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

Abstract

The application belongs to the technical field of refractory materials, and particularly relates to high-strength anti-stripping industrial kiln castable and a preparation method thereof. The industrial kiln castable provided by the application comprises white corundum, modified corundum, petalite, composite micropowder, modified micropowder, a binder and sodium hexametaphosphate. The white corundum, the modified corundum and the petalite are used as aggregates of the kiln castable, the composite micropowder and the nano micropowder are added to fill the aggregate gaps, and the porosity of the castable is reduced. The titanium dioxide is used to dope the corundum to form a solid solution, and a silica ceramic layer is coated on the surface of the nano titanium diboride by using a sol-gel method, so that the interface bonding force between the nano titanium diboride and the matrix is strengthened, the rigid reinforcing points are increased, and the high-temperature compressive strength is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory materials, and particularly relates to a high-strength anti-spalling industrial kiln castable and a preparation method thereof. BACKGROUND

[0002] Industrial kilns, as core thermal equipment in the fields of metallurgy, building materials, chemical industry, ceramics and the like, usually work in an environment with multiple harsh conditions such as high temperature, severe temperature fluctuation, molten material corrosion, airflow scouring and mechanical vibration. The kiln lining material, as a key core for ensuring the safe and stable operation of the kiln and prolonging the service life, directly determines the production efficiency, product quality and operation cost of the kiln. Among many kiln lining materials, castables have gradually replaced traditional refractory bricks and become the mainstream choice for the lining of medium and large industrial kilns due to their advantages such as convenient construction, good integrity and strong adaptability.

[0003] The current industrial kiln castables on the market, although can meet the needs of some conventional working conditions in terms of room temperature strength and basic high temperature resistance, still have two major core defects in complex and harsh actual operating environments: first, the high temperature strength is insufficient, and under the action of long-term high temperature load, the lining structure is prone to deformation and cracking, which leads to the leakage of molten material, and in severe cases, even causes the kiln to shut down for maintenance; second, the anti-thermal shock spalling performance is poor, and the severe temperature changes during the start and stop of the kiln will cause a huge thermal stress in the castable, when the thermal stress exceeds the anti-cracking strength of the material itself, the surface spalling, delamination and even overall collapse phenomenon will easily occur, significantly shortening the service life of the lining material.

[0004] In view of the insufficient high temperature strength performance, the current industry generally improves by increasing the content of high alumina bauxite, corundum and other aggregates to improve the strength of the castable, but this will increase the thermal conductivity of the material and aggravate the thermal stress concentration problem, thereby reducing the anti-spalling performance; in view of the insufficient anti-thermal shock stability, the current industry generally improves by adding organic fibers, metal fibers and the like, but organic fibers are prone to combustion and carbonization to form pores at high temperatures, and metal fibers may lose their reinforcing effect after high temperature oxidation, so it is difficult to achieve a synergistic improvement in strength and anti-spalling performance.

[0005] The Chinese patent application file with the publication number CN111423242A discloses an anti-peeling high thermal shock resistant castable, which is prepared from the following raw materials in parts by weight: glass kiln waste zirconite brick particles and fine powder 40 to 60 parts, waste silicon carbide shelf board particles 15 to 30 parts, fused quartz particles 1 to 10 parts, mullite fine powder 10 to 20 parts, aluminate cement 3 to 15 parts, silicon oxide micro powder 3 to 5 parts, aluminum oxide micro powder 3 to 5 parts, metal silicon powder 1 to 3 parts, one or both of sodium tripolyphosphate or sodium hexametaphosphate 1 to 2 parts. The synthetic material with small thermal expansion coefficient and good thermal shock stability is used to improve the anti-peeling performance and thermal shock resistance of the refractory material. However, the glass kiln waste zirconite brick particles will react with the glass solution during service, which may introduce sodium oxide, calcium oxide and other alkali metal or alkaline earth metal impurities, form a low melting point phase, and the fused quartz particles will undergo crystal transformation at 1100℃ or above, accompanied by volume expansion, resulting in microcracks in the castable, and reducing the erosion resistance of the castable. SUMMARY

[0006] In order to solve the technical problems of insufficient high temperature strength and poor thermal shock peeling resistance in the related art, the present application provides a high-strength anti-peeling industrial kiln castable and a preparation method thereof.

[0007] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0008] A high-strength anti-peeling industrial kiln castable, comprising the following components in parts by weight:

[0009] 80-90 parts of white corundum, 20-40 parts of modified corundum, 35-40 parts of petalite, 30-45 parts of composite micro powder, 10-20 parts of modified micro powder, 20-30 parts of binder, 5-10 parts of sodium hexametaphosphate;

[0010] The preparation method of the modified corundum is as follows: uniformly mix alumina powder and titanium dioxide powder, add polyvinyl alcohol solution and sodium hexametaphosphate for granulation, dry, then sinter at 1200-1300℃ for 2-3h, then heat to 1800℃ and sinter for 4-6h, cool and crush to obtain the modified corundum.

[0011] In the above scheme, white corundum, modified corundum and petalite are used as aggregates of the kiln castable, which has a low expansion coefficient at high temperature, and the composite powder and nano powder are added to fill the gaps of the aggregates to form a dense packing structure, reduce the porosity of the castable and improve the density. Among them, the petalite crystal has a very low thermal expansion coefficient and good compatibility with white corundum and other components, which can promote the formation of a low-expansion glass phase or microcrystalline phase in the matrix, reduce the thermal shock sensitivity of the castable, and avoid spalling caused by sudden temperature changes; the modified corundum is a small amount of titanium dioxide doped in corundum. The ionic radius of titanium ions is close to that of aluminum ions, which can replace aluminum ions in the corundum lattice to form an Al2O3-TiO2 solid solution at high temperature, form a lattice distortion, refine the aggregate grain, increase the grain boundary area, and increase the resistance of the distorted lattice to high-temperature grain boundary sliding, thereby improving the high-temperature compressive strength of the castable and reducing the thermal expansion coefficient of the aggregate.

[0012] Further, in the preparation method of the modified corundum, the mass of the titanium dioxide powder is 1%-2% of the mass of the aluminum oxide powder.

[0013] In the above scheme, the amount of titanium dioxide powder needs to be accurately controlled. A small amount of titanium dioxide doping can refine the grain and improve the high-temperature compressive strength, but excessive doping can precipitate a second phase of titanium oxide in the modified corundum, thereby reducing the high-temperature compressive strength.

[0014] Further, in the preparation method of the modified corundum, the mass percentage of the polyvinyl alcohol solution is 5%-7%, the amount of the polyvinyl alcohol solution is 12%-15% of the mass of the aluminum oxide powder, and the amount of the sodium hexametaphosphate is 0.2%-0.5% of the mass of the aluminum oxide powder.

[0015] Further, in the preparation method of the modified corundum, the heating rate at 1200-1300℃ is 3-5℃ / min, and the heating rate when the temperature rises to 1800℃ is 1-3℃ / min; the specific process of the cooling is that the cooling rate is 2-3℃ / min from 1800-1000℃, and the temperature is cooled to 1000℃.

[0016] In the above scheme, using a faster heating rate can shorten the heating time and improve the sintering rate, and using a slower heating rate after the temperature reaches 1300℃ can avoid lattice defects of the modified corundum. In the cooling process, a slower cooling rate from 1800-1000℃ can avoid lattice stress caused by rapid cooling.

[0017] Further, the composite 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).

[0018] In the above scheme, the white corundum powder, mullite powder, aluminum powder and silicon powder together constitute the composite micro powder can effectively fill the gap between the aggregate, realize multi-level particle packing structure, reduce the porosity. Among them, the white corundum powder and mullite powder cooperatively build high refractoriness matrix, and the low expansion characteristics can endow the matrix with good thermal shock resistance, the white corundum powder can also provide sufficient alumina raw material for mullitization reaction, the aluminum powder and silicon powder have high activity, and will first oxidize or react in the medium-high temperature (800-1200℃) stage to generate ceramic phases such as alumina or silicon nitride to fill the pores and strengthen the grain boundary, realize in-situ toughening and reinforcement, and significantly improve the compressive strength of the castable at high temperature.

[0019] Further, the preparation method of the modified micro powder is as follows: soaking nano-titanium diboride in a nitric acid solution for 2-2.5 h, filtering, washing, and drying to obtain acidified nano-titanium diboride; uniformly mixing tetraethyl orthosilicate and anhydrous ethanol, slowly adding a nitric acid solution, and stirring for 12-15 h to obtain a silica sol; adding the acidified nano-titanium diboride into the silica sol, stirring for 2-4 h, vacuum rotary evaporation at 50-60℃ for 4-6 h, then drying at 80-90℃ for 10-12 h, grinding, passing through a 500-mesh sieve, and heating to 800℃ under a nitrogen atmosphere, and sintering for 2-3 h, and then cooling in the furnace to obtain the modified micro powder.

[0020] In the above scheme, a silica ceramic layer is coated on the surface of the nano-titanium diboride by the sol-gel method to strengthen the interfacial bonding force between the nano-titanium diboride and the matrix. Titanium diboride is a super-hard ceramic phase, which can act as a rigid reinforcing point in the high-temperature use process to hinder the sliding and growth of the grains in the matrix, significantly reduce the high-temperature creep rate of the castable, and improve the high-temperature compressive strength.

[0021] Further, the mass percentage of the nitric acid solution in the preparation method of the modified micro powder 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).

[0022] Further, the particle size of the white corundum is 5-10 mm, the particle size of the modified corundum is 3-5 mm, the particle size of the petalite is 1-3 mm, and the particle size of the composite micro powder is 15-20 μm.

[0023] Further, the binding agent is calcium aluminate cement.

[0024] In the above scheme, the pure calcium aluminate cement generates CA2 and CA6 and other high-melting-point minerals at high temperature, and the strength loss caused by the decomposition of hydration products such as ettringite is avoided.

[0025] The application further provides a preparation method of the high-strength anti-stripping industrial kiln castable, specifically: white corundum, modified corundum, petalite, composite micro powder, modified micro powder, a binder and sodium hexametaphosphate are uniformly mixed to obtain the high-strength anti-stripping industrial kiln castable; when used, water is added into a powerful mixer and uniformly stirred for 5-10 minutes, and then the masonry work can be performed.

[0026] In the above scheme, the dry mixing process is adopted to shorten the production cycle and reduce the equipment and labor costs.

[0027] Compared with the prior art, the high-strength anti-stripping industrial kiln castable and the preparation method thereof have the following technical advantages:

[0028] (1) In the application, the white corundum, the modified corundum and the petalite are used as aggregates of the kiln castable, the composite micro powder and the nano micro powder are added to fill the gaps of the aggregates, and a dense packing structure is formed to reduce the porosity of the castable;

[0029] (2) In the application, the corundum is doped with titanium dioxide to form an Al2O3-TiO2 solid solution, the aggregate grain is refined, the resistance to grain boundary sliding is increased, and the high-temperature compressive strength of the castable is improved;

[0030] (3) In the application, the white corundum powder, the mullite powder, the aluminum powder and the silicon powder are used to form the composite micro powder, which can effectively fill the gaps between the aggregates, realize a multi-level particle packing structure, and reduce the porosity;

[0031] (4) In the application, the sol-gel method is used to coat a layer of silicon oxide ceramic layer on the surface of the nano titanium diboride to strengthen the interfacial bonding force between the nano titanium diboride and the matrix, increase the rigid reinforcement points, and improve the high-temperature compressive strength. DETAILED DESCRIPTION

[0032] The application will be further described below in combination with specific embodiments, but the application is not limited to the following embodiments. Those skilled in the art can make various modifications according to the basic idea of the application, as long as the modifications do not deviate from the basic idea of the application, and the modifications are within the scope of the application.

[0033] The preparation method of the high-strength anti-stripping industrial kiln castable in the embodiment is specifically: white corundum, modified corundum, petalite, composite micro powder, modified micro powder, a binder and sodium hexametaphosphate are uniformly mixed to obtain the high-strength anti-stripping industrial kiln castable; when used, water is added into a powerful mixer and uniformly stirred for 5-10 minutes, and then the masonry work can be performed.

[0034] In the embodiment, the particle size of the white corundum is 5-10 mm, the particle size of the modified corundum is 3-5 mm, the particle size of the petalite is 1-3 mm, and the particle size of the composite micro powder is 15-20 μm.

[0035] Example 1

[0036] A high-strength anti-spalling industrial kiln castable comprises the following components in parts by weight:

[0037] white corundum 80g, modified corundum 20g, petalite 35g, composite micropowder 45g, modified micropowder 20g, calcium aluminate cement 30g, sodium hexametaphosphate 10g;

[0038] The preparation method of the modified corundum is as follows: 100g of aluminum oxide powder and 1g of titanium dioxide powder are uniformly mixed, 12g of a 5% polyvinyl alcohol solution and 0.2g of sodium hexametaphosphate are added for granulation, a green body particle with a particle size of 5mm is prepared, and then the green body particle is dried in a hot air drying oven at 110℃ for 24h, heated to 1200℃ at a heating rate of 3℃ / min and sintered for 2h, then heated to 1800℃ at a heating rate of 1℃ / min and sintered for 4h, and then cooled to 1000℃ at a cooling rate of 2℃ / min, crushed, and the modified corundum is obtained.

[0039] The composite micropowder 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.

[0040] The preparation method of the modified micropowder is as follows: 100g of nanometer titanium diboride is soaked in 200mL of a 3% nitric acid solution for 2h, filtered, washed and dried to obtain acidified nanometer titanium diboride; 100g of tetraethyl orthosilicate is uniformly mixed with 89g of anhydrous ethanol, 55g of a 3% nitric acid solution is slowly added, stirred for 12h, and a silica sol is obtained; the acidified nanometer titanium diboride is added to 30g of the 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, and sintered for 2h, and then cooled in the furnace to obtain the modified micropowder.

[0041] Example 2

[0042] A high-strength anti-spalling industrial kiln castable comprises the following components in parts by weight:

[0043] white corundum 90g, modified corundum 40g, petalite 40g, composite micropowder 30g, modified micropowder 10g, calcium aluminate cement 20g, sodium hexametaphosphate 5g;

[0044] The preparation method of the modified corundum is as follows: 100 g of alumina powder and 2 g of titanium dioxide powder are uniformly mixed, 15 g of a 7% by mass polyvinyl alcohol solution and 0.5 g of sodium hexametaphosphate are added for granulation, a green body particle with a particle size of 15 mm is prepared, the green body particle is placed in a hot air drying oven and dried at 120℃ for 24 h, the temperature is raised to 1300℃ at a temperature raising rate of 5℃ / min and sintered for 3 h, then the temperature is raised to 1800℃ at a temperature raising rate of 3℃ / min and sintered for 6 h, the temperature is lowered to 1000℃ at a temperature lowering rate of 3℃ / min and the furnace is cooled, and the modified corundum is obtained after crushing.

[0045] 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.

[0046] The preparation method of the modified micro powder is as follows: 150 g of nano titanium diboride is soaked in 200 mL of a 5% by mass nitric acid solution for 2.5 h, filtered, washed and dried to obtain acidified nano titanium diboride; 100 g of tetraethyl orthosilicate is uniformly mixed with 92 g of anhydrous ethanol, 61 g of a 5% by mass nitric acid solution is slowly added, and stirring is performed for 15 h to obtain a silica sol; the acidified nano titanium diboride is added to 70 g of the silica sol, stirring is performed for 4 h, vacuum rotary evaporation is performed at 60℃ for 6 h, then drying is performed at 90℃ for 12 h, grinding is performed, the product is sieved through a 500 mesh sieve, the temperature is raised to 500℃ at a rate of 3℃ / min in a nitrogen atmosphere, then the temperature is raised to 800℃ at a rate of 2℃ / min, and the product is sintered for 3 h, and the furnace is cooled to obtain the modified micro powder.

[0047] Example 3

[0048] A high-strength anti-spalling industrial kiln castable comprises the following components in parts by weight:

[0049] White corundum 85 g, modified corundum 30 g, petalite 37 g, composite micro powder 40 g, modified micro powder 15 g, calcium aluminate cement 25 g, and sodium hexametaphosphate 8 g;

[0050] The preparation method of the modified corundum is as follows: 100 g of alumina powder and 1.5 g of titanium dioxide powder are uniformly mixed, 13 g of a 6% by mass polyvinyl alcohol solution and 0.4 g of sodium hexametaphosphate are added for granulation, a green body particle with a particle size of 10 mm is prepared, the green body particle is placed in a hot air drying oven and dried at 115℃ for 24 h, the temperature is raised to 1250℃ at a temperature raising rate of 4℃ / min and sintered for 2.5 h, then the temperature is raised to 1800℃ at a temperature raising rate of 2℃ / min and sintered for 5 h, the temperature is lowered to 1000℃ at a temperature lowering rate of 2.5℃ / min and the furnace is cooled, and the modified corundum is obtained after crushing.

[0051] 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.

[0052] The preparation method of the modified micro powder is as follows: 130 g of nanometer titanium diboride is soaked in 200 mL of 4% nitric acid solution for 2.2 h, filtered, washed, and dried to obtain acidified nanometer titanium diboride; 100 g of tetraethyl orthosilicate is uniformly mixed with 90 g of anhydrous ethanol, and 58 g of 4% nitric acid solution is slowly added and stirred for 14 h to obtain silica sol; the acidified nanometer titanium diboride is added to 45 g of silica sol, stirred for 3 h, vacuum rotary evaporated at 55°C for 5 h, then dried at 85°C for 11 h, ground, sieved through a 500-mesh sieve, and heated to 500°C at a rate of 3°C / min under a nitrogen atmosphere, then heated to 800°C at a rate of 2°C / min, and sintered for 2.5 h, and then cooled in the furnace to obtain the modified micro powder.

[0053] Example 4

[0054] A high-strength anti-spalling industrial kiln castable comprises the following components in parts by weight:

[0055] 88 g of white corundum, 32 g of modified corundum, 38 g of petalite, 39 g of composite micro powder, 16 g of modified micro powder, 25 g of calcium aluminate cement, and 8 g of sodium hexametaphosphate;

[0056] The preparation method of the modified corundum is as follows: 100 g of aluminum oxide powder and 1.6 g of titanium dioxide powder are uniformly mixed, 14 g of 6% polyvinyl alcohol solution and 0.3 g of sodium hexametaphosphate are added for granulation to prepare green body particles with a particle size of 10 mm, the green body particles are placed in a hot air drying oven and dried at 115°C for 24 h, heated to 1250°C at a rate of 4°C / min, sintered for 2.5 h, then heated to 1800°C at a rate of 2°C / min, sintered for 5 h, then cooled to 1000°C at a rate of 2.5°C / min, and then cooled in the furnace to obtain the modified corundum.

[0057] 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.

[0058] The preparation method of the modified micro powder is as follows: 135 g of nanometer titanium diboride is soaked in 200 mL of 4% nitric acid solution for 2.2 h, filtered, washed, and dried to obtain acidified nanometer titanium diboride; 100 g of tetraethyl orthosilicate is uniformly mixed with 90 g of anhydrous ethanol, and 58 g of 4% nitric acid solution is slowly added and stirred for 13 h to obtain silica sol; the acidified nanometer titanium diboride is added to 52 g of silica sol, stirred for 3 h, vacuum rotary evaporated at 55°C for 5 h, then dried at 85°C for 11 h, ground, sieved through a 500-mesh sieve, and heated to 500°C at a rate of 3°C / min under a nitrogen atmosphere, then heated to 800°C at a rate of 2°C / min, and sintered for 2.5 h, and then cooled in the furnace to obtain the modified micro powder.

[0059] Comparative Example 1

[0060] The industrial furnace castable in the present comparative example is similar to that of Example 4, and the difference between the present comparative example and Example 4 is that the present comparative example uses an equal amount of white corundum instead of modified corundum.

[0061] Comparative Example 2

[0062] The industrial furnace castable in the present comparative example is similar to that of Example 4, and the difference between the present comparative example and Example 4 is that the present comparative example uses an equal amount of white corundum instead of petalite.

[0063] Comparative Example 3

[0064] The industrial furnace castable in the present comparative example is similar to that of Example 4, and the difference between the present comparative example and Example 4 is that the present comparative example uses an equal amount of white corundum powder instead of aluminum powder in the composite micropowder.

[0065] Comparative Example 4

[0066] The industrial furnace castable in the present comparative example is similar to that of Example 4, and the difference between the present comparative example and Example 4 is that the present comparative example uses an equal amount of white corundum powder instead of silicon powder in the composite micropowder.

[0067] Comparative Example 5

[0068] The industrial furnace castable in the present comparative example is similar to that of Example 4, and the difference between the present comparative example and Example 4 is that the present comparative example uses an equal amount of nano-titanium diboride instead of modified micropowder.

[0069] Comparative Example 6

[0070] The industrial furnace castable in the present comparative example is similar to that of Example 4, and the difference between the present comparative example and Example 4 is that the present comparative example uses an equal amount of aluminum oxide powder instead of modified micropowder.

[0071] Test Example

[0072] Thermal shock resistance test: The industrial furnace castables prepared in Examples 1-4 and Comparative Examples 1-6 are added to water and stirred, then applied to the test column in a conventional manner, dried, and then tested. The test column is made of graphite carbon fiber cloth material and can withstand a maximum temperature of 2500°C. The thermal shock resistance is expressed as the number of cycles between water cooling and 1400°C that can be withstood.

[0073] Mechanical property test: The compressive strength at room temperature of the castable prepared in Example 1-Example 4, Comparative Example 1-Comparative Example 6 was tested according to GB / T 5072-2023, the compressive strength at high temperature of the castable prepared in Example 1-Example 4, Comparative Example 1-Comparative Example 6 was tested according to GB / T 34218-2025; the flexural strength at room temperature of the refractory prepared in Example 1-Example 4, Comparative Example 1-Comparative Example 6 was tested according to GB / T 3001-2017; the flexural strength at high temperature of the refractory prepared in Example 1-Example 4, Comparative Example 1-Comparative Example 6 was tested according to GB / T 3002-2017.

[0074] The test results are shown in Table 1.

[0075] Table 1 Performance test results

[0076]

[0077] As shown in Table 1, the high-strength anti-spalling industrial furnace castable provided by the present application has a thermal shock resistance of more than 55 times, a compressive strength at room temperature of 120.6-123.6 MPa, a compressive strength at high temperature of 118.5-123.2 MPa, a flexural strength at room temperature of 11.2-12.8 MPa, and a flexural strength at high temperature of 10.3-12.3 MPa, which fully demonstrates that the high-strength anti-spalling industrial furnace castable provided by the present application has good thermal shock resistance and high-temperature mechanical properties.

[0078] The above examples are merely illustrative of the present application and are not intended to limit the present application. Those skilled in the art cannot modify the above examples without departing from the spirit and scope of the present application. All equivalent modifications or changes made by those skilled in the art without departing from the technical idea of the present application still fall within the protection scope of the present application.

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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