Calcining furnace for preparing sodium carbonate from waste sodium sulfate

Abstract

The invention relates to the technical field of calcining furnaces, and provides a calcining furnace for preparing sodium carbonate from waste sodium sulfate, the calcining furnace comprises a rack and a furnace body, the furnace body comprises an inner cylinder, an outer cylinder and an end cover, the inner cylinder and the outer cylinder are coaxially nested and rotatably arranged on the rack, the inner cylinder and the outer cylinder are conical, and the large-diameter ends of the inner cylinder and the outer cylinder face opposite directions so as to jointly form a broken-line-shaped conveying channel. The broken-line-shaped material conveying path enables the motion trail of materials in the furnace to be prolonged, on the premise that the heating distance and the standing time of the materials are guaranteed, compared with a traditional linear rotary calcining furnace, the length of a furnace body is greatly shortened, the occupied area is reduced, and the requirement for the area of a production site is lowered. By means of the technical scheme, the technical problems that in the prior art, in order to guarantee the calcining time of raw materials, a traditional rotary calcining furnace needs enough length, and the occupied area is large are solved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of calcination furnace technology, specifically, to a calcination furnace for producing soda ash from waste sodium sulfate. Background Technology

[0002] In the chemical industry, waste treatment and resource recycling have always been important research directions. Waste sodium sulfate, due to its inherent characteristics, has relatively small market demand and low value; improper handling can also pose a pollution hazard to the environment. To solve this problem, processing waste sodium sulfate to produce soda ash is a feasible approach. Soda ash, as an important basic inorganic chemical raw material, is widely used in many industries such as glass manufacturing, chemicals, metallurgy, and textiles, and has high utilization value.

[0003] In current production processes, sodium bicarbonate is produced after the waste sodium sulfate is treated. After sodium bicarbonate crystallizes from the reaction solution, most of the mother liquor is separated by a centrifuge. However, moisture remains on the crystal surface, forming a wet material. This wet material needs to be treated at high temperature in a calcining furnace to obtain the final soda ash. Rotary calcining furnaces are widely used in the calcination process of wet sodium bicarbonate. By continuously rotating, the rotary calcining furnace keeps the raw material tumbling inside, achieving a more uniform heating effect, and finally discharging the calcined product.

[0004] To ensure that the wet sodium bicarbonate feedstock achieves the desired calcination effect, the rotary kiln needs to be long enough to provide sufficient residence time for the raw material within the furnace, ensuring uniform heating and a complete calcination reaction. However, a longer rotary kiln results in a larger footprint, requiring a larger production area and making its layout susceptible to space constraints.

[0005] Therefore, developing a calcining furnace for producing soda ash from waste sodium sulfate that can both ensure ideal calcination results and effectively reduce the footprint has become an important issue that the chemical industry urgently needs to address, and is of great significance for promoting the resource utilization of waste sodium sulfate. Summary of the Invention

[0006] To overcome the above-mentioned defects, embodiments of the present invention provide a calcining furnace for producing soda ash from waste sodium sulfate, which solves the technical problem in the related art that traditional rotary calcining furnaces require sufficient length and occupy a large area in order to ensure the calcination time of raw materials.

[0007] According to one aspect, at least one embodiment of the present invention provides a calcining furnace for producing soda ash from waste sodium sulfate, comprising a frame and a furnace body. The furnace body includes an inner cylinder, an outer cylinder, and end caps. The inner cylinder and the outer cylinder are connected and coaxially nested, and rotatably mounted on the frame. Both the inner cylinder and the outer cylinder are conical, and their large-diameter ends face opposite directions. There are two end caps mounted on the frame, and the two end caps are respectively used to seal both ends of the outer cylinder. The end caps are rotatably engaged with the ends of the outer cylinder. The small-diameter end of the inner cylinder passes through the end cap of the large-diameter end of the outer cylinder, which is used to allow material to enter and guide the material to the small-diameter end of the outer cylinder. The outer cylinder can receive the material in the inner cylinder and guide the material to move towards the large-diameter end. The end cap of the large-diameter end of the outer cylinder has a discharge port.

[0008] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: A mounting frame is rotatably mounted inside the furnace body. The mounting frame has an inner support extending into the inner cylinder and an outer support extending between the inner cylinder and the outer cylinder. Both the inner support and the outer support have multiple spiral plates. The spiral plates on the inner support are in contact with the inner wall of the inner cylinder, and the spiral plates on the outer support are in contact with the inner wall of the outer cylinder. The furnace body is provided with locking elements for locking the mounting frame and the outer cylinder, or locking the mounting frame and the end cover.

[0009] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: The mounting bracket has a rotating state and a stationary state; When the mounting frame is in a rotating state, the locking element is used to lock the mounting frame and the outer cylinder. The mounting frame can rotate synchronously with the outer cylinder to intermittently lift the material with the help of the spiral plate. When the mounting bracket is stationary, the locking element is used to lock the mounting bracket and the end cap. The mounting bracket can scrape off the material on the inner wall of the outer cylinder and the inner cylinder by means of the spiral plate when the outer cylinder rotates.

[0010] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: The frame is provided with a mounting box located at the large diameter end of the outer cylinder. One side of the mounting box has a heating port for connecting the burner. The mounting box is provided with a feed hopper that penetrates the top wall of the mounting box. The bottom of the feed hopper is connected to the small diameter end of the inner cylinder. The bottom of the mounting box has a discharge port that is connected to the discharge port.

[0011] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: The installation box has a conical heat collection hood, which is located below the feed hopper and lower than the heating port. It is used to collect the waste heat gas flow discharged from the discharge port. The feed hopper is equipped with a heat transfer tube, which has multiple heat dissipation holes on its peripheral wall. The heat transfer tube penetrates the bottom wall of the feed hopper and communicates with the area below the heat collection hood. The heat transfer tube can dissipate the waste heat gas collected by the heat collection hood through the heat dissipation hole into the feed hopper to pre-dry the material in the feed hopper.

[0012] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: A fixed plate is fitted around the heat transfer tube, and the fixed plate is provided with a plurality of first material leakage holes. A rotating frame is rotatably installed inside the feed hopper, and a rotating plate is rotatably fitted around the heat transfer tube and located below the fixed plate on the rotating frame. The rotating plate is provided with a plurality of second material leakage holes. After the rotating disk rotates, it can intermittently connect the second discharge hole and the first discharge hole to allow for intermittent material discharge.

[0013] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: Both the fixed disk and the rotating disk are cone-shaped with their openings facing downwards. The fixed disk allows the material to flow away from the heat transfer tube.

[0014] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: The rotating frame is provided with a gear ring, which is located on the outer periphery of the feed hopper. A gear is rotatably provided on the outer side of the feed hopper to mesh with the gear ring and drive the gear ring to rotate.

[0015] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: The fixed disk and the heat transfer tube, as well as the rotating disk and the rotating frame, can be detachably connected.

[0016] For example, in at least one embodiment of the present invention, a calcining furnace for producing soda ash from waste sodium sulfate further includes: The mounting bracket has a mandrel that passes through the end cover at its center, and the end of the mandrel has a handle.

[0017] The beneficial effects of the embodiments of the present invention are as follows: In this invention, the coaxial nesting of the inner and outer cylinders with their large-diameter ends facing opposite directions creates a zigzag-shaped material conveying channel. When wet sodium bicarbonate enters from the small-diameter end of the inner cylinder, it tumbles within the inner cylinder and is conveyed forward along its tapered direction as the inner cylinder rotates. Due to the rotation of the inner cylinder, the material continuously comes into contact with hot air during forward conveying. After leaving the inner cylinder, the material falls into the outer cylinder. At this point, because the large-diameter ends of the outer and inner cylinders face opposite directions, the material's movement direction changes within the outer cylinder, and it begins to be conveyed backward along the tapered direction of the outer cylinder, continuing its tumbling and heating. This zigzag-shaped material conveying path extends the material's trajectory within the furnace. While ensuring the heating distance and residence time, it significantly shortens the furnace length compared to traditional linear rotary calcining furnaces, reducing the floor space required and lowering the requirements for production area.

[0018] Furthermore, in traditional rotary kilns, the burners are typically located at one end. However, due to their considerable length, heat loss is inevitable as heat is transferred to the side furthest from the burners. In this embodiment, because the furnace body is shorter and the overall volume is more compact, the distance the heat needs to be transferred is reduced, thus decreasing heat loss accordingly. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of the present invention and these drawings without any creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a calcining furnace for producing soda ash from waste sodium sulfate in one embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the internal structure of a calcining furnace for producing soda ash from waste sodium sulfate in one embodiment; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 1 A schematic diagram of the heat transfer tube and rotating frame installation state in the embodiment; Figure 5 for Figure 1 A schematic diagram of the structure of the heat transfer tube and the rotating frame in the disassembled state in the embodiment; Figure 6 for Figure 1 A schematic diagram of the internal structure of the furnace body in the embodiment; Figure 7for Figure 6 Enlarged view at point B in the middle; Figure 8 for Figure 1 A schematic diagram of the structure of the inner cylinder, outer cylinder and end cap in the embodiment; Figure 9 for Figure 1 A schematic diagram of the structure of the external support in the embodiment; Figure 10 for Figure 1 The schematic diagram of the internal support structure in the embodiment is shown.

[0021] In the diagram: 1. Frame, 2. Furnace body, 3. Inner cylinder, 4. Outer cylinder, 5. End cover, 6. Material conveying channel, 7. Discharge port, 8. Mounting frame, 9. Inner support, 10. Outer support, 11. Spiral plate, 12. Mounting box, 13. Feed hopper, 14. Discharge port, 15. Heating port, 16. Heat collection cover, 17. Heat transfer tube, 18. Heat dissipation hole, 19. Fixed plate, 20. First material leakage hole, 21. Rotating frame, 22. Rotating plate, 23. Second material leakage hole, 24. Gear ring, 25. Gear, 26. Handle. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0023] To keep the drawings concise, each drawing only schematically shows the parts relevant to the invention; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0024] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections 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 this invention based on the specific circumstances.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0027] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] like Figures 1-10 The diagram illustrates a calcining furnace for producing soda ash from waste sodium sulfate according to an embodiment of the present invention. The furnace includes a frame 1 and a furnace body 2. The furnace body 2 includes an inner cylinder 3, an outer cylinder 4, and end caps 5. The inner cylinder 3 and outer cylinder 4 are coaxially nested and rotatably mounted on the frame 1. Both the inner cylinder 3 and outer cylinder 4 are conical, with their large-diameter ends facing opposite directions to form a zigzag material conveying channel 6. Two end caps 5 are installed on the frame 1 and rotatably connected to both ends of the outer cylinder 4, serving to seal both ends of the furnace body 2 and prevent heat loss. A discharge port 7 is provided on the end cap 5 located on the large-diameter end of the outer cylinder 4, through which the soda ash obtained after calcination in the inner cylinder 3 and outer cylinder 4 is discharged.

[0029] Working Principle: The coaxial nesting of the inner cylinder 3 and outer cylinder 4, with their large-diameter ends facing opposite directions, forms a zigzag conveying channel 6. When wet sodium bicarbonate enters from the small-diameter end of the inner cylinder 3, it tumbles within the inner cylinder 3 and is conveyed forward along its tapered direction as the inner cylinder 3 rotates. Due to the rotation of the inner cylinder 3, the material continuously comes into contact with hot air during forward conveying. When the material detaches from the inner cylinder 3, it falls into the outer cylinder 4. At this point, because the large-diameter ends of the outer cylinder 4 and the inner cylinder 3 face opposite directions, the material's movement direction within the outer cylinder 4 changes, and it begins to be conveyed backward along the tapered direction of the outer cylinder 4, continuing to tumble and heat. This zigzag conveying path extends the material's trajectory within the furnace, significantly shortening the furnace body 2 compared to traditional linear rotary calcining furnaces while ensuring sufficient heating distance and residence time. This reduces the floor space required and lowers the requirements for production area.

[0030] Furthermore, in traditional rotary kilns, the burner is typically located at one end. However, due to its considerable length, heat loss is inevitable as heat is transferred to the side furthest from the burner. In this embodiment, because the length of the furnace body 2 is reduced, the overall volume is more compact, thus shortening the distance heat needs to be transferred and consequently reducing heat loss.

[0031] In some examples, such as Figure 2 , Figures 6-10 As shown, the mounting frame 8 is located inside the furnace body 2 and is rotatable. The mounting frame 8 is equipped with an inner support 9 and an outer support 10. The inner support 9 is located inside the inner cylinder 3, and the outer support 10 is located in the interlayer between the outer cylinder 4 and the inner cylinder 3. Both the inner support 9 and the outer support 10 have multiple spiral plates 11 arranged along the spiral direction. The two sets of spiral plates 11 are respectively attached to the inner walls of the inner cylinder 3 and the outer cylinder 4.

[0032] The mounting bracket 8 has a rotating state and a stationary state. To achieve different working states of the mounting bracket 8, a locking structure is designed. Through holes for inserting locking components are provided on the outer cylinder 4 and the end cap 5, respectively. Locking holes are designed on the mounting bracket 8 at positions corresponding to the through holes on the outer cylinder 4 and the end cap 5. Locking components can be locking pins or locking bolts, etc. When it is necessary to lock the mounting bracket 8 to the outer cylinder 4, the locking component is inserted into the through hole on the outer cylinder 4 and then into the corresponding locking hole on the mounting bracket 8, allowing the mounting bracket 8 to rotate with the inner cylinder 3 and the outer cylinder 4. When it is necessary to lock the mounting bracket 8 to the end cap 5, the locking to the outer cylinder 4 is released, the locking component is inserted into the through hole on the end cap 5 and then into the corresponding locking hole on the mounting bracket 8, fixing the mounting bracket 8 to the end cap 5 and preventing it from rotating with the inner cylinder 3 and the outer cylinder 4, thus achieving the switching of the working states of the mounting bracket 8.

[0033] The mounting bracket 8 has a mandrel that passes through the end cover 5 at its center. The end of the mandrel extends out of the end cover 5 and is equipped with a handle 26, which allows the operator to adjust the angle of the mounting bracket 8 from outside the furnace body 2 by turning the handle 26 so that the locking hole on the mounting bracket 8 corresponds to the through hole on the outer cylinder 4 or the end cover 5, making it easy to perform the locking operation.

[0034] Working Principle: When the mounting frame 8 is rotating, the locking element is inserted into the corresponding through hole of the outer cylinder 4, locking the mounting frame 8 to the inner wall of the outer cylinder 4. At this time, the mounting frame 8 and the outer cylinder 4 form a whole, rotating synchronously with the rotation of the inner cylinder 3 and the outer cylinder 4. Since the spiral plates 11 on the inner support 9 and the outer support 10 abut against the inner walls of the inner cylinder 3 and the outer cylinder 4, the spiral plates 11 also rotate during the rotation of the mounting frame 8. The spiral shape of the spiral plates 11 causes the material to be continuously lifted and then fallen in the furnace, changing the position of the material in the furnace and allowing it to fully contact the hot air, thereby obtaining a more uniform heating effect.

[0035] When the mounting bracket 8 is stationary, first release the locking mechanism between the mounting bracket 8 and the outer cylinder 4, then insert the locking element into the corresponding through hole of the end cover 5 and the mounting bracket 8, locking the mounting bracket 8 to the end cover 5. At this time, the mounting bracket 8 no longer rotates with the inner cylinder 3 and the outer cylinder 4, while the inner cylinder 3 and the outer cylinder 4 can rotate normally. Because the spiral plate 11 abuts against the inner wall of the inner cylinder 3 and the outer cylinder 4, relative rotation occurs between the spiral plate 11 and the inner wall. The spiral plate 11 can scrape off the clumps formed on the inner wall of the inner cylinder 3 and the outer cylinder 4 due to long-term adhesion of wet material, ensuring the cleanliness of the inside of the furnace body 2 and reducing the impact of clumps on the calcination effect of the material.

[0036] In some examples, such as Figure 2 , Figure 3 As shown, the mounting box 12 is mounted on the frame 1, and the feed hopper 13 is installed inside the mounting box 12. The lower port of the feed hopper 13 is connected to the small-diameter end of the inner cylinder 3 to ensure that the material can smoothly enter the inner cylinder 3. The bottom of the mounting box 12 is provided with a discharge port 14 that is connected to the discharge port 7 on the end cover 5. The side wall of the mounting box 12 is provided with a heating port 15, which is used to connect to the burner to provide heat to the furnace body 2.

[0037] Working principle: The feed hopper 13, discharge port 14, and heating port 15 are integrated into the mounting box 12, realizing the integration of the equipment structure, simplifying the overall layout of the equipment, and making maintenance and repair more convenient. The feed hopper 13 is responsible for introducing materials into the furnace body 2. Through the connection with the small diameter end of the inner cylinder 3, the materials enter the furnace body 2. The discharge port 14 is responsible for discharging the calcined products. The heating port 15 is connected to the burner to provide continuous heat to the furnace body 2 to meet the high-temperature conditions required for calcination of the materials.

[0038] The material enters the inner cylinder 3 from the feed hopper 13 at the small diameter end, and then enters the inner cylinder 3 to begin calcination. After calcination, the material is discharged from the discharge port 7 on the end cap 5 located on the large diameter end of the outer cylinder 4, and is transported to subsequent processing equipment through the discharge port 14. At the same time, the high-temperature hot gas flow generated by the burner enters the furnace body 2 through the heating port 15 to provide the heat required for the calcination of the material.

[0039] In some examples, such as Figures 2-5 As shown, a conical heat collection hood 16 is installed inside the mounting box 12 to collect the waste heat airflow rising after the material is discharged from the outlet 7 on the end cover 5. A heat transfer tube 17 is installed inside the feed hopper 13, penetrating the bottom wall of the feed hopper 13 and abutting against the top of the heat collection hood 16, communicating with the heat collection hood 16. Multiple heat dissipation holes 18 are evenly distributed on the tube wall of the heat transfer tube 17 to transfer heat to the material in the feed hopper 13. In addition, the heat transfer tube 17 can be pulled out directly upwards for cleaning when cleaning is required.

[0040] A fixed plate 19 is provided on the outer wall of the heat transfer tube 17. The fixed plate 19 is conical, and multiple first material leakage holes 20 are evenly arranged circumferentially on the fixed plate 19. A rotating frame 21 is rotatably arranged inside the feed hopper 13. A rotating plate 22 is mounted on the rotating frame 21 and is attached to the bottom surface of the fixed plate 19. The rotating plate 22 is also conical, and multiple second material leakage holes 23 are arranged circumferentially on the rotating plate 22. When the rotating plate 22 rotates, the second material leakage holes 23 and the first material leakage holes 20 will intermittently connect or block, thereby realizing intermittent material discharge. A gear ring 24 is provided on the rotating frame 21 and is rotatably mounted on the top of the feed hopper 13. A gear 25 that meshes with the gear ring 24 is rotatably arranged on the outer wall of the feed hopper 13. The gear 25 is driven by a motor installed on the outer wall of the feed hopper 13. The fixed plate 19 and the heat transfer tube 17, as well as the rotating plate 22 and the rotating frame 21, are detachable, making it easy to remove the fixed plate 19 and the rotating plate 22 for cleaning.

[0041] Working principle: After calcination, the material is discharged from the outlet 7 on the end cap 5 and falls to the discharge port 14, while the generated waste heat flow rises. The conical heat collector hood 16 concentrates and guides the rising waste heat flow into the heat transfer tube 17. The waste heat flow in the heat transfer tube 17 escapes into the feed hopper 13 through the heat dissipation holes 18, where it exchanges heat with the material in the feed hopper 13, achieving pre-drying of the material and thus fully utilizing the heat of the waste heat flow.

[0042] The rotating disk 22 on the rotating frame 21 rotates under the drive of a motor. Since the second discharge hole 23 on the rotating disk 22 corresponds to the first discharge hole 20 on the fixed disk 19 and its position can change with the rotation of the rotating disk 22, the second discharge hole 23 and the first discharge hole 20 will periodically align and stagger when the rotating disk 22 rotates. When aligned, the material falls through the discharge hole; when staggered, the discharge hole is blocked, and the material stops falling, thus achieving intermittent material discharge. This allows the material to have more time to contact the waste heat flow in the feed hopper 13, enhancing the preheating effect and ensuring that the waste heat flow is fully utilized. The fixed disk 19 and the rotating disk 22 are conical, causing the material to naturally move away from the heat transfer tube 17 under gravity, preventing the material from accumulating around the heat transfer tube 17 and blocking the heat dissipation holes 18, ensuring that the waste heat flow can dissipate smoothly and fully contact the material.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A calcining furnace for producing soda ash from waste sodium sulfate, characterized in that, The furnace includes a frame (1) and a furnace body (2). The furnace body (2) includes an inner cylinder (3), an outer cylinder (4) and an end cap (5). The inner cylinder (3) and the outer cylinder (4) are connected and coaxially nested and rotatably mounted on the frame (1). The inner cylinder (3) and the outer cylinder (4) are both conical and have opposite orientations at their large diameter ends. There are two end caps (5) mounted on the frame (1). The two end caps (5) are used to seal both ends of the outer cylinder (4). The end caps (5) are rotatably fitted with the ends of the outer cylinder (4). The small-diameter end of the inner cylinder (3) passes through the end cap of the large-diameter end of the outer cylinder (4) for material entry and guiding the material to the small-diameter end of the outer cylinder (4). The outer cylinder (4) can receive the material in the inner cylinder (3) and guide the material to move to the large-diameter end. The end cap (5) of the large-diameter end of the outer cylinder (4) has a discharge port (7).

2. The calcining furnace for producing soda ash from waste sodium sulfate according to claim 1, characterized in that, The furnace body (2) is rotatably provided with an installation frame (8). The installation frame (8) is provided with an inner support (9) extending into the inner cylinder (3) and an outer support (10) extending between the inner cylinder (3) and the outer cylinder (4). Both the inner support (9) and the outer support (10) are provided with multiple spiral plates (11). The spiral plates (11) on the inner support (9) are in contact with the inner wall of the inner cylinder (3), and the spiral plates (11) on the outer support (10) are in contact with the inner wall of the outer cylinder (4). The furnace body (2) is provided with locking members on the outside for locking the installation frame (8) and the outer cylinder (4), or locking the installation frame (8) and the end cover (5).

3. The calcining furnace for producing soda ash from waste sodium sulfate according to claim 2, characterized in that, The mounting bracket (8) has a rotating state and a stationary state; When the mounting frame (8) is in a rotating state, the locking member is used to lock the mounting frame (8) and the outer cylinder (4). The mounting frame (8) can rotate synchronously with the outer cylinder (4) to intermittently lift the material with the help of the spiral plate (11). When the mounting bracket (8) is stationary, the locking element is used to lock the mounting bracket (8) and the end cap (5). The mounting bracket (8) can scrape off the material on the inner wall of the outer cylinder (4) and the inner cylinder (3) by means of the spiral plate (11) when the outer cylinder (4) rotates.

4. The calcining furnace for producing soda ash from waste sodium sulfate according to claim 1, characterized in that, The frame (1) is provided with an installation box (12) located at the large diameter end of the outer cylinder (4). The installation box (12) has a heating port (15) for connecting the burner on one side. The installation box (12) is provided with a feed hopper (13) that penetrates the top wall of the installation box (12). The bottom of the feed hopper (13) is connected to the small diameter end of the inner cylinder (3). The bottom of the installation box (12) has a discharge port (14) that is connected to the discharge port (7).

5. A calcining furnace for producing soda ash from waste sodium sulfate according to claim 4, characterized in that, The installation box (12) has a conical heat collection cover (16) inside. The heat collection cover (16) is located below the feed hopper (13) and is set below the heating port (15) to collect the waste heat gas flow discharged from the discharge port (7). The feed hopper (13) is provided with a heat transfer tube (17). The heat transfer tube (17) has multiple heat dissipation holes (18) on its peripheral wall. The heat transfer tube (17) penetrates the bottom wall of the feed hopper (13) and communicates with the area below the heat collection cover (16). The heat transfer tube (17) can dissipate the waste heat gas collected by the heat collection cover (16) through the heat dissipation hole (18) into the feed hopper (13) to pre-dry the material in the feed hopper (13).

6. A calcining furnace for producing soda ash from waste sodium sulfate according to claim 5, characterized in that, The heat transfer tube (17) is fitted with a fixed plate (19) on its outer periphery. The fixed plate (19) is provided with a plurality of first material leakage holes (20). A rotating frame (21) is rotatably installed inside the feed hopper (13). A rotating plate (22) is rotatably fitted on the outer periphery of the heat transfer tube (17) and located below the fixed plate (19). The rotating plate (22) is provided with a plurality of second material leakage holes (23). After the rotating disk (22) rotates, it can intermittently connect the second discharge hole (23) and the first discharge hole (20) to allow intermittent material discharge.

7. A calcining furnace for producing soda ash from waste sodium sulfate according to claim 6, characterized in that, Both the fixed disk (19) and the rotating disk (22) are cones with downward openings. The fixed disk (19) enables the material to flow away from the heat transfer tube (17).

8. A calcining furnace for producing soda ash from waste sodium sulfate according to claim 6, characterized in that, The rotating frame (21) is provided with a gear ring (24), which is located on the outer periphery of the feed hopper (13). A gear (25) is rotatably provided on the outer side of the feed hopper (13) to mesh with the gear ring (24) and drive the gear ring (24) to rotate.

9. A calcining furnace for producing soda ash from waste sodium sulfate according to claim 8, characterized in that, The fixed disk (19) and the heat transfer tube (17) can be detachably connected, as can the rotating disk (22) and the rotating frame (21).

10. A calcining furnace for producing soda ash from waste sodium sulfate according to claim 3, characterized in that, The mounting bracket (8) has a spindle that passes through the end cap (5) at its center, and the end of the spindle has a handle (26).

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