Biomass-containing low-carbon aluminum carbon material and preparation method thereof

Abstract

The present application relates to a kind of biomass-containing low-carbon aluminum carbon material and its preparation method, belong to refractory field.The material includes the following raw materials: 65 corundum granular material, 18-20 corundum fine powder, 7-9 alumina micro powder, 2-5 silicon powder, 2-4 biomass, 1 boron carbide, and 3-4% of the total mass of the above-mentioned raw materials phenolic resin.Production method is: corundum fine powder, alumina micro powder, silicon powder, boron carbide are mixed to obtain premixed powder;Corundum granular material is mixed with part of phenolic resin to obtain premixed corundum aggregate;Biomass is added to the premixed corundum aggregate, then add premixed powder, mix the remaining phenolic resin to obtain mixture;After pressing and drying, carbon heat treatment is buried to obtain aluminum carbon refractory material.The method has the advantages of simple process, short preparation period, low production cost, low carbon content, excellent performance, etc., and is suitable for large-scale production and application.

Description

Technical Field

[0001] This invention belongs to the field of refractory material preparation technology, and relates to a low-carbon aluminum-carbon material containing biomass and its preparation method. Background Technology

[0002] Due to their excellent high-temperature mechanical properties, slag erosion resistance, and thermal shock resistance, aluminum-carbon refractories are often used as functional refractory components, such as the "three major components" of continuous casting (long nozzle, submerged nozzle, integral stopper rod), sliding plate, and temperature measuring protective sleeve. However, traditional high-carbon aluminum-carbon refractories have many drawbacks, such as: high graphite content pollutes molten steel and is not conducive to clean steel smelting; carbon in high-carbon materials oxidizes at high temperatures, resulting in a loose structure, thereby reducing its high-temperature performance, service life, and safety reliability; carbon oxidation releases a large amount of CO2 gas, polluting the environment. Therefore, it is very urgent to reduce the carbon content of aluminum-carbon materials without reducing their high-temperature performance, which is also a technical problem in this field. In recent years, there have been two main measures in the preparation technology of low-carbon refractories: (1) replacing graphite with the addition of nano carbon sources (nano carbon black, nano graphite, carbon nanofibers, and nanotubes, etc.) to reduce the carbon content. The small size of nano carbon is mainly used, which plays a role in toughening and filling when reducing the carbon content, thereby ensuring that the key properties of the material, such as thermal shock resistance and erosion resistance, are not reduced. However, nano-carbon is expensive, easily agglomerates and is difficult to disperse evenly in materials, and is more easily oxidized. Therefore, this technology still has many problems. (2) Introduce non-oxides to replace carbon in carbon-containing materials to prepare low-carbon refractory materials. Using external non-oxides such as SiC and SiAlON and in-situ generated non-oxides, compared with external non-oxides, in-situ generated non-oxides are evenly distributed in materials, often forming whiskers, and have a better strengthening and toughening effect. However, the generation temperature, generation amount, morphology, etc. of non-oxides are closely related to the carbon source. At present, graphite is commonly used as the carbon source in aluminum-carbon materials. Graphite has good crystallization and relatively low activity. The temperature at which it reacts with Si to generate SiC is high, and the reserves of graphite are limited. The preparation process is energy-intensive and polluting. Summary of the Invention

[0003] The purpose of this invention is to provide a low-carbon aluminum-carbon material containing biomass and its preparation method. By introducing biomass into the aluminum-carbon material, a low-carbon aluminum-carbon material with in-situ non-oxide whisker bonding is formed after high-temperature calcination.

[0004] This invention creatively introduces biomass to replace graphite in the preparation of novel low-carbon aluminum-carbon materials. Biomass (such as rice husks and wheat straw) is agricultural waste, inexpensive, readily available, and renewable. Some biomass can simultaneously provide both carbon and silicon sources for the material. Biomass contains amorphous carbon or amorphous carbon and amorphous SiO2, possessing a well-developed porous structure, high activity, and a large specific surface area. Amorphous carbon readily reacts with Si to form SiC whiskers. Amorphous SiO2 in biomass can also react with carbon to form SiC whiskers. Furthermore, micro-impurities in biomass can catalyze the reaction to form SiC whiskers, thereby improving the material's performance. The low-carbon aluminum-carbon materials prepared by this method exhibit superior performance, have a simple preparation process, and low production costs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-carbon aluminum-carbon material containing biomass comprises the following raw materials: 65 parts corundum granules, 18-20 parts corundum fine powder, 7-9 parts alumina micro powder, 2-5 parts silicon powder, 2-4 parts biomass, 1 part boron carbide, and 3-4% phenolic resin binder accounting for the total mass of the above raw materials.

[0006] Furthermore, the corundum particles are one or more of tabular corundum, brown corundum, white corundum, and dense corundum, with a particle size of 0-3 mm and an Al2O3 content of ≥99.9 wt%.

[0007] Furthermore, the fine corundum powder is one or more of tabular corundum, brown corundum, white corundum, and dense corundum, with a particle size ≤74μm and an Al2O3 content ≥99.9wt%.

[0008] Furthermore, the particle size of the alumina micro powder is ≤1μm.

[0009] Furthermore, the particle size of the silicon powder is ≤15μm.

[0010] Furthermore, the biomass is one or more of rice husks, wheat straw, corn cobs, peanut shells, and fruit shells.

[0011] Furthermore, the particle size of the biomass is ≤15μm.

[0012] A method for preparing a low-carbon aluminum-carbon material containing biomass includes the following steps: (1) Mix fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the proportion to obtain a premixed powder; (2) Roller milling of corundum particles of different sizes, then add 1 / 3 phenolic resin and mix for 10 minutes to obtain premixed corundum aggregate. (3) Introduce biomass into premixed corundum aggregate and mix for 20 minutes to coat the surface of corundum particles with biomass; then add the premixed powder obtained in step (1) to the biomass-coated corundum aggregate obtained in step (3), add 2 / 3 phenolic resin, and knead for 60 minutes to obtain a mixture. (4) The mixture obtained in step (3) is placed in a constant temperature and humidity environment of 25°C and 65% for 30-36 hours, and then pressed into shape at 250MPa; after molding, the material is dried at 100°C for 4 hours, 150°C for 6 hours and 180°C for 36 hours. (5) Place the dried blank in a high-temperature furnace and heat-treat it at 1400-1600℃ for 2-4 hours under carbon embedding conditions to obtain a low-carbon aluminum-carbon material containing biomass.

[0013] Further, in step (5), the heating regime is as follows: from room temperature to 600℃ in 180 minutes and keep warm for 1 hour; from 600℃ to 1000℃ in 200 minutes and keep warm for 2 hours; from 1000℃ to the target temperature in 200 minutes and keep warm for 2-4 hours.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention prepares low-carbon aluminum-carbon materials by using alumina aggregate, alumina fine powder, alumina micro powder, biomass, boron carbide and binder as raw materials and following the operating method. Under the condition of reduced carbon content (≤4%), low-carbon aluminum-carbon materials with excellent thermal shock resistance, corrosion resistance and oxidation resistance are obtained.

[0015] 2. The biomass-containing low-carbon aluminum-carbon material prepared by this invention generates a large amount of SiCw, with well-developed and uniformly distributed whiskers; compared with existing low-carbon aluminum-carbon materials, it has better room temperature mechanical properties, high temperature mechanical properties, slag resistance, thermal shock resistance and oxidation resistance.

[0016] 3. This invention provides an application approach for biomass in the field of functional refractory materials. While replacing the traditional carbon source graphite, it improves the performance of low-carbon aluminum-carbon materials, providing a new approach for the high-value utilization of biomass. Attached Figure Description

[0017] Figure 1 The X-ray diffraction pattern of the low-carbon aluminum-carbon material containing biomass prepared in Example 1 of this invention; Figure 2 A scanning electron microscope image of the surface structure of the low-carbon aluminum-carbon material containing biomass prepared in Example 1 of the present invention; Figure 3 for Figure 2 A magnified view of a portion of the image. Detailed Implementation

[0018] The technical solution and effects of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0019] In the following examples, all raw materials were purchased from the market, and except for biomass, the purity of all materials was not less than 99%. Example 1

[0020] A low-carbon aluminum-carbon material containing biomass comprises the following raw materials in parts by weight: 65 parts white fused alumina granules, 18 parts brown fused alumina fine powder, 9 parts alumina micro powder, 5 parts silica powder, 2 parts rice husk, 1 part boron carbide, and 3% phenolic resin accounting for the total mass of the above raw materials. Its preparation method is as follows: Step 1: Mix the fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the formula to obtain a premixed powder; Step 2: Roll the corundum particles of different sizes together, then add 1 / 3 phenolic resin and mix for 10 minutes to obtain premixed corundum aggregate. Step 3: Introduce rice husks into the premixed corundum aggregate and mix for 20 minutes to coat the surface of the corundum particles with biomass; then add the premixed powder obtained in Step 1 to the biomass-coated corundum aggregate obtained in Step 3, add 2 / 3 phenolic resin, and mix for 60 minutes to obtain the mixture. Step 4: Place the mixture obtained in Step 3 in a constant temperature and humidity environment of 25℃ and 65% for 30 hours, and then press it into shape at 250MPa; after molding, the material is dried at 100℃ for 4 hours, 150℃ for 6 hours and 180℃ for 36 hours. Step 5: The green body obtained in Step 4 is heat-treated at 1400℃ for 3 hours under carbon embedding conditions to obtain a low-carbon aluminum-carbon material containing biomass. The heating regime is as follows: 180 minutes to 600℃ from room temperature and hold for 1 hour; 200 minutes to 1000℃ from 600℃ and hold for 2 hours; 200 minutes to 1400℃ from 1000℃ and hold for 3 hours.

[0021] The low-carbon aluminum-carbon material containing biomass obtained in this embodiment has a room temperature flexural strength of 25.0 MPa, a high temperature flexural strength of 12.5 MPa, and a residual strength after thermal shock of 20.5 MPa. Example 2

[0022] A low-carbon aluminum-carbon material containing biomass comprises the following raw materials in parts by weight: 65 parts of tabular corundum granules, 19 parts of tabular corundum fine powder, 8 parts of alumina micro powder, 3 parts of silica powder, 2 parts of rice husk, 2 parts of wheat straw, 1 part of boron carbide, and 3% of the total mass of the above raw materials as phenolic resin. The preparation method is as follows: Step 1: Mix the fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the formula to obtain a premixed powder; Step 2: Roll the corundum particles of different sizes together, then add 1 / 3 phenolic resin and mix for 10 minutes to obtain premixed corundum aggregate. Step 3: Introduce rice husks and wheat straw into the premixed corundum aggregate and mix for 20 minutes to coat the surface of the corundum particles with biomass; then add the premixed powder obtained in Step 1 to the biomass-coated corundum aggregate obtained in Step 3, add 2 / 3 phenolic resin, and knead for 60 minutes to obtain the mixture; Step 4: Place the mixture obtained in Step 3 in a constant temperature and humidity environment of 25℃ and 65% for 32 hours, and then press it into shape at 250MPa; after molding, the material is dried at 100℃ for 4 hours, 150℃ for 6 hours and 180℃ for 36 hours. Step 5: The green body obtained in Step 4 is heat-treated at 1600℃ for 3 hours under carbon embedding conditions to obtain a low-carbon aluminum-carbon material containing biomass. The heating regime is as follows: 600℃ from room temperature in 180 minutes and held for 1 hour; 1000℃ from 600℃ to 1000℃ in 200 minutes and held for 2 hours; 1600℃ from 1000℃ to 1600℃ in 200 minutes and held for 3 hours.

[0023] The low-carbon aluminum-carbon material containing biomass obtained in this embodiment has a room temperature flexural strength of 26.0 MPa, a high temperature flexural strength of 12.3 MPa, and a residual strength of 22.3 MPa after thermal shock. Example 3

[0024] A low-carbon aluminum-carbon material containing biomass comprises the following raw materials in parts by weight: 65 parts of dense corundum granules, 20 parts of white corundum fine powder, 7 parts of alumina micro powder, 5 parts of silicon powder, 1 part of corn cob, 1 part of peanut shell, 1 part of boron carbide, and 3% of the total mass of the above raw materials as phenolic resin. The preparation method is as follows: Step 1: Mix the fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the formula to obtain a premixed powder; Step 2: Roll the corundum particles of different sizes together, then add 1 / 3 phenolic resin and mix for 10 minutes to obtain premixed corundum aggregate. Step 3: Introduce corn cobs and peanut shells into the premixed corundum aggregate and mix for 20 minutes to coat the surface of the corundum particles with biomass; then add the premixed powder obtained in Step 1 to the biomass-coated corundum aggregate obtained in Step 3, add 2 / 3 phenolic resin, and mix for 60 minutes to obtain the mixture. Step 4: Place the mixture obtained in Step 3 in a constant temperature and humidity environment of 25℃ and 65% for 33 hours, and then press it into shape at 250MPa; after molding, the material is dried at 100℃ for 4 hours, 150℃ for 6 hours and 180℃ for 36 hours. Step 5: The green body obtained in Step 4 is heat-treated at 1600℃ for 4 hours under carbon embedding conditions to obtain a low-carbon aluminum-carbon material containing biomass. The heating regime is as follows: 180 minutes to 600℃ from room temperature and hold for 1 hour; 200 minutes to 1000℃ from 600℃ and hold for 2 hours; 200 minutes to 1600℃ from 1000℃ and hold for 4 hours.

[0025] The low-carbon aluminum-carbon material containing biomass obtained in this embodiment has a room temperature flexural strength of 28.3 MPa, a high temperature flexural strength of 15.6 MPa, and a residual strength after thermal shock of 23.1 MPa. Example 4

[0026] A low-carbon aluminum-carbon material containing biomass comprises the following raw materials in parts by weight: 65 parts brown corundum granules, 18 parts dense corundum fine powder, 9 parts alumina micro powder, 5 parts silicon powder, 1 part peanut shell, 1 part fruit shell, 1 part boron carbide, and 3% phenolic resin accounting for the total mass of the above raw materials. Its preparation method is as follows: Step 1: Mix the fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the formula to obtain a premixed powder; Step 2: Roll the corundum particles of different sizes together, then add 1 / 3 phenolic resin and mix for 10 minutes to obtain premixed corundum aggregate. Step 3: Introduce peanut shells and fruit shells into the premixed corundum aggregate and mix for 20 minutes to coat the surface of the corundum particles with biomass; then add the premixed powder obtained in Step 1 to the biomass-coated corundum aggregate obtained in Step 3, add 2 / 3 phenolic resin, and mix for 60 minutes to obtain the mixture. Step 4: Place the mixture obtained in Step 3 in a constant temperature and humidity environment of 25℃ and 65% for 35 hours, and then press it into shape at 250MPa; after molding, the material is dried at 100℃ for 4 hours, 150℃ for 6 hours and 180℃ for 36 hours. Step 5: The green body obtained in Step 4 is heat-treated at 1450℃ for 3 hours under carbon embedding conditions to obtain a low-carbon aluminum-carbon material containing biomass. The heating regime is as follows: 180 minutes to 600℃ from room temperature and hold for 1 hour; 200 minutes to 1000℃ from 600℃ and hold for 2 hours; 200 minutes to 1450℃ from 1000℃ and hold for 3 hours.

[0027] The low-carbon aluminum-carbon material containing biomass obtained in this embodiment has a room temperature flexural strength of 23.7 MPa, a high temperature flexural strength of 11.5 MPa, and a residual strength after thermal shock of 20.5 MPa. Example 5

[0028] A low-carbon aluminum-carbon material containing biomass comprises the following raw materials in parts by weight: 65 parts of plate-shaped corundum granules, 19 parts of dense corundum fine powder, 7 parts of alumina micro powder, 5 parts of silicon powder, 1 part of corn cob, 1 part of peanut shell, 1 part of rice husk, 1 part of boron carbide, and 4% of the total mass of the above raw materials as phenolic resin. The preparation method is as follows: Step 1: Mix the fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the formula to obtain a premixed powder; Step 2: Roll the corundum particles of different sizes together, then add 1 / 3 phenolic resin and mix for 10 minutes to obtain premixed corundum aggregate. Step 3: Introduce corn cobs, peanut shells and rice husks into the premixed corundum aggregate and mix for 20 minutes to coat the surface of the corundum particles with biomass; then add the premixed powder obtained in Step 1 to the biomass-coated corundum aggregate obtained in Step 3, add 2 / 3 phenolic resin, and knead for 60 minutes to obtain the mixture. Step 4: Place the mixture obtained in Step 3 in a constant temperature and humidity environment of 25℃ and 65% for 36 hours, and then press it into shape at 250MPa; after molding, the material is dried at 100℃ for 4 hours, 150℃ for 6 hours and 180℃ for 36 hours. Step 5: The green body obtained in Step 4 is heat-treated at 1600℃ for 2 hours under carbon embedding conditions to obtain a low-carbon aluminum-carbon material containing biomass. The heating regime is as follows: 180 minutes to 600℃ from room temperature and hold for 1 hour; 200 minutes to 1000℃ from 600℃ and hold for 2 hours; 200 minutes to 1600℃ from 1000℃ and hold for 2 hours.

[0029] The low-carbon aluminum-carbon material containing biomass obtained in this embodiment has a room temperature flexural strength of 27.2 MPa, a high temperature flexural strength of 12.3 MPa, and a residual strength after thermal shock of 21.8 MPa.

[0030] Please see Figure 1 This is the X-ray diffraction pattern of the biomass-containing sample in Embodiment 1 of the present invention. Figure 1 It can be seen that the main materials are corundum, graphite and β-SiC, indicating that SiC whiskers are generated in the low-carbon aluminum-carbon material containing biomass.

[0031] Please see Figure 2 and Figure 3These are scanning electron microscope (SEM) images and partial magnified views of the surface structure of the low-carbon aluminum-carbon material containing biomass in Embodiment 1 of the present invention. Figure 2 and Figure 3 It can be seen that the β-SiC whiskers growing inside the sample are well-developed and uniformly distributed, forming an intricate and continuous network structure. Most of these whiskers grow in situ on the matrix and aggregate, connecting them and acting as a "bridging" mechanism. This hinders crack propagation and improves the material's strength, toughness, and thermal shock resistance. Under oxidizing conditions, a large number of surface SiC whiskers oxidize, forming a dense mullite phase with Al2O3 in the aggregate and matrix. This phase inhibits the oxidation of internal C and SiC whiskers, improving the material's oxidation resistance.

[0032] In summary, the biomass-containing low-carbon aluminum-carbon material prepared by this invention has at least the following advantages: by using biomass, its performance is improved while reducing the carbon content. The whiskers formed after sintering of the biomass-containing low-carbon aluminum-carbon material are well-developed and uniformly distributed, exhibiting better room-temperature mechanical properties, high-temperature mechanical properties, slag resistance, thermal shock resistance, and oxidation resistance. Furthermore, this preparation method uses agricultural waste as a raw material, which is both inexpensive and abundant, and also provides a new approach for the high-value utilization of agricultural waste.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. The application of biomass in the preparation of low-carbon aluminum-carbon materials, characterized in that, The biomass is corn cobs and peanut shells; The raw materials used to prepare low-carbon aluminum-carbon materials include, by mass, 65 parts of dense corundum granules, 20 parts of white corundum fine powder, 7 parts of alumina micro powder, 5 parts of silicon powder, 1 part of corn cob, 1 part of peanut shell, 1 part of boron carbide, and 3% of the total mass of the above raw materials as phenolic resin. Among them, the particle size of dense corundum granules is 0-3mm, the particle size of white corundum fine powder is ≤74μm, the particle size of alumina micro powder is ≤1μm, the particle size of silicon powder is ≤15μm, and the particle size of corn cob and peanut shell is ≤15μm. The application specifically includes the following steps: (1) Mix fine corundum powder, micro alumina powder, silicon powder and boron carbide evenly according to the proportion to obtain a premixed powder; (2) Roll the corundum particles of different sizes, then add 1 / 3 of the total amount of phenolic resin binder, mix for 10 minutes to obtain premixed corundum aggregate. (3) Introduce biomass into premixed corundum aggregate and mix for 20 minutes to coat the surface of corundum particles with biomass; then add the premixed powder obtained in step (1) to the biomass-coated corundum aggregate obtained in step (3), add 2 / 3 of the total amount of phenolic resin binder, mix for 60 minutes to obtain the mixture. (4) The mixture obtained in step (3) is placed in a constant temperature and humidity environment of 25°C and 65% for 33 hours and then pressed into shape at 250MPa; after molding, the material is dried at 100°C for 4 hours, 150°C for 6 hours and 180°C for 36 hours in sequence. (5) The dried billet is placed in a high-temperature furnace and heat-treated under carbon-embedded conditions. The heat treatment process is as follows: The temperature was raised from room temperature to 600°C in 180 minutes and maintained at that temperature for 1 hour. The temperature was raised from 600℃ to 1000℃ in 200 minutes and held for 2 hours. A low-carbon aluminum-carbon material containing biomass was prepared by raising the temperature from 1000℃ to the target temperature of 1600℃ in 200 minutes and holding it at the target temperature for 4 hours. The low-carbon aluminum-carbon material prepared using biomass has a room temperature flexural strength of 28.3 MPa, a high temperature flexural strength of 15.6 MPa, and a residual strength of 23.1 MPa after thermal shock.

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