Isostatic pressing low-heat-conduction low-iron tin bath bottom brick and preparation method thereof
The tin bath bottom bricks prepared by using low thermal conductivity materials and sintering processes have solved the problems of easy floating and high thermal conductivity of tin bath bottom bricks at high temperatures, thus achieving long-term stable operation of the tin bath and improving the quality of glass products.
Patent Information
- Application Number
- CN202511180243.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2025-11-14
AI Technical Summary
The existing bottom bricks of the tin bath are prone to floating at high temperatures, which requires high installation standards, affects the lifespan of the tin bath and the quality of glass products. In addition, the existing materials have high thermal conductivity at high temperatures, making it difficult to meet the requirements for long-term normal operation.
By using a low thermal conductivity copper-alumina-alumina composite porous material and modified silica powder, combined with a specific sintering process, a tin bath bottom brick with low thermal conductivity and low iron content was prepared. By controlling the porosity and structural uniformity, the compressive strength and hydrogen diffusivity were improved.
The prepared tin bath bottom brick has high porosity, and its apparent porosity, compressive strength, hydrogen diffusivity, bulk density and thermal expansion coefficient are superior to existing standards. It also reduces thermal conductivity, ensuring the long-term normal operation of the tin bath and the quality of glass products.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of tin bath bottom brick production technology, specifically to isostatic pressing low thermal conductivity and low iron tin bath floor bricks and their preparation method. Background Technology
[0002] The float glass production process consists of four steps: mixing, glass melting, forming and annealing, and cold end removal. The forming process takes place in a tin bath filled with protective gas. As molten glass continuously flows from the furnace and floats on the surface of the molten tin, it spreads, thins, and cools under the influence of gravity and surface tension, forming a glass strip with flat surfaces. This strip is then guided onto a transition roller table and, as the rollers rotate, enters the annealing furnace. After annealing and cutting, the float glass product is obtained. The tank containing the molten tin is surrounded by tin bath bottom bricks to prevent oxidation of the tin. These bottom bricks are a key refractory material in float glass forming.
[0003] The bottom bricks of the tin bath are composed of many individual bricks. Molten tin has a higher density than the bottom bricks at 1000℃, causing them to float. Therefore, each bottom brick must be fixed to the bottom plate using bottom studs. The studs are welded to the bottom plate. The design of the bottom bricks should emphasize the inclusion of expansion joints. The installation of the bottom bricks is a high-standard and demanding task. The quality of the installation directly affects the production of float glass after commissioning, impacting the service life of the tin bath and the quality of the glass products. With the increasing lifespan of melting furnaces, higher requirements are placed on the refractory materials of the tin bath, and the bottom bricks are a key structural material affecting the long-term normal operation of the tin bath. Therefore, the design and manufacturing process of the bottom bricks still require continuous research and improvement. Summary of the Invention
[0004] To address the problems existing in the background technology, the present invention provides a tin bath bottom brick that is crack-free, structurally uniform, has low foaming, high strain rate, and low permeability. Its preparation method includes the following steps:
[0005] Step (1): Add the first-grade hard clay and high-quality clay powder into a ball mill, mill for 3-4 hours, and sieve to obtain a mixture;
[0006] Step (2): Add water to the microporous mullite aggregate and the mixture and premix for 0.5 to 1 hour. Add copper-aluminum-alumina composite porous material, modified silica powder and additives and continue mixing for 1 to 2 hours. After mixing evenly, pour into the mold.
[0007] Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 4-5 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 20-24 hours to obtain the blank tin bath bottom brick.
[0008] Step (4): Place the blank tin bath bottom bricks in the drying kiln. In the first stage, raise the temperature from room temperature to 200-250℃ at a rate of 3-5℃ / h and hold for 1-1.5 days. In the second stage, raise the temperature from 200-250℃ to 550-600℃ at a rate of 10-15℃ / h and hold for 1-2 days. In the third stage, raise the temperature from 550-600℃ to 950-1050℃ at a rate of 10-15℃ / h and hold for 2-3 days. In the fourth stage, raise the temperature from 950-1050℃ to 1400-1450℃ at a rate of 3-5℃ / h and hold for 2-3 days.
[0009] Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick;
[0010] By weight: 30-40 parts of microporous mullite aggregate;
[0011] 10-15 parts of copper-aluminum-alumina composite porous material;
[0012] 10-15 parts of modified silica powder;
[0013] 20-30 parts of the mixture;
[0014] Additives 1 to 10 parts;
[0015] 20-30 parts water.
[0016] Preferably, the ball mill speed is 650 rpm, and the ratio of balls:material:water is 2:3:2.
[0017] Preferably, the sieve mesh size is 200 mesh.
[0018] Preferably, the preparation steps of the copper-aluminum-alumina composite porous material are as follows: weigh 35 parts of 200-mesh electrolytic copper powder, 25 parts of 250-mesh aluminum powder, 25 parts of alumina fiber and 10 parts of 100-mesh industrial salt, mix them evenly, put them into a mold, press them into shape, then calcine them at 1200℃ for 20-24 hours, cool them to room temperature, and then crush them into particles with an average particle size of 250μm, and set them aside for use.
[0019] Preferably, the microporous mullite aggregate contains 72-77% Al2O3 and 23-29% SiO2.
[0020] Preferably, the copper-aluminum-alumina composite porous material contains 55-60% Cu, 8-10% Al, and 15-20% Al2O3.
[0021] Preferably, the preparation steps of the modified silica powder are as follows:
[0022] Step (a): Soak silicon carbide in a 10% dilute hydrochloric acid solution for 30 minutes, filter, and then dry in a 120°C blower dryer for 2 to 2.5 hours to remove metal impurities and moisture interference;
[0023] Step (b): The cleaned silicon carbide is added to a vertical ball mill at a speed of 200 rpm and pulverized into 500-mesh silicon carbide powder at a ball:material ratio of 8:1.
[0024] Step (c): Dissolve 500 mg of tetraethyl orthosilicate in 10 ml of ethanol, add 2-3 drops of hydrochloric acid, and then stir until a stable sol is formed. Then add silane coupling agent KH-550 to it, and use the dip-coating method to bring silicon carbide particles into contact with the silicon sol to deposit a silicon-based thin film on the surface of silicon carbide.
[0025] Step (d): After coating, the residual solvent is removed by blowing air and then calcined at 650°C in a nitrogen atmosphere for 8-10 hours to promote the crystallization of the silicon-based material into a stable form. After cooling, it is placed for later use.
[0026] Preferably, the additive is one or more of epoxy resin and amino resin.
[0027] Preferably, the mass fraction ratio of primary hard clay to high-quality clay powder in the mixture is 1:1.
[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0029] Studies have shown that higher porosity leads to greater hydrogen diffusivity, as well as higher permeability and strain rate of the brick. The porosity of the tin bath bottom bricks prepared by this invention is 29-33%, which is higher than that of commercially available tin bath bottom bricks. Furthermore, the tin bath bottom bricks prepared by this invention exhibit dimensional accuracy, are crack-free, and have a uniform structure. Moreover, their compressive strength, hydrogen diffusivity, apparent porosity, bulk density, thermal expansion coefficient, and thermal conductivity are significantly superior to the JC / T926-2003 "Tin Bath Bottom Bricks for Float Glass Kilns" building materials industry standard published in my country in 2003.
[0030] The thermal conductivity of silicon carbide changes with temperature; it decreases when the temperature rises above 800℃. This invention modifies silicon micropowder by adding silicon carbide, thereby reducing the thermal conductivity of the tin bath bottom brick. The preparation method described in this invention is simple, low-cost, and slight changes in preparation conditions will not significantly affect the quality of the tin bath bottom brick. Detailed Implementation
[0031] The embodiments of the technical solution of the present invention will be described in detail below with reference to the examples. The following examples are only used to illustrate the technical solution of the present invention more clearly, and are therefore only examples, and should not be used to limit the scope of protection of the present invention. It should be noted that unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, can be obtained commercially.
[0032] In this invention, unless otherwise stated, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between "0~5" have been listed herein, and "0~5" is simply an abbreviation of these numerical combinations.
[0033] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.
[0034] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially; for example, the method includes steps (1) and (2), indicating that the method may include steps (1) and (2) performed sequentially, or may include steps (2) and (1) performed sequentially; for example, the method may also include step (3), indicating that step (3) may be added to the method in any order, for example, the method may include steps (1), (2) and (3), or may include steps (1), (3) and (2), or may include steps (3), (1) and (2), etc.
[0035] In this invention, unless otherwise specified, the specific values and substances in the embodiments herein can be combined with other features described herein; for example, if the specification mentions a reaction temperature of 10 to 100°C, while the embodiment mentions a reaction temperature of 20°C, then it can be considered that the range of 10 to 20°C or the range of 20 to 100°C has been specifically disclosed herein, and this range can be combined with other features described herein to form a new technical solution.
[0036] Preparation of copper-aluminum-alumina composite porous materials:
[0037] Weigh out 35 parts by weight of 200-mesh electrolytic copper powder, 25 parts by weight of 250-mesh aluminum powder, 25 parts by weight of alumina fiber and 10 parts by weight of 100-mesh industrial salt, mix them evenly, put them into a mold, press them into shape at 30 MPa, then calcine them at 1200℃ for 20-24 hours, cool them to room temperature, and crush them into particles with an average particle size of 250 μm to obtain copper-aluminum-alumina composite porous material, which is then set aside for later use.
[0038] Preparation of modified silica powder:
[0039] Step (a): Soak 5g of silicon carbide in 500ml of 10% dilute hydrochloric acid solution for 30 minutes, filter, and then dry in a 120℃ forced-air dryer for 2-2.5 hours to remove metal impurities and moisture interference;
[0040] Step (b): The cleaned silicon carbide is added to a vertical ball mill at a speed of 200 rpm and pulverized into 500-mesh silicon carbide powder at a ball:material ratio of 8:1.
[0041] Step (c): Dissolve 5g of tetraethyl orthosilicate in 100ml of ethanol, add 2-3 drops of hydrochloric acid, and then stir until a stable sol is formed. Then add 50mg of silane coupling agent KH-550 and use the dip-coating method to bring silicon carbide particles into contact with the silica sol to deposit a silicon-based thin film on the surface of silicon carbide.
[0042] Step (d): After coating, the residual solvent is removed by blowing air and then calcined at 650°C in a nitrogen atmosphere for 8-10 hours to promote the crystallization of silicon-based materials into a stable form. After cooling, modified silicon micro powder is obtained and set aside for later use.
[0043] Example 1
[0044] Step (1): Add grade 1 hard clay material and high-quality clay powder with a mass fraction ratio of 1:1 to a ball mill at 650 rpm, and ball mill for 3-4 hours. Then pass the mixture through a 200-mesh sieve to obtain the mixture.
[0045] Step (2): Add 20 parts of water to 31 parts of microporous mullite aggregate and 22 parts of mixture and premix for 1 hour. Add 10 parts of copper-aluminum-alumina composite porous material, 15 parts of modified silica powder and 2 parts of epoxy resin and continue mixing for 1 hour. After mixing evenly, pour into the mold.
[0046] Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 4 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 24 hours to cure it and obtain the blank tin bath bottom brick.
[0047] Step (4): Place the blank tin bath bottom brick in the drying kiln. In the first stage, the temperature is increased from room temperature to 200℃ at a rate of 5℃ / h and held for 1.5 days. In the second stage, the temperature is increased from 200℃ to 600℃ at a rate of 15℃ / h and held for 2 days. In the third stage, the temperature is increased from 600℃ to 1050℃ at a rate of 15℃ / h and held for 3 days. In the fourth stage, the temperature is increased from 1050℃ to ~1450℃ at a rate of 5℃ / h and held for 3 days.
[0048] Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick.
[0049] Example 2
[0050] Step (1): Add grade 1 hard clay material and high-quality clay powder with a mass fraction ratio of 1:1 to a ball mill at 650 rpm, and ball mill for 3-4 hours. Then pass the mixture through a 200-mesh sieve to obtain the mixture.
[0051] Step (2): Add 20 parts of water to 31 parts of microporous mullite aggregate and 22 parts of mixture and premix for 1 hour. Add 10 parts of copper-aluminum-alumina composite porous material, 15 parts of modified silica powder and 2 parts of amino resin and continue mixing for 1 hour. After mixing evenly, pour into the mold.
[0052] Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 4 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 24 hours to cure it and obtain the blank tin bath bottom brick.
[0053] Step (4): Place the blank tin bath bottom brick in the drying kiln. In the first stage, the temperature is raised from room temperature to 200℃ at a rate of 3-5℃ / h and held for 1.5 days. In the second stage, the temperature is raised from 200℃ to 600℃ at a rate of 15℃ / h and held for 2 days. In the third stage, the temperature is raised from 600℃ to 1050℃ at a rate of 15℃ / h and held for 3 days. In the fourth stage, the temperature is raised from 1050℃ to ~1450℃ at a rate of 5℃ / h and held for 3 days.
[0054] Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick.
[0055] Example 3
[0056] Step (1): Add grade 1 hard clay material and high-quality clay powder with a mass fraction ratio of 1:1 to a ball mill at 650 rpm, and ball mill for 3.5 hours. Then pass the mixture through a 200-mesh sieve to obtain the mixture.
[0057] Step (2): Add 30 parts of microporous mullite aggregate and 25 parts of mixture to 21 parts of water and premix for 0.5 to 1 hour. Add 10 parts of copper-aluminum-alumina composite porous material, 10 parts of modified silica powder and 4 parts of epoxy resin and continue mixing for 2 hours. After mixing evenly, pour into the mold.
[0058] Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 4.5 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 24 hours to cure it and obtain the blank tin bath bottom brick.
[0059] Step (4): Place the blank tin bath bottom bricks in the drying kiln. In the first stage, the temperature is increased from room temperature to 200℃ at a rate of 4℃ / h and held for 1.5 days. In the second stage, the temperature is increased from 200℃ to 600℃ at a rate of 15℃ / h and held for 2 days. In the third stage, the temperature is increased from 600℃ to 950℃ at a rate of 15℃ / h and held for 2 days. In the fourth stage, the temperature is increased from 950℃ to 1450℃ at a rate of 3℃ / h and held for 3 days.
[0060] Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick.
[0061] Example 4
[0062] Step (1): Add grade 1 hard clay material and high-quality clay powder with a mass fraction ratio of 1:1 to a ball mill at 650 rpm, and ball mill for 4 hours. Then pass the mixture through a 200-mesh sieve to obtain the mixture.
[0063] Step (2): Add 20 parts of water to 30 parts of microporous mullite aggregate and 29 parts of mixture and premix for 0.5 hours. Add 10 parts of copper-aluminum-alumina composite porous material, 10 parts of modified silica powder and 1 part of epoxy resin and amino resin and continue mixing for 2 hours. After mixing evenly, pour into the mold.
[0064] Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 4 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 24 hours to cure it and obtain the blank tin bath bottom brick.
[0065] Step (4): Place the blank tin bath bottom bricks in the drying kiln. In the first stage, the temperature is increased from room temperature to 200℃ at a rate of 4℃ / h and held for 1.5 days. In the second stage, the temperature is increased from 200℃ to 600℃ at a rate of 15℃ / h and held for 2 days. In the third stage, the temperature is increased from 600℃ to 950℃ at a rate of 15℃ / h and held for 2 days. In the fourth stage, the temperature is increased from 950℃ to 1450℃ at a rate of 3℃ / h and held for 3 days.
[0066] Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick.
[0067] Example 5
[0068] Step (1): Add grade 1 hard clay material and high-quality clay powder with a mass fraction ratio of 1:1 to a ball mill at 650 rpm, and ball mill for 4 hours. Then pass the mixture through a 200-mesh sieve to obtain the mixture.
[0069] Step (2): Add 33 parts of microporous mullite aggregate and 21 parts of mixed material to 21 parts of water and premix for 1 hour. Add 10 parts of copper-aluminum-alumina composite porous material, 10 parts of modified silica powder and 5 parts of epoxy resin and amino resin and continue mixing for 2 hours. After mixing evenly, pour into the mold.
[0070] Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 5 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 24 hours to cure it and obtain the blank tin bath bottom brick.
[0071] Step (4): Place the blank tin bath bottom bricks in the drying kiln. In the first stage, the temperature is increased from room temperature to 220℃ at a rate of 5℃ / h and held for 1.5 days. In the second stage, the temperature is increased from 220℃ to 600℃ at a rate of 15℃ / h and held for 2 days. In the third stage, the temperature is increased from 600℃ to 1050℃ at a rate of 15℃ / h and held for 3 days. In the fourth stage, the temperature is increased from 1050℃ to 1450℃ at a rate of 5℃ / h and held for 3 days.
[0072] Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick.
[0073] Comparative Example 1
[0074] The difference between this comparative example and Example 1 is that the copper-aluminum-alumina composite porous material is replaced with alumina, while the rest of the preparation steps are the same as in Example 1.
[0075] Comparative Example 2
[0076] The difference between this comparative example and Example 1 is that the modified silicon powder is replaced with silicon powder, while the rest of the preparation steps are the same as in Example 1.
[0077] Performance testing
[0078] The compressive strength was tested according to GB / T 5072-2023 Test Method for Compressive Strength of Refractory Materials at Room Temperature;
[0079] Hydrogen diffusion rate was tested according to "JC / T 926-2003 Tin bath bottom bricks for float glass furnaces";
[0080] Apparent porosity and bulk density were tested according to GB / T2997-2000 Test Method for Bulk Density and Apparent Porosity of Dense Shaped Refractory Products;
[0081] The thermal expansion coefficient was tested according to GB / T7320.1-2000 Test Method for Thermal Expansion of Refractory Products;
[0082] The test results are shown in Table 1.
[0083] Table 1
[0084]
[0085] As shown in the table above, the tin bath bottom bricks prepared in Examples 1-5 have a compressive strength between 79 and 85 MPa, a hydrogen diffusivity between 35 and 37 mmH2O, an apparent porosity between 29 and 33%, and a bulk density between 2.79 and 3.01 g / cm³. 3 Between these values, the coefficient of thermal expansion is -0.1 to 0.21 at 100℃ x 5H, and the thermal conductivity is between 0.49 and 0.72 W / (m·K).
[0086] In summary, the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any changes, modifications, and evolutions made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content shall be considered equivalent embodiments of the present invention. Furthermore, any changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention shall still fall within the protection scope of the present invention.
Claims
1. A method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing, characterized in that, Includes the following steps: Step (1): Add the first-grade hard clay and high-quality clay powder into a ball mill, mill for 3-4 hours, and sieve to obtain a mixture; Step (2): Add water to the microporous mullite aggregate and the mixture and premix for 0.5 to 1 hour. Add copper-aluminum-alumina composite porous material, modified silica powder and additives and continue mixing for 1 to 2 hours. After mixing evenly, pour into the mold. Step (3): Place the blank with the mold in an 80°C blower dryer, dry and solidify for 4-5 hours, then demold it. After demolding, place the blank in a ventilated and cool place for 20-24 hours to obtain the blank tin bath bottom brick. Step (4): Place the blank tin bath bottom bricks in the drying kiln. In the first stage, raise the temperature from room temperature to 200-250℃ at a rate of 3-5℃ / h and hold for 1-1.5 days. In the second stage, raise the temperature from 200-250℃ to 550-600℃ at a rate of 10-15℃ / h and hold for 1-2 days. In the third stage, raise the temperature from 550-600℃ to 950-1050℃ at a rate of 10-15℃ / h and hold for 2-3 days. In the fourth stage, raise the temperature from 950-1050℃ to 1400-1450℃ at a rate of 3-5℃ / h and hold for 2-3 days. Step (5): Cool the sintered blank tin bath bottom brick to room temperature, and then cut and polish it according to the required shape and size to obtain the finished tin bath bottom brick; By weight: 30-40 parts of microporous mullite aggregate; 10-15 parts of copper-aluminum-alumina composite porous material; 10-15 parts of modified silica powder; 20-30 parts of the mixture; Additives 1 to 10 parts; 20-30 parts water.
2. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The ball mill speed is 650 rpm, and the ratio of balls:material:water is 2:3:
2.
3. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The sieve mesh size is 200 mesh.
4. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The preparation steps of the copper-aluminum-alumina composite porous material are as follows: weigh 35 parts of 200-mesh electrolytic copper powder, 25 parts of 250-mesh aluminum powder, 25 parts of alumina fiber and 10 parts of 100-mesh industrial salt, mix them evenly, put them into a mold, press them into shape, then calcine them at 1200℃ for 20-24 hours, cool them to room temperature, and crush them into particles with an average particle size of 250μm, and set them aside for use.
5. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The microporous mullite aggregate contains 72-77% Al2O3 and 23-29% SiO2.
6. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The copper-aluminum-alumina composite porous material contains 55-60% Cu, 8-10% Al, and 15-20% Al2O3.
7. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The preparation steps of the modified silicon micropowder are as follows: Step (a): Soak silicon carbide in a 10% dilute hydrochloric acid solution for 30 minutes, filter, and then dry in a 120°C blower dryer for 2 to 2.5 hours to remove metal impurities and moisture interference; Step (b): The cleaned silicon carbide is added to a vertical ball mill at a speed of 200 rpm and pulverized into 500-mesh silicon carbide powder at a ball:material ratio of 8:
1. Step (c): Dissolve 500 mg of tetraethyl orthosilicate in 10 ml of ethanol, add 2-3 drops of hydrochloric acid, and then stir until a stable sol is formed. Then add silane coupling agent KH-550 to it, and use the dip-coating method to bring silicon carbide particles into contact with the silicon sol to deposit a silicon-based thin film on the surface of silicon carbide. Step (d): After coating, the residual solvent is removed by blowing air and then calcined at 650°C in a nitrogen atmosphere for 8-10 hours to promote the crystallization of the silicon-based material into a stable form. After cooling, it is placed for later use.
8. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The additive is one or more of epoxy resin and amino resin.
9. The method for preparing low thermal conductivity, low iron tin bath bottom bricks by isostatic pressing according to claim 1, characterized in that, The mass fraction ratio of primary hard clay to high-quality clay powder in the mixture is 1:1.