Zirconia hollow sphere ultra-high temperature furnace lining material and preparation method thereof

Abstract

This invention discloses a zirconia hollow sphere ultra-high temperature furnace lining material and its preparation method, belonging to the technical field of ultra-high temperature ceramic materials. The preparation method of the zirconia hollow sphere ultra-high temperature furnace lining material is as follows: 85-95 parts of zirconia powder, 5-25 parts of alumina powder, and 3-5 parts of yttrium oxide powder are melted and blown in a three-phase electric arc furnace to obtain zirconia hollow sphere aggregate; 60-75 parts of zirconia hollow sphere aggregate, 4-18 parts of zirconia powder, 12-30 parts of alumina powder, and 2-5 parts of binder are mixed evenly, pressed, and sintered to obtain the zirconia hollow sphere lining material. This invention obtains the zirconia hollow sphere lining material through raw material melting and blowing, pressing, and sintering; the lining material has the characteristics of high strength, good creep resistance, good thermal shock stability, and high fracture toughness; the preparation method has a short process and high efficiency, which is conducive to large-scale industrial production and promotion.

Description

Technical Field

[0001] This invention relates to the field of ultra-high temperature furnace lining materials, specifically to a zirconia hollow sphere ultra-high temperature furnace lining material and its preparation method. Background Technology

[0002] Alumina hollow spherical bricks, mullite bricks, and zirconia refractory materials are currently the mainstream lining materials for industrial high-temperature kilns, playing a crucial role in extending the service life of high-temperature furnace linings. While alumina hollow spherical bricks and mullite bricks possess excellent thermal insulation and mechanical properties, their service temperature typically does not exceed 1750℃, making them unsuitable for ultra-high-temperature kilns. Although pure zirconia products have higher service temperatures (>2700℃), their high bulk density and thermal conductivity result in insufficient long-term thermal shock stability, hindering their ability to meet long-term service requirements and posing a challenge to the long-term continuous production of high-temperature kilns. With technological advancements, ultra-high-temperature ceramic materials with sintering temperatures exceeding 1800℃ are playing an increasingly important role in aerospace, military technology, and other fields. However, long-life furnace lining refractory materials for ultra-high-temperature kilns with service temperatures exceeding 1800℃ are rarely reported. Therefore, there is an urgent need to develop a lining material suitable for ultra-high-temperature kilns, meeting the needs of industrial-scale ultra-high-temperature ceramic production.

[0003] Alumina is a commonly used reinforcing phase in zirconia ceramics. Alumina-reinforced zirconia ceramics exhibit extremely high service temperatures and mechanical properties, making them a key research focus in high-temperature and ultra-high-temperature ceramics. Current research generally focuses on directly adding alumina components to create a pinning effect in zirconia ceramics, achieving strength and toughness, but with limited improvement on thermal shock stability. A deficiency in current research lies in the limited reports on optimizing the performance of ceramic matrix composites through the control of their crystal structure and morphology. Furthermore, current research primarily focuses on dense zirconia-alumina ceramics with extremely high thermal conductivity. Therefore, there is an urgent need to optimize and improve the composition and structure of zirconia-alumina ceramics to meet the requirements of service under ultra-high temperature conditions.

[0004] Chinese patents CN201080059614.7 and CN201710203420.3 disclose two methods for preparing high-strength alumina ceramics. The core idea is to add appropriate amounts of SiO2, MgO, and CaO as sintering aids to the α-Al2O3 component, or to add silicon carbide whiskers to improve the sintering degree or toughness of the alumina ceramic. However, the addition of various sintering aids is detrimental to the high-temperature performance of alumina ceramics and worsens their creep performance during high-temperature service. While adding one-dimensional micro / nanomaterials such as silicon carbide whiskers as the main means of toughening ceramic fibers still suffers from problems such as uneven dispersion during preparation and oxidation of silicon carbide whiskers during service. Therefore, the mechanical properties of the prepared alumina-based ceramic materials still cannot meet service requirements.

[0005] Chinese patent CN102712542A discloses a zirconia-alumina composite ceramic material and its preparation method, including the following steps: selecting zirconia composite powder and alumina powder, and obtaining zirconia-alumina composite material through tape casting and sintering. Its essence is to toughen zirconia ceramic by introducing nano-sized alumina particles to enhance the pinning effect of alumina in zirconia ceramic. However, the crystal structure of the composite ceramic material is not designed, resulting in limited toughening effect.

[0006] Chinese patent CN106946574A discloses a high-purity, high-strength zirconia-alumina composite ceramic material and its preparation method, comprising the following steps: mixing a zirconium-containing compound, a yttrium-containing compound, and a solvent for a solvothermal reaction, calcining to obtain yttrium-stabilized zirconia powder, and forming it into a zirconia ceramic preform; adding a sintering aid to multiphase alumina powder, mixing and forming it into an alumina ceramic preform; and preparing the stacked zirconia-alumina ceramic by laminating, pressing, and co-firing the zirconia and alumina ceramic preforms. The layered structure can improve the fracture toughness of the ceramic perpendicular to the layered direction, but at the same time reduces the mechanical properties parallel to the layered direction.

[0007] Chinese patent CN115894056A discloses a method for preparing a three-dimensional alumina fiber-reinforced zirconia ceramic composite material, including the following steps: impregnating a slurry containing zirconia into a three-dimensionally woven alumina product, followed by curing and sintering to obtain alumina-toughened zirconia ceramic. The core principle is to utilize the alumina fibers of the fiber piles to toughen the zirconia ceramic. However, the three-dimensionally woven alumina fibers are not uniformly dispersed in the zirconia ceramic matrix, resulting in a relatively limited toughening effect on the ceramic material.

[0008] Chinese patent CN106518028A discloses a method for preparing micro / nano zirconia / alumina composite materials, including the following steps: ball milling an appropriate amount of submicron-sized lightly calcined ZrO2 powder and Al2O3 powder, then adding a binder, dry pressing, and cold isostatic pressing to obtain zirconia-alumina multiphase ceramic. This method is not only complex and costly, but the ZrO2 grains are also randomly distributed in the Al2O3 matrix, making it difficult to maximize the toughening effect.

[0009] Chinese patent CN115947597B discloses a method for preparing closed-cell lightweight zirconia ceramics, comprising the following steps: mixing fused zirconia, chemically synthesized zirconia, and a pore-forming agent, molding, and sintering to obtain lightweight zirconia ceramics. This method is not significantly different from conventional lightweight refractory materials prepared using pore-forming agents, and it cannot control the pore structure of the closed-cell lightweight zirconia ceramics, making it difficult to effectively improve its thermal shock resistance and mechanical properties. Summary of the Invention

[0010] To address the challenges in the preparation of zirconia-alumina composite ceramic materials, such as the difficulty in achieving synergistic optimization and improvement of thermal insulation and thermal shock stability, the lack of effective design of the crystal structure of ultra-high temperature zirconia lining materials, the insignificant toughening effect, and the low high-temperature mechanical properties, this invention provides a zirconia hollow sphere ultra-high temperature furnace lining material and its preparation method that can solve the aforementioned technical problems.

[0011] This invention provides a zirconia hollow sphere ultra-high temperature furnace lining material, made from the following raw materials in parts by weight: 60-75 parts zirconia hollow sphere aggregate, 4-18 parts zirconia powder, 12-30 parts alumina powder, and 2-5 parts binder; wherein:

[0012] The zirconium oxide powder is one of calcium-stabilized zirconium oxide, magnesium-stabilized zirconium oxide, and yttrium-stabilized zirconium oxide, with a zirconium oxide particle size ≤0.088mm and a ZrO2 content ≥90wt%.

[0013] The alumina powder is a plate-shaped corundum fine powder with a particle size ≤0.088mm and an Al2O3 content ≥90wt%.

[0014] The zirconia hollow sphere aggregate comprises the following components by weight: 85-95 parts zirconia powder, 5-25 parts alumina powder, and 3-5 parts yttrium oxide powder;

[0015] The adhesive is an aqueous solution containing 5-10 wt% organic matter, which is selected from at least one of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, carrageenan, and starch.

[0016] Furthermore, in the components of the zirconium oxide hollow sphere aggregate: the particle size of zirconium oxide powder is ≤10μm and the purity is ZrO2≥99wt%; the particle size of alumina powder is ≤10μm and the purity is Al2O3≥99wt%; the particle size of yttrium oxide powder is ≤10μm and the purity is Y2O3≥99wt%.

[0017] Furthermore, the particle size distribution of the zirconia hollow sphere aggregate satisfies the following: hollow spheres with a particle size of 3-5 mm account for 40-50 wt% of the total weight of the hollow sphere aggregate, hollow spheres with a particle size of 1-3 mm account for 25-40 wt% of the total weight of the hollow sphere aggregate, and hollow spheres with a particle size of 0.1-1 mm account for 10-25 wt% of the total weight of the hollow sphere aggregate.

[0018] Furthermore, the porosity of the hollow zirconia spheres is ≥70%, and the wall thickness of the hollow spheres is 0.1–0.8 mm.

[0019] Furthermore, the microstructure of the zirconia hollow sphere aggregate is a eutectic structure in which elongated or columnar zirconia grains are randomly interspersed in alumina grains, with the alumina grain size being 500–5000 nm and the zirconia grain size being 50–2000 nm.

[0020] Furthermore, the zirconia hollow sphere ultra-high temperature furnace lining material meets the following performance indicators: porosity of 20-30%, compressive strength of 70-100 MPa, flexural strength of 8-12 MPa, high-temperature flexural strength at 1400℃ of 6-8 MPa, thermal conductivity range of 0.8-1.6 W / m·K, maximum operating temperature of 2000-2300℃, and compression creep of 0.01-0.03% under the conditions of 1400℃, 100 MPa, and 600 min.

[0021] This invention also provides a method for preparing the above-mentioned ultra-high temperature furnace lining material, comprising the following steps:

[0022] S1. Alumina powder, zirconium oxide powder, and yttrium oxide powder are added to a three-phase electric arc furnace in proportion and heated to melt. The molten solution is then sprayed to form hollow spheres, cooled, and sieved to obtain zirconium oxide hollow sphere aggregate.

[0023] S2. Mix 60-75 parts of the zirconia hollow sphere aggregate obtained in step S1 with 4-18 parts of zirconia powder, 12-30 parts of alumina powder, and 2-5 parts of binder evenly, press into shape, dry and fire to obtain zirconia hollow sphere ultra-high temperature furnace lining material.

[0024] Furthermore, in step S1, during the melt spraying process, the melting temperature is 2200-2500℃ and the spraying pressure is 0.6-1.0MPa.

[0025] Further, in step S1, after the hollow spheres have cooled to room temperature, they are sieved through sieves with particle sizes of 3-5 mm, 1-3 mm, and 0.1-1 mm to obtain zirconium oxide hollow sphere aggregates with particle sizes of 3-5 mm, 1-3 mm, and 0.1-1 mm, respectively.

[0026] Furthermore, in step S2, the molding pressure is 50–100 MPa, the drying temperature is 80–110°C, the drying time is 24–36 h, the firing temperature is 1600–1800°C, and the firing time is 3–6 h.

[0027] The main toughening method for current zirconia ceramic matrix composites is to introduce an alumina phase, utilizing its pinning effect during sintering to achieve toughening. However, alumina, as a second phase added to zirconia-based ceramics, exhibits a random distribution, and its crystal microstructure is difficult to control and design through direct introduction, resulting in a limited toughening effect. On the other hand, dense ceramics have excessively high thermal conductivity. Although increasing porosity can reduce thermal conductivity, the resulting decrease in mechanical properties further leads to a decline in thermal shock stability. Therefore, balancing the relationship between mechanical properties, thermal insulation properties, and thermal shock stability to prepare ultra-high temperature furnace lining materials with excellent comprehensive performance is a current research focus and challenge.

[0028] Aggregates form the skeleton of furnace lining refractory materials and are crucial to the material's mechanical properties. Using a three-phase electric arc furnace for molten blowing allows zirconia and alumina crystals to co-precipitate, forming micro-nano-scale alumina crystal pillars interspersed within the zirconia crystals. This maximizes the toughening and mechanical property improvement of the zirconia hollow sphere aggregate at the microscale, thereby enhancing the overall high-temperature stability of the hollow sphere bricks and improving their high-temperature mechanical properties and creep resistance. Furthermore, the hollow structure inside the zirconia-based hollow spheres produced by molten blowing helps alleviate or avoid the concentration of thermal or mechanical stress, significantly improving thermal conductivity and thermal shock resistance.

[0029] This invention proposes a zirconia hollow sphere ultra-high temperature furnace lining material and its preparation method, which can solve the problems in the preparation of zirconia-alumina composite ceramic materials, such as the difficulty in achieving synergistic optimization and improvement of thermal insulation performance and thermal shock stability, the lack of effective design of crystal structure of ultra-high temperature zirconia lining materials, the insignificant toughening effect, and the low high temperature mechanical properties. Compared with the prior art, this invention has at least the following beneficial effects:

[0030] (1) In the preparation process, the present invention uses zirconia hollow spheres as aggregates and zirconia powder and alumina powder as matrices to press into lining materials. The hollow spheres serve as a skeleton structure to support the furnace lining material, thus ensuring the overall mechanical and thermal properties of the material.

[0031] (2) The present invention prepares zirconia hollow spheres by melt blowing technology. During the high-temperature melting process, the zirconia crystals and alumina crystals are co-precipitated by blowing. The wall thickness and particle size of the hollow spheres are controlled by the melting temperature and blowing pressure. Zirconia hollow spheres with eutectic structure can be obtained relatively easily, thereby improving the mechanical properties and thermal shock stability of the material while reducing the thermal conductivity of the hollow spheres.

[0032] (3) The present invention can relatively easily obtain alumina-toughened zirconia hollow sphere alumina-zirconia eutectic ceramics, while controlling the morphology of alumina grains and zirconia grains in the eutectic ceramics to optimize and improve the thermal expansion coefficient, fracture toughness and other properties of the eutectic dense ceramics.

[0033] (4) The zirconia hollow sphere ultra-high temperature furnace lining material prepared by the present invention has low cost and simple process, and is suitable for large-scale mass production.

[0034] In summary, compared with traditional technologies, this invention obtains zirconia hollow sphere ultra-high temperature furnace lining material through raw material powder melting and blowing, compact preparation, and high-temperature sintering. Its porosity is 20-30%, compressive strength is 70-100 MPa, flexural strength is 8-12 MPa, high-temperature flexural strength at 1400℃ is 6-8 MPa, thermal conductivity ranges from 0.8-1.6 W / m·K, maximum operating temperature is 2000-2300℃, and compression creep is 0.01-0.03% under conditions of 1400℃, 100 MPa, and 600 min. This zirconia hollow sphere ultra-high temperature furnace lining material has the characteristics of high strength, good thermal shock stability, high fracture toughness, excellent creep performance, and good thermal insulation performance, significantly improving the material's mechanical properties and fracture toughness. The preparation process is simple, short, and efficient, facilitating large-scale industrial production and promotion, and has good application prospects in fields such as ultra-high temperature structural ceramics. Attached Figure Description

[0035] Figure 1 Figure 1 shows a microstructure of zirconia hollow spheres in an ultra-high temperature furnace lining material according to Embodiment 1 of the present invention; wherein, Figure a is a microstructure of the hollow spheres after firing, and Figure b is a further magnified microstructure.

[0036] Figure 2 Figure 1 shows a microstructure of zirconia hollow spheres in an ultra-high temperature furnace lining material of zirconia hollow spheres according to Embodiment 1 of the present invention; wherein, Figure a is a crystal structure diagram of the hollow spheres after firing, and Figure b is a further magnified crystal structure diagram.

[0037] Figure 3 Figure 1 shows a microstructure of a zirconia hollow sphere ultra-high temperature furnace lining material according to Embodiment 1 of the present invention; wherein, Figure a is a microstructure of the material after sintering, and Figure b is a further magnified microstructure. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment discloses a zirconia hollow sphere ultra-high temperature furnace lining material, comprising 75 parts of zirconia hollow sphere aggregate, 18 parts of zirconia powder, 12 parts of alumina powder, and 5 parts of binder. The zirconia powder is calcium-stabilized zirconia powder with a particle size ≤0.088mm and a ZrO2 content ≥90wt%. The alumina powder is plate-shaped corundum fine powder with a particle size ≤0.088mm and an Al2O3 content ≥90wt%.

[0041] This embodiment provides a method for preparing ultra-high temperature furnace lining material based on the aforementioned zirconia hollow sphere material, which specifically includes the following steps:

[0042] The preparation method of zirconia hollow spheres is as follows: First, 95 parts of zirconia powder, 10 parts of alumina powder, and 5 parts of yttrium oxide powder are placed in a three-phase electric arc furnace and heated to 2500℃ for 0.5h to obtain a molten mixture of zirconia, alumina, and yttrium oxide. Then, the molten mixture in the three-phase electric arc furnace is poured into a guide trough and sprayed into zirconia hollow spheres under a gas pressure of 0.6MPa. After the hollow spheres are cooled to room temperature, they are sieved through sieves of 5-3 mm, 3-1 mm, and 1-0.1 mm to obtain zirconia hollow sphere aggregates with particle sizes of 5-3 mm, 3-1 mm, and 1-0.1 mm, respectively.

[0043] The preparation method of zirconia hollow sphere ultra-high temperature furnace lining material is as follows: First, 75 parts of zirconia hollow sphere aggregate, 18 parts of zirconia powder, and 12 parts of alumina powder are mixed evenly, and then 5 parts of polyvinyl alcohol solution with an organic matter concentration of 5wt% are added. After stirring evenly, the mixture is pressed into a mixed compact under a molding pressure of 100MPa. The mixed compact is then subjected to high-temperature heat treatment at 1700℃ for 3 hours to obtain zirconia hollow sphere ultra-high temperature furnace lining material.

[0044] In this embodiment, the particle size distribution of the hollow zirconia spheres in the ultra-high temperature liner material is as follows: 50 wt% of the hollow spheres have a particle size of 3-5 mm, 35 wt% have a particle size of 1-3 mm, and 15 wt% have a particle size of 0.1-1 mm; the porosity of the hollow zirconia spheres is ≥85%, and the wall thickness of the hollow spheres is 0.8 mm. The microstructure of the prepared hollow zirconia spheres is characterized by columnar zirconia grains randomly interspersed within alumina grains, with the alumina grain size being 500 nm and the zirconia grain size being 100 nm.

[0045] The zirconia hollow sphere ultra-high temperature liner material prepared in this embodiment has a porosity of 20%, a compressive strength of 100 MPa, a flexural strength of 12 MPa, a high-temperature flexural strength of 8 MPa at 1400℃, a thermal conductivity range of 1.6 W / m·K, a maximum operating temperature of 2300℃, and a compression creep of 0.01% under the conditions of 1400℃, 100 MPa, and 600 min.

[0046] Figure 1 The diagram shows the microstructure of the zirconia hollow spheres in the ultra-high temperature furnace lining material prepared in this embodiment; wherein, Figure a is the microstructure of the hollow spheres after sintering, and Figure b is a further magnified microstructure.

[0047] Figure 2 The microstructure of the zirconia hollow spheres in the ultra-high temperature furnace lining material prepared in this embodiment is shown; wherein, Figure a is the crystal structure diagram of the hollow spheres after sintering, and Figure b is the crystal structure diagram after further magnification.

[0048] Figure 3 The microstructure of the zirconia hollow sphere ultra-high temperature furnace lining material prepared in this embodiment is shown; wherein, Figure a is the microstructure of the material after sintering, and Figure b is a further magnified microstructure.

[0049] Example 2

[0050] This embodiment discloses a zirconia hollow sphere ultra-high temperature furnace lining material, comprising 60 parts of zirconia hollow sphere aggregate, 4 parts of zirconia powder, 30 parts of alumina powder, and 4 parts of binder. The zirconia powder is magnesium-stabilized zirconia powder with a particle size ≤0.088mm and a ZrO2 content ≥90wt%. The alumina powder is plate-shaped corundum fine powder with a particle size ≤0.088mm and an Al2O3 content ≥90wt%.

[0051] This embodiment provides a method for preparing ultra-high temperature furnace lining material based on the aforementioned zirconia hollow sphere material, which specifically includes the following steps:

[0052] The preparation method of zirconia hollow spheres is as follows: First, 85 parts of zirconia powder, 25 parts of alumina powder, and 4 parts of yttrium oxide powder are placed in a three-phase electric arc furnace and heated to 2400℃ for 0.5h to obtain a molten mixture of zirconia, alumina, and yttrium oxide. Then, the molten mixture in the three-phase electric arc furnace is poured into a guide trough and sprayed into zirconia hollow spheres under a gas pressure of 1.0MPa. After the hollow spheres are cooled to room temperature, they are sieved through sieves of 5-3 mm, 3-1 mm, and 1-0.1 mm to obtain zirconia hollow sphere aggregates with particle sizes of 5-3 mm, 3-1 mm, and 1-0.1 mm, respectively.

[0053] The preparation method of zirconia hollow sphere ultra-high temperature furnace lining material is as follows: First, 60 parts of zirconia hollow sphere aggregate, 4 parts of zirconia powder, and 30 parts of alumina powder are mixed evenly, and then 4 parts of polyethylene glycol solution with an organic matter concentration of 8wt% are added. After stirring evenly, the mixture is pressed into a mixed compact under a molding pressure of 50MPa. The mixed compact is then subjected to high-temperature heat treatment at 1650℃ for 3 hours to obtain zirconia hollow sphere ultra-high temperature furnace lining material.

[0054] The particle size distribution of the hollow zirconia spheres in the ultra-high temperature liner material is as follows: 45 wt% of the hollow spheres have a particle size of 3–5 mm, 35 wt% have a particle size of 1–3 mm, and 20 wt% have a particle size of 0.1–1 mm. The porosity of the hollow zirconia spheres is ≥90%, and the wall thickness is 0.2 mm. The microstructure of the hollow zirconia spheres prepared in this embodiment is characterized by columnar zirconia grains randomly interspersed within alumina grains, with the alumina grain size being 500 nm and the zirconia grain size being 50 nm.

[0055] The zirconia hollow sphere ultra-high temperature liner material prepared in this embodiment has a porosity of 20%, a compressive strength of 75 MPa, a flexural strength of 8 MPa, a high-temperature flexural strength of 6.5 MPa at 1400℃, a thermal conductivity range of 0.8 W / m·K, a maximum operating temperature of 2100℃, and a compression creep of 0.03% under the conditions of 1400℃, 100 MPa, and 600 min.

[0056] Example 3

[0057] This embodiment discloses a zirconia hollow sphere ultra-high temperature furnace lining material, comprising 68 parts of zirconia hollow sphere aggregate, 12 parts of zirconia powder, 21 parts of alumina powder, and 3 parts of binder. The zirconia powder is yttrium-stabilized zirconia powder with a particle size ≤0.088mm and a ZrO2 content ≥90wt%. The alumina powder is plate-shaped corundum fine powder with a particle size ≤0.088mm and an Al2O3 content ≥90wt%.

[0058] This embodiment provides a method for preparing ultra-high temperature furnace lining material based on the aforementioned zirconia hollow sphere material, which specifically includes the following steps:

[0059] The preparation method of zirconia hollow spheres is as follows: First, 90 parts of zirconia powder, 15 parts of alumina powder, and 4 parts of yttrium oxide powder are placed in a three-phase electric arc furnace and heated to 2400℃ for 0.5h to obtain a molten mixture of zirconia, alumina, and yttrium oxide. Then, the molten mixture in the three-phase electric arc furnace is poured into a guide trough and sprayed into zirconia hollow spheres under a pressure of 0.8MPa. After the hollow spheres are cooled to room temperature, they are sieved through sieves of 5-3 mm, 3-1 mm, and 1-0.1 mm to obtain zirconia hollow sphere aggregates with particle sizes of 5-3 mm, 3-1 mm, and 1-0.1 mm, respectively.

[0060] The preparation method of zirconia hollow sphere ultra-high temperature furnace lining material is as follows: First, 68 parts of zirconia hollow sphere aggregate, 12 parts of zirconia powder, and 21 parts of alumina powder are mixed evenly, and then 3 parts of carboxymethyl cellulose solution with an organic matter concentration of 10wt% are added. After stirring evenly, the mixture is pressed into a mixed compact under a molding pressure of 75MPa. The mixed compact is then subjected to high-temperature heat treatment at 1650℃ for 3 hours to obtain zirconia hollow sphere ultra-high temperature furnace lining material.

[0061] The particle size distribution of the hollow zirconia spheres in the ultra-high temperature liner material is as follows: 40 wt% of the hollow spheres have a particle size of 3-5 mm, 40 wt% have a particle size of 1-3 mm, and 20 wt% have a particle size of 0.1-1 mm; the porosity of the hollow zirconia spheres is ≥80%, and the wall thickness of the hollow spheres is 0.5 mm. The microstructure of the hollow zirconia spheres prepared in this embodiment is characterized by columnar zirconia grains randomly interspersed within alumina grains, with the alumina grain size being 2500 nm and the zirconia grain size being 250 nm.

[0062] The zirconia hollow sphere ultra-high temperature liner material prepared in this embodiment has a porosity of 25%, a compressive strength of 75 MPa, a flexural strength of 10 MPa, a high-temperature flexural strength of 7.0 MPa at 1400℃, a thermal conductivity range of 1.0 W / m·K, a maximum operating temperature of 2200℃, and a compression creep of 0.02% under the conditions of 1400℃, 100 MPa, and 600 min.

[0063] Comparative Example 1

[0064] Comparative Example 1 provides an alumina hollow sphere ultra-high temperature furnace lining material, which comprises 68 parts of alumina hollow sphere aggregate, 33 parts of alumina powder, and 4 parts of binder.

[0065] The preparation method of this alumina hollow sphere ultra-high temperature furnace lining material specifically includes the following steps:

[0066] The preparation method of alumina hollow spheres is as follows: First, 100 parts of alumina powder are heated in a three-phase electric arc furnace at a temperature of 2200℃ for 0.5h to obtain molten alumina liquid; then, the mixed molten liquid in the three-phase electric arc furnace is poured into a guide trough and sprayed into alumina hollow spheres under a gas pressure of 0.8MPa; after the hollow spheres are cooled to room temperature, they are sieved through sieves of 5-3mm, 3-1mm, and 1-0.1mm to obtain alumina hollow sphere aggregates with particle sizes of 5-3mm, 3-1mm, and 1-0.1mm, respectively.

[0067] The preparation method of alumina hollow sphere ultra-high temperature furnace lining material is as follows: First, 68 parts of alumina hollow spheres and 33 parts of alumina powder are mixed evenly, and then 4 parts of polyvinyl alcohol solution of the raw materials are added. After stirring evenly, the mixture is pressed into a mixed compact under a molding pressure of 75 MPa. The mixed compact is then subjected to high temperature heat treatment at 1650℃ for 3 hours to obtain alumina hollow sphere ultra-high temperature furnace lining material.

[0068] The microstructure of the prepared alumina hollow spheres consists of dense alumina grains randomly arranged, with a grain size of 5000 nm. The particle size distribution of the hollow spheres in the ultra-high temperature liner material is as follows: 40 wt% of the hollow spheres have a particle size of 3-5 mm, 40 wt% have a particle size of 1-3 mm, and 20 wt% have a particle size of 0.1-1 mm. The porosity of the zirconium oxide hollow spheres is ≥80%, and the wall thickness of the hollow spheres is 0.7 mm.

[0069] The prepared zirconia hollow sphere ultra-high temperature liner material has a porosity of 25%, a compressive strength of 45 MPa, a flexural strength of 4 MPa, a high-temperature flexural strength of 3.0 MPa at 1400℃, a thermal conductivity range of 1.5 W / m·K, a maximum operating temperature of 1750℃, and a compression creep of 0.05% under the conditions of 1400℃, 100 MPa, and 600 min.

[0070] A comparison of Examples 1-3 and Comparative Example 1 revealed that the introduction of zirconia-alumina hollow spheres can significantly improve the mechanical properties, thermal shock stability, and thermal insulation performance of hollow sphere bricks, while also optimizing and improving the maximum service temperature of the material.

[0071] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A zirconia hollow sphere ultra-high temperature furnace lining material, characterized in that, It is made from the following raw materials in parts by weight: 60-75 parts zirconia hollow sphere aggregate, 4-18 parts zirconia powder, 12-30 parts alumina powder, and 2-5 parts binder; wherein: The zirconia powder is one of calcium-stabilized zirconia, magnesium-stabilized zirconia, and yttrium-stabilized zirconia, with a particle size ≤0.088mm and a ZrO2 content ≥90wt%. The alumina powder is a plate-shaped corundum fine powder with a particle size ≤0.088mm and an Al2O3 content ≥90wt%. The zirconia hollow sphere aggregate comprises the following components by weight: 85-95 parts zirconia powder, 5-25 parts alumina powder, and 3-5 parts yttrium oxide powder; The adhesive is an aqueous solution containing 5-10 wt% organic matter, which is selected from at least one of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, carrageenan, and starch. The microstructure of the zirconia hollow sphere aggregate is a eutectic structure in which elongated or columnar zirconia grains are randomly interspersed among alumina grains. The zirconia hollow sphere ultra-high temperature furnace lining material exhibits a compression creep of 0.01–0.03% under conditions of 1400℃, 100MPa, and 600min.

2. The zirconia hollow sphere ultra-high temperature furnace lining material as described in claim 1, characterized in that, The components of the zirconium oxide hollow sphere aggregate are as follows: zirconium oxide powder has a particle size ≤10μm and a purity of ZrO2 ≥99wt%; alumina powder has a particle size ≤10μm and a purity of Al2O3 ≥99wt%; and yttrium oxide powder has a particle size ≤10μm and a purity of Y2O3 ≥99wt%.

3. The zirconia hollow sphere ultra-high temperature furnace lining material as described in claim 1, characterized in that, The particle size distribution of the zirconia hollow sphere aggregate satisfies the following: hollow spheres with a particle size of 3-5 mm account for 40-50 wt% of the total weight of the hollow sphere aggregate, hollow spheres with a particle size of 1-3 mm account for 25-40 wt% of the total weight of the hollow sphere aggregate, and hollow spheres with a particle size of 0.1-1 mm account for 10-25 wt% of the total weight of the hollow sphere aggregate.

4. The zirconia hollow sphere ultra-high temperature furnace lining material as described in claim 1, characterized in that, The zirconia hollow sphere aggregate has a porosity of ≥70% and a wall thickness of 0.1–0.8 mm.

5. The zirconia hollow sphere ultra-high temperature furnace lining material as described in claim 1, characterized in that, In the eutectic structure, the alumina grain size is 500–5000 nm, and the zirconium oxide grain size is 50–2000 nm.

6. The zirconia hollow sphere ultra-high temperature furnace lining material as described in claim 1, characterized in that, The zirconia hollow sphere ultra-high temperature furnace lining material meets the following performance indicators: porosity of 20-30%, compressive strength of 70-100 MPa, flexural strength of 8-12 MPa, high-temperature flexural strength at 1400℃ of 6-8 MPa, thermal conductivity range of 0.8-1.6 W / m·K, and maximum operating temperature of 2000-2300℃.

7. A method for preparing an ultra-high temperature furnace lining material as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Alumina powder, zirconium oxide powder, and yttrium oxide powder are added to a three-phase electric arc furnace in proportion and heated to melt. The molten solution is then sprayed to form hollow spheres, cooled, and sieved to obtain zirconium oxide hollow sphere aggregate with a eutectic structure in which long strips or columnar zirconium oxide grains are randomly interspersed in alumina grains. S2. Mix 60-75 parts of the zirconia hollow sphere aggregate obtained in step S1 with 4-18 parts of zirconia powder, 12-30 parts of alumina powder, and 2-5 parts of binder evenly, press into shape, dry and fire to obtain zirconia hollow sphere ultra-high temperature furnace lining material.

8. The preparation method according to claim 7, characterized in that: In step S1, during the melt spraying process, the melt temperature is 2200-2500℃ and the spraying pressure is 0.6-1.0MPa.

9. The preparation method according to claim 7, characterized in that: In step S1, after the hollow spheres have cooled to room temperature, they are sieved through sieves with diameters of 3-5 mm, 1-3 mm, and 0.1-1 mm to obtain zirconium oxide hollow sphere aggregates with particle sizes of 3-5 mm, 1-3 mm, and 0.1-1 mm, respectively.

10. The preparation method according to claim 7, characterized in that: In step S2, the molding pressure is 50-100 MPa, the drying temperature is 80-110℃, the drying time is 24-36 h, the firing temperature is 1600-1800℃, and the firing time is 3-6 h.

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