A core-shell structured ceramic powder and its preparation method and system

Abstract

A core-shell structured ceramic powder and its preparation method and system are disclosed. The preparation method involves forming a suspension system containing SiO2 cores under stirring and heating conditions. A pH adjuster is added dropwise to the reaction chamber to guide the reaction products of the ytterbium source solution and silicon source solution to deposit and grow on the surface of the SiO2 cores, forming a core-shell structured precursor. The precursor is then processed to obtain a core-shell structured ceramic powder comprising SiO2@Yb2Si2O7. The core material of this ceramic powder is SiO2, and the shell material is Yb2Si2O7. By using the SiO2 core as an internal silicon source library, in-situ self-compensation is achieved under high-temperature conditions, ensuring the stability of Yb2Si2O7. This prevents irreversible deoxidation decomposition of the Yb2Si2O7 phase during long-term operation in extreme environments with high temperature, high pressure, and high water-oxygen partial pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal protection, in particular to a core-shell structure ceramic powder and a preparation method and system thereof. BACKGROUND

[0002] Ytterbium disilicate (Yb2Si2O7) is a key candidate material for environmental barrier coatings (EBC) of the next generation of aero-engine and gas turbine hot end components, and its core advantages are excellent high-temperature stability, water-oxygen corrosion resistance and good chemical compatibility with silicon-based ceramics.

[0003] However, when Yb2Si2O7 is long-term served in an extreme environment of high temperature, high pressure and high water-oxygen partial pressure, irreversible deoxidation and decomposition of Yb2Si2O7 occurs, ytterbium monosilicate (Yb2SiO5) with mismatched thermal expansion coefficient (CTE) and significantly deteriorated protective performance is generated, resulting in phase transition stress of the environmental barrier coating, cracks and eventually accelerated peeling failure.

[0004] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The present application aims to overcome the problem of irreversible deoxidation and decomposition of Yb2Si2O7 when it is long-term served in an extreme environment of high temperature, high pressure and high water-oxygen partial pressure, and to provide a core-shell structure ceramic powder and a preparation method and system thereof.

[0006] According to one aspect of the present application, a preparation method of a core-shell structure ceramic powder is provided, which is realized by the above-mentioned preparation system of the core-shell structure ceramic powder, and the method comprises:

[0007] Injecting the suspension into the reaction cavity to form a suspension system containing SiO2 core under stirring and heating conditions;

[0008] Introducing ytterbium source solution and supplementary silicon source solution into the suspension system containing SiO2, and adding an acid-base adjusting agent into the reaction cavity to guide the reaction product of the ytterbium source solution and the silicon source solution to deposit and grow on the surface of the SiO2 core, thereby forming a core-shell structure precursor;

[0009] Processing the core-shell structure precursor to obtain a core-shell structure ceramic powder comprising SiO2@Yb2Si2O7.

[0010] In one embodiment of the present invention, the method is implemented using a preparation system for core-shell structured ceramic powder. This preparation system includes a raw material conveying module, a synthesis reaction module, and a processing module. The raw material conveying module includes a first silicon source storage tank, a second silicon source storage tank, a ytterbium salt storage tank, and a pH adjuster storage tank. The synthesis reaction module includes a reactor with a reaction chamber. A silicon source microchannel and a ytterbium source microchannel are provided at the top of the reactor and communicate with the reaction chamber. The silicon source microchannel is connected to the first and second silicon source storage tanks via pipelines, respectively. The ytterbium source microchannel is connected to the ytterbium salt storage tank via a pipeline. A first pump is provided between the reactor and the ytterbium salt storage tank. A connection is established between the reactor and the first and second silicon source storage tanks. A second pump body is installed on the pipeline, and a stirring motor is installed at the top of the reactor. The stirring shaft of the stirring motor extends into the reaction chamber. A separation umbrella and a stirring mechanism are sequentially installed on the stirring shaft in the direction away from the top of the reactor. The reaction chamber is connected to the pH regulator storage tank through a pipeline. A third pump body is installed on the pipeline between the reactor and the pH regulator injection pump. A pH sensor is installed on the reactor and extends into the reaction chamber. The pH sensor is electrically connected to the third pump body to form a closed-loop control circuit. A first heat exchanger is installed in the reaction chamber. A heater is installed on the side of the first heat exchanger away from the reaction chamber. The processing module is connected to the product outlet of the reaction chamber. The processing module is used to process the reactants output from the product outlet into powder.

[0011] In one embodiment of the present invention, the processing module includes a solid-liquid-gas separation unit, a solid-liquid separation unit, a water washing unit, an alcohol washing unit, a drying unit, a calcination unit, and a ball milling unit connected in sequence by pipelines. The preparation system also includes a recovery module, a pure water storage tank, an ethanol storage tank, and a waste liquid storage tank. The recovery module includes a second heat exchanger, a first membrane treatment unit, a second membrane treatment unit, and an evaporation unit. The second heat exchanger is connected to the first heat exchanger by pipelines. The first membrane treatment unit is connected to the alcohol washing unit by pipelines. The first membrane treatment unit is connected to the ethanol storage tank by pipelines. The solid-liquid separation unit is connected to the waste liquid storage tank by pipelines. The second membrane treatment unit is connected to the waste liquid storage tank by pipelines. The evaporation unit is connected to the second membrane treatment unit by pipelines. A first valve is provided on the pipeline between the ethanol storage tank and the second silicon source storage tank. A third valve and a fourth valve are provided on the pipeline between the pure water storage tank and the second silicon source storage tank.

[0012] In one embodiment of the present invention, injecting the suspension into a reaction vessel and forming a suspension system containing SiO2 cores under stirring and heating conditions includes:

[0013] The suspension of SiO2 nuclei stored in the first silicon source storage tank is injected into the reactor. The stirring shaft of the stirring motor is driven to rotate, and the stirring shaft drives the stirring mechanism to stir the suspension of SiO2 nuclei. At the same time, the heater is controlled to heat the suspension of SiO2 nuclei to form a suspension system containing SiO2 nuclei.

[0014] In one embodiment of the present invention, introducing a ytterbium source solution and a supplementary silicon source solution into a SiO2-containing suspension system includes:

[0015] The ytterbium source solution stored in the ytterbium salt storage tank is introduced into the suspension system containing SiO2 through the first pump body, and the silicon source solution stored in the second silicon source storage tank is added to the suspension system through the second pump body. The system is initially mixed through the silicon source microchannel and the ytterbium source microchannel, and then further mixed through the tangential flow of the separation umbrella.

[0016] In one embodiment of the present invention, the supplementary silicon source solution is an aqueous sodium silicate solution, the pH adjuster is ammonia, the reaction pH is 9-11, and the reaction temperature is 60-90°C; or the supplementary silicon source solution is an ethanol solution of tetraethyl orthosilicate, the pH adjuster is hydrochloric acid, and the reaction temperature is 70-85°C. The raw material conveying module also includes a pure water storage tank and an ethanol storage tank. A first valve is provided on the pipeline between the ethanol storage tank and the second silicon source storage tank, and a third valve and a fourth valve are provided on the pipeline between the pure water storage tank and the second silicon source storage tank. Before introducing the ytterbium source solution and the supplementary silicon source solution into the suspension system containing SiO2, the method further includes: when the first valve is closed, the third valve is opened, and the fourth valve is opened, an aqueous sodium silicate solution is formed in the second silicon source storage tank; or when the first valve is opened and the fourth valve is closed, an ethanol solution of tetraethyl orthosilicate is formed in the second silicon source storage tank.

[0017] In one embodiment of the present invention, the method further includes: when introducing the ytterbium source solution stored in the ytterbium salt storage tank and the silicon source solution stored in the second silicon source storage tank, adding a surface modifier to the ytterbium source solution and / or the silicon source solution, wherein the surface modifier is polyvinylpyrrolidone, polyvinyl alcohol or a silane coupling agent.

[0018] In one embodiment of the present invention, processing the core-shell structure precursor to obtain core-shell structure ceramic powder includes:

[0019] The core-shell structure precursor is subjected to solid-liquid separation, washing, drying, calcination at 1200-1500℃ for 1-5 hours and ball milling through the processing module to form core-shell structure ceramic powder including SiO2@Yb2Si2O7.

[0020] In one embodiment of the present invention, the method further includes: preparing a slurry by combining core-shell structured ceramic powder including SiO2@Yb2Si2O7 with a binder, and then performing spray granulation to obtain core-shell structured granulated powder including SiO2@Yb2Si2O7.

[0021] According to another aspect of the present invention, a core-shell structured ceramic powder is provided, which is prepared by the preparation method provided in another aspect of the present invention. The core-shell structured ceramic powder includes a core and a shell, wherein the material of the core is SiO2 and the material of the shell is Yb2Si2O7.

[0022] This invention drives the stirring shaft of a stirring motor to rotate, which in turn drives a stirring mechanism to stir the suspension of SiO2 cores. Simultaneously, a heater is controlled to heat the suspension of SiO2 cores, forming a suspension system containing SiO2 cores. Ytterbium source solution and silicon source solution are initially mixed via silicon source microchannels and ytterbium source microchannels, and then further mixed via tangential flow guidance through a separation umbrella. A closed-loop control circuit controls the dropping rate of a pH adjuster, guiding the reaction products of the ytterbium source solution and silicon source solution to deposit and grow on the surface of the SiO2 cores. This achieves uniform coating of the SiO2 core surface with a Yb2Si2O7 shell, forming a core-shell structure precursor. The core-shell structure precursor is then processed to obtain core-shell structured ceramic powder containing SiO2@Yb2Si2O7. The core of this core-shell structured ceramic powder is made of SiO2, and the shell is made of Yb2Si2O7. By using the SiO2 core as an internal silicon source library, the material achieves in-situ self-compensation under high temperature conditions, ensuring the stability of Yb2Si2O7. When operating in extreme environments with high temperature, high pressure, and high water and oxygen partial pressure for a long time, it can avoid the problem of irreversible deoxidation and decomposition of the Yb2Si2O7 phase.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0025] Figure 1 This is a schematic diagram of the preparation system for core-shell structured ceramic powder according to an embodiment of the present invention.

[0026] Figure 2 This is a front view of the internal structure of the reactor involved in an embodiment of the present invention.

[0027] Figure 3 This is a top view of the internal structure of the reactor involved in an embodiment of the present invention.

[0028] Figure 4 This is a flowchart illustrating the preparation method of core-shell structured ceramic powder according to an embodiment of the present invention.

[0029] Figure 5 This is a transmission electron microscope (TEM) image of the core-shell structured ceramic powder involved in an embodiment of the present invention.

[0030] Figure 6This is a scanning electron microscope image of the core-shell structured granulated powder involved in an embodiment of the present invention.

[0031] In the diagram: 1-Pure water machine; 2-Pure water storage tank; 3-Ethanol storage tank; 4-Ytterbium salt storage tank; 5-First silicon source storage tank; 6-Second silicon source storage tank; 7-pH adjuster storage tank; 8-Adhesive storage tank; 9-Surface modifier storage tank; 10-First pump body; 11-Second pump body; 12-Third pump body; 13-Fourth pump body; 14-Reaction vessel; 141-Vessel cover; 142-Vessel body; 143-Stirring motor; 144-Reaction chamber; 145-pH adjuster 146-Acidity / alkalinity regulator inlet; 147-Silicon source inlet; 148-Silicon source annular cavity; 149-Silicon source microchannel; 1410-Ytterbium source inlet; 1411-Ytterbium source annular cavity; 1412-Ytterbium source microchannel; 1413-Separation umbrella; 1414-Stirring frame; 1415-Stirring blades; 1416-Online acidity / alkalinity monitor; 1417-First heat exchanger; 1418-Heater; 1419-Heat exchange inlet; 142 0-Heat exchange outlet; 1421-Cooling water inlet; 1422-Cooling water outlet; 1423-Cooling coil; 1424-Product outlet; 1425-Uniform distribution plate; 15-Solid-liquid-gas separation unit; 16-Solid-liquid separation unit; 17-Water washing unit; 18-Alcohol washing unit; 19-Drying unit; 20-Calcination unit; 21-Ball milling unit; 22-Mother liquor tank; 23-Fifth pump body; 24-Heating steam tank; 25-Atomizing tower; 26-Heat exchange air 27-Second heat exchanger; 28-Dust collector bag; 29-Fan; 30-Condensation reflux unit; 31-Waste liquid storage tank; 32-First membrane treatment unit; 33-Second membrane treatment unit; 34-Evaporation unit; 35-Ethanol recovery unit; 36-By-product salt unit; 37-First flow meter; 38-Second flow meter; 39-First temperature instrument; 40-Second temperature instrument; 100-Core-shell structure ceramic powder; 200-Core-shell structure granulated powder. Detailed Implementation

[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted. Furthermore, the drawings are merely illustrative of the invention and are not necessarily drawn to scale.

[0033] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "upper" will become the component described as "lower." When a structure is "upper" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0034] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0035] Ytterbium bis(Si) silicate (Yb₂Si₂O₇) is a key candidate material for environmental barrier coatings (EBCs) of hot-end components in next-generation aero-engines and gas turbines. Its core advantages lie in its excellent high-temperature stability, resistance to water and oxygen corrosion, and good chemical compatibility with silicon-based ceramics. However, Yb₂Si₂O₇ faces challenges in long-term operation at high temperatures (…). In extreme environments (1300℃), high pressure, and high water and oxygen partial pressure), Yb2Si2O7 undergoes irreversible deoxidation and decomposition, generating ytterbium monosilicate (Yb2SiO5) with mismatched coefficient of thermal expansion (CTE) and significantly degraded protective performance. This leads to phase transformation stress in the environmental barrier coating, cracking, and ultimately accelerated peeling and failure.

[0036] Based on this, embodiments of the present invention provide a system for preparing core-shell structured ceramic powder. For example... Figures 1 to 3As shown, the preparation system for the core-shell structured ceramic powder includes a raw material conveying module, a synthesis reaction module, and a processing module. The raw material conveying module includes a first silicon source storage tank 5, a second silicon source storage tank 6, a ytterbium salt storage tank 4, and a pH adjuster storage tank 7. The synthesis reaction module includes a reactor 14, which has a reaction chamber 144. The top of the reactor 14 is provided with a silicon source microchannel 149 and a ytterbium source microchannel 1412 communicating with the reaction chamber 144. The silicon source microchannel 149 is connected to the first silicon source storage tank 5 and the second silicon source storage tank 6 through pipelines, respectively. The ytterbium source microchannel 1412 is connected to the ytterbium salt storage tank 4 through a pipeline. A first pump body 10 is provided between the reactor 14 and the ytterbium salt storage tank 4. A second pump body 11 is provided on the pipeline between the reactor 14 and the first silicon source storage tank 5 and the second silicon source storage tank 6. A stirring motor 143 is provided on the top of the reactor 14, and the stirring shaft of the stirring motor 143 extends into the reaction chamber 144 to stir. A separation umbrella 1413 and a stirring mechanism are sequentially arranged on the stirring shaft in the direction away from the top of the reactor 14. The reaction chamber 144 is connected to the pH regulator storage tank 7 through a pipeline. A third pump body 12 is provided on the pipeline between the reactor 14 and the pH regulator injection pump. A pH sensor is provided on the reactor 14 and extends into the reaction chamber 144. The pH sensor is electrically connected to the third pump body 12 to form a closed-loop control circuit. A first heat exchanger 1417 is provided in the reaction chamber 144. A heat exchange inlet 1419 is provided on the side of the first heat exchanger 1417 near the product outlet 1424. A heat exchange outlet 1420 is provided on the side of the first heat exchanger 1417 near the reactor cover 141. A heater 1418 is provided on the side of the first heat exchanger 1417 away from the reaction chamber 144. The processing module is connected to the product outlet 1424 of the reaction chamber 144. The processing module is used to process the reactants output from the product outlet 1424 into powder.

[0037] The suspension of SiO2 nuclei stored in the first silicon source storage tank 5 is injected into the reactor 14. The stirring shaft of the stirring motor 143 is driven to rotate, and the stirring shaft drives the stirring mechanism to stir the suspension of SiO2 nuclei. At the same time, the heater 1418 is controlled to heat the suspension of SiO2 nuclei to form a suspension system containing SiO2 nuclei. The ytterbium source solution stored in the ytterbium salt storage tank 4 is introduced into the suspension system containing SiO2 through the first pump body 10. The silicon source solution stored in the second silicon source storage tank 6 is added to the suspension system through the second pump body 11. The system is initially mixed through the silicon source microchannel 149 and the ytterbium source microchannel 1412, and then further mixed by tangential flow through the separation umbrella 1413. A closed-loop control circuit controls the third pump 12 to drop pH regulator stored in pH regulator tank 7 into reaction chamber 144, guiding the reaction products of ytterbium source solution and silicon source solution to deposit and grow on the surface of SiO2 core. This achieves uniform coating of Yb2Si2O7 shell on the SiO2 core surface, forming a core-shell structure precursor. Processing the precursor yields core-shell structured ceramic powder containing SiO2@Yb2Si2O7. The core material of this ceramic powder is SiO2, and the shell material is Yb2Si2O7. By using the SiO2 core as an internal silicon source library, in-situ self-compensation is achieved, ensuring the stability of Yb2Si2O7. This prevents irreversible deoxidation of the Yb2Si2O7 phase during long-term operation in extreme environments with high temperature, high pressure, and high water-oxygen partial pressure.

[0038] The preparation system for core-shell structured ceramic powder involved in the embodiments of the present invention will be described in detail below with reference to specific examples.

[0039] like Figures 1 to 3 As shown, the preparation system for core-shell structured ceramic powder includes a raw material conveying module and a synthesis reaction module. The synthesis reaction module includes a reactor 14, which comprises a reactor body 142, a reactor lid 141, and a stirring motor 143. The reactor lid 141 is located on top of the reactor body 142. The stirring motor 143 has a stirring shaft that passes through the reactor lid 141 and extends into the reaction chamber 144 of the reactor 14. The area of ​​the reactor lid 141 surrounding the stirring motor 143 is provided with a silicon source inlet 147 and... Ytterbium source inlet 1410, silicon source inlet 147 and ytterbium source inlet 141 are located at different radii of the same center of the vessel cover 141. Silicon source inlet 147 is connected to silicon source annular cavity 148 inside the vessel cover 141. Silicon source microchannel 149 is connected to silicon source annular cavity 148 and reaction chamber 144. Ytterbium source inlet 1410 is connected to ytterbium source annular cavity 1411 inside the vessel cover 141. Ytterbium source microchannel 1412 is connected to ytterbium source annular cavity 1411 and reaction chamber 144.

[0040] The stirring shaft of the stirring motor 143 extends into the reaction chamber 144. A separation umbrella 1413 and a stirring mechanism are sequentially arranged on the stirring shaft in the direction away from the vessel cover 141. The stirring mechanism includes a stirring frame 1414 and stirring blades 1415. The stirring blades 1415 are located at the end of the stirring shaft away from the vessel cover 141, and the stirring frame 1414 is located between the stirring blades 1415 and the separation umbrella 1413. A product outlet 1424 is provided at the end of the vessel body 142 away from the vessel cover 141.

[0041] The raw material conveying module includes a first silicon source storage tank 5, a second silicon source storage tank 6, a ytterbium salt storage tank 4, a pH adjuster storage tank 7, and a surface modifier storage tank 9. The first silicon source storage tank 5 and the second silicon source storage tank 6 are connected by pipelines, and the surface modifier storage tank 9 is connected to the ytterbium salt storage tank 4 and the second silicon source storage tank 6 by pipelines. The first silicon source storage tank 5 and the second silicon source storage tank 6 are connected to the silicon source microchannel 149 by pipelines, and the ytterbium salt storage tank 4 is connected to the ytterbium source microchannel 1412 by pipelines. A first pump body 10 is provided between the reaction vessel 14 and the ytterbium salt storage tank 4, and a second pump body 11 is provided on the pipeline between the reaction vessel 14 and the first silicon source storage tank 5 and the second silicon source storage tank 6.

[0042] A pH regulator storage tank 7 is connected to a pH regulator inlet 145 via a pipeline. The pH regulator inlet 145 is connected to a pH regulator flow channel 146 on the vessel cover 141. The pH regulator flow channel 146 is connected to the reaction chamber 144, and a uniform distribution plate 1425 is provided in the pH regulator flow channel 146. A third pump body 12 is provided on the pipeline between the reaction vessel 14 and the pH regulator storage tank 7. A pH sensor is provided on the reaction vessel 14, extending into the reaction chamber 144. The pH sensor is electrically connected to the third pump body 12, forming a closed-loop control circuit to achieve precise adaptive control of reaction conditions. A first heat exchanger 1417 is provided inside the reaction chamber 144, and a heater 1418 is provided on the side of the first heat exchanger 1417 away from the reaction chamber 144. The first heat exchanger 1417 and the heater 1418 work together to provide a precise temperature environment for the reaction.

[0043] The raw material conveying module also includes a pure water machine 1, a pure water storage tank 2 and an ethanol storage tank 3. The pure water machine 1 and the pure water storage tank 2 are connected by pipelines. The pure water storage tank 2 and the ethanol storage tank 3 are respectively connected to the second silicon source storage tank 6 by pipelines. A fourth pump body 13 is provided on the pipeline connected to the ethanol storage tank 3.

[0044] The preparation system for core-shell structured ceramic powder also includes a processing module and a powder processing module. The processing module includes a solid-liquid-gas separation unit 15, a solid-liquid separation unit 16, a water washing unit 17, an alcohol washing unit 18, a drying unit 19, a calcination unit 20, and a ball milling unit 21 connected in sequence by pipelines. The solid-liquid-gas separation unit 15 is connected to the product outlet 1424 by pipelines, and the alcohol washing unit 18 is connected to the ethanol storage tank 3 by pipelines. The powder processing module includes a mother liquor tank 22, a fifth pump body 23, a heating steam tank 24, an atomizing tower 25, a heat exchange cavity 26, a second heat exchanger 27, a dust collector bag 28, and a fan 29. The fifth pump body 23 is located on the pipeline between the mother liquor tank 22 and the atomizing tower 25. The second heat exchanger 27 is connected to the atomizing tower 25 through a pipeline. The heat exchange cavity 26 is equipped with a dust collector bag 28. The second heat exchanger 27 is connected to the fan 29 through a pipeline. The cavities of the second heat exchanger 27 located on both sides of the dust collector bag 28 are respectively connected to the heat exchange inlet 1419 and the heat exchange outlet 1420. The reactor body 142 is equipped with a cooling coil 1423 near the product outlet 1424. The two ends of the cooling coil 1423 are respectively connected to a cooling water inlet 1421 and a cooling water outlet 1422.

[0045] The preparation system for core-shell structured ceramic powder also includes a resource utilization module, which comprises a condensation reflux unit 30, a waste liquid storage tank 31, a first membrane treatment unit 32, a second membrane treatment unit 33, an evaporation unit 34, an ethanol recovery unit 35, and a byproduct salt unit 36. The condensation reflux unit 30 is connected via pipeline between the pH adjuster storage tank 7 and the solid-liquid-gas separation unit 15. The waste liquid storage tank 31 is connected via pipeline to the solid-liquid separation unit 16. The first membrane treatment unit 32 is connected to the alcohol washing unit 18 via pipeline, the second membrane treatment unit 33 is connected to the waste liquid storage tank 31 via pipeline, the evaporation unit 34 is connected to the second membrane treatment unit 33 via pipeline, the ethanol recovery unit 35 is connected to the second membrane treatment unit 33 via pipeline, and the byproduct salt unit 36 ​​is connected to the evaporation unit 34 via pipeline. The waste heat from the atomizing tower 25 is transferred to the first heat exchanger 1417 via the second heat exchanger 27, achieving energy cascade utilization. The waste ethanol from the alcohol washing unit 18 is purified by the first membrane treatment unit 32 and returned to the ethanol storage tank 3 for reuse. The outlet of the waste liquid storage tank 31 achieves water resource reuse and by-product salt recovery through the second membrane treatment unit 33 and the evaporation unit 34, thereby realizing the green manufacturing of core-shell structure ceramic powder.

[0046] The preparation system for core-shell structured ceramic powder also includes a first valve V1, a second valve V2, a third valve V3, a fourth valve V4, a fifth valve V5, a sixth valve V6, a seventh valve V7, an eighth valve V8, a ninth valve V9, a tenth valve V10, and an eleventh valve V11. The first valve V1 and the fourth valve V4 are located on the pipeline between the fourth pump body 13 and the first silicon source storage tank 5. The third valve V3 is located on the pipeline between the pure water storage tank 2 and the first silicon source storage tank 5. The second valve V2 is located on the pipeline between the ytterbium salt storage tank 4 and the pure water storage tank 2. The fifth valve V5 is located on the pipeline between the pH adjuster storage tank 7 and the pure water storage tank 2. The sixth valve V6 is located on the pipeline between the adhesive storage tank 8 and the pure water storage tank 2. The seventh valve V7 is located on the pipeline between the surface modifier storage tank 9 and the ytterbium salt storage tank 4. The eighth valve V8 is located on the pipeline between the surface modifier storage tank 9 and the second silicon source storage tank 6. The ninth valve V9 is located on the pipeline from the first silicon source storage tank 5. The tenth valve V10 is located on the pipeline from the second silicon source storage tank 6. The eleventh valve V11 is located on the pipeline from the reactor 14.

[0047] A first flow meter 37 is installed between the ytterbium salt storage tank 4 and the seventh valve V7; a second flow meter 38 is installed between the second silicon source storage tank and the eighth valve V8; a first temperature instrument 39 is connected to the first heat exchanger 1417; and a second temperature instrument 40 is installed on the pipeline between the heat exchange inlet 1419 and the second heat exchanger 27. It should be noted that the first heat exchanger 1417 and the second heat exchanger 27 are not limited to coil heat exchangers, shell-and-tube heat exchangers, plate heat exchangers, spiral plate heat exchangers, and heat pipe heat exchangers. The membrane separation technologies used in the first membrane treatment unit 32 and the second membrane treatment unit 33 are not limited to microfiltration, ultrafiltration, nanofiltration, reverse osmosis, electrodialysis, and membrane distillation technologies. The drying unit 19 is not limited to forced-air drying, vacuum drying, microwave drying, freeze drying, and fluidized bed drying. The ball milling unit 21 is not limited to planetary ball mills, vibratory ball mills, sand mills, air jet mills, and vortex mills.

[0048] This invention also provides a method for preparing core-shell structured ceramic powder. This is achieved using the core-shell structured ceramic powder preparation system mentioned above. For example... Figures 1 to 4 As shown, the method includes:

[0049] Step S10: The suspension is injected into the reaction chamber 144 to form a suspension system containing SiO2 cores under stirring and heating conditions;

[0050] Step S20: Ytterbium source solution and supplemented silicon source solution are introduced into the suspension system containing SiO2, and pH regulator is added dropwise to reaction chamber 144 to guide the reaction products of ytterbium source solution and silicon source solution to deposit and grow on the surface of SiO2 core to form core-shell structure precursor.

[0051] Step S30: Process the core-shell structure precursor to obtain core-shell structured ceramic powder including SiO2@Yb2Si2O7.

[0052] In step S10, when the first valve V1 is closed and the third valve V3 is open, spherical SiO2 nuclei with a particle size of 0.3-1μm are prepared into a suspension with a solid content of 1-10wt% in the first silicon source storage tank 5. When the ninth valve V9 is opened and the tenth valve V10 is closed, the suspension of SiO2 nuclei stored in the first silicon source storage tank 5 is injected into the reactor 14, and the stirring shaft of the stirring motor 143 is driven to rotate. The stirring shaft drives the stirring mechanism to stir the suspension of SiO2 nuclei. The stirring speed of the stirring shaft is 100-500rpm. At the same time, the heater 1418 is controlled to heat the suspension of SiO2 nuclei to 60-90℃ to form a suspension system containing SiO2 nuclei.

[0053] In step S20, the second valve V2 is opened, forming a ytterbium nitrate solution or ytterbium acetate solution with a concentration of 0.1-1.0 mol / L in the ytterbium salt storage tank 4. The ytterbium source solution with a concentration of 0.1-1.0 mol / L stored in the ytterbium salt storage tank 4 is introduced into the suspension system containing SiO2 through the first pump body 10 at a flow rate of 10-500 mL / min. The silicon source solution stored in the second silicon source storage tank 6 is added to the suspension system through the second pump body 11. The initial homogeneous mixing is achieved by microscale turbulence generated by the silicon source microchannel 149 and the ytterbium source microchannel 1412. Then, the macroscopic secondary mixing is completed by tangential flow through the separation umbrella 1413, ensuring that the reaction products of the ytterbium source solution and the silicon source solution reach molecular-level contact on the core surface of the SiO2 material.

[0054] The reaction system is monitored in real time by a pH sensor, and the feedback signal is used to control the third pump 12. A closed-loop control circuit controls the third pump 12 to slowly add pH regulator stored in the pH regulator tank 7 to the reaction chamber 144 at a rate of 0.1-5 mL / min. During this process, by precisely controlling the supersaturation of the reaction system, the reaction products are guided to selectively deposit and grow on the SiO2 core surface, effectively inhibiting homogeneous nucleation and forming a uniformly coated core-shell structure precursor. In step S20, 0.1-5 wt% of a surface modifier (such as polyvinylpyrrolidone, polyvinyl alcohol, or a silane coupling agent) can be added to further promote selective adsorption and coating by controlling the electrostatic interactions and steric hindrance between particles.

[0055] It should be noted that ytterbium salts are not limited to one or more salts that can provide ytterbium ions, such as ytterbium chloride, ytterbium nitrate, ytterbium acetate, and ytterbium sulfate; the silicon source in the first silicon source storage tank 5 is a silica suspension; the silicon source in the second silicon source storage tank 6 is not limited to one or more organic and inorganic substances such as sodium silicate, potassium silicate, and tetraethyl orthosilicate; the pH adjuster is not limited to one or more substances that can provide hydrogen ions and hydroxide ions, such as ammonia, citric acid, hydrochloric acid, nitric acid, and urea.

[0056] In step S20, when the preparation system uses a chemical co-precipitation method to prepare core-shell structured ceramic powder including SiO2@Yb2Si2O7, the supplementary silicon source solution is an aqueous sodium silicate solution, the pH adjuster is ammonia, the reaction pH is 9-11, the reaction temperature is 60-90℃, and the reaction is carried out in an aqueous phase system. When the first valve V1 is closed, the third valve V3 is open, and the fourth valve V4 is open, the second silicon source storage tank 6 can select an aqueous sodium silicate solution as the silicon source for the shell, and the silica suspension in the first silicon source storage tank 5 as the core material. When the ninth valve V9 is closed and the tenth valve V10 is open, the aqueous sodium silicate solution stored in the second silicon source storage tank 6 is injected into the reaction vessel 14 through the second pump body 11.

[0057] In step S20, when the preparation system uses the sol-gel method to prepare core-shell structured ceramic powder including SiO2@Yb2Si2O7, the supplementary silicon source solution is tetraethyl orthosilicate ethanol solution, the pH adjuster is hydrochloric acid or nitric acid, the reaction temperature is 70-85℃, and the reaction is carried out in an alcohol phase system. When the first valve V1 is open and the fourth valve V4 is closed, the tetraethyl orthosilicate ethanol solution in the second silicon source tank 6 serves as the silicon source for the shell, while maintaining the surface modifier's modification function on the reaction system. When the ninth valve V9 is closed and the tenth valve V10 is open, the tetraethyl orthosilicate ethanol solution stored in the second silicon source tank 6 is injected into the reaction vessel 14 through the second pump body 11.

[0058] Understandably, by switching the first valve V1 and the fourth valve V4, water or ethanol solvent can be introduced into the second silicon source tank 6, making the supplementary silicon source solution an aqueous solution of sodium silicate or an ethanol solution of tetraethyl orthosilicate. This allows for flexible configuration of the supplementary silicon source solution required for the second silicon source tank 6 or the sol-gel method, thereby achieving flexible switching of the reaction path. The seventh valve V7 and the eighth valve V8 can also be opened to add 0.5-2.0 wt% of a surface modifier to the ytterbium source solution or silicon source solution, achieving online surface modification of the ytterbium source solution and / or silicon source solution. It should be noted that the surface modifier is not limited to one or more nanoparticle modifying substances such as polyvinylpyrrolidone, polyvinyl alcohol, hexadecyltrimethylammonium bromide, or silane coupling agents.

[0059] In step S30, the core-shell precursor is sequentially passed through solid-liquid-gas separation unit 15 for solid-liquid-gas separation, solid-liquid separation unit 16 for solid-liquid separation, washed with deionized water in water washing unit 17, washed with ethanol in alcohol washing unit 18, and dried in drying unit 19. Subsequently, it is calcined in air at 1200-1500℃ for 1-5 hours to transform the amorphous core-shell precursor into a crystalline, structurally stable Yb₂Si₂O₇ core-shell precursor. Finally, it is ball-milled to obtain uniformly sized core-shell ceramic powder containing SiO₂@Yb₂Si₂O₇. Alcohol washing unit 18 is connected to ethanol storage tank 3 via pipeline to purify and recover the ethanol waste liquid generated during the washing process.

[0060] The method may further include step S40, in which core-shell structured ceramic powder comprising SiO2@Yb2Si2O7 is mixed with 1-5 wt% of a binder (such as polyethylene glycol or polyvinyl alcohol) to form a slurry with a solid content of 30-50%. This slurry is then spray-granulated through an atomizing tower 25 at an inlet temperature of 150-250℃ to obtain SiO2@Yb2Si2O7 core-shell structured granulated powder with good sphericity and a particle size distribution of 30-80 μm. This size of core-shell structured granulated powder can be directly used in spray coating processes. The second heat exchanger 27 is connected to the first heat exchanger 1417 via a pipeline, recovering the waste heat of 150-200℃ generated during the spray granulation process to the first heat exchanger 1417 to heat the synthesis reaction module, thereby achieving green manufacturing of the core-shell structured ceramic powder. It should be noted that the binder is not limited to polyvinyl alcohol, polyethylene glycol, cellulose ether, or one or more binders that can be completely burned off (leaving no ash).

[0061] When the preparation system uses a chemical co-precipitation method to prepare core-shell structured ceramic powder including SiO2@Yb2Si2O7, the preparation method of the core-shell structured ceramic powder is described in detail, and the preparation method includes:

[0062] In step S101, the first valve V1 is closed and the third valve V3 is opened. Spherical SiO2 cores with a particle size of 0.3-1 μm are prepared into a suspension with a solid content of 1-10 wt% in the first silicon source storage tank 5, serving as the silicon source solution. Then, the first valve V1 is closed, the third valve V3 is opened, and the fourth valve V4 is opened, forming a sodium silicate aqueous solution in the second silicon source storage tank 6 as a supplementary silicon source. The silica suspension in the first silicon source storage tank 5 can be selected as the core material, and the sodium silicate aqueous solution in the second silicon source storage tank 6 can be selected as the silicon source for the shell.

[0063] The ninth valve V9 is opened and the tenth valve V10 is closed, allowing the suspension of SiO2 nuclei stored in the first silicon source storage tank 5 to be injected into the reactor 14 via the second pump body 11. The stirring shaft of the driving stirring motor 143 rotates, and the stirring shaft drives the stirring mechanism to stir the suspension of SiO2 nuclei. The stirring speed of the stirring shaft is 100-500 rpm. At the same time, the heater 1418 is controlled to heat the suspension of SiO2 nuclei to 60-90℃ to form a suspension system containing SiO2 nuclei.

[0064] In step S201, the second valve V2 is opened, forming a ytterbium nitrate solution or ytterbium acetate solution with a concentration of 0.1-1.0 mol / L in the ytterbium salt storage tank 4, which serves as the ytterbium source solution. The ytterbium nitrate solution or ytterbium acetate solution stored in the ytterbium salt storage tank 4 is introduced into the suspension system containing SiO2 through the first pump body 10. When the ninth valve V9 is closed and the tenth valve V10 is opened, the sodium silicate aqueous solution stored in the second silicon source storage tank 6 is replenished into the suspension system through the second pump body 11. The sodium silicate solution undergoes initial distribution and micro-mixing through the silicon source microchannel 149 and the ytterbium source microchannel 1412, and then undergoes secondary mixing through the tangential flow guidance of the separation umbrella 1413. In conjunction with the shear flow field generated by the stirring mechanism, ultra-uniform dispersion of materials at the molecular scale is achieved.

[0065] When introducing the ytterbium source solution stored in the ytterbium salt storage tank 4 and the silicon source solution stored in the second silicon source storage tank 6, 0.5-2.0 wt% of surface modifier is added to the ytterbium nitrate solution or ytterbium acetate solution and sodium silicate aqueous solution by opening the seventh valve V7 and the eighth valve V8, so as to achieve online surface modification of the ytterbium source solution and / or silicon source solution. Polyvinylpyrrolidone solution can be selected in the surface modifier storage tank 9.

[0066] A closed-loop control circuit is activated, and intelligent temperature control is achieved through the synergistic action of heater 1418 and first heat exchanger 1417, raising the temperature of reaction chamber 144 to 60-90℃. Ammonia water in pH regulator storage tank 7 is slowly added to the reaction system via third pump 12. Through the interlocking feedback between pH online monitoring meter 1416 and third pump 12, the pH of the reaction system is precisely controlled within the range of 9-11. Under these reaction conditions, the reaction continues for 2-6 hours, causing ytterbium ions and silicate ions to co-precipitate on the core surface of silica. By precisely controlling the supersaturation of the reaction system, the reaction products are guided to preferentially deposit and grow on the SiO2 core surface, effectively inhibiting homogeneous nucleation and forming a core-shell structure precursor with uniformly coated silica / ytterbium hydroxide.

[0067] In step S301, the core-shell precursor is processed by the solid-liquid-gas separation unit 15. The volatilized ammonia gas is recovered by the condensation reflux unit 30 and returned to the pH adjuster storage tank 7 for recycling. The remaining slurry enters the solid-liquid separation unit 16 to achieve liquid-solid separation. The resulting solid product is purified by sequentially passing through the water washing unit 17 and the alcohol washing unit 18. The purified core-shell precursor is then processed by the drying unit 19, the calcination unit 20, and the ball milling unit 21 to obtain crystallized core-shell ceramic powder containing SiO2@Yb2Si2O7.

[0068] In step S401, the core-shell structure ceramic powder is mixed with the polyethylene glycol solution conveyed by the binder storage tank 8 in the mother liquor tank 22, and then conveyed to the atomization tower 25 by the fourth pump body 13. After centrifugal atomization, spray granulation is performed to finally obtain core-shell structure granulated powder with uniform particle size distribution including SiO2@Yb2Si2O7.

[0069] Throughout the reaction and granulation process, the resource utilization module enables the utilization of waste heat and the recovery of solvents. Waste ethanol generated in the alcohol washing unit 18 is purified by the first membrane treatment unit 32 and returned to the ethanol storage tank 3 for reuse. The second membrane treatment unit 33 and the evaporation unit 34 further process the ethanol, achieving water reuse and the recovery of the byproduct sodium salt. Waste heat generated in the atomizing tower 25 is transferred through the second heat exchanger 27 to the loop formed by the first heat exchanger 1417 to continuously heat the synthesis reaction, achieving a cascaded recycling of system energy. The heater 1418 automatically replenishes heat only during startup and when insufficient, ensuring a constant and controllable temperature.

[0070] When the preparation system uses the sol-gel method to prepare core-shell structured ceramic powder including SiO2@Yb2Si2O7, the preparation method of the core-shell structured ceramic powder is described in detail. The preparation method includes:

[0071] Step S102 is basically the same as step S101 in the above embodiment, and will not be described again here.

[0072] In step S202, the first valve V1 is opened and the fourth valve V4 is closed, forming an orthosilicate ethanol solution in the second silicon source storage tank 6. When the ninth valve V9 is closed and the tenth valve V10 is opened, the orthosilicate ethanol solution stored in the second silicon source storage tank 6 is replenished to the suspension system through the second pump body 11. The solution undergoes initial distribution and micro-mixing via the silicon source microchannel 149 and the ytterbium source microchannel 1412, followed by secondary mixing via the tangential flow guidance of the separation umbrella 1413. This, combined with the shear flow field generated by the stirring mechanism, achieves ultra-uniform dispersion of the material at the molecular scale. Step S202 also includes online surface modification of the ytterbium source solution and / or the silicon source solution. The online surface modification of the ytterbium source solution and / or the silicon source solution is the same as in step S201 and will not be described again here.

[0073] A closed-loop control circuit is activated, and the reaction system is maintained at a temperature range of 70-85°C through the heating action of the first heat exchanger 1417 and heater 1418. Subsequently, hydrochloric acid solution from the pH regulator storage tank 7 is slowly introduced into the reaction system through the third pump 12. The pH is precisely controlled through a feedback loop between the online pH monitor 1416 and the third pump 12. Under these conditions, the tetraethyl orthosilicate ethanol solution undergoes a controllable hydrolysis and condensation reaction, forming a three-dimensional network of ytterbium silicate gel, which uniformly coats the silica core surface, constructing a complete core-shell gel precursor.

[0074] Step S302 is basically the same as step S301 in the above embodiment, and will not be described again here.

[0075] like Figure 5 As shown, the present invention also provides a core-shell structured ceramic powder 100 prepared by steps S10-S30 of the above preparation method. The core-shell structured ceramic powder 100 includes a core and a shell, the material of the core is SiO2, and the material of the shell is Yb2Si2O7. Figure 5 This is a transmission electron microscope (TEM) image of core-shell ceramic powder containing SiO2@Yb2Si2O7. It can be seen that the silica core is coated with a continuous, dense, and relatively smooth Yb2Si2O7 shell, with a thickness of 100-300 nm. This shell is a well-crystallized continuous phase and has good interfacial bonding with the core, effectively preventing independent homogeneous nucleation and disordered stacking of Yb2Si2O7 nanoparticles. It should be noted that core-shell structured powders with different shell thicknesses can be prepared by adjusting the molar ratio of ytterbium source to silicon source.

[0076] like Figure 6 As shown, this embodiment of the invention also provides a core-shell structured granulated powder 200 prepared by step S104 of the above preparation method. Figure 6 The image shows a scanning electron microscope (SEM) image of SiO2@Yb2Si2O7 core-shell structure granulated powder 200. The results show that the core-shell structure granulated powder 200 is a regular sphere with uniform size. The particle size distribution of the core-shell structure granulated powder 200 is in the range of 30-80 μm, and it has excellent granulation powder properties.

[0077] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the appended claims.

Claims

1. A method for preparing core-shell structured ceramic powder, characterized in that, The method includes: The suspension is injected into the reaction chamber, and a suspension system containing SiO2 cores is formed under stirring and heating conditions; A ytterbium source solution and a supplementary silicon source solution are introduced into a suspension system containing SiO2. A pH regulator is added dropwise into the reaction chamber to guide the reaction products of the ytterbium source solution and the silicon source solution to deposit and grow on the surface of the SiO2 core, forming a core-shell structure precursor. The core-shell structure precursor is processed to obtain core-shell structured ceramic powder comprising SiO2@Yb2Si2O7.

2. The method for preparing core-shell structured ceramic powder according to claim 1, characterized in that, The method is implemented using a core-shell structured ceramic powder preparation system, which includes: The raw material conveying module includes a first silicon source storage tank, a second silicon source storage tank, a ytterbium salt storage tank, and a pH adjuster storage tank; A synthesis reaction module includes a reaction vessel with a reaction chamber. A silicon source microchannel and a ytterbium source microchannel are provided at the top of the reaction vessel and communicate with the reaction chamber. The silicon source microchannel is connected to a first silicon source storage tank and a second silicon source storage tank via pipelines. The ytterbium source microchannel is connected to a ytterbium salt storage tank via pipelines. A first pump is provided between the reaction vessel and the ytterbium salt storage tank. A second pump is provided on the pipeline between the reaction vessel and the first and second silicon source storage tanks. A stirring motor is provided at the top of the reaction vessel, and the stirring shaft of the stirring motor extends into the reaction chamber. A separation umbrella and a stirring mechanism are sequentially provided on the stirring shaft in a direction away from the top of the reaction vessel. The reaction chamber is connected to the pH regulator storage tank through a pipeline. A third pump body is provided on the pipeline between the reaction vessel and the pH regulator injection pump. A pH sensor extending into the reaction chamber is provided on the reaction vessel. The pH sensor is electrically connected to the third pump body to form a closed-loop control circuit. A first heat exchanger is provided in the reaction chamber. A heater is provided on the side of the first heat exchanger away from the reaction chamber. The processing module is connected to the product outlet of the reaction chamber and is used to process the reactants output from the product outlet into powder.

3. The method for preparing core-shell structured ceramic powder according to claim 2, characterized in that, The processing module includes a solid-liquid-gas separation unit, a solid-liquid separation unit, a water washing unit, an alcohol washing unit, a drying unit, a calcination unit, and a ball milling unit connected sequentially by pipelines. The preparation system also includes a recovery module, a pure water storage tank, an ethanol storage tank, and a waste liquid storage tank. The recovery module includes a second heat exchanger, a first membrane treatment unit, a second membrane treatment unit, and an evaporation unit. The second heat exchanger is connected to the first heat exchanger by pipelines. The first membrane treatment unit is connected to the alcohol washing unit by pipelines. The first membrane treatment unit is connected to the ethanol storage tank by pipelines. The solid-liquid separation unit is connected to the waste liquid storage tank by pipelines. The second membrane treatment unit is connected to the waste liquid storage tank by pipelines. The evaporation unit is connected to the second membrane treatment unit by pipelines. A first valve is installed on the pipeline between the ethanol storage tank and the second silicon source storage tank. A third valve and a fourth valve are installed on the pipeline between the pure water storage tank and the second silicon source storage tank.

4. The method for preparing core-shell structured ceramic powder according to claim 2, characterized in that, Injecting the suspension into a reaction vessel and forming a suspension system containing the SiO2 core under stirring and heating conditions includes: The suspension of SiO2 nuclei stored in the first silicon source storage tank is injected into the reactor. The stirring shaft of the stirring motor is driven to rotate. The stirring shaft drives the stirring mechanism to stir the suspension of SiO2 nuclei. At the same time, the heater is controlled to heat the suspension of SiO2 nuclei to form a suspension system containing SiO2 nuclei.

5. The method for preparing core-shell structured ceramic powder according to claim 2, characterized in that, Introducing a ytterbium source solution and a supplementary silicon source solution into a suspension system containing SiO2 includes: The ytterbium source solution stored in the ytterbium salt storage tank is introduced into the suspension system containing SiO2 through the first pump body, and the silicon source solution stored in the second silicon source storage tank is added to the suspension system through the second pump body. The system is initially mixed through the silicon source microchannel and the ytterbium source microchannel, and then further mixed through the tangential flow of the separation umbrella.

6. The method for preparing core-shell structured ceramic powder according to claim 2, characterized in that, The supplementary silicon source solution is an aqueous sodium silicate solution, the pH adjuster is ammonia, the reaction pH is 9-11, and the reaction temperature is 60-90℃; or the supplementary silicon source solution is an ethanol solution of tetraethyl orthosilicate, the pH adjuster is hydrochloric acid, and the reaction temperature is 70-85℃. The preparation system also includes a pure water storage tank and an ethanol storage tank. A first valve is provided on the pipeline between the ethanol storage tank and the second silicon source storage tank, and a third valve and a fourth valve are provided on the pipeline between the pure water storage tank and the second silicon source storage tank. Before introducing the ytterbium source solution and the supplementary silicon source solution into the suspension system containing SiO2, the method further includes: when the first valve is closed, the third valve is opened, and the fourth valve is opened, an aqueous sodium silicate solution is formed in the second silicon source storage tank; or when the first valve is opened and the fourth valve is closed, an ethanol solution of tetraethyl orthosilicate is formed in the second silicon source storage tank.

7. The method for preparing core-shell structured ceramic powder according to claim 2, characterized in that, The method further includes: when introducing the ytterbium source solution stored in the ytterbium salt storage tank and the silicon source solution stored in the second silicon source storage tank, adding a surface modifier to the ytterbium source solution and / or the silicon source solution, wherein the surface modifier is polyvinylpyrrolidone, polyvinyl alcohol or a silane coupling agent.

8. The method for preparing core-shell structured ceramic powder according to claim 2, characterized in that, Processing the core-shell structure precursor to obtain core-shell structured ceramic powder includes: The core-shell structure precursor is subjected to solid-liquid separation, washing, drying, calcination at 1200-1500℃ for 1-5 hours, and ball milling through a processing module to form the core-shell structure ceramic powder comprising SiO2@Yb2Si2O7.

9. The method for preparing core-shell structured ceramic powder according to claim 1, characterized in that, The method further includes: preparing the core-shell structured ceramic powder including SiO2@Yb2Si2O7 with a binder into a slurry and then performing spray granulation to obtain core-shell structured granulated powder including SiO2@Yb2Si2O7.

10. A core-shell structured ceramic powder, characterized in that, The core-shell structured ceramic powder is prepared by the method described in any one of claims 1-9, and includes a core and a shell, wherein the material of the core is SiO2 and the material of the shell is Yb2Si2O7.

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