Methods for measuring particle size and morphology

Abstract

The present application provides a method for measuring particle size and morphology, which belongs to the technical field of process mineralogy. The present application analyzes the particle size based on the centroid of the particle in combination with geometric and statistical parameters, and simultaneously analyzes and characterizes the morphological characteristics of the particles. The specific particle size measurement result is an equivalent radius result based on the centroid, which can directly reflect the overall size of the particle. Furthermore, the morphological characteristic result is based on the centroid distance statistics, which can quantify the irregularity of the particle, such as roundness, aspect ratio, roughness, etc.; the test method is measured on a two-dimensional plane, and its measurement results are not affected by the selected direction, and can provide accurate particle size and morphology characterization for particles with complex morphologies (such as dendritic or porous structures), providing a reliable test method for the analysis of complex particle systems (such as geological sediments, industrial powders or biological particles).

Description

Technical Field

[0001] The invention relates to the technical field of process mineralogy, and in particular to a method for measuring particle size and morphology. Background Art

[0002] Particle size measurement, a core analytical technique in materials science, chemical engineering, pharmaceuticals, mining, and other fields, has a decisive impact on material performance evaluation and process optimization. Particle size characteristics directly determine key performance indicators such as mechanical strength, flow characteristics, dissolution behavior, and optical properties. However, traditional measurement methods often exhibit significant limitations when dealing with unusual particle morphologies, such as non-spherical, porous, fibrous, and agglomerated particles.

[0003] Current mainstream particle size characterization methods suffer from the following major issues: First, their adaptability is limited. For example, the area equivalent circle radius method, while computationally simple, is only applicable to approximately spherical particles and lacks the ability to characterize complex morphologies. The minimum circumscribed circle radius method is limited to the analysis of specialized samples. While theoretically feasible, the Fourier fitting method is computationally complex and requires high-precision morphological data, making its practical application extremely limited. Second, the characterization dimension is limited. Existing methods generally only provide information on particle size distribution and are unable to quantitatively describe important morphological parameters such as particle roundness, aspect ratio, and fractal characteristics. Furthermore, they currently rely primarily on manual visual assessment, which is not only highly subjective but also difficult to standardize. Third, measurement errors are significant and strongly dependent on orientation. For example, methods such as Feret diameter and projected area equivalent diameter are significantly affected by particle orientation. The same particle can produce significantly different measurement results when placed in different orientations, resulting in significant morphological distortion. Using equivalent radius (such as the area equivalent circle) cannot accurately reflect the true morphological characteristics of irregular particles such as dendritic and porous structures. Fourth, the sample preparation interference is significant. Human factors such as particle agglomeration, uneven dispersion or cutting direction deviation during the sample preparation process will introduce significant errors, causing the measurement results to deviate from the true value.

[0004] Existing measurement technologies are unable to accurately characterize the size and morphology of particles with complex morphologies, such as dendritic or porous structures. This technical bottleneck severely restricts research progress and industrial applications in cutting-edge fields such as new energy materials, biomedicine, and advanced ceramics. Summary of the Invention

[0005] In view of the technical problems existing in the background technology, the present application provides a method for measuring particle size and morphology, aiming to solve the problem that existing measurement technology can hardly provide accurate particle size and morphology characterization for particles with complex morphology.

[0006] The present application provides a method for measuring particle size and morphology, comprising the following steps:

[0007] S1. Take the particles to be tested and perform ultrasonic dispersion treatment, dry them, mix them with graphite particles, and then perform the first resin curing to obtain a cube-cured sample;

[0008] S2. The cube-shaped solidified sample was cut vertically along the midpoints of the four sides of the bottom square, and then cut along the horizontal midline to obtain two layers of cut blocks. The cut blocks were then placed with the test surface facing downward and the resin was cured for the second time to obtain multiple vertical cylindrical solidified samples.

[0009] S3. The bottom surfaces of the plurality of vertical cylindrical solidified samples were ground and polished, and carbon sprayed to obtain test samples;

[0010] S4. performing automatic mineralogical analysis on the test sample, and extracting particles from the test sample by a threshold segmentation method;

[0011] S5. Performing morphological closing operation on the holes of the particles in the test sample and processing the edges of the particles in the test sample in pixel units;

[0012] S6. Measure the total area of ​​the particle pixels of the particles in the test sample as A, and the micro-unit area of ​​the particle pixels as dA; and denote the centroid position coordinates of the particles in the test sample as Cn(Xn, Yn); where n = 1, 2, 3, ..., is the particle number;

[0013] Then Xn=1 / A* , Yn=1 / A* ;

[0014] S7. Calculate the centroid distance Rn.m of the particles in the test sample,

[0015] Then Rn.m=[(Xm-Xn) 2 +(Ym-Yn) 2 ] 0.5 ;

[0016] Where m = 1, 2, 3, ..., is the total number of distal contact points of the particles in the measured sample;

[0017] S8. Calculate the equivalent radius Rn of the particles in the test sample, then Rn=∑Rn.m / m;

[0018] S9. Calculate the particle size distribution rate W of the particles in the test sample, where W = ΣKn.md; where d is the particle size fraction corresponding to the particles in the test sample; where Kn.m is the centroid distance distribution coefficient of the particles in the test sample, Kn.m = (Rn.m / ΣRn.m)*Sn / ΣSn, where Sn is the exposed area of ​​the particles; and n = 1, 2, ..., M, where M is the sample number in particle fraction d;

[0019] S10. Calculate the average particle size Rn' of the particles in the test sample, where Rn'=∑Rn / n; wherein n=1, 2, ..., N, where N is the test particle number;

[0020] S11. Calculate the standard deviation SDn of the particle size in the test sample, then SDn=[(Rn.m-∑Rn.m / m) 2 ] 0.5 / (m-1); where n=1, 2, ..., N, and N is the test particle number;

[0021] S12. Calculate the overall particle size standard deviation SD of the particles in the test sample, then SD=[∑(Rn-Rn') 2 ] 0.5 / (n-1); where n = 1, 2, ..., N, and N is the test particle number;

[0022] S13. Calculate the maximum-to-minimum radius ratio rn: rn = (Rn.m)max / (Rn.m)min; where n = 1, 2, ..., N, where N is the test particle number.

[0023] In the technical solutions of the embodiments of this application, particle size is analyzed based on the centroid combined with geometric and statistical parameters, while also characterizing the particle's morphological characteristics. Specifically, the particle size measurement result is based on the equivalent radius of the centroid, which directly reflects the overall particle size. Furthermore, the morphological characteristic results are based on centroid distance statistics, which can quantify particle irregularities such as roundness, aspect ratio, and roughness. This test method measures on a two-dimensional plane, and its measurement results are unaffected by the selected orientation. It can also provide accurate characterization of the particle size and morphology for particles with complex morphologies (such as dendritic or porous structures).

[0024] In some embodiments, in step S1, the particle size of the graphite particles is 0.1 to 0.5 times the minimum particle size of the particles to be tested, and the total volume of the graphite particles is 2 to 5 times the total volume of the particles to be tested.

[0025] In this embodiment, by mixing graphite of a specific particle size with the particles to be measured in a certain proportion, adhesion between the particles can be reduced, thereby preventing erroneous measurement of the particle size.

[0026] In some embodiments, in step S2, the sampling of the surface to be tested of the cutting block includes an upper bottom surface and a lower bottom surface of the cube solidified sample, an upper surface and a lower surface of any side surface of the cube solidified sample, an upper surface and a lower surface of the "cross" cutting surface, and any surface of the cutting surface of the horizontal midline cutting.

[0027] In this embodiment, the above-mentioned method of selecting the side of the strip can effectively avoid the problem of uneven particle distribution caused by the deposition of particles during the sample preparation process, thereby ensuring that the sampling is representative.

[0028] In some embodiments, in step S3, the number of particles exposed on the exposed surface of the test sample is not less than 1000.

[0029] In this embodiment, as many test particles as possible make the final analysis test result more accurate.

[0030] In some embodiments, in step S5, the morphological closing operation is to fill the holes of the particles in the test sample so that the particles form connected domains.

[0031] In this embodiment, the particles in the test sample are filled to ensure the connectivity and integrity of the particle area, making the detection and analysis more accurate and more precise. If this operation is not performed, anomalies will occur when the distal contact point is subsequently determined, resulting in errors in the centroid distance.

[0032] In some embodiments, in step S7, the total number of distal contact points is the total number of intersections between rays emitted at equal angles from the centroid of the particle and the distal edge; the equal angles are 5-20°.

[0033] In this embodiment, the intersection of the ray and the farthest edge is used as the far-end contact point, which can better reflect the overall structure of the particle.

[0034] In some embodiments, in step S11, when the particle size standard deviation SDn of the particles in the test sample is ≈ 0, the particles in the test sample are close to spherical; when the particle size standard deviation SDn of the particles in the test sample is much greater than 0, the shape of the particles in the test sample is highly irregular.

[0035] In this embodiment, the data can reflect whether the particles are regular and can also evaluate the surface roughness.

[0036] In some embodiments, in step S12, when the overall particle size standard deviation SD of the particles in the test sample is ≈ 0, the morphology of the particles in the test sample is uniform; when the overall particle size standard deviation SD of the particles in the test sample is much greater than 0, the shapes of the particles in the test sample are highly irregular.

[0037] In this embodiment, the data can reflect the overall uniformity of the particles in the sample.

[0038] In some embodiments, in step S13, when rn=1, the particles in the test sample are cubic or spherical.

[0039] In this embodiment, the data can characterize the flatness and anisotropy of the particles.

[0040] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0042] Figure 1 Schematic diagram of cutting the cube solidified sample prepared in Example 1.

[0043] Figure 2 Schematic diagram of selecting the surface to be measured of the cutting block in Example 1.

[0044] Figure 3 A schematic diagram is selected for the distal contact point of a particle in Example 1.

[0045] Figure 4 These are pictures of the particles in Example 2 under a stereo microscope and automated mineralogy. DETAILED DESCRIPTION

[0046] The following embodiments of the technical solution of the present application are described in detail. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only used as examples and are not intended to limit the scope of protection of the present application.

[0047] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0049] To address the problem that existing measurement technologies are unable to accurately characterize the size and morphology of particles with complex morphologies, this application provides a method for measuring particle size and morphology. A two-dimensional particle size measurement method has been designed that effectively avoids directional dependence and embeds morphological information into the particle size measurement, making it suitable for analyzing complex particle systems (such as geological sediments, industrial powders, or biological particles). Based on the particle centroid, combined with geometric and statistical parameters, the particle size is analyzed and its morphological characteristics are simultaneously analyzed and characterized. Specifically, the particle size measurement result is an equivalent radius based on the centroid, which directly reflects the overall particle size. Furthermore, the morphological characteristics are based on centroid distance statistics, which can quantify particle irregularities such as roundness, aspect ratio, and roughness. This test method measures in a two-dimensional plane, and its results are unaffected by the selected direction. It can accurately characterize the size and morphology of particles with complex morphologies (such as dendritic or porous structures), providing a reliable test method for analyzing complex particle systems (such as geological sediments, industrial powders, or biological particles).

[0050] The present application provides a method for measuring particle size and morphology, comprising the following steps:

[0051] S1. Take the particles to be tested and perform ultrasonic dispersion treatment, dry them, mix them with graphite particles, and then perform the first resin curing to obtain a cube-cured sample;

[0052] S2. The cube-shaped solidified sample was cut vertically along the midpoints of the four sides of the bottom square, and then cut along the horizontal midline to obtain two layers of cut blocks. The cut blocks were then placed with the test surface facing downward and the resin was cured for the second time to obtain multiple vertical cylindrical solidified samples.

[0053] S3. The bottom surfaces of the plurality of vertical cylindrical solidified samples were ground and polished, and carbon sprayed to obtain test samples;

[0054] S4. performing automatic mineralogical analysis on the test sample, and extracting particles from the test sample by a threshold segmentation method;

[0055] S5. Performing morphological closing operation on the holes of the particles in the test sample and processing the edges of the particles in the test sample in pixel units;

[0056] S6. Measure the total area of ​​the particle pixels of the particles in the test sample as A, and the micro-unit area of ​​the particle pixels as dA; and denote the centroid position coordinates of the particles in the test sample as Cn(Xn, Yn); where n = 1, 2, 3, ..., is the particle number;

[0057] Then Xn=1 / A* , Yn=1 / A* ;

[0058] S7. Calculate the centroid distance Rn.m of the particles in the test sample,

[0059] Then Rn.m=[(Xm-Xn) 2 +(Ym-Yn) 2 ] 0.5 ;

[0060] Where m = 1, 2, 3, ..., is the total number of distal contact points of the particles in the measured sample;

[0061] S8. Calculate the equivalent radius Rn of the particles in the test sample, then Rn=∑Rn.m / m;

[0062] S9. Calculate the particle size distribution rate W of the particles in the test sample, where W = ΣKn.md; where d is the particle size fraction corresponding to the particles in the test sample; where Kn.m is the centroid distance distribution coefficient of the particles in the test sample, Kn.m = (Rn.m / ΣRn.m)*Sn / ΣSn, where Sn is the exposed area of ​​the particles; and n = 1, 2, ..., M, where M is the sample number in particle fraction d;

[0063] S10. Calculate the average particle size Rn' of the particles in the test sample, where Rn'=∑Rn / n; wherein n=1, 2, ..., N, where N is the test particle number;

[0064] S11. Calculate the standard deviation SDn of the particle size in the test sample, then SDn=[(Rn.m-∑Rn.m / m) 2 ] 0.5 / (m-1); where n=1, 2, ..., N, and N is the test particle number;

[0065] S12. Calculate the overall particle size standard deviation SD of the particles in the test sample, then SD=[∑(Rn-Rn') 2 ] 0.5 / (n-1); where n = 1, 2, ..., N, and N is the test particle number;

[0066] S13. Calculate the maximum-to-minimum radius ratio rn: rn = (Rn.m)max / (Rn.m)min; where n = 1, 2, ..., N, where N is the test particle number.

[0067] In the technical solutions of the embodiments of this application, particle size is analyzed based on the centroid combined with geometric and statistical parameters, while also characterizing the particle's morphological characteristics. Specifically, the particle size measurement result is based on the equivalent radius of the centroid, which directly reflects the overall particle size. Furthermore, the morphological characteristic results are based on centroid distance statistics, which can quantify particle irregularities such as roundness, aspect ratio, and roughness. This test method measures on a two-dimensional plane, and its measurement results are unaffected by the selected orientation. It can also provide accurate characterization of the particle size and morphology for particles with complex morphologies (such as dendritic or porous structures).

[0068] Furthermore, in some embodiments, in step S1, the ultrasonic dispersion treatment process includes the following steps: placing the particles to be tested in ethanol and oscillating in an ultrasonic oscillator for 15 to 25 minutes, wherein the volume of the ethanol is 5 to 10 times that of the particles to be tested.

[0069] Furthermore, in some embodiments, in step S1, the first resin curing process includes the following steps: adding epoxy resin to the particles to be tested mixed with graphite particles, shaking, and then curing at room temperature.

[0070] Furthermore, in some embodiments, in step S1, the particle size of the graphite particles is 0.1 to 0.5 times the minimum particle size of the particles to be tested, and the total volume of the graphite particles is 2 to 5 times the total volume of the particles to be tested.

[0071] In the technical solution of the embodiment of the present application, by mixing graphite of a specific particle size and the particles to be measured in a certain proportion, adhesion between the particles can be reduced and mismeasurement of the particle size can be prevented.

[0072] Furthermore, in some embodiments, in step S2, the sampling of the surface to be tested of the cutting block includes an upper bottom surface and a lower bottom surface of the cube solidified sample, an upper surface and a lower surface of any side surface of the cube solidified sample, an upper surface and a lower surface of the "cross" cutting surface, and any surface of the cutting surface of the horizontal midline cutting.

[0073] In the technical solution of the embodiment of the present application, the above-mentioned method of selecting the side surface can effectively avoid the problem of uneven particle distribution caused by the deposition of particles during the sample preparation process, thereby ensuring that the sampling is representative.

[0074] Furthermore, in some embodiments, in step S2, the second resin curing process includes the following steps: adding epoxy resin to the mold, and then curing it at 60-80°C.

[0075] Furthermore, in some embodiments, in step S3, the grinding and polishing is performed by grinding with 200-2000# SiC sandpaper and then polishing to a mirror surface with 0.05 μm aluminum oxide; and the thickness of the carbon spraying is 20-50 nm.

[0076] Furthermore, in some embodiments, in step S3, the number of particles exposed on the exposed surface of the test sample is not less than 1000.

[0077] In the technical solution of the embodiment of the present application, as many test particles as possible make the final analysis test results more accurate.

[0078] Furthermore, in some embodiments, in step S5, the threshold segmentation method is preferably an adaptive threshold method.

[0079] Furthermore, in some embodiments, in step S5, the morphological closing operation is to fill the holes of the particles in the test sample so that the particles form connected domains.

[0080] In the technical solution of the embodiment of the present application, the particles in the test sample are filled to ensure the connectivity and integrity of the particle area, making the detection and analysis more accurate and more precise. If this operation is not performed, anomalies will occur when the distal contact point is subsequently determined, resulting in errors in the centroid distance.

[0081] Furthermore, in some embodiments, in step S7, the total number of distal contact points is the total number of intersections between rays emitted at equal angles with the centroid of the particle as the origin and the distal edge; the equal angle is 5-20°.

[0082] In the technical solution of the embodiment of the present application, the intersection of the ray and the farthest edge is used as the far-end contact point, which can better reflect the overall structure of the particle.

[0083] Furthermore, in some embodiments, in step S11, when the particle size standard deviation SDn of the particles in the test sample is ≈ 0, the particles in the test sample are close to spherical; when the particle size standard deviation SDn of the particles in the test sample is much greater than 0, the shape of the particles in the test sample is highly irregular.

[0084] In the technical solution of the embodiment of the present application, the data can reflect whether the particles are regular and can also evaluate the roughness of the surface.

[0085] Furthermore, in some embodiments, in step S12, when the overall particle size standard deviation SD of the particles in the test sample is ≈ 0, the morphology of the particles in the test sample is uniform; when the overall particle size standard deviation SD of the particles in the test sample is much greater than 0, the shapes of the particles in the test sample are highly irregular.

[0086] In the technical solution of the embodiment of the present application, the data can reflect the overall uniformity of the particles in the sample.

[0087] Furthermore, in some embodiments, in step S13, when rn=1, the particles in the test sample are cubic or spherical.

[0088] In the technical solution of the embodiment of the present application, the data can characterize the flatness and anisotropy of the particles.

[0089] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0090] Example 1

[0091] This embodiment provides a method for measuring particle size and morphology, which specifically includes the following steps:

[0092] (1) Weigh 5 g of the overflow product from the mineral processing process, add 20 ml of ethanol, place it in an ultrasonic oscillator and vibrate for 20 minutes, dry it and place it in a mold, then add graphite particles with a particle size 0.5 times the minimum particle size of the overflow product from the mineral processing process and a volume twice the volume of the overflow product from the mineral processing process, then add 10 ml of epoxy resin, shake it, and cure it at room temperature to obtain a cube-shaped solidified sample with a side length of 2 cm.

[0093] (2) If Figure 1 As shown, the above-mentioned cube solidified sample is cut vertically along the midpoints of the four sides of the bottom square, and then cut along the horizontal midline to obtain 8 cut blocks of upper and lower layers. Then, the side surfaces are selected from these 8 cut blocks. The selected test surface is as follows Figure 2 As shown, the test surfaces c1 to c7 were placed into the mold with the surfaces facing downward, and 10 ml of epoxy resin was added to each of them. The samples were cured at 60° C. to obtain 7 vertical cylindrical cured samples.

[0094] (3) The bottoms of the seven vertical cylindrical solidified samples were ground with 200#, 800#, 1200#, and 500# SIC sandpaper respectively, and then polished to a mirror surface with 0.05μm alumina. The bottoms were then carbon-sprayed with a thickness of 20nm to obtain test samples.

[0095] (4) The resin glue background is removed by the adaptive threshold method, and the holes in the particles are filled, and edge processing is performed using pixels as the processing unit.

[0096] (5) Take a particle as an example and analyze its morphology. If n=1, then X1=1 / A* =256411.02, Y1=1 / A* =410.24, and the centroid coordinates of the particle are C1 (256411.02, 410.24).

[0097] (6) Calculate the centroid distance R1.m and the equivalent radius R1, R1.m=[(Xm-X1) 2 +(Ym-Y1) 2 ] 0.5 , R1=∑R1.m / m; where m=1, 2, 3, ..., is the total number of distal contact points of the particle; with the particle's centroid as the origin, rays are emitted at 10° intervals, and 36 intersection points of the rays with the particle's farthest edge are obtained, that is, m=36. The results of the calculated centroid distances and equivalent radii are shown in Table 1.

[0098] (7) The morphology of all particles on the exposed surface was analyzed, and the particle size distribution rate W was calculated. Then W = ΣKn.md, where d is the particle size classification corresponding to all particles on the exposed surface; Kn.m is the particle centroid distance distribution coefficient, Kn.m = (Rn.m / ΣRn.m)*Sn / ΣSn, Sn is the exposed area of ​​the particle; n = 1, 2, ..., M, M is the sample number in the particle size d; the exposed area Sn of all particles on the exposed surface was measured, and the particle centroid distance distribution coefficient Kn.m = (Rn.m / ΣRn.m)*Sn / ΣSn, where m = 36. The specific distribution coefficient and particle size distribution results are shown in Table 2 and Table 3, respectively.

[0099] Table 1 Measurement and analysis results of a particle in the mineral processing overflow sample

[0100]

[0101] Table 2 Distribution results of all particles

[0102]

[0103] Table 3 Particle size distribution of all particles

[0104]

[0105] Example 2

[0106] This embodiment provides a method for measuring particle size and morphology, which specifically includes the following steps:

[0107] The sample preparation, pre-test preparation and centroid distance test methods are the same as steps (1) to (6) in Example 1, wherein the particle to be tested is a calcined sample.

[0108] Analyze the particle size and morphology, calculate the average particle size R',

[0109] Rn'=∑Rn / n=(51.44+41.31+...+70.82) / 13632=43.22μm;

[0110] Calculate the standard deviation SDn of the particle size of a single particle to reflect the irregularity of the single particle.

[0111] SDn=[(Rn.m-∑Rn.m / m) 2 ] 0.5 / (m-1)=[(43.96-51.44) 2 +(50.37-51.44) 2 +(40.14-51.44) 2 +......+(38.45-51.44) 2 ] 0.5 / (36-1) = 0.93;

[0112] Calculate the overall particle size standard deviation SD of the particles to reflect the overall particle irregularity of the entire sample and evaluate the surface roughness;

[0113] SD=[∑(Rn-R') 2 ] 0.5 / (n-1)=[(51.44-43.22) 2 +(41.34-43.22) 2 (17.28-43.22) 2 +......+(70.82-43.22) 2 ] 0.5 / (13632-1) = 0.82;

[0114] Calculate the maximum / minimum radius ratio rn, which describes the flatness or anisotropy of the particles;

[0115] The analysis and test results are shown in Table 4.

[0116] Table 4 Measurement and analysis results of calcined sample particles

[0117]

[0118] From Table 4, it can be concluded that the D50 of the calcined sample particles is 32 μm, the aspect ratio r is 2.33, SDn is 0.82 (rough surface), SD > 0, SDn > 0, so the particle morphology is irregular and long-grained. The morphological characteristics of the calcined sample particles observed under a microscope are basically consistent with the data analysis results obtained in this embodiment. This result can further guide the optimization of the sintering process.

[0119] The pictures observed under stereo microscope and automatic mineralogy instrument are as follows Figure 3 As shown, it can be seen that the particles observed under stereomicroscope are porous, while the particles under automineralogy are connected domains.

[0120] In summary, the present application provides a method for measuring particle size and morphology. A method for measuring particle size on a two-dimensional plane is designed, which can effectively avoid direction dependence and embed morphological information in particle size measurement, and is suitable for the analysis of complex particle systems (such as geological sediments, industrial powders or biological particles). Based on the particle centroid combined with geometric and statistical parameters, the particle size is analyzed, and the morphological characteristics of the particles are analyzed and characterized. The specific particle size measurement result is an equivalent radius result based on the centroid, which can directly reflect the overall size of the particle. Furthermore, the morphological characteristic result is based on centroid distance statistics, which can quantify the irregularity of the particle, such as roundness, aspect ratio, roughness, etc.; this test method measures on a two-dimensional plane, and its measurement results are not affected by the selected direction, and can provide accurate particle size and morphology characterization for particles with complex morphologies (such as dendritic or porous structures), providing a reliable test method for the analysis of complex particle systems (such as geological sediments, industrial powders or biological particles).

[0121] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other methods constructed by applying various modifications that can be imagined by those skilled in the art to the embodiments and combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for measuring particle size and morphology, characterized in that: The following steps are involved: S1. Take the particles to be tested and perform ultrasonic dispersion treatment, dry them, mix them with graphite particles, and then perform the first resin curing to obtain a cube-cured sample; S2. The cube-shaped solidified sample was cut vertically along the midpoints of the four sides of the bottom square, and then cut along the horizontal midline to obtain upper and lower layers of cut blocks. The cut blocks were then placed with the test surface facing down and the resin was cured for the second time to obtain multiple vertical cylindrical solidified samples. S3. The bottom surfaces of the plurality of vertical cylindrical solidified samples were ground and polished, and carbon sprayed to obtain test samples; S4. performing automatic mineralogical analysis on the test sample, and extracting particles from the test sample by a threshold segmentation method; S5. Performing morphological closing operation on the holes of the particles in the test sample and processing the edges of the particles in the test sample in pixel units; S6. Measure the total area of ​​the particle pixels of the particles in the test sample as A, and the micro-unit area of ​​the particle pixels as dA; and denote the centroid position coordinates of the particles in the test sample as Cn(Xn, Yn); where n = 1, 2, ..., N, where N is the test particle number; Then Xn = 1 / A * , Yn = 1 / A * ; S7. Calculate the centroid distance Rn.m of the particles in the test sample, Then Rn.m = [(Xm - Xn) 2 + (Ym - Yn) 2 0.5 ;​ Where m = 1, 2, 3, ..., is the total number of distal contact points of the particles in the measured sample; S8. Calculate the equivalent radius Rn of the particles in the test sample, then Rn=∑Rnm / m; S9. Calculate the particle size distribution rate W of the particles in the test sample, where W = ΣKn.md; where d is the particle size fraction corresponding to the particles in the test sample; where Kn.m is the centroid distance distribution coefficient of the particles in the test sample, Kn.m = (Rn.m / ΣRn.m)*Sn / ΣSn, where Sn is the exposed area of ​​the particles; and n = 1, 2, ..., M, where M is the sample number in particle fraction d; S10. Calculate the average particle size Rn' of the particles in the test sample, where Rn'=∑Rn / n; wherein n=1, 2, ..., N, where N is the test particle number; S11. Calculate the standard deviation SDn of the particle size in the test sample, then SDn=[(Rn.m-∑Rn.m / m) 2 ] 0.5 / (m-1); where n=1, 2, ..., N, and N is the test particle number; S12. Calculate the overall particle size standard deviation SD of the particles in the test sample, then SD=[∑(Rn-Rn') 2 ] 0.5 / (n-1); where n = 1, 2, ..., N, and N is the test particle number; S13. Calculate the maximum-to-minimum radius ratio rn: rn = (Rn.m)max / (Rn.m)min; where n = 1, 2, ..., N, where N is the test particle number.

2. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S1, the particle size of the graphite particles is 0.1 to 0.5 times the minimum particle size of the particles to be tested, and the total volume of the graphite particles is 2 to 5 times the total volume of the particles to be tested.

3. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S2, the sampling of the surface to be tested of the cutting block includes an upper bottom surface and a lower bottom surface of the cube solidified sample, an upper surface and a lower surface of any side surface of the cube solidified sample, an upper surface and a lower surface of the "cross" cutting surface, and any surface of the cutting surface of the horizontal midline cutting.

4. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S3, the number of particles exposed on the exposed surface of the test sample is not less than 1000.

5. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S5, the morphological closing operation is to fill the holes of the particles in the test sample so that the particles form connected domains.

6. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S7, the total number of distal contact points is the total number of intersections between rays emitted at equal angles from the particle's centroid and the distal edge.

7. The method for measuring particle size and morphology according to claim 6, characterized in that: The equal angle is 5 to 20 degrees.

8. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S11, when the particle size standard deviation SDn of the particles in the test sample is ≈0, the particles in the test sample are close to spherical; when the particle size standard deviation SDn of the particles in the test sample is much greater than 0, the particles in the test sample are highly irregular in shape.

9. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S12, when the overall particle size standard deviation SD of the particles in the test sample is ≈ 0, the morphology of the particles in the test sample is uniform; when the overall particle size standard deviation SD of the particles in the test sample is much greater than 0, the shapes of the particles in the test sample are highly irregular.

10. The method for measuring particle size and morphology according to claim 1, characterized in that: In step S13, when rn=1, the particles in the test sample are cubic or spherical.

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