Calcium carbonate powder chromaticity detection method

Abstract

The invention relates to the technical field of material science and engineering, and discloses a calcium carbonate powder chromaticity detection method, which comprises the following steps of: collecting samples from vertical and horizontal directions by using a tool according to a layering and zoning principle, classifying, pretreating the samples, measuring the samples by using a colorimeter, averaging, and detecting the state of a monitoring instrument; the method comprises the following steps: detecting the chromaticity of the calcium carbonate powder by using a visual colorimetric method, re-detecting or replacing an instrument when the chromaticity is abnormal, switching the visual colorimetric method when the instrument detects the abnormity, operating by multiple persons, and finally comprehensively analyzing the two types of detection data, thereby ensuring that the calcium carbonate powder can obtain accurate chromaticity detection results under different conditions by combining the dual detection means of the instrument detection and the visual colorimetric method; in the instrument detection process, through a real-time monitoring and fault processing mechanism, the abnormal condition of the instrument can be effectively handled, the stability of detection data is ensured, meanwhile, the visual colorimetric method serves as an auxiliary means, reliable reference can be provided when the detection result of the instrument has questions, and the accuracy of the detection result is further verified.

Description

Technical Field

[0001] The invention relates to the field of material science and engineering technology, and in particular to a method for detecting the colorimetry of calcium carbonate powder. Background Art

[0002] In modern industrial production, calcium carbonate powder, as an important inorganic non-metallic material, is widely used in rubber, plastics, papermaking, and coatings. Its color index not only directly affects the appearance quality of the product, but also the quality and performance of downstream applications. Therefore, accurate color measurement of calcium carbonate powder is crucial.

[0003] However, existing methods for colorimetric detection of calcium carbonate powders have many limitations. In the sample collection process, traditional methods cannot guarantee the representativeness of the samples taken for the entire powder, and cannot fully reflect the colorimetric characteristics of different depths and regions, which can easily lead to deviations in the test results; in the sample pretreatment process, there is a lack of standardized and unified processing procedures, and the sample particles are uneven and unstable, which will interfere with the accuracy of subsequent tests. In terms of instrument detection, most methods lack real-time monitoring of the instrument's operating status and an effective fault handling mechanism. When the instrument has a light source failure, communication anomalies, or data fluctuations, it is difficult to ensure the stability and reliability of the test data. In addition, the existing detection process lacks standardization, the data processing method is single, it is difficult to quickly identify problems in the detection process, and the original data and correction records lack systematic archiving, which is not conducive to quality traceability and optimization of the detection process.

[0004] Therefore, there is an urgent need for a colorimetric detection method for calcium carbonate powder that can solve the above problems and achieve accurate, stable and efficient detection to meet the strict requirements of industrial production for product quality control. Summary of the Invention (1) Technical problems solved

[0005] In response to the shortcomings of the existing technology, the present invention provides a method for detecting the colorimetry of calcium carbonate powder, which has the advantages of high accuracy, strong adaptability and standardized operation, and solves the problems of insufficient sample representativeness, poor instrument detection stability and imperfect data processing and correction mechanism in the existing detection methods. (2) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solution: a method for detecting the colorimetry of calcium carbonate powder, comprising the following detection steps: Step 1: Sample collection: Use sampling tools to collect samples vertically and horizontally in the calcium carbonate powder storage area, following the principles of stratification and zoning. After sample classification, the samples to be tested are obtained. Step 2: Sample pretreatment: Dry, grind and allow the sample to stand; Step 3: Sample colorimetry: Align the calibrated colorimeter’s measuring aperture with different locations on the surface of the sample after it has rested, and take the average value of all the measurements. Step 4. Monitor the instrument testing process: During the instrument testing process, observe the instrument's operating status and measurement data in real time. If there are large fluctuations in the measurement data or instrument errors, stop the test immediately, check the colorimeter connection and sample status, recalibrate the instrument, and retest the sample. If the retest results are still abnormal, replace the instrument with the same type or send it to a professional institution for testing. Step 5. Switch to visual colorimetry: When instrument detection cannot be performed normally or there are doubts about the instrument detection results, switch to visual colorimetry as an auxiliary detection method; Step 6. Visual process monitoring: During the visual colorimetry process, arrange two or more testers to perform the colorimetry operation independently and record their respective colorimetry results; Step 7. Data processing and correction throughout the entire process: After the test is completed, record the test data and conduct a comprehensive analysis of the instrument test data and visual colorimetry results.

[0007] Preferably, the sample collection tool in step 1 is: (1) Vertical sampling tools: retractable sampling tube and powder sampler; (2) Horizontal sampling tools: surface scraper and partition sampling shovel.

[0008] Preferably, the sample collection process in step 1: S1.1. In the vertical direction: Use a retractable sampling tube and powder sampler to collect samples from three different depths of the powder pile: the top, middle, and bottom. S1.2. Horizontally: Use a surface scraper and a partitioned sampling shovel to collect calcium carbonate powder samples from the edge, center, and lower areas of the powder pile. Collect 3 to 5 parallel subsamples from each area. S1.3. Sample reduction: Mix the collected sub-samples evenly and use the quartering method to reduce them to 500-600g as the samples to be tested.

[0009] Preferably, the sample pretreatment process in step 2 is: S2.1. Dry the sample in a constant temperature drying oven at 105-110°C for 2-4 hours. S2.2. After drying, transfer the sample to be tested into a mortar and grind until it passes through a 200-300 mesh sieve; S2.3. Place the ground sample in portions of 50 to 100 g into clean, dry, light-proof sealed containers and let them stand for 24 to 36 hours.

[0010] Preferably, the colorimeter parameters in step 3 are set as follows: using D65 standard light source as the measurement light source, a measurement aperture of 8 mm or 11 mm, and a number of measurements of 3 to 5 times.

[0011] Preferably, the sample colorimetry detection process in step 3 is: S3.1. Use a colorimeter as a colorimetric instrument. Before testing, calibrate the instrument using a standard white plate according to the instrument's operating manual. S3.2. Align the calibrated instrument measurement aperture with the sample surface, evenly select 5 to 7 different locations on the sample surface for measurement, record the brightness, red-green axis, and yellow-blue axis values ​​at each location, and take the average value of the measurements at all locations as the instrument detection chromaticity result for the sample.

[0012] Preferably, the situation in which the measurement data fluctuates too much in step 4 is: the difference between two adjacent measurement values ​​exceeds a set threshold, the brightness value fluctuates by more than 2, and the red-green axis or yellow-blue axis value fluctuates by more than 1.

[0013] Preferably, the visual colorimetry method in step 5: S5.1. Prepare a set of standard calcium carbonate powder colorimetric cards; S5.2. In a colorimetric box under standard lighting conditions, compare the sample to be tested with the colorimetric card; S5.3. When observing, keep your eyes 20 to 30 cm away from the sample and the colorimetric card, with your line of sight perpendicular to the sample and the card surface. Observe and compare from angles of 30°, 60°, and 90° to obtain the final chromaticity grade.

[0014] Preferably, in the visual process monitoring of step six, when the difference between the results of two inspectors exceeds one chromaticity level, an additional inspector is added to perform colorimetry, and the results of the majority of inspectors are taken as the standard. At the same time, the entire visual colorimetry process is video recorded for subsequent tracing and review.

[0015] Preferably, the whole process of data processing and correction in step seven is as follows: S7.1. After the test is completed, conduct a comprehensive analysis of the instrument test data and visual colorimetric results; S7.2. When the results of the two test methods are similar, where the deviation between the brightness value of the instrument test and the brightness value of the standard sample corresponding to the visual colorimetry is within ±2, and the deviation between the red-green axis and the yellow-blue axis is within ±1, the instrument test result shall be used as the final color test result of the calcium carbonate powder; S7.3. When the results differ significantly, re-examine the sample pretreatment process, the instrument status, and the visual colorimetry environment, analyze the causes of the discrepancies, and correct the problematic steps before retesting. S7.4. Finally, organize and archive the original data, analysis results and correction records during the testing process.

[0016] Compared with the prior art, the present invention provides a method for detecting the colorimetry of calcium carbonate powder, which has the following beneficial effects: 1. The present invention can ensure that the colorimetric detection results of calcium carbonate powder can be obtained accurately under different conditions through instrument detection. During the instrument detection process, through real-time monitoring and fault handling mechanism, it can effectively deal with instrument abnormalities and ensure the stability of detection data.

[0017] 2. The present invention ensures that the samples are fully representative through a layered and zoned sampling method, which can reflect the chromaticity characteristics of calcium carbonate powder at different depths and regions. At the same time, by optimizing the sample pretreatment steps, such as drying, grinding and static treatment, the sample particles are made uniform and stable, reducing the detection error caused by sample unevenness.

[0018] 3. The present invention ensures the efficiency and consistency of the detection process through standardized detection procedures and data processing methods. In the data processing and correction link, by comprehensively analyzing the instrument detection data and visual colorimetry results, problems in the detection process can be quickly identified and corrected, avoiding repeated detection and invalid operations. At the same time, the original data, analysis results and correction records in the detection process are organized and archived for subsequent reference and quality traceability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 2. It is a diagram of the detection steps of the method of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0021] See also Figure 1 A method for detecting the colorimetry of calcium carbonate powder comprises the following steps: Step 1: Sample collection: Use clean and dry sampling tools to ensure that the samples are not contaminated. In the calcium carbonate powder storage area, follow the principles of stratification and zoning, collect samples from vertical and horizontal directions, and obtain the samples to be tested after classification to ensure that the samples taken are fully representative; Step 2: Sample pretreatment: Dry, grind and allow the sample to stand to ensure that the particles are evenly distributed and stable. Step 3: Sample colorimetry: Align the calibrated colorimeter’s measuring aperture with different locations on the surface of the sample after it has rested, and take the average value of all the measurements. Step 4. Monitor the instrument testing process: During the instrument testing process, observe the instrument's operating status and measurement data in real time. If there are large fluctuations in the measurement data or instrument errors, stop the test immediately, check the colorimeter connection and sample status, recalibrate the instrument, and retest the sample. If the retest results are still abnormal, replace the instrument with the same type or send it to a professional institution for testing. Step 5. Switch to visual colorimetry: When instrument detection cannot be performed normally or there are doubts about the instrument detection results, switch to visual colorimetry as an auxiliary detection method to ensure the continuity of the detection process; Step 6. Visual process monitoring: During the visual colorimetry process, arrange two or more testers to perform the colorimetry operation independently and record their respective colorimetry results; Step 7. Data processing and correction throughout the entire process: After the test is completed, record the test data and conduct a comprehensive analysis of the instrument test data and visual colorimetry results.

[0022] Specifically, the sample collection tool in step 1 is: (1) Vertical sampling tools: retractable sampling tube (the length is customized according to the height of the storage area, ranging from 0.2 to 3 meters, the tube diameter is 2 to 6 centimeters, one end is a sharp bevel for inserting into the powder pile; the other end is equipped with a sealing cap. When in use, the sampling tube is vertically inserted into the bottom, middle and upper layers of the calcium carbonate powder pile, and the retractable sampling tube is used to allow the powder to enter the tube. After the tube is pulled out, the tube mouth is sealed, which can effectively collect samples from each layer, avoid mixing of samples from different layers, and ensure the independence of the layered samples) and a powder sampler (with scale); (2) Horizontal sampling tools: surface scraper (made of stainless steel, with an arc-shaped shovel head, a capacity of 50-100 ml, and a handle length of 30-40 cm, which is convenient for handheld operation) and partition sampling shovel (the shovel body is made of stainless steel, the shovel blade is sharp and straight, which is convenient for cutting into calcium carbonate powder for sampling, and the shovel handle is of moderate length for easy operation).

[0023] Specifically, the sample collection process in step 1: S1.1. In the vertical direction: Use a retractable sampling tube and powder sampler to collect samples from three different depths of the powder pile: the top, middle, and bottom. S1.2. Horizontally: Use a surface scraper and a partitioned sampling shovel to collect calcium carbonate powder samples from the edge, center, and lower areas of the powder pile. Collect 3 to 5 parallel subsamples from each area. S1.3. Sample reduction: Mix the collected sub-samples evenly and use the quartering method to reduce them to 500-600g as the sample to be tested, so as to ensure that the sample is fully representative and can reflect the color characteristics of the entire powder.

[0024] Specifically, the sample pretreatment process in step 2: S2.1. Place the sample to be tested in a constant temperature drying oven at 105-110°C for 2-4 hours to remove moisture from the sample and prevent moisture from interfering with colorimetric detection. S2.2. After drying, transfer the sample to be tested into a mortar and grind until all the particles pass through a 200-300 mesh sieve to make the powder particles uniform and reduce the detection error caused by particle size differences; S2.3. Place the ground sample in portions of 50 to 100 g into clean, dry, light-proof sealed containers and allow them to stand for 24 to 36 hours to allow the particle distribution inside the sample to reach a stable state.

[0025] The advantages are: through the layered and zoned sampling method, the sample is ensured to be fully representative and can reflect the colorimetric characteristics of calcium carbonate powder at different depths and regions. At the same time, by optimizing the sample pretreatment steps, such as drying, grinding and static treatment, the sample particles are made uniform and stable, reducing the detection error caused by sample unevenness.

[0026] Specifically, in step 3, the colorimeter parameters are set as follows: D65 standard light source is used as the measurement light source, the measurement aperture is 8mm or 11mm, and the number of measurements is 3 to 5 to ensure the consistency and comparability of the detection conditions.

[0027] Specifically, the sample colorimetric detection process in step 3: S3.1. Before testing, use a colorimeter as the instrument for colorimetric measurement. Calibrate the instrument using a standard white plate according to the instrument's operating manual to ensure measurement accuracy. S3.2. Align the calibrated instrument measurement aperture with the sample surface, evenly select 5 to 7 different locations on the sample surface for measurement, record the brightness, red-green axis, and yellow-blue axis values ​​at each location, and take the average value of the measurements at all locations as the instrument detection chromaticity result for the sample.

[0028] Specifically, the situation in step 4 where the measurement data fluctuates too much is as follows: the difference between two adjacent measurement values ​​exceeds the set threshold, the brightness value fluctuates by more than 2, and the red-green axis or yellow-blue axis value fluctuates by more than 1; the instrument error conditions include: light source failure and communication abnormality.

[0029] Specifically, the visual colorimetry method in step 5: S5.1. Prepare a set of standard calcium carbonate powder colorimetric cards. The cards should contain standard samples of different color levels and be certified by an authoritative organization. S5.2. In a colorimetric box under standard lighting conditions, compare the sample to be tested with the colorimetric card; S5.3. When observing, keep your eyes 20 to 30 cm away from the sample and the colorimetric card, with your line of sight perpendicular to the sample and the card surface. Observe and compare at angles of 30°, 60°, and 90° to determine the closest chromaticity level between the sample and the colorimetric card.

[0030] Specifically, in step six of the visual process monitoring, if the difference between the results of two inspectors exceeds one chromaticity level, an additional inspector will be added to perform colorimetry, and the results of the majority of inspectors will be taken as the standard. At the same time, the entire visual colorimetry process will be video recorded for subsequent tracing and review.

[0031] Specifically, the whole process of data processing and correction in step seven: S7.1. After the test is completed, conduct a comprehensive analysis of the instrument test data and visual colorimetric results; S7.2. When the results of the two test methods are similar, where the deviation between the brightness value of the instrument test and the brightness value of the standard sample corresponding to the visual colorimetry is within ±2, and the deviation between the red-green axis and the yellow-blue axis is within ±1, the instrument test result shall be used as the final color test result of the calcium carbonate powder; S7.3. When the results differ significantly, re-examine the sample pretreatment process, the instrument status, and the visual colorimetry environment, analyze the causes of the discrepancies, and correct the problematic steps before retesting. S7.4. Finally, the original data, analysis results and correction records of the testing process shall be organized and archived for subsequent reference and quality traceability.

[0032] The advantages are: the present invention can ensure that accurate colorimetric detection results of calcium carbonate powder can be obtained under different conditions by combining the dual detection means of instrument detection and visual colorimetry. During the instrument detection process, through real-time monitoring and fault handling mechanisms, it can effectively deal with instrument abnormalities and ensure the stability of detection data. At the same time, visual colorimetry, as an auxiliary means, can provide a reliable reference when there are doubts about the instrument detection results, and further verify the accuracy of the detection results.

[0033] Based on the above, the detection process of four scenarios is sorted out to verify the reliability of the content of the present invention, and the specific details are: Example 1 (routine sample testing) S1. Sampling process: In the warehouse of a calcium carbonate production enterprise, a customized retractable sampling tube with a length of 2 meters and a diameter of 4 centimeters was used, together with a powder sampler, to conduct vertical sampling from the top (0.5 meters from the top), the middle (the middle of the pile), and the bottom (0.3 meters from the ground) of the powder pile. A surface scraper and a partitioned sampling shovel were used to conduct horizontal sampling at the edge, center, and lower areas of the powder pile. Three sub-samples were collected in each area. After mixing the sub-samples, they were divided into 550g by the quartering method as the samples to be tested.

[0034] S2. Sample testing process: Place the sample in a drying oven at 105°C for 3 hours, grind until it passes through a 250-mesh sieve, and divide it into 80g portions into sealed containers and let it stand for 24 hours. Use a colorimeter equipped with a D65 light source and an 8mm measuring aperture to measure 7 positions on the sample surface after calibration. The average values ​​of the brightness value, red-green axis value, and yellow-blue axis value are 88.2, -0.5, and 1.2, respectively. When visually comparing the color, both inspectors determined that the sample chromaticity was consistent with a certain level on the colorimetric card. The deviation between the instrument detection and the visual colorimetric results was within the allowable range. The final result of the instrument detection shall prevail.

[0035] Example 2 (Instrument Fault Handling and Detection) In the inspection of another batch of calcium carbonate powder, sample collection and pretreatment were completed according to the standard process. When using the colorimeter for inspection, the instrument reported a light source failure error, and the inspection was immediately stopped. The instrument connection was checked and recalibrated and then retested. Abnormalities still occurred. After replacing the colorimeter of the same type, the sample was retested. The average brightness value, red-green axis value, and yellow-blue axis value measured by the new instrument were 87.8, -0.6, and 1.3, respectively. Visual color comparison was performed at the same time. Two of the three inspectors judged that the results were similar to those of the new instrument. Finally, the test results of the new instrument were used as the chromaticity value of the sample, proving that the troubleshooting process is effective.

[0036] Example 3 (Visual colorimetric detection) A batch of calcium carbonate powder suspected of having abnormal color was tested. After sample collection and pretreatment, the data fluctuation during the colorimeter detection process was too large (the brightness value of two adjacent measurements fluctuated by 3). After multiple calibration and retesting, there was still no improvement. The visual colorimetry method was switched to. In a standard colorimetric box, three inspectors observed and compared the sample from angles of 30°, 60°, and 90° respectively. Two of the inspectors believed that the sample color matched a specific level on the colorimetric card. Finally, this level was used as the color determination result of the sample, verifying the reliability of the visual colorimetry method as an auxiliary means.

[0037] Example 4 (Data Difference Analysis and Detection) The same calcium carbonate powder sample was tested according to the process. The instrument detection obtained the average values ​​of brightness, red-green axis value, and yellow-blue axis value of 89.1, -0.3, and 1.0, respectively. The visual colorimetric judgment result corresponded to the standard sample brightness value of 86.5, red-green axis value of -0.8, and yellow-blue axis value of 0.7. The difference exceeded the allowable range. Re-inspection found that the sample drying time was insufficient, resulting in residual moisture affecting the instrument detection. Therefore, the drying time was extended to 4 hours and re-tested. The instrument test results were similar to the visual colorimetric results, proving that the data processing and correction process can effectively troubleshoot problems and ensure the accuracy of detection.

[0038] Summary: Examples 1-4 show that the calcium carbonate powder colorimetry detection method can operate stably in routine detection, instrument failure response, visual colorimetry assistance, and data difference processing detection scenarios. Example 1 demonstrates the accuracy of the method of the present invention under normal circumstances; Example 2 verifies the effectiveness of the instrument failure handling process; Example 3 reflects the reliability of visual colorimetry as an auxiliary means; Example 4 demonstrates the importance of data processing and correction process to ensure the accuracy of the test results. Combining the results of the four examples, the detection method of the present invention has standardized operation and reliable results, can effectively detect the colorimetry of calcium carbonate powder, and provide strong support for product quality control.

[0039] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting the colorimetry of calcium carbonate powder, characterized in that: The following detection steps are included: Step 1: Sample collection: Use sampling tools to collect samples vertically and horizontally in the calcium carbonate powder storage area, following the principles of stratification and zoning. After sample classification, the samples to be tested are obtained. Step 2: Sample pretreatment: Dry, grind and allow the sample to stand; Step 3: Sample colorimetry: Align the calibrated colorimeter’s measuring aperture with different locations on the surface of the sample after it has been left to rest, and take the average value of the measurements at all locations. Step 4. Monitor the instrument testing process: During the instrument testing process, observe the instrument's operating status and measurement data in real time. If there are large fluctuations in the measurement data or instrument errors, stop the test immediately, check the colorimeter connection and sample status, recalibrate the instrument, and retest the sample. If the retest results are still abnormal, replace the instrument with the same type or send it to a professional institution for testing. Step 5. Switch to visual colorimetry: When instrument detection cannot be performed normally or there are doubts about the instrument detection results, switch to visual colorimetry as an auxiliary detection method; Step 6. Visual process monitoring: During the visual colorimetry process, arrange two or more testers to perform the colorimetry operation independently and record their respective colorimetry results; Step 7. Data processing and correction throughout the entire process: After the test is completed, record the test data and conduct a comprehensive analysis of the instrument test data and visual colorimetry results.

2. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: The sample collection tool in step 1 is: (1) Vertical sampling tools: retractable sampling tube and powder sampler; (2) Horizontal sampling tools: surface scraper and partition sampling shovel.

3. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: Sample collection process in step 1: S1.

1. In the vertical direction: Use a retractable sampling tube and powder sampler to collect samples from three different depths of the powder pile: the top, middle, and bottom. S1.

2. Horizontally: Use a surface scraper and a partitioned sampling shovel to collect calcium carbonate powder samples from the edge, center, and lower areas of the powder pile. Collect 3 to 5 parallel subsamples from each area. S1.

3. Sample reduction: Mix the collected sub-samples evenly and use the quartering method to reduce them to 500-600g as the samples to be tested.

4. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: The sample pretreatment process in step 2: S2.

1. Place the sample to be tested in a constant temperature drying oven at 105-110°C and dry for 2-4 hours; S2.

2. After drying, transfer the sample to be tested into a mortar and grind until it passes through a 200-300 mesh sieve; S2.

3. Place the ground sample in portions of 50 to 100 g into clean, dry, light-proof sealed containers and let them stand for 24 to 36 hours.

5. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: The colorimeter parameters in step 3 are set as follows: using D65 standard light source as the measurement light source, measuring aperture of 8 mm or 11 mm, and measuring times of 3 to 5 times.

6. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: Sample colorimetric detection process in step 3: S3.

1. Use a colorimeter as a colorimetric instrument. Before testing, calibrate the instrument using a standard white plate according to the instrument's operating manual. S3.

2. Align the calibrated instrument measurement aperture with the sample surface, evenly select 5 to 7 different locations on the sample surface for measurement, record the brightness, red-green axis, and yellow-blue axis values ​​at each location, and take the average value of the measurements at all locations as the instrument detection chromaticity result for the sample.

7. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: The situation where the measurement data fluctuates too much in step 4 is: the difference between two adjacent measurement values ​​exceeds the set threshold, the brightness value fluctuates by more than 2, and the red-green axis or yellow-blue axis value fluctuates by more than 1.

8. A calcium carbonate powder colorimetry method according to claim 1, characterized in that: Visual colorimetry in step 5: S5.

1. Prepare a set of standard calcium carbonate powder colorimetric cards; S5.

2. In a colorimetric box under standard lighting conditions, compare the sample to be tested with the colorimetric card; S5.

3. When observing, keep your eyes 20 to 30 cm away from the sample and the colorimetric card, with your line of sight perpendicular to the sample and the card surface. Observe and compare from angles of 30°, 60°, and 90° to obtain the final chromaticity grade.

9. A method for detecting colorimetry of calcium carbonate powder according to claim 1, characterized in that: In the step 6 of visual process monitoring, if the difference between the results of two inspectors exceeds one chromaticity level, an additional inspector is added to perform colorimetry, and the result of the majority of inspectors is taken as the standard. At the same time, the entire visual colorimetry process is video recorded for subsequent tracing and review.

10. A method for detecting colorimetry of calcium carbonate powder according to claim 1, characterized in that: The whole process of data processing and correction in step seven: S7.

1. After the test is completed, conduct a comprehensive analysis of the instrument test data and visual colorimetric results; S7.

2. When the results of the two test methods are similar, where the deviation between the brightness value of the instrument test and the brightness value of the standard sample corresponding to the visual colorimetry is within ±2, and the deviation between the red-green axis and the yellow-blue axis is within ±1, the instrument test result shall be used as the final color test result of the calcium carbonate powder; S7.

3. When the results differ significantly, re-examine the sample pretreatment process, the instrument status, and the visual colorimetry environment, analyze the causes of the discrepancies, and correct the problematic steps before retesting. S7.

4. Finally, organize and archive the original data, analysis results and correction records during the testing process.

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