A sodium carbonate raw material particle size detection method for a sodium ion positive electrode material

Abstract

This invention relates to a method for particle size determination of sodium carbonate raw materials used in sodium-ion cathode materials, belonging to the field of analytical testing technology. The method first prepares a saturated alcohol-based solution of sodium carbonate using alcohol-based chemical reagents, then prepares a dispersant solution using sodium oleate as a dispersant. The battery-grade sodium carbonate sample to be tested is added to the dispersant solution, and after ultrasonic dispersion, the particle size distribution is detected using a laser particle size analyzer. This invention employs a wet dispersion detection method, combining sodium oleate dispersant and alcohol-based reagents, effectively solving the problems of inaccurate detection data and poor repeatability caused by the small particle size and easy agglomeration of battery-grade sodium carbonate.

Description

Technical Field

[0001] This invention relates to the field of analytical testing technology, and in particular to a method for detecting the particle size of sodium carbonate raw materials used in sodium ion cathode materials. Background Technology

[0002] As a key raw material in the field of new energy batteries such as sodium batteries, the particle size and distribution of battery-grade sodium carbonate directly affect the electrochemical performance, cycle stability and safety of the battery. Therefore, accurate detection of its particle size is the core link in the quality control and product acceptance of battery-grade sodium carbonate production.

[0003] Currently, particle size detection is mainly divided into two methods: dry and wet. Among them, dry detection is widely used for particle size detection of conventional powder materials due to its advantages of simple operation and no need for dispersion medium. However, it has significant limitations for battery-grade sodium carbonate: battery-grade sodium carbonate has extremely small particle size (typically D50 of 2–5 μm), high surface energy, and is prone to electrostatic adsorption and agglomeration. When using dry airflow dispersion, fine particles are prone to sticking to the wall and insufficient dispersion, resulting in unstable light-blocking during the detection process. The final measured particle size data is seriously overestimated and has poor repeatability, failing to reflect the original true particle size and making it difficult to meet the stringent quality control requirements of battery-grade products.

[0004] Wet dispersion assays are the preferred method for particle size analysis of fine-grained materials due to their good dispersion effect and high detection accuracy. However, existing wet dispersion assays face two major challenges when applied to battery-grade sodium carbonate: First, the choice of dispersion medium is difficult. Battery-grade sodium carbonate is slightly soluble in water. If water is used as the dispersion medium, some particles will dissolve, resulting in undersized particles and distorted distribution. If conventional organic solvents (such as alcohol solvents) are used as the dispersion medium, although the solubility can be reduced, their slight solubility cannot be completely eliminated, and detection errors caused by particle dissolution will still occur in long-term testing. Second, there is the problem of agglomeration. Battery-grade sodium carbonate particles are highly agglomerated, and conventional dispersants are difficult to effectively break up their soft agglomerates. Even with ultrasonic dispersion, agglomerates are prone to re-agglomeration, further affecting the detection accuracy.

[0005] Therefore, given the characteristics of battery-grade sodium carbonate—small particle size, easy agglomeration, and slight solubility in organic solvents—developing a particle size detection method that can completely solve the problems of inaccurate dry methods, easy dissolution by conventional wet methods, and difficulty in breaking agglomerates, and achieving accurate detection of its true particle size, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a method for detecting the particle size of sodium carbonate raw materials for sodium ion cathode materials, in order to solve at least one of the technical problems existing in the current battery-grade sodium carbonate particle size detection, such as inaccurate dry method, easy dissolution by wet method, and difficulty in breaking up agglomerates.

[0007] This invention provides a method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials, comprising the following steps: S1. Add an excess of the battery-grade sodium carbonate sample to be tested to the alcohol-based chemical reagent, stir thoroughly, let stand for separation, and take the supernatant to obtain a saturated sodium carbonate alcohol solution. S2. Add sodium oleate to the saturated sodium carbonate alcohol solution obtained in step S1, and stir until the sodium oleate is completely dissolved to prepare a dispersant solution; S3. Weigh the battery-grade sodium carbonate sample to be tested, add it to the dispersant solution obtained in step S2, stir evenly, and obtain a sample suspension. S4. Place the sample suspension from step S3 in an ultrasonic disperser and perform ultrasonic dispersion. S5. The sample suspension processed in step S4 is injected into the sample cell of the laser particle size analyzer for particle size detection to obtain the particle size data of the battery-grade sodium carbonate sample to be tested.

[0008] Further, in step S1, the alcohol-based chemical reagent includes one or more of anhydrous ethanol, anhydrous isopropanol, and anhydrous n-butanol.

[0009] Furthermore, in step S1, the stirring time is 30~60 min and the stirring speed is 50~200 r / min.

[0010] Further, in step S2, the mass fraction of sodium oleate in the dispersant solution is 0.05~0.75%.

[0011] Further, in step S2, the mass fraction of sodium oleate in the dispersant solution is 0.1~0.5%.

[0012] Furthermore, in step S2, the mass fraction of sodium oleate in the dispersant solution is 0.25~0.5%.

[0013] Furthermore, in step S3, the amount of the battery-grade sodium carbonate sample to be tested added is 0.1~0.4 g.

[0014] Further, in step S3, the amount of the dispersant solution used is 10~60 mL.

[0015] Furthermore, in step S4, the ultrasound time is 0.5~6 min and the ultrasound power is 50~300 W.

[0016] Furthermore, in step S4, the ultrasound time is 1-5 minutes and the ultrasound power is 50-300 W.

[0017] Furthermore, in step S5, the operating parameters of the laser particle size analyzer are as follows: the stirring speed of the instrument is adjusted to 100~500 r / min, and the sample occlusion is controlled to be 6~12%.

[0018] Furthermore, in step S5, a laser particle size analyzer is used to continuously detect the particle size 2 to 4 times, and the average value of the multiple detection results is taken as the final particle size data.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. More accurate than dry detection: This invention uses wet dispersion detection, combined with sodium oleate dispersant and alcohol-based reagents, to effectively solve the problem of inaccurate detection data and poor repeatability caused by the small particle size and easy agglomeration of battery-grade sodium carbonate. It avoids fine particles sticking to the wall, ensures that the particles are fully dispersed, and the detection data can truly reflect the true particle size, with good repeatability and small error. 2. Effectively solves the problem of detection distortion caused by slight solubility: This invention forms a solid-liquid dissolution balance by pre-preparing a saturated sodium carbonate anhydrous ethanol solution, completely eliminating the problems of particle erosion and small particle size caused by slight solubility of sodium carbonate, and ensuring the accuracy of detection results; 3. Strong adaptability of dispersion system: The present invention uses sodium oleate as a dispersant. As an anionic surfactant, it can be quickly adsorbed on the surface of sodium carbonate particles, improving the wettability of particles in anhydrous ethanol medium. At the same time, it generates a steric hindrance effect, effectively preventing the re-formation of agglomerates. It does not react with sodium carbonate and does not damage the particle structure, thus adapting to the characteristics of battery-grade sodium carbonate. 4. Saves on equipment procurement and usage costs, and is more practical: This invention adopts wet detection, eliminating the need to purchase additional dry dispersion equipment. It can directly use existing conventional wet laser particle size analyzers in laboratories to complete the detection without the need to modify the equipment, which greatly reduces the cost of equipment procurement, maintenance and usage. It is more suitable for low-cost and efficient detection of batch samples in industrial production and is easy to promote and apply on a large scale.

[0020] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0021] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0022] Figure 1 Particle size distribution diagram of Example 1 Figure 2 Particle size distribution diagram of Example 2 Figure 3 Particle size distribution diagram of Comparative Example 1 Figure 4 Particle size distribution diagram for Comparative Example 2 Detailed Implementation The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] Battery-grade sodium carbonate is a key raw material for sodium-ion batteries, and its particle size directly affects battery performance, making accurate testing crucial.

[0024] Existing methods for detecting the particle size of sodium carbonate raw materials in sodium-ion battery cathode materials are generally divided into dry detection and wet detection, but both have the following problems: 1. In dry testing, due to the fine particle size of the material (D50 is 2~5μm), it is easy to agglomerate and stick to the wall, resulting in the measured particle size being too large and having poor repeatability, which cannot reflect the true situation.

[0025] 2. Wet testing faces two major challenges: first, the material is slightly soluble in water and organic solvents, which leads to particle erosion and results that are too small; second, conventional methods are insufficient to break up its strong agglomeration, affecting the accuracy of the test.

[0026] Therefore, in response to the above-mentioned technical problems, the researchers of this invention propose a novel particle size detection method. By optimizing the dispersion system and improving the detection process, the method achieves accurate and stable detection of the true particle size of battery-grade sodium carbonate, thus meeting the quality control requirements of battery-grade products.

[0027] This invention provides a method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials, comprising the following steps: S1. Add an excess of the battery-grade sodium carbonate sample to be tested to the alcohol-based chemical reagent, stir thoroughly, let stand for separation, and take the supernatant to obtain a saturated sodium carbonate alcohol solution. S2. Add sodium oleate to the saturated sodium carbonate alcohol solution obtained in step S1, and stir until the sodium oleate is completely dissolved to prepare a dispersant solution; S3. Weigh the battery-grade sodium carbonate sample to be tested, add it to the dispersant solution obtained in step S2, stir evenly, and obtain a sample suspension. S4. Place the sample suspension from step S3 in an ultrasonic disperser and perform ultrasonic dispersion. S5. The sample suspension processed in step S4 is injected into the sample cell of the laser particle size analyzer for particle size detection to obtain the particle size data of the battery-grade sodium carbonate sample to be tested.

[0028] Specifically, in step S1, the alcohol-based chemical reagent includes one or more of anhydrous ethanol, anhydrous isopropanol, and anhydrous n-butanol.

[0029] Specifically, in step S1, the stirring time is 30~60 min (e.g., 30 min, 33 min, 36 min, 40 min, 43 min, 45 min, 48 min, 50 min, 53 min, 57 min, 60 min), and the stirring speed is 50~200 r / min (e.g., 50 r / min, 70 r / min, 90 r / min, 100 r / min, 120 r / min, 140 r / min, 150 r / min, 160 r / min, 180 r / min, 200 r / min).

[0030] It should be noted that this invention first uses anhydrous ethanol, anhydrous isopropanol, and anhydrous n-butanol as dispersion media to reduce the solubility of sodium carbonate. By pre-preparing a saturated sodium carbonate alcohol solution, a solid-liquid dissolution equilibrium is formed, completely eliminating the problems of particle corrosion and small particle size caused by the slight solubility of sodium carbonate, thus ensuring the accuracy of the test results. During the stirring process, it is necessary to ensure that the stirring speed and stirring time are sufficient to reach a saturated state of the solution.

[0031] Specifically, in step S2, the mass fraction of sodium oleate in the dispersant solution is 0.05~0.75% (e.g., 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%). More preferably, the mass fraction of sodium oleate in the dispersant solution is 0.1~0.5%. More preferably, the mass fraction is 0.25~0.5%.

[0032] It should be noted that this invention uses sodium oleate as a dispersant. As an anionic surfactant, it can quickly adsorb onto the surface of sodium carbonate particles, improving the wettability of the particles in alcohol-based solvents. Simultaneously, it generates a steric hindrance effect, effectively preventing the reformation of aggregates. Furthermore, it does not react with sodium carbonate, thus not damaging the particle structure, making it more suitable for the characteristics of battery-grade sodium carbonate. The mass fraction of sodium oleate needs to be controlled within a reasonable range; too high a fraction can easily lead to supersaturation of sodium oleate in anhydrous ethanol, while too low a fraction will result in poor sample dispersion.

[0033] Specifically, in step S3, the amount of the battery-grade sodium carbonate sample to be tested added is 0.1~0.4 g (e.g., 0.1g, 0.15g, 0.2g, 0.25g, 0.3g, 0.35g, 0.4g).

[0034] Specifically, in step S3, the amount of the dispersant solution used is 10~60 mL (e.g., 10 mL, 15 mL, 20 mL, 25 mL, 30 mL, 35 mL, 40 mL, 45 mL, 50 mL, 55 mL, 60 mL).

[0035] It should be noted that the amount of dispersant solution should be adjusted according to the amount of battery-grade sodium carbonate sample to be tested. Too high a sample concentration will cause agglomeration, preventing the formation of a uniform dispersion system; too low a sample concentration will prevent the effective light-blocking range required by the laser particle size analyzer from being achieved.

[0036] Specifically, in step S4, the ultrasound time is 0.05~6 min (e.g., 0.05 min, 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min, 4 min, 4.5 min, 5 min, 5.5 min, 6 min), and the ultrasound power is 50~300W (e.g., 50 W, 70 W, 100 W, 130 W, 160 W, 190 W, 210 W, 240 W, 270 W, 300 W). More preferably, the ultrasound time is 1~5 min.

[0037] It should be noted that in step S4, the ultrasonic dispersion time needs to be controlled to avoid the particles breaking down due to excessive time or the agglomeration not being broken down due to insufficient time.

[0038] Specifically, in step S5, the operating parameters of the laser particle size analyzer are as follows: the stirring speed of the instrument is adjusted to 100~500 r / min (e.g., 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min), and the sample occlusion is controlled to 6~12% (e.g., 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%).

[0039] It should be noted that in step S5, the stirring speed of the instrument should be adjusted to a moderate level to avoid particle breakage due to excessive speed and agglomeration due to excessively slow speed. After adjusting the parameters of the laser particle size analyzer, wait for the instrument display to stabilize, and perform 2 to 4 consecutive measurements. Take the average value of the multiple measurement results as the final particle size data.

[0040] It should be noted that battery-grade sodium carbonate has extremely small particle size, typically D50 of 2-5 μm. When conventionally dispersed by dry airflow, these fine particles easily adhere to the wall, resulting in insufficient dispersion and significantly inaccurate particle size data with poor repeatability. This invention employs wet dispersion detection, combining sodium oleate dispersant and alcohol-based reagents. This effectively solves the problems of inaccurate detection data and poor repeatability caused by the small particle size and tendency to agglomerate of battery-grade sodium carbonate. It avoids fine particles adhering to the wall, ensures sufficient particle dispersion, and provides detection data that accurately reflects the true particle size, with good repeatability and small error.

[0041] To more clearly describe the present invention, the following examples and comparative examples are provided. All examples and comparative examples used the same batch of battery-grade sodium carbonate samples (basic particle size reference: D50 approximately 2~5 μm) to ensure consistency of detection conditions and comparability of results.

[0042] Example 1 A method for particle size detection of sodium carbonate raw material for sodium ion cathode materials includes the following steps: S1. Add an excess of the battery-grade sodium carbonate sample to be tested to anhydrous ethanol, and stir continuously at a stirring speed of 150 r / min for 30 min to ensure that the sodium carbonate is fully dissolved and reaches saturation. Let stand for 30 min to allow the undissolved particles to settle completely, and take the clear liquid from the top layer for later use. S2. Weigh 400g of the saturated sodium carbonate anhydrous ethanol supernatant from step S1, add 1.0g of sodium oleate, and stir until the sodium oleate is completely dissolved to prepare a dispersant solution with a sodium oleate mass fraction of 0.25%. S3. Add 30 mL of the dispersant solution from step S2 to a beaker, weigh 0.2 g of the battery-grade sodium carbonate sample to be tested, slowly add it to the beaker, and stir until homogeneous. S4. Place the sample suspension from step S3 into an ultrasonic disperser, set the ultrasonic power to 200W, and ultrasonically disperse for 1 minute. S5. Slowly inject the sample suspension processed in step S4 into the sample cell of the laser particle size analyzer. Set the instrument stirring speed to 500 r / min and control the sample occlusion to 6-12%. After the instrument display stabilizes, perform three consecutive tests and take the average of the three test results as the final particle size data.

[0043] Example 2 A method for particle size detection of sodium carbonate raw material for sodium ion cathode materials includes the following steps: S1. Add an excess of the battery-grade sodium carbonate sample to be tested to anhydrous isopropanol, and stir continuously at a stirring speed of 150 r / min for 30 min to ensure that the sodium carbonate is fully dissolved and reaches saturation. Let stand for 30 min to allow undissolved particles to settle completely, and take the clear liquid from the top layer for later use. S2. Weigh 400g of the saturated sodium carbonate anhydrous isopropanol supernatant from step S1, add 1.0g of sodium oleate, and stir until the sodium oleate is completely dissolved to prepare a dispersant solution with a sodium oleate mass fraction of 0.25%. S3. Add 30 mL of the dispersant solution from step S2 to a beaker, weigh 0.2 g of the battery-grade sodium carbonate sample to be tested, slowly add it to the beaker, and stir until homogeneous. S4. Place the sample suspension from step S3 into an ultrasonic disperser, set the ultrasonic power to 200W, and ultrasonically disperse for 1 minute. S5. Slowly inject the sample suspension processed in step S4 into the sample cell of the laser particle size analyzer. Set the instrument stirring speed to 500 r / min and control the sample occlusion to 6-12%. After the instrument display stabilizes, perform three consecutive tests and take the average of the three test results as the final particle size data.

[0044] Example 3 The preparation process of Example 3 is largely the same as that of Example 1, except that anhydrous ethanol is replaced with anhydrous n-butanol in Example 3.

[0045] Example 4 The preparation process of Example 4 is largely the same as that of Example 1, except that the amount of sodium oleate added in Example 4 is 0.2g, and a dispersant solution with a sodium oleate mass fraction of 0.05% is prepared.

[0046] Example 5 The preparation process of Example 5 is largely the same as that of Example 1, except that the amount of sodium oleate added in Example 5 is 2.0 g, and a dispersant solution with a sodium oleate mass fraction of 0.5% is prepared.

[0047] Example 6 The preparation process of Example 6 is largely the same as that of Example 1, except that the amount of sodium oleate added in Example 6 is 3g, and a dispersant solution with a sodium oleate mass fraction of 0.75% is prepared.

[0048] Example 7 The preparation process of Example 7 is largely the same as that of Example 1, except that the ultrasonic dispersion time in Example 7 is 0.5 min.

[0049] Example 8 The preparation process of Example 8 is largely the same as that of Example 1, except that the ultrasonic dispersion time in Example 8 is 5 min.

[0050] Example 9 The preparation process of Example 9 is largely the same as that of Example 1, except that the ultrasonic dispersion time in Example 9 is 6 min.

[0051] Comparative Example 1 A method for particle size determination of sodium carbonate raw material for sodium ion cathode materials includes the following detection steps: S1. Add an excess of the battery-grade sodium carbonate sample to be tested to anhydrous ethanol, and stir continuously at a stirring speed of 150 r / min for 30 min to ensure that the sodium carbonate is fully dissolved and reaches saturation. Let stand for 30 min to allow the undissolved particles to settle completely, and take the clear liquid from the top layer for later use. S2. Add 30 mL of the saturated sodium carbonate anhydrous ethanol solution from step S1 to a beaker. Weigh 0.2 g of the battery-grade sodium carbonate sample to be tested, slowly add it to the beaker, and stir until homogeneous. S3. Place the sample suspension from step S2 into an ultrasonic disperser, set the ultrasonic power to 200W, and ultrasonically disperse for 1 minute. S4. Slowly inject the sample suspension processed in step S3 into the sample cell of the laser particle size analyzer. Set the instrument stirring speed to 500 r / min and control the sample occlusion to 6-12%. After the instrument display stabilizes, perform three consecutive tests and take the average of the three test results as the final particle size data.

[0052] Comparative Example 2 A method for particle size determination of sodium carbonate raw material for sodium ion cathode materials includes the following detection steps: S1. Weigh 400g of anhydrous ethanol solution, add 1.0g of sodium oleate, stir until the sodium oleate is completely dissolved, and prepare a dispersant solution with a sodium oleate mass fraction of 0.25%. S2. Add 30 mL of the dispersant solution from step S1 to a beaker, weigh 0.2 g of the battery-grade sodium carbonate sample to be tested, slowly add it to the beaker, and stir until homogeneous. S3. Place the sample suspension from step S2 into an ultrasonic disperser, set the ultrasonic power to 200W, and ultrasonically disperse for 1 minute. S4. Slowly inject the sample suspension processed in step S3 into the sample cell of the laser particle size analyzer. Set the instrument stirring speed to 500 r / min and control the sample occlusion to 6-12%. After the instrument display stabilizes, perform three consecutive tests and take the average of the three test results as the final particle size data.

[0053] Comparative Example 3 Comparative Example 3 uses a dry detection method. The battery-grade sodium carbonate sample to be tested is added to a dry particle size analyzer for particle size detection. The test is performed three times consecutively, and the average value of the three test results is taken as the final particle size data.

[0054] Performance testing The particle size detection results of Examples 1-9 and Comparative Examples 1-3 were recorded and are shown in Table 1.

[0055] Table 1. Detection results of Examples 1-9 and Comparative Examples 1-3

[0056] As can be seen from Table 1: In Examples 1-9, the detection method described in this invention demonstrates high accuracy. Referring to Examples 1-3 and... Figure 1 , Figure 2 The particle size distribution diagram shows that different alcohol-based reagents can achieve uniform dispersion of the material, meeting the testing requirements.

[0057] The detection results from Example 1 and Comparative Example 1, and Figure 1 and Figure 3 The particle size distribution diagram shows that, in Comparative Example 1, no sodium oleate was added, resulting in agglomeration of the battery-grade sodium carbonate sample, leading to an overestimation of the measured value. This indicates that the use of sodium oleate as a dispersant in this invention effectively solves the agglomeration problem of battery-grade sodium carbonate, and the particle size detection is closer to the true value.

[0058] The detection results from Example 1 and Comparative Example 2, and Figure 1 and Figure 4 The particle size distribution diagram shows that in Comparative Example 2, a saturated sodium carbonate alcohol solution was not prepared in advance. Therefore, the battery-grade sodium carbonate sample dissolved only slightly in anhydrous ethanol, resulting in a smaller particle size. This demonstrates that the method of preparing a saturated sample solution in this invention can effectively inhibit sample dissolution and ensure the accuracy of the detection results.

[0059] As can be seen from the detection results of Example 1 and Comparative Example 3, the wet method used in this invention to detect the particle size of battery-grade sodium carbonate is more accurate than the dry method.

[0060] The test results from Examples 1 and 4-6 show that controlling the mass fraction of sodium oleate in the dispersant solution to 0.1-0.5% results in better dispersion and more accurate test results.

[0061] As can be seen from the detection results of Examples 1 and 7-9, the detection results are more accurate when the ultrasound time is controlled between 1 and 5 minutes.

[0062] In summary, this invention employs wet dispersion detection, combined with sodium oleate dispersant and alcohol-based reagents, effectively solving the problems of inaccurate detection data and poor repeatability caused by the small particle size and easy agglomeration of battery-grade sodium carbonate; it avoids fine particles sticking to the wall, ensures that the particles are fully dispersed, and the detection data can reflect the true particle size, with good repeatability and small error.

[0063] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials, characterized in that, Includes the following steps: S1. Add an excess of the battery-grade sodium carbonate sample to be tested to the alcohol-based chemical reagent, stir thoroughly, let stand for separation, and take the supernatant to obtain a saturated sodium carbonate alcohol solution. S2. Add sodium oleate to the saturated sodium carbonate alcohol solution obtained in step S1, and stir until the sodium oleate is completely dissolved to prepare a dispersant solution; S3. Weigh the battery-grade sodium carbonate sample to be tested, add it to the dispersant solution obtained in step S2, stir evenly, and obtain a sample suspension. S4. Place the sample suspension from step S3 in an ultrasonic disperser and perform ultrasonic dispersion. S5. The sample suspension processed in step S4 is injected into the sample cell of the laser particle size analyzer for particle size detection to obtain the particle size data of the battery-grade sodium carbonate sample to be tested.

2. The method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S1, the alcohol-based chemical reagent includes one or more of anhydrous ethanol, anhydrous isopropanol, and anhydrous n-butanol.

3. The method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S1, the stirring time is 30~60 min and the stirring speed is 50~200 r / min.

4. The method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S2, the mass fraction of sodium oleate in the dispersant solution is 0.05~0.75%.

5. The method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S2, the mass fraction of sodium oleate in the dispersant solution is 0.1~0.5%.

6. A method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S3, the amount of the battery-grade sodium carbonate sample to be tested added is 0.1~0.4 g.

7. A method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S3, the amount of the dispersant solution used is 10~60 mL.

8. A method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S4, the ultrasound time is 0.5~6 min and the ultrasound power is 50~300 W.

9. A method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S5, the operating parameters of the laser particle size analyzer are as follows: adjust the stirring speed of the instrument to 100~500 r / min, and control the sample occlusion to 6~12%.

10. The method for detecting the particle size of sodium carbonate raw material for sodium ion cathode materials according to claim 1, characterized in that, In step S5, a laser particle size analyzer is used to continuously detect the particle size 2 to 4 times, and the average value of the multiple detection results is taken as the final particle size data.

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