A lead and / or lead oxide powder dispersion, a method for producing the same, and a method for detecting the particle size distribution of a lead and / or lead oxide powder

Abstract

This invention relates to the field of lead-acid battery technology, and more particularly to a lead and / or lead oxide powder dispersion, its preparation method, and a method for detecting the particle size distribution of lead and / or lead oxide powder. The lead and / or lead oxide powder dispersion comprises lead and / or lead oxide powder, sodium tripolyphosphate, ethanol, and water, wherein the volume ratio of ethanol to water is 1:0.8-4, the mass ratio of sodium tripolyphosphate to the total volume of ethanol and water is 0.2-0.9 g:30 mL, and the total mass ratio of lead and / or lead oxide powder to the total volume of ethanol and water is 1-5 g:30 mL. The powder particles in this lead and / or lead oxide powder dispersion are uniformly and stably dispersed, which can be used to accurately determine the particle size distribution of lead powder. This allows for the screening of lead powder with stable particle size in the preparation of lead-acid batteries, ensuring consistent performance. It also provides a reference for adjusting the process parameters of lead powder preparation, ensuring that lead powder produced by different equipment has the desired particle size.

Description

Technical Field

[0001] This invention relates to the field of lead-acid battery technology, and in particular to a lead and / or lead oxide powder dispersion, a method for preparing the same, and a method for detecting the particle size distribution of lead and / or lead oxide powder. Background Technology

[0002] One of the key factors affecting the performance of lead-acid batteries is the active material on the plates. This active material is prepared by mixing lead powder with additives, sulfuric acid, and water. The activity level of the lead powder determines the discharge performance and cycle life of the lead-acid battery.

[0003] Currently, lead powder is mainly produced through the Paton pot process and ball milling. These two methods produce lead powder containing 20%–30% unoxidized lead, forming a mixture of lead and lead oxide, which is the lead powder used in lead-acid batteries. Current lead powder production primarily controls its apparent density, oxidation content, and moisture content, without specifying requirements for particle size. However, particle size is a key factor affecting lead-acid battery performance and a major cause of poor performance consistency. Current methods for detecting lead powder particle size distribution mainly use water as a dispersion medium, dispersing the lead powder in water and testing it with a laser particle size analyzer. However, due to the severe agglomeration problem of lead powder, the test data has significant deviations, resulting in unstable and inaccurate test results, making it difficult to guarantee the performance consistency of lead-acid batteries. Summary of the Invention

[0004] This invention provides a lead and / or lead oxide powder dispersion, a method for preparing the same, and a method for detecting the particle size distribution of lead and / or lead oxide powder. The powder particles in the lead and / or lead oxide powder dispersion are uniformly and stably dispersed, which can be used to accurately determine the particle size distribution of lead powder, and the test results are stable.

[0005] This invention provides a lead and / or lead oxide powder dispersion, comprising lead and / or lead oxide powder, sodium tripolyphosphate, ethanol, and water.

[0006] The volume ratio of ethanol to water is 1:0.8-4.

[0007] The mass ratio of sodium tripolyphosphate to the total volume of ethanol and water is 0.2-0.9 g:30 mL.

[0008] The ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 1-5 g: 30 mL.

[0009] Optionally, the volume ratio of ethanol to water is 1:1-3.5.

[0010] Optionally, the mass ratio of the sodium tripolyphosphate to the total volume of ethanol and water is 0.3-0.8 g:30 mL.

[0011] Optionally, the ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 2-4 g: 30 mL.

[0012] Optionally, the ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 3 g: 30 mL.

[0013] The present invention also provides a method for preparing a lead and / or lead oxide powder dispersion as described in any of the above technical solutions, comprising the following steps:

[0014] Lead and / or lead oxide powder is mixed with sodium tripolyphosphate, ethanol and water to obtain a dispersion of lead and / or lead oxide powder.

[0015] Optionally, the preparation method specifically includes the following steps:

[0016] A) Mix lead and / or lead oxide powder with sodium tripolyphosphate and ethanol to obtain an ethanol dispersion of lead and / or lead oxide.

[0017] B) Mix the ethanol dispersion of lead and / or lead oxide with water to obtain the lead and / or lead oxide powder dispersion.

[0018] The present invention also provides a method for detecting the particle size distribution of lead and / or lead oxide powder, comprising the following steps:

[0019] The lead and / or lead oxide powder dispersion prepared by any one of the above technical solutions or by any one of the above technical solutions is placed in a laser particle size analyzer to detect the particle size distribution and obtain the particle size distribution results of the lead and / or lead oxide powder.

[0020] Optionally, the parameters of the laser particle size analyzer include: detection mode is general mode, sample material refractive index is 2.01, dispersion medium refractive index is selected as water refractive index 1.333, and analysis range is 0.1-750 µm.

[0021] Optionally, before detecting the particle size distribution, the lead and / or lead oxide powder dispersion is subjected to ultrasonication at a frequency of 25-35 Hz for 1-2 min.

[0022] Compared with existing technologies, this invention has the following beneficial effects: This invention is the first to apply sodium tripolyphosphate to the dispersion of lead and / or lead oxide. It can eliminate bridging flocculation caused by polyvalent cations by imparting a high negative charge to the particle surface. Combined with hydrophilicity and weak steric hindrance, it achieves uniform and stable particle dispersion. The addition of ethanol further ensures the uniform distribution and maintenance of lead and / or lead oxide particles. The resulting lead and / or lead oxide powder dispersion exhibits stable particle dispersion. Particle size distribution testing of this dispersion yields accurate results, providing a basis for screening lead powder with stable particle size in the preparation of lead-acid batteries, ensuring consistent performance. It also provides a reference for adjusting lead powder preparation process parameters to ensure that lead powder produced by different equipment has the required particle size.

[0023] Experimental results show that when the lead and / or lead oxide powder dispersion provided by this invention is used to test particle size distribution, the obtained particle size is smaller, and the results of multiple tests are not significantly different, indicating that the lead and / or lead oxide powder particles can be dispersed more uniformly and stably. In contrast, when water and sodium hexametaphosphate aqueous solution are used as dispersion media, the particle agglomeration is severe, and the test results are unstable. Detailed Implementation

[0024] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0025] This invention provides a lead and / or lead oxide powder dispersion, comprising lead and / or lead oxide powder, sodium tripolyphosphate, ethanol, and water. The volume ratio of ethanol to water is 1:0.8-4, the mass ratio of sodium tripolyphosphate to the total volume of ethanol and water is 0.2-0.9 g:30 mL, and the total mass ratio of lead and / or lead oxide powder to the total volume of ethanol and water is 1-5 g:30 mL. In this invention, unless otherwise specified, ethanol refers to anhydrous ethanol; lead and / or lead oxide powder can be understood as one of lead oxide powder, a powder of lead and lead oxide mixture (i.e., lead oxide-coated lead powder), where lead oxide includes various single lead oxides or mixtures such as lead monoxide, lead dioxide, and lead tetroxide. In the embodiments of this invention, the dispersed lead powder is a mixture of lead and lead oxide. Experimental results show that the dispersion medium combination of sodium tripolyphosphate dispersant and ethanol and water can disperse the lead and lead oxide mixture powder, thus also uniformly dispersing the lead or lead oxide powder. In this invention, the sodium tripolyphosphate eliminates bridging flocculation caused by polyvalent cations by imparting a high negative charge to the surface of the powder particles, and further enhances the uniform and stable dispersion of the particles by providing hydrophilicity and weak steric hindrance; the addition of ethanol can further disperse the powder particles and maintain a uniform distribution.

[0026] In some embodiments of the present invention, the volume ratio of ethanol to water is 1:1-3.5, specifically 1:1, 1:1.5, 1:2, 1:2.5, 1:3.3, 1:3.5, etc. In the present invention, the above-mentioned ratio range ensures uniform dispersion of powder particles while avoiding the problem of unstable test results caused by excessive ethanol evaporation.

[0027] In some embodiments of the present invention, the total volume ratio of sodium tripolyphosphate to ethanol and water is 0.3-0.8 g:30 mL, specifically 0.3 g:30 mL, 0.5 g:30 mL, 0.8 g:30 mL, etc.

[0028] In some embodiments of the present invention, the ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 2-4 g: 30 mL, specifically 1 g: 30 mL, 2 g: 30 mL, 3 g: 30 mL, 4 g: 30 mL, 5 g: 30 mL, etc.

[0029] The present invention also provides a method for preparing a lead and / or lead oxide powder dispersion as described in any of the above technical solutions, comprising the following steps:

[0030] Lead and / or lead oxide powder is mixed with sodium tripolyphosphate, ethanol and water to obtain a dispersion of lead and / or lead oxide powder.

[0031] In some embodiments of the present invention, the preparation method specifically includes the following steps:

[0032] A) Lead and / or lead oxide powder is mixed with sodium tripolyphosphate and ethanol to obtain an ethanol dispersion of lead and / or lead oxide.

[0033] B) Mix the ethanol dispersion of lead and / or lead oxide with water to obtain the lead and / or lead oxide powder dispersion.

[0034] The inventors discovered in their experiments that the order in which ethanol and water are added has a certain impact on the dispersibility of the powder. Compared to adding water first, when ethanol is added first, the agglomeration of the powder in the resulting dispersion is reduced, and the dispersion is more uniform. This may be because ethanol can better wet the powder surface, reduce hard agglomeration caused by van der Waals forces between particles, and make the particles easier to disperse in water.

[0035] In some embodiments of the present invention, the mixing in steps A) and B) is to stir and mix for 2-4 minutes, specifically 2 minutes, 3 minutes, 4 minutes, etc.

[0036] The present invention also provides a method for detecting the particle size distribution of lead and / or lead oxide powder, comprising the following steps:

[0037] The lead and / or lead oxide powder dispersion prepared by any one of the above technical solutions or by any one of the above technical solutions is placed in a laser particle size analyzer to detect the particle size distribution and obtain the particle size distribution results of the lead and / or lead oxide powder.

[0038] This invention does not impose any specific limitations on the parameters of the laser particle size analyzer. Those skilled in the art can select the parameters according to the specific laser particle size analyzer used. In this embodiment, the laser particle size analyzer used is a BT-9300HT model; the parameters of the laser particle size analyzer include: detection mode is general mode, sample material refractive index is 2.01, the refractive index of the dispersion medium is selected as water (1.333), and the analysis range is 0.1-750 µm.

[0039] In some embodiments of the present invention, before detecting the particle size distribution, the lead and / or lead oxide powder dispersion is ultrasonicated; the ultrasonic frequency is 25-35 Hz, specifically 25 Hz, 28 Hz, 30 Hz, 33 Hz, 35 Hz, etc.; the ultrasonic time is 1-2 min, specifically 1 min, 1.5 min, 2 min, etc. In this step, the ultrasonication is a built-in function of the laser particle size analyzer. Performing ultrasonication before detection can further ensure uniform dispersion and prevent the lead oxide layer from peeling off, thus ensuring the accuracy of the test results.

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] The particle size distribution of lead powder produced from five lead powder mills of the same model was tested using the following steps. The lead powder samples were labeled as 1#, 2#, 3#, 4# and 5#, respectively.

[0043] (1) Add 3 g of lead powder to be tested, 0.5 g of sodium tripolyphosphate and 10 mL of ethanol to a beaker and stir for 2 min to obtain lead powder ethanol dispersion.

[0044] (2) Add 20 mL of water to the lead powder ethanol dispersion and stir for 2 min to obtain the lead powder dispersion.

[0045] (3) After preheating the laser particle size analyzer, set the sample material refractive index to 2.01, the dispersion medium refractive index to 1.333, the analysis range to 0.1-750 µm, and the dispersion medium to pure water. Place the lead powder dispersion in a BT-9300HT laser particle size analyzer, use a frequency of 30 Hz, and ultrasonically disperse for 1 min before particle size distribution detection. Perform the detection three times and take the average value.

[0046] Three samples of lead powder produced by each lead powder machine were taken and their particle size distribution was tested according to the method described above. The median particle size (D) was then given. 50 The average of the test results for the three samples ( / µm) was taken as the final result, and the range (i.e., the maximum value minus the minimum value) was calculated to evaluate the test stability. The results are shown in Table 1.

[0047] Example 2

[0048] The particle size distribution of lead powder produced by five lead powder machines of the same model was tested according to the method in Example 1, with the only difference being that the mass of sodium tripolyphosphate was 0.3 g.

[0049] Example 3

[0050] The particle size distribution of lead powder produced by five lead powder machines of the same model was tested according to the method in Example 1, with the only difference being that the mass of sodium tripolyphosphate was 0.8 g.

[0051] Example 4

[0052] The particle size distribution of lead powder produced by the five lead powder machines of the same model were tested according to the method in Example 1, with the only difference being that the lead powder dispersion was prepared as follows:

[0053] (1) Add 3 g of lead powder to be tested, 0.5 g of sodium tripolyphosphate and 20 mL of water to a beaker and stir for 2 min to obtain a lead powder aqueous dispersion.

[0054] (2) Add 10 mL of anhydrous ethanol to the lead powder aqueous dispersion and stir for 2 min to obtain the lead powder dispersion.

[0055] Example 5

[0056] The particle size distribution of lead powder produced by five lead powder machines of the same model was tested according to the method in Example 1, with the only difference being that the amount of ethanol used was 15 mL and the amount of water used was 15 mL.

[0057] Example 6

[0058] The particle size distribution of lead powder produced by five lead powder machines of the same model was tested according to the method in Example 1, with the only difference being that the amount of ethanol used was 7 mL and the amount of water used was 23 mL.

[0059] Example 7

[0060] The particle size distribution of lead powder produced by five lead powder machines of the same model was tested according to the method in Example 1, with the only difference being that the mass of the lead powder was 2 g.

[0061] Example 8

[0062] The particle size distribution of lead powder produced by five lead powder machines of the same model was tested according to the method in Example 1, with the only difference being that the mass of the lead powder was 4 g.

[0063] Comparative Example 1

[0064] The particle size distribution of lead powder produced by the five lead powder machines of the same model were tested according to the method in Example 1, with the only difference being that the lead powder dispersion was prepared as follows:

[0065] Mix 3 g of lead powder with 30 mL of water for 2 min to obtain a lead powder dispersion.

[0066] Comparative Example 2

[0067] The particle size distribution of lead powder produced by the five lead powder machines of the same model were tested according to the method in Example 1, with the only difference being that the lead powder dispersion was prepared as follows:

[0068] 3 g lead powder, 0.5 g sodium hexametaphosphate and 30 mL water were stirred and mixed for 2 min to obtain lead powder dispersion.

[0069] Comparative Example 3

[0070] The particle size distribution of lead powder produced by the five lead powder machines of the same model were tested according to the method in Example 1, with the only difference being that the lead powder dispersion was prepared as follows:

[0071] 3 g lead powder, 0.5 g sodium tripolyphosphate and 30 mL water were stirred and mixed for 2 min to obtain lead powder dispersion.

[0072] Table 1. D obtained from particle size distribution tests in Examples 1-7 and Comparative Examples 1-3 50

[0073]

[0074] As can be seen from Table 1, when testing the particle size distribution of lead powder prepared with the same equipment, the dispersion obtained using the method of this invention yields D... 50 Both are much smaller than the D values ​​obtained when using pure water and sodium hexametaphosphate aqueous solution as the dispersion medium. 50 This indicates that the lead and / or lead oxide powder particles in the lead and / or lead oxide powder dispersion provided by the present invention can be dispersed more uniformly, while when water and sodium hexametaphosphate aqueous solution are used as dispersion media, particle agglomeration is still relatively serious. Furthermore, according to the test results of Examples 1 and 4, keeping other conditions constant, adjusting the order of adding ethanol and water during the preparation of the lead powder dispersion will also have a certain impact on the dispersion, thus affecting the test results, indicating that adding ethanol first can better disperse the lead powder.

[0075] The range of the test results in Table 1 is shown in Table 2:

[0076] Table 2. D obtained from particle size distribution tests in Examples 1-7 and Comparative Examples 1-3 50 range

[0077]

[0078] As can be seen from the data in Table 2, compared with using pure water as the dispersion medium and no dispersant, sodium hexametaphosphate, or sodium tripolyphosphate as the dispersant, the dispersion provided by the present invention has a smaller range during the test process, that is, the results of each test are not much different, the test stability is high, and the results are more accurate. At the same time, according to the test results of Examples 1 and 4, it can be seen that keeping other conditions unchanged, changing the order of adding ethanol and water will affect the dispersion stability of particles in the dispersion.

[0079] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A dispersion of lead and / or lead oxide powder, comprising lead and / or lead oxide powder, sodium tripolyphosphate, ethanol, and water. in, The volume ratio of ethanol to water is 1:0.8-4. The mass ratio of sodium tripolyphosphate to the total volume of ethanol and water is 0.2-0.9 g:30 mL. The ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 1-5 g: 30 mL.

2. The lead and / or lead oxide powder dispersion according to claim 1, characterized in that, The volume ratio of ethanol to water is 1:1-3.

5.

3. The lead and / or lead oxide powder dispersion according to claim 1, characterized in that, The mass ratio of the sodium tripolyphosphate to the total volume of ethanol and water is 0.3-0.8 g:30 mL.

4. The lead and / or lead oxide powder dispersion according to any one of claims 1-3, characterized in that, The ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 2-4 g: 30 mL.

5. The lead and / or lead oxide powder dispersion according to claim 4, characterized in that, The ratio of the total mass of the lead and / or lead oxide powder to the total volume of ethanol and water is 3 g: 30 mL.

6. A method for preparing a lead and / or lead oxide powder dispersion according to any one of claims 1-5, comprising the following steps: Lead and / or lead oxide powder is mixed with sodium tripolyphosphate, ethanol and water to obtain a dispersion of lead and / or lead oxide powder.

7. The preparation method according to claim 6, characterized in that, The preparation method specifically includes the following steps: A) Lead and / or lead oxide powder is mixed with sodium tripolyphosphate and ethanol to obtain an ethanol dispersion of lead and / or lead oxide. B) Mix the ethanol dispersion of lead and / or lead oxide with water to obtain the lead and / or lead oxide powder dispersion.

8. A method for detecting the particle size distribution of lead and / or lead oxide powder, comprising the following steps: The lead and / or lead oxide powder dispersions according to any one of claims 1-5 or the lead and / or lead oxide powder dispersions prepared by the preparation method according to claim 6 or 7 are placed in a laser particle size analyzer to detect the particle size distribution and obtain the particle size distribution results of the lead and / or lead oxide powders.

9. The particle size distribution detection method according to claim 8, characterized in that, The parameters of the laser particle size analyzer include: detection mode is general mode, sample material refractive index is 2.01, dispersion medium refractive index is selected as water refractive index 1.333, and analysis range is 0.1-750 µm.

10. The particle size distribution detection method according to claim 8 or 9, characterized in that, Before detecting the particle size distribution, the lead and / or lead oxide powder dispersion is subjected to ultrasonication at a frequency of 25-35 Hz for 1-2 min.

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