Thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kiln and pouring method

Abstract

The invention relates to a thermal shock resistant high-purity corundum castable for a hydrogen reduction rotary kiln and a pouring method of the thermal shock resistant high-purity corundum castable for the hydrogen reduction rotary kiln. Comprising the following raw materials in parts by weight: 30-40 parts of fused chrome corundum, 20-30 parts of white corundum, 10-20 parts of calcium hexaluminate combined corundum, 5-8 parts of microporous corundum microspheres, 8-12 parts of a filling agent, 1-3 parts of a binding agent, 0.3-0.5 part of a water reducing agent and 4-5 parts of water, and the hydrogen reduction rotary kiln poured by using the castable has a better hydrogen erosion resistance effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory ceramics, and particularly relates to a high-purity corundum castable for hydrogen reduction rotary kiln and a casting method. BACKGROUND

[0002] Sinter and pellet are two most important artificial blocky iron-containing raw materials in modern blast furnace ironmaking process. They are processed into blocky burden with certain strength and uniform particle size through physical and chemical methods, solving the problems of poor permeability and low reduction efficiency caused by direct charging of fine powder.

[0003] The rotary kiln has a diameter of 1.6 meters and a length of 20 meters, is heated by metal electrodes, and has a production and use temperature of 1100 DEG C. The material is sinter and pellet with a particle size of about 10 mm, hydrogen is introduced for reduction, and high-purity direct reduced iron is prepared. The rotary kiln rotates at a speed of 1-4 minutes / revolution, and the filling volume of the sinter and pellet in the rotary kiln is about 50%.

[0004] At 1100 DEG C, hydrogen is used to reduce sinter and pellet, and the castable of the rotary kiln generally contains silicon dioxide and iron oxide. SiO2 and Fe2O3 are reduced by hydrogen to form SiO gas and elemental Fe, which causes the material to be loose and the structural strength to be reduced, affecting the safety and service life of the lining material in the rotary kiln. Therefore, the castable for hydrogen reduction rotary kiln should use high-purity corundum castable without SiO2 and Fe2O3. Considering the factors of feeding and flue gas, the temperature fluctuation in the rotary kiln will cause the castable to be rapidly cooled and heated, resulting in cracking and peeling. Therefore, developing a high-purity corundum castable with good thermal shock resistance and stability is the key to solving the problem of lining of hydrogen reduction rotary kiln. SUMMARY

[0005] The purpose of the present application is to provide a high-purity corundum castable for hydrogen reduction rotary kiln with thermal shock resistance, to solve the technical problem that the material in the hydrogen reduction rotary kiln is easily reduced by hydrogen, causing the material to be loose.

[0006] Another purpose of the present application is to provide a casting method of high-purity corundum castable for hydrogen reduction rotary kiln.

[0007] In order to achieve the above purposes, the technical scheme adopted by the present application is as follows:

[0008] The high-purity corundum castable for hydrogen reduction rotary kiln comprises the following raw materials by weight: 30-40 parts of electrically fused chrome corundum, 20-30 parts of white corundum, 10-20 parts of calcium hexaluminate bonded corundum, 5-8 parts of microporous corundum microspheres, 8-12 parts of filler, 1-3 parts of bonding agent, 0.3-0.5 parts of water reducing agent, and 4-5 parts of water.

[0009] Further, the filler is X12NiCrSi35-16 short fiber.

[0010] Further, the preparation method of the calcium hexaluminate combined corundum is: the alumina base, TiO2 and calcium carbonate are ball milled, calcium lignosulfonate and water are added, and after being uniformly mixed, they are poured into a mold, compacted in the mold, and then dried and sintered, and then crushed into calcium hexaluminate combined corundum particles.

[0011] Further, the mass ratio of the calcium carbonate to the alumina base is 1:12.5-1:13, and the alumina base comprises α-Al2O3 and tabular corundum particles, and the mass ratio of α-Al2O3 to the tabular corundum particles is 3:5-3:6.

[0012] Further, the sintering temperature is 1550-1700°C, and the calcium hexaluminate combined corundum particles are fine aggregates with a particle size of ≤0.088 mm.

[0013] Further, the mass ratio of the calcium carbonate to TiO2 is 1:0.05-1:0.08.

[0014] Further, the particle size of the electro-fused chrome corundum is coarse aggregate with a particle size of 3-1 mm.

[0015] Further, the white corundum is medium aggregate with a particle size of 0.1-1 mm.

[0016] Further, the preparation method of the microporous corundum microspheres comprises the following steps: Y(NO3)3·6H2O and Zr(NO3)4·5H2O are dissolved in water, then urea, white corundum, aluminum powder are added, and then polyvinyl alcohol solution is added, and after granulation, sintering is performed to obtain the microporous corundum microspheres.

[0017] Further, the binder is calcium lignosulfonate, and the water reducing agent is FS10 high-efficiency water reducing agent.

[0018] The pouring method of the above-mentioned hydrogen-reduced thermal shock-resistant high-purity corundum castable for rotary kiln comprises the following steps:

[0019] S1: The formula amount of electro-fused chrome corundum, white corundum, calcium hexaluminate combined corundum, microporous corundum microspheres, filler and binder are dry mixed and uniformly mixed, then water reducing agent and water are added for wet mixing, and after being uniformly mixed, they are poured into a mold and vibrated uniformly, and after being naturally cured at room temperature for 24-48 h, the mold is demolded to obtain an initial setting sample;

[0020] S2: The initial setting sample in step S1 is dried at 110-130°C for 24-48 h, heated at 1350-1400°C for 30-40 min, and then heated at 1200-1250°C in air for 3-4 h, and then naturally cooled to a test sample.

[0021] Advantages of the present application:

[0022] The hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of the present application uses fused chrome corundum, white corundum and calcium hexaluminate combined corundum as main raw materials, contains very low Fe2O3 and SiO2, adds microporous corundum microspheres, which can improve the thermal insulation performance while maintaining the mechanical properties of the kiln. The melting temperature of the filler is lower than the firing temperature. During the firing process, when a small amount of Fe2O3 and SiO2 is reduced, the filler melts and fills the loose structure of the reduced Fe2O3 and SiO2. Then the temperature drops below the melting temperature of the filler, and the pores are sealed after the filler cools down, preventing hydrogen reduction in the rotary kiln from eroding the rotary kiln. In addition, the calcium hexaluminate combined corundum can improve the thermal shock resistance and slag resistance of the rotary kiln. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Photos of samples of Example 1 and Comparative Examples 1-4 after hydrogen corrosion resistance test. DETAILED DESCRIPTION

[0024] The present application will be further described below in conjunction with the examples of the present application and the accompanying drawings.

[0025] Example 1

[0026] The hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of the present embodiment includes the following raw materials: 30g of fused chrome corundum, 25g of white corundum, 15g of calcium hexaluminate combined corundum, 6g of microporous corundum microspheres, 10g of filler, 2g of binder, 0.5g of water reducing agent, and 6g of water.

[0027] The filler is X12NiCrSi35-16 short fiber, and the melting temperature of the X12NiCrSi35-16 short fiber is 1320℃. The length of the short fiber is 9-12mm, and the diameter is 0.22-0.25mm.

[0028] The particle size of the fused chrome corundum is 3-1mm coarse aggregate. The white corundum is a medium aggregate with a particle size of 0.1-1mm.

[0029] The binder is calcium lignosulfonate, and the water reducing agent is FS10 high efficiency water reducing agent. The microporous corundum microspheres are fine powder passing through a 200 mesh sieve.

[0030] The preparation method of the calcium hexaluminate combined corundum is as follows: alumina base, TiO2 and calcium carbonate are ball milled, calcium lignosulfonate and water are added, and then mixed uniformly, poured into a mold, compacted in the mold, and then dried and sintered, and finally crushed into calcium hexaluminate combined corundum particles. The mass ratio of calcium carbonate to alumina base is 1:13, the alumina base includes α-Al2O3 and tabular corundum particles, and the mass ratio of α-Al2O3 to tabular corundum particles is 3:5. The sintering temperature is 1600°C, and the calcium hexaluminate combined corundum particles are fine aggregate with a particle size of ≤0.088 mm. The mass ratio of calcium carbonate to TiO2 is 1:0.05. The mass of calcium lignosulfonate accounts for 3% of the mass of the alumina base, and the mass of water accounts for 5% of the mass of the alumina base.

[0031] The preparation method of the microporous corundum microspheres includes the following steps: 6.3 g of Y(NO3)3·6H2O and 85.5 g of Zr(NO3)4·5H2O are added to 1300 mL of water for dissolution, and then 126 g of urea, 3 g of white corundum, and 3 g of aluminum powder are added, stirred uniformly, dried into a powder at 500°C, 300 mL of a 10% mass fraction polyvinyl alcohol solution is added to the powder, granulated, and then sintered at 1500°C to obtain the microporous corundum microspheres.

[0032] The casting method of the hydrogen-reduced rotary kiln high-purity corundum castable of the embodiment includes the following steps:

[0033] S1: The formula amount of fused chrome corundum, white corundum, calcium hexaluminate combined corundum, microporous corundum microspheres, filler, and binder are dry mixed and uniformly mixed, then water reducing agent and water are added for wet mixing, the mixture is uniformly mixed and vibrated in a mold, and then the mold is demolded after natural curing at room temperature for 24-48 h to obtain an initial setting sample;

[0034] S2: The initial setting sample in step S1 is dried at 110°C for 24 h, heated at 1350°C for 30 min, and then heated at 1200°C in air for 3 h, and then naturally cooled to a test sample.

[0035] Example 2

[0036] The hydrogen-reduced rotary kiln high-purity corundum castable of the embodiment includes the following raw materials: 30 g of fused chrome corundum, 28 g of white corundum, 18 g of calcium hexaluminate combined corundum, 7 g of microporous corundum microspheres, 12 g of filler, 1 g of binder, 0.3 g of water reducing agent, and 5 g of water.

[0037] The filler is X12NiCrSi35-16 short fiber, and the melting temperature of the X12NiCrSi35-16 short fiber is 1350°C. The length of the short fiber is 9-12 mm, and the diameter is 0.22-0.25 mm.

[0038] The grain size of the fused chrome corundum is 3-1mm coarse aggregate. The white corundum is medium aggregate with a grain size of 0.1-1mm.

[0039] The binder is calcium lignosulfonate, and the water reducing agent is FS10 high efficiency water reducing agent. The microporous corundum microspheres are fine powder passing through a 200 mesh sieve.

[0040] The preparation method of the calcium hexaluminate combined corundum is as follows: the alumina base, TiO2 and calcium carbonate are ball milled, calcium lignosulfonate and water are added, and after being uniformly mixed, they are poured into a mold, compacted in the mold, and then dried and sintered, and then crushed into calcium hexaluminate combined corundum particles. The mass ratio of calcium carbonate to alumina base is 1:13, the alumina base includes α-Al2O3 and tabular corundum particles, and the mass ratio of α-Al2O3 to tabular corundum particles is 3:6. The sintering temperature is 1700℃, the calcium hexaluminate combined corundum particles are fine aggregate with a grain size of ≤0.088mm, the mass ratio of calcium carbonate to TiO2 is 1:0.07. The mass of calcium lignosulfonate accounts for 3% of the mass of the alumina base, and the mass of water accounts for 5% of the mass of the alumina base.

[0041] The preparation method of the microporous corundum microspheres includes the following steps: 6.3g of Y(NO3)3·6H2O and 85.5g of Zr(NO3)4·5H2O are added to 1300mL of water to dissolve, and then 126g of urea, 3g of white corundum and 3g of aluminum powder are added, stirred uniformly, dried into powder at 500℃, 300mL of polyvinyl alcohol solution with a mass fraction of 10% is added to the powder, and after granulation, sintering is carried out at 1500℃ to obtain the microporous corundum microspheres.

[0042] The pouring method of the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of the embodiment includes the following steps:

[0043] S1: The formula amount of fused chrome corundum, white corundum, calcium hexaluminate combined corundum, microporous corundum microspheres, filler and binder are dry mixed and uniformly mixed, then the water reducing agent and water are added for wet mixing, and after being uniformly mixed, they are poured into a mold and vibrated uniformly, and after natural curing at room temperature for 24-48h, the mold is demolded to obtain a preliminary setting test sample;

[0044] S2: The preliminary setting test sample in step S1 is dried at 130℃ for 24h, heated at 1400℃ for 30min, and then heated at 1250℃ in air for 3h to obtain a test sample after natural cooling.

[0045] Example 3

[0046] The hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of the embodiment includes the following raw materials: 40g of fused chrome corundum, 20g of white corundum, 20g of calcium hexaluminate combined corundum, 8g of microporous corundum microspheres, 8g of filler, 3g of binder, 0.3g of water reducing agent and 7g of water.

[0047] The filler is X12NiCrSi35-16 short fiber, and the melting temperature of the X12NiCrSi35-16 short fiber is 1350℃. The length of the short fiber is 9-12mm, and the diameter is 0.22-0.25mm.

[0048] The grain size of the electro-fused chrome corundum is coarse aggregate with a grain size of 3-1mm. The white corundum is medium aggregate with a grain size of 0.1-1mm.

[0049] The binder is calcium lignosulfonate, and the water reducing agent is FS10 high efficiency water reducing agent. The microporous corundum microspheres are fine powder passing through a 200 mesh sieve.

[0050] The preparation method of the calcium hexaluminate bonded corundum is as follows: the alumina base, TiO2 and calcium carbonate are ball milled, calcium lignosulfonate and water are added, and after being uniformly mixed, they are poured into a mold, compacted in the mold, and then dried and sintered, and then crushed into calcium hexaluminate bonded corundum particles. The mass ratio of calcium carbonate to alumina base is 1:13, and the alumina base includes α-Al2O3 and tabular corundum particles, and the mass ratio of α-Al2O3 to tabular corundum particles is 3:5. The sintering temperature is 1700℃, the calcium hexaluminate bonded corundum particles are fine aggregate with a particle size of ≤0.088mm, and the mass ratio of calcium carbonate to TiO2 is 1:0.08. The mass of calcium lignosulfonate accounts for 3% of the mass of the alumina base, and the mass of water accounts for 5% of the mass of the alumina base.

[0051] The preparation method of the microporous corundum microspheres includes the following steps: 6.3g of Y(NO3)3·6H2O and 85.5g of Zr(NO3)4·5H2O are added to 1300mL of water to dissolve, and then 126g of urea, 3g of white corundum and 3g of aluminum powder are added, stirred uniformly, dried into powder at 500℃, 300mL of polyvinyl alcohol solution with a mass fraction of 10% is added to the powder, and after granulation, sintering is carried out at 1500℃ to obtain the microporous corundum microspheres.

[0052] The pouring method of the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of the present embodiment includes the following steps:

[0053] S1: The formula amount of electro-fused chrome corundum, white corundum, calcium hexaluminate bonded corundum, microporous corundum microspheres, filler and binder are dry mixed and uniformly mixed, and then water reducing agent and water are added for wet mixing. After being uniformly mixed, they are poured into a mold and vibrated uniformly. After being naturally cured at room temperature for 24-48h, the mold is removed to obtain a preliminary setting test sample;

[0054] S2: The preliminary setting test sample in step S1 is dried at 110℃ for 48h, heated at 1400℃ for 30min, and then heated at 1250℃ in air for 3h. The test sample is naturally cooled to room temperature.

[0055] Example 4

[0056] The high-purity corundum castable for hydrogen reduction rotary kiln of the embodiment comprises the following raw materials: 35 g of fused chrome corundum, 30 g of white corundum, 10 g of calcium hexaluminate bonded corundum, 8 g of microporous corundum microspheres, 10 g of a filler, 2 g of a binder, 0.4 g of a water reducing agent, and 6 g of water.

[0057] The filler is X12NiCrSi35-16 short fiber, and the melting temperature of the X12NiCrSi35-16 short fiber is 1320℃. The length of the short fiber is 9-12 mm, and the diameter is 0.22-0.25 mm.

[0058] The fused chrome corundum has a particle size of 3-1 mm coarse aggregate. The white corundum is medium aggregate with a particle size of 0.1-1 mm.

[0059] The binder is calcium lignosulfonate, and the water reducing agent is FS10 high-efficiency water reducing agent. The microporous corundum microspheres are fine powder passing through a 200-mesh sieve.

[0060] The preparation method of the calcium hexaluminate bonded corundum is as follows: alumina base material, TiO2, and calcium carbonate are ball milled, calcium lignosulfonate and water are added, compaction is performed in a mold, and then drying, sintering, and crushing into calcium hexaluminate bonded corundum particles are performed. The mass ratio of calcium carbonate to alumina base material is 1:12.5, the alumina base material comprises α-Al2O3 and tabular corundum particles, and the mass ratio of α-Al2O3 to tabular corundum particles is 3:6. The sintering temperature is 1550℃, the calcium hexaluminate bonded corundum particles are fine aggregate with a particle size of ≤0.088 mm, the mass ratio of calcium carbonate to TiO2 is 1:0.08. The mass of calcium lignosulfonate accounts for 3% of the mass of the alumina base material, and the mass of water accounts for 5% of the mass of the alumina base material.

[0061] The preparation method of the microporous corundum microspheres comprises the following steps: 6.3 g of Y(NO3)3·6H2O and 85.5 g of Zr(NO3)4·5H2O are added to 1300 mL of water for dissolution, then 126 g of urea, 3 g of white corundum, and 3 g of aluminum powder are added, stirring is uniformly performed, and then drying is performed at 500℃ to obtain a powder, 300 mL of a polyvinyl alcohol solution with a mass fraction of 10% is added to the powder, granulation is performed, and then sintering is performed at 1500℃ to obtain the microporous corundum microspheres.

[0062] The casting method of the high-purity corundum castable for hydrogen reduction rotary kiln of the embodiment comprises the following steps:

[0063] S1: The formula amount of fused chrome corundum, white corundum, calcium hexaluminate bonded corundum, microporous corundum microspheres, a filler, and a binder are dry mixed and uniformly mixed, then a water reducing agent and water are added for wet mixing, and after uniform mixing, the mixture is poured into a mold and vibrated uniformly, and after natural curing at room temperature for 24-48 h, the sample is demolded to obtain a preliminary setting sample;

[0064] S2: The initial setting sample in step S1 is dried at 110℃ for 48h, heated at 1350℃ for 30min, and then heated at 1200℃ in air for 4h, and naturally cooled to the sample to be tested.

[0065] Example 5

[0066] The hydrogen reduction rotary kiln high-thermal shock resistant high-purity corundum castable of the present example comprises the following raw materials: 40kg of fused chrome corundum, 25kg of white corundum, 15kg of calcium hexaluminate bonded corundum, 5kg of microporous corundum microspheres, 10kg of filler, 3kg of binder, 0.5kg of water reducing agent, and 7kg of water.

[0067] The filler is X12NiCrSi35-16 short fiber, and the melting temperature of the X12NiCrSi35-16 short fiber is 1350℃. The length of the short fiber is 9-12mm, and the diameter is 0.22-0.25mm.

[0068] The particle size of the fused chrome corundum is 3-1mm coarse aggregate. The white corundum is medium aggregate with a particle size of 0.1-1mm.

[0069] The binder is calcium lignosulfonate, and the water reducing agent is FS10 high-efficiency water reducing agent. The microporous corundum microspheres are fine powder passing through a 200-mesh sieve.

[0070] The preparation method of the calcium hexaluminate bonded corundum is as follows: alumina base, TiO2, and calcium carbonate are ball milled, calcium lignosulfonate and water are added, and after mixing, the mixture is poured into a mold, compacted in the mold, and then dried and sintered, and then crushed into calcium hexaluminate bonded corundum particles. The mass ratio of calcium carbonate to alumina base is 1:12.5, and the alumina base comprises α-Al2O3 and tabular corundum particles, and the mass ratio of α-Al2O3 to tabular corundum particles is 3:6. The sintering temperature is 1700℃, the calcium hexaluminate bonded corundum particles are fine aggregate with a particle size of ≤0.088mm, and the mass ratio of calcium carbonate to TiO2 is 1:0.06. The mass of calcium lignosulfonate accounts for 3% of the mass of the alumina base, and the mass of water accounts for 5% of the mass of the alumina base.

[0071] The preparation method of the microporous corundum microspheres comprises the following steps: 6.3g of Y(NO3)3·6H2O and 85.5g of Zr(NO3)4·5H2O are added to 1300mL of water to dissolve, and then 126g of urea, 3g of white corundum, and 3g of aluminum powder are added, stirred uniformly, dried into a powder at 500℃, 300mL of a 10% by mass polyvinyl alcohol solution is added to the powder, granulated, and sintered at 1500℃ to obtain the microporous corundum microspheres.

[0072] The casting method of the hydrogen reduction rotary kiln high-thermal shock resistant high-purity corundum castable of the present example comprises the following steps:

[0073] S1: A formula amount of electrically fused chrome corundum, white corundum, calcium hexaluminate bonded corundum, microporous corundum microspheres, a filler, and a binder are dry mixed and uniformly mixed, then a water reducing agent and water are added for wet mixing, and after uniform mixing, the mixture is poured into a mold and vibrated uniformly. After natural curing at room temperature for 24-48 h, the sample is demolded to obtain a preliminary setting sample;

[0074] S2: The preliminary setting sample in step S1 is dried at 110°C for 48 h, heated at 1400°C for 40 min, and then heated at 1250°C in air for 3 h, and then naturally cooled to a sample to be tested.

[0075] Comparative Example 1

[0076] The hydrogen reduction rotary kiln high-purity corundum castable of the present comparative example is substantially the same as that of Example 1, except that the calcium hexaluminate bonded corundum is replaced with an equal amount of tabular corundum particles.

[0077] Comparative Example 2

[0078] The hydrogen reduction rotary kiln high-purity corundum castable of the present comparative example is substantially the same as that of Example 1, except that the microporous corundum microspheres are omitted, and an equal amount of the filler, i.e., X12NiCrSi35-16 short fibers, is used to replace the omitted microporous corundum microspheres.

[0079] Comparative Example 3

[0080] The hydrogen reduction rotary kiln high-purity corundum castable of the present comparative example is substantially the same as that of Example 1, except that the filler X12NiCrSi35-16 short fibers are omitted, and an equal amount of microporous corundum microspheres is used to replace the omitted filler.

[0081] Comparative Example 4

[0082] The hydrogen reduction rotary kiln high-purity corundum castable of the present comparative example is substantially the same as that of Example 1, except that the step of heating at 1350°C for 30 min is omitted during pouring.

[0083] Test Example 1

[0084] Thermal shock resistance test: The samples to be tested of Example 1 and Comparative Examples 1-4 are placed in an electric resistance furnace and heated at 1100°C for 20 min, taken out and rapidly cooled in cold water for 5 min, placed in air for 5 min, and then placed in the electric resistance furnace again and heated, and the above process is repeated 10 times. The thermal shock resistance of the samples to be tested of the hydrogen reduction rotary kiln high-purity corundum castables of Example 1 and Comparative Examples 1-4 is determined. The test results are shown in Table 1.

[0085] Test Example 2

[0086] The content of SiO2 and Fe2O3 in the sample to be tested prepared from the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of Example 1 and Comparative Examples 1-4 is determined. The test results are shown in Table 1.

[0087] Test Example 3

[0088] The hydrogen corrosion resistance of the sample prepared from the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of Example 1 and Comparative Examples 1-4 is determined. The sample prepared from the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of Example 1 and Comparative Examples 1-4 is heat treated at 500°C for 24h under an atmosphere of 35% hydrogen and 65% argon, and the weight change of the sample is determined. The test results are shown in Table 1, and the sample photos after the test are shown in Figure 1

[0089] Table 1 Test results of the properties of the sample to be tested prepared from the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of Example 1 and Comparative Examples 1-4

[0090]

[0091]

[0092] As can be seen from Table 1, the hydrogen reduction rotary kiln prepared from the hydrogen reduction rotary kiln heat shock resistant high-purity corundum castable of the present application has good heat shock resistance and mechanical properties, low content of iron oxide and silicon dioxide, and good corrosion resistance.​

Claims

1. A thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns, characterized in that, The raw materials include the following parts by weight: 30-40 parts of fused chromium corundum, 20-30 parts of white corundum, 10-20 parts of calcium hexaaluminate bonded corundum, 5-8 parts of microporous corundum microspheres, 8-12 parts of filler, 1-3 parts of binder, 0.3-0.5 parts of water-reducing agent, and 4-5 parts of water.

2. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 1, characterized in that, The filler is X12NiCrSi35-16 short fiber.

3. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 1, characterized in that, The preparation method of the calcium hexaaluminate-bonded corundum is as follows: alumina base material, TiO2 and calcium carbonate are ball-milled, calcium lignosulfonate and water are added, mixed and poured into a mold, compacted in the mold, then dried and sintered, and then crushed into calcium hexaaluminate-bonded corundum particles.

4. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 3, characterized in that, The mass ratio of calcium carbonate to alumina base material is 1:12.5 to 1:13, and the alumina base material includes α-Al2O3 and tabular corundum particles, with the mass ratio of α-Al2O3 to tabular corundum particles being 3:5 to 3:

6.

5. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 3, characterized in that, The sintering temperature is 1550–1700℃, and the calcium hexaaluminate-bonded corundum particles are fine aggregates with a particle size ≤0.088mm.

6. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 3, characterized in that, The mass ratio of calcium carbonate to TiO2 is 1:0.05 to 1:0.

08.

7. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 1, characterized in that, The electrofused chromium corundum is a coarse aggregate with a particle size of 3-1 mm.

8. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 1, characterized in that, The method for preparing the microporous corundum microspheres includes the following steps: dissolving Y(NO3)3·6H2O and Zr(NO3)4·5H2O in water, then adding urea, white corundum, and aluminum powder, followed by adding polyvinyl alcohol solution, granulating, and sintering to obtain the microspheres.

9. The thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns according to claim 1, characterized in that, The binder is calcium lignosulfonate, and the water-reducing agent is FS10 high-efficiency water-reducing agent.

10. The casting method for thermal shock resistant high-purity corundum castable for hydrogen reduction rotary kilns as described in claim 1, characterized in that, Includes the following steps: S1: Dry mix the formulated amounts of fused chromium corundum, white corundum, calcium hexaaluminate-bonded corundum, microporous corundum microspheres, filler and binder, then add water-reducing agent and water for wet mixing. After mixing, pour into a mold and vibrate evenly. After curing naturally at room temperature for 24-48 hours, demold to obtain the initial set sample. S2: Dry the initial solidified sample from step S1 at 110-130℃ for 24-48 hours, heat it at 1350-1400℃ for 30-40 minutes, then heat it in air at 1200-1250℃ for 3-4 hours, and then let it cool naturally to the test sample.

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