Method for detecting exinite components in coal rock

Abstract

The invention provides a method for detecting exinite components in coal rock. The detection method comprises the following steps: S1, pretreating a coal sample to obtain coal briquettes; s2, the surface of the coal briquette is sequentially subjected to pre-grinding and three-stage grinding, and the ground coal briquette is obtained; s3, performing third-stage polishing on the polished coal briquette to obtain a coal rock polished section with a light reflecting effect; s4, exciting the coal rock polished section by using blue laser to enable exinite components in the coal rock polished section to present a fluorescent effect so as to obtain a coal rock maceral image; wherein the excitation time is longer than or equal to 10s; s5, identifying and measuring the exinite component according to the fluorescence characteristic and the morphological characteristic of the exinite component to obtain the volume content of the exinite component in the coal sample. The detection method disclosed by the invention has relatively high identification accuracy and accuracy on the exinite component in the coal, so that the accuracy and reliability of measuring the volume content of the exinite component are improved.

Description

Technical Field

[0001] This invention relates to the field of coal and rock microscopic component identification technology, and more specifically, to a method for detecting crustal components in coal and rock. Background Technology

[0002] The main organic microscopic components in coal include vitrinite, chalcanthite, and inertinite. Typically, vitrinite and inertinite are the major components in coal, present in high concentrations, while chalcanthite is present in lower concentrations. Therefore, while extensive research and experience have been developed for the accurate identification of vitrinite and inertinite in coal, accurate identification techniques for chalcanthite are less common. This results in the inability to accurately identify and measure the distribution characteristics and content of chalcanthite in coals rich in chalcanthite.

[0003] Currently, the main methods for determining the content of microscopic components in coal and petrology include heavy liquid centrifugation, property index method, automatic image analysis method, and point counting method. Heavy liquid centrifugation mainly involves centrifuging to separate microscopic components, weighing each density grade component, and using the content of different density grades to characterize the quantity of the corresponding microscopic components in the coal. However, this method is only applicable to components with large density differences, and the accuracy of the measurement results is low. The property index method mainly uses thermogravimetric analysis to determine the content of microscopic components based on the differences in volatile matter content. However, this method has low accuracy and a narrow range of applications. The automatic image analysis method uses the reflectance of different microscopic components to automatically identify and count the content of microscopic components through a computer. Since reflectance is not the only indicator for identifying coal and petrological components, the results of automatically measuring the content of coal and petrological components based on reflectance are relatively coarse. The point counting method uses a point-based statistical method to determine the content of microscopic components. This method is based on the differences in the optical properties of coal and petrological microscopic components, using a microscope to perform equal-step counting in both the horizontal and vertical directions. However, this method requires high-quality coal and petrological sections.

[0004] The "Classification of Microscopic Components in Bituminous Coal" (GB / T 15588-2013) and "Methods for Determination of Microscopic Components and Minerals in Coal" (GB / T 8899-2013) specify the characteristics and identification methods of the main microscopic components in coal. However, there are still some difficulties in accurately identifying and characterizing the crustal components in coal according to these national standards, specifically:

[0005] (1) The quality of coal and rock sections is extremely important for the identification of coal and rock components, including crustal components. Problems such as voids and scratches on the surface of coal and rock sections reduce the identification rate of microscopic components.

[0006] (2) The color of the shell component under oil-immersed reflected light is very similar to that of the metallographic adhesive, which causes interference in the identification process;

[0007] (3) The shell components have unique morphological features, but when identifying shell components under oil-immersed reflected light, the unique morphological features of the shell components are not fully utilized.

[0008] Therefore, there is an urgent need to develop a method that can accurately identify the crustal components in coal and measure their content. Summary of the Invention

[0009] The main objective of this invention is to provide a method for detecting crustal components in coal and rock, so as to solve the problem of poor accuracy in the identification and measurement of crustal components in existing technologies.

[0010] To achieve the above objectives, according to one aspect of the present invention, a method for detecting crustal components in coal and rock is provided. The method includes: step S1, pre-treating a coal sample to obtain a coal brick; step S2, sequentially pre-grinding and three-stage grinding of the surface of the coal brick to obtain a ground coal brick; step S3, performing three-stage polishing on the ground coal brick to obtain a reflective coal and rock slide; step S4, exciting the coal and rock slide with a blue laser to cause the crustal components in the slide to exhibit fluorescence, thereby obtaining a microscopic image of the coal and rock components; wherein the excitation time is ≥10s; and step S5, identifying and measuring the crustal components based on their fluorescence and morphological characteristics to obtain the volume content of the crustal components in the coal sample.

[0011] Further, in step S1 above, the coal sample is a coal mine rich in crustal components, and the volume content of crustal components in the coal mine is ≥5%; the particle size of the coal sample is -40mm, and the pretreatment process includes: crushing the coal sample to obtain crushed coal sample, and then subjecting the crushed coal sample to reduction and drying to obtain coal powder; mixing and molding the raw materials including metallographic adhesive powder, coal powder and metallographic adhesive curing agent to obtain coal bricks; wherein, the particle size of the crushed coal sample is -0.5mm, the mass ratio of metallographic adhesive powder to coal powder is 1:1~2:1, and the metallographic adhesive curing agent is a cold-curing epoxy resin.

[0012] Furthermore, in step S2 above, the surface of the coal brick is pre-polished using 320-400 grit water-resistant sandpaper for 10-60 seconds.

[0013] Furthermore, in step S2 above, the three-stage grinding includes coarse grinding, fine grinding, and precision grinding performed sequentially.

[0014] Further, coarse grinding is performed using 600-800 grit water-resistant sandpaper for 10-15 seconds; and / or, fine grinding is performed using 1200-1500 grit water-resistant sandpaper for 30-45 seconds; and / or, fine grinding is performed using 2000-3000 grit water-resistant sandpaper for 45-60 seconds.

[0015] Furthermore, in step S3 above, the three-stage polishing process includes coarse polishing, fine polishing, and precision polishing performed sequentially.

[0016] Furthermore, a first polishing slurry is used for rough polishing for 3-5 minutes; and / or a second polishing slurry is used for fine polishing for 6-9 minutes; and / or a third polishing slurry is used for finishing polishing for 9-15 minutes; the first, second, and third polishing slurries are each independently diamond water-based polishing slurries, the diamond particle size in the first polishing slurry is 2-4 μm, the diamond particle size in the second polishing slurry is 0.5-2 μm, and the diamond particle size in the third polishing slurry is 0.1-0.2 μm.

[0017] Furthermore, after each polishing, the polished sheet is cleaned with water for 5-8 minutes.

[0018] Further, in step S4 above, the coal-rock slide is placed under a fluorescence polarizing microscope, and a blue laser is used to excite the coal-rock slide, causing the crustal components in the coal-rock slide to exhibit a fluorescence effect. The fluorescence polarizing microscope is adjusted to obtain a clear image, and the coal-rock microscopic components are then measured. The measurement process includes: moving along a fixed direction with a step size of 0.2~0.4μm until the measurement points cover the entire coal-rock slide, and the number of measurement points is ≥500; and / or, the excitation time is 10~15s.

[0019] Furthermore, the chitinous component is selected from any one or more of the sporophyte, cuticle, cork body, resin body, bark body, and detrital chitin.

[0020] By applying the technical solution of this invention, this application, through the above-mentioned coal brick forming, grinding, and polishing, produces coal-rock polished sheets that are not only smooth in surface but also reflective, without problems such as voids and scratches, thereby greatly improving the quality of the coal-rock polished sheets. The color of the shell component under oil-immersion reflected light is extremely similar to the color of the metallographic adhesive in the coal-rock polished sheet, easily leading to significant errors in identification. This application utilizes the unique fluorescent properties of the shell component and, by controlling the exposure time (excitation time) of the coal-rock polished sheet under blue laser light, can significantly improve the color differentiation between the shell component and the metallographic adhesive, thereby improving the accuracy of identifying the shell component, inert component, and vitrinite component under oil-immersion reflected light. In summary, the "novel coal-rock polished sheet preparation method" proposed in this application can significantly improve the quality and yield of coal-rock polished sheets, solving the problems of high difficulty and low yield in coal-rock polished sheet preparation. Meanwhile, the "shell component identification method based on fluorescence characteristics and embedding morphology of shell components" proposed in this application improves the distinguishability of shell components from background metallographic colloids and the accuracy of shell component identification under oil-immersed reflected light during the identification process. Therefore, the method of this application has high accuracy and precision in identifying shell components in coal, thereby improving the accuracy and reliability of shell component volume content measurement. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 An optical photograph of a coal brick in Embodiment 1 of this application is shown;

[0023] Figure 2 An optical photograph of a coal and rock radiograph from Embodiment 1 of this application is shown;

[0024] Figure 3 An optical photograph of a coal brick in Comparative Example 1 of this application is shown;

[0025] Figure 4 An optical photograph of a coal and rock radiograph from Comparative Example 1 of this application is shown;

[0026] Figure 5 The image shows a coal petrographic microstructure of the crustal components in Example 1 of this application;

[0027] Figure 6 The image shows a coal petrographic microstructure of the crustal component in Comparative Example 2 of this application;

[0028] Figure 7 The image shows a coal petrographic microstructure of the crustal component in Comparative Example 3 of this application;

[0029] Figure 8 The diagram shows the morphological features of the chitinous component in Embodiment 1 of this application under oil-immersed reflected light.

[0030] The above figures include the following reference numerals:

[0031] 1. Sporophyte; 2. Cuticle; 3. Cork; 4. Resin body; 5. Bark body; 6. Detrital chlamydial. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] As analyzed in the background section of this application, the existing technology suffers from poor accuracy in identifying and measuring the crustal components of coal and rock. In order to solve the above problems, this application provides a method for detecting crustal components in coal and rock.

[0034] In a typical embodiment of this application, a method for detecting crustal components in coal is provided. The method includes: step S1, pre-treating a coal sample to obtain a coal brick; step S2, sequentially pre-grinding and three-stage grinding the surface of the coal brick to obtain a ground coal brick; step S3, performing three-stage polishing on the ground coal brick to obtain a coal-rock light sheet with reflective effect; step S4, exciting the coal-rock light sheet with a blue laser to make the crustal components in the coal-rock light sheet exhibit fluorescence, thereby obtaining a coal-rock microscopic component image; wherein the excitation time is ≥10s; step S5, identifying and measuring the crustal components based on their fluorescence and morphological characteristics to obtain the volume content of the crustal components in the coal sample.

[0035] This application, through the above-mentioned coal brick forming, grinding, and polishing, produces coal-rock smooth sheets with a smooth surface and reflective effect, free from voids and scratches, thus significantly improving the quality of the coal-rock smooth sheets. The color of the shell component under oil-immersion reflected light is extremely similar to the color of the metallographic adhesive in the coal-rock smooth sheet, easily leading to significant errors in identification. This application utilizes the unique fluorescence properties of the shell component and, by adjusting the exposure time (excitation time) of the coal-rock smooth sheet under blue laser light, can significantly improve the color differentiation between the shell component and the metallographic adhesive, thereby improving the accuracy of identifying the shell component, inert component, and vitrinite component under oil-immersion reflected light. In summary, the "novel coal-rock smooth sheet preparation method" proposed in this application can significantly improve the quality and yield of coal-rock smooth sheets, solving the problems of high preparation difficulty and low yield. Simultaneously, the "shell component identification method based on the fluorescence characteristics and embedding morphology features of the shell component" proposed in this application improves the differentiation between the shell component and the background metallographic adhesive during the identification process and the accuracy of shell component identification under oil-immersion reflected light. Therefore… The method of this application has high accuracy and precision in identifying shell components in coal, thereby improving the accuracy and reliability of measuring the volume content of shell components.

[0036] In one embodiment of this application, in step S1 above, the coal sample is a coal mine rich in crustal components, and the volume content of crustal components in the coal mine is ≥5%, preferably 5~15%; the particle size of the coal sample is -40mm, and the pretreatment process includes: crushing the coal sample to obtain crushed coal sample, and sequentially reducing and drying the crushed coal sample to obtain coal powder; sequentially mixing and molding the raw materials including metallographic adhesive powder, coal powder and metallographic adhesive curing agent to obtain coal bricks; wherein, the particle size of the crushed coal sample is -0.5mm, the mass ratio of metallographic adhesive powder to coal powder is 1:1~2:1, and the metallographic adhesive curing agent is a cold-curing epoxy resin, preferably a G90400 type metallographic adhesive curing agent.

[0037] The coal samples described above are rich in crustal components, and the method described above helps to accurately measure the volume content of these components. A preferred mass ratio of metallographic adhesive powder to coal powder within the above-mentioned range helps to improve the hardness of the coal bricks, reduce voids and surface scratches, thus benefiting subsequent grinding and polishing. A preferred type of metallographic adhesive curing agent within the above-mentioned range helps to improve the curing speed and the structural stability of the coal bricks.

[0038] A particle size of -40mm means that the particle diameter is ≤40mm.

[0039] Coal powder is prepared by using a reducing device and can be prepared in accordance with the "Preparation Method of Coal Samples" (GB / T 474-2008).

[0040] After mixing metallographic adhesive powder and coal powder, a metallographic adhesive curing agent is added, and the mixture is slowly stirred until it reaches a fluid state. The mixture is then poured into a mold to form the final product. During the stirring and mixing process, it is done slowly in the same direction. This helps the crushed coal sample and the metallographic adhesive to mix thoroughly, reducing the formation of air bubbles and thus reducing voids and cracks on the surface of the coal brick, thereby improving the quality of the coal rock sheet.

[0041] Make sure the coal bricks are completely dry before grinding. If the coal bricks are not completely dry and hardened before grinding, it may be impossible to grind them to a smooth surface or large holes may appear.

[0042] In one embodiment of this application, in step S2 above, the surface of the coal brick is pre-polished using 320-400 grit water-resistant sandpaper for 10-60 seconds.

[0043] Pre-grinding the surface of the coal bricks is preferred. Controlling the pre-grinding time within the above range helps to remove excess glue from the uneven surface of the coal bricks.

[0044] In order to further improve the grinding effect and obtain a smooth surface without obvious protrusions and scratches, in one embodiment of this application, the three-stage grinding in step S2 above includes coarse grinding, fine grinding and fine grinding performed in sequence.

[0045] In one embodiment of this application, coarse grinding is performed using 600-800 grit water-resistant sandpaper for 10-15 seconds; and / or, fine grinding is performed using 1200-1500 grit water-resistant sandpaper for 30-45 seconds; and / or, fine grinding is performed using 2000-3000 grit water-resistant sandpaper for 45-60 seconds.

[0046] Using water-resistant sandpaper of the aforementioned grit for three-stage grinding is preferred, as this helps improve the flatness and smoothness of the coal brick surface after grinding. Using water-resistant sandpaper of the aforementioned grit for coarse grinding, and controlling the grinding time within the aforementioned range, helps remove larger defects on the coal brick surface, laying a good foundation for subsequent fine and finishing grinding. Using water-resistant sandpaper of the aforementioned grit for fine grinding, and controlling the grinding time within the aforementioned range, helps further improve the flatness of the coal brick surface and reduces small defects that were not completely smoothed during coarse grinding. Using water-resistant sandpaper of the aforementioned grit for finishing grinding, and controlling the finishing grinding time within the aforementioned range, helps achieve a high degree of surface smoothness and flatness, resulting in a smooth surface of the coal brick after grinding, free of obvious protrusions and scratches, which is beneficial for obtaining clear coal and petrographic microscopic images.

[0047] In order to further improve the polishing effect and obtain a smooth and reflective coal and rock polished sheet, in one embodiment of this application, the three-stage polishing process in step S3 above includes coarse polishing, fine polishing and precision polishing performed in sequence.

[0048] In one embodiment of this application, a first polishing slurry is used for coarse polishing for 3-5 minutes; and / or a second polishing slurry is used for fine polishing for 6-9 minutes; and / or a third polishing slurry is used for finishing polishing for 9-15 minutes; the first, second, and third polishing slurries are each independently diamond water-based polishing slurries, the diamond particle size in the first polishing slurry is 2-4 μm, the diamond particle size in the second polishing slurry is 0.5-2 μm, and the diamond particle size in the third polishing slurry is 0.1-0.2 μm.

[0049] Using the aforementioned polishing fluid for three-stage polishing is preferred, as it helps improve the surface quality of the coal and rock sheet. Using the first polishing fluid with the aforementioned particle size for coarse polishing, and controlling the coarse polishing time within the aforementioned range, helps reduce scratches on the coal brick surface after grinding and improves flatness. Using the aforementioned second polishing fluid for fine polishing, and controlling the fine polishing time within the aforementioned range, helps further improve the flatness and reflectivity of the sheet surface. Using the aforementioned third polishing fluid for finishing polishing, and controlling the finishing polishing time within the aforementioned range, helps to make the surface of the coal and rock sheet smooth and achieve a good reflectivity, thereby improving the fluorescence effect of the coal and rock sheet.

[0050] The preferred first polishing fluid is S01-0120D3 type diamond water-based polishing fluid, the preferred second polishing fluid is S01-0120D1 type diamond water-based polishing fluid, and the preferred third polishing fluid is S01-0120D0.1 type diamond water-based polishing fluid.

[0051] In one embodiment of this application, the polished sheet is cleaned with water after each polishing process, and the cleaning time is 5 to 8 minutes.

[0052] The polishing cloth is used to perform three-stage polishing on the ground coal bricks. Because the particle size of the third polishing liquid is relatively fine and the contact time with the ground coal bricks is relatively long, the polishing liquid may adhere and accumulate on the surface of the coal bricks. Therefore, the surface of the polishing cloth is cleaned and mixed every 3 to 5 minutes before continuing the fine polishing operation. After each polishing, the polished sheet is placed in an ultrasonic cleaning instrument for water cleaning, which helps to remove excess polishing liquid and reduce the adhesion and accumulation of polishing liquid on the surface of the coal bricks.

[0053] In one embodiment of this application, in step S4 above, the coal-rock slide is placed under a fluorescence polarizing microscope, and a blue laser is used to excite the coal-rock slide, causing the shell components in the coal-rock slide to exhibit a fluorescence effect. The fluorescence polarizing microscope is adjusted to obtain a clear image, and the coal-rock microscopic components are then measured. The measurement process includes: moving along a fixed direction according to a step size until the measurement points cover the coal-rock slide, with a step size of 0.2~0.4μm and the number of measurement points ≥500, preferably 500~550; and / or, the excitation time is 10~15s.

[0054] Using an imaging system including a fluorescence polarizing microscope, refer to the "Methods for Microanalysis and Mineral Determination of Coal" (GB / T 8899-1998). Adjust the focus, correct the objective center, and adjust the light source, aperture, and field of view of the fluorescence polarizing microscope to ensure moderate brightness, uniform light, and clear imaging, thereby obtaining a clear image of the microanalysis of coal and petrology.

[0055] The measurement process begins at one end of the coal petrographic microscopic image. The types of microscopic components under the crosshair focus of the microscope are identified and recorded in the corresponding counting key. The microscope then moves one step in a fixed direction according to a predetermined step size. Points encountering gelatinous structures, cellular cavities, voids, fissures in fibrous components, or unidentifiable microparticles are considered invalid and not counted; the process continues. When a row of measurements is completed, the microscope moves to the next row and continues measuring until the entire coal petrographic section is covered. The volumetric content of the crustal component is expressed as a percentage of the total number of valid points.

[0056] Using blue laser to excite the coal and rock light section and controlling the excitation time within the above range helps the shell components to fully exert their fluorescence properties, further improving the color differentiation between the shell components and the metallographic adhesive, thereby improving the accuracy of shell component identification.

[0057] By adopting the above-described measurement process and controlling the step size and the number of measurement points within the above-described range, it is helpful to improve the accuracy of the determination of the volume content of chitin components.

[0058] In one embodiment of this application, the chitinous component is selected from any one or more of sporophyte, cuticle, cork body, resin body, bark body, and detrital chitin.

[0059] In addition to using the fluorescence properties of crustal components for microscopic identification, the classification criteria for coal and petrographic components can be used to determine the components based on the unique morphological characteristics of crustal components under oil-immersed reflected light. This helps to further improve the accuracy of crustal component volume content determination.

[0060] The morphological characteristics of sporophytes are as follows: they are mostly closed, flattened, elongated rings or worm-like structures, occurring mostly as single individuals in coal, and sometimes sporophyte masses can be seen. The morphological characteristics of cutinites are as follows: they are mostly long, ribbon-like structures with smooth outer edges, serrated inner edges, and pointed ends. The morphological characteristics of cork granules are as follows: they mostly exhibit a brick-like or tile-like structure. The morphological characteristics of resin granules are as follows: they are round, oval, and irregular in shape, scattered in coal or filling the cell cavities of plant tissues. The morphological characteristics of bark granules are as follows: they are mostly flattened rectangles with distinct cellular morphology. The morphological characteristics of detrital crusts are as follows: they are mostly angular or irregular in shape, often occurring in groups.

[0061] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0062] Example 1

[0063] The coal samples were sourced from a crust-rich coal mine in the Chahaquan area of ​​Xinjiang.

[0064] A coal sample with a particle size of -40mm was crushed to -0.5mm using a small crusher to obtain a crushed coal sample. The crushed coal sample was then subjected to reduction and drying to obtain coal powder. 2g of metallographic adhesive powder and coal powder (mass ratio 1:1) were mixed, and then 1.2g of metallographic adhesive curing agent (G90400 type metallographic adhesive curing agent) was added. The mixture was slowly stirred until it reached a fluid state, poured into a mold, and shaped to obtain coal bricks. During the mixing and stirring process, the process was carried out slowly in the same direction.

[0065] The coal bricks were pre-polished and then polished in three stages using a fully automatic metallographic polishing machine. The specific process was as follows: the surface of the coal bricks was pre-polished for 30 seconds using 320-grit water-resistant sandpaper, followed by three-stage polishing. The three-stage polishing process involved coarse polishing with 600-grit water-resistant sandpaper for 15 seconds, fine polishing with 1200-grit water-resistant sandpaper for 30 seconds, and fine polishing with 2000-grit water-resistant sandpaper for 60 seconds, until the surface of the coal bricks was smooth and free of obvious protrusions and scratches, resulting in polished coal bricks.

[0066] A fully automatic metallographic polishing machine was used to perform three-stage polishing on the ground coal bricks using polishing cloth. The specific process was as follows: coarse polishing for 3 minutes was performed using the first polishing fluid (S01-0120D3 type diamond water-based polishing fluid, diamond particle size of 3μm); fine polishing for 6 minutes was performed using the second polishing fluid (S01-0120D1 type diamond water-based polishing fluid, diamond particle size of 1μm); and final polishing for 9 minutes was performed using the third polishing fluid (S01-0120D0.1 type diamond water-based polishing fluid, diamond particle size of 0.1μm). This resulted in smooth coal and rock polished sheets with a reflective effect. During the final polishing process, the polishing cloth was cleaned every 3 minutes before continuing the final polishing. After each polishing, the polished sheets were placed in an ultrasonic cleaning instrument and rinsed with water for 6 minutes.

[0067] The coal-rock section was placed under a fluorescence polarizing microscope and excited with a blue laser for 10 seconds to induce fluorescence in the crustal components. The microscope was then adjusted to obtain a clear image of the coal-rock microstructures for measurement. The measurement process began from one end of the microstructure image, identifying the types of microstructures under the crosshair focus and recording them in the corresponding counter. The microscope was then moved one step at a time in a fixed direction, incrementing by 0.3 μm. Points encountering gel-like structures, cellular cavities, voids, fissures, or unidentifiable microparticles were considered invalid and not counted; the process continued. When a row of measurements was completed, the microscope moved to the next row and continued until the entire coal-rock section was covered with measurement points, totaling 500 points. The volume content of the crustal components was expressed as a percentage of the total number of valid points.

[0068] The shell-like components exhibit a distinct yellow-green or bright yellow color under blue light excitation. Each sub-component possesses its own morphological characteristics: sporophytes appear as closed, flattened rings or worm-like structures; cuticles are elongated bands with smooth outer edges and serrated inner edges, ending in sharp corners; cork bodies are stacked brick-like or tile-like structures; resin bodies are scattered in round, elliptical, and irregular shapes; bark bodies exhibit uneven coloring; and detrital shell-like components have a particle size less than 3 μm and appear in clusters. The shell-like components were identified and measured based on their fluorescence characteristics and morphological characteristics under oil-immersed reflected light. The identification results showed that the morphological characteristics of each sub-component included sporophytes, cuticles, cork bodies, resin bodies, bark bodies, and detrital shell-like components. The volumetric content of the shell-like components in the coal sample was measured using both fluorescence and morphological characteristics.

[0069] Example 2

[0070] The difference from Example 1 is that the coal sample with a particle size of -40mm was crushed to -0.5mm using a small crusher to obtain the crushed coal sample. The crushed coal sample was then subjected to reduction and drying to obtain coal powder. 3g of metallographic adhesive powder and coal powder (mass ratio of 2:1) were mixed, and then 1.6g of metallographic adhesive curing agent (G90400 type metallographic adhesive curing agent) was added. The mixture was slowly stirred until it reached a fluid state, poured into a mold, and shaped to obtain coal bricks. During the mixing and stirring process, the process was carried out slowly in the same direction.

[0071] The coal bricks were pre-polished and then polished in three stages using a fully automatic metallographic polishing machine. The specific process was as follows: the surface of the coal bricks was pre-polished for 40 seconds using 400-grit water-resistant sandpaper, followed by three-stage polishing. The three-stage polishing process involved coarse polishing with 800-grit water-resistant sandpaper for 12 seconds, fine polishing with 1300-grit water-resistant sandpaper for 40 seconds, and fine polishing with 2500-grit water-resistant sandpaper for 45 seconds, until the surface of the coal bricks was smooth and free of obvious protrusions and scratches, resulting in polished coal bricks.

[0072] A fully automatic metallographic polishing machine was used to perform three-stage polishing on the ground coal bricks using polishing cloth. The specific process was as follows: coarse polishing for 3 minutes was performed using the first polishing fluid (S01-0120D3 type diamond water-based polishing fluid, diamond particle size of 3μm); fine polishing for 6 minutes was performed using the second polishing fluid (S01-0120D1 type diamond water-based polishing fluid, diamond particle size of 1μm); and final polishing for 9 minutes was performed using the third polishing fluid (S01-0120D0.1 type diamond water-based polishing fluid, diamond particle size of 0.1μm). This resulted in smooth coal and rock polished sheets with a reflective effect. During the final polishing process, the polishing cloth was cleaned every 3 minutes before continuing the final polishing. After each polishing, the polished sheets were placed in an ultrasonic cleaning instrument and rinsed with water for 8 minutes.

[0073] The coal rock section was placed under a fluorescence polarizing microscope and excited with a blue laser for 10 seconds to induce fluorescence in the crustal components. The microscope was then adjusted to obtain a clear image of the coal rock microstructure, which was then measured. The measurement process involved moving the microscope in a fixed direction with a step size of 3 μm until the measurement points covered the entire coal rock section. A total of 550 measurement points were used to obtain the volume content of the crustal components in the coal sample.

[0074] Example 3

[0075] The difference from Example 1 is that a fully automatic metallographic polishing machine is used to pre-polish and then perform three-stage polishing on the coal bricks. The specific process is as follows: the surface of the coal bricks is pre-polished for 60 seconds using 400-grit water-resistant sandpaper, followed by three-stage polishing. The three-stage polishing process involves coarse polishing for 10 seconds using 800-grit water-resistant sandpaper, fine polishing for 45 seconds using 1500-grit water-resistant sandpaper, and fine polishing for 60 seconds using 3000-grit water-resistant sandpaper, until the surface of the coal bricks is smooth and free of obvious protrusions and scratches. The polished coal bricks are obtained, and the volume content of the shell components in the coal sample is finally obtained.

[0076] Example 4

[0077] The difference from Example 1 is that a fully automatic metallographic polishing machine was used to pre-polish and then perform three-stage polishing on the coal bricks. The specific process is as follows: the surface of the coal bricks was pre-polished for 2 minutes using 320-grit water-resistant sandpaper, followed by three-stage polishing. The three-stage polishing process involved coarse grinding for 60 seconds using 600-grit water-resistant sandpaper, fine grinding for 30 seconds using 1200-grit water-resistant sandpaper, and fine grinding for 15 seconds using 2000-grit water-resistant sandpaper, until the surface of the coal bricks was smooth and free of obvious protrusions and scratches. The polished coal bricks were obtained, and the volume content of the shell components in the coal sample was finally obtained.

[0078] Example 5

[0079] The difference from Example 1 is that a fully automatic metallographic polishing machine was used, and a polishing cloth was used to perform three-stage polishing on the ground coal bricks. The specific process is as follows: coarse polishing for 5 minutes with the first polishing liquid (S01-0120D3 type diamond water-based polishing liquid), fine polishing for 9 minutes with the second polishing liquid (S01-0120D1 type diamond water-based polishing liquid), and fine polishing for 15 minutes with the third polishing liquid (S01-0120D0.1 type diamond water-based polishing liquid), resulting in a smooth coal rock polished sheet with a reflective effect. During the fine polishing process, the polishing cloth was cleaned every 3 minutes before continuing fine polishing. After each polishing, the polished sheet was placed in an ultrasonic cleaning instrument and rinsed with water for 8 minutes.

[0080] Example 6

[0081] The difference from Example 1 is that a fully automatic metallographic polishing machine was used, and polishing cloth was used to perform three-stage polishing on the ground coal bricks. The specific process is as follows: coarse polishing for 7 minutes with the first polishing liquid (S01-0120D3 type diamond water-based polishing liquid), fine polishing for 5 minutes with the second polishing liquid (S01-0120D2 type diamond water-based polishing liquid), and fine polishing for 6 minutes with the third polishing liquid (S01-0120D0.1 type diamond water-based polishing liquid), resulting in a smooth coal rock polished sheet with a reflective effect. During the fine polishing process, no cleaning was performed; only after each polishing, the polished sheet was placed in an ultrasonic cleaning instrument for water cleaning for 8 minutes.

[0082] Example 7

[0083] The difference from Example 1 is that a blue laser coal rock sheet was used for excitation for 15 seconds to finally obtain the volume content of the crustal component in the coal sample.

[0084] Example 8

[0085] The difference from Example 1 is that the coal sample with a particle size of -40mm was crushed to -0.5mm using a small crusher to obtain the crushed coal sample. The crushed coal sample was then subjected to fractionation and drying to obtain coal powder. 2g of metallographic adhesive powder and coal powder (mass ratio 1:1) were mixed, and 1.2g of metallographic adhesive curing agent (G90400 type metallographic adhesive curing agent) was added. The mixture was slowly stirred until it reached a fluid state, poured into a mold, and shaped to obtain coal bricks. During the mixing and stirring process, the mixing and stirring were carried out rapidly in different directions to ultimately obtain the volume content of the shell component in the coal sample.

[0086] Comparative Example 1

[0087] The difference from Example 1 is that the coal sample with a particle size of -40mm was crushed to -0.5mm using a small crusher to obtain the crushed coal sample. The crushed coal sample was then subjected to reduction and drying to obtain coal powder. 4g of metallographic adhesive powder and coal powder (mass ratio of 1:1) were mixed, and 1.6g of metallographic adhesive curing agent (G90400 type metallographic adhesive curing agent) was added. The mixture was stirred until it reached a fluid state, poured into a mold, and shaped to obtain coal bricks.

[0088] The coal bricks were pre-polished and then polished in three stages using a fully automatic metallographic polishing machine. The specific process was as follows: the surface of the coal bricks was pre-polished using 320-grit water-resistant sandpaper; then, three stages of polishing were performed, in which W10, W5, and W3.5 white corundum powder mixed with water were successively ground on a frosted glass plate, and the polished sheet was coarsely ground, finely ground, and finely ground until the surface of the coal bricks was smooth and free of obvious protrusions and scratches, thus obtaining the polished coal bricks.

[0089] A fully automatic metallographic polishing machine was used, along with gold velvet polishing cloth, to perform fine and high-precision polishing on the ground coal bricks. The specific process was as follows: fine polishing was performed using gold velvet polishing cloth and alumina powder slurry as the polishing material; high-precision polishing was then performed using finer silk polishing cloth and acidic silica sol as the polishing material, resulting in smooth coal and rock polished sheets with a reflective effect. After polishing, the polished sheets were placed in an ultrasonic cleaning instrument and rinsed with water for 6 minutes.

[0090] The coal rock section was placed under a fluorescence polarizing microscope, and the microscope was adjusted to obtain a clear image. After obtaining the microscopic composition image of the coal rock, measurements were performed. During the measurement process, the microscope was moved in a fixed direction with a step size of 0.3 μm until the measurement points covered the entire coal rock section. A total of 550 measurement points were used, and the volume content of the crustal component in the coal sample was finally measured.

[0091] Comparative Example 2

[0092] The difference from Example 1 is that a blue laser coal rock sheet was used for excitation for 5.5 seconds to finally obtain the volume content of the crustal component in the coal sample.

[0093] Comparative Example 3

[0094] The difference from Example 1 is that a blue laser coal rock sheet was used for excitation for 1.5s to finally obtain the volume content of the crustal component in the coal sample.

[0095] Test method:

[0096] The pass rate of coal and rock polished sheets = the number of qualified coal and rock polished sheets / the total number of coal and rock polished sheets prepared; where qualified coal and rock polished sheets refer to sheets with smooth surfaces and reflective properties. (The total number of coal and rock polished sheets prepared is based on 50 sheets).

[0097]

[0098] The test results are shown in Table 1.

[0099] Table 1

[0100]

[0101] in, Figure 1 These are optical photographs of the coal bricks in Example 1, from... Figure 1 As can be seen from the example, the coal bricks in Example 1 have a smooth surface and no voids.

[0102] Figure 2 These are optical photographs of the coal and rock radiographs from Example 1. Figure 2 As can be seen from the image, the surface of the coal and rock sheet in Example 1 is smooth and bright.

[0103] Figure 3This is an optical photograph of the coal brick in Example 1, from... Figure 3 As can be seen from the comparison, obvious voids appeared on the surface of the coal bricks in Comparative Example 1.

[0104] Figure 4 This is an optical photograph of the coal and rock light section in Comparative Example 1, from... Figure 4 As can be seen from the comparison, obvious scratches appear on the surface of the coal and rock slice in Comparative Example 1.

[0105] Figure 5 These are petrographic images of the crustal components in Example 1, from... Figure 5 As can be seen from Example 1, when the blue laser excitation time is 10s, the fluorescence characteristics of the shell component can be fully utilized, making it appear obvious yellow; the vitrinite does not reflect the blue laser and appears black; the metallographic colloid appears green and transparent, with clear coal particle boundaries; under these conditions, the color difference between the shell component and the metallographic colloid is significantly improved, thereby effectively improving the accuracy of shell component identification.

[0106] Figure 6 These are microscopic images of the coal petrographic components in Comparative Example 2, from... Figure 6 As can be seen from Comparative Example 2, the fluorescence characteristics of the shell-like components were not fully expressed when the blue laser excitation time was 5.5 s, resulting in a darker yellow color. The vitrinite did not react to the blue laser and appeared black. Due to the short exposure time, the overall brightness of the image was dark, and the boundaries of the coal particles were blurred, which is not conducive to the efficient identification of the shell-like components.

[0107] Figure 7 These are microscopic images of the coal petrographic components in Comparative Example 3, from... Figure 7 As can be seen from Comparative Example 3, when the blue laser excitation time is 1.5s, the fluorescence characteristics of the shell component are not fully expressed due to the short excitation time, making it appear as a very dark yellow; the vitrinite does not react to the blue laser and appears as black; due to the short exposure time, the overall brightness of the image is too dark, the metallographic colloid appears as a dark green, and the boundary between the coal particles and the colloid is blurred, making it impossible to identify the components.

[0108] Figure 8 This is a morphological feature image of the chitinous component in Example 1 under oil-immersed reflected light. Figure 8 As can be seen from the text, the chitinous component in Example 1 includes sporophyte 1, such as... Figure 8 As shown in a; keratinocyte 2, as... Figure 8 As shown in b; cork body 3, as Figure 8 As shown in c; resin body 4, as... Figure 8 As shown in d; bark body 5, as Figure 8 As shown in e; clastic chitinous body 6, as... Figure 8 As shown in f.

[0109] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0110] This application, through the above-mentioned coal brick forming, grinding, and polishing, produces coal-rock smooth sheets with a smooth surface and reflective effect, free from voids and scratches, thus significantly improving the quality of the coal-rock smooth sheets. The color of the shell component under oil-immersion reflected light is extremely similar to the color of the metallographic adhesive in the coal-rock smooth sheet, easily leading to significant errors in identification. This application utilizes the unique fluorescence properties of the shell component and, by adjusting the exposure time (excitation time) of the coal-rock smooth sheet under blue laser light, can significantly improve the color differentiation between the shell component and the metallographic adhesive, thereby improving the accuracy of identifying the shell component, inert component, and vitrinite component under oil-immersion reflected light. In summary, the "novel coal-rock smooth sheet preparation method" proposed in this application can significantly improve the quality and yield of coal-rock smooth sheets, solving the problems of high preparation difficulty and low yield. Simultaneously, the "shell component identification method based on the fluorescence characteristics and embedding morphology features of the shell component" proposed in this application improves the differentiation between the shell component and the background metallographic adhesive during the identification process and the accuracy of shell component identification under oil-immersion reflected light. Therefore… The method of this application has high accuracy and precision in identifying shell components in coal, thereby improving the accuracy and reliability of measuring the volume content of shell components.

[0111] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting crustal components in coal and rock, characterized in that, The detection method includes: Step S1: Pre-treat the coal sample to obtain coal bricks; Step S2: The surface of the coal brick is pre-polished and then polished in three stages to obtain polished coal bricks. Step S3: The polished coal brick is subjected to three-stage polishing to obtain a coal rock polishing sheet with reflective effect; Step S4: Excite the coal and rock light section with a blue laser to make the crustal components in the coal and rock light section exhibit fluorescence, thereby obtaining a microscopic image of the coal and rock components; wherein, the excitation time is ≥10s; Step S5: Identify and measure the shell components based on their fluorescence and morphological characteristics to obtain the volume content of the shell components in the coal sample.

2. The detection method according to claim 1, characterized in that, In step S1, the coal sample is a coal mine rich in crustal components, and the volume content of the crustal components in the coal mine is ≥5%; The coal sample has a particle size of -40mm. The pretreatment process includes: crushing the coal sample to obtain a crushed coal sample; sequentially reducing and drying the crushed coal sample to obtain coal powder; sequentially mixing and molding raw materials including metallographic adhesive powder, the coal powder, and metallographic adhesive curing agent to obtain the coal brick; wherein, the particle size of the crushed coal sample is -0.5mm, the mass ratio of the metallographic adhesive powder to the coal powder is 1:1 to 2:1, and the metallographic adhesive curing agent is a cold-curing epoxy resin.

3. The detection method according to claim 1 or 2, characterized in that, In step S2, the surface of the coal brick is pre-polished using 320-400 grit water-resistant sandpaper for 10-60 seconds.

4. The detection method according to any one of claims 1 to 3, characterized in that, In step S2, the three-stage polishing includes coarse polishing, fine polishing, and precision polishing performed sequentially.

5. The detection method according to claim 4, characterized in that, The coarse grinding is performed using 600-800 grit water-resistant sandpaper, and the coarse grinding time is 10-15 seconds. And / or, the fine grinding is performed using 1200~1500 grit water-resistant sandpaper, and the fine grinding time is 30~45 seconds; And / or, the fine grinding is performed using 2000-3000 grit water-resistant sandpaper, and the fine grinding time is 45-60 seconds.

6. The detection method according to any one of claims 1 to 5, characterized in that, In step S3, the three-stage polishing process includes coarse polishing, fine polishing, and precision polishing performed sequentially.

7. The detection method according to claim 6, characterized in that, The coarse polishing is performed using a first polishing liquid for 3-5 minutes. And / or, the fine polishing is performed using a second polishing liquid for a time of 6-9 minutes; And / or, the fine polishing is performed using a third polishing solution for a time of 9-15 minutes; The first polishing slurry, the second polishing slurry, and the third polishing slurry are each independently diamond water-based polishing slurries. The diamond particle size in the first polishing slurry is 2~4μm, the diamond particle size in the second polishing slurry is 0.5~2μm, and the diamond particle size in the third polishing slurry is 0.1~0.2μm.

8. The detection method according to claim 6, characterized in that, After each polishing, the polished sheet is cleaned with water for 5-8 minutes.

9. The detection method according to any one of claims 1 to 8, characterized in that, In step S4, the coal and rock slide is placed under a fluorescence polarizing microscope, and a blue laser is used to excite the coal and rock slide, causing the crustal components in the coal and rock slide to exhibit a fluorescence effect. The fluorescence polarizing microscope is adjusted to obtain a clear image, and the coal and rock microscopic components are then measured. The measurement process includes moving along a fixed direction according to a step size until the measurement points cover the entire coal and rock slide. The step size is 0.2~0.4μm, and the number of measurement points is ≥500. And / or, the excitation time is 10~15s.

10. The detection method according to any one of claims 1 to 9, characterized in that, The chitinous component is selected from any one or more of the sporophyte, cuticle, cork body, resin body, bark body, and detrital chitin.

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