Multi-oxide composite corundum-based heat-absorbing ceramic and preparation method thereof

Abstract

The present application relates to a kind of polyoxides composite corundum base heat-absorbing ceramic and its preparation method, by mass parts, including the following raw materials: 80~95 bauxite, 8~10 parts of iron oxide, 0.4~1 part of titanium oxide, 6~8 parts of copper oxide, 1~5 parts of additive;Additive includes at least one of lanthanide metal oxide, transition metal oxide and post-transition metal oxide.The present application uses bauxite, iron oxide, titanium oxide, copper oxide and additive as raw material, and the raw material bauxite used is cheap, but its proportion is more than 75%, thus effectively reducing cost;By introducing additive, and under the cooperation of iron oxide, titanium oxide, copper oxide, the absorption rate of the heat-absorbing ceramic formed is high, and the bending strength is good;Excellent high-temperature performance, simple preparation process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar thermal power generation heat-absorbing materials, and particularly relates to a multi-oxide composite corundum-based heat-absorbing ceramic and a preparation method thereof. BACKGROUND

[0002] Large-scale utilization of solar energy is an important way to alleviate the shortage of fossil fuels. Among them, tower type solar thermal power generation has the characteristics of high light concentration ratio and high power generation efficiency, and is considered to be the most promising and potential solar energy development and utilization technology. Receiver materials, as a core component of tower type solar thermal power generation, are required to have high absorption rate and excellent high-temperature performance.

[0003] The currently widely used receiving material is silicon carbide and its composite material with aluminum nitride. For example, Chinese patent CN111269015A discloses a densified mullite-corundum-SiC solar thermal power generation composite heat storage ceramic material and a preparation method thereof, and provides a ceramic heat storage material taking mullite / corundum / SiC as the main crystal phase. The ceramic material prepared has high density and mechanical properties, and the bulk density and bending strength can reach 2.30 g·cm -3 and 77.05 MPa, respectively. Chinese patent CN111253158A discloses a solar thermal power generation heat-absorbing / heat-storing corundum / SiC ceramic material and a preparation method thereof, and provides a ceramic heat-absorbing material taking corundum / SiC as the main crystal phase, with an absorption rate of 91% and a bending strength of 76 MPa to 85 MPa. However, they have problems such as poor oxidation resistance, high cost of synthesized materials, and complex process.

[0004] Oxide-based ceramic materials such as aluminum oxide have attracted more and more attention due to their high thermal oxidation resistance, low processing cost and excellent mechanical properties. For example, Chinese patent CN107140964A discloses a solar heat-absorbing ceramic material with high high-temperature oxidation resistance and a preparation method thereof, and provides a solar heat-absorbing ceramic material with high high-temperature oxidation resistance, which increases the content of magnesium oxide, sodium silicate and aluminum oxide, which has a significant effect on improving the high-temperature oxidation resistance of the material. However, the cost of using aluminum oxide as a raw material is high, and the use of aluminum-containing raw materials such as bauxite as a raw material for preparing heat-absorbing ceramics has problems such as low absorption rate and significant performance degradation at high temperature. SUMMARY

[0005] The present application aims to overcome the above technical deficiencies and provide a multi-oxide composite corundum-based heat-absorbing ceramic and a preparation method thereof, which solves the technical problems of low absorption rate and performance degradation at high temperature of heat-absorbing ceramics prepared by using bauxite as a raw material in the prior art.

[0006] To achieve the above technical purpose, the technical solution provided by the present application is:

[0007] In a first aspect, the present application provides a multi-oxide composite corundum-based heat-absorbing ceramic, comprising the following raw materials in parts by mass: 80-95 parts of bauxite, 8-10 parts of iron oxide, 0.4-1 part of titanium oxide, 6-8 parts of copper oxide, and 1-5 parts of an additive; the additive comprises at least one of lanthanide metal oxides, transition metal oxides, and post-transition metal oxides.

[0008] In a second aspect, the present application provides a preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic, comprising the following steps: S1, uniformly mixing bauxite, iron oxide, titanium oxide, copper oxide, and an additive in a proportion to obtain a mixed powder; S2, adding an organic binder to the mixed powder for granulation, and then performing aging and compression molding to obtain a green body; and S3, drying the green body and then performing sintering to obtain the multi-oxide composite corundum-based heat-absorbing ceramic.

[0009] Compared with the prior art, the present application has the following beneficial effects:

[0010] The multi-oxide composite corundum-based heat-absorbing ceramic of the present application uses bauxite, iron oxide, titanium oxide, copper oxide, and an additive as raw materials, and the bauxite used is inexpensive, but its proportion is more than 75%, thus effectively reducing the cost; by introducing the additive and in combination with iron oxide, titanium oxide, and copper oxide, the heat-absorbing ceramic formed has high absorption rate and good bending strength; has excellent high-temperature resistance, and after 100h high-temperature service (1000℃), the absorption rate can still reach 91.7-92.5%, and the bending strength is maintained at 105.99-121.69 MPa; and the preparation process is simple. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is the XRD pattern of the multi-oxide composite corundum-based heat-absorbing ceramic in Example 3 of the present application;

[0012] Figure 2 is the SEM pattern of the multi-oxide composite corundum-based heat-absorbing ceramic in Example 3 of the present application. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0014] The present application provides a low-cost long-life multi-oxide composite corundum-based heat-absorbing ceramic and a preparation method thereof, which are used to solve the technical problems of low absorption rate and performance degradation during high-temperature service of the existing heat-absorbing ceramic prepared by using bauxite as a raw material.

[0015] In a first aspect, the present application provides a multi-oxide compound corundum-based heat-absorbing ceramic, comprising the following raw materials in parts by mass: 80-95 parts of bauxite, 8-10 parts of iron oxide, 0.4-1 part of titanium oxide, 6-8 parts of copper oxide, and 1-5 parts of an additive; the additive comprises at least one of lanthanide metal oxides, transition metal oxides, and post-transition metal oxides.

[0016] Preferably, the additive comprises lanthanum oxide, praseodymium oxide, cobalt oxide, or tin oxide.

[0017] Preferably, the composition of the bauxite comprises, in percentage by mass: 10-11 wt% of SiO2; 80-81 wt% of Al2O3; 0.1-1 wt% of CaO; 1-2 wt% of Fe2O3; 3-4 wt% of TiO2; 0.1-1 wt% of MgO; 0.1-1 wt% of K2O; 0.01-0.1 wt% of Na2O; and 1-2% of loss on ignition.

[0018] Preferably, the main crystal phase of the heat-absorbing ceramic comprises corundum phase, and the secondary crystal phase comprises iron titanate, spinel, and quartz phase; the spinel comprises hercynite phase (when the additive is lanthanum oxide, praseodymium oxide, and tin oxide) or copper-cobalt spinel phase (when the additive is cobalt oxide).

[0019] In a second aspect, the present application provides a method for preparing a multi-oxide compound corundum-based heat-absorbing ceramic, comprising the following steps:

[0020] S1, uniformly mixing bauxite, iron oxide, titanium oxide, copper oxide, and an additive in a certain proportion to obtain a mixed powder;

[0021] S2, adding an organic binder to the mixed powder to granulate, and then aging and compression molding to obtain a green body;

[0022] S3, drying the green body and then sintering to obtain a multi-oxide compound corundum-based heat-absorbing ceramic.

[0023] Preferably, in step S1, the bauxite, iron oxide, titanium oxide, copper oxide, and additive are uniformly mixed by ball milling.

[0024] Further preferably, the ball milling is performed until the particle size of the powder is ≥250 mesh.

[0025] Preferably, in step S2, the amount of the organic binder added is 5-9% of the mass of the mixed powder; and the organic binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4-6%.

[0026] Preferably, in step S3, the aging condition comprises aging at 25-30℃ for 24-48h.

[0027] Preferably, in step S3, the compression molding is performed at a pressure of 30-50kN.

[0028] Preferably, in step S4, the drying is performed at 80-90℃ for 24-48h.

[0029] Preferably, in step S4, the sintering is performed at 1320-1400℃ for 1-2h.

[0030] Preferably, in step S4, the sintering is performed at a heating rate of 3-5℃ / min.

[0031] The present application is further illustrated in detail by the following specific examples. The bauxite used in the examples has the following composition in terms of mass percentage: SiO2: 10.72wt%; Al2O3: 80.56wt%; CaO: 0.87wt%; Fe2O3: 1.5wt%; TiO2: 3.86wt%; MgO: 0.3wt%; K2O: 0.45wt%; Na2O: 0.06wt%; and loss on ignition: 1.68%.

[0032] In the test, the volume density (D) of the sample is determined by the drainage method according to the Archimedes principle. Specifically, the sample is soaked in a vacuum environment for 30min using a TXY digital ceramic water absorption tester from Xiangtan Xiangyi Instrument Co., Ltd. to make the sample reach a water absorption saturation state. The water absorption saturated sample is soaked in water, and the specific gravity meter is used to measure the sample mass M2 (suspended weight). The sample is taken out of the immersion liquid, and the saturated water absorption towel is used to wipe off the liquid beads on the surface of the saturated sample, and then the sample mass M3 (wet weight) is measured. The specific calculation formula is as follows:

[0033] (1)

[0034] In the formula, D is the volume density, g / cm 3 ; D1 is the density of the immersion liquid, g / cm 3 ; and D2 is the density of the sample, g / cm 3 .

[0035] The three-point bending method (referring to the national standard GB5101-2003) is used to test the bending strength of the sample by using an electronic universal testing machine (model RGM-4100) at a loading speed of 0.5 mm / min. The bending strength of the sample is obtained by the following calculation formula (2):

[0036] (2)

[0037] In the formula, σ b- the flexural strength of the sample, MPa; P - the load at the time of sample fracture, N; L - the knife edge distance used to support the sample, mm; K - the lever arm ratio, the value of this model instrument is 1; B - the width of the sample at the fracture location, mm; H - the thickness of the sample at the fracture location, mm.

[0038] The reflectivity of the sample is tested by using a UV-visible-near infrared spectrophotometer (model UV-3600), and the solar absorption rate is obtained by the following calculation formula (3):

[0039] (3)

[0040] In the formula: αs - the solar absorption rate of the sample, %; λ - wavelength, μm; ρ s (λ) - reflectivity, %; E s (λ) - solar radiation intensity, W.

[0041] The high-temperature service experiment process is as follows: after the sintered sample is placed in a durable electric furnace, the resistance furnace is heated to 1000 ℃ at a rate of 5 ℃ / min, and after 10 h of heat preservation, the furnace is cooled to room temperature, and the sample is taken out to complete the first durability process. According to the above process, a total of 100 h of heat preservation is carried out, and the solar absorption rate and the change of the flexural strength of the sample are used to characterize the high-temperature stability. The flexural strength is tested, and the strength loss rate is used as a characterization, which can be obtained by formula (4):

[0042] (4)

[0043] In the formula: σ0 - the flexural strength of the sample after n times of durability (MPa), n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; S n - the flexural strength of the sample after n times of durability (MPa), n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; S σ - the strength loss rate (%).

[0044] Example 1

[0045] A preparation method of a multi-oxide composite corundum-based heat-absorbing ceramic comprises the following steps:

[0046] S1, 90 parts of bauxite, 9.5 parts of iron oxide, 0.5 parts of titanium oxide, 7 parts of copper oxide and 3 parts of an external additive are placed in a ball mill to obtain a mixed powder with a particle size of 250 μm; wherein the external additive is lanthanum oxide;

[0047] S2, 7wt% of the mixed powder is added to the mixed powder to obtain a mixed powder with a particle size of 250 μm; wherein the external additive is lanthanum oxide;

[0048] S3, the green body is placed in a constant temperature drying oven and dried at 90℃ for 24h; the dried body is placed in a high temperature electric furnace and heated to 1360℃ at a heating rate of 3-5℃ / min for 2h to obtain the polyoxide composite corundum-based heat-absorbing ceramic.

[0049] It is found through testing that the low-cost long-life polyoxide composite corundum-based heat-absorbing ceramic sample prepared in the embodiment 1 has an absorption rate of 93.4 %, a bending strength of 123.78MPa, and a bulk density of 3.65 g / cm 3 After 100h high-temperature service (1000℃), the absorption rate of the sample is 92.0 %, which is 1.4 % lower than before high-temperature service. After 100h high-temperature service (1000℃), the bending strength of the sample is 107.37MPa, which is 13.2 % lower than before high-temperature service.

[0050] Embodiment 2

[0051] The difference from the embodiment 1 is that the additive in the raw material is adjusted to praseodymium oxide, and other steps and conditions are the same as those in the embodiment 1.

[0052] It is found through testing that the low-cost long-life polyoxide composite corundum-based heat-absorbing ceramic sample prepared in the embodiment 2 has an absorption rate of 93.1 %, a bending strength of 113.3MPa, and a bulk density of 3.63 g / cm 3 After 100h high-temperature service (1000℃), the absorption rate of the sample is 91.7 %, which is 1.4 % lower than before high-temperature service. After 100h high-temperature service (1000℃), the bending strength of the sample is 105.99MPa, which is 6.4 % lower than before high-temperature service.

[0053] Embodiment 3

[0054] The difference from the embodiment 1 is that the additive in the raw material is adjusted to cobalt oxide, and other steps and conditions are the same as those in the embodiment 1.

[0055] It is found through testing that the low-cost long-life polyoxide composite corundum-based heat-absorbing ceramic sample prepared in the embodiment 3 has an absorption rate of 93.1 %, a bending strength of 113.09MPa, and a bulk density of 3.58 g / cm 3 After 100h high-temperature service (1000℃), the absorption rate of the sample is 92.5 %, which is 0.6 % lower than before high-temperature service. After 100h high-temperature service (1000℃), the bending strength of the sample is 121.69MPa, which is 7.6 % higher than before high-temperature service.

[0056] Embodiment 4

[0057] The difference from Example 1 is that the additive in the raw material is tin oxide, and other steps and conditions are the same as those in Example 1.

[0058] It is found through testing that the low-cost long-life multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in Example 4 has an absorption rate of 93.2%, a bending strength of 132.44 MPa, and a bulk density of 3.66 g / cm 3 After 100 h of high-temperature service (1000℃), the absorption rate of the sample is 92.4%, which is 0.8% lower than before high-temperature service. After 100 h of high-temperature service (1000℃), the bending strength of the sample is 117.65 MPa, which is 11.1% lower than before high-temperature service.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that the additive in the raw material is tin oxide, and other steps and conditions are the same as those in Example 1.

[0061] It is found through testing that the low-cost long-life multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in Example 4 has an absorption rate of 93.2%, a bending strength of 132.44 MPa, and a bulk density of 3.66 g / cm

[0062] Comparative Example 2

[0063] The difference from Example 1 is that the additive in the raw material is tin oxide, and other steps and conditions are the same as those in Example 1.

[0064] It is found through testing that the low-cost long-life multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in Example 4 has an absorption rate of 93.2%, a bending strength of 132.44 MPa, and a bulk density of 3.66 g / cm

[0065] Comparative Example 3

[0066] The difference from Example 1 is that the additive in the raw material is tin oxide, and other steps and conditions are the same as those in Example 1.

[0067] It is found through testing that the low-cost long-life multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in Example 4 has an absorption rate of 93.2%, a bending strength of 132.44 MPa, and a bulk density of 3.66 g / cm

[0068] Comparative Example 4

[0069] The difference from Example 2 is that the additive in the raw material is tin oxide, and other steps and conditions are the same as those in Example 2.

[0070] It is found through testing that the low-cost long-life multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in Example 4 has an absorption rate of 93.2%, a bending strength of 132.44 MPa, and a bulk density of 3.66 g / cm

[0071] Comparative Example 5

[0072] The difference from Example 2 is only that the amount of the additive in the raw materials is adjusted to 5 parts, and other steps and conditions are the same as those of Example 2.

[0073] It is found through testing that the sample of the corundum-based heat-absorbing ceramic prepared in Comparative Example 5 has an absorption rate of 92.5% and a bending strength of 118.64 MPa.

[0074] Comparative Example 6

[0075] The difference from Example 3 is only that the amount of the additive in the raw materials is adjusted to 1 part, and other steps and conditions are the same as those of Example 3.

[0076] It is found through testing that the sample of the corundum-based heat-absorbing ceramic prepared in Comparative Example 6 has an absorption rate of 91.5% and a bending strength of 112.44 MPa.

[0077] Comparative Example 7

[0078] The difference from Example 3 is only that the amount of the additive in the raw materials is adjusted to 5 parts, and other steps and conditions are the same as those of Example 3.

[0079] It is found through testing that the sample of the corundum-based heat-absorbing ceramic prepared in Comparative Example 7 has an absorption rate of 92.3% and a bending strength of 108.44 MPa.

[0080] Comparative Example 8

[0081] The difference from Example 4 is only that the amount of the additive in the raw materials is adjusted to 1 part, and other steps and conditions are the same as those of Example 4.

[0082] It is found through testing that the sample of the corundum-based heat-absorbing ceramic prepared in Comparative Example 8 has an absorption rate of 92.1% and a bending strength of 122.42 MPa.

[0083] Comparative Example 9

[0084] The difference from Example 4 is only that the amount of the additive in the raw materials is adjusted to 5 parts, and other steps and conditions are the same as those of Example 4.

[0085] It is found through testing that the sample of the corundum-based heat-absorbing ceramic prepared in Comparative Example 9 has an absorption rate of 92.3% and a bending strength of 136.62 MPa.

[0086] In the application of tower type solar thermal power generation, the absorption rate of the corundum-based heat-absorbing ceramic directly affects the light-heat conversion efficiency of the thermal power generation system, and the absorption rate is a key performance of the heat-absorbing material.

[0087] The optimal additive amount for improving the absorption rate was explored by setting three different additive amount gradients for the four additives, and performing Examples 1-4 and Comparative Examples 2-9. The test results show that the absorption rate of each additive amount of 3 parts (Examples 1-4) is higher than that of 1 part and 5 parts (Comparative Examples 2-9), for example, the absorption rate of Comparative Example 8 is 92.1, the absorption rate of Comparative Example 9 is 92.3, the absorption rate of Example 4 is 93.2, the absorption rate of Example 4 is much higher than that of Comparative Examples 8 and 9, and each example is much higher than the absorption rate of the sample without adding the additive.

[0088] When the heat-absorbing ceramic is used in a tower type solar thermal power generation system, in addition to having a high solar light absorption rate, it should also have excellent high temperature resistance. Therefore, Examples 1-4 were selected for high temperature service experiments. The properties of the heat-absorbing ceramic obtained in each of the above examples were statistically analyzed, and the results are shown in Table 1.

[0089] Table 1 Properties of heat-absorbing ceramic obtained in each example

[0090]

[0091] As can be seen from the comparison of Examples 1-4 and Comparative Example 1, the introduction of the additive improves the absorption rate and the bending strength of the corundum-based heat-absorbing ceramic. And from the comparison of Examples 1-4, it can be seen that Example 3 has excellent high temperature service performance, and after 100h high temperature service (1000℃), the absorption rate is 92.5% (only decreased by 0.6%), and the bending strength is 121.69MPa (increased by 7.6%). Therefore, the performance of the additive cobalt oxide in the present application is the best.

[0092] Figure 1 The XRD pattern of the multi-oxide composite corundum-based heat-absorbing ceramic provided in Example 3 of the present application is shown in Figure 1. Figure 1 As can be seen from Figure 1, the main crystal phase of the multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in the present application is corundum phase, and the secondary crystal phase is iron titanate, copper-cobalt spinel and quartz phase.

[0093] Figure 2 The SEM pattern of the multi-oxide composite corundum-based heat-absorbing ceramic provided in Example 3 of the present application is shown in Figure 2. Figure 2 As can be seen from Figure 2, the multi-oxide composite corundum-based heat-absorbing ceramic sample prepared in the present application is distributed with aggregated spherical small particles, which are copper-cobalt spinel grains. For transition metal ions Co 3+ , in the O 2- tetrahedral coordination field, Co 3+The electronic energy level of Co2O3 makes the transition absorption band generally appear in the near ultraviolet and visible light region. In addition, the introduction of Co2O3 makes more defects exist in the sample, forming impurity energy levels, thereby reducing the band gap, reducing the energy required for electrons to transition from the valence band to the conduction band, widening the light absorption range of the sample, and improving the solar absorption rate of the sample. During high-temperature service, thermal energy drives copper ions into the crystal lattice, and the sample forms more copper-cobalt spinel under the action of Co2O3. The generation of copper-cobalt spinel makes the d orbit of Co 3+ split into orbits with different energies in the tetrahedral coordination field, and the electronic energy level of Co 3+ still exists, so the absorption rate of the sample after high-temperature service does not show a large decrease.

[0094] The multi-oxide composite corundum-based heat-absorbing ceramic of the present application uses bauxite, iron oxide, titanium oxide, copper oxide and an external additive as raw materials, and the proportion of bauxite is more than 75%, effectively reducing the cost; by introducing an external additive and cooperating with iron oxide, titanium oxide and copper oxide, the absorption rate (93.1-93.4%) and the bending strength (113.09-132.44 MPa) of the obtained corundum-based heat-absorbing ceramic are effectively improved; and the obtained multi-oxide composite corundum-based heat-absorbing ceramic has excellent high-temperature resistance, and after 100h high-temperature service (1000℃), the absorption rate can still reach 91.7-92.5%, and the bending strength is 105.99-121.69 MPa; therefore, the raw materials used in the present application are low in price, the material prepared has high absorption rate, excellent high-temperature resistance and good bending strength, is a low-cost long-life heat-absorbing ceramic, and the preparation process is simple.

[0095] The specific embodiments of the present application described above do not constitute a limitation on the scope of protection of the present application. Any various other corresponding changes and modifications made in accordance with the technical concept of the present application shall be included in the scope of protection of the claims of the present application.

Claims

1. A multi-oxide composite corundum-based heat-absorbing ceramic, characterized in that, By weight, it includes the following raw materials: 80-95 parts bauxite, 8-10 parts iron oxide, 0.4-1 parts titanium oxide, 6-8 parts copper oxide, and 1-5 parts additives; The additive includes cobalt oxide; The bauxite comprises: SiO2: 10-11%; Al2O3: 80-81%; CaO: 0.1-1%; Fe2O3: 1-2%; TiO2: 3-4%; MgO: 0.1-1%; K2O: 0.1-1%; Na2O: 0.01-0.1%; and a loss on ignition of 1-2%. The main crystalline phase of the multi-oxide composite corundum-based endothermic ceramic includes the corundum phase, and the secondary crystalline phases include iron titanate, copper cobalt spinel phase, and quartz phase.

2. The preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic as described in claim 1, characterized in that, Includes the following steps: S1, mix bauxite, iron oxide, titanium oxide, copper oxide and additives in proportion to obtain a mixed powder; S2, add an organic binder to the mixed powder for granulation, and after aging, press it into shape to obtain a green body; S3, after drying the green body, it is fired to obtain the multi-oxide composite corundum-based heat-absorbing ceramic.

3. The preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic according to claim 2, characterized in that, In step S1, bauxite, iron oxide, titanium oxide, copper oxide, and additives are ball-milled and mixed evenly.

4. The preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic according to claim 2, characterized in that, In step S2, the amount of organic binder added is 5-9% of the mass of the mixed powder; the organic binder is a polyvinyl alcohol aqueous solution with a mass concentration of 4-6%.

5. The preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic according to claim 2, characterized in that, In step S3, the aging conditions include aging at 25–30°C for 24–48 hours; The pressure for compression molding is 30-50 kN.

6. The preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic according to claim 2, characterized in that, In step S4, drying is carried out at 80–90°C for 24–48 hours.

7. The preparation method of the multi-oxide composite corundum-based heat-absorbing ceramic according to claim 2, characterized in that, In step S4, the firing conditions include: heating to 1320℃~1400℃ and holding at that temperature for 1~2 hours; The firing heating rate is 3-5℃ / min.

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