding fully water-soluble phosphorus sources with highly water-soluble organic matter, poor granule storage stability, and difficulty in achieving both rapid dissolution and low residue is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0008] To address the shortcomings of the existing technology, this invention provides a fully water-soluble monoammonium compound organic fertilizer with good particle strength, which is not prone to clumping during storage, dissolves quickly upon application, and leaves low residue.

[0009] In a first aspect, the present invention provides a compound organic fertilizer containing fully water-soluble monoammonium phosphate, comprising organic matter seed particles, a nutrient layer coating the surface of the organic matter seed particles, and a post-treatment layer coating the surface of the nutrient layer; the organic matter seed particles account for 5-25% of the finished product mass, and the organic matter seed particles comprise a premixed component of highly water-soluble organic matter and trace elements; the post-treatment layer accounts for 0.25-0.8% of the finished product mass; the nutrient layer is composed of the organic matter seed particles and the post-treatment layer. The remainder, by mass, includes 35-70 parts of fully water-soluble monoammonium phosphate premix, 15-40 parts of potassium-containing component, 5-20 parts of nitrogen-containing regulating component, and 0.5-8 parts of water-soluble granulating binder component; the fully water-soluble monoammonium phosphate premix is ​​composed of monoammonium phosphate, oligomeric ammonium phosphate with an average degree of polymerization of 3-8, and a solubilizing agent, wherein the mass ratio of monoammonium phosphate to oligomeric ammonium phosphate is 2.5-6.0:1, and the amount of solubilizing agent is 1-6% of the total mass of monoammonium phosphate and oligomeric ammonium phosphate.

[0010] This invention pre-constructs highly water-soluble organic matter and trace elements into organic seed particles, then sets a nutrient layer mainly composed of a fully water-soluble monoammonium phosphate premix on the outside of these particles, and further sets a post-treatment layer on the outermost side, so that the organic phase and the highly soluble inorganic salt phase form a partitioned distribution structure inside the particles. This structure helps to reduce the direct large-area contact between highly water-soluble organic matter and fully water-soluble phosphate salts during storage, reducing the tendency for clumping and hardening caused by moisture absorption, local swelling, and salt phase recrystallization. On the other hand, by coating the organic seed particles with the nutrient layer, the fully water-soluble monoammonium phosphate-related nutrients can come into contact with water more quickly and be released when applied, thus taking into account the storage and transportation stability, application suitability, and good dissolution and dispersion performance of the granular fertilizer.

[0011] It should be noted that the use of a fully water-soluble monoammonium phosphate premix as the core phosphorus source unit in the nutrient layer in this invention is not merely for increasing phosphorus content. Rather, it addresses the fact that while monoammonium phosphate has high nutrient utilization value, conventional systems may still suffer from issues such as localized insoluble phases, insufficient dispersion, and inadequate stability when combined with other components. Therefore, this invention premixes monoammonium phosphate with oligomeric ammonium polyphosphate and a solubilizing agent, ensuring the phosphorus source is more easily dispersed and suitable for fertigation before entering the composite particle system. This provides a more stable material basis for subsequent compounding with organic matter and micronutrients, and mitigates the slow dissolution and insufficient application compatibility issues caused by high insoluble content in traditional monoammonium phosphate systems.

[0012] This invention pre-constructs highly water-soluble organic matter and trace elements into organic seed particles. This is not merely to meet the needs of the granulation process, but rather a structural design addressing problems such as moisture absorption, stickiness, segregation, and subsequent hardening that easily occur when highly water-soluble organic matter is directly mixed with highly soluble inorganic salts. If highly water-soluble organic matter is directly mixed with fully water-soluble monoammonium phosphate and other salt components for granulation, localized moisture accumulation can easily occur during particle formation and storage due to the relative sensitivity of the organic phase to moisture, further inducing salt phase re-precipitation and localized particle adhesion. This invention first pre-integrates the organic phase, making it a relatively stable nucleation base, and then constructs a nutrient layer on its outer surface. This helps reduce the degree of direct, large-area contact between highly water-soluble organic matter and high-salt components within the particles, improving the uniformity during the stratification granulation process and the structural stability during subsequent storage.

[0013] Furthermore, in the composite particle system of this invention, there is a natural interplay between particle strength, rapid dissolution, and anti-caking storage stability. On the one hand, simply increasing particle density or enhancing adhesion, while beneficial for improving particle strength, may lead to a decrease in particle wetting speed, a prolonged dissolution time, and an increase in residue. On the other hand, pursuing rapid dissolution at the expense of particle structural stability can result in increased powder shedding, breakage, and moisture absorption and clumping during storage and transportation. Therefore, this invention, through the partitioned arrangement of organic seed particles, an outer nutrient layer, and a post-treatment layer, allows the organic phase, the high-salt nutrient phase, and the surface control phase to each perform different functions, ensuring particle forming quality while mitigating the particle performance imbalance caused by interference between local components.

[0014] Preferably, the highly water-soluble organic matter includes at least two of the following: enzymatically hydrolyzed amino acids, potassium humate, seaweed extract, and molasses fermentation water-soluble organic matter.

[0015] When using the above technical solutions, enzymatically hydrolyzed amino acids, potassium humate, seaweed extracts, and molasses fermentation water-soluble organic matter are all easily dispersible or water-soluble organic matter sources. This ensures the introduction of organic matter while minimizing the problem of high residue levels associated with common, poorly soluble organic raw materials. The combination of different types of highly water-soluble organic matter to form the main body of the organic seed particles not only improves the wetting and dispersing properties of the particles during application but also enhances the compatibility between the organic and inorganic nutrient phases, thereby reducing phenomena such as salt precipitation, clumping, and uneven dissolution caused by incompatibility of local components.

[0016] Preferably, the trace element premixed component includes at least two of the following: zinc source, boron source, manganese source, molybdenum source, and copper source; the zinc source is zinc sulfate and / or amino acid chelated zinc, the boron source is boric acid and / or sodium tetraborate, the manganese source is manganese sulfate, the molybdenum source is sodium molybdate, and the copper source is amino acid chelated copper.

[0017] When employing the above technical solution, pre-incorporating micronutrients into the organic seed particles facilitates their dispersion and retention in the early stages of particle formation. This prevents their direct accumulation in localized high-concentration forms within the subsequent high-salt nutrient layer, thereby reducing the risk of localized unstable phases arising when some metal ions coexist with the phosphorus source. Furthermore, using sulfate, borate, molybdate, and amino acid-chelated copper and zinc forms can balance solubility, dispersibility, and compound stability, which is beneficial for improving the uniform nutrient release level of compound organic fertilizer under fertigation conditions.

[0018] Preferably, the potassium-containing component includes potassium nitrate and / or potassium dihydrogen phosphate, the nitrogen-containing regulating component includes urea and / or ammonium sulfate, and the water-soluble granulating binder component includes one or more of sodium lignin sulfonate, maltodextrin, and sodium polyglutamate.

[0019] Potassium nitrate, potassium dihydrogen phosphate, urea, and ammonium sulfate can all provide easily soluble potassium and nitrogen sources for the nutrient layer, enabling it to maintain a high nutrient density while still possessing good dispersibility in water. Water-soluble granulation binders play a role in particle surface adhesion, lamination, and strength regulation during nutrient layer construction, allowing the nutrient layer to stably coat the outer surface of organic seed particles, thereby reducing powder loss and segregation during granulation and improving particle formation quality without significantly increasing insoluble residue.

[0020] Preferably, the post-treatment layer comprises, by weight, 10-30 parts of crystal control agent, 5-25 parts of anti-recrystallization aid, 25-55 parts of moisture-absorbing buffer salt, 5-20 parts of lubricating dispersant, and 1-10 parts of soluble film-forming aid.

[0021] The post-treatment layer is not simply a moisture-proof or lubricating layer, but is specifically designed to address the characteristics of particle surfaces, such as easy hygroscopicity, easy recrystallization, and easy formation of crystal bridges. Crystal-controlling agents help disrupt the regular growth of surface crystals, anti-recrystallization aids help inhibit the redeposition and adhesion of salt phases after moisture absorption, moisture-absorbing buffer salts can mitigate the direct impact of environmental moisture fluctuations on the particle surface, and lubricating dispersants and soluble film-forming aids help improve the spreading uniformity and surface integrity of the post-treatment layer. This allows for improved storage dispersion and application flowability of composite particles even at relatively low addition levels.

[0022] In terms of material selection, this invention preferably uses organic matter sources that are easily soluble or dispersible in water, so that they can provide organic matter functions while minimizing the adverse effects of poorly soluble residues on application methods such as drip irrigation and sprinkler irrigation. The solubilizing agent used to form the fully water-soluble monoammonium phosphate premix is ​​preferably a water-soluble adjuvant that can improve the dispersibility of the phosphorus source without significantly increasing the content of insoluble matter in the system. The crystal control agent, anti-recrystallization aid, hygroscopic buffer salt, lubricating dispersant, and soluble film-forming aid in the post-treatment layer are preferably fully water-soluble or highly dispersible components, so as to improve the storage stability of the particle surface without introducing new sources of insoluble residues. Through the above-mentioned material boundary control, this invention can balance the matching relationship between organic matter introduction, nutrient layer construction, and rapid dissolution at the application end in the compound organic fertilizer system.

[0023] Preferably, the crystallization control agent includes one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate; the anti-recrystallization aid includes one or more of sodium citrate, sodium gluconate, and sodium hexametaphosphate; the hygroscopic buffer salt includes one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, and potassium carbonate; the lubricating dispersant includes one or more of fatty alcohol polyoxyethylene ether, sodium oleate, and polyoxyethylene octylphenol ether; and the soluble film-forming aid includes one or more of maltodextrin and sodium lignin sulfonate.

[0024] The various post-treatment components work synergistically. Surfactant crystallizers and lubricating dispersants improve the uniformity of the post-treatment layer's coverage on the particle surface. Anti-recrystallization aids such as sodium citrate, sodium gluconate, and sodium hexametaphosphate reduce the tendency for recrystallization caused by localized ion enrichment. Hygroscopic buffer salts such as anhydrous magnesium sulfate, anhydrous sodium sulfate, and potassium carbonate buffer surface moisture disturbances. Soluble film-forming aids such as maltodextrin and sodium lignin sulfonate enhance the adhesion and integrity of the post-treatment layer. This allows the particles to maintain good solubility while improving their anti-caking ability during storage.

[0025] Preferably, the organic seed particles have a particle size of 80-500 μm, the finished particles have a particle size of 1.5-4.0 mm, and the nutrient layer has a thickness of 50-600 μm.

[0026] Controlling the organic seed particle size within the range of 80-500μm facilitates its uniform dispersion as the core for particle formation within the granulation system, thus balancing the nucleation capacity of the seed particles with the uniformity of the subsequent nutrient layer coating. Controlling the finished particle size within the range of 1.5-4.0mm better meets the storage, transportation, and application requirements of conventional granular fertilizers. Controlling the nutrient layer thickness within the range of 50-600μm helps achieve a balance between particle strength, nutrient loading, and dissolution and dispersion rate, avoiding insufficient nutrient carrying capacity due to an excessively thin nutrient layer, or localized densification and decreased dissolution rate due to an excessively thick layer.

[0027] Secondly, the present invention also provides a method for preparing the compound organic fertilizer containing fully water-soluble monoammonium phosphate, comprising the following steps: S1. After mixing the highly water-soluble organic matter, the premixed components of medium and trace elements and the binder, the organic matter seed particles are obtained by one of spray drying, extrusion granulation or drum granulation, and the moisture content of the organic matter seed particles is controlled to be no higher than 5.0%. S2. Mix monoammonium phosphate, oligomeric ammonium polyphosphate and solubilizing agent to obtain a fully water-soluble monoammonium premix; S3. The fully water-soluble monoammonium premix, potassium-containing component, nitrogen-containing regulating component and water-soluble granulating binder are distributed into granulation liquid or mixed powder, and applied to the surface of the organic matter seed particles in a fluidized bed or rotary drum granulation equipment in multiple applications to form a nutrient layer, and at least one intermediate drying is performed during the multiple application process. S4. After drying and cooling the particles obtained in step S3, a liquid phase post-treatment agent containing a lubricating dispersant, a soluble film-forming aid, and a partial crystal control agent is first applied, followed by a powder phase post-treatment agent containing an anti-recrystallization aid, a moisture-absorbing buffer salt, and the remainder crystal control agent, to obtain the compound organic fertilizer containing fully water-soluble monoammonium phosphate.

[0028] Preferably, in step S1, the inlet air temperature of the spray drying is 110-170°C and the outlet air temperature is 55-90°C. In step S3, the material temperature of fluidized bed or rotary drum granulation is 40-75℃. When granulation liquid is used in step S3, the spraying pressure is 0.2-0.8MPa, the number of spraying times is 2-6, and after each spraying, intermediate drying is carried out at 40-70℃ for 2-15 minutes. After step S3, the particle moisture content is 1.0-4.0%.

[0029] Preferably, the liquid phase post-treatment agent is applied at a temperature of 30-50°C in step S4, and the powder phase post-treatment agent is added within 1-10 minutes after the liquid phase post-treatment agent is applied. The total amount of the post-treatment layer applied is 0.25-0.8% of the finished product mass, and the moisture content of the finished product is 0.5-3.0% after step S4.

[0030] The compound organic fertilizer containing fully water-soluble monoammonium phosphate and its preparation method provided by this invention have at least the following beneficial effects: (1) This invention constructs a partitioned composite particle structure consisting of organic seed particles, a nutrient layer, and a post-treatment layer, which enables highly water-soluble organic matter and trace elements to preferentially form a relatively stable core unit. The nutrient layer containing fully water-soluble monoammonium premix then loads nutrients on the outside, and the post-treatment layer further regulates the particle surface. This reduces the direct large-area contact between highly water-soluble organic matter and highly soluble phosphate salts inside the particles, and reduces the tendency to stickiness, clumping, and hardening caused by moisture absorption, local water enrichment, and salt phase recrystallization. At the same time, it facilitates faster wetting, dispersion, and nutrient release during application, and better balances particle storage stability and rapid dissolution performance.

[0031] (2) This invention specifically limits the types of highly water-soluble organic matter, the forms of trace elements, the nitrogen and potassium sources in the nutrient layer, the water-soluble granulation binder, and the crystal control agent, anti-recrystallization aid, moisture-absorbing buffer salt, lubricating dispersant, and soluble film-forming aid in the post-treatment layer, so that each component forms a synergistic relationship in terms of solubility, compound stability, and surface regulation function. Among them, the pre-integration of highly water-soluble organic matter and trace elements is beneficial to improving the compatibility of the system and reducing the risk of local salt precipitation. The water-soluble granulation binder is beneficial to improving the layering uniformity and particle forming quality during the construction of the nutrient layer. The post-treatment layer is beneficial to inhibiting the regular growth of crystals on the particle surface, reducing the tendency of recrystallization and crystal bridge formation after moisture absorption, thereby further improving the dispersion, flowability, and nutrient release uniformity of the particles during storage, transportation, and application.

[0032] (3) The preparation method provided by this invention adopts a process route of first preparing organic seed particles, then constructing nutrient layers in stages, and finally performing a surface post-treatment combining liquid and powder phases. This allows components with different properties to enter the particle system at more suitable stages, which helps to reduce the risk of moisture absorption and agglomeration and process fluctuations caused by highly water-soluble organic matter directly participating in granulation in the overall high-salt system. At the same time, by applying the nutrient layer in stages and drying it in between, the problems of local over-wetting, agglomeration, and uneven layer thickness caused by excessive one-time application can be mitigated. The post-treatment method of liquid phase first and then powder phase is conducive to improving the uniformity and integrity of the post-treatment layer on the particle surface. Therefore, the preparation method of this invention not only ensures the quality of particle forming, but also helps to improve the batch stability of products and the feasibility of industrial implementation. Detailed Implementation

[0033] To better understand the above technical solutions, a detailed description of the specific implementation methods will be provided below. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0035] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0036] This invention provides a compound organic fertilizer containing fully water-soluble monoammonium phosphate, which comprises a granular body and a surface conditioning component; wherein, the granular body includes, from the inside out, organic seed particles and a nutrient layer covering its surface, and a post-treatment layer is further provided on the outer side of the granular body, specifically including: (1) Organic seed particles, as the core part of the composite particles, are used to carry highly water-soluble organic matter and micronutrient premixed components, and provide a nucleation basis for the subsequent stratification of the nutrient layer. The organic seed particles account for 5-25% of the finished product mass, and their particle size is preferably 80-500 μm. The highly water-soluble organic matter in the organic seed particles may include at least two of the following: enzymatically hydrolyzed amino acids, potassium humate, seaweed extract, and molasses fermented water-soluble organic matter. The micronutrient premixed components may include at least two of the following: zinc source, boron source, manganese source, molybdenum source, and copper source. Preferably, the zinc source is zinc sulfate and / or amino acid chelated zinc, the boron source is boric acid and / or sodium tetraborate, the manganese source is manganese sulfate, the molybdenum source is sodium molybdate, and the copper source is amino acid chelated copper. By pre-integrating highly water-soluble organic matter and trace elements into seed particles, the problems of moisture absorption, segregation, and localized salt precipitation caused by direct mixing of highly water-soluble organic matter and high-salt nutrients in the early stage of overall granulation can be reduced, and the uniformity of particles in the subsequent stratification granulation process can be improved.

[0037] In one preferred embodiment, the highly water-soluble organic matter may be composed of 40-60 parts of enzymatically hydrolyzed amino acids, 15-30 parts of potassium humate, 5-15 parts of seaweed extract, and 5-20 parts of molasses fermented water-soluble organic matter by mass, and the amount of the micronutrient premixed component added is 0.5-10% of the total mass of the highly water-soluble organic matter.

[0038] In a more preferred embodiment, the enzymatically hydrolyzed amino acids are selected from powdered or granular materials with a total amino acid content of not less than 60%, the potassium humate is selected from powdered materials with a water solubility of not less than 95%, the seaweed extract is selected from dry powder with alginate, mannitol and natural soluble polysaccharides as the main active components, and the molasses fermentation water-soluble organic matter is selected from powdered materials with a moisture content of not more than 10% after concentration and drying. By selecting the above materials, the tendency of seed particles to absorb moisture and clump together during storage and transportation can be further reduced.

[0039] (2) Nutrient layer, covering the outer side of the organic seed particles, is used to supply the main inorganic nutrients in the composite particles and to regulate the particle forming quality and dissolution and dispersion properties during application. The nutrient layer is the remainder excluding the organic seed particles and the post-treatment layer, and by mass, it includes 35-70 parts of fully water-soluble monoammonium phosphate premix, 15-40 parts of potassium-containing component, 5-20 parts of nitrogen-containing regulating component, and 0.5-8 parts of water-soluble granulating binder component. The fully water-soluble monoammonium phosphate premix is ​​composed of monoammonium phosphate, oligomeric ammonium phosphate with an average degree of polymerization of 3-8, and a solubilizing agent. The mass ratio of monoammonium phosphate to oligomeric ammonium phosphate is 2.5-6.0:1, and the amount of solubilizing agent is 1-6% of the total mass of monoammonium phosphate and oligomeric ammonium phosphate. The potassium-containing component may include potassium nitrate and / or potassium dihydrogen phosphate, the nitrogen-containing regulating component may include urea and / or ammonium sulfate, and the water-soluble granulating binder may include one or more of sodium lignosulfonate, maltodextrin, and sodium polyglutamate. With the above configuration, the nutrient layer can maintain a high nutrient density while improving the stratification and adhesion to the seed particle surface, and facilitates faster wetting and dissolution at the application end.

[0040] In one preferred embodiment, the solubilizing agent is one or more of organophosphonate solubilizing agents, water-soluble polyamine phosphonate solubilizing agents, and lignin sulfonate dispersing agents. Its function is to improve the dispersion stability of monoammonium phosphate and oligomeric ammonium polyphosphate after compounding, and to reduce the tendency of local crystallization when compounded with nitrogen and potassium salts in the future.

[0041] In a more preferred embodiment, the nutrient layer contains 40-60 parts of a fully water-soluble monoammonium premix, 18-32 parts of a potassium-containing component, 6-15 parts of a nitrogen-containing adjusting component, and 1-5 parts of a water-soluble granulating binder component; the thickness of the nutrient layer is preferably 50-600 μm, and the particle size of the finished product is preferably 1.5-4.0 mm. Within this range, sufficient nutrient loading capacity of the nutrient layer can be ensured, while avoiding the problems of local densification and slow dissolution caused by excessive layer thickness.

[0042] In one preferred embodiment, the water-soluble granulating binder, in addition to its granulation function, can also serve as a dispersing auxiliary phase within the nutrient layer, allowing the high-salt inorganic nutrient components to adhere more evenly to the surface of the seed particles during the stratification process, thereby reducing localized powder shedding, particle eccentricity, or uneven layer thickness during the primary granulation process.

[0043] (3) A post-treatment layer, covering the surface of the nutrient layer, is used to regulate the moisture absorption, recrystallization, crystal bridge formation, and storage flowability of the particle surface. The post-treatment layer accounts for 0.25-0.8% of the finished product mass and includes, by mass, 10-30 parts of crystal control agent, 5-25 parts of anti-recrystallization aid, 25-55 parts of moisture-absorbing buffer salt, 5-20 parts of lubricating dispersant, and 1-10 parts of soluble film-forming aid. Among them, the crystal control agent may include one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate; the anti-recrystallization aid may include one or more of sodium citrate, sodium gluconate, and sodium hexametaphosphate; the moisture-absorbing buffer salt may include one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, and potassium carbonate; the lubricating dispersant may include one or more of fatty alcohol polyoxyethylene ether, sodium oleate, and polyoxyethylene octylphenol ether; and the soluble film-forming aid may include one or more of maltodextrin and sodium lignin sulfonate. By setting up the above post-treatment layer, the local ion concentration and recrystallization phenomenon caused by the high salt content of fully water-soluble monoammonium phosphate on the particle surface after it becomes damp can be reduced, and the dispersion and storage fluidity of the particle surface can be improved.

[0044] In one preferred embodiment, the crystal control agent and lubricating dispersant in the post-treatment layer are first applied to the surface of the nutrient layer in a liquid phase to form an initial spreading layer on the particle surface. Subsequently, a powder phase component containing an anti-recrystallization aid, a moisture-absorbing buffer salt, and the remaining crystal control agent is applied to improve the coverage uniformity and integrity of the surface treatment layer.

[0045] In a more preferred embodiment, the post-treatment layer contains 30-50 parts of hygroscopic buffer salt, 8-20 parts of anti-recrystallization aid, and 2-8 parts of soluble film-forming aid, in order to further improve the anti-caking ability of the particles while maintaining rapid wetting and low residue.

[0046] The preparation method of the above-mentioned compound organic fertilizer containing fully water-soluble monoammonium phosphate specifically includes the following steps: S1. Preparation of Organic Seed Particles: High water-soluble organic matter, a premixed component of trace elements, and a binder are mixed and then processed using one of the following methods: spray drying, extrusion granulation, or drum granulation. The moisture content of the organic seed particles is controlled to be no higher than 5.0%. Specifically, when using spray drying, the high water-soluble organic matter and the premixed component of trace elements are first dispersed in deionized water to form a slurry with a solid content of 20-50%, and then the binder is added to adjust the slurry viscosity to a range suitable for atomization. Preferably, the inlet air temperature of the spray dryer is 110-170℃, and the outlet air temperature is 55-90℃. When using extrusion granulation, the high water-soluble organic matter and the premixed component of trace elements are first dry-mixed evenly, and then the binder is sprayed in and granulated under low-speed mixing conditions to form nuclei. When using drum granulation, seed particles with a particle size of 80-500 μm can be formed by continuous spraying and rolling.

[0047] In one preferred embodiment, the binder may be one or more of sodium lignosulfonate aqueous solution, maltodextrin aqueous solution, and sodium polyglutamate aqueous solution, with a solid content of 5-30%, and the amount added is 2-20% of the total mass of the premixed components of highly water-soluble organic matter and trace elements. By controlling the binder within the above range, both nucleation efficiency and drying and dehydration efficiency can be achieved.

[0048] In a more preferred embodiment, the organic seed particles are temporarily stored under conditions where the relative humidity is not higher than 50% after preparation, and then enter the subsequent nutrient layer construction step within 24 hours to further reduce the risk of clumping due to moisture absorption.

[0049] S2. Preparation of the fully water-soluble monoammonium phosphate premix: Monoammonium phosphate, oligomeric ammonium polyphosphate, and a solubilizing agent are mixed in a predetermined ratio to obtain the fully water-soluble monoammonium phosphate premix. Specifically, a horizontal ribbon mixer, a twin-shaft paddle mixer, or a high-speed mixer can be used for dry mixing. Alternatively, the solubilizing agent can be pre-dissolved in a small amount of water and then atomized and sprayed into the mixed powder of monoammonium phosphate and oligomeric ammonium polyphosphate for wetting and mixing, followed by low-temperature drying to obtain a premix with good flowability.

[0050] In one preferred embodiment, the monoammonium phosphate has a particle size of 80-500 μm, the oligomeric ammonium phosphate has a particle size of 50-300 μm, and the solubilizing activator is added at a ratio of 1-6% of the total mass of the monoammonium phosphate and the oligomeric ammonium phosphate. By controlling the particle sizes of each component within a similar range, it is beneficial to improve the premixing uniformity and reduce stratification.

[0051] In a more preferred embodiment, the water content of the fully water-soluble monoammonium premix is ​​controlled to be no higher than 3.0% after preparation, so as to avoid premature clumping or local hardening during the subsequent nutrient layer construction process.

[0052] S3. Construction of the nutrient layer: The fully water-soluble monoammonium phosphate premix, potassium-containing component, nitrogen-containing regulating component, and water-soluble granulating binder are prepared into a granulation slurry or mixed powder, and applied in stages to the surface of the organic seed particles in a fluidized bed or rotary drum granulation device to form a nutrient layer, with at least one intermediate drying during the staged application. Preferably, the material temperature in step S3 of fluidized bed or rotary drum granulation is 40-75℃; when using a granulation slurry, the spraying pressure is 0.2-0.8MPa; the number of spraying stages is 2-6; after each spraying, intermediate drying is carried out at 40-70℃ for 2-15 minutes; after step S3, the particle moisture content is 1.0-4.0%. When using granulation liquid, the fully water-soluble monoammonium premix, a portion of potassium-containing components, a portion of nitrogen-containing regulating components, and water-soluble granulating binder components can be added to water to prepare a liquid with a solid content of 20-60%. The liquid is then applied to the surface of the seed particles in multiple applications by atomization spraying. When using mixed powder, the above components can be dry-mixed evenly and then coated onto the surface of the seed particles with a small amount of atomized water or low-concentration binder by roller coating.

[0053] In one preferred embodiment, the amount applied in the first two applications during the multi-application process can be controlled to be 20-40% of the total amount applied, the amount applied in the middle applications can be controlled to be 40-60% of the total amount applied, and the amount applied in the last application can be controlled to be 10-30% of the total amount applied, so as to gradually thicken the nutrient layer and reduce local over-wetting and agglomeration caused by excessive feeding at one time.

[0054] In a more preferred embodiment, after the nutrient layer is constructed, it can be screened to remove particles that are too large or too small, and then qualified particles can be put into the post-processing step to improve the consistency of particle size distribution in the finished product.

[0055] S4. Application of the post-treatment layer: After drying and cooling the particles obtained in step S3, a liquid-phase post-treatment agent containing a lubricating dispersant, a soluble film-forming aid, and a portion of a crystal-controlling agent is first applied, followed by a powder-phase post-treatment agent containing an anti-recrystallization aid, a moisture-absorbing buffer salt, and the remainder of a crystal-controlling agent, to obtain the compound organic fertilizer containing fully water-soluble monoammonium phosphate. Preferably, the application temperature of the liquid-phase post-treatment agent in step S4 is 30-50℃, and the powder-phase post-treatment agent is added within 1-10 minutes after the application of the liquid-phase post-treatment agent. The total amount of the post-treatment layer applied is 0.25-0.8% of the finished product mass, and the moisture content of the finished product after step S4 is 0.5-3.0%. The liquid-phase post-treatment agent can be applied uniformly to the particle surface by spraying to form an initial wetted and spreadable layer on the particle surface; subsequently, the powder-phase post-treatment agent is added and uniformly adhered through roller turning or fluidization.

[0056] In one preferred embodiment, the total solid content of the lubricating dispersant and soluble film-forming aid in the liquid phase post-treatment agent is 5-30%, and the average particle size of the powder phase post-treatment agent is 20-200 μm. By controlling the morphology and particle size of the liquid and powder phase components, the spreading integrity of the post-treatment layer can be further improved.

[0057] In a more preferred embodiment, after step S4 is completed, the finished granules are left to stand at room temperature for 2-24 hours to allow the post-treatment layer to settle further and become more uniform before packaging, thereby improving the surface stability of the finished product during storage and transportation.

[0058] Example 1 This embodiment provides a compound organic fertilizer containing fully water-soluble monoammonium phosphate, with a total finished product weight of 100.0 kg.

[0059] 1. Material Composition (1) 15.0 kg of solid material for organic seed granules, including: 7.70 kg of enzymatically hydrolyzed amino acids, 3.00 kg of potassium humate, 1.40 kg of seaweed extract, 1.40 kg of molasses fermented water-soluble organic matter, 0.48 kg of zinc sulfate, 0.18 kg of boric acid, 0.12 kg of manganese sulfate, 0.04 kg of sodium molybdate, 0.03 kg of amino acid chelated copper, and 0.65 kg of sodium lignin sulfonate.

[0060] (2) 84.5 kg of materials for the nutrient layer, including: 48.0 kg of water-soluble monoammonium premix, 14.0 kg of potassium nitrate, 10.0 kg of potassium dihydrogen phosphate, 6.0 kg of urea, 4.0 kg of ammonium sulfate, 1.5 kg of sodium lignosulfonate, 0.6 kg of maltodextrin, and 0.4 kg of sodium polyglutamate.

[0061] The 48.0 kg of fully water-soluble monoammonium premix consists of 37.0 kg of monoammonium phosphate, 9.25 kg of oligomeric ammonium polyphosphate with an average degree of polymerization of 5, and 1.75 kg of solubilizing activator.

[0062] (3) 0.50 kg of materials for the post-treatment layer, including: 0.08 kg of sodium dodecyl sulfonate, 0.04 kg of sodium dodecylbenzene sulfonate, 0.03 kg of sodium citrate, 0.02 kg of sodium gluconate, 0.02 kg of sodium hexametaphosphate, 0.10 kg of anhydrous magnesium sulfate, 0.07 kg of anhydrous sodium sulfate, 0.05 kg of potassium carbonate, 0.025 kg of fatty alcohol polyoxyethylene ether, 0.015 kg of sodium oleate, 0.03 kg of maltodextrin, and 0.02 kg of sodium lignin sulfonate.

[0063] 2. Preparation method S1. Enzymatically hydrolyzed amino acids, potassium humate, seaweed extract, molasses fermentation water-soluble organic matter, zinc sulfate, boric acid, manganese sulfate, sodium molybdate, amino acid chelated copper, and sodium lignosulfonate were added to 18.0 kg of deionized water and stirred at 800 rpm for 20 min at 45 °C to form a uniform slurry. Subsequently, organic seed particles were prepared by spray drying. The spray drying inlet air temperature was 145 °C, the outlet air temperature was 72 °C, and the atomization pressure was 0.55 MPa. Particles with a diameter of 80-500 μm were collected to obtain 15.0 kg of organic seed particles with a moisture content of 4.1%.

[0064] S2. Add monoammonium phosphate, oligomeric ammonium polyphosphate and solubilizing agent to a horizontal ribbon mixer and mix for 15 min to obtain 48.0 kg of fully water-soluble monoammonium premix.

[0065] S3. Mix the fully water-soluble monoammonium phosphate premix, potassium nitrate, potassium dihydrogen phosphate, urea, ammonium sulfate, sodium lignosulfonate, maltodextrin, and sodium polyglutamate evenly to obtain 84.5 kg of nutrient layer mixed powder. Place the organic seed particles obtained in S1 into a rotary drum granulator, control the material temperature at 58℃, and apply the nutrient layer mixed powder to the surface of the organic seed particles in four stages. After each application, spray an appropriate amount of deionized water to wet the surface, and simultaneously dry it at 60℃ for 8 minutes. After the four applications are completed, dry at 70℃ until the particle moisture content is 2.2%, cool to 28℃, and sieve to obtain nutrient layer particles with a particle size of 1.5-4.0 mm.

[0066] S4. Dissolve fatty alcohol polyoxyethylene ether, sodium oleate, maltodextrin, sodium lignin sulfonate, and a portion of sodium dodecyl sulfonate and sodium dodecylbenzene sulfonate in 1.2 kg of deionized water to prepare a liquid post-treatment agent. Spray the liquid onto the surface of the granules obtained in S3 at 35°C. After spraying for 5 min, add the remaining powder post-treatment agent, consisting of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium citrate, sodium gluconate, sodium hexametaphosphate, anhydrous magnesium sulfate, anhydrous sodium sulfate, and potassium carbonate, and mix evenly for 10 min. Then, mature the mixture at 40°C for 2 h to obtain 100.0 kg of finished compound organic fertilizer with a moisture content of 1.6%.

[0067] Example 2 The difference between this embodiment and Example 1 is that only two types of highly water-soluble organic matter are used in the organic seed particles: 10.10 kg of enzymatically hydrolyzed amino acids, 4.00 kg of potassium humate, 0.48 kg of zinc sulfate, 0.18 kg of boric acid, 0.12 kg of manganese sulfate, 0.04 kg of sodium molybdate, 0.03 kg of amino acid chelated copper, and 0.05 kg of sodium lignin sulfonate. The remaining components remain the same. The preparation method is the same as in Example 1.

[0068] Example 3 The difference between this embodiment and Example 1 is that the micronutrient premixed components only use zinc and boron sources, specifically: 0.55 kg of zinc sulfate and 0.25 kg of boric acid. The composition of the remaining highly water-soluble organic matter, nutrient layer, and post-treatment layer is the same as in Example 1, and the rest of the preparation methods remain the same.

[0069] Example 4 The difference between this embodiment and Embodiment 1 is that the organic seed particles account for 5.0% of the finished product mass. Specifically, the total amount of organic seed particles is 5.0 kg, the total amount of the nutrient layer is 94.5 kg, and the total amount of the post-treatment layer is 0.50 kg; the proportions of each component inside the organic seed particles and the nutrient layer are the same as in Embodiment 1, and the remaining preparation methods are consistent.

[0070] Example 5 The difference between this embodiment and Embodiment 1 is that the organic seed particles account for 25.0% of the finished product mass. Specifically, the total amount of organic seed particles is 25.0 kg, the total amount of the nutrient layer is 74.5 kg, and the total amount of the post-treatment layer is 0.50 kg; the proportions of each component inside the organic seed particles and the nutrient layer are the same as in Embodiment 1, and the remaining preparation methods are consistent.

[0071] Example 6 The difference between this embodiment and Example 1 is that the mass ratio of monoammonium phosphate to ammonium oligophosphate in the fully water-soluble monoammonium premix is ​​2.5:1, and the amount of solubilizing agent is 6.0% of the total mass of monoammonium phosphate and ammonium oligophosphate. Specifically, the 48.0 kg of fully water-soluble monoammonium premix in Example 1 is adjusted to: 32.94 kg of monoammonium phosphate, 13.18 kg of ammonium oligophosphate, and 1.88 kg of solubilizing agent, while the rest remains the same.

[0072] Example 7 The difference between this embodiment and Example 1 is that the mass ratio of monoammonium phosphate to ammonium oligophosphate in the fully water-soluble monoammonium premix is ​​6.0:1, and the amount of solubilizing agent is 1.0% of the total mass of monoammonium phosphate and ammonium oligophosphate. Specifically, the 48.0 kg of fully water-soluble monoammonium premix in Example 1 is adjusted to: 40.88 kg of monoammonium phosphate, 6.81 kg of ammonium oligophosphate, and 0.31 kg of solubilizing agent, while the rest remains the same.

[0073] Example 8 The difference between this embodiment and Embodiment 1 is that the total amount of the post-treatment layer applied is 0.25% of the finished product mass. Specifically, the total amount of the post-treatment layer is 0.25 kg, the distribution ratio of each component of the liquid phase and the powder phase is the same as in Embodiment 1, and the rest remains the same.

[0074] Example 9 The difference between this embodiment and Embodiment 1 is that the total amount of the post-treatment layer applied is 0.80% of the finished product mass. Specifically, the total amount of the post-treatment layer is 0.80 kg, the distribution ratio of each component of the liquid phase and the powder phase is the same as in Embodiment 1, and the rest remains the same.

[0075] Example 10 The difference between this embodiment and Embodiment 1 is that the nutrient layer in step S3 is constructed by roller coating with a mixed powder. Specifically, the fully water-soluble monoammonium phosphate premix, potassium-containing component, nitrogen-containing regulating component, and water-soluble granulating binder are first dry-mixed evenly, and then applied to the surface of organic seed particles in six batches in a rotary drum granulator. After each application, atomized deionized water is sprayed in, with a total spray volume of 10.0 wt% of the nutrient layer mixed powder. After each application, the mixture is dried at 55°C for 10 minutes, while the rest remains consistent.

[0076] Comparative Example 1 The difference between this comparative example and Example 1 is that organic seed granules are not prepared, nor are nutrient layers and post-treatment layers constructed. Instead, all solid materials from Example 1 are mixed at once and then directly granulated using conventional rotary drum granulation to obtain a whole blended granular fertilizer. The remaining processes remain the same.

[0077] Comparative Example 2 The difference between this comparative example and Example 1 is that no post-processing layer is provided. Specifically, after completing S3, Example 1 proceeds directly to drying, cooling, and packaging, while the rest remains the same.

[0078] Comparative Example 3 The difference between this comparative example and Example 1 is that 48.0 kg of ordinary monoammonium phosphate is used to directly replace 48.0 kg of the fully water-soluble monoammonium phosphate premix, and no oligomeric polyphosphate ammonium or solubilizing activator is added, while the rest remains the same.

[0079] Comparative Example 4 The difference between this comparative example and Example 1 is that no solubilizing agent was added to the fully water-soluble monoammonium phosphate premix. Specifically, only monoammonium phosphate and oligomeric ammonium polyphosphate were mixed according to the mass ratio of Example 1 to obtain the premix, while the rest remained the same.

[0080] Comparative Example 5 The difference between this comparative example and Example 1 is that step S3 does not involve multiple applications and intermediate drying. Instead, all the nutrient layer material is added to the surface of the organic seed particles at once, followed by direct granulation and final drying. The rest remains the same.

[0081] Comparative Example 6 This comparative example differs from Example 1 in that no water-soluble granulating binder is added. Specifically, sodium lignosulfonate, maltodextrin, and sodium polyglutamate in the nutrient layer of Example 1 are all removed, while the rest remain the same.

[0082] Test methods 1. Solubility (complete dissolution time / s): Refer to NY / T 1973-2021 Determination of water-insoluble matter content and pH of water-soluble fertilizers. Weigh 100.0g of sample and add it to 1000mL of deionized water. Stir magnetically at 300rpm at 25±2℃ and record the time required from the addition of the sample to when no visible particles remain.

[0083] 2. Complete solubility (water-insoluble matter / wt%): Refer to NY / T 1973-2021 Determination of water-insoluble matter content and pH of water-soluble fertilizers. After completing the above solubility test, filter the solution, collect the filter residue, and dry it at 105℃ to constant weight. Calculate the water-insoluble matter content as a percentage of the filter residue mass to the sample mass.

[0084] 3. Mechanical strength (single-particle compressive strength / N): Single-particle compression method was used. Thirty particles with a particle size within the range of D50±10% were randomly selected and subjected to single-particle compression test using a texture analyzer. The probe diameter was 10mm, the compression speed was 1.0mm / s, and the trigger force was 0.05N. The peak force at the moment of particle breakage was recorded and the average value was taken.

[0085] 4. Anti-caking property (caking rate / %): Refer to GB / T 33425-2016 Evaluation method for anti-caking performance of anti-caking agents in chemical products. After storing the sample under specified humid heat and pressure conditions for a certain period of time, it is gently turned over and sieved. The percentage of the mass of the caking part to the total mass of the sample is counted as the caking rate.

[0086] 5. Process stability (qualified particle rate / %): Sieving method is used. The obtained particles are sieved through 1.5mm and 4.0mm sieves, and the percentage of particles with a particle size in the range of 1.5-4.0mm is counted as the qualified particle rate.

[0087] Test Results The test results of Examples 1-10 and Comparative Examples 1-6 are shown in Table 1: Table 1

[0088] As can be seen from Table 1, Examples 1-10 are generally superior to Comparative Examples 1-6, indicating that the "organic seed particles - nutrient layer - post-treatment layer" partitioned composite particle structure, fully water-soluble monoammonium premix, phased application combined with intermediate drying and post-treatment layer design adopted in this case can achieve a good comprehensive balance between rapid dissolution, low residue, particle strength and anti-caking.

[0089] Regarding the core structure of the product, compared with Comparative Example 1, the complete dissolution time of Example 1 decreased from 320s to 190s, the water-insoluble matter decreased from 0.58wt% to 0.23wt%, the agglomeration rate decreased from 18.5% to 3.8%, and the single-particle compressive strength increased from 7.1N to 10.8N. This indicates that simple one-time mixing and granulation is difficult to achieve the synergy between the organic matter system and the high-salt nutrient system. However, by adopting a partitioned composite particle structure, the solubility, storage stability and mechanical strength of the particles can be significantly improved.

[0090] Regarding the fully water-soluble monoammonium phosphate premix, Comparative Examples 3 and 4 eliminated the fully water-soluble monoammonium phosphate premix or the solubilizing agent, respectively. The complete dissolution time and water-insoluble matter were significantly worse, indicating that when ordinary monoammonium phosphate is directly introduced into the system, it is more likely to cause local poorly soluble phases and uneven dissolution problems. The introduction of oligomeric polyphosphate and solubilizing agent helps to improve the dispersion and dissolution state of phosphorus source in composite particles.

[0091] Regarding the post-treatment layer, Examples 8 and 9 correspond to low and high values ​​of post-treatment layer addition, respectively. It can be seen that when the post-treatment layer content is increased from 0.25% to 0.80%, the agglomeration rate can be further reduced from 6.9% to 2.6%, but the complete dissolution time increases slightly. This indicates that when the post-treatment layer addition is too low, the surface protection effect is limited, while appropriately increasing the post-treatment amount is more beneficial for improving storage anti-agglomeration properties.

[0092] Comparing the examples internally, Examples 4 and 5 correspond to the lower and upper limits of the proportion of organic matter seed particles, respectively. Example 4 exhibits better solubility, while Example 5, although slightly stronger, shows a decrease in dissolution rate and water-insoluble matter level. This indicates that an excessively high proportion of organic matter seed particles increases the organic phase ratio and hygroscopic sensitivity of the system, thus hindering rapid and complete dissolution. Conversely, while a low proportion of seed particles results in better solubility, it relatively weakens the role of organic matter in functional and structural partitioning. Overall, the intermediate range near Example 1 is more conducive to achieving balanced performance.

[0093] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Clearly, those skilled in the art can make various alterations and variations to the invention without departing from its spirit and scope. Therefore, if these modifications and variations of the invention fall within the scope of the invention and its equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A compound organic fertilizer containing fully water-soluble monoammonium phosphate, characterized in that, It includes organic seed particles, a nutrient layer covering the surface of the organic seed particles, and a post-treatment layer covering the surface of the nutrient layer; The organic seed particles account for 5-25% of the finished product mass, and the organic seed particles include a premixed component of highly water-soluble organic matter and trace elements. The post-processing layer accounts for 0.25-0.8% of the finished product's mass; The nutrient layer is the remainder excluding the organic seed particles and the post-treatment layer, and by mass, it includes 35-70 parts of fully water-soluble monoammonium premix, 15-40 parts of potassium-containing components, 5-20 parts of nitrogen-containing regulating components, and 0.5-8 parts of water-soluble granulation and binding components. The fully water-soluble monoammonium phosphate premix is ​​composed of monoammonium phosphate, oligomeric ammonium phosphate with an average degree of polymerization of 3-8, and a solubilizing agent. The mass ratio of monoammonium phosphate to oligomeric ammonium phosphate is (2.5-6.0):1, and the amount of solubilizing agent is 1-6% of the total mass of monoammonium phosphate and oligomeric ammonium phosphate.

2. The compound organic fertilizer containing fully water-soluble monoammonium as described in claim 1, characterized in that, The highly water-soluble organic matter includes at least two of the following: enzymatically hydrolyzed amino acids, potassium humate, seaweed extract, and molasses fermentation water-soluble organic matter.

3. The compound organic fertilizer containing fully water-soluble monoammonium as described in claim 1, characterized in that, The micronutrient premixed components include at least two of the following: zinc source, boron source, manganese source, molybdenum source, and copper source; the zinc source is zinc sulfate and / or amino acid chelated zinc, the boron source is boric acid and / or sodium tetraborate, the manganese source is manganese sulfate, the molybdenum source is sodium molybdate, and the copper source is amino acid chelated copper.

4. The compound organic fertilizer containing fully water-soluble monoammonium as described in claim 1, characterized in that, The potassium-containing component includes potassium nitrate and / or potassium dihydrogen phosphate, the nitrogen-containing regulating component includes urea and / or ammonium sulfate, and the water-soluble granulating binder component includes one or more of sodium lignin sulfonate, maltodextrin, and sodium polyglutamate.

5. The compound organic fertilizer containing fully water-soluble monoammonium as described in claim 1, characterized in that, The post-treatment layer, by weight, comprises 10-30 parts of crystal control agent, 5-25 parts of anti-recrystallization aid, 25-55 parts of moisture-absorbing buffer salt, 5-20 parts of lubricating dispersant, and 1-10 parts of soluble film-forming aid.

6. The compound organic fertilizer containing fully water-soluble monoammonium as described in claim 5, characterized in that, The crystal control agent includes one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate. The anti-recrystallization aid includes one or more of sodium citrate, sodium gluconate, and sodium hexametaphosphate, and the hygroscopic buffer salt includes one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, and potassium carbonate. The lubricating dispersant includes one or more of fatty alcohol polyoxyethylene ether, sodium oleate, and polyoxyethylene octylphenol ether; The soluble film-forming aid includes one or more of maltodextrin and sodium lignin sulfonate.

7. The compound organic fertilizer containing fully water-soluble monoammonium as described in claim 1, characterized in that, The organic seed particles have a particle size of 80-500 μm, the finished particles have a particle size of 1.5-4.0 mm, and the nutrient layer has a thickness of 50-600 μm.

8. A method for preparing a compound organic fertilizer containing fully water-soluble monoammonium as described in any one of claims 1-7, characterized in that, The steps include the following: S1. After mixing the highly water-soluble organic matter, the premixed components of medium and trace elements and the binder, the organic matter seed particles are obtained by one of spray drying, extrusion granulation or drum granulation, and the moisture content of the organic matter seed particles is controlled to be no higher than 5.0%. S2. Mix monoammonium phosphate, oligomeric ammonium polyphosphate and solubilizing agent to obtain a fully water-soluble monoammonium premix; S3. The fully water-soluble monoammonium premix, potassium-containing component, nitrogen-containing regulating component and water-soluble granulating binder are distributed into granulation liquid or mixed powder, and applied to the surface of the organic matter seed particles in a fluidized bed or rotary drum granulation equipment in multiple applications to form a nutrient layer, and at least one intermediate drying is performed during the multiple application process. S4. After drying and cooling the particles obtained in step S3, a liquid phase post-treatment agent containing a lubricating dispersant, a soluble film-forming aid, and a partial crystal control agent is first applied, followed by a powder phase post-treatment agent containing an anti-recrystallization aid, a moisture-absorbing buffer salt, and the remainder crystal control agent, to obtain the compound organic fertilizer containing fully water-soluble monoammonium phosphate.

9. The preparation method according to claim 8, characterized in that, In step S1, the inlet air temperature for spray drying is 110-170℃ and the outlet air temperature is 55-90℃. In step S3, the material temperature of fluidized bed or rotary drum granulation is 40-75℃. When granulation liquid is used in step S3, the spraying pressure is 0.2-0.8MPa, the number of spraying times is 2-6, and after each spraying, intermediate drying is carried out at 40-70℃ for 2-15 minutes. After step S3, the particle moisture content is 1.0-4.0%.

10. The preparation method according to claim 8, characterized in that, In step S4, the liquid phase post-treatment agent is applied at a temperature of 30-50°C, and the powder phase post-treatment agent is added within 1-10 minutes after the liquid phase post-treatment agent is applied. The total amount of the post-treatment layer applied is 0.25-0.8% of the finished product mass. After step S4, the moisture content of the finished product is 0.5-3.0%.

Images