A long-life large precast block for dry quenching coke oven and a method for manufacturing the same

Abstract

This invention discloses a method for preparing long-life large precast blocks for dry-quenching coke ovens. The precast block includes a first block and a second block that are spliced ​​together. The first block faces the inside of the coke oven, and the second block faces the outside of the coke oven. The first block has a protrusion, and the second block has a groove that matches the protrusion. This invention can be configured to meet different requirements inside and outside the oven. By utilizing the combination of raw materials and the interlocking structure of the first and second blocks, it can facilitate the absorption of heat and pressure, and significantly improve the service life compared to bricks made of single materials.

Description

Technical Field

[0001] This invention relates to the field of preform technology for dry quenching coke ovens, specifically to a long-life large preform for dry quenching coke ovens and its preparation method. Background Technology

[0002] A dry quenching coke oven is a coking process device used to process red-hot coke produced during the coking process. The basic principle of dry quenching is to cool the red-hot coke by exchanging heat with gas within the oven. In this process, the red-hot coke is loaded from the top of the oven, and low-temperature inert gas is blown into the red-hot coke layer in the cooling section by a circulating fan. After absorbing heat from the red-hot coke, the heated inert gas exits through the annular flue of the oven and then enters the waste heat boiler for heat exchange, generating steam for power generation or as a steam source for steel plants. The cooled inert gas is then blown back into the oven by the circulating fan, achieving a closed-loop cycle.

[0003] Precast blocks for dry-quenching coke ovens are typically made from high-grade refractory materials through processes such as molding, drying, and calcination to withstand high temperatures and abrasion. According to existing technical data, the refractory materials used in dry-quenching coke ovens also have some drawbacks. For example, some materials (such as mullite bricks) are prone to oxidation at high temperatures and are not suitable for use in oxidizing atmospheres. Furthermore, some currently used refractory materials, such as mullite-silicon carbide bricks, may not have sufficiently stable flexural strength and thermal shock resistance, resulting in a need to improve their service life. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a long-life large precast block for dry quenching coke ovens and its preparation method.

[0005] A long-life large precast block for dry quenching coke ovens, the precast block comprising a first block and a second block joined together, the first block facing the inside of the coke oven and the second block facing the outside of the coke oven; the mass ratio of the first block to the second block is 1:1 to 1.5, the first block is provided with a protrusion, and the second block is provided with a groove matching the protrusion;

[0006] By weight, the raw materials of the first block include: 25-40 parts Al2O3, 18-25 parts SiC, 10-15 parts mullite, and 5-7 parts aluminum silicate modified fiber; the raw materials of the second block include: 20-30 parts kaolin, 10-15 parts silicate cement, 10-15 parts diatomite, and 3-5 parts heat-resistant steel fiber.

[0007] Explanation: By distinguishing between the first and second blocks, different settings can be made for different requirements inside and outside the furnace. In addition to heat resistance, the raw materials facing the furnace also need to enhance their stability and erosion resistance. For example, alumina and mullite have good refractoriness and erosion resistance, while aluminosilicate modified fibers can improve the material's oxidation resistance, thermal shock resistance, and heat insulation performance. On the other hand, the raw materials facing outside the furnace need certain heat insulation performance and mechanical strength. For example, silicate cement can improve the mechanical strength of the precast blocks, and diatomaceous earth can improve the heat insulation effect. By using the above-mentioned material combination and the interlocking of the first and second blocks, it is beneficial to absorb heat and pressure, and compared with single-material bricks, its service life can be significantly improved.

[0008] This invention provides a method for preparing long-life large precast blocks for dry quenching coke ovens, comprising the following steps:

[0009] S1. Mix the raw materials of the first block and add yttrium oxide accounting for 0.5-1 wt% of the total weight of the raw materials of the first block. Then put it into a ball mill and add water accounting for 20-25 wt% of the total weight of the raw materials of the first block. Wet mill for 2-4 hours. After wet milling, dry at 100-150°C for 1-2 hours. Then granulate at a pressure of 5-10 MPa. Then mold at a pressure of 20-30 MPa to obtain the first molded block.

[0010] S2. Mix half the mass of kaolin, half the mass of diatomaceous earth, and one-third the mass of heat-resistant steel fiber in the second block raw material to form a first mixture. Put the first mixture into a ball mill, add water accounting for 10-13 wt% of the total weight of the second block raw material, wet mill for 1-2 hours, then freeze dry for 10-15 minutes, then heat to 160-170℃, and granulate at a granulation pressure of 8-10 MPa to obtain the first particles.

[0011] S3. Mix the remaining half-mass of kaolin, the remaining half-mass of diatomaceous earth, and the remaining two-thirds-mass of heat-resistant steel fiber and silicate cement from the second block raw material to form a second mixture. Then, put the second mixture into a ball mill, add water accounting for 10-13 wt% of the total weight of the second block raw material, and wet-mill for 1-2 hours. Then, dry it at 90-100℃ for 1-2 hours, and then granulate it at a granulation pressure of 4-6 MPa to obtain second particles. Lay the first particles on the lower layer and the second particles on the upper layer of the first particles, and then shape them at a molding pressure of 25-35 MPa to obtain a second molded block. The groove is located on the second particle layer.

[0012] S4. Place the second molded block into a high-temperature furnace for sintering at a temperature of 1600-1800℃. After sintering for 1-2 hours, splice the first molded block with the second molded block and continue sintering for 2-3 hours to obtain a precast block.

[0013] Explanation: The above preparation method can ensure that both the first and second blocks have superior brick performance. Adding yttrium oxide as an additive to the first raw material can further enhance its refractoriness and thermal stability, enabling it to maintain its performance even at extreme temperatures and helping to improve the service life of the furnace body. By setting parameters such as wet grinding and molding, an optimal preparation method can be provided, resulting in a first block with superior performance. By differentiating the raw materials in the second block, the different absorption and mechanical properties of the first and second mixtures can be utilized to reduce fatigue loss of materials at high temperatures and optimize the service life of the precast blocks.

[0014] Furthermore, the particle size of the wet-milled Al2O3, SiC, and mullite is 150-200 mesh, the aspect ratio of the aluminum silicate modified fiber is 10-15, and the fiber diameter of the aluminum silicate modified fiber is 10-20 μm.

[0015] Note: By comparing the particle sizes mentioned above, the first block can be fired to achieve better performance, with better heat resistance and oxidation resistance. Exceeding this range may alter the strength and other properties of the brick, potentially reducing its performance and lifespan.

[0016] Furthermore, in S2 and S3, the particle size of the wet-milled kaolin, silicate cement, and diatomaceous earth is 100-200 mesh, and the diameter of the heat-resistant steel fiber is 2-10 μm and the length is 3-6 mm.

[0017] Note: The above particle size setting can optimize the material properties of the second block. Exceeding this range may cause changes in the mechanical strength of the brick, making it unsuitable for long-term use.

[0018] Furthermore, in step S2, the freeze-drying temperature is -40 to -20°C.

[0019] Furthermore, the angle between the side of the protrusion and the upper surface of the first block is 20 to 45°.

[0020] Note: The above angle setting is preferred. Due to the impact of heat radiation and gas pressure, this angle has a better bonding effect. If a right angle is used directly, the contact area between the first block and the second block is reduced, which may result in poor absorption of pressure and heat radiation, thus affecting the service life of the precast block.

[0021] Furthermore, the modified aluminum silicate fiber is obtained by nano-reinforcing aluminum silicate fiber with nano-aluminum titanate.

[0022] Note: Aluminum titanate has a unique crystal structure and excellent thermal stability, which can maintain stable performance at high temperatures. Combining aluminum titanate particles with aluminum silicate fibers can enhance the thermal stability and mechanical properties of the fibers and broaden their application range.

[0023] Furthermore, the method for preparing the aluminosilicate modified fiber includes:

[0024] S1-1. Add nano-aluminum titanate to acetone solvent and disperse by ultrasonication to form a first mixture with a nano-aluminum titanate mass fraction of 15-20%.

[0025] S1-2. Mix the first mixture with the aluminum silicate fiber at a ratio of 10ml: 2-5g at 40-80℃ to obtain the second mixture.

[0026] S1-3. Then, the second mixture is subjected to heating and evaporation treatment. The heating and evaporation treatment is as follows: at 120-150°C, it is allowed to stand until the liquid in the second mixture has completely evaporated, and then it is allowed to stand at 160-200°C for 1-2 hours to obtain aluminum silicate modified fiber.

[0027] Note: The above preparation method can composite nano-aluminum titanate particles onto aluminum silicate fibers, improving various properties of aluminum silicate fibers. Nano-reinforcement modification can enhance the thermal insulation performance of aluminum silicate fibers, and the nano-reinforced aluminum silicate fibers exhibit more stable performance under harsh environments such as high temperature and high pressure.

[0028] Furthermore, the ultrasonic dispersion has an ultrasonic frequency of 60–70 kHz and an ultrasonic duration of 5–8 min, while the mixing and stirring has a stirring speed of 200–500 rpm and a stirring time of 20–30 min.

[0029] Note: The parameters mentioned above apply to the preparation process of aluminum silicate modified fibers. Exceeding these ranges may result in poor composite effect between nano-aluminum titanate and aluminum silicate fibers, thereby affecting the performance of aluminum silicate modified fibers.

[0030] The beneficial effects of this invention are:

[0031] This invention distinguishes between the first and second blocks, allowing for different settings to accommodate different requirements inside and outside the furnace. The raw materials facing inside the furnace, in addition to heat resistance, also exhibit enhanced stability and corrosion resistance. Meanwhile, the raw materials facing outside the furnace require certain heat insulation properties and mechanical strength. By utilizing the combination of their respective raw materials and the interlocking structure of the first and second blocks, it is beneficial to absorb heat and pressure, thereby increasing the service life compared to bricks made of single materials. Attached Figure Description

[0032] Figure 1 This is a longitudinal sectional view of a prefabricated block according to an embodiment of the present invention;

[0033] In the diagram, 1 represents the first block and 2 represents the second block. Detailed Implementation

[0034] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0035] Example 1: A long-life large precast block for dry quenching coke ovens, the precast block comprising a first block and a second block joined together, the first block facing the inside of the coke oven and the second block facing the outside of the coke oven; the mass ratio of the first block to the second block is 1:1.2, the first block is provided with a protrusion, and the second block is provided with a groove matching the protrusion;

[0036] By weight, the raw materials of the first block include: 30 parts Al2O3, 20 parts SiC, 12 parts mullite, and 6 parts aluminum silicate modified fiber; the raw materials of the second block include: 25 parts kaolin, 13 parts silicate cement, 13 parts diatomaceous earth, and 4 parts heat-resistant steel fiber.

[0037] The side of the protrusion forms a 40° angle with the plane of the first block.

[0038] The modified aluminum silicate fiber is obtained by nano-reinforcing aluminum silicate fiber with nano-aluminum titanate.

[0039] The method for preparing the aluminosilicate modified fiber includes:

[0040] S1-1. Nano aluminum titanate is added to acetone solvent and dispersed by ultrasonication. The ultrasonic dispersion frequency is 65kHz and the ultrasonic time is 7min, forming a first mixture with a nano aluminum titanate mass fraction of 17%.

[0041] S1-2. At a ratio of 10ml:4g, the first mixture is mixed and stirred with aluminum silicate fiber at 60℃. The stirring speed is 300rpm and the stirring time is 25min to obtain the second mixture.

[0042] S1-3. Then, the second mixture is subjected to heating and evaporation treatment. The heating and evaporation treatment is as follows: at 140°C, it is allowed to stand until the liquid in the second mixture has completely evaporated, and then it is allowed to stand at 170°C for 1.5 hours to obtain aluminum silicate modified fiber.

[0043] A method for preparing long-life large precast blocks for dry quenching coke ovens includes the following steps:

[0044] S1. Mix the raw materials of the first block and add yttrium oxide accounting for 0.8 wt% of the total weight of the raw materials of the first block. Then put it into a ball mill and add water accounting for 22 wt% of the total weight of the raw materials of the first block. Wet mill for 3 hours. After wet milling, dry at 120°C for 1.5 hours. Then granulate at a pressure of 8 MPa. Then form it at a pressure of 25 MPa to obtain the first molded block. The protrusion is located on the first molded block.

[0045] The wet-milled Al2O3, SiC, and mullite have a particle size of 150-200 mesh, the aluminum silicate modified fiber has an aspect ratio of 12, and the fiber diameter of the aluminum silicate modified fiber is 10-20 μm.

[0046] S2. Half the mass of kaolin, half the mass of diatomaceous earth, and one-third the mass of heat-resistant steel fiber from the second block raw material are mixed to form a first mixture. The first mixture is placed in a ball mill, and water accounting for 12 wt% of the total weight of the second block raw material is added. The mixture is wet-milled for 1.5 hours, then freeze-dried for 13 minutes, and then heated to 165°C for granulation. The granulation pressure is 9 MPa to obtain the first particles. In S2, the freeze-drying temperature is -30°C.

[0047] S3. Mix the remaining half-mass of kaolin, the remaining half-mass of diatomaceous earth, and the remaining two-thirds-mass of heat-resistant steel fiber and silicate cement from the second block raw material to form a second mixture. Then, put the second mixture into a ball mill, add water accounting for 12wt% of the total weight of the second block raw material, and wet grind for 1.5 hours. Then, dry at 95°C for 1.5 hours, and then granulate at a granulation pressure of 5MPa to obtain second particles. Lay the first particles on the lower layer and the second particles on the upper layer of the first particles, and then shape them at a molding pressure of 30MPa to obtain a second molded block. The groove is located on the second particle layer. The particle size of the wet-ground kaolin, silicate cement, and diatomaceous earth is 100-200 mesh, and the diameter of the heat-resistant steel fiber is 2-10μm and the length is 3-6mm.

[0048] S4. The second molded block is placed in a high-temperature furnace for sintering at a temperature of 1700℃. After sintering for 1.5 hours, the first molded block is spliced ​​with the second molded block, and then sintering continues for another 2.5 hours to obtain a precast block.

[0049] Example 2: This example differs from Example 1 in that the raw material composition is different. The mass ratio of the first block to the second block is 1:1. The raw materials of the first block include: 25 parts Al2O3, 25 parts SiC, 15 parts mullite, and 5 parts aluminum silicate modified fiber; the raw materials of the second block include: 20 parts kaolin, 15 parts silicate cement, 10 parts diatomaceous earth, and 3 parts heat-resistant steel fiber.

[0050] Example 3: This example differs from Example 1 in that the raw material composition is different. The mass ratio of the first block to the second block is 1:1.5. The raw materials of the first block include: 40 parts Al2O3, 18 parts SiC, 10 parts mullite, and 7 parts aluminum silicate modified fiber; the raw materials of the second block include: 30 parts kaolin, 10 parts silicate cement, 15 parts diatomaceous earth, and 5 parts heat-resistant steel fiber.

[0051] Example 4: This example differs from Example 1 in that the preparation parameters of the first block are different. In S1, the raw materials of the first block are mixed and 0.5 wt% of yttrium oxide is added to the raw materials of the first block. Then, the mixture is placed in a ball mill and 20 wt% of water is added to the raw materials of the first block. The mixture is wet-milled for 2 hours. After wet milling, it is dried at 150°C for 1 hour and then granulated at a pressure of 10 MPa. Finally, it is molded at a pressure of 20 MPa to obtain the first molded block.

[0052] Example 5: This example differs from Example 1 in that the preparation parameters of the first block are different. In S1, the raw materials of the first block are mixed and yttrium oxide accounting for 1 wt% of the raw materials of the first block is added. Then, the mixture is placed in a ball mill and water accounting for 25 wt% of the raw materials of the first block is added. The mixture is wet-milled for 4 hours. After wet milling, the mixture is dried at 100°C for 2 hours and then granulated at a pressure of 5 MPa. Finally, the mixture is molded at a pressure of 30 MPa to obtain the first molded block.

[0053] Example 6: This example differs from Example 1 in that, in S2, half the mass of kaolin, half the mass of diatomaceous earth, and one-third the mass of heat-resistant steel fiber from the second block raw material are mixed to form a first mixture. The first mixture is placed in a ball mill, and water accounting for 13wt% of the total weight of the second block raw material is added. The mixture is wet-milled for 2 hours, then freeze-dried for 10 minutes, and then heated to 160°C for granulation. The granulation pressure is 8MPa to obtain the first particles.

[0054] Example 7: This example differs from Example 1 in that, in S2, half the mass of kaolin, half the mass of diatomaceous earth, and one-third the mass of heat-resistant steel fiber from the second block raw material are mixed to form a first mixture. The first mixture is placed in a ball mill, and water accounting for 10 wt% of the total weight of the second block raw material is added. The mixture is wet-milled for 1 hour, then freeze-dried for 15 minutes, and then heated to 170°C for granulation. The granulation pressure is 10 MPa to obtain the first particles.

[0055] Example 8: This example differs from Example 1 in that, in S3, half the mass of kaolin, half the mass of diatomaceous earth, and two-thirds the mass of heat-resistant steel fiber and silicate cement from the second block raw material are mixed to form a second mixture. The second mixture is then placed in a ball mill, and water accounting for 13 wt% of the total weight of the second block raw material is added. The mixture is wet-milled for 1 hour, dried at 90°C for 1 hour, and then granulated at a pressure of 4 MPa to obtain second particles. The first particles are laid on the lower layer, and the second particles are laid on the upper layer of the first particles. The mixture is then molded at a pressure of 35 MPa to obtain a second molded block. The groove is located on the second particle layer.

[0056] Example 9: This example differs from Example 1 in that, in S3, half the mass of kaolin, half the mass of diatomaceous earth, and two-thirds the mass of heat-resistant steel fiber and silicate cement from the second block raw material are mixed to form a second mixture. The second mixture is then placed in a ball mill, and water accounting for 10 wt% of the total weight of the second block raw material is added. The mixture is wet-milled for 2 hours, dried at 100°C for 2 hours, and then granulated at a pressure of 6 MPa to obtain second particles. The first particles are laid on the lower layer, and the second particles are laid on the upper layer of the first particles. The mixture is then molded at a pressure of 25 MPa to obtain a second molded block. The groove is located on the second particle layer.

[0057] Example 10: The difference between this example and Example 1 is that in S4, the second molding block is placed in a high-temperature furnace for sintering at a temperature of 1800°C. After sintering for 1 hour, the first molding block and the second molding block are spliced ​​together, and then sintering continues for 2 hours to obtain a preformed block.

[0058] Example 11: The difference between this example and Example 1 is that in S4, the second molding block is placed in a high-temperature furnace for sintering at a sintering temperature of 1600°C. After sintering for 2 hours, the first molding block and the second molding block are spliced ​​together, and then sintering continues for 3 hours to obtain a preformed block.

[0059] Example 12: This example differs from Example 1 in that, in S2, the freeze-drying temperature is -20°C.

[0060] Example 13: This example differs from Example 1 in that, in S2, the freeze-drying temperature is -40°C.

[0061] Example 14: This example differs from Example 1 in that the preparation parameters of the aluminosilicate modified fiber are different.

[0062] S1-1. Take nano aluminum titanate, add nano aluminum titanate to acetone solvent, and disperse by ultrasonication. The ultrasonic dispersion frequency is 60kHz and the ultrasonic time is 5min, forming a first mixture with a nano aluminum titanate mass fraction of 20%.

[0063] S1-2. At a ratio of 10ml:5g, the first mixture is mixed and stirred with aluminum silicate fiber at 40℃. The stirring speed is 200rpm and the stirring time is 20min to obtain the second mixture.

[0064] S1-3. Then, the second mixture is subjected to heating and evaporation treatment. The heating and evaporation treatment is as follows: at 120°C, it is allowed to stand until the liquid in the second mixture has completely evaporated, and then it is allowed to stand at 160°C for 1 hour to obtain aluminum silicate modified fiber.

[0065] Example 15: This example differs from Example 1 in that the preparation parameters of the aluminosilicate modified fiber are different.

[0066] S1-1. Take nano aluminum titanate, add nano aluminum titanate to acetone solvent, and disperse by ultrasonication. The ultrasonic dispersion frequency is 70kHz and the ultrasonic time is 8min, forming a first mixture with a nano aluminum titanate mass fraction of 15%.

[0067] S1-2. At a ratio of 10ml:2g, the first mixture is mixed and stirred with aluminum silicate fiber at 80℃. The stirring speed is 500rpm and the stirring time is 30min to obtain the second mixture.

[0068] S1-3. Then, the second mixture is subjected to heating and evaporation treatment. The heating and evaporation treatment is as follows: at 150°C, it is allowed to stand until the liquid in the second mixture has completely evaporated, and then it is allowed to stand at 200°C for 2 hours to obtain aluminum silicate modified fiber.

[0069] Example 16: This example differs from Example 1 in that the side of the protrusion is at a 20° angle to the plane of the first block.

[0070] Example 17: The difference between this example and Example 1 is that the side of the protrusion is at a 45° angle to the plane of the first block.

[0071] Experimental Example: The description of this experimental example is based on the scheme described in Example 1, and aims to illustrate the practical application effect of the present invention.

[0072] The precast blocks obtained in Examples 1 to 17 were subjected to a 1000-hour treatment at a temperature of 1300℃, a pressure of 0.5MPa, an atmosphere of 60% nitrogen + 40% oxygen, and an atmosphere wind speed of 1L / s to obtain the wear rate (the ratio of wear amount to the mass of the precast block).

[0073] The compressive strength, thermal shock resistance, and erosion index were tested and recorded at 1100℃.

[0074] Wear rate and compressive strength can well reflect the service life of precast blocks; when the wear is low and the compressive strength is maintained within a certain range, it indicates that the precast blocks have a good service life.

[0075] Experimental Example: 1. The prefabricated blocks obtained in Examples 1 to 17 were subjected to the above tests respectively. The test results are as follows:

[0076] 1. Investigate the effects of different raw material components on the performance of precast blocks;

[0077] Comparative Example 1: Using mullite as raw material, the shape of the preformed block was prepared according to Example 1, and the preparation method was prepared according to S1 in Example 1 to obtain the preformed block of Comparative Example 1;

[0078] Comparative Example 2: The raw materials of the first block and the second block in Example 1 were directly mixed and fired according to the molding and firing method of the first block to obtain a whole brick, namely the precast block of Comparative Example 2.

[0079] Comparative Example 3: The difference from Example 1 is that the aluminum silicate modified fibers in the first block are replaced with aluminum silicate fibers;

[0080] Comparative Example 4: The difference from Example 1 is that the molding method of the second block is the same as that of the first block, that is, the raw material of the second block is processed according to S1, the operation process of S2 and S3 is deleted, and then the preform of Comparative Example 4 is obtained by firing in S4.

[0081] Comparative Example 5: The difference from Example 1 is that in S4, the sintering time for both the first block and the second block is set to 2.5h.

[0082] Comparative Example 6: The difference from Example 1 is that the mass ratio of the first block to the second block is 1:1;

[0083] Comparative Example 7: The particle size of Al2O3, SiC, and mullite after wet grinding was 100-110 mesh; the particle size of kaolin, silicate cement, and diatomite after wet grinding was 50-80 mesh.

[0084] Example 1 and Comparative Examples 1 to 7 were compared, as shown in Table 1;

[0085] Table 1. Experimental results of precast block performance under different treatments

[0086]

[0087]

[0088] As can be seen from Table 1, comparing Example 1 and Comparative Example 1, it can be seen that the precast blocks obtained by the method in Example 1 have better performance in all aspects. This may be because, in Comparative Example 1, mullite as a raw material may have defects such as easy oxidation, resulting in poor performance and difficulty in coping with the application of wind and pressure, leading to greater wear. Moreover, as a raw material alone, mullite has limited compressive strength, etc. The raw material composition in Example 1 can improve the compressive strength and thermal shock resistance of the precast blocks.

[0089] Comparing Example 1 and Comparative Example 2, it can be seen that compared to Comparative Example 2, where the raw materials of the first and second blocks are directly mixed to obtain a whole brick, experiments have shown that the various properties of the brick in Comparative Example 2 are reduced. This may be because relying solely on the raw materials of Example 1 cannot fully utilize the superior properties of each material, resulting in poor brick performance. This is because during the application of heat radiation and pressure, the force on a whole brick will be concentrated inside the material. However, the differentiated arrangement in Example 1 can both utilize the material's performance based on heat conduction and allow for residual diffusion within the material, thereby improving its performance and lifespan.

[0090] Comparing Example 1 and Comparative Example 3, it can be found that, compared with Comparative Example 3 where the aluminum silicate fiber was not modified, Example 1 provides a nanoparticle improvement scheme, which has a more direct effect on improving the performance of the preform. The reason is that aluminum titanate has a unique crystal structure and excellent thermal stability. Combining aluminum titanate particles with aluminum silicate fiber can enhance the thermal stability and mechanical properties of the fiber, thereby improving the performance of the preform.

[0091] Comparing Example 1 and Comparative Example 4, it can be seen that in Example 1, using different molding and preparation methods for the first and second blocks has a good effect. In Comparative Example 4, different raw materials are treated with uniform conditions, and although the preform obtained has good overall performance, it is still inferior to Example 1 in each aspect. This may be because the raw materials of the first and second blocks are different, and the settings of S2 and S3 help the material absorb heat layer by layer, thereby reducing its overall loss.

[0092] Comparing Example 1 and Comparative Example 5, it can be seen that the sintering time in Example 1 is more preferred. This may be because the raw materials and molding parameters of the first block and the second block are different. If the sintering time of Comparative Example 5 is used for both, the second block may not be sintered completely, and its performance may not be optimal. Therefore, the method of Example 1 is better.

[0093] Comparing Example 1 with Comparative Example 6, it can be found that the quality of the first block and the second block in Example 1 is preferred; comparing Example 1 with Comparative Example 7, it can be found that the particle size of the raw material in Example 1 is preferred. This may be because the particle size in Example 1 is suitable for the direct bonding of various materials, thereby resulting in better performance.

[0094] 2. Investigate the effects of different preparation parameters on the performance of preformed blocks;

[0095] Examples 1-15 were compared, as shown in Table 2;

[0096] Table 2. Test results of preform performance under different preparation parameters

[0097] parameter Thermal shock resistance (secondary) Wear rate % Example 1 50 0.05 Example 2 48 0.07 Example 3 47 0.06 Example 6 46 0.08 Example 7 47 0.10 Example 8 48 0.06 Example 9 46 0.08 Example 12 47 0.07 Example 13 47 0.07 Example 14 48 0.05 Example 15 49 0.06

[0098] As can be seen from Table 2, comparing Examples 1, 2, and 3, the composition of Example 1 is preferred. This may be because the combination of components in Example 1 can increase the strength and wear resistance of the resulting preform. Comparing Examples 1, 6, 7, 8, and 9, the parameter settings of Example 1 are preferred for the molding and preparation process of the second block. Comparing Examples 1, 12, and 13, the freeze-drying temperature of Example 1 is more suitable, possibly because the freezing temperature in Example 1 has a better effect on the microstructure of the raw material of the first block. Comparing Examples 1, 14, and 15, the preparation parameters of the aluminosilicate modified fiber have a certain influence on the performance of the preform, and the parameters in Example 1 are preferred.

Claims

1. A long-life large precast block for dry quenching coke ovens, characterized in that, The prefabricated block includes a first block and a second block that are spliced ​​together. The first block faces the inside of the coke oven, and the second block faces the outside of the coke oven. The mass ratio of the first block to the second block is 1:1 to 1.

5. The first block is provided with a protrusion, and the second block is provided with a groove that matches the protrusion. By weight, the raw materials of the first block include: 25-40 parts Al2O3, 18-25 parts SiC, 10-15 parts mullite, and 5-7 parts aluminum silicate modified fiber; the raw materials of the second block include: 20-30 parts kaolin, 10-15 parts silicate cement, 10-15 parts diatomite, and 3-5 parts heat-resistant steel fiber. The modified aluminum silicate fiber is obtained by nano-reinforcing aluminum silicate fiber with nano-aluminum titanate. The method for preparing the long-life large precast block includes the following steps: S1. Mix the raw materials of the first block and add yttrium oxide accounting for 0.5~1wt% of the total weight of the raw materials of the first block. Then put it into a ball mill and add water accounting for 20~25wt% of the total weight of the raw materials of the first block. Wet mill for 2~4 hours. After wet milling, dry at 100~150°C for 1~2 hours. Then granulate at a pressure of 5~10MPa. Then form it at a pressure of 20~30MPa to obtain the first molded block. The protrusion is located on the first molded block. S2. Mix half the mass of kaolin, half the mass of diatomaceous earth, and one-third the mass of heat-resistant steel fiber in the second block raw material to form a first mixture. Put the first mixture into a ball mill, add water accounting for 10~13wt% of the total weight of the second block raw material, wet mill for 1~2 hours, then freeze dry for 10~15 minutes, then heat to 160~170°C, and granulate at a granulation pressure of 8~10MPa to obtain the first particles. S3. Mix the remaining half-mass of kaolin, the remaining half-mass of diatomaceous earth, and the remaining two-thirds-mass of heat-resistant steel fiber and silicate cement from the second block raw material to form a second mixture. Then, put the second mixture into a ball mill, add water accounting for 10-13 wt% of the total weight of the second block raw material, and wet grind for 1-2 hours. Then, dry at 90-100°C for 1-2 hours, and then granulate at a granulation pressure of 4-6 MPa to obtain second particles. Lay the first particles on the lower layer and the second particles on the upper layer of the first particles, and then shape them at a molding pressure of 25-35 MPa to obtain a second molded block. The groove is located on the second particle layer. S4. Place the second molded block into a high-temperature furnace for sintering at a temperature of 1600~1800°C. After sintering for 1~2 hours, splice the first molded block with the second molded block and continue sintering for 2~3 hours to obtain the preformed block.

2. The long-life large precast block for dry quenching coke ovens as described in claim 1, characterized in that, The wet-milled Al2O3, SiC, and mullite have a particle size of 150-200 mesh, the aluminum silicate modified fiber has an aspect ratio of 10-15, and the fiber diameter of the aluminum silicate modified fiber is 10-20 μm.

3. The long-life large precast block for dry quenching coke ovens as described in claim 1, characterized in that, In S2 and S3, the particle size of the wet-milled kaolin, silicate cement, and diatomaceous earth is 100-200 mesh, and the diameter of the heat-resistant steel fiber is 2-10 μm and the length is 3-6 mm.

4. A long-life large precast block for dry quenching coke ovens as described in claim 1, characterized in that, In step S2, the freeze-drying temperature is -40 to -20°C.

5. A long-life large precast block for dry quenching coke ovens as described in claim 1, characterized in that, The angle between the side of the protrusion and the upper surface of the first block is 20~45°.

6. A long-life large precast block for dry quenching coke ovens as described in claim 1, characterized in that, The method for preparing the aluminosilicate modified fiber includes: S1-1. Add nano-aluminum titanate to acetone solvent and disperse by ultrasonication to form a first mixture with a nano-aluminum titanate mass fraction of 15~20%. S1-2. Mix the first mixture with the aluminum silicate fiber at a ratio of 10ml: 2~5g at 40~80°C to obtain the second mixture. S1-3. Then, the second mixture is subjected to heating and evaporation treatment. The heating and evaporation treatment is as follows: at 120~150°C, it is allowed to stand until the liquid in the second mixture has completely evaporated, and then it is allowed to stand at 160~200°C for 1~2 hours to obtain aluminum silicate modified fiber.

7. A long-life large precast block for dry quenching coke ovens as described in claim 6, characterized in that, The ultrasonic dispersion is performed at a frequency of 60-70 kHz for 5-8 minutes, and the mixing is performed at a speed of 200-500 rpm for 20-30 minutes.

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