Fly ash particle size analysis method and system

Abstract

According to the fly ash particle size analysis method and system provided by the invention, the particle size distribution of a fly ash sample is accurately measured by optimizing sample drying and dispersing treatment and combining laser particle size analysis and image analysis technologies. The method comprises the following steps: drying a sample to ensure that the water content is lower than 0.5%; uniformly dispersing the particles by using an ultrasonic or airflow dispersion technology; measuring the particle size by adopting a laser particle size analyzer, and generating a cumulative distribution curve; and calculating the median particle size and the specific surface area through the cumulative distribution curve. The system has an automatic operation function, and can automatically complete sample treatment, particle size measurement, data analysis and result output. According to the method, the measurement accuracy and the data processing precision are improved, and the method is suitable for efficient analysis of large-batch samples and has a wide industrial application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, in particular to a fly ash particle size analysis method and system. Background Art

[0002] Fly ash is a fine particle 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 building materials, road paving, environmental protection engineering and other fields. However, the physical and chemical properties of fly ash, such as particle size distribution and specific surface area, directly affect its application effect in these fields. Therefore, accurate measurement and analysis of the particle size distribution and specific surface area of ​​fly ash are of great significance to improve the utilization efficiency of fly ash.

[0003] At present, the particle size analysis methods of fly ash mainly include screening method, sedimentation method, laser particle size analysis method and image analysis method. Among them, the screening method is widely used in the particle size analysis of coarse particle powder due to its simple operation. However, for fine particle materials such as fly ash, the screening method has low accuracy and it is difficult to accurately measure the particle size distribution. The sedimentation method estimates the particle size by the sedimentation velocity of particles in the 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 of particles through the principle of laser scattering. It has high accuracy 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 prior art. In order to improve the accuracy and efficiency of fly ash particle size analysis, an improved method and system are needed that can accurately measure and calculate the particle size distribution and specific surface area of ​​fly ash while ensuring uniform dispersion of the sample.

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

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

[0007] More optimized sample processing: By strictly controlling the drying conditions and dispersion processing parameters, the particle size distribution measurement of the fly ash sample is ensured not to be affected by particle agglomeration and residual moisture, thereby improving the accuracy of the measurement.

[0008] More accurate data processing: The median particle size and specific surface area are calculated using the cumulative distribution curve, and the number of particles in the particle size range is determined by image analysis, which enhances the reliability of the measurement results.

[0009] Improved system automation level: The system of the present invention integrates the full-process automated operation of sample processing, particle size measurement, data analysis and result output, and can process large batches of samples, significantly improving analysis efficiency and data consistency.

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

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

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

[0013] Sample preparation: Collect and evenly mix fly ash samples, and dry the samples to make their moisture content less than 0.5% to eliminate the interference of moisture on particle size measurement;

[0014] 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;

[0015] 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;

[0016] 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;

[0017] Among them, the cumulative distribution curve is constructed: based on the particle size measurement results, the volume V of each particle size interval is calculatedi And accumulate to construct the cumulative distribution curve CDF(d) of particle size.

[0018]

[0019] 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;

[0020] 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;

[0021] 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.

[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 velocity 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, a laser particle size analyzer is used in the particle size measurement step, and the measurement range is 0.1 to 1000 microns, preferably 0.5 to 500 microns, and the measurement results include a cumulative curve of particle size distribution and a volume distribution curve.

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

[0026] Where: S 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.

[0027] As a preferred technical solution of the present invention, the D mean The average particle size calculated by 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 ith particle size interval, n i is the number of particles in the corresponding particle size range.

[0030] As a preferred technical solution of the present invention, 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 The report can be remotely output via the network or stored in the database to facilitate long-term monitoring and data comparison and analysis.

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

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

[0033] 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;

[0034] 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;

[0035] Result output module: used to output and store 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 automated operation function, 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 measurement accuracy and efficiency.

[0037] Compared with the prior art, the present invention has the following beneficial effects: improving the accuracy and stability of particle size analysis: the present invention significantly reduces the influence of residual moisture and particle agglomeration in the sample on the measurement result by optimizing the drying and dispersion processing steps of the fly ash sample.

[0038] Strictly controlled drying temperature and time are used to ensure that the sample moisture content is less than 0.5%, and combined with ultrasonic dispersion or airflow dispersion technology, the particles are evenly dispersed in the measuring medium, thereby improving the accuracy of particle size distribution measurement. Whether it is 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] Enhanced data processing accuracy and analysis depth: This invention introduces innovative algorithms for cumulative distribution curve and specific surface area calculation, making the median particle size D v(50) and specific surface area S BET In addition, the number of particles in each particle size range is determined by image analysis, which further improves the particle size distribution and average particle size D mean These improvements make the analysis results of the particle size distribution and specific surface area of ​​fly ash samples more reliable, providing strong data support for subsequent industrial applications.

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

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

[0042] Figure 2 The present invention provides a system block diagram of a fly ash particle size analysis system. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings and multiple embodiments.

[0045] See also Figure 1and Figure 2 The present invention provides a fly ash particle size analysis method and system, which can effectively obtain important parameters such as fly ash particle size distribution and specific surface area through accurate measurement and data processing. The application and operation of the present invention will be described in detail below in conjunction with multiple specific embodiments.

[0046] Example 1: Standard fly ash particle size analysis method

[0047] Step 1: Sample preparation

[0048] 200 g of fly ash sample was collected from a coal-fired power plant.

[0049] To ensure the representativeness of the sample, the sample was first mixed evenly, and then 50 grams were taken out for analysis. In order to eliminate the influence of moisture on the particle size measurement, the sample was placed in a vacuum drying oven and dried at 105°C for 1.5 hours until the moisture content of the sample was less than 0.5%.

[0050] Step 2: Sample dispersion

[0051] The dried fly ash sample was taken out and dispersed using an ultrasonic disperser.

[0052] The operating frequency of the disperser was set to 35 kHz and the dispersion time was set to 8 minutes. In order to ensure the dispersion effect, a magnetic stirrer was used during the dispersion process to keep the sample evenly distributed and 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 instrument is set to measure in a range of 0.1 to 1000 microns, and a 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 particle size distribution.

[0056] Step 4: Data Processing

[0057] The measured data is processed by first calculating the volume V of each particle size interval. i , and use the formula Construct a cumulative distribution curve.

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

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

[0060] Using the formula Calculate the specific surface area S BET , where D mean is the average particle size calculated by the cumulative distribution curve, and ρ is the density of fly ash, which is usually 2.6 g / cm'.

[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] Reports are remotely exported via the network and stored in a 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 microns, the average particle size is 19.8 microns, and the specific surface area is 430m 2 / kg°. 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 effects of different drying temperatures and times on the measurement of fly ash particle size.

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

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

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

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

[0070] Each sample was processed and analyzed using the same dispersion and particle size measurement procedures.

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

[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 some particles to agglomerate, slightly reducing the median and average particle sizes. Low-temperature treatment with a longer drying time (such as 80°C, 3 hours) may make the particles more dispersed.

[0073] Example 3: Comparison of particle size distribution 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 uses.

[0075] Procedure: Fly ash samples were collected from three power plants (A, B, and C), 50 grams of each sample was processed, and the analysis was performed according to the standard operating procedure of Example 1.

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

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

[0078] Sample from power plant C: median particle size D v(50) The average particle size D is 20.0 microns. mean The specific surface area is 21.5 microns. BEt 390m 2 / kg°

[0079] Results and analysis: The analysis results show that there are significant differences in the particle size distribution of fly ash from different power plants. The samples from Power Plant B have smaller particle sizes and larger specific surface areas, making them suitable for use as concrete additives or adsorption materials; the samples from Power Plant C have larger particle sizes and may be more suitable for foundation fillers or brick and tile manufacturing.

[0080] Example 4: Automated testing of fly ash particle size analysis system

[0081] Purpose: To test the system's automated analysis capabilities and data stability, especially when processing a large number of samples.

[0082] Steps: 50 fly ash samples from different batches were analyzed, each sample was about 50 grams. The system used an automatic sample feeder to automatically complete the drying, dispersion, measurement and data processing processes.

[0083] The processing time and stability of the measurement results were recorded for each sample.

[0084] Results and analysis: When the system is in automatic mode, the average processing time for each sample is 6 minutes, the standard deviation of the median particle size data of 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 and is 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: To study the application performance of fly ash in concrete and adsorption materials by measuring its specific surface area.

[0088] Steps: Select three representative fly ash samples and measure their particle size distribution and specific surface area. Then, add these samples to concrete and measure their effects on concrete compressive strength. 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 ​​500m2 / kg) showed better reinforcement effects in concrete, increasing the compressive strength of concrete by 15%; and in the adsorption experiment, the adsorption rate of the sample for heavy metal ions (such as lead ions) reached 85%.

[0090] Samples with a smaller specific surface area (such as sample C, with a specific surface area of ​​390 m2 / kg) have a weaker concrete reinforcement effect, only increasing the compressive strength by 5%, but show better fluidity and compactibility in foundation filler applications.

[0091] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in 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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