Integrated manufacturing technological process for polished thin sheet

Abstract

The invention discloses a polished thin sheet integrated manufacturing technological process, and belongs to the technical field of rock and ore identification sample preparation, and the polished thin sheet integrated manufacturing technological process comprises the following steps: S1, sample selection and cutting: selecting a representative rock or ore specimen according to a research purpose, and cutting by adopting a diamond saw blade to obtain a blank with the size of not less than 25mm * 30mm and the thickness of 2-3mm, the cutting surface comprises key minerals or structures to be researched; s2, flat grinding and sheet bonding are conducted, specifically, rough grinding, fine grinding and accurate grinding are conducted on one section of the blank obtained in the step 1 in sequence, and the flatness of the section meets the sheet bonding requirement; pasting the flattened section on a clean glass slide by adopting epoxy resin; and S3, accurate grinding to the standard sheet thickness, specifically, a sheet grinding machine is used for grinding the non-sheet-bonded face of the blank, and the pressure is kept uniform in the grinding process. The method has the technical effects that the information fidelity is high, the research efficiency is high, the sample utilization rate is high, and key cause information can be revealed.

Description

Technical Field

[0001] This invention belongs to the field of rock and mineral identification and sample preparation technology, and in particular relates to an integrated process for fabricating thin optical sections. Background Technology

[0002] Rock and mineral identification is a core foundation of research in geology, mineral deposit geology, petrology and other disciplines. It involves observing the optical, physical and chemical properties of minerals under a microscope to determine the mineral type, content, structure and formation sequence. The quality of sample preparation directly determines the accuracy and depth of the identification results.

[0003] Since the introduction of thin section techniques into geology in the mid-19th century, standard rock thin sections with a thickness of 0.03 mm have become crucial for studying the optical properties of transparent rock-forming minerals (such as feldspar, quartz, and mica) under transmitted light. However, for opaque minerals (such as pyrite, chalcopyrite, and magnetite), optical sections (with mirror-polished surfaces) are used to observe their reflectivity, color, and other characteristics under reflected light. However, rocks and ores in nature are often complex aggregates of both transparent and opaque minerals, and traditional methods of separating and preparing samples (preparing thin sections and optical sections separately) have significant drawbacks. Information loss: The inability to accurately correspond the same microscopic region of different samples in space leads to the loss of key genetic information such as mineral association, metasomatic structure, and mineralization generation sequence; Inefficiency: Researchers need to switch between two samples repeatedly to find the corresponding region, which prolongs the research cycle; Sample waste: For precious samples such as meteorites, lunar rocks, and deep-sea drill cores, separation and sample preparation cannot maximize the utilization of sample value.

[0004] To address the aforementioned issues, the integrated thin-section optical section technique emerged. This technique integrates the transmitted light observation function of the thin section with the reflected light observation function of the optical section onto the same sample, enabling in-situ and simultaneous research on mineral associated assemblages, and greatly promoting the development of genetic mineralogy and ore deposit geology. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an integrated fabrication process for optical thin sections, which has the advantages of high information fidelity, high research efficiency, high sample utilization, and the ability to reveal key genetic information. It solves the problems of loss of sample preparation information, low efficiency of sample switching for observation, high consumption of precious samples, and difficulty in clearly presenting key mineral structures to interpret the diagenetic and mineralization process in the prior art.

[0006] This invention is implemented as follows: a process for integrally fabricating a thin optical sheet, comprising the following steps: S1. Sample selection and cutting: Select representative rock or mineral specimens according to the research purpose, and cut them with diamond saw blades to obtain blanks with a size of not less than 25mm×30mm and a thickness of 2-3mm, and the cut surface contains the key minerals or structures to be studied. S2. Grinding and bonding: The cut surface of the blank obtained in step 1 is subjected to coarse grinding, fine grinding and fine grinding in sequence to make the flatness of the cut surface meet the requirements for gluing; the flattened cut surface is glued onto a clean glass slide using epoxy resin, wherein the epoxy resin is a two-component resin that solidifies at room temperature or a solid resin that is melted by heating. S3. Grind to standard sheet thickness: The unattached side of the blank is ground using a thin-plate grinding machine. During the grinding process, the pressure is kept uniform, and the interference color is observed under a microscope at preset intervals until the blank thickness reaches the standard thin-plate thickness of 0.03 mm. S4. Cover sheet and initial curing: Clean and dry the blank area that has reached the standard thickness in step 3, cover and seal the area with resin and cover glass, and let it stand until the resin has initially cured. S5, Area Thickening: Use corrosion-resistant, high-strength tape or special coating to completely cover and protect the area that has been covered in step 4. For the area of ​​the blank that has not been covered and needs to be made into a smooth sheet, use special epoxy resin to build up and thicken it to form a solid base, and let it stand until the epoxy resin is completely cured. S6. Grinding and Polishing: For the thickened area in step 5, use diamond grinding discs with 600 mesh, 1000 mesh, and 2000 mesh grit in sequence to grind it so that the surface of the thickened area is close to the same plane as the surface of the cover plate area. Then switch to the polishing machine and use diamond spray, alumina or silica polishing liquid with a woolen polishing disc to polish it until the surface of the thickened area forms a mirror surface without visible scratches. S7. Cleaning and Inspection: The sample is thoroughly cleaned with deionized water or a special cleaning agent to remove residual abrasive and polishing agent from the grinding and polishing process. The optical quality of the cover plate area (interference color, transparency, no cracks) is checked under a transmitted light microscope, and the mirror quality of the polished area (no scratches, uniform reflection) is checked under a reflected light microscope. If both meet the standards, the optical sheet fabrication is complete.

[0007] As a preferred embodiment of the present invention, in step S1, when cutting the blank, the rotation speed of the diamond saw blade is controlled to be 1500-2000 r / min and the cutting feed speed is 0.5-1 mm / s to avoid micro-cracks in the blank due to cutting stress.

[0008] This setting ensures cutting efficiency while preventing excessive cutting stress caused by excessively high rotation speed and localized overheating of the billet, as well as excessive cutting stress caused by excessively fast feed. This effectively prevents micro-cracks in the billet, ensures the integrity of the initial structure of the billet, and lays a good foundation for subsequent sample preparation steps.

[0009] As a preferred embodiment of the present invention, when observing the interference color under a microscope in step S3, an orthogonal polarization mode is used, with the first-order gray-white interference color of quartz as the reference standard, to ensure that the thickness of the blank is precisely controlled within the range of 0.03mm ± 0.002mm.

[0010] This setting meets the standard thickness requirements for transmissive light observation of transparent minerals, avoids errors in judging the optical properties of minerals due to thickness deviations, and improves the accuracy of subsequent rock and mineral identification.

[0011] As a preferred embodiment of the present invention, the curing time of the specially prepared epoxy resin in step S5 is 24-48 hours, the curing environment temperature is controlled at 20-25℃ and the relative humidity is 40%-60%, so as to ensure that the epoxy resin has a compressive strength of ≥80MPa after curing.

[0012] This setting meets the standard thickness requirements for transmissive light observation of transparent minerals, avoids errors in judging the optical properties of minerals due to thickness deviations, and improves the accuracy of subsequent rock and mineral identification.

[0013] As a preferred embodiment of the present invention, the polishing process in step S6 is divided into three stages: rough polishing, medium polishing, and fine polishing. The rough polishing stage employs... Diamond spraying with a particle size of 5-8 minutes, polishing time is 5-8 minutes, and the intermediate polishing stage uses... Alumina polishing slurry with a particle size of 3-5 minutes is used for polishing, and fine polishing is performed using... Polishing slurry with silica particles of a certain size, polishing time is 2-3 minutes.

[0014] This setup allows for a gradual reduction in polishing agent particle size and a reasonable allocation of time from coarse to fine polishing. This process progressively refines and thickens surface scratches, ultimately resulting in a mirror-like surface without visible scratches. The synergistic effect of each stage ensures polishing efficiency while meeting the high requirements for mirror quality in the observation of opaque minerals under reflected light, ensuring that the mineral's reflectivity, color, and other characteristics are clearly discernible.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: High information fidelity: Through the "one body, two sides" design, the transmission light and reflection light observation areas are seamlessly connected on the same sample, ensuring in-situ observation of the co-occurrence relationship between transparent and opaque minerals, avoiding information loss in traditional separation sample preparation, ensuring absolute spatial consistency of data, avoiding misjudgment due to sample heterogeneity, and providing direct microscopic evidence for interpreting the diagenetic and mineralization process; Improved research efficiency: Researchers no longer need to switch between two samples to find the corresponding area; they can simply switch the light source on the microscope to observe the two types of minerals, which effectively improves observation efficiency and accuracy. High sample utilization rate: For precious samples such as meteorites and deep-sea drill cores, a single optical thin section can achieve dual observation functions, maximizing the utilization of sample value, reducing sample consumption, realizing the integration of optical observation and geochemical analysis, and expanding the depth and breadth of rock and mineral identification.

[0016] Revealing key genetic information: It can clearly reveal symbiotic structures (such as stibnite and calcite crystallizing from the same source and being preserved in a clastic form due to later tectonic activity), replacement structures (such as pyrite being interbedded by quartz veins), solid solution separation structures (such as droplet-shaped chalcopyrite in sphalerite), growth zoning (such as the relationship between zircon zoning and surrounding sulfides), etc. These are the core evidence for interpreting the diagenetic and mineralization process. Attached Figure Description

[0017] Figure 1 shows the occurrence of stibnite in sericite phyllite: 1a is a thin section field of view; 1b is a light section field of view. Figure 2 shows the symbiotic and alteration characteristics of stibnite and calcite: 2a is a thin section field-view diagram; 2b is a thin section field-view diagram; 2c is a light section field-view diagram. Figure 3 shows the hydrothermal symbiotic relationship between polymetallic minerals and quartz: 3a is the first field of view of the light section; 3b is the second field of view of the light section. Detailed Implementation

[0018] To further understand the invention's content, features, and effects, the following embodiments are provided and described in detail below.

[0019] Referring to the accompanying drawings, the present invention will now be described in detail. Example 1

[0020] Preparation of thin sections of stibnite gold mine from Hualiangzi: S1. Sample selection and cutting: A sericite phyllite specimen (containing stibnite and calcite symbiosis) from the Hualiangzi gold mine was selected and cut with a diamond saw blade (1800 r / min, feed rate 0.8 mm / s) to obtain a blank of 28 mm × 32 mm and 2.5 mm thickness. The cut surface exposed the cemented structure of stibnite fragments and calcite. S2. Grinding and gluing: Grind one side of the blank with 100-mesh, 400-mesh, and 800-mesh diamond abrasive in sequence. After cleaning with anhydrous ethanol, glue it onto a 25mm×75mm glass slide using room temperature two-component epoxy resin and let it stand for 3 hours for initial curing. S3. Grind to standard sheet thickness: The sheet grinding machine pressure is 0.15MPa. During the grinding process, the sheet is observed under an orthogonal polarizing microscope every 30 seconds. The first-order gray-white interference color of quartz is used as a reference. Finally, the sheet thickness is controlled to 0.03mm. S4. Cover glass and initial curing: After cleaning with deionized water, dry at 80℃ for 12 minutes, add resin with a refractive index of 1.55, cover with a 20mm×25mm cover glass, and let stand at a constant temperature of 28℃ for 5 hours to allow the resin to initially cure. S5, Area Thickening: Polyimide tape covers the covered area, and special epoxy resin (compressive strength 85MPa) is stacked on the uncovered area. Curing is carried out for 36 hours at a temperature of 22℃ and a relative humidity of 50%. S6. Grinding and Polishing: Grinding is performed sequentially using 600 mesh (0.25MPa, 350r / min, 6min), 1000 mesh (0.18MPa, 450r / min, 4min), and 2000 mesh (0.12MPa, 550r / min, 2.5min); Polishing is performed sequentially using... Diamond spraying (0.1MPa, 600r / min, 6min) Alumina polishing slurry (0.08MPa, 700r / min, 4min) Treatment with silica polishing slurry (0.05MPa, 800r / min, 2.5min) to form a mirror finish; S7. Cleaning and Inspection: Ultrasonic cleaning for 8 minutes (deionized water), drying with anhydrous ethanol, and then inspection. Under transmitted light, the interference colors of stibnite fragments and calcite are clear, and under reflected light, the reflectivity characteristics of stibnite are obvious, meeting the standards. Example 2

[0021] Preparation of thin sections of chalcopyrite from the Layikeleke copper mine in Yiwu County: S1. Sample selection and cutting: Quartz vein specimens containing chalcopyrite and pyrite from the Laiklerk copper mine were selected and cut with a diamond saw blade (1600 r / min, feed speed 0.6 mm / s) to obtain blanks of 25 mm × 30 mm and 2 mm thickness. The cut surface exposed the symbiotic structure of chalcopyrite and pyrite. S2. Grinding and gluing: Grind with 100-mesh, 400-mesh, and 800-mesh diamond abrasive in a gradient. Heat and melt solid epoxy resin and glue it onto the glass slide. Let it stand for 2.5 hours for initial curing. S3. Grind to standard sheet thickness: Grinding machine pressure 0.12MPa, orthogonal polarizing microscope with reference to quartz interference color, control the thickness to 0.029mm; S4, Covering and initial curing: Dry at 70℃ for 10 min, cover with resin and let stand at 25℃ for 4.5 h; S5, Area Thickening: The area covered by the epoxy special coating is thickened by stacking special epoxy resin (compressive strength 82MPa), and cured at 20℃ and 45% relative humidity for 40h. S6. Grinding and Polishing: Grinding and polishing stages using 600 mesh (0.2MPa, 300r / min, 5min), 1000 mesh (0.15MPa, 400r / min, 3min), and 2000 mesh (0.1MPa, 500r / min, 2min). Diamond spraying (0.1MPa, 600r / min, 5min) Alumina polishing slurry (0.08MPa, 700r / min, 3min) Treatment with silica polishing slurry (0.05MPa, 800r / min, 2min); S7. Cleaning and Inspection: Ultrasonic cleaning for 5 minutes. Inspection showed that the quartz vein structure was clear under transmitted light, and the reflection characteristics of chalcopyrite and pyrite were identifiable under reflected light, meeting the standard.

[0022] The example results are shown in Figure 1. Figure 1a Thin film field of view (transmitted light, magnification +10×10). Figure 1b The field of view of the light sheet (reflected light, magnification -10×10) shows that the two sub-images correspond to the same observation area of ​​the same sample. Observation and analysis: Using the integrated thin section technique, stibnite (Snt) can be quickly and accurately identified as hydrothermal filling of sericite phyllite, and after subsequent volcanic and tectonic activity, it now exists in clastic form; Combining the integrated thin-film fabrication process of this invention, by instantly switching between transmitted and reflected light observation modes, it is possible to quickly and accurately characterize stibnite (mineral code Sn) as a hydrothermal infill within a sericite phyllite matrix. Due to the influence of later volcanic activity and tectonic activity, the original infilling stibnite has been broken into fragments. The outlines of these fragments and their contact relationship with the sericite phyllite matrix can be simultaneously represented in both fields of view, intuitively presenting the formation period and later alteration process of stibnite, and providing direct microscopic evidence for the temporal relationship between hydrothermal mineralization and tectonic activity. Referring to Figure 2, Figure 2a A thin section field of view (transmitted light, magnification +10×10). Figure 2b Two images of the field of view of the thin section (orthogonal polarized light, magnification -10×10). Figure 2c The field of view of the light sheet (reflected light, magnification -10×10) is divided into three sub-images corresponding to the same observation area of ​​the same sample. Observation and analysis: Using the integrated optical thin-film technology, the reflective and transmitted light sources can be switched instantaneously between optical thin films in the same field of view of the same sample, which can quickly and accurately identify that stibnite (Snt) coexists with calcite (Cal) hydrothermal fluid in the form of hydrothermal fluid, and after subsequent volcanic and tectonic activities, it is now distributed in the form of clastic fragments among quartz (Qtz) fragments. Based on the "one body, two sides" structure of this invention, the transparent crystal morphology of calcite (mineral code Cal) and the distribution characteristics of quartz (mineral code Qtz) fragments can be clearly identified by transmitted light. Orthogonal polarized light is used to confirm the optical properties of calcite. After switching to reflected light, the distribution of stibnite (Snt) can be accurately located. The coordinated observation of the three shows that stibnite and calcite are hydrothermal co-existing minerals, and the two fill the gaps between quartz fragments. Later tectonic activity caused this co-existing assemblage to break into fragments, and the spatial distribution relationship of each mineral fragment corresponds completely in different fields of view, avoiding the misjudgment of mineral co-existence relationships that may be caused by traditional separation and sample preparation.

[0023] See Figure 3. Figure 3a The magnification of the light film field of view is increased by 20×10. Figure 3b The magnification of the two images in the field of view of the light sheet is -20×10, and the two sub-images correspond to the same observation area of ​​the same sample; Observation and Analysis: The process of this invention enables fine observation under reflected light. Through the integrated optical thin-film technology, the reflective and transmitted light sources can be switched instantaneously between optical thin films to observe the types of transparent and metallic minerals, their contact relationships, and their formation sequence. It can quickly and accurately identify molybdenite (Mot), pyrite (Py), chalcopyrite (Ccp), and quartz (Qtz) as contemporaneous hydrothermal symbiotic minerals, confirming that they are products of the same hydrothermal activity period, and providing key microscopic evidence for the study of the composition and evolution of ore-forming fluids.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for integrated fabrication of optical thin films, characterized in that, Includes the following steps: S1. Sample selection and cutting: Select representative rock or mineral specimens according to the research purpose, and cut them with diamond saw blades to obtain blanks with a size of not less than 25mm×30mm and a thickness of 2-3mm, and the cut surface contains the key minerals or structures to be studied. S2. Grinding and bonding: The cut surface of the blank obtained in step 1 is subjected to coarse grinding, fine grinding and fine grinding in sequence to make the flatness of the cut surface meet the requirements for gluing; the flattened cut surface is glued onto a clean glass slide using epoxy resin, wherein the epoxy resin is a two-component resin that solidifies at room temperature or a solid resin that is melted by heating. S3. Grind to standard sheet thickness: The unattached side of the blank is ground using a thin-plate grinding machine. During the grinding process, the pressure is kept uniform, and the interference color is observed under a microscope at preset intervals until the blank thickness reaches the standard thin-plate thickness of 0.03 mm. S4. Cover sheet and initial curing: Clean and dry the blank area that has reached the standard thickness in step 3, cover and seal the area with resin and cover glass, and let it stand until the resin has initially cured. S5, Area Thickening: Use corrosion-resistant, high-strength tape or special coating to completely cover and protect the area that has been covered in step 4. For the area of ​​the blank that has not been covered and needs to be made into a smooth sheet, use special epoxy resin to build up and thicken it to form a solid base, and let it stand until the epoxy resin is completely cured. S6. Grinding and Polishing: For the thickened area in step 5, use diamond grinding discs with 600 mesh, 1000 mesh, and 2000 mesh grit in sequence to grind it so that the surface of the thickened area is close to the same plane as the surface of the cover plate area. Then switch to the polishing machine and use diamond spray, alumina or silica polishing liquid with a woolen polishing disc to polish it until the surface of the thickened area forms a mirror surface without visible scratches. S7. Cleaning and Inspection: The sample is thoroughly cleaned with deionized water or a special cleaning agent to remove residual abrasive and polishing agent from the grinding and polishing process. The optical quality of the cover plate area (interference color, transparency, no cracks) is checked under a transmitted light microscope, and the mirror quality of the polished area (no scratches, uniform reflection) is checked under a reflected light microscope. If both meet the standards, the optical sheet fabrication is complete.

2. The integrated fabrication process for optical thin films as described in claim 1, characterized in that: In step S1, when cutting the blank, the rotation speed of the diamond saw blade is controlled at 1500-2000 r / min and the cutting feed speed is 0.5-1 mm / s to avoid micro-cracks in the blank due to cutting stress.

3. The integrated fabrication process for optical thin films as described in claim 1, characterized in that: In step S3, when observing the interference colors under a microscope, an orthogonal polarization mode is used, with the first-order gray-white interference color of quartz as the reference standard, to ensure that the thickness of the blank is precisely controlled within the range of 0.03mm ± 0.002mm.

4. The integrated fabrication process for optical thin films as described in claim 1, characterized in that: In step S5, the curing time of the specially made epoxy resin is 24-48 hours, the curing environment temperature is controlled at 20-25℃ and the relative humidity is 40%-60%, ensuring that the epoxy resin has a compressive strength of ≥80MPa after curing.

5. The integrated fabrication process for optical thin films as described in claim 1, characterized in that: The polishing process in step S6 is divided into three stages: rough polishing, medium polishing and fine polishing. In the rough polishing stage, diamond spray with a particle size of 5-10μm is used and the polishing time is 5-8 minutes. In the medium polishing stage, alumina polishing slurry with a particle size of 1-3μm is used and the polishing time is 3-5 minutes. In the fine polishing stage, silica polishing slurry with a particle size of 0.05-0.1μm is used and the polishing time is 2-3 minutes.

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