A fly ash particle size analysis method and system

Abstract

The present invention provides a method and system for analyzing the particle size of fly ash. By optimizing the drying and dispersion treatment of samples and combining laser particle size analysis and image analysis techniques, the particle size distribution of fly ash samples can be accurately measured. The method includes drying the samples to ensure that the water content is less than 0.5%; using ultrasonic or air flow dispersion techniques to evenly disperse the particles; measuring the particle size with a laser particle size analyzer to generate a cumulative distribution curve; calculating the median particle size and specific surface area through the cumulative distribution curve. The system of the present invention has an automated operation function and can automatically complete sample processing, particle size measurement, data analysis, and result output. This method improves the accuracy of measurement and the precision of data processing, is suitable for the efficient analysis of a large number of samples, and has broad industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering, and specifically to a method and system for analyzing the particle size of fly ash. Background Art

[0002] Fly ash is a fine-grained waste discharged from coal-fired power plants, mainly composed of mineral residues that are not completely burned during the coal combustion process. Due to its fine particles and rich chemical composition, fly ash has broad application prospects in fields such as building materials, road paving, and environmental protection projects. However, the physical and chemical properties of fly ash, such as particle size distribution and specific surface area, directly affect its application effects in these fields. Therefore, accurately measuring and analyzing the particle size distribution and specific surface area of fly ash is of great significance for improving the utilization efficiency of fly ash.

[0003] Currently, the methods for analyzing the particle size of fly ash mainly include screening method, sedimentation method, laser particle size analysis method, and image analysis method, etc. Among them, the screening method is widely used for the particle size analysis of coarse-grained powders due to its simple operation. However, for fine-grained substances like fly ash, the screening method has low precision and is difficult to accurately measure the particle size distribution. The sedimentation method estimates the particle size by the sedimentation velocity of particles in a liquid. Although it can be applied to the analysis of finer particles, it is limited by the operating environment and the influence of the liquid medium, and the stability and reproducibility of the test results are poor. The laser particle size analysis method measures the particle size distribution through the principle of laser scattering, which has high precision and repeatability and has become the mainstream method for fly ash particle size analysis. However, this method relies on expensive equipment, has high requirements for sample pretreatment, and the measurement results are easily affected by particle agglomeration and poor sample dispersion.

[0004] In the above context, how to effectively process and disperse fly ash samples, accurately measure their particle size distribution, and calculate their specific surface area has become an urgent problem to be solved in the existing technology. In order to improve the precision and efficiency of fly ash particle size analysis, an improved method and system are needed, which can accurately measure and calculate the particle size distribution and specific surface area of fly ash on the basis of ensuring uniform dispersion of the sample.

[0005] The present invention proposes a method and system for analyzing the particle size of fly ash. By fully drying and dispersing the fly ash samples, combining laser particle size analysis and image analysis technologies, the particle size distribution of the samples is accurately measured. At the same time, by using the cumulative distribution curve and the specific surface area calculation formula, the accuracy of the analysis and the repeatability of the results are further improved. The system of the present invention also has an automatic operation function, which can realize the automatic processing, measurement, and data analysis of samples, greatly improving the work efficiency and reducing the errors that may be brought by manual operation.

[0006] Compared with the traditional technology, the fly ash particle size analysis method of the present invention has achieved significant improvements in the following aspects:

[0007] Sample processing is more optimized: By strictly controlling the drying conditions and dispersion processing parameters, it is ensured that the measurement of the particle size distribution of the fly ash sample is not affected by particle agglomeration and moisture residue, thereby improving the measurement accuracy.

[0008] Data processing is more precise: Using the cumulative distribution curve to calculate the median particle size and specific surface area, and determining the number of particles in the particle size range through image analysis method, which enhances the reliability of the measurement results.

[0009] The system automation level is improved: The system of the present invention integrates the full-process automated operations of sample processing, particle size measurement, data analysis and result output, can process a large number of samples, and significantly improves the analysis efficiency and data consistency.

[0010] The present invention is not only applicable to the particle size analysis of conventional fly ash, but also can be widely applied to the particle size determination of other fine particle substances, providing more reliable and efficient technical support for industrial production and scientific research. Through the accurate measurement of the particle size distribution and specific surface area of fly ash, the present invention will help to further expand the application fields of fly ash and enhance its value of resource utilization. Summary of the Invention

[0011] The purpose of the present invention is to provide a fly ash particle size analysis method and system in view of the deficiencies of the existing technology to solve the problems raised in the background technology.

[0012] To achieve the above purpose, the present invention provides the following technical solutions: The present invention proposes a fly ash particle size analysis method, including the following steps:

[0013] Sample preparation: Collect and uniformly mix the fly ash sample, and perform drying treatment on the sample to make its water content less than 0.5%, so as to eliminate the interference of moisture on the particle size measurement;

[0014] Sample dispersion: Use an ultrasonic disperser or an air flow disperser to disperse the dried fly ash sample, so that the particles are uniformly dispersed in the measurement medium to avoid particle agglomeration;

[0015] Particle size measurement: Feed the dispersed sample into a laser particle size analyzer or an image analysis device to measure the particle size distribution data of the fly ash sample;

[0016] Data processing: Process the data based on the particle size measurement results. The data processing includes: constructing a cumulative distribution curve, determining the median particle size and calculating the specific surface area;

[0017] Among them, constructing a cumulative distribution curve: Based on the particle size measurement results, calculate the volume V of each particle size rangei Sum them up and construct the cumulative distribution curve CDF(d) of the particle size.

[0018]

[0019] Among them, CDF(d) represents the cumulative volume distribution at the particle size d, and V i represents the volume of the i-th particle size interval, and V total is the total volume of the sample. j refers to the serial number of the particle size interval currently added during the calculation of the cumulative distribution curve, indicating that it is cumulatively added from the first interval i = 1 to the j-th interval.

[0020] Determination of the median particle size: According to the cumulative distribution curve, determine the particle size D v(50) corresponding to 50% cumulative volume distribution, that is, the particle size that satisfies CDF(D v(50) ) = 0.5.

[0021] Result output: Generate and output the particle size distribution curve, cumulative distribution data, median particle size D v(50) , specific surface area S BET parameters to form a complete analysis report.

[0022] As a preferred technical solution of the present invention, the temperature of the drying treatment is controlled between 100°C and 120°C, and the drying time is 1 to 2 hours to ensure that the water content of the fly ash sample is less than 0.5%.

[0023] As a preferred technical solution of the present invention, the working frequency of the ultrasonic disperser is 20 to 40 kHz, and the dispersion time is 5 to 10 minutes; the air flow rate of the air flow disperser is 1 to 2 m / s, and the dispersion time is 3 to 5 minutes.

[0024] As a preferred technical solution of the present invention, in the particle size measurement step, a laser particle size analyzer is used, and the measurement range is 0.1 to 1000 microns, preferably 0.5 to 500 microns. The measurement results include the cumulative curve and volume distribution curve of the particle size distribution.

[0025] As a preferred technical solution of the present invention, the specific surface area is calculated using the formula to calculate the specific surface area S BET ;

[0026] Among them: S BET represents the specific surface area, ρ is the density of fly ash, and D mean is the average particle size calculated through the cumulative distribution curve.

[0027] As a preferred technical solution of the present invention, the average particle size D mean calculated through the cumulative distribution curve:

[0028]

[0029] Calculate the average particle size D of the sample mean , where d i is the particle size of the i-th particle size interval, and n i is the number of particles in the corresponding particle size interval.

[0030] As a preferred technical solution of the present invention, the report generated by the result output step includes key parameters such as particle size distribution curve, cumulative distribution curve, median particle size D v(50) , average particle size D mean , specific surface area S BET and so on. The report is output remotely through the network or stored in the database for long-term monitoring and data comparison and analysis.

[0031] The present invention also provides a system for fly ash particle size analysis, including:

[0032] Sample processing module: including a drying device, an ultrasonic disperser or an air flow disperser, for drying and dispersing the fly ash sample;

[0033] Particle size measurement module: including a laser particle size analyzer or an image analysis device, for measuring the particle size distribution of the fly ash sample and generating particle size distribution data;

[0034] Data processing module: including special software, for processing the measurement data, calculating the median particle size D v(50) , average particle size D mean , specific surface area S BET , cumulative distribution curve CDF(d) parameters, and generating an analysis report;

[0035] Result output module: for outputting and storing the analysis results, supporting data storage, report generation and remote access functions.

[0036] As a preferred technical solution of the present invention, the system has an automatic operation function, can automatically complete the whole process of sample processing, particle size measurement, data processing and result output, and can monitor the key parameters in the analysis process in real time to improve the measurement accuracy and efficiency.

[0037] Compared with the prior art, the beneficial effects of the present invention are: improving the accuracy and stability of particle size analysis: by optimizing the drying and dispersing treatment steps of the fly ash sample, the present invention significantly reduces the influence of moisture residue and particle agglomeration in the sample on the measurement results.

[0038] By adopting strictly controlled drying temperature and time to ensure that the water content of the sample is below 0.5%, combined with ultrasonic dispersion or air flow dispersion technology, the particles are evenly dispersed in the measuring medium, thus improving the accuracy of particle size distribution measurement. Whether it is for coarse particles or fine particles of fly ash, the method of the present invention can provide stable and reliable particle size distribution data, effectively reducing measurement errors and data fluctuations.

[0039] Enhance the accuracy of data processing and the depth of analysis: The present invention introduces innovative algorithms for cumulative distribution curve and specific surface area calculation, making the calculation of median particle size D v(50) and specific surface area S BET more accurate. In addition, by determining the number of particles in each particle size range through image analysis method, the calculation accuracy of particle size distribution and average particle size D mean is further improved. These improvements make the analysis results of particle size distribution and specific surface area of fly ash samples more reliable, providing strong data support for subsequent industrial applications.

[0040] Achieve the automation and high efficiency of system operation: The fly ash particle size analysis system of the present invention integrates a fully automated operation process of sample processing, particle size measurement, data processing and result output. The system can automatically complete the analysis of a large number of samples, significantly improving work efficiency and ensuring data consistency and repeatability. In addition, the system supports remote output and storage of data, enabling the analysis results to be applied to production and scientific research in a timely manner. This highly automated design not only reduces errors caused by manual operation, but also greatly improves the accuracy and efficiency of analysis, and is applicable to the rapid analysis of various fly ashes and other fine particle substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a method flow chart of a method for fly ash particle size analysis proposed by the present invention;

[0042] Figure 2 is a system block diagram of a fly ash particle size analysis system proposed by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] The following will describe the specific embodiments of the present invention in detail in conjunction with the accompanying drawings and multiple embodiments.

[0045] Refer to Figure 1And Figure 2 , the present invention provides a method and system for analyzing the particle size of fly ash. Through precise measurement and data processing, important parameters such as the particle size distribution and specific surface area of fly ash can be effectively obtained. The following will combine multiple specific embodiments to detail the application and operation of the present invention.

[0046] Embodiment 1: Standard method for analyzing the particle size of fly ash

[0047] Step 1: Sample preparation

[0048] Collect 200 grams of fly ash samples from a certain coal-fired power plant.

[0049] To ensure the representativeness of the sample, first mix the sample evenly, and then take out 50 grams for analysis. To eliminate the influence of moisture on particle size measurement, place the sample in a vacuum drying oven and dry it at a temperature of 105 °C for 1.5 hours until the water content of the sample is less than 0.5%.

[0050] Step 2: Sample dispersion

[0051] Take out the dried fly ash sample and perform dispersion treatment using an ultrasonic disperser.

[0052] Set the working frequency of the disperser to 35 kHz and the dispersion time to 8 minutes. To ensure the dispersion effect, use a magnetic stirrer to keep the sample evenly distributed during the dispersion process to avoid particle agglomeration.

[0053] Step 3: Particle size measurement

[0054] The dispersed sample is immediately sent to a laser particle size analyzer for particle size measurement. The measurement range set by the instrument is 0.1 to 1000 microns, and the particularly preferred range is 0.5 to 500 microns.

[0055] Through the principle of laser scattering, the instrument measures and automatically generates the cumulative curve and volume distribution curve of the particle size distribution.

[0056] Step 4: Data processing

[0057] Process the measurement data. First, calculate the volume V of each particle size interval i , and use the formula to construct the cumulative distribution curve.

[0058] where j represents the number of the current particle size interval accumulated up to, and V total is the total volume of the sample.

[0059] Determine the particle size D corresponding to the 50% cumulative volume distribution through the cumulative distribution curve v(50) , satisfying CDF(D v(50) ) = 0.5.

[0060] Use the formula to calculate the specific surface area S BET , where D mean is the average particle size calculated from the cumulative distribution curve, and ρ is the density of fly ash, usually 2.6 g / cm³.

[0061] Step 5: The analysis report generated by the result output system includes the particle size distribution curve, cumulative distribution data, median particle size D v(50) , average particle size D mean and specific surface area S BeT .

[0062] The report is remotely output via the network and stored in the database for further analysis and comparison.

[0063] Results and analysis: The test results show that the median particle size of the sample is 18.2 μm, the average particle size is 19.8 μm, and the specific surface area is 430 m 2 / kg². These data provide an important reference for evaluating the application of fly ash in concrete additives.

[0064] Example 2: Analysis of fly ash particle size under different drying conditions

[0065] Objective: To explore the influence of different drying temperatures and times on the measurement results of fly ash particle size.

[0066] Steps: Take three fly ash samples of the same batch, each sample weighing 50 grams, and process them under different drying conditions:

[0067] Sample A: Dry at 105°C for 2 hours;

[0068] Sample B: Dry at 120°C for 1.5 hours;

[0069] Sample C: Dry at 80°C for 3 hours.

[0070] Process and analyze each sample using the same dispersion and particle size measurement procedures.

[0071] Results and analysis: The median particle size of Sample A is 18.2 μm, and the average particle size is 19.8 μm; the median particle size of Sample B is 18.0 μm, and the average particle size is 19.5 μm; the median particle size of Sample C is 18.5 μm, and the average particle size is 20.1 μm.

[0072] The results show that different drying temperatures and times have little effect on the particle size distribution of fly ash, but too high a temperature (such as 120°C) may cause agglomeration of some particles, slightly reducing the median and average particle sizes. A long drying time at a low temperature (such as 80°C for 3 hours) may make the particles more dispersed.

[0073] Example 3: Comparison of Particle Size Distributions of Fly Ash from Different Sources

[0074] Objective: To evaluate the differences in particle size distribution and specific surface area of fly ash samples from different power plants to guide their different applications.

[0075] Steps: Collect fly ash samples from three power plants (A, B, and C) respectively. Treat 50 grams of each sample and analyze them according to the standard operating procedure in Example 1.

[0076] Sample from Power Plant A: Median particle size D v(50) is 16.5 microns, average particle size D mean is 18.0 microns, specific surface area S BET is 420 m 2 / kg°

[0077] Sample from Power Plant B: Median particle size D v(50) is 12.8 microns, average particle size D mean is 15.2 microns, specific surface area S BET is 500 m 2 / kg°

[0078] Sample from Power Plant C: Median particle size D v(50) is 20.0 microns, average particle size D mean is 21.5 microns, specific surface area S BEt is 390 m 2 / kg°

[0079] Results and Analysis: The analysis results show that there are significant differences in the particle size distributions of fly ash from different power plants. The sample from Power Plant B has a smaller particle size and a larger specific surface area, making it suitable for use as a concrete additive or adsorbent material. The sample from Power Plant C has a larger particle size and may be more suitable for use as a foundation filler or in brick and tile manufacturing.

[0080] Example 4: Automated Testing of Fly Ash Particle Size Analysis System

[0081] Objective: To test the automated analysis ability and data stability of the system, especially its performance when processing a large number of samples.

[0082] Steps: Analyze 50 fly ash samples from different batches, with each sample being about 50 grams. The system uses an automatic sampling device to automatically complete the processes of drying, dispersion, measurement, and data processing.

[0083] Record the processing time of each sample and the stability of the measurement results.

[0084] Results and Analysis: In the automatic mode, the average processing time for each sample is 6 minutes. The standard deviation of the median particle size data for all samples is less than 0.3%, and the variation range of the specific surface area is within 2%.

[0085] In addition, the system exhibits good stability and reliability during long-term operation, making it suitable for large-scale industrial applications and scientific research experiments.

[0086] Example 5: Study on the Correlation between Specific Surface Area and Application Performance of Fly Ash

[0087] Objective: By measuring the specific surface area of fly ash, study its application performance in concrete and adsorption materials.

[0088] Steps: Select three representative fly ash samples, and measure their particle size distributions and specific surface areas respectively. Then, incorporate these samples into concrete respectively, and measure their effects on the compressive strength of concrete. At the same time, apply the samples to wastewater adsorption experiments to evaluate their adsorption effects on heavy metal ions.

[0089] Results and Analysis: Samples with a large specific surface area (such as Sample B with a specific surface area of 500 m2 / kg) show better strengthening effects in concrete, increasing the compressive strength of concrete by 15%; while in the adsorption experiment, the adsorption rate of this sample for heavy metal ions (such as lead ions) reaches 85%.

[0090] Samples with a smaller specific surface area (such as Sample C with a specific surface area of 390 m2 / kg) have weaker strengthening effects in concrete, only increasing the compressive strength by 5%, but show better fluidity and compactability in the application of foundation fillers.

[0091] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for analyzing fly ash particle size, characterized in that: The following steps are involved: Sample preparation: Collect and evenly mix the fly ash samples, and dry the samples to make their moisture content less than 0.5%; Sample dispersion: Use an ultrasonic disperser or airflow disperser to disperse the dried fly ash sample so that the particles are evenly dispersed in the measuring medium to avoid particle agglomeration; Particle size measurement: send the dispersed sample into a laser particle size analyzer or image analysis equipment to measure the particle size distribution data of the fly ash sample; Data processing: Data is processed based on the particle size measurement results. Data processing includes: cumulative distribution curve construction, median particle size determination and specific surface area calculation; Among them, the cumulative distribution curve is constructed: based on the particle size measurement results, the volume V of each particle size interval is calculated i And accumulate to construct the cumulative distribution curve CDF(d) of particle size. Wherein, CDF(d) represents the cumulative volume distribution at particle size d, V i represents the volume of the i-th particle size interval, V total is the total volume of the sample, j refers to the number of the particle size interval currently accumulated when calculating the cumulative distribution curve, indicating accumulation from the first interval i=1 to the jth interval; Determination of median particle size: According to the cumulative distribution curve, determine the particle size D corresponding to 50% cumulative volume distribution v(50) , that is, satisfying CDF(D v(50) )=0.5 particle size; Result output: Generate and output particle size distribution curve, cumulative distribution data, median particle size D v(50) , specific surface area S BET parameters to form a complete analysis report.

2. The fly ash particle size analysis method according to claim 1, characterized in that: The temperature of the drying process is controlled between 100° C. and 120° C., and the drying time is 1 to 2 hours to ensure that the water content of the fly ash sample is less than 0.5%.

3. The fly ash particle size analysis method according to claim 1, characterized in that: The working frequency of the ultrasonic disperser is 20 to 40 kHz, and the dispersion time is 5 to 10 minutes; the air flow velocity of the air flow disperser is 1 to 2 m / s, and the dispersion time is 3 to 5 minutes.

4. The fly ash particle size analysis method according to claim 1, characterized in that: The particle size measurement step uses a laser particle size analyzer with a measurement range of 0.1 to 1000 microns, preferably 0.5 to 500 microns. The measurement results include a cumulative curve of particle size distribution and a volume distribution curve.

5. The fly ash particle size analysis method according to claim 1, characterized in that: The specific surface area is calculated using the formula: Calculate the specific surface area S BET Where: d BET represents the specific surface area, ρ is the density of fly ash, D mean is the average particle size calculated by the cumulative distribution curve.

6. The fly ash particle size analysis method according to claim 5, characterized in that: The D mean The average particle size calculated by the cumulative distribution curve: Calculate the average particle size D of the sample mean , where d i is the particle size of the ith particle size interval, n i is the number of particles in the corresponding particle size range.

7. The fly ash particle size analysis method according to claim 1, characterized in that: The report generated in the result output step includes a particle size distribution curve, a cumulative distribution curve, a median particle size D v(50) , average particle size D mean , specific surface area S BET Key parameters and reports are remotely output via the network or stored in a database to facilitate long-term monitoring and data comparison and analysis.

8. A system for fly ash particle size analysis, characterized in that: include: Sample processing module: including a drying device, an ultrasonic disperser or an air flow disperser, used for drying and dispersing fly ash samples, and the drying device adopts an oven; Particle size measurement module: including a laser particle size analyzer or an image analysis device, used to measure the particle size distribution of the fly ash sample and generate particle size distribution data; Data processing module: includes dedicated software for processing measurement data and calculating median particle size D v(50) , average particle size D mean , specific surface area S BET , cumulative distribution curve CDF(d) parameters, and generate analysis reports; Result output module: used to output and store analysis results, supporting data storage, report generation and remote access functions.

9. The system for fly ash particle size analysis according to claim 8, characterized in that: The system has an automated operation function and can automatically complete the entire process of sample processing, particle size measurement, data processing and result output, and can monitor key parameters in the analysis process in real time to improve the accuracy and efficiency of the measurement.

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