Rare earth rotary kiln heat preservation structure

Abstract

The application provides a rare earth rotary kiln heat preservation structure, and relates to the technical field of rotary kiln, which comprises a kiln body steel shell, an inner layer heat preservation assembly is arranged on the inner surface of the kiln body steel shell, and an outer layer heat preservation assembly is arranged on the outer surface of the kiln body steel shell. Through the arrangement of the inner layer heat preservation assembly, the working layer is integrally cast and formed without masonry gaps, and the problems of heat flow concentration and local heat loss at the masonry joints are fundamentally eliminated; the multiple mirror stainless steel foils and ceramic fiber paper in the composite reflection layer are alternately superimposed to form a 'radiation heat trap', repeatedly reflect the radiation heat back into the kiln, and significantly inhibit the high-temperature radiation heat transfer; the first heat insulation layer adopts a nano microporous heat insulation plate, the 20-50nm microporous structure in the plate effectively inhibits the gas convection heat transfer, and the added infrared light shielding agent further blocks the radiation heat transfer. The three-layer structure cooperates to make the inner layer heat preservation assembly achieve extremely high equivalent thermal resistance with a smaller thickness, and greatly reduce the heat penetrating through the kiln body steel shell.

Description

Technical Field

[0001] This utility model relates to the field of rotary kiln technology, and more specifically, to a rare earth rotary kiln insulation structure. Background Technology

[0002] In rare earth smelting processes, rotary kilns are crucial equipment for roasting, reducing, or drying rare earth concentrates or intermediate products. Since rare earth roasting temperatures typically need to reach 800℃-1200℃, heat within the kiln is easily lost to the outside through the metal cylinder wall. Traditional rotary kiln insulation structures often consist of a single layer of refractory bricks supplemented with rock wool or aluminosilicate fiber felt, which suffers from problems such as high heat loss, high cylinder surface temperature (often reaching 250℃-350℃), high energy consumption, easy damage to the insulation layer, and poor sealing.

[0003] For example, the "Energy-Saving and Thermal Insulation Structure for Rotary Kilns" disclosed in Chinese Utility Model Patent (Publication No.: CN223153978U) includes a rotary kiln cylinder and a refractory lining disposed inside the cylinder. A composite thermal insulation layer is provided between the inner wall of the cylinder and the refractory lining. This composite thermal insulation layer includes heat insulation boards and a heat-insulating adhesive coating disposed between the heat insulation boards and the inner wall of the cylinder. The heat insulation boards are arranged in a staggered array. This structure, through the superposition of thermal resistance and the staggered arrangement design, reduces the temperature of the outer wall of the cylinder to a certain extent and improves the thermal insulation efficiency. Regarding the aforementioned technologies, this device has some shortcomings. In actual use, a large number of masonry gaps are formed between the insulation board and the refractory bricks. Under high-temperature conditions, the heat flux density at these gaps is significantly concentrated, forming low thermal resistance channels and leading to increased local heat loss. At the same time, this structure only sets up an insulation layer for the inner wall of the cylinder and does not systematically optimize the insulation of the outer wall of the steel shell. As a result, heat can still be directly radiated and dissipated outward through the steel shell, making it difficult to achieve a highly efficient thermal barrier in the entire circumference and cross-section. Overall heat loss is still relatively significant.

[0004] Therefore, we made improvements and proposed a rare earth rotary kiln insulation structure. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a rare earth rotary kiln insulation structure, which solves the problems mentioned in the background section.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A rare earth rotary kiln insulation structure includes a kiln body steel shell, an inner layer insulation component is provided on the inner surface of the kiln body steel shell, and an outer layer insulation component is provided on the outer surface of the kiln body steel shell. The inner insulation component includes a first heat insulation layer disposed on the inner surface of the kiln body steel shell, a composite reflective layer disposed on the inner surface of the first heat insulation layer, and a working layer disposed on the inner surface of the composite reflective layer.

[0007] As a preferred technical solution of this application, the outer heat insulation component includes a second heat insulation layer disposed on the outer surface of the steel shell of the kiln body, an aerogel felt layer disposed on the outer surface of the second heat insulation layer, a microporous calcium silicate board layer disposed on the outer surface of the aerogel felt layer, and a stainless steel corrugated plate protective shell disposed on the outer surface of the microporous calcium silicate board layer.

[0008] As a preferred technical solution of this application, the stainless steel corrugated plate protective shell is provided with a number of T-shaped anchor nails. The T-shaped anchor nails pass through the stainless steel corrugated plate protective shell, the microporous calcium silicate plate layer, the aerogel felt layer and the second heat insulation layer in sequence and are then welded and fixed to the kiln body steel shell.

[0009] As a preferred technical solution of this application, the working layer is a lightweight mullite castable layer poured into the inner wall of the steel shell of the kiln, and the thickness of the working layer is 80-150mm.

[0010] As a preferred technical solution of this application, the first heat insulation layer is a nanoporous heat insulation board, and the thickness of the first heat insulation layer is 20-40mm.

[0011] As a preferred technical solution of this application, the composite reflective layer includes at least two layers of mirror stainless steel foil and ceramic fiber paper located between adjacent mirror stainless steel foils, wherein the mirror stainless steel foil and ceramic fiber paper are alternately stacked.

[0012] As a preferred technical solution of this application, the thickness of the mirror stainless steel foil is 0.05-0.15mm, the thickness of the ceramic fiber paper is 0.5-1.0mm, and the total number of layers of the composite reflective layer is 4-8.

[0013] As a preferred technical solution of this application, the material of the second heat insulation layer is a ceramic heat insulation board.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: In the scheme of this application: 1. By incorporating the inner insulation components, the working layer is integrally cast without any construction gaps, fundamentally eliminating heat concentration and localized heat loss at the construction joints. The composite reflective layer, with its alternating layers of mirror-finished stainless steel foil and ceramic fiber paper, forms a "radiative heat trap," repeatedly reflecting radiative heat back into the kiln, significantly suppressing high-temperature radiative heat transfer. The first insulation layer uses a nanoporous insulation board with an internal 20-50nm microporous structure that effectively suppresses gas convection heat transfer, while the added infrared shielding agent further blocks radiative heat transfer. The synergistic effect of these three layers allows the inner insulation components to achieve extremely high equivalent thermal resistance with a relatively small thickness, significantly reducing the heat transmitted through the kiln's steel shell.

[0015] 2. By setting up the outer insulation components, a second thermal barrier is formed on the outer wall of the kiln's steel shell, which together with the inner insulation components constitutes a dual insulation system of "internal barrier + external attenuation". The second insulation layer uses ceramic insulation board, which is resistant to high temperature and has high compressive strength, providing stable rigid support for the outer layer. The aerogel felt layer has an extremely low thermal conductivity, which can further block residual heat. The microporous calcium silicate board layer has both excellent thermal insulation and mechanical strength, protecting the internal insulation material from external damage. The synergistic effect of the three layers of materials significantly reduces the temperature of the outer wall of the kiln's steel shell, reduces heat loss, and significantly improves the energy utilization efficiency of the rare earth rotary kiln. Attached Figure Description

[0016] Figure 1 A three-dimensional structural diagram of a rare earth rotary kiln insulation structure provided in this application; Figure 2 A schematic diagram of the inner insulation component in a rare earth rotary kiln insulation structure provided in this application; Figure 3 A schematic diagram of the outer insulation component in a rare earth rotary kiln insulation structure provided in this application; Figure 4 A schematic diagram of the composite reflective layer in the insulation structure of a rare earth rotary kiln provided in this application; Figure 5 This is a schematic diagram of the T-shaped anchor nail in the insulation structure of a rare earth rotary kiln provided in this application.

[0017] The image shows: 1. Kiln steel shell; 2. Inner insulation component; 3. Outer insulation component; 4. First insulation layer; 5. Composite reflective layer; 6. Working layer; 7. Microporous calcium silicate board layer; 8. Aerogel felt layer; 9. Second insulation layer; 10. Stainless steel corrugated plate protective shell; 11. T-shaped anchor nails; 12. Mirror stainless steel foil; 13. Ceramic fiber paper. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0020] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] Example 1 Please refer to Figures 1-5 A rare earth rotary kiln insulation structure includes a kiln body steel shell 1, an inner layer insulation component 2 is provided on the inner surface of the kiln body steel shell 1, and an outer layer insulation component 3 is provided on the outer surface of the kiln body steel shell 1. The inner insulation component 2 includes a first heat insulation layer 4 disposed on the inner surface of the kiln body steel shell 1, a composite reflective layer 5 disposed on the inner surface of the first heat insulation layer 4, and a working layer 6 disposed on the inner surface of the composite reflective layer 5.

[0023] Furthermore, the working layer 6 is a lightweight mullite castable layer cast into the inner wall of the steel shell 1 of the kiln. The thickness of the working layer 6 is 80-150mm. Within this range, it can provide sufficient thermal resistance to initially attenuate the high temperature, while avoiding excessive thickness that would occupy the effective space inside the kiln. Compared with traditional heavy refractory bricks, lightweight mullite castable has a low bulk density and low heat capacity, which can reduce the overall weight of the kiln and reduce the energy consumption of the rotary kiln drive. At the same time, its good thermal shock resistance can withstand the frequent heating and cooling cycles during rare earth roasting without cracking or peeling.

[0024] Furthermore, the first insulation layer 4 is a nanoporous insulation board with a thickness of 20-40mm. Within this range, it achieves extremely high equivalent thermal resistance with a small space occupation. When the thickness is less than 20mm, the insulation effect is insufficient, and when the thickness is greater than 40mm, the marginal benefit decreases and the burden on the kiln increases. Its interior contains a silica microporous structure with an average pore size of 20-50nm, which effectively inhibits gas convection heat transfer inside the micropores. It also contains carbon black or silicon carbide infrared shading agent, which can efficiently scatter and absorb infrared radiation transmitted at high temperatures, further blocking the radiation heat transfer channel.

[0025] Furthermore, the composite reflective layer 5 includes at least two layers of mirror stainless steel foil 12 and ceramic fiber paper 13 located between adjacent mirror stainless steel foils 12, with the mirror stainless steel foil 12 and ceramic fiber paper 13 alternately stacked.

[0026] Furthermore, the thickness of the mirror stainless steel foil 12 is 0.05-0.15mm, which ensures that the foil has sufficient structural strength to maintain the flatness of the mirror and obtain a high infrared reflectivity, while avoiding the increase in heat capacity and cost caused by excessive thickness; the thickness of the ceramic fiber paper 13 is 0.5-1.0mm, which is sufficient to form a reliable air gap isolation and thermal resistance layer between adjacent stainless steel foils to prevent interlayer thermal short circuits, while avoiding the waste of space caused by excessive thickness. The total number of composite reflective layers 5 is 4-8 layers. When there are fewer than 4 layers, the number of radiation reflections is insufficient and the heat insulation effect is significantly reduced. When there are more than 8 layers, the marginal benefit decreases and the construction cost increases significantly. Within this range, radiant heat is repeatedly reflected between the multi-layer mirror interfaces to form a "radiative heat trap".

[0027] Example 2 The rare earth rotary kiln insulation structure provided in Example 1 is further optimized. Specifically, the outer insulation component 3 includes a second heat insulation layer 9 disposed on the outer surface of the kiln body steel shell 1, an aerogel felt layer 8 disposed on the outer surface of the second heat insulation layer 9, a microporous calcium silicate board layer 7 disposed on the outer surface of the aerogel felt layer 8, and a stainless steel corrugated plate protective shell 10 disposed on the outer surface of the microporous calcium silicate board layer 7.

[0028] Furthermore, the stainless steel corrugated protective shell 10 is provided with several T-shaped anchor nails 11. The T-shaped anchor nails 11 pass through the stainless steel corrugated protective shell 10, the microporous calcium silicate board layer 7, the aerogel felt layer 8, and the second insulation layer 9 in sequence before being welded and fixed to the kiln body steel shell 1. This forms a reliable mechanical locking structure, preventing relative slippage or loosening between the layers under continuous rotation and vibration conditions of the rotary kiln. At the same time, the anchor nails pass through all the outer insulation layers in sequence, achieving overall compression and positioning of the outer insulation component 3, preventing the aerogel felt layer 8 and the microporous calcium silicate board layer 7 from collapsing or delaminating due to gravity or thermal stress during use.

[0029] Furthermore, the second insulation layer 9 is made of ceramic insulation board. Ceramic insulation board has excellent high-temperature resistance and can work stably for a long time without softening or sintering deformation under high-temperature conditions of 800℃-1200℃ in rare earth calcination. Its low thermal conductivity can effectively block residual heat conducted through the steel shell 1 of the kiln, further reducing the temperature of the outer wall. At the same time, the ceramic insulation board has good compressive strength, which can provide stable rigid support for the outer aerogel felt layer 8 and microporous calcium silicate board layer 7, preventing the outer insulation material from collapsing or shifting during the rotation and vibration of the kiln, thus ensuring the overall structural stability and long service life of the outer insulation component 3.

[0030] The usage process of the rare earth rotary kiln insulation structure provided by this utility model is as follows: When the rotary kiln operates at a high-temperature firing temperature of 800℃-1200℃, the high temperature inside the kiln first acts on the integrally cast working layer 6 without any construction joints. This lightweight mullite castable layer utilizes its low thermal conductivity to initially attenuate the high-temperature heat, fundamentally avoiding the problem of heat flow concentration caused by construction joints. The residual heat passing through the working layer 6 then enters the composite reflective layer 5, which is composed of alternating layers of mirror stainless steel foil 12 and ceramic fiber paper 13. The mirror stainless steel foil 12 reflects the radiant heat back into the kiln along the incident path, while the ceramic fiber paper 13 isolates the direct contact heat transfer between adjacent stainless steel foils and buffers thermal stress. The radiant heat is repeatedly reflected and attenuated layer by layer between the multiple mirror interfaces, forming a "radiative heat trap" effect. After passing through the composite reflective layer 5... The further weakened heat continues to be transferred to the first insulation layer 4. This nanoporous insulation board contains a large number of silica microporous structures with an average pore size of 20-50nm. The pore size is smaller than the mean free path of air molecules, thus effectively inhibiting gas convection heat transfer. Even if the heat is transferred outward through the steel shell 1 of the kiln, it still needs to pass through the second insulation layer 9 ceramic insulation board, the aerogel felt layer 8, and the microporous calcium silicate board layer 7 in sequence. The three layers of external insulation materials work together to form the second thermal barrier on the outer wall. Finally, the trace amount of heat that passes through the outer insulation component 3 is dissipated to the environment through the surface of the stainless steel corrugated protective shell 10. Since the inner insulation component 2 and the outer insulation component 3 together form a dual thermal barrier system of "internal barrier + external attenuation", the technical problems of large heat loss and high energy consumption are effectively solved.

[0031] It should be noted that all components used in this application are standard parts that can be purchased from the market. The specific connection methods of each part adopt conventional methods such as bolts, rivets and welding that are mature in the prior art. The mechanical parts and electrical equipment adopt conventional models in the prior art. The circuit connection adopts conventional connection methods in the prior art. The electrical equipment is connected to an external safe power source. These will not be described in detail here.

[0032] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0033] Obviously, the embodiments described above are only some embodiments of this utility model, not all embodiments. The accompanying drawings show preferred embodiments of this utility model, but do not limit the patent scope of this utility model. This utility model can be implemented in many different forms; conversely, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this utility model.

Claims

1. A rare earth rotary kiln insulation structure, characterized in that, It includes a kiln body steel shell (1), an inner layer insulation component (2) is provided on the inner surface of the kiln body steel shell (1), and an outer layer insulation component (3) is provided on the outer surface of the kiln body steel shell (1). The inner insulation component (2) includes a first heat insulation layer (4) disposed on the inner surface of the kiln body steel shell (1), a composite reflective layer (5) disposed on the inner surface of the first heat insulation layer (4), and a working layer (6) disposed on the inner surface of the composite reflective layer (5).

2. The rare earth rotary kiln insulation structure according to claim 1, characterized in that, The outer insulation component (3) includes a second heat insulation layer (9) disposed on the outer surface of the kiln body steel shell (1), an aerogel felt layer (8) disposed on the outer surface of the second heat insulation layer (9), a microporous calcium silicate board layer (7) disposed on the outer surface of the aerogel felt layer (8), and a stainless steel corrugated plate protective shell (10) disposed on the outer surface of the microporous calcium silicate board layer (7).

3. The rare earth rotary kiln insulation structure according to claim 2, characterized in that, The stainless steel corrugated plate protective shell (10) is provided with a number of T-shaped anchor nails (11). The T-shaped anchor nails (11) pass through the stainless steel corrugated plate protective shell (10), the microporous calcium silicate plate layer (7), the aerogel felt layer (8) and the second heat insulation layer (9) in sequence and are then welded and fixed to the kiln body steel shell (1).

4. The rare earth rotary kiln insulation structure according to claim 1, characterized in that, The working layer (6) is a lightweight mullite castable layer poured into the inner wall of the kiln steel shell (1), and the thickness of the working layer (6) is 80-150mm.

5. The rare earth rotary kiln insulation structure according to claim 1, characterized in that, The first heat insulation layer (4) is a nanoporous heat insulation board, and the thickness of the first heat insulation layer (4) is 20-40mm.

6. The rare earth rotary kiln insulation structure according to claim 1, characterized in that, The composite reflective layer (5) includes at least two layers of mirror stainless steel foil (12) and ceramic fiber paper (13) located between adjacent mirror stainless steel foils (12), wherein the mirror stainless steel foil (12) and ceramic fiber paper (13) are alternately stacked.

7. The rare earth rotary kiln insulation structure according to claim 6, characterized in that, The thickness of the mirror stainless steel foil (12) is 0.05-0.15mm, the thickness of the ceramic fiber paper (13) is 0.5-1.0mm, and the total number of layers of the composite reflective layer (5) is 4-8.

8. The rare earth rotary kiln insulation structure according to claim 2, characterized in that, The material of the second heat insulation layer (9) is a ceramic heat insulation board.

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