A solid sealing pressure transmission medium for green stone and a preparation method thereof

Abstract

The application provides a Qingtian stone-based solid sealing pressure transmission medium and a preparation method thereof, and relates to the technical field of superhard material synthesis and production. Specifically, the method comprises the following steps: S1. Qingtian stone, hard bauxite, metal oxide and water glass are accurately weighed according to the proportion; S2. The Qingtian stone is crushed into coarse particles, medium particles and fine particles, and the hard bauxite and the metal oxide are ground into powder; S3. The coarse particles of the Qingtian stone and the medium particles of the Qingtian stone are sequentially added to a mixing device, and after being uniformly mixed, the water glass is added and mixed again, and then the fine particles of the Qingtian stone, the hard bauxite powder and the metal oxide powder are added and uniformly stirred; S4. The mixed material is sealed and aged; and S5. The material is pressed and formed, and then baked. The Qingtian stone commonly used for preparing seals is used as the raw material, the hard bauxite and the metal oxide are compounded to produce a synergistic effect, so that the Qingtian stone-based solid sealing pressure transmission medium with high performance is prepared, and the high dependence on the leaf opal produced in Mentougou in the preparation of the solid sealing pressure transmission medium in the prior art is effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of superhard material synthesis and production technology, specifically relating to a Qingtian stone-based solid sealing pressure transmission medium and its preparation method. Background Technology

[0002] Solid sealing pressure-transmitting medium is an important auxiliary material for synthetic diamond production in my country. It is used to seal and encapsulate the growth chamber and uniformly transmit the pressure from the six-sided top hammers. The solid sealing pressure-transmitting medium needs to possess excellent sealing, pressure transmission, insulation, and heat insulation properties. Whether the sealing performance meets the standards is a decisive factor in whether the press will explode. In domestically produced six-sided top presses, gaps exist between the hammers after tightening. The sealing pressure-transmitting medium must not only seal and encapsulate the growth chamber to prevent graphite leakage, but also tightly fill the gaps between the hammers during compression. Simultaneously, this also requires the medium to have insulation properties to prevent short circuits between the hammers that could cause a press explosion. Pressure transmission is crucial for the uniform crystallization of diamond. Only when the growth chamber is uniformly pressurized from all sides can the geological state be optimally restored, allowing carbon atoms to align sequentially on the seed crystals and form qualified diamond particles. Heat insulation is used to ensure the continuous high temperature of the growth chamber; good heat insulation can save energy.

[0003] In China, the primary sealing and pressure-transmitting medium is pyrophyllite powder briquettes. Pyrophyllite is a TOT (Total Oxide-Total) structured clay mineral with a honeycomb-like silicon-oxygen tetrahedron backbone. Adjacent tetrahedrons are rotated in opposite directions at an angle to form a complex triangular network, reducing lateral space. A layer of aluminum-oxygen octahedrons is sandwiched between two layers of tetrahedrons. The upper and lower tetrahedral plates provide four oxygen ions and two hydroxide ions, connected by hydrogen bonds. The crystal structure units are only connected by weak van der Waals forces, making the pyrophyllite plate-like structure easy to slip and dissociate under high pressure. Traditional sealing and pressure-transmitting media are mostly liquids or low-melting-point solid materials such as sodium chloride that rely on high-temperature melting to generate isostatic water pressure. However, these materials cannot be used in six-sided top presses with hammer gaps. The unique crystal structure of pyrophyllite allows the sealing and pressure-transmitting medium to move beyond traditional isostatic water pressure transmission, achieving uniform pressure transmission through interlayer slippage.

[0004] In the 1980s, the synthetic diamond industry used pyrophyllite from Mentougou, Beijing, as the standard raw material for sealing and pressure transmission. Due to the specific 2M-type crystal structure and associated mineral composition of Mentougou pyrophyllite, it exhibited excellent sealing and pressure transmission properties. However, with the gradual depletion of Mentougou pyrophyllite resources, the research on sealing and pressure transmission media for new domestically produced hinged six-sided top presses has become an urgent task for the synthetic diamond industry.

[0005] Chinese invention patent application number 201310327139.2 discloses a method for preparing an optimized combination type of sealing pressure transmission medium. This method uses various silica-alumina ores from different regions as raw materials and optimizes their combination to form a novel artificially synthesized sealing pressure transmission medium. Four to five different silica-alumina ores are combined according to their weight ratios and averaged to optimize the chemical composition of the mixed sample, making it similar to pyrophyllite. 6% mica and 0.9% vermiculite are added by weight, along with a 5% polyvinyl alcohol solution, and the mixture is stirred until homogeneous. However, this method has complex proportions, and the quality of raw materials from different mineral sources is unstable, which is not conducive to industrial-scale production. Furthermore, this method essentially only involves a conventional combination of minerals from different origins by reducing the composition of pyrophyllite from Mentougou, Beijing. Chinese invention patent application No. 201510352027.1 discloses a method for preparing pyrophyllite blocks for the synthesis of superhard materials. The method uses pyrophyllite, gibbsite, kaolinite, and hematite as raw materials, which are crushed separately and then mixed with a sodium silicate solution at a weight ratio of 5-10%. The mixture is stirred evenly, pressed into shape, and baked at 150-250℃ for 15-25 hours. However, the high-temperature phase transformation of kaolinite easily causes the press to explode or blast. Chinese invention patent application No. 201110188675.X discloses an additive for pyrophyllite sealing and pressure transmission media, whose main components are symbiotic minerals of boehmite and diaspore. This additive is used to mix with ordinary pyrophyllite powder to improve the chemical composition and enhance sealing and insulation properties. However, this solution cannot fundamentally solve the problem of ordinary pyrophyllite powder easily exploding.

[0006] To ensure the sustainable development of the synthetic diamond industry, prevent machine explosions and blasting during diamond preparation, and address the dependence on the Mentougou pyrophyllite mine in Beijing in existing technologies, proposing a novel solid-sealed pressure-transmitting medium is of significant practical importance. In summary, overcoming the shortage of mineral resources and dependence on high-purity Mentougou pyrophyllite mines, and preparing a solid-sealed pressure-transmitting medium with excellent sealing, pressure transmission, insulation, and heat insulation properties for synthetic diamonds using readily available tailings resources, is a technical problem urgently needing to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing a solid sealing and pressure-transmitting medium based on Qingtian stone. It primarily addresses the problem of the high dependence on high-purity pyrophyllite from Mentougou, Beijing, in the preparation of sealing and pressure-transmitting media using existing technologies, and explores an alternative solution with widely available raw materials, low cost, and better product performance. The solid sealing and pressure-transmitting medium prepared according to this invention can simultaneously achieve high-performance sealing and pressure transmission in the production of synthetic diamonds, while also possessing excellent insulation and heat insulation properties, which is of great significance for ensuring the safe and efficient production of synthetic diamonds.

[0008] To achieve the above objectives, this invention provides a method for preparing a Qingtian stone-based solid sealing pressure transmission medium, specifically including the following steps:

[0009] S1. Accurately weigh out the following components according to the specified proportions: Qingtian stone, diaspore, metal oxides, and water glass.

[0010] S2 crushes Qingtian stone into three particle sizes: coarse, medium and fine, and grinds diaspore and metal oxides into powder.

[0011] S3 adds coarse Qingtian stone particles and medium Qingtian stone particles in sequence to the mixing device, mixes them evenly, adds water glass and mixes them again, then adds fine Qingtian stone particles, diaspore powder and metal oxide powder, and stirs them evenly.

[0012] S4. Seal and age the mixture obtained in step S3.

[0013] S5. Place the material obtained in step S4 into a mold, press it into shape, and bake it to obtain the final product.

[0014] In a preferred embodiment, step S1 includes, by weight, 70-80 parts of Qingtian stone, 10-20 parts of diaspore, 0-5 parts of metal oxide, and 7-10 parts of water glass;

[0015] Preferably, by weight, it includes 75-80 parts of Qingtian stone, 10-20 parts of diaspore, 1-3 parts of metal oxides, and 7-9 parts of water glass;

[0016] More preferably, by weight, it includes 77 parts of Qingtian stone, 15 parts of diaspore, 1 part of metal oxide, and 7 parts of water glass.

[0017] In a preferred embodiment, in step S1, the total weight of the qingtian stone, diaspore, metal oxide and water glass is 100 parts, and the weight of the metal oxide is not 0 parts.

[0018] In a preferred embodiment, in step S1, the Qingtian stone is Qingtian stone tailings produced in Qingtian County, Zhejiang Province, and its chemical composition is: SiO2 60-75%, Al2O3 25-40%, FeO < 0.5%, TiO2 < 0.5%.

[0019] In a preferred embodiment, in step S1, the chemical composition of the diaspore is: Al2O3 > 85%.

[0020] In a preferred embodiment, in step S1, the metal oxide includes one or both of rutile and hematite.

[0021] In a preferred embodiment, in step S1, the total chemical composition of the zirconia, diaspore and metal oxides is: SiO2 60-75%, Al2O3 25-40%, FeO 0-0.5%, TiO2 0-0.5%.

[0022] In a preferred embodiment, in step S1, the water glass has a Baumé degree of 38-42, a modulus of 3-3.5, a Na2O content of 8-9%, and a SiO2 content of 27-28.5%.

[0023] The main raw material used in this invention is Qingtian stone, a metamorphic intermediate-acidic volcanic rock called rhyolite tuff. Its main mineral component is pyrophyllite, along with quartz, sericite, sillimanite, epidote, and diaspore. It has a variety of colors, including red, yellow, blue, white, and black. The color of the rock is related to its chemical composition; a high ferric oxide content results in a red color, a low content in a yellow color, and an even lower content in a bluish-white color. The rock has a medium hardness. Because it contains minerals such as pyrophyllite, sericite, and diaspore, it has a slippery feel. It is mainly produced in Shankou Town, Qingtian County, Zhejiang Province, hence the name "Qingtian stone." In this invention, the Qingtian stone used is the tailings collected after seal production. Specifically, it refers to the scraps produced during the seal production process after the Qingtian stone ore has been crushed, beneficiated, and impurities removed. These scraps are difficult to reprocess due to their varied shapes and low economic value. Based on this, the present invention has conducted extensive research and exploration on Qingtian stone tailings in order to expand its resource utilization methods and avoid solid waste accumulation.

[0024] In a preferred embodiment, in step S2, the coarse-grained Qingtian stone has a particle size range of 8-16 mesh, the medium-grained Qingtian stone has a particle size range of 16-30 mesh, and the fine-grained Qingtian stone has a particle size of less than 30 mesh.

[0025] In a preferred embodiment, in step S2, the diaspore and metal oxide are ground to a particle size of less than 30 mesh.

[0026] In a preferred embodiment, in step S3, the mass ratio of coarse, medium, and fine Qingtian stone particles is 4:3:3, meaning that 8-16 mesh coarse particles account for 40% of the total weight of the Qingtian stone tailings powder, 16-30 mesh medium particles account for 30%, and fine particles below 30 mesh account for 30%. In this invention, by crushing Qingtian stone into three particle sizes (coarse, medium, and fine) and then mixing them sequentially, the porosity of the compressed briquettes can be effectively reduced, making them more compact. The resulting sample has a molding density of 2.52 g / cm³. 3 above.

[0027] In a preferred embodiment, in step S4, the sealing and aging time is 12-24 hours.

[0028] In a preferred embodiment, in step S5, the calcination process is as follows: first, the temperature is raised to 90-110℃ and held for 1-3 hours, then the temperature is raised to 180-220℃ and held for 1-3 hours, and finally the temperature is raised to 270-330℃ and held for 1-3 hours.

[0029] Preferably, the roasting process is as follows: first, heat to 100℃ and hold for 2-3 hours, then heat to 200℃ and hold for 2-3 hours, and finally heat to 300℃ and hold for 2-3 hours.

[0030] In a preferred embodiment, in step S5, the heating rate is 4-6°C / min, preferably 5°C / min.

[0031] Another objective of this invention is to provide a Qingtian stone-based solid sealing and pressure-transmitting medium prepared by any of the above methods. This invention solves the current problem of extreme shortage of pyrophyllite in Mentougou District, allowing the preparation of high-performance solid sealing and pressure-transmitting media using Qingtian stone mine tailings. Qingtian stone reserves are abundant and inexpensive. Using it as a raw material not only expands the utilization pathways of Qingtian stone resources but also effectively solves the problem of tailings treatment, reduces solid waste accumulation, and lowers production costs.

[0032] Furthermore, the performance of the prepared Qingtian stone-based solid sealing pressure transmission medium far exceeds that of the sealing medium obtained from high-purity pyrophyllite in Mentougou. Specifically, the density of the Qingtian stone-based solid sealing pressure transmission medium is 2.52 g / cm³. 3 The above properties include a compressive strength of 63.28 MPa or higher, a thermal conductivity of 3.16-4.03 W / (m*K), and an electrical conductivity of 1.19-8.78*10. -7 S / m.

[0033] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0034] 1. This invention uses Qingtian stone tailings as the main raw material. The pyrophyllite ore contained therein can provide pressure transmission, sealing, and thermal insulation. The addition of diaspore powder can effectively improve its mechanical properties and enhance its pressure transmission and sealing performance. The addition of metal oxides can have a synergistic effect with Qingtian stone tailings and diaspore powder, further improving the various properties of the solid sealing and pressure transmission medium. For example, the addition of rutile powder can reduce its thermal conductivity and improve its heat insulation performance, with a thermal conductivity of over 3.16 W / m·K; the addition of hematite can reduce the internal friction coefficient and improve the sealing and pressure transmission performance; water glass helps to bind the above minerals into blocks and improve mechanical properties.

[0035] 2. Regarding the preparation method, this invention uses a particle size distribution method to thoroughly mix Qingtian stone tailings with other minerals, further reducing the porosity of the compressed blocks and increasing the sample density. Only through the rational proportioning of raw materials and the particle size distribution method used can the compressed blocks be made dense and conducive to calcination. The calcination process used in this invention takes only 3-9 hours, far less than the long calcination processes in existing technologies, effectively saving energy and increasing production capacity. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0037] This invention provides a Qingtian stone-based solid sealing pressure transmission medium and its preparation method, solving the problem of high dependence on high-purity pyrophyllite produced in Mentougou, Beijing, when preparing sealing pressure transmission media in the prior art.

[0038] Although the Qingtian stone used in this invention contains pyrophyllite, its mineral composition is completely different from that of the Mentougou pyrophyllite. Specifically, the Mentougou pyrophyllite contains approximately 70-80% pyrophyllite, exhibiting flaky cryptocrystalline structure below 5μm under crossed polarized light, accompanied by 20-30% diaspore and trace amounts of chlorite, rutile, and hematite. In contrast, the Qingtian stone used in this invention contains over 95% pyrophyllite, exhibiting 5-10μm needle-like cryptocrystalline structure under crossed polarized light, accompanied by a small amount of hematite. Furthermore, although my country has the world's largest pyrophyllite mineral resources, with hundreds of deposits, only pyrophyllite can be used as a sealing and pressure-transmitting medium for synthesizing diamonds. As stated on page 88 of Song Xiangquan's "Strategic Analysis of Mineral Resources - Pyrophyllite," "The Mentougou pyrophyllite mine in Beijing is currently the only place in my country producing artificial diamond blanks." It is evident that pyrophyllite deposits from different origins, with varying chemical compositions and associated minerals, exhibit fundamental differences. Furthermore, the pyrophyllite used for preparing solid sealing and pressure-transmitting media in synthetic diamond production is limited to that from the Mentougou pyrophyllite mine in Beijing. Based on the severe shortage of Mentougou pyrophyllite resources, this invention utilizes Qingtian stone, conventionally used for seal stones, as raw material to explore a method for preparing solid sealing and pressure-transmitting media for synthetic diamond from tailings of this mineral, achieving excellent technical results.

[0039] The technical solution of this application will be described in detail below through specific embodiments:

[0040] Unless otherwise specified, the technical means used in this invention are conventional means well known to those skilled in the art. All raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Unless otherwise specified, all reagents used in this invention are of analytical grade. The room temperature described in this invention is 25±5℃.

[0041] The Qingtian stone tailings used in this embodiment of the invention are produced in Qingtian County, Zhejiang Province. The main mineral components are pyrophyllite >95wt% and hematite <0.5wt%, and the color is bluish-green. The diaspore ore used in this embodiment of the invention contains diaspore content >95wt%.

[0042] In all embodiments of the present invention, the total chemical composition of the qingtian stone, diaspore and metal oxides used is: SiO2 60-75%, Al2O3 25-40%, FeO 0-0.5%, TiO2 0-0.5%.

[0043] Example 1

[0044] S1 is made by accurately weighing 78 wt% of Qingtian stone, 15 wt% of diaspore and 7 wt% of water glass according to the formula;

[0045] S2 crushes Qingtian stone into three particle sizes: coarse (8-16 mesh), medium (16-30 mesh), and fine (below 30 mesh), with a mass ratio of coarse, medium, and fine particles of 4:3:3. It also grinds diaspore and metal oxides to below 30 mesh.

[0046] S3 adds coarse Qingtian stone particles and medium Qingtian stone particles in sequence to the mixing device, mixes them evenly, adds water glass and mixes them again, then adds fine Qingtian stone particles, diaspore powder and metal oxide powder, and stirs them evenly.

[0047] S4 Seal the mixture obtained in step S3 and age it at room temperature for 24 hours.

[0048] S5. Place the material obtained in step S4 into a pressing mold and press it into shape. Then, bake it by first heating it to 100°C and holding it for 3 hours, then heating it to 200°C and holding it for 3 hours, and finally heating it to 300°C and holding it for 3 hours to obtain the sealing pressure transmission medium.

[0049] In this embodiment, the product's density was measured to be 2.55 g / cm³ using Archimedes' displacement method. 3 The uniaxial compression test yielded a compressive strength of 63.33 MPa, which is higher than existing samples on the market. It is not easily deformed under high pressure and exhibits good sealing and pressure transmission properties. The triaxial compression test showed an internal friction angle of 25.69°, and the thermal conductivity measured by a laser thermal conductivity meter was 4.03 W / (m*K), indicating good thermal insulation. The LCR tester measured an electrical conductivity of 1.19*10⁻⁶. -7 S / m is an insulating material. In summary, the product obtained in this embodiment can meet the requirements for sealing and pressure transmission.

[0050] Example 2

[0051] S1 is made by accurately weighing 77 wt% of Qingtian stone, 15 wt% of diaspore, 1 wt% of rutile and 7 wt% of water glass according to the formula;

[0052] S2 crushes Qingtian stone into three particle sizes: coarse (8-16 mesh), medium (16-30 mesh), and fine (below 30 mesh), with a mass ratio of coarse, medium, and fine particles of 4:3:3. It also grinds diaspore and metal oxides to below 30 mesh.

[0053] S3 adds coarse Qingtian stone particles and medium Qingtian stone particles in sequence to the mixing device, mixes them evenly, adds water glass and mixes them again, then adds fine Qingtian stone particles, diaspore powder and metal oxide powder, and stirs them evenly.

[0054] S4 Seal the mixture obtained in step S3 and age it at room temperature for 24 hours.

[0055] S5. Place the material obtained in step S4 into a pressing mold and press it into shape. Then, bake it by first heating it to 100°C and holding it for 3 hours, then heating it to 200°C and holding it for 3 hours, and finally heating it to 300°C and holding it for 3 hours to obtain the sealing pressure transmission medium.

[0056] In this embodiment, the product's density was measured to be 2.52 g / cm³ using Archimedes' displacement method. 3 The uniaxial compression test yielded a compressive strength of 63.36 MPa, which is higher than existing samples on the market. It is less prone to deformation under high pressure and exhibits good sealing and pressure transmission properties. The triaxial compression test yielded an internal friction angle of 13.61°. These test data demonstrate that the product of this invention effectively solves the problem of pyrophyllite powder easily exploding. A laser thermal conductivity meter measured a thermal conductivity of 3.16 W / (m*K), indicating good heat retention. An LCR meter measured an electrical conductivity of 1.29*10⁻⁶. -7 S / m represents the insulating material. In summary, the addition of rutile reduces the internal friction angle of the product, increases its slippage under high pressure, and improves overall sealing performance.

[0057] Example 3

[0058] S1 is made by accurately weighing 77wt% of Qingtian stone, 15wt% of diaspore, 1wt% of hematite and 7wt% of water glass according to the formula;

[0059] S2 crushes Qingtian stone into three particle sizes: coarse (8-16 mesh), medium (16-30 mesh), and fine (below 30 mesh), with a mass ratio of coarse, medium, and fine particles of 4:3:3. It also grinds diaspore and metal oxides to below 30 mesh.

[0060] S3 adds coarse Qingtian stone particles and medium Qingtian stone particles in sequence to the mixing device, mixes them evenly, adds water glass and mixes them again, then adds fine Qingtian stone particles, diaspore powder and metal oxide powder, and stirs them evenly.

[0061] S4 Seal the mixture obtained in step S3 and age it at room temperature for 24 hours.

[0062] S5. Place the material obtained in step S4 into a pressing mold and press it into shape. Then, bake it by first heating it to 100°C and holding it for 3 hours, then heating it to 200°C and holding it for 3 hours, and finally heating it to 300°C and holding it for 3 hours to obtain the sealing pressure transmission medium.

[0063] In this embodiment, the product's density was measured to be 2.54 g / cm³ using Archimedes' displacement method. 3 The uniaxial compression test yielded a compressive strength of 63.28 MPa, which is higher than existing samples on the market. It is less prone to deformation under high pressure and exhibits good sealing and pressure transmission properties. The triaxial compression test yielded an internal friction angle of 22.56°. These test data demonstrate that the product of this invention effectively solves the problem of pyrophyllite powder easily exploding in machines. A laser thermal conductivity meter measured a thermal conductivity of 4.03 W / (m*K), indicating good heat retention. An LCR meter measured an electrical conductivity of 8.78*10⁻⁶. -7 S / m indicates the presence of insulating material. In summary, the addition of hematite reduces the internal friction angle of the product, improves overall sealing, and has a smaller impact on density than rutile.

[0064] Comparative Example 1

[0065] S1 is made by accurately weighing 68wt% of Qingtian stone, 25wt% of diaspore and 7wt% of water glass according to the formula;

[0066] S2 crushes Qingtian stone into three particle sizes: coarse (8-16 mesh), medium (16-30 mesh), and fine (below 30 mesh), with a mass ratio of coarse, medium, and fine particles of 4:3:3. It also grinds diaspore to below 30 mesh.

[0067] S3 adds coarse Qingtian stone and medium Qingtian stone in sequence to the mixing device, mixes evenly, adds water glass and mixes again, then adds fine Qingtian stone and diaspore powder and stirs evenly.

[0068] S4 Seal the mixture obtained in step S3 and age it at room temperature for 24 hours.

[0069] S5. Place the material obtained in step S4 into a pressing mold and press it into shape. Then, bake it by first heating it to 100°C and holding it for 3 hours, then heating it to 200°C and holding it for 3 hours, and finally heating it to 300°C and holding it for 3 hours to obtain the sealing pressure transmission medium.

[0070] In this embodiment, the product's density was measured to be 2.52 g / cm³ using Archimedes' displacement method. 3 The uniaxial compressive strength was measured to be 63.35 MPa. However, the sample block exhibited non-dense phenomena such as powder and slag shedding, which was determined to be due to the excessively high content of gibbsite, resulting in a significant increase in porosity, reduced sealing performance, and adverse effects on production.

[0071] Comparative Example 2

[0072] S1 is made by accurately weighing 80wt% of Qingtian stone, 15wt% of diaspore and 5wt% of water glass according to the formula;

[0073] S2 crushes Qingtian stone into three particle sizes: coarse (8-16 mesh), medium (16-30 mesh), and fine (below 30 mesh), with a mass ratio of coarse, medium, and fine particles of 4:3:3. It also grinds diaspore to below 30 mesh.

[0074] S3 adds coarse Qingtian stone and medium Qingtian stone in sequence to the mixing device, mixes evenly, adds water glass and mixes again, then adds fine Qingtian stone and diaspore powder and stirs evenly.

[0075] S4 Seal the mixture obtained in step S3 and age it at room temperature for 24 hours.

[0076] S5. Place the material obtained in step S4 into a pressing mold and press it into shape. Then, bake it by first heating it to 100°C and holding it for 3 hours, then heating it to 200°C and holding it for 3 hours, and finally heating it to 300°C and holding it for 3 hours to obtain the sealing pressure transmission medium.

[0077] In this embodiment, the product's density was measured to be 2.49 g / cm³ using Archimedes' displacement method. 3 The uniaxial compressive strength test showed a compressive strength of 40.82 MPa, indicating that the compressive strength decreased significantly after the water glass content was reduced, falling below the product standard.

[0078] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a Qingtian stone-based solid sealing pressure transmission medium, characterized in that, Includes the following steps: S1. Accurately weigh out the following components according to the specified proportions: Qingtian stone, diaspore, metal oxides, and water glass. S2 crushes Qingtian stone into three particle sizes: coarse, medium and fine, and grinds diaspore and metal oxides into powder. S3 adds coarse Qingtian stone particles and medium Qingtian stone particles in sequence to the mixing device, mixes them evenly, adds water glass and mixes them again, then adds fine Qingtian stone particles, diaspore powder and metal oxide powder, and stirs them evenly. S4. Seal and age the mixture obtained in step S3. S5. Place the material obtained in step S4 into a mold, press it into shape, and bake it to obtain the final product. In step S1, by weight, the composition includes 70-80 parts of Qingtian stone, 10-20 parts of diaspore, 0-5 parts of metal oxide, and 7-10 parts of water glass; the metal oxide is rutile or hematite. In step S2, the coarse-grained Qingtian stone has a particle size range of 8-16 mesh, the medium-grained Qingtian stone has a particle size range of 16-30 mesh, and the fine-grained Qingtian stone has a particle size of less than 30 mesh.

2. The preparation method of the Qingtian stone-based solid sealing pressure transmission medium as described in claim 1, characterized in that, In step S1, the total weight of the qingtian stone, diaspore, metal oxide and water glass is 100 parts, and the weight of the metal oxide is not 0 parts.

3. The preparation method of the Qingtian stone-based solid sealing pressure transmission medium as described in claim 1, characterized in that, In step S1, the Qingtian stone is the tailings of Qingtian stone produced in Qingtian County, Zhejiang Province, and its chemical composition is: SiO2 60-75%, Al2O3 25-40%, FeO <0.5%, TiO2 <0.5%; The chemical composition of the diaspore is: Al2O3 > 85%.

4. The preparation method of the Qingtian stone-based solid sealing pressure transmission medium as described in claim 1, characterized in that, In step S3, the mass ratio of coarse-grained, medium-grained, and fine-grained Qingtian stone is 4:3:

3.

5. The preparation method of the Qingtian stone-based solid sealing pressure transmission medium as described in claim 1, characterized in that, In step S5, the roasting process is as follows: first, heat to 90-110℃ and hold for 1-3 hours, then heat to 180-220℃ and hold for 1-3 hours, and finally heat to 270-330℃ and hold for 1-3 hours.

6. The Qingtian stone-based solid sealing pressure transmission medium prepared by the method according to any one of claims 1-5.

7. The Qingtian stone-based solid sealing pressure transmission medium as described in claim 6, characterized in that, The density of the Qingtian stone-based solid sealing pressure transmission medium is 2.52 g / cm³. 3 The above properties include a compressive strength of 63.28 MPa or higher, a thermal conductivity of 3.16-4.03 W / (m*K), and an electrical conductivity of 1.19-8.78*10. -7 S / m.