A heavy calcium hexaaluminate high-temperature resistant material and its preparation method

Abstract

This application discloses a heavy calcium hexaaluminate high-temperature resistant material and its preparation method, belonging to the technical field of high-temperature resistant materials. The preparation method of the heavy calcium hexaaluminate high-temperature resistant material provided in this application includes the following steps: mixing alumina, calcium carbonate, and a sintering aid to obtain a mixture; adding a binder to the mixture and performing pelletizing treatment to obtain green pellets; the binder is pure water; drying the green pellets; and calcining the dried green pellets in an ultra-high temperature vertical kiln at a calcination temperature of 1760–1810℃, followed by rapid cooling to obtain the heavy calcium hexaaluminate high-temperature resistant material. This application also provides the application of the heavy calcium hexaaluminate high-temperature resistant material in hydrogen metallurgy, which is prepared using the above method. The heavy calcium hexaaluminate high-temperature resistant material of this application has high bulk density, low apparent porosity, and good resistance to reducing atmosphere, slag corrosion, and creep.

Description

Technical Field

[0001] This application belongs to the field of high-temperature resistant materials technology, specifically relating to a heavy calcium hexaaluminate high-temperature resistant material and its preparation method. Background Technology

[0002] Hydrogen, as a clean and pollution-free reducing agent, is increasingly being used in ironmaking processes. Unlike traditional carbon-based reduction, hydrogen reacts with iron oxide or ferrous oxide to produce only water, without generating greenhouse gases such as carbon dioxide. Therefore, it is considered an ideal alternative to carbon in future steel production. With the development of new energy industries and technological advancements, the cost of hydrogen is expected to decrease, further promoting its economic feasibility as a reducing agent.

[0003] Currently, ironmaking processes using carbon as a reducing agent primarily employ refractory materials such as brown corundum, mullite, bauxite, coke, and silicon carbide products. These silica-containing refractory materials exhibit good performance at high temperatures under carbon reducing agent conditions, meeting the requirements of traditional ironmaking processes. However, under hydrogen reducing agent conditions, because hydrogen is a gas, it can be uniformly distributed throughout the blast furnace at the corresponding temperature and participate in the reaction. Furnace linings made of silica-containing refractory materials are easily reduced to elemental silicon by hydrogen at high temperatures, leading to structural damage and a decrease or loss of high-temperature resistance. Furthermore, these materials exhibit high wettability to molten metals and slags (such as iron and steel and non-ferrous metals), accelerating material erosion and shortening their service life.

[0004] Faced with these challenges, a novel refractory material capable of adapting to hydrogen reduction processes and possessing superior performance is particularly important. In this context, calcium hexaaluminate (CA6), due to its excellent chemical stability and low wettability to molten metal and slag, has become an ideal refractory material in hydrogen-reducing ironmaking processes. Furthermore, its coefficient of thermal expansion is close to that of alumina, allowing it to be mixed with alumina in any proportion, enhancing the design flexibility of composite materials.

[0005] Currently, the most common CA6 products on the market have a bulk density of less than 0.8 g / cm³. 3 Lightweight CA6 insulation material with a bulk density of less than 3.1 g / cm³ 3 The existing CA6 is a heavy-duty product, but its bulk density is not high enough, its apparent porosity is relatively large, and its strength is low. It cannot provide sufficient resistance to slag corrosion, creep and wear, and therefore cannot meet the working environment requirements of molten iron or steel ladles.

[0006] Therefore, there is an urgent need to develop a heavy calcium hexaaluminate high-temperature resistant material with good resistance to reducing atmosphere, slag corrosion and creep. Summary of the Invention

[0007] In view of this, this application provides a heavy calcium hexaaluminate high-temperature resistant material and its preparation method. The heavy calcium hexaaluminate high-temperature resistant material provided by this application has high bulk density, low apparent porosity, and good resistance to reducing atmosphere, slag corrosion and creep.

[0008] In a first aspect, this application provides a method for preparing a heavy calcium hexaaluminate high-temperature resistant material, comprising the following steps:

[0009] Step S1: Mix alumina, calcium carbonate, and sintering aid to obtain a mixture;

[0010] Step S2: Add a binder to the mixture and perform a pelletizing process to obtain green pellets; the binder is pure water;

[0011] Step S3: Place the green pellets in a tower dryer for drying. The maximum drying temperature is 300-500℃, and the drying time is 5-12 hours.

[0012] Step S4: The dried green pellets are put into an ultra-high temperature vertical kiln for calcination at a temperature of 1760-1810℃ for 0.5-1.5h. Then, they are rapidly cooled to 800-1000℃ at a cooling rate of 8-10℃ / min to obtain the heavy calcium hexaaluminate high-temperature resistant material.

[0013] By adopting the above technical solution, the preparation method of this application can improve the bulk density of heavy calcium hexaaluminate high-temperature resistant materials and reduce the apparent porosity, thereby enabling the heavy calcium hexaaluminate high-temperature resistant materials to obtain good resistance to reducing atmospheres, slag corrosion, and creep. The prepared heavy calcium hexaaluminate high-temperature resistant materials can be applied in harsh working environments such as hydrogen reduction ironmaking, providing strong support for future low-carbon ironmaking processes.

[0014] In step S1 of this application, the raw materials are uniformly mixed and ground, which promotes the subsequent solid-state reaction process and improves the density of the product. Furthermore, the presence of the sintering aid lowers the sintering temperature while maintaining good density. In step S2, pure water is used as a binder in combination with the alumina raw material. The hydration of the amorphous transition phase alumina in the alumina helps the particles adhere together, forming a stable structure with high mechanical strength, preventing disintegration during drying and calcination. Using pure water as a binder avoids introducing impurities, which helps improve product purity and thus enhances the product's high-temperature resistance. This pre-forming method allows for automatic control, high output, high efficiency, low cost, and control over the particle size distribution of the final product, facilitating the acquisition of an ideal microstructure. The specific drying conditions in step S3 allow excess moisture inside the green pellets to be discharged evenly without causing stress concentration due to excessively rapid surface drying. This helps maintain the integrity of the finished product and reduce apparent porosity. Combined with the specific calcination temperature and appropriate calcination time in step S4, it helps to form a product with high bulk density and low apparent porosity. Rapid cooling preserves a large number of closed pores within the crystals. These tiny and evenly distributed pores enhance the thermal shock stability of the material.

[0015] Optionally, in step S1, the alumina is metallurgical grade alumina with a purity of 99.5% to 99.9%; and the calcium carbonate has a purity of ≥98.5%.

[0016] By adopting the above technical solution, this application selects metallurgical-grade alumina as raw material, fully utilizing the amorphous transition phase alumina contained in metallurgical-grade alumina. Upon contact with moisture, this phase undergoes a hydration reaction, forming a hydrate with a certain degree of adhesion. This characteristic allows the subsequently produced green pellets to possess good mechanical strength, not only meeting the conveying requirements of subsequent processes, but also ensuring high purity means lower impurity content, which reduces the impact of other elements on the material's high-temperature resistance. This application uses a specific type of alumina that better complements calcium carbonate, facilitating the formation of a regular, dense crystal structure during calcination, improving the material's resistance to slag corrosion and creep, and enhancing the performance of the final product. Furthermore, in a hydrogen-reducing atmosphere, the lower impurity level helps maintain the material's chemical stability and prevents unnecessary side reactions.

[0017] Optionally, in step S1, the sintering aid includes at least one of a titanium-containing sintering aid and a barium-containing sintering aid;

[0018] The titanium-containing sintering aid contains 73-75% aluminum oxide, 12-13% calcium oxide, and 13-14% titanium dioxide.

[0019] The barium-containing sintering aid contains 72-74% aluminum oxide, 12-13% calcium oxide, and 14-15% barium carbonate.

[0020] Optionally, in step S1, the content of alumina is 78-80 wt%, the content of calcium carbonate is 11-13 wt%, and the content of sintering aid is 8-10 wt%.

[0021] By adopting the above technical solution, the specific ratio of raw materials in this application achieves a balance of material properties, resulting in higher bulk density, lower apparent porosity, and good resistance to reducing atmosphere, slag corrosion, and creep.

[0022] Using pure water as a binder, the amorphous transition phase of alumina in metallurgical-grade alumina is hydrated to form gibbsite and boehmite gels. This water gradually evaporates in gaseous form between 100°C and 550°C, forming uniform channels within the spherical green body. At 800–900°C, calcium carbonate decomposes to generate solid calcium oxide and gaseous carbon dioxide. The gaseous carbon dioxide escapes through the channels left by the water evaporation, preventing cracking and bursting of the green body. Simultaneously, the newly formed solid calcium oxide exhibits extremely high activity and reacts more readily with alumina to form calcium hexaaluminate. During the high-temperature stage, under the action of sintering aids, densification can be completed quickly, ultimately forming heavy calcium hexaaluminate with 100% CA6 phase purity, high bulk density, and low apparent porosity.

[0023] Optionally, in step S1, the particle size D50 of the mixture is 3.0 to 5.0 μm.

[0024] By adopting the above technical solution, the particle size of the mixture in this application can promote uniform mixing, increase the surface area of ​​the reaction, and thus improve the reaction rate and extent. It also helps to form a dense structure, improving the bulk density and mechanical strength of the material.

[0025] Optionally, in step S2, the content of the binder is 17-20 wt% based on the mass percentage of the mixture.

[0026] By adopting the above technical solution, this application uses pure water as a binder, which does not introduce harmful substances, meets environmental protection requirements, avoids the volatile organic compound emission problems that may arise from traditional organic binders, and also reduces costs. Furthermore, due to the inherent hydration characteristics of metallurgical-grade alumina, using pure water as a binder simplifies the process and reduces potential problems caused by using complex binders.

[0027] Optionally, in step S2, the particle size of the green pellets is 18-30 mm.

[0028] By adopting the above technical solution, the green pellet size of this application helps to achieve more uniform heating during drying and calcination, reducing internal stress and cracks caused by temperature gradients. It also ensures that the green pellets have sufficient mechanical strength to withstand the pressure during transportation and stacking, reducing breakage losses. The specific green pellet size makes it easier for internal gases to escape during calcination, reducing apparent porosity and improving the material's resistance to slag corrosion and creep.

[0029] Optionally, in step S4, the calcination temperature is 1770–1800°C.

[0030] Optionally, the bulk density of the heavy calcium hexaaluminate high-temperature resistant material is 3.4–3.55 g / cm³. 3 Apparent porosity ≤ 8.0%, water absorption ≤ 2.0%.

[0031] By adopting the above technical solutions, the high bulk density, low apparent porosity and water absorption of heavy calcium hexaaluminate high-temperature resistant material can significantly improve the material's resistance to slag corrosion and alkaline environment erosion, and it has good creep resistance and thermal shock resistance, making it suitable for working environments such as hydrogen reduction ironmaking.

[0032] Secondly, this application provides an application of a heavy calcium hexaaluminate high-temperature resistant material in hydrogen metallurgy, wherein the heavy calcium hexaaluminate high-temperature resistant material is prepared by the above-mentioned preparation method.

[0033] By adopting the above technical solution, the heavy calcium hexaaluminate high-temperature resistant material prepared in this application can be directly used as the working lining of a hydrogen metallurgical furnace. Furthermore, the calcium-containing material also has a purifying effect on molten iron and steel, especially on ultra-low carbon steel and clean steel, without contaminating the molten steel.

[0034] The heavy calcium hexaaluminate high-temperature resistant material prepared in this application has high bulk density and low apparent porosity, and exhibits good resistance to reducing atmosphere, slag corrosion and creep. It performs well in hydrogen reducing atmosphere and is an ideal refractory material choice for future steel production, which can contribute to achieving global carbon emission reduction goals.

[0035] In summary, the present invention has at least one of the following beneficial technical effects:

[0036] 1. The preparation method of this application can improve the bulk density of heavy calcium hexaaluminate high-temperature resistant materials, reduce the apparent porosity, and enable heavy calcium hexaaluminate high-temperature resistant materials to obtain good resistance to reducing atmosphere, slag corrosion and creep resistance.

[0037] 2. The heavy calcium hexaaluminate high-temperature resistant material prepared in this application has high bulk density and low apparent porosity, and has good resistance to reducing atmosphere, slag corrosion and creep. It performs well in hydrogen reducing atmosphere and is an ideal refractory material choice for future steel production, which can contribute to achieving global carbon emission reduction goals. Attached Figure Description

[0038] Figure 1 This is a scanning electron microscope image of the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 3;

[0039] Figure 2 The image shows the X-ray diffraction pattern of the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 3. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0041] The inventors of this application discovered in their research on calcium hexaaluminate high-temperature resistant materials that the existing calcium hexaaluminate high-temperature resistant materials have insufficient bulk density and large apparent porosity, which cannot provide sufficient resistance to slag corrosion and creep, nor can they meet the working environment requirements of molten iron ladles or steel ladles.

[0042] To address the aforementioned problems, this application proposes a method for preparing a heavy calcium hexaaluminate high-temperature resistant material, comprising the following steps:

[0043] Step S1: Mix alumina, calcium carbonate, and sintering aid to obtain a mixture;

[0044] Step S2: Add a binder to the mixture and perform a pelletizing process to obtain green pellets; the binder is pure water;

[0045] Step S3: Place the green pellets in a tower dryer for drying. The maximum drying temperature is 300-500℃, and the drying time is 5-12 hours.

[0046] Step S4: The dried green pellets are put into an ultra-high temperature vertical kiln for calcination at a temperature of 1760-1810℃ for 0.5-1.5h. Then, they are rapidly cooled to 800-1000℃ at a cooling rate of 8-10℃ / min to obtain the heavy calcium hexaaluminate high-temperature resistant material.

[0047] This application also provides an application of heavy calcium hexaaluminate high-temperature resistant material in hydrogen metallurgy, wherein the heavy calcium hexaaluminate high-temperature resistant material is prepared by the above-described preparation method.

[0048] The solution of this application will be described below with reference to the following specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available products, and the devices or equipment used are all purchased from conventional market sales channels. Specific Implementation

[0050] Example 1

[0051] This embodiment provides a method for preparing a heavy calcium hexaaluminate high-temperature resistant material, including the following steps:

[0052] Step S1: Mix alumina, calcium carbonate, and sintering aid. By mass percentage, the alumina content is 78 wt%, the calcium carbonate content is 13 wt%, and the sintering aid content is 9 wt%, to obtain a mixture with a particle size D50 of 5.0 μm. The alumina is metallurgical grade alumina with a purity of 99.9%; the calcium carbonate has a purity of 98.5%; and the sintering aid is a titanium-containing sintering aid, in which the alumina content is 73%, the calcium oxide content is 13%, and the titanium dioxide content is 14%.

[0053] Step S2: Add a binder to the mixture and perform pelletizing treatment to obtain green pellets with a particle size of 18 mm; wherein, the binder is pure water; the content of the binder is 20 wt% by mass percentage of the mixture.

[0054] Step S3: Place the green pellets in a tower dryer for drying. The maximum drying temperature is 300℃ and the drying time is 12 hours.

[0055] Step S4: The dried green pellets are put into an ultra-high temperature vertical kiln for calcination at a temperature of 1760℃ for 1.5 hours. Then, they are rapidly cooled to 1000℃ at a cooling rate of 8℃ / min to obtain heavy calcium hexaaluminate high-temperature resistant material.

[0056] Example 2

[0057] This embodiment provides a method for preparing a heavy calcium hexaaluminate high-temperature resistant material, including the following steps:

[0058] Step S1: Mix alumina, calcium carbonate, and sintering aid. By mass percentage, the alumina content is 78 wt%, the calcium carbonate content is 13 wt%, and the sintering aid content is 9 wt%, to obtain a mixture with a particle size D50 of 5.0 μm. The alumina is metallurgical grade alumina with a purity of 99.9%; the calcium carbonate has a purity of 98.5%; and the sintering aid is a titanium-containing sintering aid, in which the alumina content is 73%, the calcium oxide content is 13%, and the titanium dioxide content is 14%.

[0059] Step S2: Add a binder to the mixture and perform pelletizing treatment to obtain green pellets with a particle size of 18 mm; wherein, the binder is pure water; the content of the binder is 18 wt% by mass percentage of the mixture.

[0060] Step S3: Place the green pellets in a tower dryer for drying. The maximum drying temperature is 400℃ and the drying time is 8 hours.

[0061] Step S4: The dried green pellets are put into an ultra-high temperature vertical kiln for calcination at a temperature of 1785℃ for 1 hour, and then rapidly cooled to 900℃ at a cooling rate of 9℃ / min to obtain heavy calcium hexaaluminate high temperature resistant material.

[0062] Example 3

[0063] This embodiment provides a method for preparing a heavy calcium hexaaluminate high-temperature resistant material, including the following steps:

[0064] Step S1: Mix alumina, calcium carbonate, and sintering aid. By mass percentage, the alumina content is 78 wt%, the calcium carbonate content is 13 wt%, and the sintering aid content is 9 wt%, to obtain a mixture with a particle size D50 of 5.0 μm. The alumina is metallurgical grade alumina with a purity of 99.9%; the calcium carbonate has a purity of 98.5%; and the sintering aid is a titanium-containing sintering aid, in which the alumina content is 73%, the calcium oxide content is 13%, and the titanium dioxide content is 14%.

[0065] Step S2: Add a binder to the mixture and perform pelletizing treatment to obtain green pellets with a particle size of 18 mm; wherein, the binder is pure water; the content of the binder is 17 wt% by mass percentage of the mixture.

[0066] Step S3: Place the green pellets in a tower dryer for drying. The maximum drying temperature is 500℃ and the drying time is 5 hours.

[0067] Step S4: The dried green pellets are put into an ultra-high temperature vertical kiln for calcination at a temperature of 1810℃ for 0.5h, and then rapidly cooled to 800℃ at a cooling rate of 10℃ / min to obtain heavy calcium hexaaluminate high temperature resistant material.

[0068] Comparative Example 1

[0069] The difference between Comparative Example 1 and Example 2 is that in step S4 of Comparative Example 1, the calcination temperature is 1700°C.

[0070] Comparative Example 2

[0071] The difference between Comparative Example 2 and Example 2 is that in step S1 of Comparative Example 2, the sintering aid is a titanium-containing sintering aid, in which the content of alumina is 76%, the content of calcium oxide is 14%, and the content of titanium dioxide is 10%.

[0072] Experimental testing

[0073] Testing items and testing methods

[0074] It should be noted that D50 has a well-known meaning in the art, referring to the particle size corresponding to 50% of the particle size distribution, which can be detected according to methods and instruments known in the art. As an example, the detection is performed using the Mastersizer 3000 manufactured by Malvern Corporation in accordance with GB / T 19077-2016.

[0075] Bulk density, apparent porosity, and water absorption were determined according to GB / T 2999-2016, Test Method for Bulk Density of Particles in Refractory Materials, using Method 1: Weighing Method. A DZF-6020 vacuum drying oven manufactured by Shanghai Hongdu Electronic Technology Co., Ltd. was used for vacuuming.

[0076] The bulk density, apparent porosity, and water absorption of the heavy calcium hexaaluminate high-temperature resistant materials prepared in Examples 1-3 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1.

[0077] Table 1

[0078] <![CDATA[Volume density (g / cm 3 )]]> Apparent porosity (%) Water absorption rate (%) Example 1 3.40 5.2 1.5 Example 2 3.48 5.0 1.4 Example 3 3.55 3.0 0.9 Comparative Example 1 3.22 13.1 4.1 Comparative Example 2 3.31 10.2 3.1

[0079] As shown in Table 1, the heavy calcium hexaaluminate high-temperature resistant materials prepared by the method of this application in Examples 1-3 have high bulk density, reaching 3.4-3.55 g / cm³. 3 With an apparent porosity of ≤8.0% and a water absorption rate of ≤2.0%, it exhibits excellent resistance to reducing atmospheres, slag corrosion, and creep.

[0080] The calcination temperature of Comparative Example 1 was 1700℃. The bulk density of the prepared heavy calcium hexaaluminate high-temperature resistant material decreased significantly, while the apparent porosity and water absorption increased significantly.

[0081] In Comparative Example 2, the reduced content of titanium dioxide as a sintering aid resulted in a decrease in the bulk density of the prepared heavy calcium hexaaluminate high-temperature resistant material, while the apparent porosity and water absorption increased.

[0082] Examples 4-11

[0083] Example 4

[0084] The difference between Example 4 and Example 2 is that in step S1 of Example 4, the sintering aid is a barium-containing sintering aid, in which the content of alumina is 73%, the content of calcium oxide is 13%, and the content of barium carbonate is 14%.

[0085] Example 5

[0086] The difference between Example 5 and Example 2 is that in step S1 of Example 5, the sintering aid is a titanium-containing sintering aid and a barium-containing sintering aid with a mass ratio of 1:1.

[0087] The titanium-containing sintering aid contains 74% alumina, 12% calcium oxide, and 14% titanium dioxide.

[0088] The barium-containing sintering aid contains 73% alumina, 13% calcium oxide, and 14% barium carbonate.

[0089] Example 6

[0090] The difference between Example 6 and Example 2 is that in step S1 of Example 6, the raw materials alumina, calcium carbonate, and sintering aid, by mass percentage, have the following contents: alumina content is 79 wt%, calcium carbonate content is 12 wt%, and sintering aid content is 9 wt%.

[0091] Example 7

[0092] The difference between Example 7 and Example 2 is that in step S1 of Example 7, the raw materials alumina, calcium carbonate and sintering aid, by mass percentage, have the following contents: alumina content is 80 wt%, calcium carbonate content is 11 wt%, and sintering aid content is 9 wt%.

[0093] Example 8

[0094] The difference between Example 8 and Example 6 is that in step S1 of Example 8, the particle size D50 of the mixture is 4.0 μm.

[0095] Example 9

[0096] The difference between Example 9 and Example 6 is that in step S1 of Example 9, the particle size D50 of the mixture is 3.0 μm.

[0097] Example 10

[0098] The difference between Example 10 and Example 9 is that in step S2 of Example 10, the particle size of the green pellets is 24 mm.

[0099] Example 11

[0100] The difference between Example 11 and Example 9 is that in step S2 of Example 11, the particle size of the green pellets is 30 mm.

[0101] The bulk density, apparent porosity, and water absorption of the heavy calcium hexaaluminate high-temperature resistant materials prepared in Examples 4-11 were tested, and the test results are shown in Table 2.

[0102] Table 2

[0103] <![CDATA[Apparent density (g / cm 3 )]]> Apparent porosity (%) Water absorption rate (%) Example 4 3.51 4.0 1.2 Example 5 3.53 4.4 1.3 Example 6 3.47 6.5 1.9 Example 7 3.44 6.4 1.9 Example 8 3.48 5.9 1.7 Example 9 3.50 3.9 1.1 Example 10 3.46 4.7 1.4 Example 11 3.43 6.2 1.8

[0104] As can be seen from the test results in Table 2, the difference between Example 4, Example 5 and Example 2 is that the composition of the sintering aid is different. Among them, the apparent porosity and water absorption of the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 4 are lower, while the bulk density of the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 5 is higher.

[0105] The difference between Examples 6 and 7 and Example 2 is that the contents of raw materials alumina, calcium carbonate and sintering aid are different. Among them, the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 6 has a higher bulk density and lower apparent porosity and water absorption.

[0106] The difference between Examples 8 and 9 and Example 6 is that the particle size of the mixture is different. Among them, the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 9 has a higher bulk density and lower apparent porosity and water absorption.

[0107] The difference between Examples 10 and 11 and Example 9 is that the particle size of the green pellets is different. Among them, the heavy calcium hexaaluminate high-temperature resistant material prepared in Example 9 has a higher bulk density and lower apparent porosity and water absorption.

[0108] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a heavy calcium hexaaluminate high-temperature resistant material, characterized in that, Includes the following steps: Step S1: Mix alumina, calcium carbonate, and sintering aid to obtain a mixture; wherein the alumina is metallurgical grade alumina with a purity of 99.5%~99.9%, and the alumina contains an amorphous transition phase alumina; The sintering aid includes at least one of a titanium-containing sintering aid and a barium-containing sintering aid; in the titanium-containing sintering aid, the content of alumina is 73-75%, the content of calcium oxide is 12-13%, and the content of titanium dioxide is 13-14%; in the barium-containing sintering aid, the content of alumina is 72-74%, the content of calcium oxide is 12-13%, and the content of barium carbonate is 14-15%. The alumina content is 78-80 wt%, the calcium carbonate content is 11-13 wt%, and the sintering aid content is 8-10 wt% by weight. Step S2: Add a binder to the mixture and perform a pelletizing process to obtain green pellets; the binder is pure water; Step S3: Place the green pellets in a tower dryer for drying. The maximum drying temperature is 300~500℃ and the drying time is 5~12h. Step S4: The dried green pellets are put into an ultra-high temperature vertical kiln for calcination at a temperature of 1760~1810℃ for 0.5~1.5h, and then rapidly cooled to 800~1000℃ at a cooling rate of 8~10℃ / min to obtain the heavy calcium hexaaluminate high temperature resistant material.

2. The preparation method according to claim 1, characterized in that, In step S1, the purity of the calcium carbonate is ≥98.5%.

3. The preparation method according to claim 1, characterized in that, In step S1, the particle size D50 of the mixture is 3.0~5.0μm.

4. The preparation method according to claim 1, characterized in that, In step S2, the content of the binder is 17-20 wt% based on the mass percentage of the mixture.

5. The preparation method according to claim 1, characterized in that, In step S2, the particle size of the green pellets is 18~30mm.

6. The preparation method according to claim 1, characterized in that, In step S4, the calcination temperature is 1770~1800℃.

7. The preparation method according to claim 1, characterized in that, The bulk density of the heavy calcium hexaaluminate high-temperature resistant material is 3.4~3.55 g / cm³. 3 Apparent porosity ≤ 8.0%, water absorption ≤ 2.0%.

8. The application of a heavy calcium hexaaluminate high-temperature resistant material in hydrogen metallurgy, characterized in that, The heavy calcium hexaaluminate high-temperature resistant material is prepared by the preparation method described in any one of claims 1 to 6.

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