A method for preparing high purity solid amps sodium salt particles

Abstract

The application discloses a preparation method of high-purity solid AMPS sodium salt particles and belongs to the technical field of AMPS sodium salt particle preparation, and comprises the following steps: low-temperature controllable neutralization: crude AMPS raw material without recrystallization purification is prepared into an AMPS aqueous solution with a mass concentration of 35%-45% by being mixed with deionized water, sodium hydroxide solution is continuously added dropwise for neutralization under continuous stirring, the temperature of the material liquid is controlled to be 10-25 DEG C, and the pH at the neutralization end point is controlled to be 8.2-9.0. In the application, the crude AMPS raw material without recrystallization purification is directly used as a production raw material, so that the raw material pre-purification process necessary in the traditional process is omitted, the production process flow is greatly simplified, material loss and equipment investment are reduced, the overall production cost and production energy consumption are effectively reduced, the production cycle is shortened, and the defects of the traditional process, such as complicated process, high cost and long cycle, are solved.

Description

Technical Field

[0001] This invention relates to the field of AMPS sodium salt particle preparation technology, and more specifically, to a method for preparing high-purity solid AMPS sodium salt particles. Background Technology

[0002] Sodium 2-acrylamido-2-methylpropanesulfonic acid (AMPS) is an important anionic functional monomer with excellent water solubility, temperature resistance, and salt resistance. It is widely used in water treatment flocculants, oilfield flooding polymers, papermaking additives, and paint thickeners. Currently, the industrial production of AMPS sodium salt generally uses refined AMPS monomers as raw materials, which are dissolved in water, neutralized, and then crystallized by conventional cooling or evaporation to obtain solid sodium salt products. To ensure the purity of the final product, the industry typically requires pre-recrystallization purification of the crude AMPS raw material to remove impurities such as acrylonitrile, inorganic sulfates, and oligomers before neutralization and crystallization. This is currently the mainstream industrial production method.

[0003] However, existing traditional preparation methods have significant technical defects and production shortcomings: First, to ensure product purity, traditional processes require pre-recrystallization and purification of crude AMPS raw materials, resulting in cumbersome production procedures, long production cycles, and high material losses, significantly increasing energy consumption and preparation costs. Second, traditional crystallization processes often employ a one-time addition of organic solvents and rapid cooling crystallization, which can cause instantaneous supersaturation of the liquid, easily trapping impurities such as acrylonitrile, inorganic sulfates, and AMPS oligomers inside the crystals, leading to incomplete impurity removal and low product purity. Third, traditional crystallization processes lack gradient temperature control, resulting in uncontrollable crystal growth rates, easily generating large amounts of fine powder and broken crystals, poor particle regularity and uniformity, poor material flowability, and poor product appearance and quality stability. Fourth, conventional neutralization crystallization systems have wide temperature control, making monomers prone to slight polymerization and unable to effectively remove colored and insoluble impurities from the system, resulting in inconsistent product quality that fails to meet the standards for high-end fine chemical products.

[0004] Based on this, the present invention designs a method for preparing high-purity solid AMPS sodium salt particles to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing high-purity solid AMPS sodium salt particles to solve the problems mentioned in the background art.

[0006] A method for preparing high-purity solid AMPS sodium salt particles includes the following steps: S1. Low-temperature controllable neutralization: Prepare an AMPS aqueous solution with a mass concentration of 35% to 45% by mixing crude AMPS raw material that has not been recrystallized and purified with deionized water. Stir continuously and add sodium hydroxide solution dropwise for neutralization. Control the temperature of the solution at 10 to 25°C. Control the pH at the neutralization endpoint at 8.2 to 9.0. After neutralization, add a polymerization inhibitor to obtain a neutralized solution. The purity of the crude AMPS raw material is 92-96 wt%, and the raw material contains acrylonitrile, inorganic sulfate and AMPS oligomer impurities. S2. Pretreatment, decolorization and filtration: Add activated carbon to the neutralized liquid obtained in step S1, keep warm and stir for decolorization, and remove activated carbon and insoluble impurities by precision filtration to obtain crude mother liquor of AMPS sodium salt. S3. Selective dissolution crystallization granulation: Place the crude mother liquor of AMPS sodium salt in a crystallization kettle, and continuously and uniformly add an organic solvent with dissolution effect under stirring conditions. During the entire process of adding organic solvent, a three-stage program temperature control is executed simultaneously to regulate the supersaturation of the liquid in stages. S4. Solid-liquid separation and solvent rinsing: The crystallized suspension is centrifuged to obtain a filter cake, which is then rinsed multiple times with the organic solvent. S5. Low-temperature vacuum drying: The filter cake after rinsing is vacuum dried to obtain high-purity solid AMPS sodium salt particles.

[0007] Preferably, in step S1, the polymerization inhibitor is p-hydroxyanisole, the amount of polymerization inhibitor added is 30-60 ppm of the total mass of the neutralized solution obtained after neutralization, the mass concentration of the sodium hydroxide solution used for neutralization is 20%-32%, and the dripping time is 1.5-3h.

[0008] Preferably, in step S2, the amount of activated carbon added is 0.3% to 1.0% of the mass of the neutralized liquid, the decolorization temperature is 15 to 25°C, the stirring and decolorization time is 30 to 90 min, and the filtration accuracy is 0.45 μm.

[0009] Preferably, in step S3, the organic solvent is selected from any one or more mixtures of methanol, ethanol, and isopropanol, and the volume ratio of the organic solvent to the crude mother liquor of AMPS sodium salt is 0.7:1 to 1.6:1.

[0010] Preferably, in step S3, the three-stage programmed temperature control process is as follows: initial temperature of 22-25℃ is maintained for 0.5h; the temperature is reduced to 10-12℃ at a rate of 0.3-0.6℃ / h and maintained for 1h; the temperature is further reduced to 0-5℃ at a rate of 0.5-1.0℃ / h and maintained for 2-4h for ripening.

[0011] Preferably, in step S3, the stirring rate is 180-350 r / min, and in step S4, the centrifugal speed is controlled at 2500-4000 r / min, and the filter cake is washed 2-3 times.

[0012] Preferably, in step S5, the drying temperature of vacuum drying is not higher than 45°C, the vacuum degree is controlled between -0.07 and -0.095 MPa, and the product moisture content is dried to ≤0.3 wt%.

[0013] Preferably, the crude AMPS raw material contains 200-800 ppm acrylonitrile and 0.3-1.0 wt% inorganic sulfate.

[0014] Compared with the prior art, the advantages of this invention are: 1. This invention uses crude AMPS raw material that has not been recrystallized and purified directly as the production raw material, which eliminates the raw material pre-purification process required by traditional processes, greatly simplifies the production process, reduces material loss and equipment investment, effectively reduces the overall production cost and energy consumption, shortens the production cycle, and solves the defects of traditional processes that are cumbersome, costly and time-consuming.

[0015] 2. This invention replaces the traditional method of adding solvent all at once by uniformly adding an organic solvent with a dissolving effect during the crystallization process. This achieves stable and controllable supersaturation of the system, avoids the explosive nucleation and impurity encapsulation caused by instantaneous high supersaturation, significantly improves the impurity separation effect and the purity of the finished product, and effectively reduces the residual amount of acrylonitrile, inorganic sulfate and AMPS oligomers in the finished product. It solves the defects of incomplete impurity removal and low purity of the finished product in the traditional process.

[0016] 3. This invention provides a suitable environment for the orderly and stable growth of crystals by matching a three-stage gradient temperature control process throughout the entire process of solvent addition and adjusting the supersaturation of the solution in stages. This effectively avoids the problems of fine and broken crystals caused by rapid cooling, improves the regularity and uniformity of product particles, and improves the product's flowability and appearance. It solves the defects of poor crystal morphology, uneven particle size, and insufficient product stability in traditional processes.

[0017] 4. This invention utilizes a pretreatment system combining low-temperature neutralization with activated carbon decolorization and filtration to effectively remove colored and insoluble impurities from the system while preventing the polymerization and deterioration of AMPS monomers. This system steadily improves the light transmittance and overall quality of the product, solving the problem of inconsistent product quality and difficulty in meeting the needs of high-end applications caused by traditional processes. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of a method for preparing high-purity solid AMPS sodium salt particles proposed in this invention. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The following examples and comparative examples all use industrial crude AMPS raw materials, all of which are industrial crude products that have not been recrystallized and purified.

[0021] Standardized testing indicators: purity of AMPS sodium salt in finished product, residual acrylonitrile, inorganic sulfate content, AMPS oligomer content, and product appearance.

[0022] Example 1: The crude AMPS raw material used has a purity of 94.0 wt%, an acrylonitrile content of 420 ppm, an inorganic sulfate content of 0.65 wt%, and an AMPS oligomer content of 2.2 wt%.

[0023] S1. Low-temperature controllable neutralization: Unrecrystallized crude AMPS raw material is mixed with deionized water to prepare an AMPS aqueous solution with a mass concentration of 40%. The solution is continuously stirred and sodium hydroxide solution is added dropwise for neutralization. The temperature of the solution is controlled at 18°C, and the pH at the neutralization endpoint is controlled at 8.6. After neutralization, p-hydroxyanisole is added to obtain a neutralized solution. The amount of p-hydroxyanisole added is 45 ppm of the total mass of the neutralized solution obtained after neutralization. The mass concentration of the sodium hydroxide solution used is 26 wt%, and the dropwise addition time is 2 h.

[0024] S2. Pretreatment, decolorization and filtration: Add activated carbon to the neutralized solution obtained in step S1. The amount of activated carbon added is 0.6% of the mass of the neutralized solution. The decolorization temperature is 20℃. Keep warm and stir for 60 min to decolorize. Remove activated carbon and insoluble impurities through 0.45μm precision filtration to obtain crude mother liquor of AMPS sodium salt.

[0025] S3. Selective dissolution crystallization granulation: The crude mother liquor of AMPS sodium salt is placed in a crystallization vessel, and ethanol with dissolution effect is continuously and uniformly added dropwise under stirring conditions; a three-stage temperature program is implemented simultaneously throughout the ethanol dropwise process to control the supersaturation of the liquid in stages; the stirring rate is 260 r / min; the volume ratio of ethanol to crude mother liquor of AMPS sodium salt is 1.1:1; the three-stage temperature program is as follows: the initial temperature is 24℃ and held for 0.5 h; the temperature is reduced to 11℃ at a rate of 0.45℃ / h and held for 1 h; the temperature is further reduced to 3℃ at a rate of 0.7℃ / h and held for 3 h for maturation.

[0026] S4. Solid-liquid separation and solvent rinsing: The crystallized suspension is centrifuged to obtain a filter cake, which is then rinsed twice with the ethanol; the centrifugation speed is 3200 r / min.

[0027] S5. Low-temperature vacuum drying: The washed filter cake is vacuum dried at a temperature not exceeding 42℃ and a vacuum degree of -0.08MPa until the product moisture content is ≤0.3wt%, thus obtaining high-purity solid AMPS sodium salt particles.

[0028] Test results: AMPS sodium salt purity 99.42wt%; acrylonitrile residue <15ppm; inorganic sulfate 0.04wt%; AMPS oligomer 0.18wt%; appearance is uniform and regular granules.

[0029] Example 2: The crude AMPS raw material used is exactly the same as that in Example 1.

[0030] S1. Low-temperature controllable neutralization: Unrecrystallized crude AMPS raw material is mixed with deionized water to prepare an AMPS aqueous solution with a mass concentration of 35%. The solution is continuously stirred and sodium hydroxide solution is added dropwise for neutralization. The temperature of the solution is controlled at 10°C, and the pH at the neutralization endpoint is controlled at 8.6. After neutralization, p-hydroxyanisole is added to obtain a neutralized solution. The amount of p-hydroxyanisole added is 30 ppm of the total mass of the neutralized solution obtained after neutralization. The mass concentration of the sodium hydroxide solution used is 20 wt%, and the dropwise addition time is 1.5 h.

[0031] S2. Pretreatment, decolorization and filtration: Add activated carbon to the neutralized solution obtained in step S1. The amount of activated carbon added is 0.3% of the mass of the neutralized solution. The decolorization temperature is 15℃. Keep warm and stir for 30 min to decolorize. Remove activated carbon and insoluble impurities through 0.45μm precision filtration to obtain crude mother liquor of AMPS sodium salt.

[0032] S3. Selective dissolution crystallization granulation: The crude mother liquor of AMPS sodium salt is placed in a crystallization vessel, and ethanol with dissolution effect is continuously and uniformly added dropwise under stirring conditions; a three-stage temperature program is implemented simultaneously throughout the ethanol dropwise process to control the supersaturation of the liquid in stages; the stirring rate is 180 r / min; the volume ratio of ethanol to crude mother liquor of AMPS sodium salt is 0.7:1; the three-stage temperature program is as follows: the initial temperature is 22℃ and held for 0.5 h; the temperature is reduced to 10℃ at a rate of 0.3℃ / h and held for 1 h; the temperature is further reduced to 0℃ at a rate of 0.5℃ / h and held for 3 h for maturation.

[0033] S4. Solid-liquid separation and solvent rinsing: The crystallized suspension is centrifuged to obtain a filter cake, which is then rinsed twice with the ethanol; the centrifugation speed is 2500 r / min.

[0034] S5. Low-temperature vacuum drying: The washed filter cake is vacuum dried at a temperature not exceeding 40°C and a vacuum degree of -0.08MPa until the product moisture content is ≤0.3wt%, thus obtaining high-purity solid AMPS sodium salt particles.

[0035] Test results: AMPS sodium salt purity 99.25wt%; acrylonitrile residue <18ppm; inorganic sulfate 0.05wt%; AMPS oligomer 0.22wt%; appearance is intact granular crystals.

[0036] Example 3: The crude AMPS raw material used is exactly the same as that in Example 1.

[0037] S1. Low-temperature controllable neutralization: Unrecrystallized crude AMPS raw material is mixed with deionized water to prepare an AMPS aqueous solution with a mass concentration of 45%. The solution is continuously stirred and sodium hydroxide solution is added dropwise for neutralization. The temperature of the solution is controlled at 25°C, and the pH at the neutralization endpoint is controlled at 8.6. After neutralization, p-hydroxyanisole is added to obtain a neutralized solution. The amount of p-hydroxyanisole added is 60 ppm of the total mass of the neutralized solution obtained after neutralization. The mass concentration of the sodium hydroxide solution used is 32 wt%, and the dropwise addition time is 3 h.

[0038] S2. Pretreatment, decolorization and filtration: Add activated carbon to the neutralized solution obtained in step S1. The amount of activated carbon added is 1.0% of the mass of the neutralized solution. The decolorization temperature is 25℃. Keep warm and stir for 90 min to decolorize. Remove activated carbon and insoluble impurities through 0.45μm precision filtration to obtain crude mother liquor of AMPS sodium salt.

[0039] S3. Selective dissolution crystallization granulation: The crude mother liquor of AMPS sodium salt is placed in a crystallization vessel, and ethanol with dissolution effect is continuously and uniformly added dropwise under stirring conditions; a three-stage temperature program is implemented simultaneously throughout the ethanol dropwise process to control the supersaturation of the liquid in stages; the stirring rate is 350 r / min; the volume ratio of ethanol to crude mother liquor of AMPS sodium salt is 1.6:1; the three-stage temperature program is as follows: the initial temperature is 25℃ and held for 0.5 h; the temperature is reduced to 12℃ at a rate of 0.6℃ / h and held for 1 h; the temperature is further reduced to 5℃ at a rate of 1.0℃ / h and held for 3 h for maturation.

[0040] S4. Solid-liquid separation and solvent rinsing: The crystallized suspension is centrifuged to obtain a filter cake, which is then rinsed three times with the ethanol; the centrifugation speed is 4000 r / min.

[0041] S5. Low-temperature vacuum drying: The washed filter cake is vacuum dried at a temperature not exceeding 45°C and a vacuum degree of -0.08MPa until the product moisture content is ≤0.3wt%, thus obtaining high-purity solid AMPS sodium salt particles.

[0042] Test results: AMPS sodium salt purity 99.31wt%; acrylonitrile residue <16ppm; inorganic sulfate 0.04wt%; AMPS oligomer 0.20wt%; appearance is intact granular crystals.

[0043] Example 4: The crude AMPS raw material used was another batch of industrial crude AMPS that had not been recrystallized and purified, with a purity of 92.5 wt%, an acrylonitrile content of 720 ppm, an inorganic sulfate content of 0.85 wt%, and an AMPS oligomer content of 3.1 wt%. The impurity content of the raw material was higher than that of the raw materials in Examples 1-3.

[0044] All preparation process steps and process parameters in this embodiment are exactly the same as in Example 1, except that the crude AMPS raw material is replaced.

[0045] Test results: AMPS sodium salt purity 99.18wt%; acrylonitrile residue <20ppm; inorganic sulfate 0.06wt%; AMPS oligomer 0.24wt%; appearance is uniform and intact granular crystals.

[0046] Comparative Example 1: Steps S1 and S2, and the parameters, are exactly the same as in Example 1.

[0047] S3. Selective dissolution crystallization granulation: Place the crude mother liquor of AMPS sodium salt in a crystallization kettle, and add all the ethanol at once under stirring conditions; after the addition is completed, implement a three-stage temperature program to control the supersaturation of the liquid in stages; the stirring rate is 260 r / min; the volume ratio of ethanol to crude mother liquor of AMPS sodium salt is 1.1:1; the three-stage temperature program is as follows: the initial temperature is 24℃ and held for 0.5 h; the temperature is reduced to 11℃ at a rate of 0.45℃ / h and held for 1 h; the temperature is further reduced to 3℃ at a rate of 0.7℃ / h and held for 3 h for maturation.

[0048] Steps and parameters S4 and S5 are completely consistent with those in Example 1.

[0049] Test results: AMPS sodium salt purity 97.16wt%; acrylonitrile residue 112ppm; inorganic sulfate 0.27wt%; AMPS oligomer 0.86wt%; the product is mainly composed of a large amount of fine powder, with no regular particles.

[0050] Comparative Example 2: Steps S1 and S2, and the parameters, are exactly the same as in Example 1.

[0051] S3. Selective dissolution crystallization granulation: Place the crude mother liquor of AMPS sodium salt in a crystallization vessel, and continuously and uniformly add ethanol with dissolution effect under stirring conditions; the stirring rate is 260 r / min; the volume ratio of ethanol to crude mother liquor of AMPS sodium salt is 1.1:1; after the ethanol is added, directly and rapidly cool down to 3℃ and keep warm for 3h.

[0052] Steps and parameters S4 and S5 are completely consistent with those in Example 1.

[0053] Test results: AMPS sodium salt purity 97.83wt%; acrylonitrile residue 78ppm; inorganic sulfate 0.19wt%; AMPS oligomer 0.64wt%; fine crystals with uneven morphology.

[0054] Comparative Example 3: The same batch of crude AMPS raw material as in Example 1 was used. Pre-recrystallization purification was performed using a water-ethanol system to remove acrylonitrile, inorganic sulfates, and AMPS oligomer impurities. The purified AMPS was then mixed with deionized water to prepare a 40% aqueous solution. The solution was continuously stirred and sodium hydroxide solution was added dropwise for neutralization. The temperature of the solution was controlled at 18°C, and the pH at the neutralization endpoint was controlled at 8.6. After neutralization, p-hydroxyanisole (45 ppm) was added to obtain a neutralized solution. Subsequent activated carbon decolorization and filtration were performed as in Example 1. The resulting mother liquor was crystallized directly using a gradient cooling process without adding any solvent. Subsequent centrifugation, rinsing, and drying conditions were consistent with those in Example 1.

[0055] Test results: AMPS sodium salt purity 98.45wt%; acrylonitrile residue 48ppm; inorganic sulfate 0.13wt%; AMPS oligomer 0.5wt%; appearance: granules.

[0056] Summary of Experimental Results ; Experimental conclusions By comparing the various embodiments of the present invention with Comparative Examples 1, 2, and 3, it can be seen that the method of the present invention has the following advantages: Compared to Comparative Example 1, this invention employs a uniformly dripping organic solvent with a dissolving effect, combined with a three-stage gradient temperature-controlled crystallization process. This allows for precise control of the supersaturation of the liquid, avoiding impurity encapsulation and crystal fragmentation caused by instantaneous supersaturation. The purity of the finished products in each embodiment is significantly higher than that in Comparative Example 1. The removal of impurities such as acrylonitrile, inorganic sulfates, and AMPS oligomers is greatly improved, resulting in the stable formation of regular granular products. This completely solves the defects of low purity and excessive fine powder in traditional rapid cooling crystallization products.

[0057] Compared to Comparative Example 2, this invention provides a stable environment for orderly crystal growth through the coupling effect of segmented heating and cooling curing, effectively suppressing the co-precipitation of impurities and the formation of crystal defects. The products of each embodiment have higher purity and lower impurity residue, while the crystal morphology is uniform and regular, and the quality is far superior to the fine and uneven crystal products of Comparative Example 2, demonstrating outstanding advantages in crystallization purification and granulation effects.

[0058] Compared to Comparative Example 3, this invention eliminates the need for a cumbersome pre-recrystallization purification process for crude AMPS raw materials, significantly simplifying the production process, reducing energy consumption and labor costs, and shortening the production cycle. Even when using high-impurity crude raw materials directly, the purity, impurity removal effect, and crystal regularity of the resulting product are all superior to the traditional process product of Comparative Example 3. This overcomes the technical bias of prior purification of raw materials required by existing technologies, achieving the technical effect of low-cost, high-efficiency, and high-quality preparation of high-purity AMPS sodium salt particles.

[0059] Meanwhile, Examples 1-4 cover the entire process parameter range of the present invention and crude raw material systems with different impurity contents, and all of them can obtain high-purity and well-formed products with a purity of over 99%, proving that the process parameters of the present invention have wide adaptability and strong production stability, and have excellent industrial application value.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-purity solid AMPS sodium salt particles, characterized in that, Includes the following steps: S1. Low-temperature controllable neutralization: Prepare an AMPS aqueous solution with a mass concentration of 35% to 45% by mixing crude AMPS raw material that has not been recrystallized and purified with deionized water. Stir continuously and add sodium hydroxide solution dropwise for neutralization. Control the temperature of the solution at 10 to 25°C. Control the pH at the neutralization endpoint at 8.2 to 9.

0. After neutralization, add a polymerization inhibitor to obtain a neutralized solution. The purity of the crude AMPS raw material is 92-96 wt%, and the raw material contains acrylonitrile, inorganic sulfate and AMPS oligomer impurities. S2. Pretreatment, decolorization and filtration: Add activated carbon to the neutralized liquid obtained in step S1, keep warm and stir for decolorization, and remove activated carbon and insoluble impurities by precision filtration to obtain crude mother liquor of AMPS sodium salt. S3. Selective dissolution crystallization granulation: Place the crude mother liquor of AMPS sodium salt in a crystallization kettle, and continuously and uniformly add an organic solvent with dissolution effect under stirring conditions. During the entire process of adding organic solvent, a three-stage program temperature control is executed simultaneously to regulate the supersaturation of the liquid in stages. S4. Solid-liquid separation and solvent rinsing: The crystallized suspension is centrifuged to obtain a filter cake, which is then rinsed multiple times with the organic solvent. S5. Low-temperature vacuum drying: The filtered cake after rinsing is vacuum dried to obtain high-purity solid AMPS sodium salt particles.

2. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, In step S1, the polymerization inhibitor is p-hydroxyanisole, and the amount of polymerization inhibitor added is 30-60 ppm of the total mass of the neutralized solution obtained after neutralization. The mass concentration of the sodium hydroxide solution used for neutralization is 20%-32%, and the dripping time is 1.5-3 hours.

3. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, In step S2, the amount of activated carbon added is 0.3% to 1.0% of the mass of the neutralized liquid, the decolorization temperature is 15 to 25°C, the stirring and decolorization time is 30 to 90 min, and the filtration accuracy is 0.45 μm.

4. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, In step S3, the organic solvent is selected from any one or more mixtures of methanol, ethanol, and isopropanol, and the volume ratio of the organic solvent to the crude mother liquor of AMPS sodium salt is 0.7:1 to 1.6:

1.

5. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, In step S3, the three-stage programmed temperature control process is as follows: the initial temperature is 22-25℃ and held for 0.5h; the temperature is then reduced to 10-12℃ at a rate of 0.3-0.6℃ / h and held for 1h; the temperature is then further reduced to 0-5℃ at a rate of 0.5-1.0℃ / h and held for 2-4h for curing.

6. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, In step S3, the stirring rate is 180-350 r / min. In step S4, the centrifugal speed is controlled at 2500-4000 r / min, and the filter cake is washed 2-3 times.

7. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, In step S5, the drying temperature of vacuum drying is not higher than 45℃, the vacuum degree is controlled between -0.07 and -0.095 MPa, and the product moisture content is dried to ≤0.3wt%.

8. The method for preparing high-purity solid AMPS sodium salt particles according to claim 1, characterized in that, The crude AMPS raw material contains 200–800 ppm acrylonitrile and 0.3–1.0 wt% inorganic sulfate.

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