Production method of high-performance monoammonium phosphate

Abstract

The invention belongs to the field of chemical industry, and discloses a high-performance monoammonium phosphate production method, which comprises: S1, raw material pretreatment: carrying out pretreatment on phosphate ore and ammonia gas to remove impurities; the pretreated phosphate ore reacts with sulfuric acid to generate phosphoric acid, then the phosphoric acid reacts with ammonia gas to generate monoammonium phosphate, the reaction temperature of the phosphate ore and the sulfuric acid is 80-100 DEG C, the reaction time is 2-6 hours, and the concentration of the phosphoric acid is 0.2 mol.L <-1 >-2 mol.L <-1 >; s3, crystallization: cooling and crystallizing to obtain monoammonium phosphate crystals; s4, separation: separating the monoammonium phosphate crystals from the mother liquor; s5, drying: carrying out drying treatment on the separated monoammonium phosphate crystals; and S6, packaging: packaging the dried monoammonium phosphate to obtain a finished product. According to the invention, the purity and production efficiency of monoammonium phosphate are greatly improved, the production process flow is reduced, and the energy consumption and environmental pollution are reduced.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a method for producing high-performance monoammonium phosphate. Background Art

[0002] Monoammonium phosphate is a water-soluble quick-acting compound fertilizer, which is widely applicable to various food crops and cash crops such as rice, wheat, corn, sorghum, cotton, fruits, vegetables, etc. The traditional production method of monoammonium phosphate has the problems of high energy consumption, serious pollution, low product purity, etc., which is difficult to meet the needs of modern agriculture and industry. The present invention provides a novel production method of monoammonium phosphate, aiming to solve the above problems in the prior art. Summary of the invention

[0003] The purpose of the present invention is to provide a method for producing high-performance monoammonium phosphate, which can effectively solve the technical problems mentioned in the background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions: A method for producing high-performance monoammonium phosphate comprises the following steps: S1. Raw material pretreatment: pretreat phosphate rock and ammonia to remove impurities; S11. Pretreatment of phosphate rock: Crushing and screening: The phosphate ore is crushed coarsely and finely through a crusher to make its particle size reach the required range, and the ore is classified into different particle sizes using screening equipment; Washing and desludging: Remove dirt and sand from the surface of phosphate ore by water washing or wet screening; Magnetic separation and flotation: Use magnetic separators to remove iron impurities from phosphate ore; Drying and storage: The treated phosphate rock is dried to remove excess moisture and should be stored in a dry, well-ventilated warehouse; S12. Pretreatment of ammonia: Purification treatment: Use a scrubber or adsorption tower to remove dust, oil mist, and water vapor that may be contained in ammonia; Compression and cooling: compress and cool ammonia, and liquefy the compressed ammonia for long-term storage to meet the requirements of ammonia pressure and temperature in subsequent production processes; Stable supply system: Establish a stable ammonia supply system to ensure the continuous and stable supply of ammonia during the production process, including the configuration of ammonia storage tanks, pressure regulating devices, and flow control devices; S2. Reaction synthesis: The pretreated phosphate rock is reacted with sulfuric acid to generate phosphoric acid, which is then reacted with ammonia to generate monoammonium phosphate. The reaction temperature of the phosphate rock and sulfuric acid is 80-100 degrees Celsius, the reaction time is 2-6 hours, and the phosphoric acid concentration is 0.2 mol·L -1 -2mol·L -1 , reacting the generated phosphoric acid with ammonia at 20-80 degrees Celsius to generate monoammonium phosphate, and the reaction time is 2-6 hours; S3, crystallization: obtaining monoammonium phosphate crystals by cooling and crystallizing; S4, separation: separating monoammonium phosphate crystals from the mother liquor; S5, drying: drying the separated monoammonium phosphate crystals; S6. Packaging: Packaging the dried monoammonium phosphate to obtain a finished product.

[0005] Preferably, in step S1, the phosphate rock is first crushed to 150-200 mesh and then mixed with ammonia for pretreatment.

[0006] Preferably, in step S3, the crystallization temperature is 20-25 degrees Celsius and the crystallization time is 3-8 hours.

[0007] Preferably, in step S5, the drying temperature is 90-100 degrees Celsius and the drying time is 2-3 hours.

[0008] Compared with the prior art, the present invention has the following beneficial effects: The purpose of the present invention is to provide a novel production method of monoammonium phosphate, which greatly improves the purity and production efficiency of monoammonium phosphate and reduces energy consumption and environmental pollution by optimizing reaction conditions and process flow; at the same time, the monoammonium phosphate has better lamellar structure, chemical stability and flame retardant performance, and has broad agricultural and industrial application prospects, such as application in fertilizers and fire retardants, bread improvers, food additives, etc.; unnecessary steps, such as multiple crystallizations, filtration and washing, are reduced, thereby reducing energy consumption and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is the XRD pattern of monoammonium phosphate in the present invention; Figure 2 is the XRD pattern of existing monoammonium phosphate; Figure 3 This is a scanning electron microscope SEM image 1 of the existing monoammonium phosphate; Figure 4 This is the second scanning electron microscope SEM image of the existing monoammonium phosphate; Figure 5 Scanning electron microscope SEM image 1 of monoammonium phosphate in the present invention; Figure 6Scanning electron microscope SEM image 2 of monoammonium phosphate in the present invention; Figure 7 This is a 3D laser scanning microscope image of existing monoammonium phosphate; Figure 8 It is a 3D laser scanning microscope image of monoammonium phosphate in the present invention; Fig. 9 is a thermogravimetric analysis TGA graph of monoammonium phosphate in the present invention; DETAILED DESCRIPTION

[0010] The technical solution of the present invention is described in detail below in conjunction with embodiments, but the protection scope is not limited thereto. Example

[0011] A method for producing high-performance monoammonium phosphate comprises the following steps: S1. Raw material pretreatment: crush the phosphate rock to 200 mesh, mix it with ammonia for pretreatment, and remove organic impurities and heavy metals; S11. Pretreatment of phosphate rock: Crushing and screening: The phosphate ore is crushed coarsely and finely through a crusher to make its particle size reach the required range, and the ore is classified into different particle sizes using screening equipment; Washing and desludging: Removing dirt, sand and other impurities from the surface of phosphate rock by water washing or wet screening helps reduce the pollutant load in subsequent processing and improves the purity of the product; Magnetic separation and flotation: Magnetic separators are used to remove iron impurities from phosphate ore. At the same time, flotation technology is used to further separate phosphate minerals and other mineral impurities based on the differences in physical and chemical properties between ore and impurities, such as surface wettability and density. During the flotation process, it is often necessary to add an appropriate amount of flotation reagents to enhance the separation effect; Drying and storage: The treated phosphate rock is dried to remove excess moisture. The dried phosphate rock should be stored in a dry, well-ventilated warehouse to prevent moisture and contamination; S12. Pretreatment of ammonia: Purification treatment: Use a scrubber or adsorption tower to remove impurities such as dust, oil mist, and water vapor that may be contained in ammonia, which is beneficial to protecting subsequent process equipment and improving product quality; Compression and cooling: In order to facilitate storage and transportation, and to meet the pressure and temperature requirements of subsequent processes, ammonia usually needs to be compressed and cooled. The compressed ammonia may also need to be liquefied for long-term storage; Stable supply system: Establish a stable ammonia supply system to ensure the continuous and stable supply of ammonia during the production process, including the configuration and optimization of ammonia storage tanks, pressure regulating devices, flow control devices and other equipment; Through the above specific pretreatment steps, the purity of phosphate rock and ammonia can be significantly improved, providing high-quality raw materials for subsequent processing; S2. Reaction synthesis: In a reactor, the pretreated phosphate rock is reacted with 98% sulfuric acid to generate phosphoric acid. The reaction temperature is 90-100 degrees Celsius, the reaction time is 2 hours, and the phosphoric acid concentration is 0.2 mol·L -1 -2mol·L -1 ; The generated phosphoric acid is reacted with ammonia gas at 60-70 degrees Celsius to generate monoammonium phosphate for 3 hours; S3, crystallization: crystallization is performed by cooling to 25 degrees Celsius to obtain monoammonium phosphate crystals; S4, separation: separate the monoammonium phosphate crystals from the mother liquor by centrifuge, and the purity reaches more than 98%; S5, drying: drying the crystals at 100 degrees Celsius for 2 hours; S6. Packaging: Packaging the dried monoammonium phosphate to obtain a finished product. Example

[0012] A method for producing high-performance monoammonium phosphate comprises the following steps: S1. Raw material pretreatment: crush the phosphate rock to 150 mesh, mix it with ammonia for pretreatment, and remove organic impurities and heavy metals; S2. Reaction synthesis: In a reactor, the pretreated phosphate rock is reacted with 85% sulfuric acid to generate phosphoric acid. The reaction temperature is 80 degrees Celsius, the reaction time is 3 hours, and the phosphoric acid concentration is 0.2 mol·L -1 -2mol·L -1 ; The generated phosphoric acid is reacted with ammonia gas at 50 degrees Celsius to generate monoammonium phosphate for 2 hours; S3, crystallization: crystallization is performed by cooling to 20 degrees Celsius for 6 hours to obtain monoammonium phosphate crystals; S4, separation: separate the monoammonium phosphate crystals from the mother liquor by centrifuge, and the purity reaches more than 96%; S5, drying: drying the crystals at 90 degrees Celsius for 3 hours; S6. Packaging: Packaging the dried monoammonium phosphate to obtain a finished product.

[0013] The physicochemical properties and microstructure of the monoammonium phosphate product prepared in Example 1 of the present invention are described as follows: XRD characterization from Figure 1It can be seen that multiple significant diffraction peaks are mainly concentrated between 10° and 40° at 2θ. Identifying the positions of these peaks is the key to determining the crystal structure of the material. The intensity of the diffraction peak (peak height) indicates the crystallinity and relative content of the material. A peak with a higher intensity indicates that the crystal plane has a higher crystal plane density. According to the test results of X-ray diffraction, the product prepared in Example 1 of the present invention has a higher purity and fewer impurities than the monoammonium phosphate on the existing market, reduces the product purification process and production process, is more energy-saving and environmentally friendly, and has a clear crystal structure: multiple significant diffraction peaks in the XRD graph indicate that the monoammonium phosphate product has a good crystal structure. The positions of these peaks are mainly concentrated between 10° and 40° at 2θ, which is the key information for determining the crystal structure of the material. High crystallinity and purity: The higher the intensity of the diffraction peak, the higher the crystallinity and the higher the relative content of the product. The higher the intensity of the peak, the higher the crystal density of the crystal plane, which is usually proportional to the purity and order of the material. Figure 1 and Figure 2 By comparison, it can be inferred that the monoammonium phosphate product has a higher purity.

[0014] Low impurity content: Compared with the monoammonium phosphate currently on the market, the X-ray diffraction test results of the product of the present invention show that it has higher purity and fewer impurities; this means that during the preparation process, the product may have adopted a more effective technology or process for controlling impurities.

[0015] Simplified production process and purification process: Due to the high purity and low impurity content of the product, the subsequent purification process and production process can be reduced; this not only reduces production costs, but also helps to improve production efficiency; Energy saving and environmental protection: Reducing the purification process and production process not only reduces energy consumption, but also reduces the generation of waste, thus being more energy-saving and environmentally friendly. This is of great significance to the green production and sustainable development currently advocated.

[0016] In summary, this monoammonium phosphate product has significant advantages in the market due to its high purity, low impurity content and simplified production process, especially in terms of energy saving and environmental protection; 2. Scanning Electron Microscope Characterization The particle shapes are irregular, some are flake-shaped, some are block-shaped, some are granular, and there are even some spherical particles; the particle size range is large, ranging from a few microns to tens of microns, and some particles are even over 100 microns in size; the particle surface is rough, with a large number of small holes and cracks, indicating that there may be some voids or crystal structure defects inside the particles; the SEM image shows that the prepared monoammonium phosphate product has high purity and few impurities; Due to the small particle size and rough surface, the substance may have a larger specific surface area, which will be beneficial to its application in catalysis, adsorption, etc.; the voids and defects on the particle surface may increase its reaction activity and promote the occurrence of chemical reactions; the small particle size is conducive to its faster dissolution in the solution.

[0017] from Figure 3 , Figure 4 and Figure 5 , Figure 6 By comparison, it can be seen that the monoammonium phosphate produced by the present invention is relatively more uniform than the existing monoammonium phosphate particles, and the sizes range from 2 microns to 4 microns.

[0018] 3.3D laser scanning microscope (VK-X100K) characterization Figure 7 and Figure 8 The 3D laser scanning microscope image in the figure shows irregularly shaped powder agglomerates of monoammonium phosphate, with sizes ranging from tens of microns to hundreds of microns. The surface of the particles looks rough and has some small holes and cracks, which is caused by the incomplete crystal structure inside the particles or the gaps between the particles. In addition, the picture also shows some smaller particles, which are formed by the crushing or decomposition of larger particles. Figure 5 and Figure 6 The 3D laser scanning microscope image in the figure shows that the monoammonium phosphate powder agglomerates are flat, which is different from Figure 3 , Figure 4 , Figure 5 and Figure 6 The scanning microscope SEM images in the figure show that the monoammonium phosphate powder particles prepared by the present invention are mainly lamellar structures with basically uniform thickness. These characteristics affect and improve the properties of the substance, such as dissolution rate, reaction rate, adsorption performance, and flame retardancy; from Figure 7 and Figure 8 By comparison, it can be seen that the monoammonium phosphate of the present invention is more uniform in particles than the existing monoammonium phosphate, and it is easier to improve its adsorption and flame retardant properties; 4. Thermogravimetric Characterization Fig. 9 Thermogravimetric analysis (TGA) results obtained by two different treatment methods are shown; the black curve represents the curve of mass percentage directly measured versus temperature, while the red curve represents the derivative curve obtained after smoothing the mass percentage versus temperature curve; from Fig. 9It can be seen that the curve trends obtained by the two treatment methods are basically the same. At about 200°C, the mass percentage decreased significantly, which may be caused by the evaporation of volatile substances in the sample at high temperature; at about 500°C, the mass percentage decreased slowly, which may be caused by the decomposition of organic components in the sample at high temperature; The derivative curve can more clearly show the changes of the sample at different temperatures. From the red curve, we can see that there is an obvious negative peak at about 200°C, which corresponds to the starting point of the mass percentage decrease in the black curve. There is also a negative peak at about 500°C, but the amplitude is smaller, which corresponds to the trend of the slow decrease of the mass percentage in the black curve. Thermogravimetric analysis (TGA) of monoammonium phosphate provides information about the mass loss of the sample as it changes with temperature, which is very useful for understanding the thermal stability and composition of the sample. The following is a detailed interpretation of the TGA results described: Black curve (mass percentage versus temperature): The obvious drop at 200°C indicates that there are some substances in the sample that can volatilize at lower temperatures. These volatile substances may be water or other low-boiling point compounds in the sample. Slow decrease at 500°C: This indicates that the organic components or certain chemical bonds in the sample begin to decompose at high temperatures; this decomposition may be due to the pyrolysis of organic matter or the structural changes of inorganic matter; Red curve (derivative curve): Obvious negative peak at 200°C: This negative peak corresponds to the point in the black curve where the mass percentage begins to decrease significantly, which indicates that at this temperature, the mass loss rate of the sample reaches a local maximum; Smaller negative peak at 500°C: This negative peak corresponds to the slowly decreasing trend of the mass percentage in the black curve, which indicates that at this temperature, although the mass loss rate of the sample is small, it is still an important change point; In summary, the TGA graph of monoammonium phosphate shows the mass loss of the sample at different temperatures. By analyzing these curves, we can derive the thermal stability and composition changes of the sample at different temperatures. This is very helpful for understanding the thermal properties of monoammonium phosphate and its behavior at high temperatures; The combination of the thermogravimetric analysis TGA graph and the scanning electron microscope SEM graph shows that the monoammonium phosphate powder particles prepared by the present invention have chemical stability and flame retardant properties in a wider temperature range.

[0019] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for producing high-performance monoammonium phosphate, characterized in that: The following steps are involved: S1. Raw material pretreatment: pretreat phosphate rock and ammonia to remove impurities; S11. Pretreatment of phosphate rock: Crushing and screening: The phosphate ore is crushed coarsely and finely through a crusher to make its particle size reach the required range, and the ore is classified into different particle sizes using screening equipment; Washing and desludging: Remove dirt and sand from the surface of phosphate ore by water washing or wet screening; Magnetic separation and flotation: Use magnetic separators to remove iron impurities from phosphate ore; Drying and storage: The treated phosphate rock is dried to remove excess moisture and should be stored in a dry, well-ventilated warehouse; S12. Pretreatment of ammonia: Purification treatment: Use a scrubber or adsorption tower to remove dust, oil mist, and water vapor that may be contained in ammonia; Compression and cooling: compress and cool ammonia, and liquefy the compressed ammonia for long-term storage to meet the requirements of ammonia pressure and temperature in subsequent production processes; Stable supply system: Establish a stable ammonia supply system to ensure the continuous and stable supply of ammonia during the production process, including the configuration of ammonia storage tanks, pressure regulating devices, and flow control devices; S2. Reaction synthesis: The pretreated phosphate rock is reacted with sulfuric acid to generate phosphoric acid, which is then reacted with ammonia to generate monoammonium phosphate. The reaction temperature of the phosphate rock and sulfuric acid is 80-100 degrees Celsius, the reaction time is 2-6 hours, and the phosphoric acid concentration is 0.2 mol·L -1 -2mol·L -1 , reacting the generated phosphoric acid with ammonia at 20-80 degrees Celsius to generate monoammonium phosphate, and the reaction time is 2-6 hours; S3, crystallization: obtaining monoammonium phosphate crystals by cooling and crystallizing; S4, separation: separate the monoammonium phosphate crystals from the mother liquor by centrifuge, and the purity reaches more than 98%; S5, drying: drying the separated monoammonium phosphate crystals; S6. Packaging: Packaging the dried monoammonium phosphate to obtain a finished product.

2. The method for producing high-performance monoammonium phosphate according to claim 1, characterized in that: In step S1, the phosphate rock is first crushed to 150-200 meshes and then mixed with ammonia for pretreatment.

3. The method for producing high-performance monoammonium phosphate according to claim 1, characterized in that: In step S3, the crystallization temperature is 20-25 degrees Celsius, and the crystallization time is 3-8 hours.

4. The method for producing high-performance monoammonium phosphate according to claim 1, characterized in that: In step S5, the drying temperature is 90-100 degrees Celsius and the drying time is 2-3 hours.

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