High thermal shock resistance gradient function refractory concrete material and method for manufacturing the same

Abstract

The application provides a high thermal shock resistance gradient functional refractory concrete material and a preparation method thereof. The application constructs a three-layer gradient structure of a working layer, a transition layer and a heat insulation layer, and accurately controls the composition, thermophysical properties and thickness ratio of each layer, so that the thermal stress is released step by step between the layers, stress concentration is avoided, and the thermal shock resistance of the material is significantly improved. The three layers form a composition interdiffusion interface layer during the sintering process, further enhancing the interlayer bonding strength and avoiding delamination. The synergistic effect makes the thermal shock resistance of the material system of the application under the condition of 1100 DEG C water cooling reach more than 30 times, which is much better than the 8-12 times of the traditional homogeneous refractory concrete.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, specifically relating to a high thermal shock gradient functional refractory concrete material and its preparation method. Background Technology

[0002] Refractory concrete, as an important monolithic refractory material, is widely used in high-temperature industries such as metallurgy, building materials, and chemicals due to its advantages such as convenient construction, good integrity, and low production cost. However, in actual service, refractory concrete is frequently subjected to drastic temperature fluctuations (such as ladle turnover and kiln start-up and shutdown), leading to thermal stress within the material. Because traditional refractory concrete has a homogeneous structure, its thermal conductivity, coefficient of thermal expansion, and other thermophysical properties are uniformly distributed in space, making it difficult to effectively release thermal stress. This easily leads to stress concentration within the material, causing crack initiation and propagation, ultimately resulting in spalling or even structural failure. Therefore, improving the thermal shock resistance of refractory concrete has long been a core technical challenge in this field.

[0003] To address the aforementioned problems, existing technologies mainly focus on the following aspects: First, adding fiber-reinforcing components, such as steel fibers and ceramic fibers, to inhibit crack propagation through the bridging effect of fibers; second, introducing microcrack structures or phase change materials to alleviate thermal stress through microcrack deflection or phase change heat absorption; and third, optimizing aggregate gradation and matrix composition to improve the fracture toughness of the material. However, these methods all have significant limitations: fibers are prone to oxidation or sintering embrittlement at high temperatures (>1000℃), losing their toughening effect; microcrack structures reduce the strength and erosion resistance of the material; and the performance improvement potential of a single material is limited, making it difficult to simultaneously meet the multiple functional requirements of high fire resistance in the working layer, stress buffering in the intermediate layer, and low thermal conductivity in the insulation layer. More importantly, no existing technology has yet found a systematic solution to the thermal shock resistance problem of refractory concrete by constructing a multi-layer structure with a gradient distribution of thermophysical properties.

[0004] Therefore, how to achieve a controllable gradient distribution of thermal conductivity, coefficient of thermal expansion and thermal shock resistance parameters in the thickness direction of the material while maintaining the overall structural stability of refractory concrete, thereby significantly improving its thermal shock resistance and service life, is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides a high thermal shock resistance gradient functional refractory concrete material system. By constructing a three-layer gradient structure of a working layer, a transition layer, and a thermal insulation layer, and precisely controlling the composition, thermophysical properties, and thickness ratio of each layer, thermal stress is released stepwise between layers, avoiding stress concentration and significantly improving the thermal shock resistance of the material.

[0006] The present invention also provides an integrated layered casting preparation method for the above-mentioned material system. This method does not require expensive equipment and complex process control, can achieve gradual transition of interlayer components and strong bonding of interfaces, has low production cost, and is easy to industrialize.

[0007] A first aspect of the present invention provides a high thermal shock resistance gradient functional refractory concrete material, comprising a working layer, a transition layer and an insulation layer arranged sequentially, wherein the thermal conductivity, thermal expansion coefficient and thermal shock resistance parameters of the working layer, the transition layer and the insulation layer are gradient distributed. The working layer comprises corundum, silicon carbide, and antioxidants; The transition layer comprises corundum, mullite, and zircon; The insulation layer comprises lightweight mullite, hollow alumina spheres, and silica powder; The thickness ratio of the working layer, the transition layer and the insulation layer is 1:(0.5~1):(1~2).

[0008] One of the technical solutions of the present invention concerning high thermal shock resistant gradient functional refractory concrete materials has at least the following beneficial effects: By setting three structural layers with different compositions and functions, and ensuring their thermophysical properties are distributed in a gradient, thermal stress gradually decreases as it is transferred from the working layer to the insulation layer, avoiding sudden thermal shock damage caused by thermal stress concentration in traditional homogeneous materials. The corundum and silicon carbide in the working layer provide excellent high-temperature strength and corrosion resistance, while the antioxidant prevents high-temperature oxidation of the silicon carbide. The mullite and zircon in the transition layer have good thermal shock stability and moderate thermal conductivity, acting as stress buffers. The lightweight mullite and alumina hollow spheres in the insulation layer impart low thermal conductivity to the material, reducing heat loss. Simultaneously, the three layers form a component interdiffusion interface layer during firing, further enhancing the interlayer bonding strength and preventing delamination. This synergistic effect enables the material system of this invention to withstand more than 30 thermal shock cycles under water-cooled conditions at 1100℃, far exceeding the 8-12 cycles of traditional homogeneous refractory concrete.

[0009] According to some embodiments of the present invention, the thickness ratio of the working layer, the transition layer and the heat insulation layer is any ratio in the range of 1:(0.5, 0.6, 0.7, 0.8, 0.9, 1):(1, 1.2, 1.4, 1.6, 1.8, 2), such as 1:0.7:1.5, or any sub-range ratio formed by the values ​​of any two, such as 1:(0.6~0.9):(1.2~1.8).

[0010] According to some embodiments of the present invention, the mass ratio of corundum, silicon carbide and antioxidant in the working layer is (60-75):(15-25):(1-3).

[0011] According to some embodiments of the present invention, the mass ratio of corundum, silicon carbide and antioxidant in the working layer is any one of (60, 63, 66, 69, 72, 75):(15, 17, 19, 21, 23, 25):(1, 1.5, 2, 2.5, 3), such as (68):(20):(2), or any sub-range ratio formed by the values ​​of any two, such as (65-72):(18-23):(1.5-2.5).

[0012] According to some embodiments of the present invention, the mass ratio of corundum, mullite and zircon in the transition layer is (40-60):(20-35):(5-15).

[0013] According to some embodiments of the present invention, the mass ratio of corundum, mullite and zircon in the transition layer is any one of (40, 44, 48, 52, 56, 60):(20, 23, 26, 29, 32, 35):(5, 7, 9, 11, 13, 15), such as 50:28:10, or any range of the values ​​of any two, such as (45-55):(22-32):(7-13).

[0014] According to some embodiments of the present invention, the mass ratio of lightweight mullite, alumina hollow spheres and silica powder in the heat insulation layer is (30-50):(20-40):(5-15).

[0015] According to some embodiments of the present invention, the mass ratio of lightweight mullite, hollow alumina spheres and silica powder in the heat insulation layer is any one of (30, 34, 38, 42, 46, 50):(20, 24, 28, 32, 36, 40):(5, 7, 9, 11, 13, 15), such as 40:30:10, or any range of the two values, such as (35-45):(25-35):(7-13).

[0016] The optimization of the above mass ratio range is conducive to forming a smooth thermophysical property gradient, while ensuring the mechanical and high-temperature properties of each layer.

[0017] According to some embodiments of the present invention, the thermal conductivity of the working layer is 12 to 20 W / (m·K).

[0018] According to some embodiments of the present invention, the thermal conductivity of the working layer is any value among 12 W / (m·K), 13 W / (m·K), 14 W / (m·K), 15 W / (m·K), 16 W / (m·K), 17 W / (m·K), 18 W / (m·K), 19 W / (m·K), and 20 W / (m·K), such as 16 W / (m·K), or any range formed by both, such as 14 W / (m·K) to 18 W / (m·K).

[0019] According to some embodiments of the present invention, the thermal conductivity of the transition layer is 5 to 10 W / (m·K).

[0020] According to some embodiments of the present invention, the thermal conductivity of the transition layer is any value among 5 W / (m·K), 6 W / (m·K), 7 W / (m·K), 8 W / (m·K), 9 W / (m·K), and 10 W / (m·K), such as 7 W / (m·K), or a range of any two, such as 6 W / (m·K) to 9 W / (m·K).

[0021] According to some embodiments of the present invention, the thermal conductivity of the insulation layer is 0.5 to 2.5 W / (m·K).

[0022] According to some embodiments of the present invention, the thermal conductivity of the insulation layer is 0.5 W / (m²). K), 1.0W / (m K), 1.5W / (m K), 2.0W / (m K), 2.5W / (m Any value in K), such as 1.5W / (m K), or any range of values ​​formed by both, such as 1.0W / (m K)~2.0W / (m K).

[0023] According to some embodiments of the present invention, the ratio of thermal conductivity between adjacent layers does not exceed 9:1.

[0024] This thermal conductivity gradient design avoids interfacial thermal stress caused by excessive differences in the thermophysical properties of adjacent layers, ensuring the overall coordinated deformation of the multilayer structure under thermal shock.

[0025] According to some embodiments of the present invention, the working layer further includes an antioxidant, which is at least one of B4C, Si powder or metallic Al powder; the heat insulation layer further includes a pore-forming agent, which is polystyrene microspheres or organic fibers.

[0026] Antioxidants can effectively inhibit the high-temperature oxidation of silicon carbide during firing and use; pore-forming agents decompose and volatilize during firing, forming micron-sized pores in the insulation layer, further reducing thermal conductivity.

[0027] According to some embodiments of the present invention, a component interdiffusion interface layer is formed between the working layer and the transition layer, and between the transition layer and the heat insulation layer, respectively. The thickness of the component interdiffusion interface layer is 0.1 to 1 mm, and the component interdiffusion interface layer contains a gradually distributed corundum, mullite and zircon phases.

[0028] The interdiffusion interface layer is naturally formed during the firing process using the integrated layered casting process of this invention. It eliminates the sharp interfaces commonly found in traditional multilayer materials, achieving a continuous transition in composition, structure, and properties. This is one of the key points for achieving excellent thermal shock resistance in this invention.

[0029] A second aspect of the present invention provides a method for preparing a high thermal shock gradient functional refractory concrete material according to the first aspect of the present invention, comprising the following steps: S1: Weigh the raw materials for each layer according to the formula of the working layer, transition layer and insulation layer, and dry mix them evenly to obtain the working layer mixture, transition layer mixture and insulation layer mixture; S2: First pour the heat insulation layer mixture into the bottom of the mold and then vibrate it to flatten it; S3: Before the initial setting of the insulation layer mixture, pour the transition layer mixture onto the insulation layer and vibrate and flatten it again. S4: Before the initial setting of the transition layer mixture, pour the working layer mixture onto the transition layer and vibrate it again; S5: Overall curing, demolding, drying, and firing to obtain the material system described above; Among them, the time interval between the pouring of two adjacent layers in S2 to S4 is ≤30 minutes.

[0030] The preparation method of this invention adopts an integrated process of layered casting, synchronous vibration, and overall curing, which does not require complex equipment and control and is easy to operate. By continuously casting before initial setting, vibration is used to cause partial mixing and interdiffusion of components between layers, forming a natural component gradient interface layer after firing, avoiding the defect of weak interface bonding in the traditional layered preparation of multi-layer materials. The method has mild reaction conditions, uses commercially available conventional refractory materials as raw materials, has low production costs, and is suitable for large-scale industrial production.

[0031] According to some embodiments of the present invention, in step S5, the firing temperature is 1100-1300°C, the heating rate is 3-8°C / min, the holding time is 2-5 hours, and the firing atmosphere is air.

[0032] The above firing process ensures sufficient sintering and interfacial diffusion between layers, while avoiding excessive oxidation of silicon carbide and antioxidants.

[0033] According to some embodiments of the present invention, in steps S2 to S4, the vibration time after each pouring is 30 to 90 seconds, and the vibration frequency is 50 to 100 Hz.

[0034] Appropriate vibration parameters are beneficial for the compaction of the mixture and the proper mixing of interlayer components.

[0035] According to some embodiments of the present invention, in step S5, the curing conditions are: curing at a temperature of 20-30°C and a relative humidity of ≥90% for 24-48 hours; the drying conditions are: drying at 110°C for 12-24 hours.

[0036] The above-mentioned curing and drying procedures ensure that the hydration reaction of the cement binder proceeds fully and that the green body is completely demolded.

[0037] According to some embodiments of the present invention, the method further includes applying unidirectional pressure to the overall structure before firing, with a pressure of 0.5 to 2 MPa and a holding time of 10 to 30 minutes, to enhance the interlayer bonding strength.

[0038] This pressurization step can further improve the interlayer mechanical interlocking and diffusion, making it suitable for applications with higher requirements for thermal shock resistance. Detailed Implementation

[0039] The following will describe the concept and technical effects of the present invention clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0040] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0041] Unless otherwise specified, "room temperature" in this invention means 25℃±5℃.

[0042] Unless otherwise specified, "about" in this invention means that the allowable error is within ±2%.

[0043] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0044] It should be noted that, according to the conventions of the refractory castable industry, the matrix components are aggregate, powder, functional additives, and cement, with a total proportion of 100wt%. Other water-reducing agents, water, and pore-forming agents are added as admixtures and are not included in the matrix proportion.

[0045] Example 1 A high thermal shock gradient functional refractory concrete material is prepared by weighing raw materials according to the formulas of the working layer, transition layer and insulation layer. The overall thickness is designed to be 150 mm, and the thickness ratio of each layer is 1:0.8:1.5, that is, the working layer is about 45 mm, the transition layer is about 37 mm and the insulation layer is about 68 mm.

[0046] Working layer formula (by weight): 55wt% corundum aggregate (3-1mm), 15wt% fine corundum powder (<0.088mm), 20wt% fine silicon carbide powder (<0.045mm), 2wt% B4C antioxidant, 8wt% calcium aluminate cement (CA-70), 0.5wt% added polycarboxylate superplasticizer, and 4.5wt% added water.

[0047] Transition layer formula (by weight): 48wt% corundum aggregate (3-1mm), 30wt% mullite fine powder (<0.088mm), 12wt% zircon fine powder (<0.074mm), 10wt% calcium aluminate cement (CA-70), and 8.0wt% added water.

[0048] Insulation layer formula (by weight): 48wt% lightweight mullite aggregate (3-0.5mm), 30wt% alumina hollow spheres (0.5-0.2mm), 10wt% silica fume (SiO2≥92%, <0.045mm), 12wt% calcium aluminate cement (CA-70), 5wt% added polystyrene microspheres (0.2-0.5mm particle size), and 3.0wt% added water.

[0049] Each layer of raw materials was dry-mixed for 3 minutes, then water was added and stirred for 2 minutes. The insulation layer mixture was first poured into the mold and vibrated for 60 seconds (vibration frequency 80Hz); after standing for 8 minutes, the transition layer mixture was poured and vibrated for 60 seconds; after standing for 8 minutes, the working layer mixture was poured and vibrated for 90 seconds. The entire mixture was cured for 24 hours at 25℃ and relative humidity ≥90%, then demolded and dried at 110℃ for 24 hours. The temperature was then increased to 1250℃ at a rate of 5℃ / min, held for 3 hours, and then cooled to room temperature in the furnace to obtain the sample of Example 1.

[0050] It should be noted that in the embodiments, "3-1mm" in corundum aggregate (3-1mm) indicates the particle size range of the aggregate, that is, the particle size is between 1 mm and 3 mm. This representation method is very common in industries such as refractory materials, concrete, and ceramics, and is used to describe the particle size distribution of aggregates or powders.

[0051] Example 2 A high thermal shock resistant gradient functional refractory concrete material is designed with an overall thickness of 120mm and a layer thickness ratio of 1:0.6:1.2, that is, the working layer is about 43mm, the transition layer is about 26mm, and the insulation layer is about 51mm.

[0052] Working layer formula (by weight): 60wt% corundum aggregate (3-1mm), 11.5wt% corundum fine powder (<0.088mm), 18wt% silicon carbide fine powder (<0.045mm), 1.5wt% metallic Al powder antioxidant, 9wt% calcium aluminate cement (CA-70), 0.6wt% added polycarboxylate superplasticizer, and 2.9wt% added water.

[0053] Transition layer formula (by weight): 45wt% corundum aggregate (3-1mm), 28wt% mullite fine powder (<0.088mm), 10wt% zircon fine powder (<0.074mm), 9wt% calcium aluminate cement (CA-70), and 8wt% added water.

[0054] Insulation layer formula (by weight): 45wt% lightweight mullite aggregate (3-0.5mm), 25wt% alumina hollow spheres (0.5-0.2mm), 12wt% silica fume, 10wt% calcium aluminate cement (CA-70), 3wt% added organic fiber (polypropylene fiber, 3mm in length), and 5wt% added water.

[0055] The preparation process is the same as in Example 1, except that: the interval between two adjacent pours is 10 minutes; the vibration frequency is 60 Hz, and each vibration lasts for 50 seconds; the curing time is 48 hours; the firing temperature is 1200℃, the heating rate is 4℃ / min, the holding time is 4 hours, and the atmosphere is air. This yields the sample of Example 2.

[0056] Example 3 A high thermal shock gradient functional refractory concrete material is designed with an overall thickness of 180mm and a layer thickness ratio of 1:1:2, namely, a working layer of about 45mm, a transition layer of about 45mm, and a thermal insulation layer of about 90mm.

[0057] Working layer formula (by weight): 50wt% corundum aggregate (3-1mm), 18wt% fine corundum powder (<0.088mm), 22wt% fine silicon carbide powder (<0.045mm), 3wt% Si powder antioxidant, 7wt% calcium aluminate cement (CA-70), 0.4wt% added polycarboxylate superplasticizer, and 5.6wt% added water.

[0058] Transition layer formula (by weight): 50wt% corundum aggregate (3-1mm), 25wt% mullite fine powder (<0.088mm), 8wt% zircon fine powder (<0.074mm), 10wt% calcium aluminate cement (CA-70), and 7wt% added water.

[0059] Insulation layer formula (by weight): 35wt% lightweight mullite aggregate (3-0.5mm), 35wt% alumina hollow spheres (0.5-0.2mm), 8wt% silica fume, 14wt% calcium aluminate cement (CA-70), 6wt% added polystyrene microspheres, and 2wt% added water.

[0060] The preparation process was the same as in Example 1, except that: the interval between casting two adjacent layers was 15 minutes; the vibration frequency was 70 Hz, and each vibration lasted 80 seconds; a unidirectional pressure of 1.0 MPa was applied to the entire sample before firing (low pressure only optimizes the microporosity within the green body and has limited effect on improving the interlayer interface bonding), and the pressure was held for 20 minutes; the firing temperature was 1280℃, the heating rate was 6℃ / min, and the holding time was 2.5 hours. This yielded the sample of Example 3.

[0061] It should be noted that in Examples 1 to 3, the initial setting time of each castable is >30 min, so an 8-15 min interval meets the construction requirements before initial setting.

[0062] Comparative Example 1 Traditional homogeneous refractory concrete was used as a control.

[0063] Formula (same as the working layer composition in Example 1): 55wt% corundum aggregate (3-1mm), 10wt% corundum fine powder (<0.088mm), 20wt% silicon carbide fine powder (<0.045mm), 2wt% B4C antioxidant, 8wt% calcium aluminate cement (CA-70), 0.5wt% added polycarboxylate superplasticizer, and 4.5wt% added water.

[0064] Preparation method: Mix all raw materials together dry for 3 minutes, add water and stir for 2 minutes, then pour the mixture into a mold and vibrate for 90 seconds. The curing, demolding, drying, and firing conditions are exactly the same as in Example 1 (1250℃ for 3 hours). A homogeneous sample with a thickness of 150 mm is obtained.

[0065] Comparative Example 2 Traditional double-layer fire-resistant concrete has no transition layer.

[0066] formula: Working layer: Same as the working layer formula in Example 1.

[0067] Insulation layer: Same as the insulation layer formula in Example 1.

[0068] No transition layer.

[0069] Preparation method: Materials were prepared separately for each of the two layers. First, the insulation layer was poured, vibrated for 60 seconds, and allowed to stand for 8 minutes before pouring the working layer and vibrating for 90 seconds. Curing, demolding, drying, and firing conditions were exactly the same as in Example 1 (1250℃ for 3 hours). A double-layered sample was obtained, with the working layer and insulation layer having thicknesses of approximately 75 mm and approximately 75 mm respectively (total thickness 150 mm).

[0070] Performance testing methods and results Test method: Bulk density: Tested according to GB / T2997-2015.

[0071] Apparent porosity: Tested according to GB / T2997-2015.

[0072] Pressure resistance at room temperature: tested according to GB / T5072-2023.

[0073] Thermal conductivity: Tested according to GB / T17911-2018 (hot wire method) at a temperature of 1000℃.

[0074] Thermal shock resistance: According to GB / T30873-2014 (water cooling method), the sample is heated to 1100℃ and held for 30 minutes, then immersed in flowing water at 15-25℃ to cool. This process is repeated until visible cracks appear on the sample surface or the mass loss rate is ≥20%. The number of cycles is recorded.

[0075] Interlaminar shear strength: Tested according to JC / T2630-2021 to characterize interlaminar bond strength.

[0076] High-temperature flexural strength: Tested at 1200℃ according to GB / T3002-2017.

[0077] Coefficient of thermal expansion: According to GB / T7320-2018, the test temperature range is room temperature to 1200℃.

[0078] Test Results As shown in Table 1.

[0079] Table 1

[0080] As can be seen from Table 1: Regarding thermal shock resistance, the three embodiments showed significantly better thermal shock resistance (30-35 cycles) than Comparative Example 1 (10 cycles) and Comparative Example 2 (15 cycles). Example 3 performed best (35 cycles), which is related to its thicker insulation layer design, lower interlayer thermal conductivity ratio, and pressurized firing process. This demonstrates that the gradient functional structure of the present invention can effectively alleviate thermal stress concentration.

[0081] Regarding interlayer bonding strength, the interlayer shear strength (4.2~5.2MPa) of Examples 1-3 is much higher than that of Comparative Example 2 (2.1MPa), indicating that the presence of the transition layer and the component interdiffusion interface layer formed by continuous casting before initial setting significantly enhance the integrity of the multilayer structure and prevent interface peeling.

[0082] Regarding high-temperature strength, the high-temperature flexural strength of the embodiment (11.8~13.2MPa) is higher than that of Comparative Example 1 (10.2MPa) and Comparative Example 2 (8.5MPa), indicating that the gradient structure does not sacrifice high-temperature mechanical properties, but instead reduces microcrack damage due to thermal stress relief.

[0083] The room temperature pressure resistance of Comparative Example 1 is greater than that of the three-layer sample, but the high temperature flexural strength is lower. This is because the homogeneous material is prone to internal through-cracks due to thermal shock, resulting in significant deterioration of high temperature load-bearing capacity.

[0084] Regarding failure modes, the embodiment exhibits a "slow, layer-by-layer peeling" failure mode, meaning that during thermal shock, microcracks first appear in the working layer but are blocked by the transition layer, and the structure still maintains its integrity. This is a typical characteristic of highly thermally shock resistant materials. In contrast, Comparative Example 1 exhibits "overall brittle fracture," and Comparative Example 2 exhibits "interfacial delamination," both of which are unfavorable for practical applications.

[0085] The above results fully demonstrate that the high thermal shock gradient functional refractory concrete material system of the present invention has achieved significant technical progress compared with the prior art, and has outstanding substantive features and significant advancements.

[0086] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high thermal shock gradient functional refractory concrete material, characterized in that, It includes a working layer, a transition layer and a thermal insulation layer arranged sequentially, and the thermal conductivity, thermal expansion coefficient and thermal shock resistance parameters of the working layer and the transition layer and the thermal insulation layer are distributed in a gradient. The working layer comprises corundum, silicon carbide, and antioxidants; The transition layer comprises corundum, mullite, and zircon; The insulation layer comprises lightweight mullite, hollow alumina spheres, and silica powder; The thickness ratio of the working layer, the transition layer and the insulation layer is 1:(0.5~1):(1~2).

2. The high thermal shock gradient functional refractory concrete material according to claim 1, characterized in that, The working layer contains corundum, silicon carbide, and antioxidant in a mass ratio of (60–75):(15–25):(1–3); and / or the transition layer contains corundum, mullite, and zircon in a mass ratio of (40–60):(20–35):(5–15); and / or the insulation layer contains lightweight mullite, hollow alumina spheres, and silica fume in a mass ratio of (30–50):(20–40):(5–15); and / or the working layer, transition layer, and insulation layer also contain calcium aluminate cement; based on 100 wt% of the total mass of the matrix raw materials of each layer, the amount of calcium aluminate cement added to the working layer is 7–10 wt%, the amount added to the transition layer is 8–11 wt%, and the amount added to the insulation layer is 9–15 wt%.

3. The high thermal shock resistant gradient functional refractory concrete material according to claim 1, characterized in that, The thermal conductivity of the working layer is 12-20 W / (m·K), the thermal conductivity of the transition layer is 5-10 W / (m·K), and the thermal conductivity of the insulation layer is 0.5-2.5 W / (m·K); and the ratio of thermal conductivity between adjacent layers is ≤9:

1.

4. The high thermal shock gradient functional refractory concrete material according to claim 1, characterized in that, The working layer further includes an antioxidant, which is at least one of B4C, Si powder or metallic Al powder; and / or, the heat insulation layer further includes a pore-forming agent, which is polystyrene microspheres or organic fibers; and / or, the amount of the pore-forming agent added is 3 to 6 wt%.

5. The high thermal shock gradient functional refractory concrete material according to claim 1, characterized in that, A component interdiffusion interface layer is formed between the working layer and the transition layer, and between the transition layer and the insulation layer. The thickness of the component interdiffusion interface layer is 0.1-1 mm, and the component interdiffusion interface layer contains gradually distributed corundum, mullite and zircon phases.

6. A method for preparing high thermal shock gradient functional refractory concrete material as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Weigh the raw materials for each layer according to the formula of the working layer, transition layer and insulation layer, and dry mix them evenly to obtain the working layer mixture, transition layer mixture and insulation layer mixture; S2: First pour the heat insulation layer mixture into the bottom of the mold and then vibrate it to flatten it; S3: Before the initial setting of the insulation layer mixture, pour the transition layer mixture onto the insulation layer and vibrate and flatten it again. S4: Before the initial setting of the transition layer mixture, pour the working layer mixture onto the transition layer and vibrate it again; S5: Overall curing, demolding, drying, and firing to obtain the high thermal shock gradient functional refractory concrete material; Among them, the time interval between the pouring of two adjacent layers in S2 to S4 is ≤30 minutes.

7. The method according to claim 6, characterized in that, In step S5, the firing temperature is 1100-1300℃, the heating rate is 3-8℃ / min, the holding time is 2-5 hours, and the firing atmosphere is air.

8. The method according to claim 6, characterized in that, In steps S2 to S4, the vibration time after each pour is 30 to 90 seconds, and the vibration frequency is 50 to 100 Hz.

9. The method according to claim 6, characterized in that, In step S5, the curing conditions are: 20-30℃ and relative humidity ≥90% for 24-48 hours; the drying conditions are: 110℃ for 12-24 hours.

10. The method according to claim 6, characterized in that, The method also includes applying unidirectional pressure to the overall structure before firing, with a pressure of 0.5 to 2 MPa and a holding time of 10 to 30 minutes, to enhance the interlayer bonding strength.

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