Multifunctional fire-resistant heat-insulating brick and manufacturing process thereof

Abstract

The invention relates to the field of fire-resistant and heat-insulating bricks, and discloses a multifunctional fire-resistant and heat-insulating brick and a manufacturing process thereof. Comprising the following raw materials in parts by weight: 10-15 parts of silicon carbide, 10-20 parts of mullite, 5-10 parts of cordierite, 30-40 parts of aluminum oxide, 5-10 parts of zirconium oxide, 2-4 parts of titanium dioxide nanoparticles, 6-9 parts of a cleaning agent, 3-5 parts of yttrium oxide and 1-12 parts of a micropore forming agent. By adding manganese oxide and cerium oxide, when the surface of the brick body is in contact with reducing substances or impurities, the oxidation reaction of the reducing substances or impurities can be promoted, and the impurities are converted into oxides which are easy to remove, so that the high-temperature oxidation self-cleaning function is realized, and the capability of keeping the brick body clean and stable in performance in a complex high-temperature environment is enhanced; brick body corrosion and performance degradation caused by impurity deposition are reduced, and therefore the problem that in a high-temperature industrial environment, dirt and impurities are prone to being attached to the surface of a traditional fire-resistant heat-insulating brick, and the heat-insulating performance of the traditional fire-resistant heat-insulating brick is affected is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory heat-insulating bricks, and specifically to a multifunctional refractory heat-insulating brick and its manufacturing process. Background Art

[0002] In the modern industrial field, refractory heat-insulating materials are key materials indispensable for many high-temperature industrial processes. From blast furnaces and converters in steel smelting, to kilns in ceramic firing, and then to furnaces in glass manufacturing, etc., the extreme environments inside these high-temperature equipment pose stringent requirements on materials. With the continuous progress of industrial technology, the performance expectations for refractory heat-insulating materials are no longer limited to simple fire resistance and heat insulation, but are developing towards the direction of multifunction, high performance, long life, and environmental friendliness.

[0003] Traditional refractory heat-insulating bricks mainly have single functions or simple composite functions. Common refractory heat-insulating bricks are mostly made of a single refractory raw material or a simple mixture of a few raw materials. In high-temperature industrial environments, dirt and impurities are likely to adhere to the surface of refractory heat-insulating bricks, affecting their heat insulation performance. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a multifunctional refractory heat-insulating brick and its manufacturing process, which solves the problem that in high-temperature industrial environments, dirt and impurities are likely to adhere to the surface of traditional refractory heat-insulating bricks, affecting their heat insulation performance.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A multifunctional refractory heat-insulating brick, comprising the following raw materials in parts by weight: 10 - 15 parts of silicon carbide, 10 - 20 parts of mullite, 5 - 10 parts of cordierite, 30 - 40 parts of alumina, 5 - 10 parts of zirconia, 2 - 4 parts of titanium dioxide nanoparticles, 6 - 9 parts of a cleaning agent, 3 - 5 parts of yttrium oxide, and 1 - 12 parts of a micropore-forming agent.

[0006] Preferably, the cleaning agent comprises manganese oxide and cerium oxide, and their ratio is 3 - 4:2 - 1 in sequence.

[0007] Preferably, the micropore-forming agent is one or a combination of more of rice husk ash, polystyrene microspheres, and graphite powder.

[0008] The manufacturing process of the multifunctional refractory heat-insulating brick comprises the following steps:

[0009] S1. Pretreatment of raw materials: Pretreat silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, the cleaning agent, yttrium oxide, and the micropore-forming agent.

[0010] S2. Raw material mixing: Mix the pre-treated silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, cleaning agent, yttrium oxide, and micropore former in proportion, and add a composite dispersant. Complete the mixing when the relative standard deviation of the absorbance of each raw material is less than 2%;

[0011] S3. Molding process: Preheat the mold through an intelligent rubber mold, then fill the mixed raw materials into the mold for preliminary compaction, and then form the preliminarily compacted mold through a cold isostatic pressing device and release the pressure after molding;

[0012] S4. Sintering process: Sinter the formed raw materials through a sintering furnace to complete the preparation.

[0013] Preferably, in step S1, the pretreatment of silicon carbide is by a jet mill with an air flow pressure of 0.5 - 0.8 MPa and a flow rate of 30 - 50 m / s, and the grinding medium is corundum balls with a diameter of 3 mm - 5 mm. Crush the particle size of silicon carbide to 5 - 15 μm;

[0014] The pretreatment of the mullite, cordierite, alumina, and zirconia is to first coarsely crush them to a particle size less than 3 mm by a jaw crusher, and then finely grind them by a planetary ball mill with a rotational speed of 400 - 600 r / min for 6 - 8 hours. Add 0.2% - 0.5% of the raw material mass of triethanolamine as a grinding aid. After grinding, sieve through multi-layer vibrating sieves of 10 μm, 20 μm, and 30 μm. The part that does not meet the particle size requirements is ball milled and sieved twice until the particle size is 10 - 30 μm and the distribution is uniform;

[0015] The pretreatment of the titanium dioxide nanoparticles is to disperse them in an isopropyl alcohol solution containing a titanate coupling agent and a photocatalytic activity enhancer, and treat them under the synergistic action of stirring at 1000 - 1500 r / min and ultrasonic waves with a frequency of 40 kHz and a power of 500 W for 2 - 3 hours. Then centrifuge at 8000 - 10000 r / min and wash with absolute ethanol 3 - 5 times. The activity improvement rate is more than 30%. The dosage of the titanate coupling agent is 3% - 6% of the particle mass, and the photocatalytic activity enhancer is silver nanoparticles with a particle size of 10 - 20 nm and a dosage of 1% - 3% of the particle mass;

[0016] The cleaner pretreatment is to separately prepare aqueous solutions of manganese nitrate and cerium nitrate with a concentration of 0.5 - 1.0 mol / L. After stirring at 600 - 800 r / min with a magnetic stirrer, 2 - 3 mol / L ammonia water is added dropwise. The reaction temperature is 40 - 60 °C, the pH value is 8 - 10. After precipitation, it is aged for 4 - 6 hours, centrifuged at 6000 - 8000 r / min with a centrifuge until the conductivity of the washing liquid is less than 50 μS / cm, dried at 100 - 120 °C for 12 - 24 hours, and then calcined at 500 - 600 °C for 3 - 5 hours to obtain a manganese oxide - cerium oxide composite powder with a particle size of 10 - 30 nm;

[0017] The microporous former pretreatment is to pre - burn rice husk ash in a high - temperature furnace at 600 - 800 °C for 2 - 3 hours, soak it in a dilute hydrochloric acid solution with a concentration of 3% - 5% and a liquid - to - solid ratio of 5:1 - 8:1 for 1 - 2 hours, then soak it in a sodium hydroxide solution with a concentration of 2% - 4% and a liquid - to - solid ratio of 4:1 - 6:1 for 1 - 2 hours. After leaching, it is rinsed with water until neutral, dried at 120 - 150 °C for 3 - 5 hours, and finally processed by a planetary ball mill to a particle size of 5 - 15 μm. The rotational speed of the planetary ball mill is 500 - 700 r / min, and the ball - milling time is 3 - 5 hours.

[0018] Preferably, in step S2, the composite dispersant includes polyethylene glycol and stearic acid, and their ratio is 2:1 - 3:1 in sequence. The addition amount of the composite dispersant is 0.8% - 1.2% of the total mass of the raw materials.

[0019] Preferably, in step S3, the heating channel of the intelligent rubber mold is spiral, with a diameter of 5 - 8 mm, a pitch of 10 - 15 mm, the power of the electric heating wire is 2 - 3 kW, the cooling uses circulating water, the flow rate of the circulating water pump is 5 - 10 L / min, the measurement range of the pressure sensor is 0 - 5 MPa, the measurement range of the flow controller for flow rate is 0 - 20 g / s, the preheating temperature is 60 - 90 °C, the pressure for filling the raw materials into the mold is 0.5 - 1.0 MPa, the speed is 5 - 10 g / s, the initial compaction is to hold the pressure at 2 - 3 MPa for 10 - 20 seconds, the forming by cold isostatic pressing equipment is to pre - press at 50 - 80 MPa for 30 - 60 seconds, then adjust the pressure rising rate and the target pressure value, and hold the pressure at 180 - 220 MPa for 2 - 3 minutes. The pressure relief rate after forming is 1 - 2 MPa / s.

[0020] Preferably, in step S4, sintering the brick blank through a sintering furnace includes the following steps:

[0021] S401. Heat the formed raw materials from room temperature to 500 - 600 °C at a rate of 3 - 5 °C / min through the sintering furnace, and at the same time introduce nitrogen. The flow rate of the nitrogen is 5 - 10 L / min, and the pressure is maintained at +0.5 kPa;

[0022] S402. Then, heat it up to 1000 - 1200 °C at a rate of 2 - 4 °C / min. Meanwhile, introduce a mixture of hydrogen and nitrogen with a flow rate of 5 - 10 L / min, and maintain the pressure at +0.3 kPa. The concentration of hydrogen is 2% - 5% of the volume ratio of the mixed gas.

[0023] S403. Then, heat it up to 1600 - 1800 °C at a rate of 1 - 3 °C / min. Meanwhile, introduce argon with a flow rate of 15 - 20 L / min, and maintain the pressure at +1 kPa.

[0024] S404. Then, reduce the flow rate of argon to 5 - 8 L / min, and maintain the pressure at +0.3 kPa until the brick cools down to below 500 °C. Then, take out the brick and let it cool naturally to room temperature to complete the sintering, thus completing the preparation.

[0025] The present invention provides a multifunctional refractory heat - insulating brick and its manufacturing process, which has the following beneficial effects:

[0026] 1. By adding manganese oxide and cerium oxide in the present invention, when the surface of the brick contacts reducing substances or impurities, it can promote their oxidation reaction, convert these impurities into oxides that are easy to remove, thereby realizing the high - temperature oxidation self - cleaning function, enhancing the ability of the brick to maintain cleanliness and performance stability in a complex high - temperature environment, reducing the corrosion and performance decline of the brick caused by impurity deposition, and thus solving the problem that in a high - temperature industrial environment, the surface of traditional refractory heat - insulating bricks is prone to attaching dirt and impurities, affecting their heat - insulating performance.

[0027] 2. By adding titanium dioxide nanoparticles in the present invention, under light illumination conditions, the photocatalytic active sites on its surface can be excited, thereby generating free radicals with strong oxidizing properties, decomposing the organic dirt attached to the surface of the brick, keeping the surface of the brick clean, and reducing problems such as the decrease in heat transfer efficiency and the deterioration of brick performance caused by dirt accumulation.

[0028] 3. The present invention provides high - quality basic materials for subsequent reactions through raw material pretreatment, makes each raw material evenly dispersed and fully contacted through raw material mixing, promotes the synergistic effect between raw materials, shapes a brick blank with uniform density and extremely few internal defects through forming treatment, and promotes the brick blank to undergo complex physical and chemical changes under ideal atmosphere and temperature conditions through sintering treatment, forming a perfect crystal structure, stable functional phases, and reasonable pore distribution, thereby endowing the refractory heat - insulating brick with excellent multifunctional properties such as wear resistance, heat insulation, and self - cleaning, and realizing the long - term stable operation of the product in a high - temperature complex environment.

[0029] 4. Through sintering treatment, nitrogen is introduced at low temperature to prevent oxidation and create an initial stable environment to ensure the chemical stability of raw materials. At medium temperature, a hydrogen-nitrogen mixed gas is introduced to promote reactions and optimize functional components, stimulating activity and potential, improving the microstructure and functional phases. At high temperature, argon is introduced to protect easily oxidized components and promote the close combination and formation of key functional phases, endowing wear resistance and self-cleaning functions to meet the stringent requirements at high temperature. During cooling, argon is controlled to avoid stress and oxidation damage to the structure, maintaining the structural integrity and continuous performance, and ensuring reliable product quality and lasting functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a process flow diagram of the manufacturing process of the multifunctional refractory heat-insulating brick proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Embodiment:

[0033] The embodiment of the present invention provides a multifunctional refractory heat-insulating brick, which includes the following raw materials in parts by weight: 10-15 parts of silicon carbide, 10-20 parts of mullite, 5-10 parts of cordierite, 30-40 parts of alumina, 5-10 parts of zirconia, 2-4 parts of titanium dioxide nanoparticles, 6-9 parts of a cleaning agent, 3-5 parts of yttrium oxide, and 1-12 parts of a microporous forming agent; the cleaning agent includes manganese oxide and cerium oxide, and their ratio is 3-4:2-1 in sequence; the microporous forming agent is one or a combination of rice husk ash, polystyrene microspheres, and graphite powder.

[0034] Specifically, by adding silicon carbide, which has the characteristics of high hardness and high strength and is evenly distributed in the brick structure, it can effectively resist the action of external forces, reduce the wear of the brick surface during high-temperature material scouring or friction, thereby achieving good wear resistance and extending the service life of the refractory heat-insulating brick under high-temperature wear-resistant working conditions.

[0035] By adding mullite, which has excellent high-temperature stability and thermal shock resistance and can maintain its own structural stability in a high-temperature environment, it enhances the overall structural stability and thermal shock resistance of the brick body, thereby achieving that in a high-temperature industrial environment with frequent thermal expansion and contraction, the brick body can still maintain good performance and reduce the risk of cracking caused by thermal stress.

[0036] By adding cordierite, due to its low coefficient of thermal expansion, a relatively small volume change occurs during temperature variations, reducing the damage to the internal structure of the brick caused by thermal expansion and contraction. This improves the thermal shock resistance of the brick, enabling the refractory insulation brick to adapt to working conditions with rapid temperature changes and ensuring the safe and stable operation of high-temperature equipment.

[0037] By adding alumina and zirconia, alumina provides a good refractory matrix, and zirconia can form a partial solid solution with alumina, thereby enhancing the high-temperature strength and toughness of the material and optimizing the crystal structure of the brick. This achieves the maintenance of the structural integrity and mechanical properties of the brick at high temperatures, ensuring that the refractory insulation brick can withstand the stress under extreme high-temperature conditions and guaranteeing the normal progress of high-temperature industrial production processes.

[0038] By adding titanium dioxide nanoparticles, after surface functionalization treatment, they are evenly dispersed in the brick. Under light illumination conditions, the photocatalytic active sites on their surface can be excited, generating strongly oxidizing free radicals that decompose the organic dirt attached to the brick surface. This realizes the self-cleaning function, keeps the brick surface clean, and reduces problems such as the decline in heat transfer efficiency and the deterioration of brick performance caused by dirt accumulation.

[0039] By adding manganese oxide and cerium oxide, in a high-temperature environment, the composite powder formed by the two exhibits good oxidation catalytic performance. When the brick surface comes into contact with reducing substances or impurities, it can promote their oxidation reaction, converting these impurities into oxides that are easy to remove. This realizes the high-temperature oxidation self-cleaning function, further enhancing the ability of the brick to maintain cleanliness and performance stability in a complex high-temperature environment, reducing brick corrosion and performance decline caused by impurity deposition, and thus solving the problem that in a high-temperature industrial environment, dirt and impurities are easily attached to the surface of traditional refractory insulation bricks, affecting their heat insulation performance.

[0040] By adding yttrium oxide, it can promote the densification of other raw materials and refine the grains during the sintering process, thereby improving the density and strength of the brick, while also improving the thermal shock resistance of the brick. This realizes the optimization of the comprehensive performance of the brick, enabling the refractory insulation brick to achieve better balance and coordination in multiple performance indicators.

[0041] By adding microporous formers, such as one or a combination of rice husk ash, polystyrene microspheres, and graphite powder, specific-sized, shaped, distributed, and connected pores can be formed according to the design during the sintering process, effectively blocking the transfer of heat. This realizes excellent heat insulation performance, can effectively reduce the heat loss of equipment such as industrial kilns, reduce energy consumption, and improve energy utilization efficiency.

[0042] Please refer to the appendix Figure 1, The manufacturing process of multifunctional refractory insulation bricks includes the following steps:

[0043] S1. Raw material pretreatment: Pretreat silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, cleaning agent, yttrium oxide, and micropore former.

[0044] S2. Raw material mixing: Mix the pretreated silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, cleaning agent, yttrium oxide, and micropore former according to a ratio, and add a composite dispersant. Finish mixing when the relative standard deviation of the absorbance of each raw material is less than 2%.

[0045] S3. Molding treatment: Preheat the mold through an intelligent rubber mold, then fill the mixed raw materials into the mold and conduct preliminary compaction. Then, form the preliminarily compacted mold through a cold isostatic pressing device and release the pressure after molding.

[0046] S4. Sintering treatment: Sinter the formed raw materials through a sintering furnace to complete the preparation.

[0047] Specifically, by pretreating silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, cleaning agent, yttrium oxide, and micropore former, each raw material can reach appropriate particle size, purity, activity, and surface properties, ensuring that the raw materials can better participate in reactions and form a uniform structure in subsequent processes. Thus, a good foundation is laid for manufacturing high-performance multifunctional refractory insulation bricks, the utilization rate of raw materials is improved, and product defects and performance fluctuations caused by raw material problems are reduced.

[0048] By mixing the pretreated silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, cleaning agent, yttrium oxide, and micropore former according to a ratio and adding a composite dispersant, and finishing mixing when the relative standard deviation of the absorbance of each raw material is less than 2%, the raw materials can fully contact and synergistically act with each other, ensuring the consistency and stability of the brick body performance, improving the reliability of product quality, and ensuring the formation of a uniform and consistent microstructure and phase composition in subsequent molding and sintering processes.

[0049] By preheating the mold through an intelligent rubber mold, then filling the mixed raw materials into the mold and conducting preliminary compaction, and then forming the preliminarily compacted mold through a cold isostatic pressing device and releasing the pressure after molding, the raw materials are evenly pressured during the molding process, forming a brick blank with uniform density and few internal defects, improving the molding accuracy and quality. Thus, a brick blank with a complete structure, accurate dimensions, and stable performance is obtained, reducing the rejection rate caused by poor molding and providing a high-quality blank foundation for subsequent sintering, ensuring the mechanical strength and overall performance of the final product.

[0050] The prepared brick blank is sintered by passing the formed raw materials through a sintering furnace, thereby completing the preparation. During the sintering process, the brick blank undergoes precise physical and chemical changes to form an ideal crystal structure, functional phases, and pore distribution, thus manufacturing a refractory insulation brick with multiple functions such as wear resistance, heat insulation, and self-cleaning, excellent and stable performance, meeting the strict requirements of modern high-temperature industries for refractory insulation materials, improving the service life and reliability of products in high-temperature and complex environments, and enhancing the production efficiency and economic benefits of enterprises.

[0051] In step S1, the pretreatment of silicon carbide is carried out by a jet mill with an air flow pressure of 0.5 - 0.8 MPa and a flow rate of 30 - 50 m / s. The grinding medium is corundum balls with a diameter of 3 mm - 5 mm, and the particle size of silicon carbide is crushed to 5 - 15 μm.

[0052] The pretreatment of mullite, cordierite, alumina, and zirconia is to first coarsely crush them to a particle size of less than 3 mm by a jaw crusher, and then finely grind them by a planetary ball mill with a ball mill rotation speed of 400 - 600 r / min and a ball milling time of 6 - 8 hours. Triethanolamine with a dosage of 0.2% - 0.5% of the raw material mass is added as a grinding aid. After grinding, it is screened by multi-layer vibrating screens of 10 μm, 20 μm, and 30 μm. The part that does not meet the particle size requirements is ball milled and screened twice until the particle size is 10 - 30 μm and the distribution is uniform.

[0053] The pretreatment of titanium dioxide nanoparticles is to disperse them in an isopropyl alcohol solution containing a titanate coupling agent and a photocatalytic activity enhancer, and treat them under the synergistic action of stirring at 1000 - 1500 r / min and ultrasonic waves with a frequency of 40 kHz and a power of 500 W for 2 - 3 hours. Then, it is centrifuged at 8000 - 10000 r / min and washed 3 - 5 times with absolute ethanol. The activity improvement rate is more than 30%. The dosage of the titanate coupling agent is 3% - 6% of the particle mass, the photocatalytic activity enhancer is silver nanoparticles with a particle size of 10 - 20 nm, and the dosage is 1% - 3% of the particle mass.

[0054] The pretreatment of the cleaning agent is to separately prepare aqueous solutions of manganese nitrate and cerium nitrate with a concentration of 0.5 - 1.0 mol / L. After stirring at 600 - 800 r / min with a magnetic stirrer, 2 - 3 mol / L ammonia water is added dropwise. The reaction temperature is 40 - 60 °C, and the pH value is 8 - 10. After precipitation, it is aged for 4 - 6 hours, centrifuged at 6000 - 8000 r / min by a centrifuge until the conductivity of the washing liquid is less than 50 μS / cm, dried at 100 - 120 °C for 12 - 24 hours, and then calcined at 500 - 600 °C for 3 - 5 hours to obtain a manganese oxide - cerium oxide composite powder with a particle size of 10 - 30 nm.

[0055] The pretreatment of the microporous forming agent is to pre-burn rice husk ash in a high-temperature furnace at 600 - 800 °C for 2 - 3 hours, soak it in a dilute hydrochloric acid solution with a concentration of 3% - 5% and a liquid-solid ratio of 5:1 - 8:1 for 1 - 2 hours, then soak it in a sodium hydroxide solution with a concentration of 2% - 4% and a liquid-solid ratio of 4:1 - 6:1 for 1 - 2 hours. After leaching, rinse it with water until neutral, dry it at 120 - 150 °C for 3 - 5 hours, and finally process it with a planetary ball mill to a particle size of 5 - 15 μm. The rotation speed of the planetary ball mill is 500 - 700 r / min, and the ball milling time is 3 - 5 hours.

[0056] In step S2, the composite dispersant includes polyethylene glycol and stearic acid, and their ratio is 2:1 - 3:1 in sequence. The addition amount of the composite dispersant is 0.8% - 1.2% of the total mass of the raw materials.

[0057] In step S3, the heating channel of the intelligent rubber mold is spiral, with a diameter of 5 - 8 mm, a spacing of 10 - 15 mm, the power of the electric heating wire is 2 - 3 kW, the cooling uses circulating water, the flow rate of the circulating water pump is 5 - 10 L / min, the measurement range of the pressure sensor is 0 - 5 MPa, the measurement range of the flow controller for flow rate is 0 - 20 g / s, the preheating temperature is 60 - 90 °C, the pressure for filling the raw materials into the mold is 0.5 - 1.0 MPa, the speed is 5 - 10 g / s, the initial compaction is to hold the pressure at 2 - 3 MPa for 10 - 20 seconds, and it is formed by cold isostatic pressing equipment at a pre-pressure of 50 - 80 MPa for 30 - 60 seconds. Then, adjust the pressure rising rate and the target pressure value, hold the pressure at 180 - 220 MPa for 2 - 3 minutes, and the pressure relief rate after forming is 1 - 2 MPa / s.

[0058] In step S4, the brick blank is sintered by a sintering furnace, including the following steps:

[0059] S401: Heat the formed raw materials from room temperature to 500 - 600 °C at a rate of 3 - 5 °C / min through the sintering furnace, and at the same time introduce nitrogen, with a nitrogen flow rate of 5 - 10 L / min and the pressure maintained at +0.5 kPa;

[0060] S402: Then heat it to 1000 - 1200 °C at a rate of 2 - 4 °C / min, and at the same time introduce a mixture of hydrogen and nitrogen, with a flow rate of 5 - 10 L / min, the pressure maintained at +0.3 kPa, and the concentration of hydrogen is 2% - 5% of the volume ratio of the mixed gas;

[0061] S403: Then heat it to 1600 - 1800 °C at a rate of 1 - 3 °C / min, and at the same time introduce argon, with a flow rate of 15 - 20 L / min and the pressure maintained at +1 kPa;

[0062] S404, then reduce the argon flow rate to 5-8L / min, maintain the pressure at +0.3kPa, until the brick body cools to below 500°C, then take out the brick body and cool it naturally to room temperature to complete sintering, thereby completing the preparation.

[0063] Specifically, the formed raw materials are passed through a sintering furnace and the temperature is raised from room temperature to 500-600°C at a rate of 3-5°C / min. At the same time, nitrogen is introduced at a flow rate of 5-10L / min and the pressure is maintained at +0.5kPa, so that the air in the furnace is discharged by nitrogen to prevent the raw materials from being oxidized at the low temperature stage, because the oxygen in the air may react with some components in the raw materials (such as silicon carbide, metal oxides, etc.) to affect the performance of the brick, thereby protecting the raw materials from oxidation and ensuring that the raw materials maintain chemical stability during the initial heating process, providing a pure reaction environment for subsequent solid-phase reactions and functional phase formation, laying a good foundation, and avoiding the degradation of brick performance due to oxidation.

[0064] By raising the temperature to 1000-1200°C at a rate of 2-4°C / min, and introducing a mixture of hydrogen and nitrogen at a flow rate of 5-10L / min, the pressure is maintained at +0.3kPa, and the concentration of hydrogen is 2%-5% of the volume ratio of the mixed gas. The introduction of hydrogen helps to reduce the small amount of oxide impurities that may exist on the surface of the raw materials, and promotes further solid-phase reaction of the raw materials. For some metal oxide impurities, hydrogen can reduce them to metal elements, making the raw materials purer and conducive to the solid-phase reaction. At the same time, the surface of the titanium dioxide nanoparticles is slightly reduced to enhance the exposure of their photocatalytic active sites, thereby effectively promoting the solid-phase reaction process of the raw materials, and enhancing the activity of functional components (such as titanium dioxide), optimizing the microstructure and functional properties of the brick body, and improving the reactivity and performance improvement potential of the brick body in the subsequent high-temperature treatment process.

[0065] By raising the temperature to 1600-1800℃ at a rate of 1-3℃ / min, while introducing argon at a flow rate of 15-20L / min and maintaining the pressure at +1kPa, at high temperatures, if silicon carbide is oxidized, it will form oxides such as silicon dioxide, reducing its wear resistance, and the presence of argon can avoid this situation. At the same time, under this atmosphere, the manganese oxide-cerium oxide composite powder is more tightly bonded to the matrix material, forming a stable high-temperature oxidation cleaning functional phase, thereby ensuring the stability of the easily oxidizable components and promoting the perfect formation of the functional phase, ensuring that the brick body has excellent wear resistance and high-temperature oxidation self-cleaning function at high temperatures, so that the brick body can adapt to extremely high temperature and complex use environments and meet the strict requirements of high-temperature industrial production.

[0066] By reducing the argon gas flow rate to 5 - 8 L / min and maintaining the pressure at +0.3 kPa until the brick cools below 500 °C, then taking out the brick and allowing it to cool naturally to room temperature, the sintering is completed, thus completing the preparation. During the cooling process, if the brick comes into contact with air, stress may be generated inside the brick due to the temperature difference, and at the same time, the oxygen in the air may oxidize the surface of the brick, affecting its performance. Argon protection can avoid these problems, ensure the stability of the brick's performance, thus preventing structural damage and performance degradation of the brick caused by stress and oxidation during the cooling process, achieving the maintenance of the structural integrity and performance stability of the brick during the cooling process, ensuring the quality and reliability of the final product, and enabling the prepared multifunctional refractory insulation brick to stably perform its various functions during long-term use.

[0067] The following is a further introduction in combination with specific embodiments:

[0068] Example 1:

[0069] The multifunctional refractory insulation brick comprises the following raw materials in parts by weight: 15 parts of silicon carbide, 20 parts of mullite, 10 parts of cordierite, 40 parts of alumina, 10 parts of zirconia, 4 parts of titanium dioxide nanoparticles, 9 parts of a cleaning agent, 5 parts of yttrium oxide, and 12 parts of a microporous forming agent.

[0070] The cleaning agent comprises manganese oxide and cerium oxide, and their ratio is 4:2 in sequence.

[0071] The microporous forming agent is rice husk ash.

[0072] The manufacturing process of the multifunctional refractory insulation brick comprises the following steps:

[0073] S1. Pretreatment of raw materials: Pretreat silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, the cleaning agent, yttrium oxide, and the microporous forming agent.

[0074] S2. Mixing of raw materials: Mix the pretreated silicon carbide, mullite, cordierite, alumina, zirconia, titanium dioxide nanoparticles, the cleaning agent, yttrium oxide, and the microporous forming agent according to the ratio, and add a composite dispersant. When the relative standard deviation of the absorbance of each raw material is less than 2%, the mixing is completed.

[0075] S3. Molding treatment: Preheat the mold through an intelligent rubber mold, then fill the mixed raw materials into the mold, conduct preliminary compaction, and then form the preliminarily compacted mold through a cold isostatic pressing device and release the pressure after molding.

[0076] S4. Sintering treatment: Sinter the formed raw materials through a sintering furnace to complete the preparation of the brick blank.

[0077] In step S1, the pretreatment of silicon carbide is carried out by a jet mill with an air pressure of 0.65 MPa and a flow rate of 40 m / s. The grinding medium is corundum balls with a diameter of 4 mm, and the silicon carbide particle size is crushed to 10 μm.

[0078] The pretreatment of mullite, cordierite, alumina and zirconia is to first crush them coarsely to a particle size of less than 3 mm by a jaw crusher, and then finely grind them by a planetary ball mill with a rotational speed of 500 r / min for 7 hours. Triethanolamine with a dosage of 0.35% of the raw material mass is added as a grinding aid. After grinding, it is screened by a 20-μm multi-layer vibrating screen. The part that does not meet the particle size requirements is ball-milled and screened twice until the particle size is 20 μm and the distribution is uniform.

[0079] The pretreatment of titanium dioxide nanoparticles is to disperse them in an isopropanol solution containing a titanate coupling agent and a photocatalytic activity enhancer, and treat them for 2.5 hours under the synergistic action of stirring at 1300 r / min and ultrasonic waves with a frequency of 40 kHz and a power of 500 W. Then, it is centrifuged at 9000 r / min and washed 4 times with absolute ethanol. The activity improvement rate is 30%. The dosage of the titanate coupling agent is 4% of the particle mass, and the photocatalytic activity enhancer is silver nanoparticles with a particle size of 15 nm and a dosage of 2% of the particle mass.

[0080] The pretreatment of the cleaner is to separately prepare aqueous solutions of manganese nitrate and cerium nitrate with a concentration of 0.8 mol / L. After stirring at 700 r / min with a magnetic stirrer, 2 mol / L ammonia water is added dropwise. The reaction temperature is 50 °C, the pH value is 9. After precipitation, it is aged for 5 hours, centrifuged at 7000 r / min by a centrifuge until the conductivity of the washing liquid is less than 50 μS / cm, dried at 110 °C for 18 hours, and then calcined at 550 °C for 4 hours to obtain manganese oxide-cerium oxide composite powder with a particle size of 20 nm.

[0081] The pretreatment of the microporous former is to pre-burn rice husk ash in a high-temperature furnace at 700 °C for 2.5 hours, soak it in a dilute hydrochloric acid solution with a concentration of 4% and a liquid-solid ratio of 5-8 for 1.5 hours, then soak it in a sodium hydroxide solution with a concentration of 3% and a liquid-solid ratio of 4-6 for 1.5 hours. After leaching, it is rinsed with water until neutral, dried at 130 °C for 4 hours, and finally treated by a planetary ball mill to a particle size of 10 μm. The rotational speed of the planetary ball mill is 700 r / min, and the ball milling time is 5 hours.

[0082] In step S2, the composite dispersant includes polyethylene glycol and stearic acid, and their ratio is 2-3 in sequence. The addition amount of the composite dispersant is 1% of the total mass of the raw materials.

[0083] In step S3, the heating channels of the intelligent rubber mold are spiral, with a diameter of 8 mm, a pitch of 15 mm, the power of the electric heating wire is 3 kW, cooling is by circulating water, the flow rate of the circulating water pump is 10 L / min, the measurement range of the pressure sensor is 5 MPa, the flow measurement range of the flow controller is 10 g / s, the preheating temperature is 90 °C, the pressure for filling the raw material into the mold is 0.5 MPa, the speed is 5 g / s, the preliminary compaction is to hold the pressure at 2 MPa for 10 seconds, and it is formed by cold isostatic pressing equipment by pre-pressing at 50 MPa for 30 seconds. Then, the pressure rise rate and the target pressure value are adjusted, and it is held at a pressure of 180 MPa for 2 minutes. After forming, the pressure relief rate of pressure relief is 1 MPa / s.

[0084] In step S4, the brick blank is sintered in a sintering furnace, including the following steps:

[0085] S401: The formed raw material is heated from room temperature to 600 °C at a rate of 5 °C / min in the sintering furnace, and at the same time, nitrogen is introduced, the flow rate of nitrogen is 10 L / min, and the pressure is maintained at +0.5 kPa;

[0086] S402: Then it is heated to 1200 °C at a rate of 2 °C / min, and at the same time, hydrogen and nitrogen are introduced for mixing, the flow rate is 5 L / min, the pressure is maintained at +0.3 kPa, and the concentration of hydrogen is 2%-5% of the volume ratio of the mixed gas;

[0087] S403: Then it is heated to 1800 °C at a rate of 1 °C / min, and at the same time, argon is introduced, the flow rate is 15 L / min, and the pressure is maintained at +1 kPa;

[0088] S404: Then the flow rate of argon is reduced to 5 L / min, the pressure is maintained at +0.3 kPa until the brick body cools to 450 °C, and then the brick body is taken out and naturally cooled to room temperature to complete sintering, thus completing the preparation.

[0089] Example 2:

[0090] The difference between this example and the above Example 1 is as follows:

[0091] The multifunctional refractory heat-insulating brick is characterized in that it includes the following raw materials in parts by weight: 10 parts of silicon carbide, 10 parts of mullite, 5 parts of cordierite, 30 parts of alumina, 5 parts of zirconia, 2 parts of titanium dioxide nanoparticles, 6 parts of a cleaning agent, 3 parts of yttrium oxide, and 1 part of a micropore former.

[0092] The cleaning agent includes manganese oxide and cerium oxide, and their ratio is 3:1 in sequence.

[0093] Example 3:

[0094] The difference between this example and the above Example 1 is as follows:

[0095] Multi-functional refractory heat-insulating brick, characterized in that it comprises the following raw materials in parts by weight: 12.5 parts of silicon carbide, 15 parts of mullite, 7.5 parts of cordierite, 35 parts of alumina, 7.5 parts of zirconia, 3 parts of titanium dioxide nanoparticles, 7.5 parts of a cleaning agent, 4 parts of yttrium oxide, and 5.5 parts of a micropore former.

[0096] The cleaning agent comprises manganese oxide and cerium oxide, and their ratio is 3-4:2-1 in sequence.

[0097] Table 1:

[0098] Comparison Example 1 Example 2 Example 3 Standard value Removal rate of organic dirt 85％ 80％ 82％ 30％ Removal rate of inorganic dirt 75％ 70％ 72％ 20％ Thermal conductivity 0.45 W / (m·K) 0.48 W / (m·K) 0.46 W / (m·K) 1.2 W / (m·K)

[0099] The comparison in the above table is for traditional refractory heat-insulating bricks. It can be seen from Table 1 that different amounts of titanium dioxide nanoparticles and the manganese oxide-cerium oxide composite powder in the cleaning agent can affect the removal rates of organic and inorganic dirt of the refractory heat-insulating brick, and further affect the self-cleaning function of the refractory heat-insulating brick, thereby enhancing the ability of the brick body to maintain cleanliness and stable performance in a complex high-temperature environment, reducing the corrosion and performance decline of the brick body caused by impurity deposition, and reducing problems such as the decrease in heat transfer efficiency and the deterioration of the brick body performance caused by dirt accumulation.

[0100] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Multifunctional refractory insulation bricks, characterized by: The invention comprises the following raw materials in parts by weight: 10-15 parts of silicon carbide, 10-20 parts of mullite, 5-10 parts of cordierite, 30-40 parts of aluminum oxide, 5-10 parts of zirconium oxide, 2-4 parts of titanium dioxide nanoparticles, 6-9 parts of cleaning agent, 3-5 parts of yttrium oxide and 1-12 parts of micropore former.

2. The multifunctional refractory insulation brick according to claim 1 is characterized in that: The cleaning agent includes manganese oxide and cerium oxide, and the ratios thereof are 3-4:2-1 respectively.

3. The multifunctional refractory insulation brick according to claim 1 is characterized in that: The micropore forming agent is one or more combinations of rice husk ash, polystyrene microspheres and graphite powder.

4. The manufacturing process of multifunctional refractory insulation bricks is characterized by: The multifunctional refractory heat-insulating brick used in any one of claims 1 to 3 comprises the following steps: S1. Raw material pretreatment: pretreatment of silicon carbide, mullite, cordierite, alumina, zirconium oxide, titanium dioxide nanoparticles, detergent, yttrium oxide, and micropore forming agent; S2, raw material mixing: pre-treated silicon carbide, mullite, cordierite, alumina, zirconium oxide, titanium dioxide nanoparticles, detergent, yttrium oxide, micropore forming agent are mixed according to proportion, and a composite dispersant is added. When the relative standard deviation of the absorbance of each raw material is less than 2%, the mixing is completed; S3, molding process: preheating the mold through the intelligent rubber mold, then filling the mixed raw materials into the mold, performing preliminary compaction, and then molding the preliminary compacted mold through cold isostatic pressing equipment, and releasing the pressure after molding; S4, sintering treatment: the formed raw materials are passed through a sintering furnace to sinter the bricks to complete the preparation.

5. The manufacturing process of the multifunctional refractory heat-insulating brick according to claim 4 is characterized in that: In step S1, the silicon carbide is pretreated by jet milling, with an airflow pressure of 0.5-0.8 MPa, a flow rate of 30-50 m / s, and a grinding medium of corundum balls with a diameter of 3 mm-5 mm, to crush the silicon carbide particles to 5-15 μm; The mullite, cordierite, alumina and zirconia are pretreated by first being coarsely crushed by a jaw crusher to a particle size of less than 3 mm, then finely ground by a planetary ball mill, the ball mill speed is 400-600 r / min, the ball milling time is 6-8 hours, and 0.2%-0.5% of triethanolamine by weight of the raw materials is added as a grinding aid, and after grinding, they are sieved by a 10μm, 20μm and 30μm multi-layer vibrating screen, and the part that does not meet the particle size requirements is ball-milled and sieved again to a particle size of 10-30μm and evenly distributed; The titanium dioxide nanoparticles are pretreated by dispersing them in an isopropanol solution containing a titanate coupling agent and a photocatalytic activity enhancer, treating them for 2-3 hours under the synergistic effect of stirring at 1000-1500 r / min and ultrasound at a frequency of 40 kHz and a power of 500 W, then centrifuging at 8000-10000 r / min, washing with anhydrous ethanol for 3-5 times, and the activity improvement rate is more than 30%, the titanate coupling agent is used in an amount of 3%-6% of the particle mass, and the photocatalytic activity enhancer is silver nanoparticles with a particle size of 10-20 nm and an amount of 1%-3% of the particle mass; The cleaning agent pretreatment comprises preparing 0.5-1.0 mol / L manganese nitrate and cerium nitrate aqueous solutions respectively, stirring with a magnetic stirrer at 600-800 r / min, then dropping 2-3 mol / L ammonia water, the reaction temperature is 40-60° C., the pH value is 8-10, aging for 4-6 hours after precipitation is completed, centrifuging with a centrifuge at 6000-8000 r / min until the conductivity of the washing liquid is less than 50 μS / cm, drying at 100-120° C. for 12-24 hours, and then calcining at 500-600° C. for 3-5 hours to obtain a manganese oxide-cerium oxide composite powder with a particle size of 10-30 nm; The micropore forming agent pretreatment is to pre-burn the rice husk ash in a high-temperature furnace at 600-800°C for 2-3 hours, soak it in a dilute hydrochloric acid solution with a concentration of 3%-5% and a liquid-to-solid ratio of 5:1-8:1 for 1-2 hours, and then soak it in a sodium hydroxide solution with a concentration of 2%-4% and a liquid-to-solid ratio of 4:1-6:1 for 1-2 hours, rinse it with clean water to neutrality after leaching, dry it at 120-150°C for 3-5 hours, and finally process it in a planetary ball mill to a particle size of 5-15μm, the rotation speed of the planetary ball mill is 500-700r / min, and the ball milling time is 3-5 hours.

6. The manufacturing process of the multifunctional refractory heat-insulating brick according to claim 4 is characterized in that: The composite dispersant in step S2 includes polyethylene glycol and stearic acid in a ratio of 2:1-3:1, and the added amount of the composite dispersant is 0.8%-1.2% of the total mass of the raw materials.

7. The manufacturing process of the multifunctional refractory insulation brick according to claim 4 is characterized in that: The heating channel of the smart rubber mold in step S3 is spiral, with a diameter of 5-8mm, a spacing of 10-15mm, an electric heating wire power of 2-3kW, circulating water for cooling, a circulating water pump flow of 5-10L / min, a pressure sensor measuring range of 0-5MPa, a flow controller flow measuring range of 0-20g / s, the preheating temperature of 60-90°C, the pressure of filling the raw material into the mold is 0.5-1.0MPa, and the speed is 5-10g / s. The initial compaction is to maintain the pressure at 2-3MPa for 10-20 seconds, and the molding by cold isostatic pressing equipment is to pre-press at 50-80MPa for 30-60 seconds, and then adjust the pressure rise rate and the target pressure value to maintain the pressure at 180-220MPa for 2-3 minutes, and the pressure relief rate of the pressure relief after molding is 1-2MPa / s.

8. The manufacturing process of the multifunctional refractory heat-insulating brick according to claim 4 is characterized in that: In the step S4, the bricks are sintered by a sintering furnace, comprising the following steps: S401, heating the formed raw material from room temperature to 500-600°C at 3-5°C / min through a sintering furnace, while introducing nitrogen at a flow rate of 5-10 L / min and maintaining the pressure at +0.5 kPa; S402, then raise the temperature to 1000-1200°C at 2-4°C / min, and introduce a mixture of hydrogen and nitrogen at a flow rate of 5-10L / min, and maintain the pressure at +0.3kPa. The concentration of hydrogen is 2%-5% of the volume ratio of the mixed gas; S403, then raise the temperature to 1600-1800°C at a rate of 1-3°C / min, while introducing argon at a flow rate of 15-20L / min, and maintaining the pressure at +1kPa; S404, then reduce the argon flow rate to 5-8L / min, maintain the pressure at +0.3kPa, until the brick body cools to below 500°C, then take out the brick body and naturally cool it to room temperature to complete sintering, thereby completing the preparation.

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