High-strength anti-stripping industrial kiln castable and preparation method thereof

Abstract

The invention belongs to the technical field of refractory materials, and particularly relates to a high-strength anti-stripping industrial kiln castable and a preparation method thereof. The industrial kiln castable provided by the invention is prepared from white corundum, modified corundum, petalite, composite micro powder, modified micro powder, a binding agent and sodium hexametaphosphate. White corundum, modified corundum and petalite are adopted as aggregates of the kiln castable, and composite micro powder and nano micro powder are added to fill gaps of the aggregates, so that the porosity of the castable is reduced; the corundum is doped with titanium dioxide to form a solid solution, and the surface of the nano titanium diboride is coated with a silicon oxide ceramic layer by a sol-gel method, so that the interface bonding force between the nano titanium diboride and a matrix is enhanced, rigid reinforcing points are increased, and the high-temperature compressive strength is improved.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, specifically relating to a high-strength, anti-stripping industrial kiln castable and its preparation method. Background Technology

[0002] Industrial kilns, as core thermal equipment in metallurgy, building materials, chemical industry, ceramics, and other fields, typically operate under harsh conditions including high temperatures, drastic temperature fluctuations, molten material erosion, airflow scouring, and mechanical vibration. The kiln lining material, as a key component ensuring the safe and stable operation of the kiln and extending its service life, directly determines the kiln's production efficiency, product quality, and operating costs. Among various kiln lining materials, castables, due to their advantages such as convenient construction, good integrity, and strong adaptability, have gradually replaced traditional refractory bricks and become the mainstream choice for lining medium and large-sized industrial kilns.

[0003] While commercially available industrial kiln castables can meet some conventional operating requirements in terms of room temperature strength and basic high-temperature resistance, they generally suffer from two major defects in complex and harsh actual operating environments: First, insufficient high-temperature strength, which easily softens and creeps under long-term high-temperature loads, leading to deformation and cracking of the lining structure, and subsequently causing leakage of molten materials, and in severe cases, even requiring kiln shutdown for maintenance; Second, poor resistance to thermal shock spalling. The drastic temperature changes during kiln start-up and shutdown will generate huge thermal stress inside the castable. When the thermal stress exceeds the material's own crack resistance, surface spalling, delamination, or even overall collapse are very likely to occur, significantly shortening the service life of the lining material.

[0004] To address the insufficient high-temperature strength performance, current industry improvements typically involve increasing the content of aggregates such as high-alumina bauxite and corundum to enhance the strength of castables. However, this increases the thermal conductivity of the material, exacerbating thermal stress concentration and consequently reducing its anti-stripping performance. Regarding the insufficient thermal shock resistance, current industry improvements generally involve adding organic fibers and metal fibers. However, organic fibers are prone to combustion and carbonization at high temperatures, forming pores, while metal fibers may lose their reinforcing effect after high-temperature oxidation. Neither approach can achieve a synergistic improvement in both strength and anti-stripping performance.

[0005] Chinese patent application CN111423242A discloses a spalling-resistant and thermally shock-resistant castable, which is prepared from the following raw materials in parts by weight: 40 to 60 parts of waste zircon brick particles and fine powder from glass kilns, 15 to 30 parts of waste silicon carbide kiln board particles, 1 to 10 parts of fused silica particles, 10 to 20 parts of mullite fine powder, 3 to 15 parts of aluminate cement, 3 to 5 parts of silica micropowder, 3 to 5 parts of alumina micropowder, 1 to 3 parts of metallic silicon powder, and 1 to 2 parts of one or both of sodium tripolyphosphate and sodium hexametaphosphate. Using synthetic materials with low thermal expansion coefficients and good thermal shock stability can improve the spalling resistance and thermal shock resistance of refractory materials. However, waste zircon brick particles from glass kilns may undergo interfacial reactions with molten glass during service, potentially introducing alkali metal or alkaline earth metal impurities such as sodium oxide and calcium oxide, forming low-melting-point phases. Molten quartz particles undergo crystal transformation above 1100℃, accompanied by volume expansion, leading to microcracks in the castable and a decrease in its erosion resistance. Summary of the Invention

[0006] To address the technical problems of insufficient high-temperature strength and poor thermal shock spalling resistance in the aforementioned related technologies, this invention provides a high-strength, spalling-resistant industrial kiln castable and its preparation method.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A high-strength, anti-stripping industrial kiln castable comprises the following components in parts by weight: 80-90 parts white fused alumina, 20-40 parts modified fused alumina, 35-40 parts petalite, 30-45 parts composite micro powder, 10-20 parts modified micro powder, 20-30 parts binder, and 5-10 parts sodium hexametaphosphate. The modified corundum is prepared by mixing alumina powder and titanium dioxide powder evenly, adding polyvinyl alcohol solution and sodium hexametaphosphate for granulation, drying, sintering at 1200-1300℃ for 2-3 hours, then heating to 1800℃ for 4-6 hours, cooling and crushing to obtain modified corundum.

[0008] In the above scheme, white fused alumina, modified fused alumina, and petalite are used as aggregates for kiln castables. These aggregates have a low coefficient of thermal expansion at high temperatures. The addition of composite micro-powders and nano-powders fills the gaps in the aggregates, forming a dense packing structure, reducing the porosity of the castables, and increasing their density. Among them, petalite crystals have an extremely low coefficient of thermal expansion and good compatibility with components such as white fused alumina. They can promote the formation of a low-expansion glassy phase or microcrystalline phase in the matrix, reducing the thermal shock sensitivity of the castables and preventing spalling due to sudden temperature changes. Modified fused alumina is made by doping a trace amount of titanium dioxide into fused alumina. The ionic radius of titanium ions is close to that of aluminum ions. At high temperatures, titanium ions can replace aluminum ions in the fused alumina lattice to form an Al2O3-TiO2 solid solution, resulting in lattice distortion, refining the aggregate grains, increasing the grain boundary area, and increasing the resistance to grain boundary slip at high temperatures. This improves the high-temperature compressive strength of the castables and reduces the coefficient of thermal expansion of the aggregates.

[0009] Furthermore, in the preparation method of modified corundum, the mass of titanium dioxide powder is 1%-2% of the mass of alumina powder.

[0010] In the above scheme, it is necessary to precisely control the amount of titanium dioxide powder. A small amount of titanium dioxide doping can refine the grains and improve the high-temperature compressive strength. However, excessive doping will cause the precipitation of a second phase of titanium dioxide in the modified corundum, which will lead to a decrease in high-temperature compressive strength.

[0011] Furthermore, in the preparation method of modified corundum, the polyvinyl alcohol solution has a mass percentage of 5%-7%, and the amount of polyvinyl alcohol solution used is 12%-15% of the mass of alumina powder; the amount of sodium hexametaphosphate used is 0.2%-0.5% of the mass of alumina powder.

[0012] Furthermore, in the preparation method of modified corundum, the heating rate for sintering at 1200-1300℃ is 3-5℃ / min, and the heating rate to 1800℃ is 1-3℃ / min; the specific cooling process is as follows: the cooling rate from 1800-1000℃ is 2-3℃ / min, and the temperature is reduced to 1000℃ before furnace cooling.

[0013] In the above scheme, using a faster heating rate initially can shorten the heating time and increase the sintering rate. Once the temperature reaches 1300℃, using a slower heating rate can avoid lattice defects in the modified corundum. During the cooling process, using a slower cooling rate between 1800-1000℃ can avoid lattice stress caused by rapid cooling.

[0014] Furthermore, the composite micro powder is composed of white corundum powder, mullite powder, aluminum powder and silicon powder in a mass ratio of 1:(0.5-0.7):(0.04-0.06):(0.02-0.05).

[0015] In the above scheme, the composite micro-powder composed of white fused alumina powder, mullite powder, aluminum powder, and silicon powder can effectively fill the gaps between aggregates, achieve a multi-level particle packing structure, and reduce porosity. Among them, white fused alumina powder and mullite powder synergistically construct a high refractoriness matrix, and the low expansion characteristics can give the matrix a good thermal shock resistance. White fused alumina powder can also provide sufficient alumina raw materials for the mullite reaction. Aluminum powder and silicon powder have high activity and will undergo oxidation or solid-phase reaction first in the medium and high temperature stage (800-1200℃), generating ceramic phases such as alumina or silicon nitride to fill pores and strengthen grain boundaries, achieving in-situ toughening and reinforcement, and significantly improving the compressive strength of castables at high temperatures.

[0016] Furthermore, the modified micro powder is prepared as follows: nano-titanium diboride is soaked in nitric acid solution for 2-2.5 hours, filtered, washed, and dried to obtain acidified nano-titanium diboride; tetraethyl orthosilicate and anhydrous ethanol are mixed evenly, and nitric acid solution is slowly added and stirred for 12-15 hours to obtain silica sol; acidified nano-titanium diboride is added to silica sol, stirred for 2-4 hours, vacuum rotary evaporated at 50-60℃ for 4-6 hours, then dried at 80-90℃ for 10-12 hours, ground, passed through a 500-mesh sieve, heated to 800℃ under a nitrogen atmosphere, held for 2-3 hours for sintering, and cooled with the furnace to obtain modified micro powder.

[0017] In the above scheme, a layer of silicon oxide ceramic is coated on the surface of nano-titanium diboride using the sol-gel method to enhance the interfacial bonding force between nano-titanium diboride and the matrix. Titanium diboride is an ultra-high hardness ceramic phase. When added to the castable, it can act as a rigidity reinforcement point during high-temperature use, hindering the slippage and growth of grains in the matrix, significantly reducing the high-temperature creep rate of the castable, and improving the high-temperature compressive strength.

[0018] Furthermore, in the preparation method of the modified micro powder, the mass percentage of the nitric acid solution is 3%-5%; the mass ratio of the tetraethyl orthosilicate, anhydrous ethanol, and nitric acid solution is 1:(0.89-0.92):(0.55-0.61); and the mass ratio of the nano-titanium diboride and silica sol is (10-15):(3-7).

[0019] Furthermore, the white corundum has a particle size of 5-10 mm, the modified corundum has a particle size of 3-5 mm, the petalite has a particle size of 1-3 mm, and the composite micro powder has a particle size of 15-20 μm.

[0020] Furthermore, the binder is calcium aluminate cement.

[0021] In the above scheme, pure calcium aluminate cement generates high-melting-point minerals such as CA2 and CA6 at high temperatures, without the strength loss caused by the decomposition of hydration products such as ettringite.

[0022] This invention also provides a method for preparing the high-strength anti-stripping industrial kiln castable, specifically: mixing white corundum, modified corundum, petalite, composite micro powder, modified micro powder, binder and sodium hexametaphosphate evenly to obtain the high-strength anti-stripping industrial kiln castable. When using it, add water in a high-power mixer and stir evenly for 5-10 minutes before masonry work can be carried out.

[0023] The above scheme adopts a dry mixing process, which shortens the production cycle and reduces equipment and labor costs.

[0024] Compared with the prior art, the high-strength anti-stripping industrial kiln castable and its preparation method provided by the present invention have the following technical advantages: (1) The present invention uses white corundum, modified corundum and lithite as aggregates for kiln castables, and adds composite micro powder and nano powder to fill the gaps in the aggregates to form a dense packing structure and reduce the porosity of the castable. (2) In this invention, titanium dioxide is used to dope corundum to form Al2O3-TiO2 solid solution, which refines aggregate grains, increases resistance to grain boundary slip, and improves the high temperature compressive strength of castable. (3) The present invention uses white corundum powder, mullite powder, aluminum powder and silicon powder to form a composite micro powder, which can effectively fill the gaps between aggregates, realize a multi-level particle stacking structure, and reduce porosity. (4) The present invention uses the sol-gel method to coat a layer of silicon oxide ceramic on the surface of nano titanium diboride, which strengthens the interfacial bonding force between nano titanium diboride and the matrix, increases the rigidity enhancement points, and improves the high temperature compressive strength. Detailed Implementation

[0025] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments. Those skilled in the art can make various modifications based on the fundamental principles of the present invention, but all modifications that do not depart from the fundamental principles of the present invention are within its scope.

[0026] The preparation method of the high-strength anti-stripping industrial kiln castable described in this embodiment is as follows: white corundum, modified corundum, lithium feldspar, composite micro powder, modified micro powder, binder and sodium hexametaphosphate are mixed evenly to obtain high-strength anti-stripping industrial kiln castable. When using it, water is added to a high-power mixer and stirred evenly for 5-10 minutes before masonry work can be carried out.

[0027] In this embodiment, the white corundum has a particle size of 5-10 mm, the modified corundum has a particle size of 3-5 mm, the petalite has a particle size of 1-3 mm, and the composite micro powder has a particle size of 15-20 μm.

[0028] Example 1 A high-strength, anti-stripping industrial kiln castable comprises the following components in parts by weight: 80g white fused alumina, 20g modified fused alumina, 35g petalite, 45g composite micro powder, 20g modified micro powder, 30g calcium aluminate cement, 10g sodium hexametaphosphate. The modified corundum is prepared by mixing 100g of alumina powder and 1g of titanium dioxide powder evenly, adding 12g of 5% polyvinyl alcohol solution and 0.2g of sodium hexametaphosphate for granulation, preparing green body particles with a particle size of 5mm, placing them in a hot air drying oven and drying at 110℃ for 24h, heating to 1200℃ at a heating rate of 3℃ / min and sintering for 2h, then heating to 1800℃ at a heating rate of 1℃ / min and sintering for 4h, cooling to 1000℃ at a cooling rate of 2℃ / min and then cooling in the furnace, crushing to obtain modified corundum.

[0029] The composite micro powder is composed of white corundum powder, mullite powder, aluminum powder and silicon powder in a mass ratio of 1:0.5:0.04:0.02.

[0030] The modified micro powder was prepared as follows: 100g of nano-titanium diboride was soaked in 200mL of 3% nitric acid solution for 2h, filtered, washed, and dried to obtain acidified nano-titanium diboride; 100g of tetraethyl orthosilicate and 89g of anhydrous ethanol were mixed evenly, and 55g of 3% nitric acid solution was slowly added and stirred for 12h to obtain silica sol; the acidified nano-titanium diboride was added to 30g of silica sol, stirred for 2h, vacuum rotary evaporated at 50℃ for 4h, then dried at 80℃ for 10h, ground, passed through a 500-mesh sieve, heated to 500℃ at a rate of 3℃ / min under a nitrogen atmosphere, then heated to 800℃ at a rate of 2℃ / min, held for 2h, and cooled in the furnace to obtain the modified micro powder.

[0031] Example 2 A high-strength, anti-stripping industrial kiln castable comprises the following components in parts by weight: 90g white fused alumina, 40g modified fused alumina, 40g petalite, 30g composite micro powder, 10g modified micro powder, 20g calcium aluminate cement, 5g sodium hexametaphosphate. The modified corundum is prepared by mixing 100g of alumina powder and 2g of titanium dioxide powder evenly, adding 15g of 7% polyvinyl alcohol solution and 0.5g of sodium hexametaphosphate for granulation to prepare green body particles with a particle size of 15mm. The particles are then placed in a hot air drying oven and dried at 120℃ for 24h. The temperature is then increased to 1300℃ at a heating rate of 5℃ / min and sintered for 3h. The temperature is then increased to 1800℃ at a heating rate of 3℃ / min and sintered for 6h. Finally, the temperature is decreased to 1000℃ at a cooling rate of 3℃ / min and cooled in the furnace. The particles are then crushed to obtain modified corundum.

[0032] The composite micro powder is composed of white corundum powder, mullite powder, aluminum powder and silicon powder in a mass ratio of 1:0.7:0.06:0.05.

[0033] The modified micro powder was prepared as follows: 150g of nano-titanium diboride was soaked in 200mL of 5% nitric acid solution for 2.5h, filtered, washed, and dried to obtain acidified nano-titanium diboride; 100g of tetraethyl orthosilicate and 92g of anhydrous ethanol were mixed evenly, and 61g of 5% nitric acid solution was slowly added and stirred for 15h to obtain silica sol; the acidified nano-titanium diboride was added to 70g of silica sol, stirred for 4h, vacuum rotary evaporated at 60℃ for 6h, then dried at 90℃ for 12h, ground, passed through a 500-mesh sieve, heated to 500℃ at a rate of 3℃ / min under a nitrogen atmosphere, then heated to 800℃ at a rate of 2℃ / min, held for 3h, and cooled in the furnace to obtain the modified micro powder.

[0034] Example 3 A high-strength, anti-stripping industrial kiln castable comprises the following components in parts by weight: 85g white fused alumina, 30g modified fused alumina, 37g petalite, 40g composite micro powder, 15g modified micro powder, 25g calcium aluminate cement, and 8g sodium hexametaphosphate. The modified corundum is prepared by mixing 100g of alumina powder and 1.5g of titanium dioxide powder evenly, adding 13g of 6% polyvinyl alcohol solution and 0.4g of sodium hexametaphosphate for granulation to prepare 10mm particle size blanks. The blanks are placed in a hot air drying oven and dried at 115℃ for 24h. The temperature is then increased to 1250℃ at a heating rate of 4℃ / min and sintered for 2.5h. The temperature is then increased to 1800℃ at a heating rate of 2℃ / min and sintered for 5h. The temperature is then decreased to 1000℃ at a cooling rate of 2.5℃ / min and cooled in the furnace. The blanks are then crushed to obtain modified corundum.

[0035] The composite micro powder is composed of white corundum powder, mullite powder, aluminum powder and silicon powder in a mass ratio of 1:0.6:0.05:0.04.

[0036] The modified micro powder was prepared as follows: 130g of nano-titanium diboride was soaked in 200mL of 4% nitric acid solution for 2.2h, filtered, washed, and dried to obtain acidified nano-titanium diboride; 100g of tetraethyl orthosilicate and 90g of anhydrous ethanol were mixed evenly, and 58g of 4% nitric acid solution was slowly added and stirred for 14h to obtain silica sol; the acidified nano-titanium diboride was added to 45g of silica sol, stirred for 3h, vacuum rotary evaporated at 55℃ for 5h, then dried at 85℃ for 11h, ground, passed through a 500-mesh sieve, heated to 500℃ at a rate of 3℃ / min under a nitrogen atmosphere, then heated to 800℃ at a rate of 2℃ / min, held for 2.5h, and cooled in the furnace to obtain the modified micro powder.

[0037] Example 4 A high-strength, anti-stripping industrial kiln castable comprises the following components in parts by weight: 88g white fused alumina, 32g modified fused alumina, 38g petalite, 39g composite micro powder, 16g modified micro powder, 25g calcium aluminate cement, and 8g sodium hexametaphosphate. The modified corundum is prepared by mixing 100g of alumina powder and 1.6g of titanium dioxide powder evenly, adding 14g of 6% polyvinyl alcohol solution and 0.3g of sodium hexametaphosphate for granulation to prepare green body particles with a particle size of 10mm. The particles are then placed in a hot air drying oven and dried at 115℃ for 24h. The temperature is then increased to 1250℃ at a heating rate of 4℃ / min and sintered for 2.5h. The temperature is then increased to 1800℃ at a heating rate of 2℃ / min and sintered for 5h. Finally, the temperature is decreased to 1000℃ at a cooling rate of 2.5℃ / min and cooled in the furnace. The particles are then crushed to obtain the modified corundum.

[0038] The composite micro powder is composed of white corundum powder, mullite powder, aluminum powder and silicon powder in a mass ratio of 1:0.6:0.05:0.03.

[0039] The modified micro powder was prepared as follows: 135g of nano-titanium diboride was soaked in 200mL of 4% nitric acid solution for 2.2h, filtered, washed, and dried to obtain acidified nano-titanium diboride; 100g of tetraethyl orthosilicate and 90g of anhydrous ethanol were mixed evenly, and 58g of 4% nitric acid solution was slowly added and stirred for 13h to obtain silica sol; the acidified nano-titanium diboride was added to 52g of silica sol, stirred for 3h, vacuum rotary evaporated at 55℃ for 5h, then dried at 85℃ for 11h, ground, passed through a 500-mesh sieve, heated to 500℃ at a rate of 3℃ / min under a nitrogen atmosphere, then heated to 800℃ at a rate of 2℃ / min, held for 2.5h, and cooled in the furnace to obtain the modified micro powder.

[0040] Comparative Example 1 The industrial kiln castable in this comparative example is similar to that in Example 4. The difference between this comparative example and Example 4 is that an equal amount of white corundum is used instead of modified corundum in this comparative example.

[0041] Comparative Example 2 The industrial kiln castable in this comparative example is similar to that in Example 4. The difference between this comparative example and Example 4 is that an equal amount of white corundum is used instead of lepidolite in this comparative example.

[0042] Comparative Example 3 The industrial kiln castable in this comparative example is similar to that in Example 4. The difference between this comparative example and Example 4 is that an equal amount of white corundum powder is used to replace aluminum powder in the composite micro powder of this comparative example.

[0043] Comparative Example 4 The industrial kiln castable in this comparative example is similar to that in Example 4. The difference between this comparative example and Example 4 is that an equal amount of white corundum powder is used to replace silicon powder in the composite micro powder of this comparative example.

[0044] Comparative Example 5 The industrial kiln castable in this comparative example is similar to that in Example 4. The difference between this comparative example and Example 4 is that an equal amount of nano-titanium diboride is used instead of the modified micro powder in this comparative example.

[0045] Comparative Example 6 The industrial kiln castable in this comparative example is similar to that in Example 4. The difference between this comparative example and Example 4 is that an equal amount of alumina powder is used instead of modified micro powder in this comparative example.

[0046] Test case Thermal shock resistance test: The industrial kiln castables prepared in Examples 1-4 and Comparative Examples 1-6 were mixed with water and then applied to a test column in a conventional manner. After drying, the mixture was tested. The test column was made of graphite carbon fiber cloth and could withstand a maximum temperature of 2500℃. Thermal shock resistance is expressed as the number of times it can withstand alternating cycles between water cooling and 1400℃.

[0047] Mechanical property testing: The room temperature compressive strength of the castables prepared in Examples 1-4 and Comparative Examples 1-6 was tested according to GB / T 5072-2023; the high temperature compressive strength of the castables prepared in Examples 1-4 and Comparative Examples 1-6 was tested according to GB / T 34218-2025; the room temperature flexural strength of the refractory materials prepared in Examples 1-4 and Comparative Examples 1-6 was tested according to GB / T 3001-2017; and the high temperature flexural strength of the refractory materials prepared in Examples 1-4 and Comparative Examples 1-6 was tested according to GB / T 3002-2017.

[0048] The experimental results are shown in Table 1.

[0049] Table 1 Performance Test Results

[0050] As shown in Table 1, the high-strength anti-stripping industrial kiln castable provided by the present invention has a thermal shock resistance of more than 55 cycles, a room temperature compressive strength of 120.6-123.6 MPa, a high temperature compressive strength of 118.5-123.2 MPa, a room temperature flexural strength of 11.2-12.8 MPa, and a high temperature flexural strength of 10.3-12.3 MPa. This fully demonstrates that the high-strength anti-stripping industrial kiln castable provided by the present invention has good thermal shock resistance and high temperature mechanical properties.

[0051] The above embodiments are merely illustrative of the present invention and are not intended to limit the invention. Those skilled in the art should not modify the above embodiments without departing from the spirit and scope of the present invention. All equivalent modifications or alterations made by those skilled in the art without departing from the technical concept of the present invention are still within the protection scope of the present invention.

Claims

1. A high-strength, anti-stripping industrial kiln castable, characterized in that, The components include the following parts by weight: 80-90 parts white fused alumina, 20-40 parts modified fused alumina, 35-40 parts petalite, 30-45 parts composite micro powder, 10-20 parts modified micro powder, 20-30 parts binder, and 5-10 parts sodium hexametaphosphate. The modified corundum is prepared by mixing alumina powder and titanium dioxide powder evenly, adding polyvinyl alcohol solution and sodium hexametaphosphate for granulation, drying, sintering at 1200-1300℃ for 2-3 hours, then heating to 1800℃ for 4-6 hours, cooling and crushing to obtain modified corundum. The composite micro powder is composed of white corundum powder, mullite powder, aluminum powder and silicon powder in a mass ratio of 1:(0.5-0.7):(0.04-0.06):(0.02-0.05); The modified micro powder is prepared as follows: nano-titanium diboride is soaked in nitric acid solution for 2-2.5 hours, filtered, washed, and dried to obtain acidified nano-titanium diboride; tetraethyl orthosilicate and anhydrous ethanol are mixed evenly, and nitric acid solution is slowly added and stirred for 12-15 hours to obtain silica sol; acidified nano-titanium diboride is added to silica sol, stirred for 2-4 hours, vacuum rotary evaporated at 50-60℃ for 4-6 hours, then dried at 80-90℃ for 10-12 hours, ground, passed through a 500-mesh sieve, heated to 800℃ under a nitrogen atmosphere, held for 2-3 hours, and cooled in the furnace to obtain modified micro powder; The binder is calcium aluminate cement.

2. The high-strength, anti-stripping industrial kiln castable according to claim 1, characterized in that, In the preparation method of modified corundum, the mass of titanium dioxide powder is 1%-2% of the mass of alumina powder.

3. The high-strength, anti-stripping industrial kiln castable according to claim 1, characterized in that, In the preparation method of modified corundum, the mass percentage of the polyvinyl alcohol solution is 5%-7%, and the amount of polyvinyl alcohol solution used is 12%-15% of the mass of alumina powder; the amount of sodium hexametaphosphate used is 0.2%-0.5% of the mass of alumina powder.

4. The high-strength, anti-stripping industrial kiln castable according to claim 1, characterized in that, In the preparation method of modified corundum, the heating rate for sintering at 1200-1300℃ is 3-5℃ / min, and the heating rate to 1800℃ is 1-3℃ / min; the specific cooling process is as follows: the cooling rate from 1800-1000℃ is 2-3℃ / min, and the temperature is reduced to 1000℃ and then cooled with the furnace.

5. The high-strength, anti-stripping industrial kiln castable according to claim 1, characterized in that, In the preparation method of the modified micro powder, the mass percentage of the nitric acid solution is 3%-5%; the mass ratio of the tetraethyl orthosilicate, anhydrous ethanol, and nitric acid solution is 1:(0.89-0.92):(0.55-0.61); and the mass ratio of the nano-titanium diboride and silica sol is (10-15):(3-7).

6. The high-strength, anti-stripping industrial kiln castable according to claim 1, characterized in that, The white corundum has a particle size of 5-10 mm, the modified corundum has a particle size of 3-5 mm, the petalite has a particle size of 1-3 mm, and the composite micro powder has a particle size of 15-20 μm.

7. The method for preparing high-strength, anti-stripping industrial kiln castable according to any one of claims 1-6, characterized in that, Specifically, white corundum, modified corundum, petalite, composite micro powder, modified micro powder, binder and sodium hexametaphosphate are mixed evenly to obtain high-strength anti-stripping industrial kiln castable. When using it, add water in a high-power mixer and mix evenly for 5-10 minutes before masonry work.

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