Preparation method of doped metal oxide ingot

Abstract

The invention relates to the field of optical coating material preparation, and discloses a preparation method of a doped metal oxide ingot. Mixing indium oxide powder, tantalum oxide powder and cerium oxide powder to obtain a mixture I; mixing the mixture I with an additive A, and performing primary granulation to obtain granulation powder I; the first mixture is pre-sintered, and clinker is obtained; pre-sintering the granulation powder I to obtain skeleton supporting particles; the pre-sintering temperature ranges from 1200 DEG C to 1350 DEG C; mixing the skeleton supporting particles, the clinker and an additive B, and performing secondary granulation; and sequentially carrying out compression molding and molding sintering on the granulation powder II to obtain the doped metal oxide ingot. The large-size and stable-size doped metal oxide ingot can be prepared, the forming density distribution is uniform, and cracking is avoided after sintering.

Description

Technical Field

[0001] The invention relates to the field of preparation of optical coating materials, and in particular to a method for preparing a doped metal oxide ingot. Background Art

[0002] In the field of optical coating, the demand for metal oxides is increasing year by year. They play a vital role in the field of high-performance optical thin film materials such as reflection, transmission, and anti-reflection of visible light, infrared light, and ultraviolet light. At the same time, doped metal oxide ingots, such as ITO, ICO, IGZO, etc., show their differences in different application fields due to their unique optical properties.

[0003] Currently, the size of doped metal oxide ingots is mainly concentrated in the range of 4 to 10 mm in height and 10 to 15 mm in diameter. However, large-sized doped metal oxide ingots with a diameter of more than 25 mm and a height of more than 40 mm are prone to uneven size and density distribution due to instability in the production process, which in turn causes cracking of the ingots after sintering, making it difficult to achieve stable and large-scale production. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a doped metal oxide ingot to solve at least one technical problem existing in the background technology.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: A method for preparing a doped metal oxide ingot comprises the following steps: (1) Indium oxide powder, tantalum oxide powder and cerium oxide powder are mixed in a mass ratio of 85-99:0.5-15:0.5-15 to obtain a mixture 1; (2) Mixing the mixed material 1 with the additive A and then granulating the mixed material 1 for the first time to obtain granulated powder 1; (3) pre-sintering the mixed material obtained in step (1) to obtain clinker; pre-sintering the granulated powder obtained in step (2) to obtain skeleton support particles; the pre-sintering temperature is 1200-1350°C; (4) mixing the skeleton support particles obtained in step (3), the clinker and the additive B, and granulating the mixture for the second time to obtain granulated powder II; (5) The granulated powder 2 is pressed and sintered in sequence to obtain a doped metal oxide ingot.

[0006] The present invention creatively achieves the coordinated optimization of material properties through doping metals and preparation processes, limits the types and components of doped metals, and pre-sinters to allow initial bonding between particles to form a stable and uniform skeleton structure, providing support for subsequent molding and sintering. The clinker obtained after sintering is used as a filling material and is granulated for a second time together with the skeleton support particles to further improve the performance of the material. Finally, the granulated powder is pressed into a green body of the desired shape in a mold; molding and sintering are performed to allow complete bonding between particles in the green body to form a dense and stable doped metal oxide ingot.

[0007] Furthermore, in step (1), the D50 of the indium oxide powder, tantalum oxide powder and cerium oxide powder is 1-5 μm. Furthermore, the purity of indium oxide powder is ≥4N; the purity of tantalum oxide powder is ≥3N; and the purity of cerium oxide powder is ≥3N.

[0008] Furthermore, in step (1), indium oxide powder, tantalum oxide powder and cerium oxide powder are added into a three-dimensional mixer in proportion and mixed for 10 to 20 hours to obtain a mixture 1.

[0009] Furthermore, in step (2), the additive A is at least one of PEG9000 and PEG6000.

[0010] It is further preferred that the additive A is added in an amount of 3-5% of the mass of the mixture.

[0011] Furthermore, step (2) is specifically as follows: taking mixed material 1 and putting it into a rotary granulator, modulating the chopper speed to 1000-1100 r / min, adjusting the nozzle rate of additive A to 10 mL / min, after spraying, rotating and granulating in the rotary granulator for 1-5 minutes, and after granulation is completed, taking out the granulated powder and drying it to obtain granulated powder 1.

[0012] More preferably, once the granulated powder is taken out, it is placed in a drying oven at 80-120° C. for drying, and when the volatile matter is fully volatilized and the weight loss rate of the granulated powder no longer decreases significantly, the granulated powder can be taken out and sieved.

[0013] Furthermore, in step (3), the granulated powder with a particle size greater than 40 mesh is screened for pre-sintering. In the present invention, the particle size is screened after the first granulation process to ensure the uniformity of the particle size.

[0014] It is further preferred that in step (2), the particle size of the particles obtained by the first granulation is 20-40 mesh.

[0015] Furthermore, during the pre-sintering process in step (3), an alumina crucible is used as a pre-sintering container.

[0016] Furthermore, in step (3), the mixed material is pre-sintered, and the obtained material is sieved through a 60-mesh sieve and then ball-milled for 10 to 20 hours to obtain a clinker.

[0017] Furthermore, in step (4), the mass ratio of the skeleton supporting particles to the clinker is 1~5:9~5.

[0018] Furthermore, in step (4), the additive B is at least one of PVA, liquid paraffin and water.

[0019] It is further preferred that the additive B is added in an amount of 1-3% of the total mass of the skeleton supporting particles and the clinker.

[0020] Furthermore, in step (4), the skeleton support particles, the clinker and the additive B are placed in a three-dimensional mixer and mixed for 10 to 20 hours, and then granulated for the second time.

[0021] Furthermore, in step (4), the granulation pressure of the second granulation is 3-15 MPa, and the pressure holding time is 3-15 s.

[0022] Furthermore, in step (5), the granulated powder with a particle size greater than 35 mesh is screened for compression molding; the screening ensures the uniformity of the particle size and further meets the molding requirements.

[0023] It is further preferred that in step (4), the particle size of the particles obtained by the second granulation is 40-60 mesh.

[0024] Furthermore, the step (5) of compression molding is specifically as follows: weighing the granulation powder 2 and adding it into a mold, using a double-sided pressure molding machine to flatten the upper and lower pressure heads of the mold and then demoulding.

[0025] Further preferably, the mass of the doped metal oxide ingot is calculated according to the theoretical density and size, and then the granulated powder 2 is weighed and added into the mold.

[0026] Furthermore, the molding and sintering temperature in step (5) is 1100-1250° C., and the molding and sintering time is 1-5 hours.

[0027] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes the sintering characteristics of raw materials to perform a pre-sintering process without introducing impurities, thereby greatly reducing the risk of shrinkage of the pellets after molding; a new granulation process is introduced into the preparation of skeleton support particles, and the granulation powder is pre-sintered to give it a higher particle strength, thereby avoiding the phenomenon of cracking and crushing due to insufficient particle strength during the pressing and molding process, which cannot play a supporting role; at the same time, the skeleton support particles are mixed with the powder, and the two support and fill each other, so that the overall strength distribution of the pellets can be uniform, and stable large-sized doped oxide ingots can be prepared.

[0028] The present invention creatively arranges skeleton supporting particles, and does not introduce new impurities when preparing the particles, thereby maintaining the original purity and greatly improving the stability of the finished product, thereby preparing large-sized doped metal oxide ingot products that are dimensionally stable and do not crack after firing.

[0029] The present invention mixes the skeleton support particles and the clinker fully and evenly and adds additives, and the obtained mixture is placed in the mold cavity of a molding mold for compression molding, so that the skeleton particles support each other and the clinker is fully filled between the particles, thereby controlling the upper, middle and lower molding strength and density uniform distribution of the entire product, and after molding and sintering, there will be no cracking of the ingots, deformity caused by uneven shrinkage and splashing during the application process caused by uneven density. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0031] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0033] Example 1 (1) Weigh 1600 g of indium oxide powder with a D50 of 0.32 μm and a purity of 4N, 100 g of tantalum oxide powder with a D50 of 1.63 μm and a purity of 4N, and 300 g of cerium oxide powder with a D50 of 0.84 μm and a purity of 4N, and add them into a 20 L three-dimensional mixer. Set the mixing frequency to 15 Hz and the mixing time to 10 h. Take out the uniformly mixed powder to obtain a mixture 1.

[0034] (2) Take 800 g of mixed material 1 and add it to the granulator. Add 32 mL of PEG9000 into the nozzle measuring cylinder, start the granulator, set the chopper speed to 1000 r / min, and the nozzle rate to 10 mL / min. After PEG9000 is completely sprayed in, let the granulator run for another 120 s to make the powder more uniformly granulated to obtain granulated powder 1.

[0035] (3) Place the granulated powder 1 in a drying oven, set the drying temperature to 95°C, and the drying time to 4.5 hours. After cooling, sieve the granulated powder 1 with a 40-mesh sieve to remove the powder that has not formed particles.

[0036] (4) 1200 g of mixed material 1 is placed in a group of alumina crucibles, and the screened granulated powder 1 is placed in another group of alumina crucibles, and are put into a tubular heated bell furnace for pre-sintering. The pre-sintering temperature is set to 1250°C, the heating rate is 5°C / min, the insulation time is 4h, and the cooling rate is 4°C / min. After the furnace body is cooled, the screened granulated powder 1 is pre-sintered to obtain strong skeleton support particles, and the mixed material 1 is pre-sintered to obtain clinker 1, whose sintering activity is greatly reduced.

[0037] (5) Place clinker 1 in a ball mill and mix zirconium oxide balls at a material-ball ratio of 1:1.8 for ball milling at a ball milling frequency of 28.8 Hz for 12 h. After the ball milling is completed, separate the zirconium oxide balls and powder to obtain clinker 2.

[0038] (6) Weigh 1000 g of clinker 2 and 500 g of skeleton support particles, add 15 mL of PVA, and stir while adding. After the addition is completed, pour it into the three-dimensional mixer for mixing. Set the mixing frequency to 15 Hz and the mixing time to 10 h. Take out the mixed material to obtain mixed material 2.

[0039] (7) Weigh 50 g / portion of Mixture 2, and press each portion into granules separately. Pour one portion of Mixture 2 into the die cavity of the pressure granulator, set the pressure to 20 MPa, and press for 10 s. Repeat the process until all Mixture 2 is pressed into granules. Crush and sieve the pressed Mixture 2, and sieve it with a 35-mesh sieve to ensure that all powder can pass through the 35-mesh sieve. The powder under the sieve is granulation powder 2.

[0040] (8) According to the size requirement of D30*45mm, select the molding mold and assemble it. According to the density of the sample pellet 4.2g·cm -3 According to the requirements, weigh 133.53g of granulation powder 2 and add it into the mold cavity of the forming mold. Place the upper pressure head and tighten the mold, place it flat in the double-sided hydraulic press, press the upper and lower pressure heads flat on its side baffles, ensure that the internal space height of the mold is 40mm, set the pressure to 15MPa, and hold the pressure for 5s. After the pressure holding is completed, take out the mold for demoulding operation and take out the ingot blank.

[0041] (9) Place the ingots and pellets on the firing plate of the tubular heating bell furnace, arrange them neatly, set the sintering temperature to 1150°C, the heating rate to 3°C / min, the holding time to 4h, and the cooling rate to 5°C / min. After the cooling is completed, take out the sintered ingots and pellets, inspect them and package them after they are qualified, and the large-sized doped metal oxide ingots and pellets are obtained.

[0042] Example 2 (1) Weigh 1700 g of indium oxide powder with a D50 of 0.32 μm and a purity of 4N, 50 g of tantalum oxide powder with a D50 of 1.63 μm and a purity of 4N, and 250 g of cerium oxide powder with a D50 of 0.84 μm and a purity of 4N into a 20 L three-dimensional mixer, set the mixing frequency to 15 Hz, and the mixing time to 10 h. Take out the uniformly mixed powder to obtain a mixture 1.

[0043] (2) Take 1000 g of mixed material 1 and add it to the granulator. Add 45 mL of PEG6000 into the nozzle measuring cylinder, start the granulator, set the chopper speed to 1020 r / min, and the nozzle rate to 10 mL / min. After PEG6000 is completely sprayed in, let the granulator run for another 145 s to make the powder more uniformly granulated to obtain granulated powder 1.

[0044] (3) Place the granulated powder 1 in a drying oven, set the drying temperature to 95°C, and the drying time to 4.5 hours. After cooling, sieve the granulated powder 1 with a 40-mesh sieve to remove the powder that has not formed particles.

[0045] (4) 1000 g of mixed material 1 is placed in a group of alumina crucibles, and the screened granulated powder 1 is placed in another group of alumina crucibles, and are put into a tubular heated bell furnace for pre-sintering. The pre-sintering temperature is set to 1350°C, the heating rate is 5°C / min, the insulation time is 4h, and the cooling rate is 4°C / min. After the furnace body is cooled, the screened granulated powder 1 is pre-sintered to obtain strong skeleton support particles, and the mixed material 1 is pre-sintered to obtain clinker 1, whose sintering activity is greatly reduced.

[0046] (5) Place clinker 1 in a ball mill and mix zirconium oxide balls at a material-ball ratio of 1:1.8 for ball milling at a ball milling frequency of 28.8 Hz for 12 h. After the ball milling is completed, separate the zirconium oxide balls and powder to obtain clinker 2.

[0047] (6) Weigh 900 g of clinker 2 and 400 g of skeleton support particles, add 12 mL of PVA, and stir while adding. After the addition is completed, pour it into the three-dimensional mixer for mixing. Set the mixing frequency to 15 Hz and the mixing time to 10 h. Take out the mixed material to obtain mixed material 2.

[0048] (7) Weigh 50 g / portion of Mixture 2, and press each portion into granules separately. Pour one portion of Mixture 2 into the die cavity of the pressure granulator, set the pressure to 20 MPa, and press for 10 s. Repeat the process until all Mixture 2 is pressed into granules. Crush and sieve the pressed Mixture 2, and sieve it with a 35-mesh sieve to ensure that all powder can pass through the 35-mesh sieve. The powder under the sieve is granulation powder 2.

[0049] (8) According to the size requirement of D35*60mm, the molding mold is selected and assembled. According to the density of the sample pellets 3.6g·cm -3 According to the requirements, weigh 207.7g of granulation powder 2 and add it into the mold cavity of the forming mold. Place the upper pressure head and tighten the mold, place it flat in the double-sided hydraulic press, press the upper and lower pressure heads flat on its side baffles, ensure that the internal space height of the mold is 60mm, set the pressure to 10MPa, and hold the pressure for 5s. After the pressure holding is completed, take out the mold for demoulding operation and take out the ingot blank.

[0050] (9) Place the ingots and pellets on the firing plate of the tubular heating bell furnace, arrange them neatly, set the sintering temperature to 1175°C, the heating rate to 3°C / min, the holding time to 4.2h, and the cooling rate to 5°C / min. After the cooling is completed, take out the sintered ingots and pellets, and package them after they are tested and qualified. The large-sized doped metal oxide ingots and pellets are obtained.

[0051] Example 3 (1) Weigh 1700 g of indium oxide powder with a D50 of 0.32 μm and a purity of 4N, 50 g of tantalum oxide powder with a D50 of 1.63 μm and a purity of 4N, and 250 g of cerium oxide powder with a D50 of 0.84 μm and a purity of 4N into a 20 L three-dimensional mixer, set the mixing frequency to 15 Hz, and the mixing time to 10 h. Take out the uniformly mixed powder to obtain a mixture 1.

[0052] (2) Take 1000 g of mixed material 1 and add it to the granulator. Add 45 mL of PEG6000 into the nozzle measuring cylinder, start the granulator, set the chopper speed to 1020 r / min, and the nozzle rate to 10 mL / min. After PEG6000 is completely sprayed in, let the granulator run for another 145 s to make the powder more uniformly granulated to obtain granulated powder 1.

[0053] (3) Place the granulated powder 1 in a drying oven, set the drying temperature to 95°C, and the drying time to 4.5 hours. After cooling, sieve the granulated powder 1 with a 40-mesh sieve to remove the powder that has not formed particles.

[0054] (4) 1000 g of mixed material 1 is placed in a group of alumina crucibles, and the screened granulated powder 1 is placed in another group of alumina crucibles, and are put into a tubular heated bell furnace for pre-sintering. The pre-sintering temperature is set to 1200°C, the heating rate is 5°C / min, the insulation time is 4h, and the cooling rate is 4°C / min. After the furnace body is cooled, the screened granulated powder 1 is pre-sintered to obtain strong skeleton support particles, and the mixed material 1 is pre-sintered to obtain clinker 1, whose sintering activity is greatly reduced.

[0055] (5) Place clinker 1 in a ball mill and mix zirconium oxide balls at a material-ball ratio of 1:1.8 for ball milling at a ball milling frequency of 28.8 Hz for 12 h. After the ball milling is completed, separate the zirconium oxide balls and powder to obtain clinker 2.

[0056] (6) Weigh 900 g of clinker 2 and 400 g of skeleton support particles, add 12 mL of PVA binder, and stir while adding. After the addition is completed, pour it into the three-dimensional mixer for mixing. Set the mixing frequency to 15 Hz and the mixing time to 10 h. Take out the mixed material to obtain mixed material 2.

[0057] (7) Weigh 50 g / portion of Mixture 2, and press each portion into granules separately. Pour one portion of Mixture 2 into the die cavity of the pressure granulator, set the pressure to 20 MPa, and press for 10 s. Repeat the process until all Mixture 2 is pressed into granules. Crush and sieve the pressed Mixture 2, and sieve it with a 35-mesh sieve to ensure that all powder can pass through the 35-mesh sieve. The powder under the sieve is granulation powder 2.

[0058] (8) According to the size requirement of D35*60mm, the molding mold is selected and assembled. According to the density of the sample pellets 3.6g·cm -3 According to the requirements, weigh 207.7g of granulation powder 2 and add it into the mold cavity of the forming mold. Place the upper pressure head and tighten the mold, place it flat in the double-sided hydraulic press, press the upper and lower pressure heads flat on its side baffles, ensure that the internal space height of the mold is 60mm, set the pressure to 10MPa, and hold the pressure for 5s. After the pressure holding is completed, take out the mold for demoulding operation and take out the ingot blank.

[0059] (9) Place the ingots and pellets on the firing plate of the tubular heating bell furnace, arrange them neatly, set the sintering temperature to 1175°C, the heating rate to 3°C / min, the holding time to 4.2h, and the cooling rate to 5°C / min. After the cooling is completed, take out the sintered ingots and pellets, and package them after they are tested and qualified. The large-sized doped metal oxide ingots and pellets are obtained.

[0060] Comparative Example 1 This comparative example is basically the same as Example 2, except that the pre-sintering temperature in step (4) is 1100°C.

[0061] Comparative Example 2 This comparative example is basically the same as Example 2, except that the pre-sintering temperature in step (4) is 1400°C.

[0062] Comparative Example 3 This comparative example is basically the same as Example 2, except that the molding sintering temperature in step (9) is 1000°C.

[0063] Comparative Example 4 This comparative example is basically the same as Example 2, except that the molding sintering temperature in step (9) is 1300°C.

[0064] Comparative Example 5 This comparative example is basically the same as Example 1, except that the mass ratio of the indium oxide powder, tantalum oxide powder and cerium oxide powder mixed in step (1) is different.

[0065] Specifically: weigh 1700g of indium oxide powder with a D50 of 0.32μm and a purity of 4N, 5g of tantalum oxide powder with a D50 of 1.63μm and a purity of 4N, and 295g of cerium oxide powder with a D50 of 0.84μm and a purity of 4N and add them into a 20L three-dimensional mixer.

[0066] Comparative Example 6 This comparative example is basically the same as Example 1, except that the mass ratio of the indium oxide powder, tantalum oxide powder and cerium oxide powder mixed in step (1) is different.

[0067] Specifically: weigh 1700g of indium oxide powder with a D50 of 0.32μm and a purity of 4N, 295g of tantalum oxide powder with a D50 of 1.63μm and a purity of 4N, and 5g of cerium oxide powder with a D50 of 0.84μm and a purity of 4N and add them into a 20L three-dimensional mixer.

[0068] Comparative Example 7 This comparative example is basically the same as Example 1, except for step (6).

[0069] Specifically: (6) Weigh 950 g of clinker 2 and 50 g of skeleton support particles, add 12 mL of PVA binder, and stir while adding. After the addition is completed, pour it into the three-dimensional mixer for mixing. Set the mixing frequency to 15 Hz and the mixing time to 10 h. Take out the mixed material to obtain mixed material 2.

[0070] Comparative Example 8 This comparative example is basically the same as Example 1, except for step (6).

[0071] Specifically: (6) Weigh 450 g of clinker 2 and 550 g of skeleton support particles, add 12 mL of PVA binder, and stir while adding. After the addition is completed, pour it into the three-dimensional mixer for mixing. Set the mixing frequency to 15 Hz and the mixing time to 10 h. Take out the mixed material to obtain mixed material 2.

[0072] The post-sintering dimensions, appearance and application tests of the doped metal oxide ingots obtained in Examples 1 to 3 and Comparative Examples 1 to 8 were tested, and the results are shown in Table 1.

[0073] Table 1 It can be seen that: The preparation method of the present application can prepare large-sized and dimensionally stable doped metal oxide ingots, which have no cracking after sintering, have little splashing during application testing, and have high utilization rate.

[0074] The pre-sintering temperature of comparative example 1 is too low, and the skeleton particles are not sintered and formed, resulting in insufficient formability and basically no formation. The pre-sintering temperature of comparative example 2 is too high, the skeleton particles are severely vitrified, the strength is too high, and uneven heat dissipation during application easily causes splashing, resulting in poor application effect and low utilization rate.

[0075] The molding sintering temperature of comparative example 3 was too low, resulting in serious deformation of the pellets after sintering and no obvious strength, and no molding. The molding sintering temperature of comparative example 4 was too high, and the overall ceramicization of the pellets was serious and the strength was too high, resulting in excessive stress and cracking, and severe splashing during the application test.

[0076] In the formula of Comparative Example 5, the proportion of tantalum oxide is reduced, and the proportion of cerium oxide is increased, and excessive energy is absorbed during the coating process, resulting in excessive splashing. In the formula of Comparative Example 6, the proportion of tantalum oxide is increased, resulting in the mobility not meeting the product requirements, resulting in unqualified coating products.

[0077] In Comparative Example 7, the content of the skeleton supporting particles is low, which cannot support the original shape of the particles and cannot be formed. In Comparative Example 8, the content of the skeleton supporting particles is high, resulting in loose and porous pellets after forming, and cracking after sintering.

[0078] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention.

Claims

1. A method for preparing a doped metal oxide ingot, characterized in that: The following steps are involved: (1) Indium oxide powder, tantalum oxide powder and cerium oxide powder are mixed in a mass ratio of 85-99:0.5-15:0.5-15 to obtain a mixture 1; (2) Mixing the mixed material 1 with the additive A and then granulating the mixed material 1 for the first time to obtain granulated powder 1; (3) pre-sintering the mixed material obtained in step (1) to obtain clinker; pre-sintering the granulated powder obtained in step (2) to obtain skeleton support particles; the pre-sintering temperature is 1200-1350°C; (4) mixing the skeleton support particles obtained in step (3), the clinker and the additive B, and granulating the mixture for the second time to obtain granulated powder II; (5) The granulated powder 2 is pressed and sintered in sequence to obtain a doped metal oxide ingot.

2. The preparation method according to claim 1, characterized in that In step (1), the D50 of the indium oxide powder, the tantalum oxide powder, and the cerium oxide powder is 1-5 μm; . The purity of indium oxide powder is ≥4N; the purity of tantalum oxide powder is ≥3N; the purity of cerium oxide powder is ≥3N.

3. The preparation method according to claim 1 or 2, characterized in that: In step (2), the additive A is at least one of PEG9000 and PEG6000; The amount of additive A added is 3-5% of the mass of the mixture.

4. The preparation method according to claim 1, characterized in that: In step (3), granulated powder with a particle size greater than 40 mesh is screened for pre-sintering; Preferably, the particle size of the particles obtained by the first granulation in step (2) is 20-40 mesh.

5. The preparation method according to claim 1, characterized in that: In step (3), the pre-sintering time is 3 to 10 hours.

6. The preparation method according to claim 1, characterized in that: In step (3), after the mixed material is pre-sintered, the obtained material is passed through a 60-mesh sieve and then ball-milled for 10 to 20 hours to obtain a clinker.

7. The preparation method according to claim 1, characterized in that: In step (4), the mass ratio of the skeleton supporting particles to the clinker is 1~5:9~5.

8. The preparation method according to claim 1 or 7, characterized in that: In step (4), the additive B is at least one of PVA, liquid paraffin, and water; The amount of the additive B added is 1-3% of the total mass of the skeleton supporting particles and the clinker.

9. The preparation method according to claim 1, characterized in that: In step (5), granulating powder 2 with a particle size greater than 35 mesh is screened and pressed into shape; Preferably, the particle size of the particles obtained by the second granulation in step (4) is 40-60 mesh.

10. The preparation method according to claim 1, characterized in that: The temperature of the molding and sintering in step (5) is 1100-1250°C; and the sintering time is 1-5 hours.

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