A rotary kiln for recycling waste heat of red mud material thermal reaction

Abstract

The application discloses a rotary kiln for heat reaction of red mud material and recycling of waste heat, which is characterized by comprising an inner cylinder with a feeding port and a discharging port, an outer cylinder, a combustion machine with a fire outlet, a power device, a material lifting plate, a heat conducting pipe and a smoke outlet; the material lifting plate is connected to the inner wall of the inner cylinder; the power device is connected to the inner cylinder and can drive the inner cylinder to rotate along the axis of the inner cylinder; the inner cylinder is located in the outer cylinder, and an annular cavity is formed between the outer cylinder and the inner cylinder; the fire outlet of the combustion machine is connected to the outer cylinder and extends into the annular cavity; the heat conducting pipe is connected to the inner wall of the inner cylinder at both ends and extends into the annular cavity; and the smoke outlet is located on the wall of the outer cylinder and communicates with the annular cavity. The application realizes external flame heating without pollution of the reactants and has high heat energy utilization rate.

Description

Technical Field

[0001] This invention relates to the field of thermal reaction technology, and in particular to a rotary kiln for recycling waste heat in the thermal reaction of red mud. Background Technology

[0002] Red mud is a tailings produced during aluminum production. Its mineral composition is relatively complex, mainly containing minerals such as Al2O3, Fe2O3, and SiO2. It typically exhibits strong alkalinity and corrosiveness. On average, 1.0-2.0 tons of red mud are generated as a byproduct of the production of 1 ton of alumina.

[0003] Red mud is rich in iron, aluminum, calcium, silicon, titanium, sodium, nickel, manganese, chromium, vanadium, as well as scandium, yttrium, and lanthanide rare earth elements. Through comprehensive development and utilization, it can be transformed from waste into treasure and from harm into benefit. Especially under the condition of increasingly scarce mineral resources, the recovery of valuable metals from red mud is becoming increasingly important. How to develop and utilize this enormous amount of red mud that has been dormant for many years, and truly achieve modern production with "zero tailings, zero waste, and zero secondary pollution," thereby promoting the comprehensive management of the mining environment, is an important issue of common concern to my country and countries around the world. Therefore, the development and utilization of red mud has very important practical significance.

[0004] Current technology primarily involves reducing iron oxide in red mud to magnetic magnetite (Fe3O4) through a high-temperature reduction reaction, followed by separation using a magnetic separator to obtain magnetic refined iron powder. However, existing processes place red mud and reactants in a rotary kiln, internally heating them with a flame generated by a burner. While this heating method has high thermal efficiency, existing burners typically use pulverized coal as fuel. The combustion process generates flue gas containing sulfur dioxide and nitrogen dioxide, which, upon contact with the ore in the red mud, produces sulfur and nitrogen compounds. This increases the difficulty of subsequent separation of various ore components and reduces the recovery rate of metal ore.

[0005] Therefore, there is a need for a thermal reaction device that can be used for red mud thermal reaction, avoids flue gas pollution of red mud ore, and has high thermal energy utilization rate. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a rotary kiln for recycling waste heat from the thermal reaction of red mud.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A rotary kiln for recycling waste heat from the thermal reaction of red mud materials, characterized in that it comprises:

[0009] An inner cylinder with a feed inlet and a discharge outlet;

[0010] outer cylinder;

[0011] A burner with an exhaust end;

[0012] A heat pipe with an air inlet and an air outlet;

[0013] The outer cylinder is equipped with a smoke exhaust port and a power unit.

[0014] The inner wall of the inner cylinder is provided with lifting plates;

[0015] The power unit can drive the inner cylinder to rotate along the axis of the inner cylinder.

[0016] The inner cylinder is located inside the outer cylinder, and there is an annular cavity between the outer cylinder and the inner cylinder;

[0017] The burner's outlet end is connected to the outer cylinder and extends into the annular cavity;

[0018] The heat pipe is disposed inside the inner cylinder, and the air inlet and air outlet penetrate the inner wall of the inner cylinder.

[0019] The exhaust port is located on the outer cylinder wall and communicates with the annular cavity.

[0020] Preferably, the exhaust port is located at one end of the outer cylinder near the feed port;

[0021] The heat-conducting pipe is inclinedly disposed inside the inner cylinder, and the air outlet end of the heat-conducting pipe is inclined toward the smoke exhaust port.

[0022] Preferably, the material layer is located on the side wall at the bottom of the inner cylinder, in the area between n / 3 of the inner cylinder diameter and the direction perpendicular to the length of the inner cylinder, where n is greater than or equal to 1 and less than or equal to 2.

[0023] The two ends at the top of the filling layer that contact the inner cylinder are the first end and the second end, respectively;

[0024] The burner's outlet end is positioned facing either the first or second end of the charging layer;

[0025] The inner cylinder has a first rotation direction. When the inner cylinder rotates in the first rotation direction, the first end or the second end facing the fire outlet moves closer to the bottom of the material layer.

[0026] Preferably, the inner cylinder consists of a preheating section and a high-temperature section from the end where the feed inlet is located to the end where the discharge outlet is located, and the length of the high-temperature section is greater than the length of the preheating section;

[0027] The preheating section and the high-temperature section are each equipped with heat-conducting pipes.

[0028] Preferably, the inner wall of the outer cylinder is provided with refractory material.

[0029] Preferably, the rotary kiln for recycling waste heat from the thermal reaction of red mud material is characterized in that,

[0030] Also includes: placeholder columns;

[0031] The placeholder post is disposed inside the heat pipe, and a cavity is formed between the outer surface of the placeholder post and the inner wall of the heat pipe.

[0032] Preferably, there is an air-collecting space between the air inlet end and the end of the occupant column near the air inlet end.

[0033] Preferably, the length of the air collection space in the length direction of the occupant column is greater than 10cm.

[0034] Preferably, a heat conductor is provided between the heat pipe and the occupant post, with one end of the heat conductor connected to the heat pipe and the other end connected to the occupant post.

[0035] Preferably, the cross-section of the outer wall of the heat pipe has a pointed tip, and the distance between the two sides of the cross-section connected to the pointed tip gradually increases in the direction away from the pointed tip;

[0036] The tip is directed toward the end where the feed inlet is located.

[0037] Preferably, the rotary kiln for recycling waste heat from the thermal reaction of red mud material is characterized by further comprising:

[0038] A baffle plate with a concave wall surface;

[0039] The air vent is connected to the air inlet end of the heat pipe, and the orientation of the concave wall surface is the same as the rotation direction of the inner cylinder.

[0040] Preferably, any of the horizontal spiral propulsion thermal reaction devices is characterized by further comprising:

[0041] Smoke collection chamber; the smoke collection chamber is connected to the smoke exhaust port.

[0042] The beneficial effects of this invention are reflected in:

[0043] This invention provides a horizontal spiral propulsion thermal reaction device for flame-insulated heat treatment of materials. This effectively prevents sulfur- and nitrogen-containing flue gas generated during combustion from contacting the materials during heating, thus preventing contamination and the formation of sulfur- and nitrogen-containing compound impurities. This makes it easier to separate various metals in the subsequent red mud ore, improving the ore recovery rate. At the same time, by setting the heat-conducting pipe and the position of the burner outlet, the heat utilization rate of the flue gas is effectively increased, improving the heating efficiency. Furthermore, by setting the pointed outer wall of the heat-conducting pipe, the ore is dispersed, and the distance the ore flows over the outer wall of the heat-conducting pipe is increased, thereby increasing the heat absorbed by the ore from the heat-conducting pipe and improving the heating efficiency. Attached Figure Description

[0044] Figure 1 This is a three-dimensional rotary kiln structure for recycling waste heat from the thermal reaction of red mud materials.

[0045] Figure 2 A cross-sectional view of the inner cylinder of a rotary kiln for recycling waste heat from the thermal reaction of red mud materials.

[0046] Figure 3 A side view of a rotary kiln for recycling waste heat from the thermal reaction of red mud materials;

[0047] Figure 4 This is a side view of a rotary kiln after loading, which is used for waste heat recycling in the thermal reaction of red mud.

[0048] Figure 5 A partial cross-sectional view of a rotary kiln for recycling waste heat from the thermal reaction of red mud materials;

[0049] Figure 6 This is a cross-sectional view of the heat pipe;

[0050] Figure 7 A schematic diagram of the heat pipe structure connecting the air vent.

[0051] Figure 8 This is a cross-sectional view after the heat pipe is connected to the inner cylinder.

[0052] Figure 9 This is a top view of the heat pipe.

[0053] Figure description: Inner cylinder 1, feed inlet 101, discharge outlet 102, outer cylinder 2, exhaust outlet 201, power unit 202, burner 3, flame outlet 301, heat pipe 4, air inlet 401, air outlet 402, lifting plate 103, annular cavity 104; material layer 105, first end 1051, second end 1052; occupier column 403; air collection space 404; heat conductor 405; tip 406; wind deflector 407. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0055] Please see Figure 1-8 As shown, the specific embodiments provided by the present invention are as follows:

[0056] Example 1

[0057] A rotary kiln for recycling waste heat from the thermal reaction of red mud materials, characterized in that it comprises:

[0058] The inner cylinder 1 has an inlet 101 and an outlet 102;

[0059] Outer cylinder 2;

[0060] A burner 3 having an outlet end 301;

[0061] A heat pipe 4 having an air inlet 401 and an air outlet 402;

[0062] The outer cylinder 2 is provided with a smoke exhaust port 201 and a power unit 202.

[0063] The inner wall of the inner cylinder 1 is provided with a lifting plate 103;

[0064] The power unit 202 can drive the inner cylinder 1 to rotate along the axis of the inner cylinder 1;

[0065] The inner cylinder 1 is located inside the outer cylinder 2, and there is an annular cavity 104 between the outer cylinder 2 and the inner cylinder 1;

[0066] The burner 3's outlet end 301 is connected to the outer cylinder 2 and extends into the annular cavity 104;

[0067] The heat pipe 4 is disposed inside the inner cylinder 1, and the air inlet 401 and the air outlet 402 penetrate the inner wall of the inner cylinder 1.

[0068] The exhaust port 201 is located on the wall of the outer cylinder 2 and is connected to the annular cavity 104.

[0069] The current heating method for rotary kilns is usually internal heating, where the flame generated by the burner is directly injected into the kiln to heat the reactants. This causes gases such as sulfur dioxide and nitrogen dioxide produced after fuel combustion to come into contact with the reactants, causing pollution and resulting in the final reaction not achieving the expected results. To avoid this situation, external heating is required to bring the reactants to the target temperature. However, external heating has low heat conversion efficiency, requires more fuel to reach the target temperature, and takes longer to heat the reactants.

[0070] This embodiment provides a rotary kiln consisting of an inner cylinder 1 and an outer cylinder 2, which are movably connected by bearings. An annular cavity 104 is formed between the inner and outer cylinders 2. A burner 3 has its outlet end 301 extending from the outer cylinder 2 into the annular cavity 104. When heating of the reactants inside the kiln is required, the flame generated by the burner 3 is injected into the annular cavity 104 to heat the inner cylinder 1. The inner cylinder 1 heats the reactants to the required temperature through heat transfer. Simultaneously, the inner cylinder 1 is driven by a power unit 202 to rotate along its axis. The lifting plate 103 drives the reactants to rotate. During installation, the end of the device with the feed inlet 101 is positioned higher than the end with the discharge outlet 102, causing the reactants to move towards the discharge outlet 102 under gravity. Meanwhile, the flue gas generated by fuel combustion flows along the annular cavity 104 and enters the heat pipe 4, transferring heat to its wall. The heat pipe 4 then contacts the reactants in the inner cylinder 1, further absorbing heat from the flue gas. This results in high heat utilization and effectively prevents the flue gas from contaminating the reactants. In actual rotary kiln manufacturing, connecting holes can be made on the inner cylinder 1. The two ends of the heat pipe 4 can be welded to these connecting holes, creating a seal between the heat pipe 4 and the connecting holes to prevent flue gas from entering.

[0071] Another scenario involves red mud requiring multiple material extractions to achieve harmless treatment (no harmful substance emissions), resulting in a lengthy process. This lengthy process is subject to uncertainties such as manual intervention and shift changes during 24 / 7 operation. Consequently, different shifts and batches of materials processed using the same method may produce inconsistent outputs. This poses a challenge to mass production standardization. The embodiments of this application employ flame-heated outer cylinders. This avoids the involvement of combustion gases in the reaction, improving the thermal reaction temperature and heat supply. Furthermore, it provides more efficient and effective adjustability compared to preheating media. This adjustment occurs under different material batches and shift changes, ensuring effective production of this process. For example, the moisture content of the inlet material varies and may change multiple times within a day. Heating at the same temperature during the thermal reaction could lead to material caking, severely impacting the thermal reaction effect.

[0072] Preferably, the exhaust port 201 is located at one end of the outer cylinder 2 near the feed port 101;

[0073] The heat pipe 4 is inclinedly disposed inside the inner cylinder 1, and the air outlet 402 of the heat pipe 4 is inclined toward the exhaust port 201.

[0074] In this embodiment, the heat-conducting pipe 4 is inclinedly disposed inside the inner cylinder 1, with the air outlet 402 of the heat-conducting pipe 4 inclined toward the exhaust port 201. This further increases the length of the heat-conducting pipe 4 in the inner cylinder 1 and increases the wall area of ​​a single heat-conducting pipe 4 in the inner cylinder 1. Because the feed end of the rotary kiln is higher than the discharge end, the flue gas generated by combustion will converge toward the feed end. This realizes that after the flue gas is generated, heat is transferred to the reactants through the heat-conducting pipe 4, and the heat is reused before being discharged from the rotary kiln. This effectively improves the heat transfer amount of a single heat-conducting pipe 4 per unit time.

[0075] Example 2

[0076] In this embodiment, as a further improvement to the technical solution of Embodiment 1, the feature is that,

[0077] The area between the bottom side wall of the inner cylinder 1 and n / 3 of the inner cylinder diameter along the direction perpendicular to the length of the inner cylinder 1 is the material layer 105, where n is greater than or equal to 1 and less than or equal to 2.

[0078] The top two ends of the material layer 105 that contact the inner cylinder 1 are the first end 1051 and the second end 1052, respectively.

[0079] The burner 3's outlet end 301 is positioned toward the first end 1051 or the second end 1052 of the charging layer 105;

[0080] The inner cylinder 1 has a first rotation direction. When the inner cylinder 1 rotates in the first rotation direction, the first end 1051 or the second end 1052 of the fire outlet 301 moves closer to the bottom of the material layer 105.

[0081] The inventors discovered that during the actual heating process of the rotary kiln, the flame emitted by the burner 3 first heats the contact area between the inner cylinder 1 of the rotary kiln and the flame. After the temperature of this area rises, it gradually rotates and comes into contact with the material inside the inner cylinder 1 before heat conduction occurs through contact. If the contact area between the inner cylinder 1 of the rotary kiln and the flame is too far from the material, the contact area needs to rotate a certain distance after being heated before it can come into contact with the material. During this rotation period, the heat at the contact area will gradually be lost, resulting in a waste of heat energy. If the contact area between the inner cylinder 1 of the rotary kiln and the flame is within the area where the material is located, the contact area between the inner cylinder 1 and the flame will only come into contact with a portion of the material area after being heated and rotated by the flame, and then will detach from the material area, also resulting in a waste of heat energy.

[0082] In this embodiment, the area at any height between 1 / 3 and 2 / 3 of the diameter of the inner cylinder 1 from the bottom of the inner cylinder 1 in the vertical direction is the charging layer 105. That is, after the rotary kiln inner cylinder 1 is filled with material, the height of the material area is between 1 / 3 and 2 / 3 of the diameter of the inner cylinder 1. At the same time, the flame outlet 301 of the burner 3 is set towards the first end 1051 or the second end 1052 of the charging layer 105. The first end 1051 and the second end 1052 are located at the two ends of the top of the charging layer 105 that are in contact with the inner cylinder 1. When the inner cylinder 1 rotates in the first rotation direction, the first end 1051 or the second end 1052 of the burner 3's flame outlet 301 moves closer to the bottom of the charging layer 105. This achieves that the contact part between the inner cylinder 1 and the flame is heated by the flame sprayed by the burner 3 and then contacts the area where the material is located. The material rotates completely around the area where the material is located before leaving the area where the material is located, which greatly improves the thermal energy utilization rate of the rotary kiln.

[0083] Example 3

[0084] In this embodiment, as a further improvement to the technical solution of Embodiment 1, the feature is that,

[0085] The inner cylinder 1 consists of a preheating section and a high-temperature section from the end where the feed inlet 101 is located to the end where the discharge outlet 102 is located, and the length of the high-temperature section is greater than the length of the preheating section.

[0086] The preheating section and the high-temperature section are each equipped with a heat pipe 4.

[0087] Considering that the heat treatment of red mud includes a preheating stage and a high-temperature reduction stage, this embodiment divides the inner cylinder 1 into a preheating section and a high-temperature section, so that the temperature inside the cylinder in the preheating section can reach 600-1000 degrees Celsius, and the temperature inside the cylinder in the high-temperature section can reach 1200-1400 degrees Celsius, ensuring that the temperature of the red mud ore can reach above 600 degrees Celsius in the preheating stage and above 1200 degrees Celsius in the high-temperature reduction stage.

[0088] By setting a preheating section and a high-temperature section, the temperature of the preheating section can be set within a large adjustable range (400 degrees Celsius between high and low temperatures). This allows for adaptive adjustments to materials of different batches and parameters, avoiding problems such as material caking or insufficient heating under the same temperature parameters. This ensures uniform heating of the material and rapid and uniform evaporation of moisture, providing a uniformly heated, fully dispersed material that is easy to mix and turn over for the subsequent high-temperature thermal reaction.

[0089] Meanwhile, heat pipes 4 are respectively installed in the preheating section and the high-temperature section, so that the flue gas outside the inner cylinder 1 of the preheating section enters the heat pipe 4 of the high-temperature section to realize the secondary utilization of heat energy before entering the inner cylinder 1 of the preheating section. This avoids the flue gas with a higher temperature entering the heat pipe 4 of the inner cylinder 1 of the preheating section, which would cause the heating temperature of the preheating section to be too high.

[0090] Preferably, the inner wall of the outer cylinder 2 is provided with refractory material.

[0091] Considering that the reactor cylinder is typically made of metal with high thermal conductivity, when the flame generated by the burner 3 enters the annular cavity 104, the outer cylinder 2 will also absorb heat. Since the reactor only needs the inner cylinder 1 to absorb heat and transfer it to the reactants, direct contact between the outer cylinder 2 and the flame would lead to energy waste, and excessively high temperatures in the outer cylinder 2 could also pose safety hazards. Therefore, in this embodiment, a layer of refractory material is provided on the inner side of the outer cylinder 2, effectively reducing heat transfer to the outer cylinder 2, lowering energy loss during the heating process of the reactor, and improving the safety of the reactor. In some embodiments, fiber modules are used as the refractory material. Fiber modules are chosen as the refractory material because they have low thermal conductivity and heat capacity, significant insulation and energy-saving effects, and low density, which greatly reduces the load on the steel structure of the device during actual installation, reduces the amount of steel used, and lowers engineering costs to some extent.

[0092] Example 4

[0093] In this embodiment, as a further improvement to the technical solution of Embodiment 1, the feature is that,

[0094] Also includes: placeholder column 403;

[0095] The placeholder post 403 is disposed inside the heat pipe 4, and a cavity is formed between the outer surface of the placeholder post 403 and the inner wall of the heat pipe 4.

[0096] The inventors discovered that after the flue gas enters the heat pipe 4, only the part of the flue gas near the inner wall of the heat pipe 4 comes into contact with the heat pipe 4, and the flue gas transfers heat to the heat pipe 4 at a relatively fast speed. However, the flue gas located in the middle part of the heat pipe 4 can only transfer heat to the surrounding flue gas through the gas-to-gas transfer. The heat transfer efficiency between the gas-to-gas transfer is low, that is, the heat utilization efficiency of the flue gas in the middle part is low.

[0097] Therefore, in this embodiment, a placeholder post 403 is provided in the heat pipe 4. A cavity is formed between the outer surface of the placeholder post 403 and the inner wall of the heat pipe 4. After the flue gas enters the heat pipe 4, it will accumulate in the cavity between the placeholder post 403 and the heat pipe 4, so that the flue gas will not be in the center of the heat pipe, but will be in contact with the heat pipe 4, and the heat will be quickly transferred to the heat pipe 4, effectively improving the utilization rate of flue gas heat.

[0098] Example 5

[0099] In this embodiment, as a further improvement to the technical solution of Embodiment 4, the feature is that,

[0100] There is an air collection space 404 between the air inlet end 401 and the end of the occupant column 403 near the air inlet end 401.

[0101] Preferably, the length of the air collection space 404 in the longitudinal direction of the occupant column 403 is greater than 10cm.

[0102] The inventors discovered that, without changing the length of the heat pipe 4, the amount of flue gas entering the heat pipe 4 per unit time can be increased by increasing the diameter of the heat pipe 4. However, the occupant column 403 inside the heat pipe 4 will obstruct the entry of flue gas. Therefore, in this embodiment, an air collecting space 404 is provided between the air inlet end 401 of the heat pipe 4 and the end of the occupant column 403 near the air inlet end 401. The air collecting space 404 ensures that the occupant column 403 does not affect the entry of flue gas, and the flue gas enters the air collecting space 404 and then converges towards the inner wall of the heat pipe 4.

[0103] Example 6

[0104] In this embodiment, as a further improvement to the technical solution of Embodiment 5, the feature is that,

[0105] A heat conductor 405 is provided between the heat pipe 4 and the occupant post 403. One end of the heat conductor 405 is connected to the heat pipe 4, and the other end is connected to the occupant post 403.

[0106] The inventors discovered that after setting a placeholder post 403 in the heat pipe 4, the placeholder post 403 also absorbs heat from the flue gas. However, the heat from the placeholder post 403 is difficult to transfer to the heat pipe 4. Therefore, in this embodiment, a heat conductor 405 (which can be any one of a heat-conducting sheet, a heat-conducting post, or a heat-conducting block) is set between the heat pipe 4 and the placeholder post 403. The heat pipe 4 quickly absorbs the heat from the placeholder post 403 through the heat conductor 405. After the temperature of the placeholder post 403 drops, it absorbs heat from the flue gas again, further improving the thermal energy utilization efficiency.

[0107] Example 7

[0108] In this embodiment, as a further improvement to the technical solution of Embodiment 1, the feature is that,

[0109] The cross-section of the outer wall of the heat pipe 4 has a tip 406, and the distance between the two sides of the cross-section connected to the tip 406 gradually increases in the direction away from the tip 406.

[0110] The tip 406 is directed toward the end where the feed inlet 101 is located.

[0111] In this embodiment, the cross-section of the outer wall of the heat-conducting pipe 4 has a pointed tip 406, and the distance between the two sides connected to the pointed tip 406 on the cross-section gradually increases as it moves away from the pointed tip 406. The pointed tip 406 is oriented towards the end where the feed inlet 101 is located. In actual production, after the material enters the inner cylinder 1 of the rotary kiln from the feed inlet 101, it can fall to the pointed tip 406. Because the distance between the two sides connected to the pointed tip 406 gradually increases as it moves away from the pointed tip 406, the reactants that fall to the pointed tip 406 will slide past the two sides before leaving the heat-conducting pipe 4. This prolongs the residence time of the reactants on the outer wall of the heat-conducting pipe 4, increasing the heat absorbed by the reactants from the flue gas through the heat-conducting pipe 4.

[0112] Example 8

[0113] In this embodiment, as a further improvement to the technical solution of Embodiment 5, the feature is that,

[0114] Also includes:

[0115] A wind deflector 407 with a concave wall surface;

[0116] The air intake plate 407 is connected to the air inlet end 401 of the heat pipe 4, and the orientation of the concave wall surface is the same as the rotation direction of the inner cylinder 1.

[0117] During the actual installation of the rotary kiln, the height of the end where the feed inlet 101 is located needs to be higher than the height of the end where the discharge outlet 102 is located. The flue gas generated by the burner 3 will flow from the end where the discharge outlet 102 is located to the end where the feed inlet 101 is located. Therefore, the air inlet end 401 of the heat pipe 4 is close to the end where the discharge outlet 102 is located. In order to speed up the flow of flue gas entering the air inlet end 401 of the heat pipe 4, this embodiment provides a baffle plate 407 at the air inlet end 401 of the heat pipe 4. The baffle plate 407 has a concave wall surface. As the inner cylinder 1 rotates, the concave wall surface will push the flue gas into the heat pipe 4, increasing the flow speed of the flue gas in the heat pipe 4, that is, increasing the amount of flue gas entering the heat pipe 4 per unit time, and further improving the thermal energy utilization rate of the flue gas.

[0118] Example 9

[0119] In this embodiment, as a further improvement to the technical solutions of embodiments 1-8, it is characterized by further including:

[0120] The smoke collection chamber is connected to the smoke exhaust port 201.

[0121] In this embodiment, a smoke chamber is configured to communicate with the annular cavity 104, which can be used to contain the flue gas generated by the combustion. The flue gas can then be purified before being discharged, reducing pollution.

[0122] In some embodiments, an exhaust fan is provided at one end of the smoke chamber to remove the water vapor and flue gas generated by combustion, preventing the water vapor from lowering the reaction temperature in the annular cavity 104.

[0123] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "top", "bottom", "inner", "outer", "inner side", "outer side", etc. indicate the orientation or positional relationship.

[0124] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "assembly" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0125] In the description of embodiments of the present invention, specific features, structures, materials or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0126] In the description of the embodiments of the present invention, it should be understood that "-" and "~" represent a range of two values, and this range includes the endpoints. For example, "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0127] In the description of embodiments of the present invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0128] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rotary kiln for recycling waste heat from the thermal reaction of red mud materials, characterized in that, include: An inner cylinder with a feed inlet and a discharge outlet; outer cylinder; A burner with an exhaust end; A heat pipe with an air inlet and an air outlet; The outer cylinder is equipped with a smoke exhaust port and a power unit; The inner wall of the inner cylinder is provided with lifting plates; The power unit can drive the inner cylinder to rotate along the axis of the inner cylinder. The inner cylinder is located inside the outer cylinder, and there is an annular cavity between the outer cylinder and the inner cylinder; The firing end is connected to the outer cylinder and extends into the annular cavity; The heat pipe is disposed inside the inner cylinder, and the air inlet and air outlet penetrate the inner wall of the inner cylinder. The exhaust port is located on the outer cylinder wall and communicates with the annular cavity; The exhaust port is located at one end of the outer cylinder near the feed port; the heat pipe is inclined inside the inner cylinder, and the air outlet of the heat pipe is inclined toward the exhaust port.

2. The rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 1, characterized in that, The material layer is located on the side wall at the bottom of the inner cylinder, in the area between n / 3 of the inner cylinder diameter and the direction perpendicular to the length of the inner cylinder, where n is greater than or equal to 1 and less than or equal to 2. The two ends at the top of the filling layer that contact the inner cylinder are the first end and the second end, respectively; The burner's outlet end is positioned facing either the first or second end of the charging layer; The inner cylinder has a first rotation direction. When the inner cylinder rotates in the first rotation direction, the first end or the second end facing the fire outlet moves closer to the bottom of the material layer.

3. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 1, characterized in that, The inner cylinder consists of a preheating section and a high-temperature section from the end where the feed inlet is located to the end where the discharge outlet is located, and the length of the high-temperature section is greater than the length of the preheating section. The preheating section and the high-temperature section are each equipped with heat-conducting pipes.

4. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 1, characterized in that, Also includes: Placeholder column; The placeholder post is disposed inside the heat pipe, and a cavity is formed between the outer surface of the placeholder post and the inner wall of the heat pipe.

5. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 4, characterized in that, There is an air collection space between the air inlet end and the end of the occupant column near the air inlet end.

6. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 5, characterized in that, The length of the air collection space in the longitudinal direction of the occupant column is greater than 10cm.

7. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 6, characterized in that, A heat conductor is provided between the heat pipe and the occupant post, with one end of the heat conductor connected to the heat pipe and the other end connected to the occupant post.

8. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 1, characterized in that, The cross-section of the outer wall of the heat pipe has a pointed tip, and the distance between the two sides of the cross-section connected to the pointed tip gradually increases in the direction away from the pointed tip. The tip is directed toward the end where the feed inlet is located.

9. A rotary kiln for waste heat recycling in the thermal reaction of red mud material according to claim 1, characterized in that, Also includes: A baffle plate with a concave wall surface; The air vent is connected to the air inlet end of the heat pipe, and the orientation of the concave wall surface is the same as the rotation direction of the inner cylinder.

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