Solid waste-based gradient porous ceramic self-repairing high thermal shock resistance heat storage material and preparation method

Abstract

The application provides a solid waste-based gradient porous ceramic self-repairing high thermal shock resistance heat storage material and a preparation method. The heat storage material is in a spherical structure or a honeycomb structure. The heat storage material comprises a surface layer, a transition layer and an inner layer from outside to inside. The porosity of the surface layer is less than that of the inner layer. The density of the transition layer continuously changes in the direction from the surface layer to the transition layer. The heat storage material is internally provided with a second phase nanoparticle self-repairing system loaded with FeO / graphene double metal oxide. The nanoparticle is a FeO nanosheet with a surface containing -COOH and -OH functional groups. The application uses solid waste as a main raw material, adopts a gradient structure, nanometer enhancement and an in-situ self-repairing mechanism and other technologies, and can not only provide excellent thermal shock stability, but also realize a crack self-repairing heat storage material, improve the comprehensive performance of the storage material and solve the problem of serious damage of the heat storage material for a high-temperature kiln.

Description

Technical Field

[0001] The embodiments of the present invention belong to the field of high-temperature thermal storage technology, specifically relating to a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material and its preparation method. Background Technology

[0002] In the field of energy storage and conversion technology, thermal storage materials play a crucial role, especially in the utilization and storage of high-temperature thermal energy.

[0003] However, traditional thermal storage materials, such as magnesia bricks, often suffer from irreversible crack propagation due to thermal stress during repeated thermal cycles, leading to a sharp decline in material performance and severely limiting their service life and thermal efficiency.

[0004] For example, reference patent CN116102325A proposes a water-repairing self-healing kitchen and bathroom backfill mortar, which achieves self-repair of cracks when water penetrates by adding self-healing capsules to the mortar.

[0005] However, this self-healing mechanism is only applicable to waterproof systems in specific environments and cannot be directly applied to high-temperature thermal cycling conditions. Furthermore, its repair principle is different from the chemical reaction mechanism required for high-temperature crack repair.

[0006] Another reference patent, CN114941964A, relates to a gradient-connected three-dimensional prestressed ceramic composite armor, which improves the armor's anti-penetration capability through a gradient composite structure of ceramic and metal.

[0007] While the gradient structure design in the patent alleviates the thermal stress problem to some extent, its main purpose is to enhance the protective performance of the armor, rather than to solve the problem of repairing thermal shock cracks at high temperatures. Summary of the Invention

[0008] The embodiments of the present invention aim to at least solve one of the technical problems existing in the prior art, and provide a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material and its preparation method.

[0009] One embodiment of the present invention provides a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material. The thermal storage material has a spherical structure or a honeycomb structure. The thermal storage material includes a surface layer, a transition layer and an inner layer from the outside to the inside. The porosity of the surface layer is less than that of the inner layer. The density of the transition layer changes continuously in a gradient along the direction from the surface layer to the transition layer. The thermal storage material incorporates a second-phase nanoparticle self-healing system supported by FeO / graphene bimetallic oxide, wherein the nanoparticles are FeO nanosheets with -COOH and -OH functional groups on their surface and a size of 50-200 nm.

[0010] In some embodiments of this disclosure, the porosity of the surface layer is 15-20%, and the porosity of the inner layer is 75-85%.

[0011] In some embodiments of this disclosure, the thickness of the surface layer is 4-6 mm, and the thickness of the inner layer is 40-50 mm.

[0012] This disclosure also proposes a method for preparing a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material as described in any of the above embodiments, comprising: S1: Mix and grind solid waste, sintering aid, and foaming agent, then add water and glass powder and ball mill to make a slurry; S2: The slurry is poured in layers through a plaster mold, and after vibration to drain the water, it is left to stand at room temperature to set. S3: Segmented sintering forms a solid waste-based gradient porous ceramic matrix; S4: KCl-NaCl double salt aqueous solution is injected into the center of the matrix by template printing, dried and sealed to obtain solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material.

[0013] In some embodiments of this disclosure, step S2, layered casting includes at least three gradient slurry castings, with vibration drainage for 10-15 minutes after each casting.

[0014] In some embodiments of this disclosure, step S3, segmented sintering, includes: First stage sintering: calcination temperature 400-700℃, calcination time 12h; Second stage sintering: calcination temperature 1000-1300℃, calcination time 2h; The third stage of sintering: calcination temperature 900-1100℃, calcination time 24h.

[0015] In some embodiments of this disclosure, step S3, segmented sintering, includes: First stage sintering: calcination temperature 500-700℃, calcination time 1h; Second stage sintering: calcination temperature 900-1100℃, calcination time 2-4h; The third stage of sintering: calcination temperature 1200-1400℃, calcination time 6-8h; Fourth stage sintering: calcination temperature 1500-1700℃, calcination time 2h; Fifth stage sintering: calcination temperature 1400-1600℃, calcination time 2h.

[0016] In some embodiments of this disclosure, in step S4, the KCl molar concentration of the complex salt aqueous solution is 0.08 mol / L, and the mullite powder particle size is ≤50 μm.

[0017] In some embodiments of this disclosure, in step S5, the template printing uses a porous ceramic special template with a pore diameter matching degree of 90±5% with the inner cavity pore size.

[0018] In some embodiments of this disclosure, in step S5, the drying temperature is 400-500°C and the drying time is 1 hour.

[0019] The present invention relates to a solid waste-based gradient porous ceramic self-healing high thermal shock resistant heat storage material and its preparation method. The material is prepared using a gradient structure + nano-reinforcement + in-situ self-healing mechanism. This heat storage material can be used for storing high-temperature waste heat from industrial kilns and has the following beneficial effects: (1) The energy storage density of the solid waste-based gradient porous ceramic can reach 1.0-1.5 kJ / g; (2) The thermal stress damage of the porous ceramic with the second-order gradient structure is significantly lower than that of the ceramic with the gradient structure without the step transition; (3) The damage after the introduction of the in-situ self-healing mechanism is significantly lower than that of the corresponding group without the introduction of the in-situ self-healing mechanism; (4) The designed self-healing mechanism has periodic self-healing characteristics. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material of the present invention; Figure 2 This is a flowchart illustrating the preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material of the present invention.

[0021] Figure label: 1. Surface layer; 2. Inner layer; 3. Transition layer; 4. Porous structure. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit disclosure. The described embodiments are some, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] One embodiment of the present invention provides a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material. The thermal storage material has a spherical structure or a honeycomb structure. The thermal storage material includes a surface layer 1, a transition layer 3 and an inner layer 2 from the outside to the inside. The porosity of the surface layer 1 is less than that of the inner layer 2. The density of the transition layer 3 changes continuously in a gradient along the direction from the surface layer 1 to the transition layer 3. The thermal storage material incorporates a second-phase nanoparticle self-healing system supported by FeO / graphene bimetallic oxide, wherein the nanoparticles are FeO nanosheets with -COOH and -OH functional groups on their surface and a size of 50-200 nm.

[0024] This invention relates to a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material and its preparation method. The material is prepared using a gradient structure, nano-reinforcement, and an in-situ self-healing mechanism. The energy storage density of the solid waste-based gradient porous ceramic can reach 1.0-1.5 kJ / g. The thermal stress damage of the porous ceramic with a second-order gradient structure is significantly lower than that of ceramics without a gradient structure transition. The damage after introducing the in-situ self-healing mechanism is significantly lower than that of the corresponding group without the in-situ self-healing mechanism. The designed self-healing mechanism has periodic self-healing characteristics. The thermal storage material can be used for storing high-temperature waste heat from industrial kilns.

[0025] In some embodiments of this disclosure, a plurality of pore structures 4 are formed on the thermal storage material, and the porosity of the pore structures 4 of the surface layer 1 and the pore structures 4 of the inner layer 2 are different.

[0026] In some embodiments of this disclosure, the porosity of the surface layer 1 is 15-20%, and the porosity of the inner layer 2 is 75-85%.

[0027] In some embodiments of this disclosure, the thickness of the outer layer 1 is 4-6 mm, and the thickness of the inner layer 2 is 40-50 mm.

[0028] This disclosure also proposes a method for preparing a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material as described in any of the above embodiments, comprising: S1: Mix and grind solid waste, sintering aid, and foaming agent, then add water and glass powder and ball mill to make a slurry; S2: The slurry is poured in layers through a plaster mold, and after vibration to drain the water, it is left to stand at room temperature to set. S3: Segmented sintering forms a solid waste-based gradient porous ceramic matrix; S4: KCl-NaCl double salt aqueous solution is injected into the center of the matrix by template printing, dried and sealed to obtain solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material.

[0029] In some embodiments of this disclosure, step S2, layered casting includes at least three gradient slurry castings, with vibration drainage for 10-15 minutes after each casting.

[0030] In some embodiments of this disclosure, step S3, segmented sintering, includes: First stage sintering: calcination temperature 400-700℃, calcination time 12h; Second stage sintering: calcination temperature 1000-1300℃, calcination time 2h; The third stage of sintering: calcination temperature 900-1100℃, calcination time 24h.

[0031] In some embodiments of this disclosure, step S3, segmented sintering, includes: First stage sintering: calcination temperature 500-700℃, calcination time 1h; Second stage sintering: calcination temperature 900-1100℃, calcination time 2-4h; The third stage of sintering: calcination temperature 1200-1400℃, calcination time 6-8h; Fourth stage sintering: calcination temperature 1500-1700℃, calcination time 2h; Fifth stage sintering: calcination temperature 1400-1600℃, calcination time 2h.

[0032] In some embodiments of this disclosure, in step S4, the KCl molar concentration of the complex salt aqueous solution is 0.08 mol / L, and the mullite powder particle size is ≤50 μm.

[0033] In some embodiments of this disclosure, in step S4, the template printing uses a porous ceramic special template with a pore diameter matching degree of 90±5% with the inner cavity pore size.

[0034] In some embodiments of this disclosure, in step S4, the drying temperature is 400-500°C and the drying time is 1 hour.

[0035] The present invention relates to a solid waste-based gradient porous ceramic self-healing high thermal shock resistant heat storage material and its preparation method. The material is prepared using a gradient structure + nano-reinforcement + in-situ self-healing mechanism. This heat storage material can be used for storing high-temperature waste heat from industrial kilns and has the following beneficial effects: (1) The energy storage density of the solid waste-based gradient porous ceramic can reach 1.0-1.5 kJ / g; (2) The thermal stress damage of the porous ceramic with the second-order gradient structure is significantly lower than that of the ceramic with the gradient structure without the step transition; (3) The damage after the introduction of the in-situ self-healing mechanism is significantly lower than that of the corresponding group without the introduction of the in-situ self-healing mechanism; (4) The designed self-healing mechanism has periodic self-healing characteristics.

[0036] Example 1 I. Preparation methods include: S1: Raw material pretreatment and mixing Coal gangue, fly ash, and fluorite tailings are ground separately, with the particle size controlled below 200 mesh, and then thoroughly mixed. After mixing, a polyvinyl alcohol aqueous solution is added for uniform granulation. In this invention, the polyvinyl alcohol aqueous solution has a concentration of 4-6% and a mass fraction of 3-4%.

[0037] S2: Molding process The granules are dry-pressed into a green body.

[0038] S3: Segmented sintering: To prevent the billet from cracking, heat the billet from room temperature to 500-700°C at a rate not exceeding 5°C / min and hold for 1 hour. The temperature is increased from 500-700°C to 900-1100°C at a rate not exceeding 7°C / min, and held at 900-1100°C for 2-4 hours to promote the sintering of the green body. The temperature is increased from 900-1100°C to 1200-1400°C at a rate not exceeding 5°C / min, and held at 1200-1400°C for 6-8 hours to complete the hardening stage. The temperature is increased from 1200-1400°C to 1500-1700°C at a rate of not less than 15°C / min, and held for 2 hours to promote the precipitation and expansion of bubbles inside the green body.

[0039] After cooling, the blank is demolded to obtain the unfinished blank; The unglazed blanks are placed in a kiln and kept at 1400-1600°C for 2 hours, then naturally cooled to room temperature to complete the debinding and firing.

[0040] S4: Introduction of self-repair mechanism KCl and NaCl were dissolved in deionized water, and then mullite powder and phosphoric acid were added. After ball milling for 30 minutes, the mixture was filtered and dried to obtain a complex salt aqueous solution. The complex salt aqueous solution was injected into the cavity of a solid waste-based gradient porous ceramic matrix using a template printing method. The matrix was dried in an environment of 400-500℃ and then sealed for storage to obtain a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material.

[0041] Example 2 I. Preparation methods include: S1: Raw material pretreatment and mixing Grind coal gangue, fly ash, and fluorite tailings to below 200 mesh (particle size ≤75μm) and mix them in a certain proportion. Add sintering aid (kaolin), foaming agent (magnesium carbonate:silicon carbide = 1:10), and 4-6% polyvinyl alcohol aqueous solution to granulate uniformly.

[0042] S2: Molding process The plaster mold is used to pour the plaster in multiple layers, with vibration to assist drainage, and then let it stand at room temperature for 12 hours to initially form the plaster.

[0043] S3: Segmented sintering Precision temperature control process: 600°C → 1000°C (hold for 2 hours) → 1300°C (hold for 2 hours) → 1150°C (hold for 4 hours) → 850°C (hold for 4 hours) → 550°C (hold for 2 hours) → 350°C (hold for 4 hours) → 230°C (hold for 2 hours) → 150°C (hold for 4 hours) → 70°C (hold for 4 hours) S4: KCl and NaCl are dissolved in deionized water, then mullite powder and phosphoric acid are added. After ball milling for 30 minutes, the mixture is filtered and dried to obtain a complex salt aqueous solution. The complex salt aqueous solution is injected into the cavity of a solid waste-based gradient porous ceramic matrix using a template printing method. The matrix is ​​dried in an environment of 400-500℃ and then sealed for storage to obtain a solid waste-based gradient porous ceramic self-healing high thermal shock resistant heat storage material.

[0044] Table 1. Performance comparison of thermal storage materials in Example 2 with existing technologies.

[0045] As shown in Table 1, the thermal storage material of Example 2 has more than 5 times the number of cycles compared with traditional materials (from 10-20 times to >100 times), and its thermal shock resistance is improved by 400-500%; the thermal storage capacity per unit mass of the thermal storage material of Example 2 is increased by about 70%-90%; the temperature resistance of the thermal storage material of Example 2 is increased from 1400℃ to 1700℃ (+21%), which can adapt to more extreme thermal environments; the service life of the thermal storage material of Example 2 is extended by 4-5 times (from 500-1000 cycles to 3000-5000 cycles); and the cost of the thermal storage material of Example 2 is reduced by 30%-40%, which has an economic advantage.

[0046] This invention utilizes solid waste as the main raw material and employs technologies such as gradient structure, nano-reinforcement, and in-situ self-healing mechanism to create a heat storage material that not only has excellent thermal shock stability but also enables self-healing of cracks, thereby improving the overall performance of the storage material and solving the problem of severe damage to heat storage materials used in high-temperature kilns.

[0047] By introducing a self-healing mechanism from industrial waste salt and a gradient porous + nano-reinforced composite structure, the thermal stress cracking problem of thermal storage materials under high-temperature thermal cycling conditions is solved, significantly improving the thermal shock stability and service life of the materials.

[0048] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material, characterized in that, The thermal storage material has a spherical or honeycomb structure. The thermal storage material includes a surface layer, a transition layer and an inner layer from the outside to the inside. The porosity of the surface layer is less than that of the inner layer. The density of the transition layer changes continuously in a gradient along the direction from the surface layer to the transition layer. The thermal storage material incorporates a second-phase nanoparticle self-healing system supported by FeO / graphene bimetallic oxide, wherein the nanoparticles are FeO nanosheets with -COOH and -OH functional groups on their surface and a size of 50-200 nm.

2. The solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 1, characterized in that, The porosity of the surface layer is 15-20%, and the porosity of the inner layer is 75-85%.

3. The solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 1, characterized in that, The outer layer has a thickness of 4-6 mm, and the inner layer has a thickness of 40-50 mm.

4. A method for preparing a solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material as described in any one of claims 1-3, characterized in that, include: S1: Mix and grind solid waste, sintering aid, and foaming agent, then add water and glass powder and ball mill to make a slurry; S2: The slurry is poured in layers through a plaster mold, and after vibration to drain the water, it is left to stand at room temperature to set, or it is formed by dry pressing. S3: Segmented sintering forms a solid waste-based gradient porous ceramic matrix; S4: KCl-NaCl double salt aqueous solution is injected into the center of the matrix by template printing, dried and sealed to obtain solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material.

5. The preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 4, characterized in that, In step S2, the layered pouring includes at least three gradient slurry pours, with vibration drainage for 10-15 minutes after each pour.

6. The preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 4, characterized in that, In step S3, segmented sintering includes: First stage sintering: calcination temperature 400-700℃, calcination time 12h; Second stage sintering: calcination temperature 1000-1300℃, calcination time 2h; The third stage of sintering: calcination temperature 900-1100℃, calcination time 24h.

7. The preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 4, characterized in that, In step S3, segmented sintering includes: First stage sintering: calcination temperature 500-700℃, calcination time 1h; Second stage sintering: calcination temperature 900-1100℃, calcination time 2-4h; The third stage of sintering: calcination temperature 1200-1400℃, calcination time 6-8h; Fourth stage sintering: calcination temperature 1500-1700℃, calcination time 2h; Fifth stage sintering: calcination temperature 1400-1600℃, calcination time 2h.

8. The preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 4, characterized in that, In step S4, the KCl molar concentration of the double salt aqueous solution is 0.08 mol / L, and the mullite powder particle size is ≤50 μm.

9. The preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 4, characterized in that, In step S4, the template printing uses a porous ceramic special template with a pore diameter matching degree of 90±5% with the inner cavity pore size.

10. The preparation method of the solid waste-based gradient porous ceramic self-healing high thermal shock resistant thermal storage material according to claim 4, characterized in that, In step S4, the drying temperature is 400-500℃ and the drying time is 1 hour.

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