Method for determining sampling amount of particle size analysis

Abstract

The invention discloses a method for determining the sampling amount of particle size analysis, and belongs to the technical field of particle size analysis of particle materials, and the method comprises the following steps: selecting a reference substance with a regular shape and stable properties, and determining the optimal sampling amount of the reference substance under a preset shading rate condition, the characteristic radius based on the particle size distribution and the true density of the reference substance; measuring the characteristic radius, the density and the porosity of the to-be-measured substance; and based on an equivalent scattering area principle, calculating the sampling amount of the to-be-measured substance by utilizing the optimal sampling amount, the characteristic radius and the real density of the reference substance and the characteristic radius, the density and the porosity of the to-be-measured substance. A regular and stable reference substance is selected, a reference standard under an ideal shading rate is determined, and the sampling amount is calculated according to an equivalent scattering area principle, a correlation standard and to-be-measured parameters by combining the characteristic radius, the density and the porosity of a to-be-measured substance, so that the conversion of the sampling amount from experience to scientific calculation is realized; and the calculation mode can also be suitable for complicated samples with irregular shapes and porous interiors.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of particle size analysis of granular materials, and particularly relates to a method for determining a sampling amount for particle size analysis. BACKGROUND

[0002] In the actual operation of laser particle size analysis, the selection of the sampling amount is a key factor for determining the accuracy and repeatability of the measurement results. After the sample is put into the dispersion medium, the concentration of the suspension in front of the detection window needs to be ensured to be within the ideal range recommended by the instrument. If the light blocking rate is too low, it means that the number of particles is too small, and the scattering signal is weak, which will lead to poor data signal-to-noise ratio and low repeatability; if the light blocking rate is too high, it means that the particle concentration is too large, which will lead to multiple scattering effects, i.e., the light is continuously scattered by multiple particles, so that the measurement results are seriously deviated to the direction of coarse particles, causing significant deviation.

[0003] At present, the determination of the sampling amount generally adopts an empirical method, which cannot quantify the influence of the physical property parameters of the sample to be tested, so that when facing new and complex samples, the reference method is completely invalid, and can only return to the low-efficiency light blocking rate guidance method. SUMMARY

[0004] In view of the technical problems in the background art, the present application provides a method for determining a sampling amount for particle size analysis, comprising: selecting a reference substance with regular shape and stable properties to determine an optimal sampling amount of the reference substance under a predetermined light blocking rate condition, a characteristic radius based on a particle size distribution of the reference substance, and a true density of the reference substance; measuring a characteristic radius, a density, and a porosity of a substance to be tested; based on the principle of equivalent scattering area, using the optimal sampling amount, the characteristic radius, and the true density of the reference substance, and the characteristic radius, the density, and the porosity of the substance to be tested, to calculate the sampling amount of the substance to be tested.

[0005] In some embodiments, the selecting a reference substance with regular shape and stable properties to determine an optimal sampling amount of the reference substance under a predetermined light blocking rate condition, a characteristic radius based on a particle size distribution of the reference substance, and a true density of the reference substance comprises: selecting a reference substance with regular shape and stable properties; the reference substance comprises any one of a standard latex microsphere, a diamond spherical particle, a quartz spherical particle, or a stainless steel spherical particle; measuring a particle size distribution of the reference substance using a laser particle size analyzer, and calculating a characteristic radius of the reference substance based on the particle size distribution; under an ideal light blocking rate condition, determining an optimal sampling amount of the reference substance according to the characteristic radius of the reference substance, and measuring a true density of the reference substance.

[0006] In some embodiments, in the calculation of the characteristic radius of the reference material based on the particle size distribution, the steps include: extracting at least three characteristic particle sizes from the particle size distribution of the reference material; the characteristic particle sizes are , , and , n is an integer between 10 and 30; calculating the characteristic radius of the reference material based on the characteristic particle sizes.

[0007] In some embodiments, in the step of extracting at least three characteristic particle sizes from the particle size distribution of the reference material, the value of n is preferably 20, and the corresponding characteristic particle sizes are , , and .

[0008] In some embodiments, the steps of measuring the characteristic radius, density and porosity of the test material include: performing preliminary particle size measurement on the test material, and calculating the characteristic radius of the test material based on the measured particle size distribution; measuring the density of the test material; measuring the porosity of the test material by mercury porosimeter, nitrogen adsorption instrument or density method.

[0009] In some embodiments, the steps of performing preliminary particle size measurement on the test material and calculating the characteristic radius of the test material based on the measured particle size distribution include: after the preliminary particle size measurement of the test material, extracting the median particle size of the particle size distribution, and calculating the characteristic radius of the test material; the characteristic radius of the test material is .

[0010] In some embodiments, the steps of calculating the sampling amount of the test material based on the equivalent scattering area principle and using the preferred sampling amount, characteristic radius, true density of the reference material and the characteristic radius, density and porosity of the test material include: calculating the total scattering area of the reference material based on the preferred sampling amount , characteristic radius and true density of the reference material; calculating the total scattering area of the test material based on the density , characteristic radius and porosity of the test material. make = The sample amount of the substance to be tested is obtained.

[0011] In some embodiments, determining the preferred sampling amount of the reference material under ideal shading conditions and measuring the true density of the reference material includes: The ideal shading rate is 10%-20%; Determine the optimal sampling amount for the reference material; Use a specific gravity bottle or helium hydrometer to measure the true density of the reference material.

[0012] In some embodiments, determining the preferred sample size of the reference material includes: Weigh a small amount of the pretreated reference material and put it into the dispersion medium of the laser particle size analyzer; Start the laser particle size analyzer, monitor the real-time shading rate value displayed by the instrument, and adjust the sample amount to keep the shading rate within the ideal range of 10%-20%. Perform multiple particle size distribution measurements and calculate the relative deviation of the particle size distribution characteristic values. The sample amount of the reference material when the deviation value is less than the preset value is taken as the preferred sample amount.

[0013] In some embodiments, measuring the density of the substance to be tested includes: Use a specific gravity bottle or a helium hydrometer for measurement.

[0014] This application provides a method for determining the sampling amount for particle size analysis, including: Select a reference material with regular shape and stable properties, and determine the optimal sampling amount, characteristic radius based on its particle size distribution, and true density of the reference material under a predetermined shading rate. Measure the characteristic radius, density, and porosity of the substance to be tested; Based on the principle of equivalent scattering area, the sample quantity of the test substance is calculated by using the preferred sample quantity, characteristic radius, and true density of the reference material and the characteristic radius, density, and porosity of the test substance.

[0015] By selecting a regular and stable reference material, the sampling amount, characteristic radius, and true density under its ideal shading rate are determined to obtain a reference standard. Combined with the characteristic radius, density, and porosity of the material to be tested, the sampling amount is calculated by correlating the reference and the parameters to be tested according to the principle of equivalent scattering area. This realizes the transformation of the sampling amount from experience to scientific calculation, and makes this calculation method applicable to complex samples with irregular shapes and porous interiors. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0017] Figure 1 This is a schematic diagram of the overall process of a method for determining the sampling amount for particle size analysis provided in an embodiment of this application; Figure 2 This is a detailed flowchart of step S10 in a method for determining the sampling amount for particle size analysis provided in an embodiment of this application. Figure 3 This is a flowchart illustrating a further refinement of step S10 in a method for determining the sampling amount for particle size analysis provided in an embodiment of this application. Figure 4 This is a detailed flowchart of step S20 in a method for determining the sampling amount for particle size analysis provided in an embodiment of this application. Figure 5 This is a flowchart illustrating a further refinement of step S20 in a method for determining the sampling amount for particle size analysis provided in an embodiment of this application. Figure 6 This is a detailed flowchart of step S30 in a method for determining the sampling amount for particle size analysis provided in an embodiment of this application. Figure 7 This is a schematic diagram of the overall process after refinement in step S13 of step S10 of a method for determining the sampling amount for particle size analysis provided in an embodiment of this application. Detailed Implementation

[0018] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0024] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] In some implementations, refer to Figure 1 A method for determining the sampling amount for particle size analysis, comprising: S10. Select a reference material with regular shape and stable properties, and determine the optimal sampling amount, characteristic radius based on its particle size distribution, and true density of the reference material under a predetermined shading rate. Specifically, the purpose of this step is to screen a reference material with uniform physical properties that can be accurately quantified, and to obtain three sets of key calibration parameters through experiments and calculations: the optimal sampling amount that can produce an ideal shading rate, the characteristic radius that reflects the particle size distribution, and the true density that eliminates pore interference. This establishes a unified and reliable reference standard for subsequent calculations of the sampling amount of the substance to be tested, thereby solving the problem of sampling amount estimation deviation caused by the lack of a unified calibration standard in traditional methods, and ensuring that subsequent calculations are based on scientifically comparable physical parameters, rather than empirical judgments.

[0028] For example, microspheres with high particle size uniformity, good thermal stability, and resistance to oxidation can be selected, such as monodisperse zirconia spherical particles or high-purity monocrystalline silicon microspheres. Zirconia particles are suitable for particle size analysis calibration in high-temperature environments, while monocrystalline silicon microspheres can have their crystal structure accurately determined by XRD, further improving the accuracy of density measurement.

[0029] For example, using a gradient sampling method combined with shading rate fitting, 5 to 8 portions of reference material are taken at a gradient of 0.1g, and the shading rate is measured for each portion. A sampling mass-shading rate curve is plotted, and the sampling mass corresponding to the midpoint of the predetermined shading rate interval in the curve is taken as the optimal sampling amount. Alternatively, the instrument's automatic calibration function can be used, and the density and particle size range of the reference material can be input. The optimal sampling amount can be confirmed through one manual verification. .

[0030] For example, calculating the characteristic radius of a reference material. ,Pick Based on the base radius, according to Narrow-distribution reference material correction is performed, where CV is the particle size distribution variation coefficient, which is obtained by linear fitting of experimental data.

[0031] For example, measuring the true density of a reference material. One method involves placing the reference material in a vacuum container to remove surface-adsorbed gases, then measuring the volume using the water displacement method and calculating the density based on the mass. This method is suitable for reference materials that are non-porous and insoluble in water. Alternatively, the XRD method can be used to calculate the theoretical true density using crystal structure parameters, molar mass, and unit cell volume. This method is suitable for reference materials with well-defined crystal structures, such as the single-crystal silicon microspheres mentioned above.

[0032] S20. Measure the characteristic radius, density, and porosity of the test material. Specifically, for non-spherical, porous, and complex-shaped test materials, measure and obtain the characteristic radius reflecting particle size characteristics, the density reflecting the material's compactness, and the porosity quantifying the proportion of internal pores, providing comparable parameters with reference materials for subsequent equivalent calculations. For example, measure the characteristic radius of the test material. Measure the substance to be tested , , and ,according to =0.5 ( + + + The calculation of ) / 4 is applicable to porous samples with complex distributions.

[0033] For example, measuring the density of the substance to be tested. The density was measured using the same method as in S10 for measuring the true density of the reference material.

[0034] For example, the porosity of the substance to be tested is measured using the liquid nitrogen adsorption-desorption method. The specific surface area and pore volume are calculated through adsorption isotherms, and the porosity is derived. .

[0035] S30. Based on the principle of equivalent scattering area, the sample quantity of the test substance is calculated using the preferred sampling amount, characteristic radius, and true density of the reference material and the characteristic radius, density, and porosity of the test substance. Specifically, based on the equivalence of the scattering areas of the reference material and the test substance, the reference parameters obtained in step S10, i.e., the preferred sampling amount, are used. Characteristic radius True density The parameters of the substance to be tested obtained in step S20, namely the density of the substance to be tested. Characteristic radius Porosity By substituting into a preset mathematical model, the sample quantity of the substance to be tested can be directly obtained through quantitative calculation, thereby realizing the transformation of the sample quantity from empirical trial to scientific calculation. This ensures that the intensity of the scattering signal generated by the substance to be tested in the laser particle size analyzer is consistent with that of the reference substance, and the shading rate is stable within the ideal range, while reducing sample waste and debugging time.

[0036] For example, for highly irregular analytes such as needle-shaped or sheet-shaped substances, a shape correction coefficient k is introduced, where k = specific surface area of ​​the analyte / specific surface area of ​​spherical particles of the same volume. The correction formula is obtained by measuring with a nitrogen adsorption analyzer. Through k and Eliminate the differences in specific surface area and volume between needle-shaped, flaky, and spherical particles.

[0037] This application provides a method for determining the sampling amount for particle size analysis, including: S10. Select a reference material with regular shape and stable properties, and determine the preferred sampling amount, characteristic radius based on its particle size distribution, and true density of the reference material under a predetermined shading rate. S20. Measure the characteristic radius, density and porosity of the substance to be tested; S30. Based on the principle of equivalent scattering area, the sample quantity of the test substance is calculated by using the preferred sampling amount, characteristic radius, and true density of the reference material and the characteristic radius, density, and porosity of the test substance.

[0038] By selecting a regular and stable reference material, the sampling amount, characteristic radius, and true density under its ideal shading rate are determined to obtain a reference standard. Combined with the characteristic radius, density, and porosity of the material to be tested, the sampling amount is calculated by correlating the reference and the parameters to be tested according to the principle of equivalent scattering area. This realizes the transformation of the sampling amount from experience to scientific calculation, and makes this calculation method applicable to complex samples with irregular shapes and porous interiors.

[0039] In some implementations, refer to Figure 2 S10. Select a reference material with regular shape and stable properties, and determine the optimal sampling amount, characteristic radius based on its particle size distribution, and true density of the reference material under a predetermined shading rate condition, including: S11. Select a reference material with regular shape and stable properties. The reference material includes any one of the following: standard latex microspheres, diamond spherical particles, quartz spherical particles, or stainless steel spherical particles. Specifically, the key reason for the failure of the standard sample reference method in the prior art is the huge difference between the standard sample and the sample to be tested in terms of shape, density, and porosity, and the standard sample itself may have irregular shape and unstable properties. Therefore, this step selects a spherical material with regular shape, which can eliminate the interference of particle shape differences on the scattering area and ensure the repeatability of the reference parameters.

[0040] S12. Measure the particle size distribution of the reference material using a laser particle size analyzer, and calculate the characteristic radius of the reference material based on the particle size distribution. For example, using a laser particle size analyzer, under the instrument's recommended ideal shading rate of 10%-20%, measure the particle size distribution of the reference material, obtain multiple characteristic values, and take the average characteristic radius. Thus ensuring Its reference value.

[0041] S13. Under ideal shading conditions, determine the optimal sampling amount of the reference material based on its characteristic radius, and measure the true density of the reference material. The optimal sampling amount... The measurement conditions must be verified to meet the optimal requirements for laser particle size analysis, thereby ensuring the corresponding scattering area. It can reflect the total scattering contribution under optimal measurement conditions. As a calibration basis, it ensures that subsequent analytes pass through. Calculated sample size This also achieves the same ideal measurement conditions, thus avoiding the problem of repeated adjustments in traditional shading rate guidance methods. Simultaneously, the true density... It is the density of the pure solid phase of the reference material, for a non-porous reference material. It is a constant value, unaffected by porosity. The number of particles in the reference material, however, is directly related to it and can only be determined through accurate measurement. Only by deriving the formula can the number of particles be obtained, and then the total scattering area can be calculated. .

[0042] In some implementations, refer to Figure 3 The characteristic radius of the reference material calculated based on particle size distribution in S12 includes: S121. Extract at least three characteristic particle sizes from the particle size distribution of the reference material; the characteristic particle sizes are... , , and n is an integer between 10 and 30; The characteristic radius of the reference material is obtained by calculating the characteristic particle size.

[0043] Specifically, This represents the particle diameter corresponding to a cumulative volume fraction of n%. Similarly, It is the diameter when the cumulative volume fraction is 20% + n%. It is the diameter when the cumulative percentage is 80%-n%. It is the diameter when the cumulative value is 100%-n%. When n is between 10 and 30, the particle size can uniformly cover the entire range of particle size distribution, avoiding deviation in a single range.

[0044] For example, if n=10: the combination is (Fine end, more front end) (Middle and fine ends) (Medium-thick end) (The thicker end is more advanced than the rear end); If n=30: the combination is (Middle and fine ends) (Mid-range) (Medium-thick end); Regardless of the value of n within this range, this set of particle sizes always covers the core region, ensuring that the particle size distribution characteristics can be fully captured, rather than just reflecting the particle size at a single location.

[0045] Characteristic radius Calculated using the average radius method, it can be expressed as: If the value of n causes two particle sizes to overlap, the denominator is adjusted according to the actual number of effective particle sizes. For example, when there are 3 effective particle sizes, the denominator is 3 to ensure that the average logic remains unchanged.

[0046] This allows for the averaging of multiple feature particle sizes covering the entire range to a feature radius that represents the entire particle size distribution, has small error, and is repeatable. This correlates particle size with scattering area, providing parameters for sample quantity calculation.

[0047] In some embodiments, in S121, when extracting at least three characteristic particle sizes from the particle size distribution of the reference material, the value of n is preferably 20, and the corresponding characteristic particle sizes are... , , and .

[0048] Specifically, the cumulative volume fractions corresponding to the four particle sizes are 20%, 40%, 60%, and 80%, respectively, with adjacent particle sizes spaced 20% apart, exhibiting an equidistant distribution. This uniform spacing ensures that the three core regions—fine, medium, and coarse—are given equal importance, preventing the characteristic radius from being skewed due to the absence of particle sizes in any particular region, thus guaranteeing the characteristic radius. Representativeness.

[0049] In some implementations, refer to Figure 4 S20. Measuring the characteristic radius, density, and porosity of the substance to be tested includes: S21. Perform preliminary particle size measurement on the substance to be tested, and calculate the characteristic radius of the substance to be tested based on the particle size distribution obtained from the measurement. S22. Measure the density of the substance to be tested; S23. Measure the porosity of the substance to be tested using a mercury porosimeter, nitrogen adsorption analyzer, or density method.

[0050] In some implementations, refer to Figure 5 A preliminary particle size measurement is performed on the substance to be tested, and the characteristic radius of the substance to be tested is calculated based on the particle size distribution obtained from the measurement, including: S211. After preliminary particle size measurement of the substance to be tested, extract the median particle size of its particle size distribution. Calculate the characteristic radius of the substance to be tested. Characteristic radius of the substance to be tested =0.5× Specifically, the reference material is used... , , and The multi-value averaging method is used because it's a calibration scale; it needs to compensate for errors by covering the entire distribution with multiple values ​​to ensure accuracy. Reliable. The test substance uses... Single-value calculation is used because it involves the object being measured, requiring both convenience and sample-saving considerations, and its complex physical properties can be analyzed through subsequent porosity calculations. correction, It already provides sufficiently accurate particle size characteristics, eliminating the need for multi-value averaging. Thus, on the one hand, the accuracy of the calibration basis is ensured through multi-value averaging of the reference material, and on the other hand, the accuracy of the analyte is guaranteed by the multi-value averaging of the reference material. Single-value calculations improve convenience.

[0051] In some implementations, refer to Figure 6 S30. Based on the principle of equivalent scattering area, using the preferred sampling amount, characteristic radius, and true density of the reference material and the characteristic radius, density, and porosity of the analyte, the sampling amount of the analyte is calculated, including: S31. Optimize sampling amount based on reference material Characteristic radius True density The total scattering area of ​​the reference material was calculated. ; S32, Based on the density of the substance to be measured Characteristic radius Porosity The total scattering area of ​​the substance to be tested was calculated. ; S33, Order = The sample amount of the substance to be tested is obtained.

[0052] For example, the known parameters of the reference material, i.e., the preferred sampling amount. Characteristic radius True density Substitute into the derived formula to calculate the total scattering area The calculation formula is: Through formula derivation, a clear mathematical relationship is established between the sampling amount of the reference material, its physical properties, and its scattering area, thus providing a reusable calibration model for subsequent calculations.

[0053] For example, the density of the substance to be measured is... Characteristic radius Porosity With unknown sample size Substituting into the derived formula, the total scattering area of ​​the substance to be measured is established. The expression: By adjusting the effective solid volume and effective surface area, the sampling amount can be reduced. Calculation distortion.

[0054] For example, combined and The formula, through the principle of equivalent scattering area, makes = Solve for the sample amount of the substance to be tested. ,Right now: After sorting, we get: Thus, the sampling amount is obtained. .

[0055] In some implementations, refer to Figure 7 S13. Under ideal shading conditions, determine the optimal sampling amount of the reference material and measure the true density of the reference material, including: S131. The ideal shading rate is 10%-20%. Specifically, the ideal shading rate range for laser particle size analysis is 10%-20%. When determining the optimal sampling amount of the reference material, the core criterion is that the shading rate is stably within this range.

[0056] S132. Determine the preferred sampling amount of the reference material; for example, this includes: In some embodiments, S132, determining the preferred sample size of the reference material includes: S1321. Weigh a small amount of the pretreated reference material and put it into the dispersion medium of the laser particle size analyzer. For example, the reference material is dried at 105°C for 2-4 hours and then cooled to room temperature; Weigh 0.1~1g of sample using an electronic balance, with the minimum requirement being that the instrument can recognize the scattering signal; Slowly add the sample into the dispersion cell of the laser particle size analyzer.

[0057] S1322. Start the laser particle size analyzer, monitor the real-time shading rate value displayed by the instrument, and adjust the sample amount to keep the shading rate in the ideal range of 10%-20%. For example, start the laser particle size analyzer, and after the preheating is complete, turn on the "real-time shading rate monitoring" function; Observe the shading rate value displayed by the instrument. If the shading rate is <10%, add a small amount of the pretreated reference material with a spoon or dropper. Stir for 30 seconds after each addition and then monitor again until the shading rate reaches 10%-20%. If the occlusion rate is >20%, use a pipette to aspirate a small amount of the sample suspension (or add a small amount of dispersion medium to dilute it), stir well, and then monitor again until the occlusion rate drops back to 10%-20%. Preferably, the shading rate should be adjusted to the middle value of the range, such as 15%, to avoid fluctuations in subsequent measurements caused by being close to the range boundary.

[0058] S1323. Perform multiple particle size distribution measurements and calculate the relative deviation of the particle size distribution characteristic values. The sample amount of the reference material when the deviation value is less than the preset value is taken as the preferred sample amount.

[0059] For example, under the condition that the current shading rate is stable, particle size distribution measurements are performed three or more times consecutively; Extract the particle size distribution characteristic values ​​for each measurement and calculate the relative deviation of the same characteristic value; If the relative deviations of all characteristic values ​​are less than the preset values ​​(the industry standard preset value is ≤1%, or adjusted to ≤0.5% based on instrument accuracy), then the current sample quality is the optimal sampling amount. .

[0060] S133. Measure the true density of the reference material using a specific gravity bottle or a helium hydrometer.

[0061] In some implementations, measuring the density of the substance to be tested includes: Use a specific gravity bottle or a helium hydrometer for measurement.

[0062] In some implementations, the specific calculation process of this application is provided: Step 1: Determine the optimal sampling amount and characteristic radius of the reference material.

[0063] Reference material selected: stainless steel microspheres; Particle size of reference material: The particle size distribution was measured using a laser particle size analyzer under optimal 10% shading conditions. Characteristic values ​​of the particle size distribution were measured. , , and n=20. The corresponding micrometers are 18.50μm, 19.82μm, 21.22μm, and 22.25μm.

[0064] Average radius =0.5 ( + + + ) / 4=0.5 (18.50+19.82+21.22+22.25μm) / 4=10.22μm.

[0065] Record the optimal sampling quality of the reference material , =0.52g (experimentally verified, the shading rate at this mass is 15%). This sample mass, which has been verified to produce the ideal shading rate, serves as the basis for the calibration of the entire method.

[0066] Step two: Use a specific gravity bottle to measure the true density of the reference substance. , =7.8g / cm³; Step 3: Calculate the particle size measurement area of ​​the spherical reference material. ,but =3 / 4 / ( ); Step 4: Determine the characteristic radius of the substance to be tested. ; The median particle size was initially measured using a particle size analyzer. =50μm; Calculate the characteristic radius of the substance to be tested :but =0.5 =25μm.

[0067] Step 5: Measure its density, similar to step 2, which measures the density of the substance being tested. , =3.2 g / cm³, the porosity of the substance being tested was measured. , =0.85, using a nitrogen adsorption instrument; Step 6: Calculate the particle size measurement area of ​​the sample. : Step 7: Calculate the sample size of the substance to be tested.

[0068] =1.5 0.52 3.2 25 0.53 / (7.8) 10.22) = 0.41g; According to calculations, the optimal sample size for measuring this batch of active alumina catalyst is approximately 0.41g.

[0069] During formal measurements, its shading rate was close to 15% of the reference material, which is within the ideal range. See Table 1 below for details.

[0070] Table 1 The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

[0071] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for determining the sampling amount for particle size analysis, characterized in that, include: Select a reference material with regular shape and stable properties, and determine the preferred sampling amount, characteristic radius based on its particle size distribution, and true density of the reference material under a predetermined shading rate condition. Measure the characteristic radius, density, and porosity of the substance to be tested; Based on the principle of equivalent scattering area, the sample quantity of the test substance is calculated by using the preferred sample quantity, characteristic radius, and true density of the reference material and the characteristic radius, density, and porosity of the test substance.

2. The method for determining the sampling amount for particle size analysis according to claim 1, characterized in that, The selection of a reference material with regular shape and stable properties, and the determination of the preferred sampling amount, characteristic radius based on its particle size distribution, and true density of the reference material under a predetermined shading rate condition, include: Select a reference material with a regular shape and stable properties; the reference material includes any one of standard latex microspheres, diamond spherical particles, quartz spherical particles, or stainless steel spherical particles. The particle size distribution of a reference material is measured using a laser particle size analyzer, and the characteristic radius of the reference material is calculated based on the particle size distribution. Under ideal shading conditions, the preferred sampling amount of the reference material is determined based on the characteristic radius of the reference material, and the true density of the reference material is measured.

3. The method for determining the sampling amount for particle size analysis according to claim 2, characterized in that, The characteristic radius of the reference material calculated based on the particle size distribution includes: From the particle size distribution of the reference material, at least three characteristic particle sizes are extracted; the characteristic particle sizes are... , , and n is an integer between 10 and 30; The characteristic radius of the reference material is calculated using the characteristic particle size.

4. The method for determining the sampling amount for particle size analysis according to claim 3, characterized in that, In the extraction of at least three characteristic particle sizes from the particle size distribution of the reference material, the value of n is preferably 20, and the corresponding characteristic particle sizes are: , , and .

5. The method for determining the sampling amount for particle size analysis according to claim 1, characterized in that, The measurement of the characteristic radius, density, and porosity of the substance to be tested includes: A preliminary particle size measurement is performed on the substance to be tested, and the characteristic radius of the substance to be tested is calculated based on the particle size distribution obtained from the measurement. Measure the density of the substance to be tested; The porosity of the substance to be tested is measured by mercury porosimetry, nitrogen adsorption, or density method.

6. The method for determining the sampling amount for particle size analysis according to claim 5, characterized in that, The preliminary particle size measurement of the substance to be tested, and the calculation of the characteristic radius of the substance to be tested based on the measured particle size distribution, include: After preliminary particle size measurement of the sample, the median particle size of its particle size distribution is extracted. Calculate the characteristic radius of the substance to be tested. The characteristic radius of the substance to be tested =0.5× .

7. The method for determining the sampling amount for particle size analysis according to claim 1, characterized in that, Based on the principle of equivalent scattering area, the sample quantity of the test substance is calculated by using the preferred sample quantity, characteristic radius, and true density of the reference material and the characteristic radius, density, and porosity of the test substance. Optimal sampling amount based on reference material Characteristic radius True density The total scattering area of ​​the reference material was calculated. ; Based on the density of the substance to be measured Characteristic radius Porosity The total scattering area of ​​the substance to be tested was calculated. ; make = The sample amount of the substance to be tested is obtained.

8. The method for determining the sampling amount for particle size analysis according to claim 2, characterized in that, Determining the optimal sampling amount of the reference material under ideal shading conditions and measuring the true density of the reference material includes: The ideal shading rate is 10%-20%; Determine the optimal sampling amount for the reference material; Use a specific gravity bottle or helium hydrometer to measure the true density of the reference material.

9. The method for determining the sampling amount for particle size analysis according to claim 8, characterized in that, The determination of the preferred sampling amount of the reference material includes: Weigh a small amount of the pretreated reference material and put it into the dispersion medium of the laser particle size analyzer; Start the laser particle size analyzer, monitor the real-time shading rate value displayed by the instrument, and adjust the sample amount to keep the shading rate within the ideal range of 10%-20%. Perform multiple particle size distribution measurements and calculate the relative deviation of the particle size distribution characteristic values. The sample amount of the reference material when the deviation value is less than the preset value is taken as the preferred sample amount.

10. The method for determining the sampling amount for particle size analysis according to claim 5, characterized in that, The measurement of the density of the substance to be tested includes: Use a specific gravity bottle or a helium hydrometer for measurement.

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