A rotary kiln composite lining structure

Abstract

The application discloses a rotary kiln composite lining structure and belongs to the technical field of thermal equipment. The rotary kiln composite lining is designed by a structure of a working layer, a functional layer and an anchoring structure, integrates the concepts of mechanical reinforcement and energy-saving protection, and can realize good structural stability and heat insulation performance. Through efficient reflection of radiant heat by a reflection layer, cooperative heat conduction blocking of a heat preservation layer and a heat insulation layer, resistance to corrosion and stress buffering of a protection layer, and anti-abrasion and high-temperature corrosion resistance of the working layer, a hierarchical heat protection system is formed. In combination with a quasi-flexible connection system in the anchoring structure, the rotary kiln thermal expansion stress and shear stress in the rotating process can be reduced under the premise of ensuring the connection strength, and the overall stability of the structural layer is improved. The rotary kiln composite lining provided by the application has mechanical strength and heat insulation performance, can obtain a relatively long service life, and realizes efficient energy saving of the rotary kiln.

Description

Technical Field

[0001] This invention relates to the field of thermal equipment technology, specifically a composite lining structure for a rotary kiln. Background Technology

[0002] A rotary kiln is a key piece of equipment widely used in industrial production. Its main body is a cylindrical structure with a certain tilt angle. Through the continuous and slow rotation of the kiln body, the materials are fully mixed and contacted to carry out efficient reactions. It is widely used in many important fields such as cement calcination in the building materials industry, ore roasting in the metallurgical industry, raw material processing in the chemical industry, and high-temperature disposal of hazardous waste in the environmental protection industry.

[0003] During operation, the internal temperature of a rotary kiln can reach over 1300℃. Traditional insulated lining structures have physical limitations in their insulation performance, resulting in significant heat loss through conduction. This often causes the outer surface temperature of the kiln shell to exceed 250℃, leading to thermal pollution of the working environment, energy waste, and increased production energy consumption. Furthermore, under high-temperature conditions, the mechanical strength and structural stability of the lining are difficult to maintain effectively, making the lining structure prone to cracking and deformation, which significantly impacts the service life of the rotary kiln.

[0004] Therefore, in current research on thermal structures and materials, how to effectively improve the mechanical strength and structural stability of materials while maintaining low thermal conductivity, so that rotary kiln linings can have both long service life and high energy efficiency, has significant application value and research significance. Summary of the Invention

[0005] To address this issue, the present invention provides a composite lining structure for rotary kilns, aiming to resolve the core contradiction of traditional rotary kiln linings in achieving both "long service life" and "energy saving" under high-temperature conditions. While ensuring thermal insulation performance, it effectively improves the structural stability and mechanical strength of the rotary kiln lining.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A rotary kiln composite lining structure includes a working layer, a functional layer, and an anchoring structure, wherein the functional layer is located between the working layer and the inner wall of the rotary kiln cylinder; the functional layer is one or a combination of two or more of the following: a reflective layer, a heat insulation layer, a protective layer, and a thermal insulation layer.

[0008] The anchoring structure is provided at equal intervals along the axial and circumferential directions of the inner wall of the rotary kiln cylinder, and extends from the inner wall of the rotary kiln cylinder toward the interior of the rotary kiln through the functional layer and into the working layer.

[0009] The anchoring structure includes a fixing block and an anchoring hook installed on the fixing block. The fixing block is fixedly installed on the inner wall of the rotary kiln cylinder. The anchoring hook is flexibly fixed to the fixing block, so that the anchoring hook releases thermal expansion stress under high temperature conditions, thereby extending the service life of the anchoring hook and improving the stability of the lining structure.

[0010] The above technical solution integrates the concepts of mechanical reinforcement and energy-saving protection through the structural design of "working layer + functional layer + anchoring structure". It can achieve good structural stability and thermal insulation performance. At the same time, by setting the anchoring structure and setting the anchoring structure as a flexible fixed connection structure, it can not only ensure the connection strength between each structural layer and improve the integrity and stability of the inner lining structure layer, but also buffer and release the thermal expansion stress and rotational shear stress during use, thus extending the service life of the rotary kiln lining.

[0011] Furthermore, in the rotary kiln composite lining structure, the functional layer includes a reflective layer and a main functional layer. The main functional layer is one or a combination of a protective layer and a heat insulation layer. The reflective layer is a nano-ceramic heat-insulating coating used to reduce heat loss from the rotary kiln. The reflective layer is in close contact with the inner wall of the rotary kiln cylinder. The protective layer is one or a combination of two or more of the following: hydrophobic aluminosilicate fiber board, hydrophobic aluminosilicate fiber felt, hydrophobic aluminosilicate fiber blanket, and hydrophobic aluminosilicate fiber paper. The heat insulation layer is one or a combination of two or more of the following: high-temperature resistant lightweight spray coating, high-temperature resistant lightweight coating, high-temperature resistant medium-grade spray coating, and high-temperature resistant medium-grade coating. The heat insulation layer is in direct contact with the working layer.

[0012] In the above technical solution, the reflective layer is the layer closest to the inner wall of the cylinder. Its core function is to reflect thermal radiation. By spraying or brushing a layer of nano-ceramic heat-insulating coating, a large amount of radiant heat inside the kiln can be directly reflected back, reducing the transfer of heat to the cylinder steel plate from the first barrier. The protective layer is a hydrophobic aluminosilicate fiber product. Its hydrophobic treatment can effectively resist the penetration of corrosive substances, protecting the subsequent structural layers and cylinder. Its dense structure can also play a sealing role, preventing hot air and corrosive media from entering. At the same time, the fiber material has a certain degree of elasticity, which can buffer the stress caused by the different thermal expansion coefficients between the layers. The heat insulation layer is the second heat insulation barrier. It uses lightweight or medium-weight refractory materials to further reduce thermal conductivity while ensuring a certain structural strength. This layer can work together with the heat insulation layer and the reflective layer to control the temperature of the rotary kiln cylinder (kiln skin) at a low level, achieving a significant energy-saving effect. Through the multi-functional combination of the reflective layer's efficient reflection of radiant heat, the heat insulation layer's blocking of heat conduction, the protective layer's resistance to corrosion and buffering of stress, and the working layer's wear resistance and high-temperature erosion resistance, a multi-layered thermal protection system is formed. This multi-layered thermal protection system provides comprehensive protection from multiple dimensions, including heat radiation reflection, heat conduction barrier, corrosion protection, and direct resistance to the impact of high-temperature materials. It can significantly reduce heat loss to the outside of the kiln and achieve high efficiency and energy saving.

[0013] Furthermore, in the rotary kiln composite lining structure, the functional layer is one or a combination of a protective layer and a heat insulation layer. The protective layer is one or a combination of more than two of the following: hydrophobic aluminum silicate fiberboard, hydrophobic aluminum silicate fiber felt, hydrophobic aluminum silicate fiber blanket, and hydrophobic aluminum silicate fiber paper. The heat insulation layer is one or a combination of more than two of the following: high-temperature resistant lightweight spray coating, high-temperature resistant lightweight coating material, high-temperature resistant medium-grade spray coating, and high-temperature resistant medium-grade coating material.

[0014] In the above technical solution, the protective layer is a hydrophobic aluminosilicate fiber product. Its hydrophobic treatment can effectively resist the penetration of corrosive substances, protect the subsequent structural layers and cylinder, and its dense structure can also play a sealing role, preventing hot air and corrosive media from entering. At the same time, the fiber material has a certain elasticity, which can buffer the stress caused by the different coefficients of thermal expansion between the layers. The heat insulation layer can form a heat insulation barrier. It uses lightweight or medium-weight refractory materials to reduce heat conduction while ensuring a certain structural strength. It can work together with the reflective layer to control the temperature of the rotary kiln cylinder (kiln skin) at a low level, achieving a significant energy-saving effect.

[0015] Furthermore, the functional layer includes a thermal insulation layer and a protective layer, with the protective layer in contact with the working layer. The thermal insulation layer is one or a combination of two of nano-insulation boards and aerogel felts, and the protective layer is one or a combination of more than two of hydrophobic aluminum silicate fiber boards, hydrophobic aluminum silicate fiber felts, hydrophobic aluminum silicate fiber blankets, and hydrophobic aluminum silicate fiber paper.

[0016] In the above scheme, the insulation layer is the main heat conduction barrier layer. The nano-insulation board or aerogel material used has an extremely low thermal conductivity, which can effectively inhibit heat penetration. The protective layer is a hydrophobic aluminum silicate fiber product. Because the protective layer has been waterproofed, it can block moisture from penetrating into the insulation layer and prevent excessive heat from being transferred to the insulation layer, ensuring that the insulation layer does not sinter or pulverize during use, and fully utilizing the thermal insulation effect of the nanomaterials. The hydrophobic treatment of the protective layer can effectively resist the penetration of corrosive substances, protecting the subsequent structural layers and cylinder. Its dense structure can also play a sealing role, preventing hot air and corrosive media from entering. In addition, the fiber material has a certain degree of elasticity, which can buffer the stress caused by the different coefficients of thermal expansion between the structural layers.

[0017] Furthermore, in the rotary kiln composite lining structure, from the inner wall of the rotary kiln cylinder towards the interior of the rotary kiln, a reflective layer, a heat insulation layer, a protective layer, a heat insulation layer, and a working layer are sequentially arranged; the reflective layer is a nano-ceramic heat-insulating coating with a thickness of 0.2-2mm; the heat insulation layer is one or a combination of two of nano-insulating boards and aerogel felt with a thickness of 5-40mm; the protective layer is one or a combination of more than two of hydrophobic aluminosilicate fiberboard, hydrophobic aluminosilicate fiber felt, hydrophobic aluminosilicate fiber blanket, and hydrophobic aluminosilicate fiber paper with a thickness of 1-50mm; the heat insulation layer is one or a combination of more than two of high-temperature resistant lightweight spray coating, high-temperature resistant lightweight coating material, high-temperature resistant medium-weight spray coating, and high-temperature resistant medium-weight coating material with a thickness of 30-100mm; and the working layer is one or a combination of more than two of refractory bricks, precast blocks, castables, ramming mixes, heavy pumped materials, and heavy spray coating with a thickness of 100-300mm.

[0018] In the above technical solution, the reflective layer is the layer closest to the inner wall of the cylinder. Its core function is to reflect heat radiation. By spraying or brushing a layer of nano-ceramic heat-insulating coating, a large amount of radiant heat inside the kiln can be directly reflected back, reducing the transfer of heat to the cylinder steel plate from the first barrier. The insulation layer is the main heat conduction barrier layer. The nano-insulation board or aerogel material used has an extremely low thermal conductivity, which can effectively inhibit heat penetration. The protective layer is a hydrophobic aluminum silicate fiber product. Its hydrophobic treatment can effectively resist the penetration of corrosive substances, protecting the subsequent structural layers and cylinder. Its dense structure can also play a sealing role, preventing hot air and corrosive media from entering. At the same time, the fiber... The refractory material has a certain degree of elasticity, which can buffer the stress caused by the different coefficients of thermal expansion between the layers. The insulation layer is the second thermal barrier, made of lightweight or medium-weight refractory materials. While ensuring a certain structural strength, it further reduces thermal conductivity. This layer can work together with the insulation layer and the reflective layer to control the temperature of the rotary kiln shell (kiln skin) at a low level, achieving significant energy-saving effects. The working layer is the layer that directly contacts high-temperature materials and flames. The materials of the working layer have high integrity, good high-temperature resistance and thermal shock resistance, and strong resistance to wear, atmosphere erosion and slag. It can withstand high-temperature erosion, slag erosion and atmosphere erosion, ensuring the service life of the lining. Through the efficient reflection of radiant heat by the reflective layer, the synergistic blocking of heat conduction by the insulation layer and the heat insulation layer, the corrosion resistance and stress buffering of the protective layer, and the wear resistance and high-temperature erosion resistance of the working layer, a complete and synergistic "reflection-blocking-protection-reblocking-working" layered thermal protection system is formed. This multi-layered thermal protection system provides comprehensive protection from multiple dimensions, including heat radiation reflection, heat conduction barrier, corrosion protection, and direct resistance to the impact of high-temperature materials. It can not only minimize the loss of heat to the outside of the kiln and achieve high efficiency and energy saving, but also effectively protect the integrity and stability of the inner lining structure under complex high-temperature conditions and improve the overall performance of the rotary kiln lining.

[0019] Furthermore, the fixing block is provided with a mounting through hole, and the anchor hook passes through the mounting through hole;

[0020] The anchoring hook includes a first anchoring arm, a second anchoring arm, and a transition connecting section connecting the first anchoring arm and the second anchoring arm. The anchoring hook is disposed in the mounting through hole through the transition connecting section.

[0021] Within the mounting through hole, the transition connecting section is locally fixedly connected to the hole wall, while the remaining area is a flexible space, so that a flexible fixed connection that can extend and swing slightly is formed between the anchor hook and the fixing block.

[0022] In the above technical solution, the flexible fixed connection between the anchor hook and the fixing block not only realizes the fixing and "shaping" of the anchor hook during construction, ensuring the smooth progress of construction, but also, due to the allowance of the through hole and the effect of internal stress, this application can buffer and release the thermal expansion stress and rotational shear stress during use, thereby effectively avoiding and reducing stress damage and structural cracking, and improving the stability of the composite inner lining structure layer.

[0023] Furthermore, in the aforementioned rotary kiln composite lining structure, within the mounting through hole, the portion of the transition connection near the anchoring ends of the first and second anchoring arms is welded to the wall of the mounting through hole; the portion of the transition connection away from the anchoring ends of the first and second anchoring arms has a flexible space between it and the wall of the mounting through hole.

[0024] The bottom surface of the fixing block is a rectangular welding surface, and the two sides of the rectangular welding surface along the length direction are chamfered to facilitate the fixing block to be tightly welded to the cylinder through the rectangular welding surface;

[0025] The anchoring hook has a V-shaped or U-shaped structure, and the included angle between the first anchoring arm and the second anchoring arm is 40-65°. The anchoring end of the first anchoring arm is provided with a first hook portion, and the anchoring end of the second anchoring arm is provided with a second hook portion. The bending directions of the first hook portion and the second hook portion are opposite.

[0026] The axial and circumferential spacing between the fixing blocks of two adjacent anchoring structures on the inner wall of the rotary kiln cylinder is 180-250mm, and the fixing blocks of two adjacent anchoring structures are set on different planes.

[0027] The total length of the anchoring structure along the length of the anchor hook is the total thickness of the working layer and the functional layer in the rotary kiln composite lining minus 30-150 mm.

[0028] In the above technical solution, the length design of the anchoring structure and the structural design of the anchoring hook enable the anchoring hook to have a larger force-bearing area and higher anchoring capacity, thereby improving the overall integrity of the rotary kiln composite lining structure. The anchoring structure, through appropriate arrangement density, can provide uniform tensile force, while the adjacent fixing blocks forming a certain size can allow the insulation layer material to be attached to the reflective layer at a certain size. The anisotropic arrangement of the anchoring hooks can achieve balanced force distribution, improve the overall anchoring capacity of the anchoring hooks, and at the same time, can uniformly release thermal expansion stress, reducing the destructive effect of thermal stress on the structural layer.

[0029] In the above technical solution, by cutting a chamfer on the rectangular welding surface, the two sides of the rectangular welding surface are naturally formed into a bevel. Compared with right-angle welding, the penetration depth of the weld is deeper and the weld is stronger. In addition, right-angle welding has the problem of thermal stress concentration, which makes it easy to crack at high temperature. However, after chamfering, the welding transition is smooth, which disperses the thermal stress and makes it less prone to cracking.

[0030] Furthermore, in the rotary kiln composite lining structure, the working layer is a fiber-reinforced porous mullite castable, comprising the following components by weight percentage: 28-32% high-alumina bauxite, 2-3% silica powder, 20-30% porous mullite, 0.8-1.5% pretreated steel fiber, 6-8% calcium aluminate cement, 2-4% α-Al2O3 powder, 0.3-0.7% water-reducing agent, 6-8% water, and the balance being corundum.

[0031] In the above technical solution, corundum possesses high hardness, high toughness, and good thermal shock resistance, enabling it to form a "rigid skeleton" for the castable with high-alumina bauxite. Porous mullite can be considered a damping and heat insulation unit, and its porous structure can effectively blunt crack tips and absorb thermal stress, ensuring the mechanical strength of the working layer. Adding an appropriate amount of high-strength steel fiber can improve the mechanical strength of the castable, and the steel fiber can absorb stress like a "toughening agent," preventing microcrack propagation. Ultimately, through the combined effect of the components, a working layer with high mechanical strength, good thermal insulation, and strong thermal shock stability is obtained, effectively balancing the contradictory requirements of "strength" and "thermal insulation."

[0032] Furthermore, in the fiber-reinforced porous mullite castable, the pretreated steel fiber is obtained by combining steel fiber with aluminum hydroxide micro powder.

[0033] In the above technical solution, aluminum hydroxide (Al(OH)3) is used as the aluminum source. During heating, it decomposes to generate highly reactive alumina (Al2O3). This newly formed alumina has a high surface energy and its reactivity is much higher than that of directly used alumina powder. Under high temperature conditions, it can react with the silicon source material (silica micropowder) in the matrix to generate a stable mullite phase. At the same time, water vapor is released during the pyrolysis of aluminum hydroxide, which can generate a large number of micropores inside the material. Due to the high reactivity of the newly formed alumina, it can react at a lower temperature. The reaction allows for the timely utilization of the microporous structure formed after pyrolysis, ultimately resulting in the in-situ formation of a high-porosity mullite phase on the surface of the highly thermally conductive steel fibers. This creates a dense insulating layer that effectively blocks heat transfer from the steel fibers. Simultaneously, because the mullite phase is formed in situ on the steel fiber surface, the steel fibers can specifically reinforce the microporous mullite phase, preventing localized stress defects at the pores. Furthermore, the generated mullite phase exhibits good compatibility with the porous mullite in the matrix, allowing them to integrate and effectively improve the material's overall integrity and structural stability. Finally, through the synergistic effect of the steel fibers and the porous mullite phase, the working layer achieves excellent thermal insulation performance and high mechanical strength.

[0034] Furthermore, in the fiber-reinforced porous mullite castable, the preparation process of the pretreated steel fibers includes the following:

[0035] A1. Immerse the steel fibers in the stripping agent, clean until neutral, and dry to obtain clean steel fibers;

[0036] A2. Immerse the clean steel fiber in acid solution to etch the surface of the steel fiber, then clean it until neutral and dry it to obtain roughened steel fiber.

[0037] A3. The roughened steel fibers are soaked in a carboxymethyl cellulose solution and filtered to obtain a wet roughened steel fiber material.

[0038] A4. Mix the roughened steel fiber wet material with aluminum hydroxide micro powder evenly so that the aluminum hydroxide micro powder is evenly attached to the surface of the roughened steel fiber to obtain pretreated steel fiber.

[0039] In the above technical solution, etching the steel fibers can form a pit structure on the smooth surface of the steel fibers, providing effective adhesion and anchoring sites for aluminum hydroxide micropowder. This allows the aluminum hydroxide micropowder to be effectively interlocked between the steel fibers and the matrix material, preventing the steel fibers from falling off and slipping under stress. At the same time, it enables the steel fibers to form an integral whole with the mullite phase generated in situ on their surface and the matrix material, improving the integrity of the working layer. This achieves targeted reinforcement of porous mullite by the steel fibers, significantly enhancing its mechanical reinforcement effect.

[0040] The technical solution of the present invention achieves the following beneficial technical effects:

[0041] 1. The rotary kiln composite lining structure provided by this invention integrates the concepts of mechanical reinforcement and energy-saving protection through a structural design of "working layer + functional layer + anchoring structure," achieving excellent structural stability and thermal insulation performance. A layered thermal protection system is formed by the efficient reflection of radiant heat by the reflective layer, the synergistic blocking of heat conduction by the insulation and heat-resistant layers, the corrosion resistance and stress buffering of the protective layer, and the wear resistance and high-temperature erosion resistance of the working layer. Combined with the quasi-flexible connection system in the anchoring structure, the rotary kiln can maintain low thermal conductivity and reduce the outer surface temperature of the kiln shell while achieving high mechanical strength, effectively extending the service life of the rotary kiln lining and achieving the dual goals of "longevity" and "energy saving." Practical application verification shows that the rotary kiln shell temperature can be stably controlled below 150℃, significantly improving the safety of equipment operation and energy utilization efficiency.

[0042] 2. The anchoring structure provided by this invention has low manufacturing cost and high installation flexibility. It transforms the traditional rigid connection of "anchor-rotary kiln shell" into a quasi-flexible connection system of "anchor hook-fixing block-rotary kiln shell". The anchoring structure has a certain degree of flexibility in the circumferential and radial directions, effectively reducing shear stress and expansion stress, and improving the overall service life and overall insulation effect of the rotary kiln lining. After passing through the installation through hole, the anchor hook is flexibly fixed to the fixing block. This connection method allows the anchor hook to have a certain amount of movement within the through hole while ensuring connection strength, reducing the thermal expansion stress and shear stress during rotation of the rotary kiln. At the same time, the anisotropic arrangement of the anchor hooks can improve the overall anchoring capacity of the anchor hooks, effectively release thermal expansion stress, and significantly improve the overall stability and service life of the structure.

[0043] 3. In the working layer, pretreated steel fibers (surface-roughened steel fibers loaded with aluminum hydroxide micro powder) are introduced, allowing the highly active alumina generated by the decomposition of aluminum hydroxide at high temperature to react with the silicon source, generating a mullite phase in situ. At the same time, water vapor is released to form micropores. This not only utilizes the high strength of the steel fibers to construct a reinforcing skeleton, but also achieves targeted reinforcement of porous mullite (mechanical weak points) by the high-strength steel fibers through the in-situ generated porous mullite phase and its synergistic effect with the porous mullite in the matrix. Thus, while ensuring excellent thermal insulation performance, the mechanical strength of the working layer is significantly improved. Attached Figure Description

[0044] Figure 1 A schematic diagram of the composite lining structure of the rotary kiln of the present invention;

[0045] Figure 2 Figure 1 Enlarged view of section A in the middle;

[0046] Figure 3 A schematic diagram of the anchoring structure in the rotary kiln composite lining structure of the present invention;

[0047] Figure 4 Figure 3 Enlarged view of section B in the middle;

[0048] Figure 5 Front view of the anchoring hook in the rotary kiln composite lining structure of the present invention;

[0049] Figure 6 A side view of the anchoring hook in the rotary kiln composite lining structure of the present invention;

[0050] Figure 7 One of the schematic diagrams showing the installation of two adjacent anchoring structures in the rotary kiln composite lining structure of the present invention;

[0051] Figure 8 The second schematic diagram of the installation of two adjacent anchoring structures in the rotary kiln composite lining structure of the present invention;

[0052] Figure 9 The third schematic diagram of the installation of two adjacent anchoring structures in the rotary kiln composite lining structure of the present invention;

[0053] Figure 10 Photographs of the combined metal anchors in the composite lining structure of the rotary kiln of the present invention at the completion stage.

[0054] Figure 11 Photographs of the completed insulation layer in the rotary kiln composite lining structure of this invention.

[0055] Figure 12 Photographs of the completed protective layer in the rotary kiln composite lining structure of this invention;

[0056] Figure 13 Photographs of the completed heat insulation layer in the rotary kiln composite lining structure of this invention.

[0057] Figure 14 Photographs of the working layer during the construction stage of the rotary kiln composite lining structure of this invention;

[0058] The reference numerals in the figure are as follows: 1-reflective layer; 2-insulation layer; 3-protective layer; 4-heat insulation layer; 5-working layer; 6-anchoring structure; 61-fixing block; 611-installation through hole; 612-chamfer; 62-anchoring hook; 621-first anchoring arm; 6211-first bend; 622-second anchoring arm; 6221-second bend; 623-transition connection section; 20-functional layer. Detailed Implementation

[0059] Example 1

[0060] A composite lining for a rotary kiln, such as Figure 1 and Figure 2 As shown, the structure includes a working layer 5, a functional layer 20, and an anchoring structure 6. The functional layer 20 is located between the working layer 5 and the inner wall of the rotary kiln. The functional layer 20 is one or a combination of two or more of the following: a reflective layer 1, a heat insulation layer 2, a protective layer 3, and a heat insulation layer 4. The anchoring structure 6 is equally spaced along the axial and circumferential directions of the inner wall of the rotary kiln and extends through the functional layer 20 from the inner wall of the rotary kiln toward the interior of the rotary kiln and into the working layer 5.

[0061] like Figure 3 As shown, the anchoring structure 6 includes a fixing block 61 and an anchoring hook 62 installed on the fixing block 61. The fixing block 61 is fixedly installed on the inner wall of the rotary kiln cylinder. The anchoring hook 62 is flexibly fixedly connected to the fixing block 61, so that the anchoring hook 62 releases thermal expansion stress under high temperature conditions, thereby extending the service life of the anchoring hook 62 and improving the stability of the lining structure.

[0062] Furthermore, the fixing block 61 is provided with a mounting through hole 611, and the anchoring hook 62 passes through the mounting through hole 611; as Figure 5 and Figure 6As shown, the anchoring hook 62 includes a first anchoring arm 621, a second anchoring arm 622, and a transition connecting section 623 connecting the first anchoring arm 621 and the second anchoring arm 622. The anchoring hook 62 is disposed within the mounting through hole 611 via the transition connecting section 623. Within the mounting through hole 611, the transition connecting section 623 is partially fixedly connected to the hole wall of the mounting through hole 611, while the remaining area is a flexible space, so that a flexible fixed connection capable of slight extension and swaying is formed between the anchoring hook 62 and the fixing block 61. Furthermore, within the mounting through hole 611, the portion of the transition connecting section 623 near the anchoring ends of the first anchoring arm 621 and the second anchoring arm 622 is welded to the hole wall of the mounting through hole 611; the portion of the transition connecting section 623 away from the anchoring ends of the first anchoring arm 621 and the second anchoring arm 622 is a flexible space between itself and the hole wall of the mounting through hole 611. In this example, the anchor hook 62 is a cylindrical body with a uniform diameter, and the quasi-flexible connecting through hole is a circular through hole slightly larger than the diameter of the anchor hook 62. This makes the contact surface between the transition connecting section 623 and the quasi-flexible connecting through hole a circular surface. During welding, spot welding is performed on the semi-circular surfaces near the anchoring ends of the first anchoring arm 621 and the second anchoring arm 622, while the semi-circular surfaces away from the anchoring ends of the first anchoring arm 621 and the second anchoring arm 622 are not welded. This results in half of the space between the transition connecting section 623 and the quasi-flexible connecting through hole forming a fixed connection, and the other half forming a flexible space, thereby achieving a flexible fixed connection between the anchor hook 62 and the fixing block 61. Under high-temperature conditions, the anchor hook 62 can achieve slight extension and oscillation, thereby releasing thermal expansion stress and extending its service life.

[0063] like Figure 4 As shown, the bottom surface of the fixing block 61 is a rectangular welding surface. The two sides of the rectangular welding surface along the length direction are cut with chamfers 612 to facilitate the tight welding of the fixing block 61 to the cylinder through the rectangular welding surface. By cutting chamfers 612 on the rectangular welding surface, the two sides of the rectangular welding surface are naturally formed with bevels. Compared with right angle welding, the penetration depth of welding through bevels is deeper and the weld is stronger. In addition, right angle welding has the problem of heat stress concentration, which makes it easy to crack at high temperature. However, after chamfering, the welding transition is smooth, which disperses heat stress and makes it less prone to cracking.

[0064] The anchor hook 62 has a V-shaped or U-shaped structure, and the angle between the first anchor arm 621 and the second anchor arm 622 is 40-65°. Further, the difference between the U-shaped and V-shaped structures lies in the transition connection section 623, wherein, as... Figure 5 As shown, the transition section 623 of the V-shaped structure is a smooth arc segment, as... Figure 9 As shown, the transition connection section 623 of the U-shaped structure is a U-shaped connection section. For example... Figure 1 As shown, in this example, the anchor hook 62 has a V-shaped structure, and the angle between the first anchor arm 621 and the second anchor arm 622 is 50°. By setting the angle of the anchor hook 62, the anchoring capacity of the anchor hook 62 can be greatly improved, enhancing the overall integrity of the rotary kiln composite lining structure. Furthermore, as... Figure 9 As shown, the anchoring hook 62 can also be a U-shaped structure, which can be selected by those skilled in the art according to actual needs.

[0065] like Figure 6 As shown, the anchoring end of the first anchoring arm 621 is provided with a first hook portion, and the anchoring end of the second anchoring arm 622 is provided with a second hook portion, and the bending directions of the first hook portion and the second hook portion are opposite. The opposite bending directions of the first hook portion and the second hook portion enable balanced force distribution and improve the overall anchoring capacity of the anchoring hook 62. Here, the opposite bending directions of the first hook portion and the second hook portion have at least two possibilities. The first possibility is as follows: Figure 7 As shown, both the first hook portion and the second hook portion are bent in a direction perpendicular to the plane containing the first anchoring arm 621 and the second anchoring arm 622. Specifically, the first hook portion bends to one side of the plane containing the first anchoring arm 621 and the second anchoring arm 622, and the second hook portion bends to the other side of the plane containing the first anchoring arm 621 and the second anchoring arm 622. In the second case, as... Figure 8 and 9 As shown, both the first hook portion and the second hook portion are disposed on the same plane as the first anchoring arm 621 and the second anchoring arm 622. The first hook portion bends towards the first anchoring arm 621 in an inclined direction, and the second hook portion bends towards the second anchoring arm 622 in an inclined direction. Based on this, the shape of the anchoring hook 62 includes at least four types. The first type, as shown... Figure 7 As shown, the V-shaped structure with the bending direction perpendicular to the plane containing the first anchoring arm 621 and the second anchoring arm 622; the second type, as... Figure 8 As shown, the V-shaped structure with the bending direction parallel to the plane containing the first anchoring arm 621 and the second anchoring arm 622; the third type, not shown in the figure, has a U-shaped structure with the bending direction perpendicular to the plane containing the first anchoring arm 621 and the second anchoring arm 622; the fourth type, as shown... Figure 9 As shown, the U-shaped structure with the bending direction is parallel to the plane containing the first anchoring arm 621 and the second anchoring arm 622;

[0066] The axial and circumferential spacing of the fixing blocks 61 of two adjacent anchoring structures 6 on the inner wall of the rotary kiln cylinder is 180-250mm, and the fixing blocks 61 of two adjacent anchoring structures 6 are set on different planes; the rotary kiln combined metal anchors can provide uniform tensile force through appropriate arrangement density, and the adjacent fixing blocks 61 form a certain size, which can make the insulation layer 2 material fit onto the reflective layer 1 at a certain size; the total length of the anchoring structure 6 along the length direction of the anchor hook 62 is the total thickness of the working layer 5 and the functional layer 20 in the rotary kiln composite lining minus 30-150mm. The length design of the rotary kiln combined metal anchors can improve the integrity of the rotary kiln composite lining structure.

[0067] The rotary kiln composite lining structure of this application is prepared by the following steps: A fixing block 61 is welded to the inner wall of the rotary kiln cylinder. The axial and circumferential distance between the fixing blocks 61 and the rotary kiln cylinder is 220mm. A V-shaped anchor hook 62 is passed through the mounting through hole 611 of the fixing block 61 and temporarily fixed to the fixing block 61 by spot welding. The height of the anchoring structure is 200mm. Adjacent anchor hooks 62 are arranged in opposite directions. Then, a functional layer 20 is constructed on the inner surface of the rotary kiln. The functional layer 20, from the inner wall of the rotary kiln cylinder towards the interior of the rotary kiln, consists of a reflective layer 1, a heat insulation layer 2, a protective layer 3, and a heat insulation layer 4, in that the reflective layer 1 is a 0.2mm nano-ceramic heat-insulating coating. Figure 11 As shown, insulation layer 2 is a 20mm thick nano-insulation board, such as... Figure 12 As shown, protective layer 3 is a 10mm thick hydrophobic aluminum silicate fiberboard, such as... Figure 13 As shown, insulation layer 4 is a 70mm thick high-temperature resistant lightweight heat-insulating spray coating, such as... Figure 14 As shown, working layer 5 is a steel fiber corundum mullite pumped material.

[0068] like Figure 1As shown, the combination of nano-insulation board (insulation layer 2) and hydrophobic aluminum silicate fiber board (protective layer 3) effectively prevents moisture from the high-temperature resistant lightweight heat-insulating spray coating (insulation layer 4) from penetrating into the nano-insulation board (insulation layer 2). Furthermore, the hydrophobic aluminum silicate fiber board (protective layer 3) prevents excessive heat transfer to the nano-insulation board (insulation layer 2), ensuring that it does not sinter or pulverize during use, thus fully utilizing the heat insulation effect of the nanomaterials. Simultaneously, the hydrophobic aluminum silicate fiber board (protective layer 3) structurally buffers the stress transferred by the high-temperature resistant lightweight heat-insulating spray coating (insulation layer 4), ensuring the structural integrity of insulation layer 2. The steel fiber corundum mullite pumped material (working layer 6) is tightly attached to the high-temperature resistant insulation layer, effectively preventing high-temperature flue gas from penetrating inward and enhancing the heat insulation effect. The reflective layer 1 is a nano-ceramic heat-insulating coating layer composed of nano-scale hollow materials with a thermal emissivity of 0.8-0.98. It can increase thermal efficiency, effectively reduce heat diffusion to the outside, and has excellent reflective heat transfer performance, resulting in significant energy-saving effects. It can achieve an energy saving rate of 7.8% for hot air and reduce the temperature of the rotary kiln steel shell by 8°C. At the same time, the nano-ceramic heat-insulating coating (reflective layer 1) forms a hard ceramic coating on the inner wall of the rotary kiln steel shell, which can effectively block the corrosion of the cylinder by high chlorine, high sulfur, and high alkaline atmospheres, ensuring the safe operation of the rotary kiln. The protective layer 3 is a hydrophobic aluminum silicate fiberboard, which is waterproof, high temperature resistant, has low thermal conductivity, good thermal insulation performance, and is lightweight. The hydrophobic aluminum silicate fiberboard is placed between the high temperature resistant lightweight thermal insulation spray coating (thermal insulation layer 4) and the nano thermal insulation board (thermal insulation layer 2). It can effectively reduce the temperature of the heat transferred from the high temperature resistant lightweight thermal insulation spray coating (thermal insulation layer 4), so that the temperature of the heat received by the nano thermal insulation board (thermal insulation layer 2) is significantly reduced, thereby increasing the service life of the nano thermal insulation board (thermal insulation layer 2) and preventing the stress transferred from the thermal insulation layer 4 from affecting the nano thermal insulation board (thermal insulation layer 2), thus achieving the best thermal insulation and protection effect.

[0069] Example 2

[0070] A composite lining for a rotary kiln is prepared by the following steps:

[0071] S1. Weld the fixing block 61 to the inner wall of the rotary kiln cylinder. The axial and circumferential distance of the fixing block 61 in the rotary kiln cylinder is 220mm. Pass the V-shaped anchor hook 62 through the installation through hole 611 of the fixing block 61 and fix it to the fixing block 61 by spot welding. The height of the anchor structure is 200mm. Adjacent anchor hooks 62 are arranged in opposite directions. Then, construct the functional layer 20 on the inner surface of the rotary kiln. The functional layer 20 is composed of a reflective layer 1, a heat insulation layer 2, a protective layer 3 and a heat insulation layer 4 in sequence from the inner wall of the rotary kiln cylinder to the inside of the rotary kiln. Among them, the reflective layer 1 is a 0.2mm nano-ceramic heat-insulating coating, the heat insulation layer 2 is a 20mm nano heat insulation board, the protective layer 3 is a 10mm thick hydrophobic aluminum silicate fiber board, and the heat insulation layer 4 is a 70mm thick high-temperature resistant lightweight heat insulation spray coating.

[0072] S2. The fiber-reinforced porous mullite castable is cast onto the surface of the dried functional layer 20 using a casting machine to obtain a working layer 5 with a thickness of 180 mm. The fiber-reinforced porous mullite castable includes the following components: 300 kg of high-alumina bauxite, 25 kg of silica powder, 250 kg of porous mullite, 10 kg of pretreated steel fiber, 70 kg of calcium aluminate cement, 30 kg of α-Al2O3 powder, 5 kg of water-reducing agent (sodium tripolyphosphate), 70 kg of water, and 240 kg of brown corundum.

[0073] S3. The blank in working layer 5 is baked, shaped, and demolded to obtain the rotary kiln composite lining.

[0074] The preparation of pretreated steel fibers includes the following:

[0075] A1. Immerse 446 type steel fibers with a length of 10-30mm and a diameter of 0.2-0.3mm in a stripping agent, clean until neutral, and dry to obtain clean steel fibers;

[0076] A2. Immerse the clean steel fiber in a 10% hydrochloric acid solution for 1 minute to etch the surface of the steel fiber, then clean it until neutral and dry it to obtain roughened steel fiber.

[0077] A3. The roughened steel fibers are soaked in an aqueous solution of sodium carboxymethyl cellulose with a mass fraction of 2%, filtered, and the roughened steel fiber wet material is obtained.

[0078] A4. Mix the roughened steel fiber wet material with aluminum hydroxide micro powder with a particle size of 1000 mesh evenly, so that the aluminum hydroxide micro powder is evenly attached to the surface of the roughened steel fiber, and obtain pretreated steel fiber.

[0079] Example 3

[0080] The only difference between this embodiment and Embodiment 1 is that the steel fibers in the working layer 5 (fiber-reinforced porous mullite castable) are not pretreated; that is, the pretreated steel fibers are replaced with ordinary steel fibers. Specifically:

[0081] A composite lining for a rotary kiln is prepared by the following steps:

[0082] S1. Weld the fixing block 61 to the inner wall of the rotary kiln cylinder. The axial and circumferential distance of the fixing block 61 in the rotary kiln cylinder is 220mm. Pass the V-shaped anchor hook 62 through the installation through hole 611 of the fixing block 61 and fix it to the fixing block 61 by spot welding. The height of the anchor structure is 200mm. Adjacent anchor hooks 62 are arranged in opposite directions. Then, construct the functional layer 20 on the inner surface of the rotary kiln. The functional layer 20 is composed of a reflective layer 1, a heat insulation layer 2, a protective layer 3 and a heat insulation layer 4 in sequence from the inner wall of the rotary kiln cylinder to the inside of the rotary kiln. Among them, the reflective layer 1 is a 0.2mm nano-ceramic heat-insulating coating, the heat insulation layer 2 is a 20mm nano heat insulation board, the protective layer 3 is a 10mm thick hydrophobic aluminum silicate fiber board, and the heat insulation layer 4 is a 70mm thick high-temperature resistant lightweight heat insulation spray coating.

[0083] S2. The fiber-reinforced porous mullite castable is cast onto the surface of the dried functional layer 20 using a casting machine to obtain a working layer 5 with a thickness of 180 mm. The fiber-reinforced porous mullite castable includes the following components: 300 kg of high-alumina bauxite, 25 kg of silica powder, 250 kg of porous mullite, 10 kg of steel fiber, 70 kg of calcium aluminate cement, 30 kg of α-Al2O3 powder, 5 kg of water-reducing agent (sodium tripolyphosphate), 70 kg of water, and 240 kg of brown fused alumina.

[0084] S3. The blank in working layer 5 is baked, shaped, and demolded to obtain the rotary kiln composite lining.

[0085] Example 4

[0086] The only difference between this embodiment and Embodiment 1 is that aluminum hydroxide micropowder was not added to the components of working layer 5 (fiber-reinforced porous mullite castable) during the preparation of the pretreated steel fibers. Specifically:

[0087] A composite lining for a rotary kiln is prepared by the following steps:

[0088] S1. Weld the fixing block 61 to the inner wall of the rotary kiln cylinder. The axial and circumferential distance of the fixing block 61 in the rotary kiln cylinder is 220mm. Pass the V-shaped anchor hook 62 through the installation through hole 611 of the fixing block 61 and fix it to the fixing block 61 by spot welding. The height of the anchor structure is 200mm. Adjacent anchor hooks 62 are arranged in opposite directions. Then, construct the functional layer 20 on the inner surface of the rotary kiln. The functional layer 20 is composed of a reflective layer 1, a heat insulation layer 2, a protective layer 3 and a heat insulation layer 4 in sequence from the inner wall of the rotary kiln cylinder to the inside of the rotary kiln. Among them, the reflective layer 1 is a 0.2mm nano-ceramic heat-insulating coating, the heat insulation layer 2 is a 20mm nano heat insulation board, the protective layer 3 is a 10mm thick hydrophobic aluminum silicate fiber board, and the heat insulation layer 4 is a 70mm thick high-temperature resistant lightweight heat insulation spray coating.

[0089] S2. The fiber-reinforced porous mullite castable is cast onto the surface of the dried functional layer 20 using a casting machine to obtain a working layer 5 with a thickness of 180 mm. The fiber-reinforced porous mullite castable includes the following components: 300 kg of high-alumina bauxite, 25 kg of silica powder, 250 kg of porous mullite, 10 kg of pretreated steel fiber, 70 kg of calcium aluminate cement, 30 kg of α-Al2O3 powder, 5 kg of water-reducing agent (sodium tripolyphosphate), 70 kg of water, and 240 kg of brown corundum.

[0090] S3. The blank in working layer 5 is baked, shaped, and demolded to obtain the rotary kiln composite lining.

[0091] The preparation of pretreated steel fibers includes the following:

[0092] A1. Immerse 446 type steel fibers with a length of 10-30mm and a diameter of 0.2-0.3mm in a stripping agent, clean until neutral, and dry to obtain clean steel fibers;

[0093] A2. Immerse the clean steel fiber in a 10% hydrochloric acid solution for 1 minute to etch the surface of the steel fiber, then clean it until neutral and dry it to obtain roughened steel fiber.

[0094] A3. Soak the roughened steel fibers in water, filter, and dry to obtain pretreated steel fibers.

[0095] Example 5

[0096] The only difference between this embodiment and Embodiment 1 is that, in the preparation of the pretreated steel fibers in the working layer 5 (fiber-reinforced porous mullite castable), no roughening treatment was performed on the steel fibers. Specifically:

[0097] A composite lining for a rotary kiln is prepared by the following steps:

[0098] S1. Weld the fixing block 61 to the inner wall of the rotary kiln cylinder. The axial and circumferential distance of the fixing block 61 in the rotary kiln cylinder is 220mm. Pass the V-shaped anchor hook 62 through the installation through hole 611 of the fixing block 61 and fix it to the fixing block 61 by spot welding. The height of the anchor structure is 200mm. Adjacent anchor hooks 62 are arranged in opposite directions. Then, construct the functional layer 20 on the inner surface of the rotary kiln. The functional layer 20 is composed of a reflective layer 1, a heat insulation layer 2, a protective layer 3 and a heat insulation layer 4 in sequence from the inner wall of the rotary kiln cylinder to the inside of the rotary kiln. Among them, the reflective layer 1 is a 0.2mm nano-ceramic heat-insulating coating, the heat insulation layer 2 is a 20mm nano heat insulation board, the protective layer 3 is a 10mm thick hydrophobic aluminum silicate fiber board, and the heat insulation layer 4 is a 70mm thick high-temperature resistant lightweight heat insulation spray coating.

[0099] S2. The fiber-reinforced porous mullite castable is cast onto the surface of the dried functional layer 20 using a casting machine to obtain a working layer 5 with a thickness of 180 mm. The fiber-reinforced porous mullite castable includes the following components: 300 kg of high-alumina bauxite, 25 kg of silica powder, 250 kg of porous mullite, 10 kg of pretreated steel fiber, 70 kg of calcium aluminate cement, 30 kg of α-Al2O3 powder, 5 kg of water-reducing agent (sodium tripolyphosphate), 70 kg of water, and 240 kg of brown corundum.

[0100] S3. The blank in working layer 5 is baked, shaped, and demolded to obtain the rotary kiln composite lining.

[0101] The preparation of pretreated steel fibers includes the following:

[0102] A1. Immerse 446 type steel fibers with a length of 10-30mm and a diameter of 0.2-0.3mm in a stripping agent, clean until neutral, and dry to obtain clean steel fibers;

[0103] A2. Soak clean steel fibers in an aqueous solution of sodium carboxymethyl cellulose with a mass fraction of 2%, filter, and obtain wet steel fiber material;

[0104] A3. Mix the wet steel fiber with aluminum hydroxide micro powder with a particle size of 1000 mesh evenly to make the roughened steel fiber surface uniformly coated with aluminum hydroxide micro powder, and obtain pretreated steel fiber.

[0105] Proof of effectiveness

[0106] 1. The rotary kiln composite lining prepared in Examples 1-5 can reduce the rotary kiln shell temperature to below 150℃. Through actual operation comparison, the rotary kiln composite lining provided in this example saves 30m³ of natural gas per ton of product compared to traditional lining structures. 3 The energy saving rate reaches 20%;

[0107] 2. The fiber-reinforced porous mullite castable used in the working layer of Examples 2-5 was injected into the sample mold and cured, then dried and calcined at high temperature. The mechanical strength (high-temperature flexural strength, 1100℃) of the sample was tested according to GB / T 3002-2017, and the thermal insulation performance (thermal conductivity, 500℃) of the sample was also tested. The specific test results are shown in Table 1:

[0108] Table 1

[0109]

[0110] As can be seen from Examples 2-5 and the data in Table 1, the fiber-reinforced porous mullite castable used in the working layer of Examples 2-5 has a high-temperature flexural strength of over 9.6 MPa and a thermal conductivity of no more than 1.12 W / (m·K), indicating that the working layer material of the rotary kiln composite lining provided by the present invention has high mechanical strength and good thermal insulation performance.

[0111] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A composite lining structure for a rotary kiln, characterized in that, It includes a working layer (5), a functional layer (20) and an anchoring structure (6), wherein the functional layer (20) is located between the working layer (5) and the inner wall of the rotary kiln cylinder; the functional layer (20) is one or a combination of two or more of the following: a reflective layer (1), a heat insulation layer (2), a protective layer (3) and a heat insulation layer (4); The anchoring structure (6) is provided at equal intervals along the axial and circumferential directions of the inner wall of the rotary kiln cylinder and extends through the functional layer (20) from the inner wall of the rotary kiln cylinder toward the interior of the rotary kiln and into the working layer (5). The anchoring structure (6) includes a fixing block (61) and an anchoring hook (62) installed on the fixing block (61). The fixing block (61) is fixedly installed on the inner wall of the rotary kiln cylinder. The anchoring hook (62) is flexibly fixedly connected to the fixing block (61), so that the anchoring hook (62) releases thermal expansion stress under high temperature conditions, thereby extending the service life of the anchoring hook (62) and improving the stability of the lining structure.

2. The rotary kiln composite lining structure according to claim 1, characterized in that, The functional layer (20) includes a reflective layer (1) and a main functional layer. The main functional layer is one or a combination of a protective layer (3) and a heat insulation layer (4). The reflective layer (1) is a nano-ceramic heat-insulating coating. The reflective layer (1) is located on the inner wall of the rotary kiln cylinder. The protective layer (3) is one or a combination of two or more of the following: hydrophobic aluminum silicate fiber board, hydrophobic aluminum silicate fiber felt, hydrophobic aluminum silicate fiber blanket, and hydrophobic aluminum silicate fiber paper. The heat insulation layer (4) is one or a combination of two or more of the following: high-temperature resistant lightweight spray coating, high-temperature resistant lightweight coating, high-temperature resistant medium-weight spray coating, and high-temperature resistant medium-weight coating. The heat insulation layer (4) is in direct contact with the working layer (5).

3. The rotary kiln composite lining structure according to claim 1, characterized in that, The functional layer (20) is one or a combination of the protective layer (3) and the heat insulation layer (4). The protective layer (3) is one or a combination of two or more of the following: hydrophobic aluminum silicate fiberboard, hydrophobic aluminum silicate fiber felt, hydrophobic aluminum silicate fiber blanket and hydrophobic aluminum silicate fiber paper. The heat insulation layer (4) is one or a combination of two or more of the following: high temperature resistant lightweight spray paint, high temperature resistant lightweight coating, high temperature resistant medium-density spray paint and high temperature resistant medium-density coating.

4. The rotary kiln composite lining structure according to claim 1, characterized in that, The functional layer (20) includes a thermal insulation layer (2) and a protective layer (3). The thermal insulation layer (2) is one or a combination of nano-insulation board and aerogel felt. The protective layer (3) is one or a combination of more than two of hydrophobic aluminum silicate fiber board, hydrophobic aluminum silicate fiber felt, hydrophobic aluminum silicate fiber blanket and hydrophobic aluminum silicate fiber paper.

5. The rotary kiln composite lining structure according to claim 1, characterized in that, From the inner wall of the rotary kiln cylinder towards the interior of the rotary kiln, a reflective layer (1), a heat insulation layer (2), a protective layer (3), a heat insulation layer (4), and a working layer (5) are sequentially arranged. The reflective layer (1) is a nano-ceramic heat-insulating coating with a thickness of 0.2-2 mm. The heat insulation layer (2) is one or a combination of nano-insulating board and aerogel felt with a thickness of 5-40 mm. The protective layer (3) is a hydrophobic aluminosilicate fiber board, a hydrophobic aluminosilicate fiber felt, or a hydrophobic aluminosilicate fiber. The heat insulation layer (4) is one or more of the following: a blanket and a hydrophobic aluminosilicate fiber paper, with a thickness of 1-50 mm. The heat insulation layer (4) is one or more of the following: a high-temperature resistant lightweight spray coating, a high-temperature resistant lightweight coating, a high-temperature resistant medium-weight spray coating, and a high-temperature resistant medium-weight coating, with a thickness of 30-100 mm. The working layer (5) is one or more of the following: a refractory brick, a precast block, a castable, a ramming material, a heavy pumping material, and a heavy spray coating, with a thickness of 100-300 mm.

6. The rotary kiln composite lining structure according to any one of claims 1-5, characterized in that, The fixing block (61) is provided with a mounting through hole (611), and the anchor hook (62) passes through the mounting through hole (611); The anchor hook (62) includes a first anchor arm (621), a second anchor arm (622), and a transition connecting section (623) connecting the first anchor arm (621) and the second anchor arm (622). The anchor hook (62) is disposed in the mounting through hole (611) through the transition connecting section (623). Within the mounting through hole (611), the transition connecting section (623) is locally fixedly connected to the hole wall of the mounting through hole (611), while the remaining area is a flexible space, so that a flexible fixed connection that can be slightly extended and oscillated is formed between the anchor hook (62) and the fixing block (61).

7. The rotary kiln composite lining structure according to claim 6, characterized in that, Within the mounting through hole (611), the portion of the transition connecting section (623) near the anchoring ends of the first anchoring arm (621) and the second anchoring arm (622) is welded to the wall of the mounting through hole (611); the portion of the transition connecting section (623) away from the anchoring ends of the first anchoring arm (621) and the second anchoring arm (622) has a flexible space between it and the wall of the mounting through hole (611). The bottom surface of the fixing block (61) is a rectangular welding surface. The rectangular welding surface has chamfers (612) cut on both sides along the length direction so that the fixing block (61) can be tightly welded to the rotary kiln body through the rectangular welding surface. The anchor hook (62) has a V-shaped or U-shaped structure, and the included angle between the first anchor arm (621) and the second anchor arm (622) is 40-65°. The anchoring end of the first anchor arm (621) is provided with a first hook portion (6211), and the anchoring end of the second anchor arm (622) is provided with a second hook portion (6221). The bending directions of the first hook portion (6211) and the second hook portion (6221) are opposite. The axial and circumferential spacing of the fixing blocks (61) of two adjacent anchoring structures (6) on the inner wall of the rotary kiln cylinder is 180-250mm, and the fixing blocks (61) of two adjacent anchoring structures (6) are set on different planes. The total length of the anchoring structure (6) along the length direction of the anchoring hook (62) is the total thickness of the working layer (5) and the functional layer (20) in the rotary kiln composite lining minus 30-150 mm.

8. The rotary kiln composite lining structure according to any one of claims 1-5, characterized in that, The working layer (5) is a fiber-reinforced porous mullite castable, comprising the following components by weight percentage: 28-32% high-alumina bauxite, 2-3% silica powder, 20-30% porous mullite, 0.8-1.5% pretreated steel fiber, 6-8% calcium aluminate cement, 2-4% α-Al2O3 powder, 0.3-0.7% water-reducing agent, 6-8% water, and the balance being corundum.

9. The rotary kiln composite lining structure according to claim 8, characterized in that, The pretreated steel fiber is obtained by combining steel fiber with aluminum hydroxide micro powder.

10. The rotary kiln composite lining structure according to claim 8, characterized in that, The preparation process of the pretreated steel fibers includes the following: A1. Immerse the steel fibers in the stripping agent, clean until neutral, and dry to obtain clean steel fibers; A2. Immerse the clean steel fiber in acid solution to etch the surface of the steel fiber, then clean it until neutral and dry it to obtain roughened steel fiber. A3. The roughened steel fibers are soaked in a carboxymethyl cellulose solution and filtered to obtain a wet roughened steel fiber material. A4. Mix the roughened steel fiber wet material with aluminum hydroxide micro powder evenly so that the aluminum hydroxide micro powder is evenly attached to the surface of the roughened steel fiber to obtain pretreated steel fiber.

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