Hot air circulating device of smelting furnace

Abstract

The utility model discloses a hot air circulating device of a smelting furnace, which relates to the technical field of hot air circulating devices of smelting furnaces and comprises a furnace body, an emission reduction unit for filtering nitrogen oxides, an air blowing unit for improving the filtering effect and a circulating unit, a reaction box is installed on one side of the furnace body, a temperature control assembly is arranged at the lower end of the reaction box, a stirring unit used for evenly mixing hot air is arranged at the upper end in the furnace body, and a circulation unit is installed on the furnace body. The emission reduction unit comprises a box inlet air pipe mounted at the upper end in the reaction box, the air outlet end of the box inlet air pipe is connected with a transverse pipe, and air outlet holes are formed in the upper end of the transverse pipe at equal intervals; according to the utility model, by utilizing the Karman vortex street effect, flue gas is ejected upwards in a swinging manner, so that the contact area with ammonia, a catalyst and the like can be increased, and the comprehensiveness of catalytic reduction of nitrogen oxides is improved; ammonia is discharged from the ammonia outlet hole, and can enter the elliptic cylinder again from the ammonia collecting hole to circulate by utilizing the Bernoulli principle, so that the utilization rate of the ammonia is improved, and more cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of hot air circulation devices for smelting furnaces, in particular to a hot air circulation device for smelting furnaces. Background Art

[0002] A melting furnace is a device used to heat metal or other materials to a high temperature for melting, casting, mixing and processing. Hot air circulation in a melting furnace can improve melting efficiency, evenly distribute heat in the furnace, thereby accelerating the melting process, increasing the temperature in the furnace, promoting the melting and alloying of metals, and making the metal melt more uniform; it can save energy, recycle waste gas, recycle heat, and reduce energy consumption and waste gas emissions; it can reduce environmental pollution, recycle hot air, reduce waste gas emissions, and reduce the impact on the environment; it can improve the working environment, alleviate the temperature difference in the furnace area, and reduce the intensity of operators working in a high temperature environment and the harm to the workplace. Nitrogen oxides produced by melting furnaces are one of the air pollutants, and corresponding measures need to be taken to reduce emissions; most of them use selective catalytic reduction (SCR): by injecting ammonia (NH3) into the flue gas, catalytically reducing nitrogen oxides (NOx) into nitrogen (N2) and water (H2O) in the high temperature area, so as to achieve the purpose of reducing nitrogen oxide emissions. SCR technology is widely used in thermal power plants, steel, cement, glass and other industrial fields. It is one of the most widely used and effective nitrogen oxide control technologies.

[0003] In the prior art, a heat recycling device for a hot blast furnace disclosed in the patent with announcement number CN218820987U mainly filters the exhaust gas through a filter plate when circulating the hot air, and has a poor effect of filtering and cleaning the hot gas exhausted from the furnace.

[0004] It is known from the technology in the related field that for the hot air circulation device of the smelting furnace, the nitrogen oxides and the like generated during the smelting process are mostly filtered through filters when the hot air is circulated. The filtration of the nitrogen oxides contained in the hot air is not comprehensive enough, and the effect of filtering the nitrogen oxides with excessive content in the hot air is poor. Utility Model Content

[0005] The purpose of the utility model is to provide a hot air circulation device for a smelting furnace in order to solve the above problems.

[0006] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0007] A hot air circulation device for a smelting furnace, comprising a furnace body, an emission reduction unit for filtering nitrogen oxides, an air blowing unit for improving the filtering effect, and a circulation unit;

[0008] Furnace body: A reaction box is installed on one side, a temperature control component is provided at the lower end of the reaction box, a stirring unit for mixing hot gas is provided at the upper end of the interior of the furnace body, and the circulation unit is installed on the furnace body; the interior of the reaction box and the furnace body can be heat-conducted, and the heat inside the furnace body can be transferred to the reaction box to raise the internal temperature, thereby catalytically reducing nitrogen oxides in the high-temperature area.

[0009] Emission reduction unit: comprising an air inlet pipe installed at the upper end of the reaction box, the outlet end of the air inlet pipe is connected to a transverse pipe, the upper end of the transverse pipe is provided with air outlet holes at equal intervals, and the transverse pipe is provided with a baffle located on the upper side of the air outlet holes. When the high-temperature flue gas in the furnace body enters the air inlet pipe at a certain flow rate, it can be discharged from the air outlet holes on the upper side of the transverse pipe. When being discharged, due to the obstruction of the baffle, the flue gas after passing through the baffle can be sprayed upward in a swinging shape by utilizing the Karman vortex street effect. An ammonia adding pipe is provided at the rear end of the box, and the gas outlet end of the ammonia adding pipe is connected to an ellipsoidal cylinder. Ammonia outlet holes are equidistantly provided on the front half of the inner circumference of the ellipsoidal cylinder, and ammonia receiving holes are equidistantly provided on the rear half of the inner circumference of the ellipsoidal cylinder. A clean gas outlet pipe is provided at the lower side of the reaction box. External ammonia flows into the ellipsoidal cylinder through the ammonia adding pipe. Since the aperture of the ammonia outlet hole is larger than that of the ammonia receiving hole, ammonia can be discharged from the ammonia outlet hole by utilizing the Bernoulli principle. After fully contacting and reacting with the swinging flue gas, it can re-enter the ellipsoidal cylinder from the ammonia receiving hole for circulation.

[0010] Blowing unit: It includes a positive pressure air pipe installed at the front end of the reaction box. The outlet end of the positive pressure air pipe is connected to a blowing ring. The lower circumference of the blowing ring is equidistantly provided with spiral long holes. The blowing ring is located above the ammonia outlet area on the elliptical cylinder. When catalytic reduction of nitrogen oxides is performed, external gas can be blown out through the spiral long holes on the blowing ring. At the same time, the spiral long holes have a certain taper, which can make the gas rotate and blow inward.

[0011] Furthermore, the stirring unit comprises a fixed bar installed at the upper end of the furnace body, the middle part of the fixed bar is rotatably connected to a plate shaft, a threaded plate is installed on the plate shaft, and stirring rods are equidistantly arranged on the circumference of the lower end of the plate shaft. When the flue gas circulates, the flue gas flows out from the upper end of the furnace body, and the flue gas exerts force on the threaded plate when flowing, and the stirring rods on the plate shaft can be rotated through the threaded plate.

[0012] Furthermore, the circulation unit comprises an outlet pipe with one end connected to the middle of the upper end of the furnace body, and the other end of the outlet pipe is connected to the air inlet end of the inlet air pipe, and the outlet pipe is provided with an exhaust mechanism and a dust filter mechanism. The exhaust mechanism can extract the flue gas in the furnace body, and after extraction, the large particles in the flue gas can be filtered by the dust filter mechanism, and then the nitrogen oxides are catalytically reduced, and the hot gas rises to the upper side of the reaction box and can flow back into the furnace body.

[0013] Furthermore, the circulation unit further comprises a furnace inlet pipe having one end connected to the upper side of the front end of the reaction box, and the other end of the furnace inlet pipe is connected to the furnace body. The pure hot gas on the upper side of the reaction box can flow back into the furnace body through the furnace inlet pipe.

[0014] Furthermore, another set of the exhaust mechanism is provided on the furnace inlet pipe. When the exhaust mechanism on the furnace inlet pipe works, the pure hot air on the upper side of the reaction box can be drawn into the furnace body, so that the hot air is blown tangentially into the furnace body, thereby increasing the kinetic energy of the pure hot air.

[0015] Furthermore, the temperature control assembly includes a lifting mechanism, the lower end of the reaction box is slidably connected to a heat insulation blocking plate, and the lower end of the heat insulation blocking plate is connected to the lifting end of the lifting mechanism. The heat insulation blocking plate can be raised and lowered by operating the lifting mechanism, thereby changing the area of ​​heat conduction between the reaction box and the furnace body, and realizing the control of the temperature in the reaction box.

[0016] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0017] 1. In the utility model, the high temperature in the furnace body is discharged from the air outlet and blocked by the baffle. By utilizing the Karman vortex street effect, the flue gas after passing through the baffle is ejected upward in a swinging state, which can increase the contact area with ammonia, catalyst, etc., and improve the comprehensiveness of catalytic reduction of nitrogen oxides; ammonia is discharged from the ammonia outlet, and after fully contacting and reacting with the swinging flue gas, it can re-enter the elliptical cylinder from the ammonia receiving hole for circulation by utilizing the Bernoulli principle, thereby improving the utilization rate of ammonia, saving more energy and saving costs.

[0018] 2. In the utility model, when catalytically reducing nitrogen oxides, external gas is blown out through the spiral long holes on the blowing ring, which can further stir the ammonia and flue gas and enhance the comprehensiveness of the catalytic reduction of nitrogen oxides. At the same time, part of the gas can flow back into the furnace body with the hot gas to ensure the stability of the pressure in the furnace body, achieve better emission reduction effects, and be more stable in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 It is a schematic diagram of the overall structure of a hot air circulation device for a smelting furnace described in the utility model;

[0021] Figure 2 It is a front side cross-sectional structural schematic diagram of a hot air circulation device for a smelting furnace described in the utility model;

[0022] Figure 3 It is a schematic diagram of the explosion structure of a hot air circulation device for a smelting furnace described in the utility model;

[0023] Figure 4 It is a schematic structural diagram of the coordination of the box air inlet pipe, the elliptical cylinder and the air blowing ring of a hot air circulation device for a smelting furnace described in the utility model;

[0024] Figure 5 It is a schematic diagram of a side cross-sectional structure of the cooperation of the box inlet air pipe, the elliptical cylinder and the blowing ring part of a hot air circulation device for a smelting furnace described in the utility model;

[0025] Figure 6 It is a front side cross-sectional structural diagram of the cooperation between the box inlet air pipe and the elliptical cylinder part of a hot air circulation device for a smelting furnace described in the utility model;

[0026] Figure 7 It is a structural schematic diagram of the upper side of the inner part of the elliptical cylinder of a hot air circulation device for a smelting furnace described in the utility model;

[0027] Figure 8 It is a structural schematic diagram of the blowing ring part of a hot air circulation device for a smelting furnace described in the utility model;

[0028] Fig. 9 It is a structural schematic diagram of a transverse pipe portion of a hot air circulation device for a smelting furnace described in the utility model.

[0029] The following are the descriptions of the reference numerals:

[0030] 1. Furnace body; 2. Reaction box; 3. Inlet air pipe; 4. Horizontal pipe; 5. Air outlet; 6. Baffle rod; 7. Ammonia adding pipe; 8. Elliptical cylinder; 9. Ammonia outlet hole; 10. Positive pressure air pipe; 11. Blowing ring; 12. Spiral long hole; 13. Ammonia collecting hole; 14. Furnace outlet pipe; 15. Air extraction mechanism; 16. Dust filtering mechanism; 17. Fixed bar; 18. Threaded plate; 19. Stirring rod; 20. Furnace inlet pipe; 21. Clean air outlet pipe; 22. Heat insulation blocking plate. DETAILED DESCRIPTION

[0031] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0033] The utility model is further described below in conjunction with the accompanying drawings:

[0034] Example

[0035] like Figure 1-Figure 9 As shown, a hot air circulation device for a smelting furnace comprises a furnace body 1, an emission reduction unit for filtering nitrogen oxides, an air blowing unit for improving the filtering effect, and a circulation unit;

[0036] Furnace body 1: A reaction box 2 is installed on one side, a temperature control component is provided at the lower end of the reaction box 2, a stirring unit for mixing hot air is provided at the upper end of the interior of the furnace body 1, and a circulation unit is installed on the furnace body 1; Figure 1 , Figure 2 and Figure 3 As shown, the interior of the reaction box 2 and the furnace body 1 can be heat-conducted, and the heat inside the furnace body 1 can be transferred to the reaction box 2 to increase the internal temperature, catalytically reducing nitrogen oxides in the high-temperature area, providing an environmental basis for emission reduction.

[0037] The emission reduction unit comprises an inlet air pipe 3 installed at the upper end of the reaction box 2, the outlet end of the inlet air pipe 3 is connected to a transverse pipe 4, the upper end of the transverse pipe 4 is provided with air outlet holes 5 at equal intervals, and the transverse pipe 4 is provided with a blocking rod 6 located on the upper side of the air outlet holes 5, such as Figure 2, Figure 4 , Figure 5 , Figure 6 and Fig. 9 As shown, when the high-temperature flue gas in the furnace body 1 enters the box air inlet pipe 3 at a certain flow rate, it can be discharged from the air outlet 5 on the upper side of the horizontal pipe 4. When discharged, due to the obstruction of the baffle rod 6, the flue gas after passing through the baffle rod 6 can be swung upward by utilizing the Karman vortex street effect, thereby increasing the contact area with ammonia, catalyst, etc., improving the comprehensiveness of catalytic reduction of nitrogen oxides, and having a better effect on filtering nitrogen oxides with excessive content when circulating hot air. An ammonia adding pipe 7 is provided at the rear end of the reaction box 2, and an elliptical cylinder 8 is connected to the air outlet end of the ammonia adding pipe 7. Ammonia outlet holes 9 are equidistantly provided on the front half of the inner circumference of the elliptical cylinder 8, and ammonia receiving holes 13 are equidistantly provided on the rear half of the inner circumference of the elliptical cylinder 8. A clean air outlet pipe 21 is provided at the lower side of the reaction box 2; as shown Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Fig. 9 As shown, external ammonia flows into the elliptical cylinder 8 through the ammonia adding pipe 7. Since the aperture of the ammonia outlet hole 9 is larger than the ammonia receiving hole 13, the ammonia can be discharged from the ammonia outlet hole 9 by using the Bernoulli principle. After fully contacting and reacting with the swinging flue gas, it can re-enter the elliptical cylinder 8 from the ammonia receiving hole 13 for circulation, which can improve the utilization rate of ammonia and save more energy and cost during the catalytic reduction of nitrogen oxides.

[0038] The blowing unit comprises a positive pressure air pipe 10 installed at the front end of the reaction box 2. The outlet end of the positive pressure air pipe 10 is connected to a blowing ring 11. The lower circumference of the blowing ring 11 is provided with spiral long holes 12 at equal intervals. Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, the blowing ring 11 is located above the ammonia outlet 9 area on the elliptical cylinder 8. When catalytic reduction of nitrogen oxides is carried out, the external gas can be blown out through the spiral long hole 12 on the blowing ring 11. At the same time, the spiral long hole 12 has a certain taper, which can make the gas rotate and blow inward, further stir the ammonia and the flue gas, further enhance the comprehensiveness of the catalytic reduction of nitrogen oxides, and achieve a better emission reduction effect.

[0039] The stirring unit comprises a fixed bar 17 installed at the upper end of the furnace body 1, the middle of the fixed bar 17 is rotatably connected to a plate shaft, a threaded plate 18 is installed on the plate shaft, and stirring rods 19 are equidistantly arranged at the lower end of the plate shaft. Figure 1 , Figure 2 and Figure 3As shown, when the flue gas circulation is carried out, the flue gas flows out from the upper end of the furnace body 1. The flue gas exerts force on the threaded plate 18 when flowing, and the threaded plate 18 can rotate with the stirring rod 19 on the plate shaft to achieve stirring of the hot air inside the furnace body 1, thereby ensuring the uniformity of the hot air inside the furnace body 1 and further stabilizing the smelting effect.

[0040] The circulation unit comprises an outlet pipe 14 connected at one end to the middle of the upper end of the furnace body 1, and the other end of the outlet pipe 14 is connected to the air inlet end of the inlet air pipe 3. The outlet pipe 14 is provided with an exhaust mechanism 15 and a dust filter mechanism 16. Figure 1 , Figure 2 and Figure 3 As shown, the exhaust mechanism 15 can extract the flue gas in the furnace body 1. After being extracted, the large particles in the flue gas can be filtered through the dust filtering mechanism 16. Then, after catalytic reduction of the nitrogen oxides, the hot gas rises to the upper side of the reaction box 2 and can flow back into the furnace body 1 to realize the circulation of hot air.

[0041] The circulation unit further comprises a furnace inlet pipe 20 having one end connected to the upper side of the front end of the reaction box 2, and the other end of the furnace inlet pipe 20 is connected to the furnace body 1. Figure 1 , Figure 2 and Figure 3 As shown, the pure hot air on the upper side of the reaction box 2 can flow back into the furnace body 1 through the furnace inlet pipe 20.

[0042] Another set of exhaust mechanism 15 is provided on the furnace inlet pipe 20. Figure 1 , Figure 2 and Figure 3 As shown, the exhaust mechanism 15 on the furnace inlet pipe 20 works to draw the pure hot air on the upper side of the reaction box 2 into the furnace body 1, so that the hot air is blown tangentially into the furnace body 1, thereby increasing the kinetic energy of the pure hot air and further stabilizing the uniformity of the hot air in the furnace body 1.

[0043] The temperature control assembly includes a lifting mechanism, and the lower end of the reaction box 2 is slidably connected to a heat insulation blocking plate 22, and the lower end of the heat insulation blocking plate 22 is connected to the lifting end of the lifting mechanism. Figure 1 , Figure 2 and Figure 3 As shown, the heat insulation blocking plate 22 can be raised or lowered by operating the lifting mechanism, thereby changing the heat conduction area between the reaction box 2 and the furnace body 1, achieving control of the temperature in the reaction box 2, and ensuring the stability of the catalytic reduction of nitrogen oxides.

[0044] Working principle: When in use, Figure 1-Figure 9As shown, the exhaust mechanism 15 works to extract the flue gas in the furnace body 1, and after being extracted, the large particles in the flue gas are filtered by the dust filter mechanism 16. Then, the flue gas enters the reaction box 2 to catalytically reduce the nitrogen oxides, and the pure hot air rises to the upper side of the reaction box 2. The exhaust mechanism 15 on the furnace inlet pipe 20 works to extract the pure hot air on the upper side of the reaction box 2 into the furnace body 1, so that the hot air is blown tangentially into the furnace body 1, thereby increasing the kinetic energy of the pure hot air, facilitating mixing with the hot air in the furnace body 1, and completing the circulation of the hot air;

[0045] like Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Fig. 9 As shown, when the high-temperature flue gas in the furnace body 1 enters the box air inlet pipe 3 at a certain flow rate, it can be discharged from the air outlet 5 on the upper side of the horizontal pipe 4. When discharged, due to the obstruction of the baffle 6, the flue gas after passing through the baffle 6 can be sprayed upward in a swinging state by utilizing the Karman vortex street effect, which can increase the contact area with ammonia, catalyst, etc., improve the comprehensiveness of catalytic reduction of nitrogen oxides, and have a better effect on filtering nitrogen oxides with excessive content when circulating hot gas. External ammonia flows into the elliptical cylinder 8 through the ammonia adding pipe 7. Since the aperture of the ammonia outlet hole 9 is larger than the ammonia receiving hole 13, ammonia can be discharged from the ammonia outlet hole 9 by utilizing the Bernoulli principle. After fully contacting and reacting with the swinging flue gas, it can enter the elliptical cylinder 8 again from the ammonia receiving hole 13 for circulation, which can improve the utilization rate of ammonia, and save energy and cost when catalytically reducing nitrogen oxides.

[0046] like Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, the blowing ring 11 is located above the ammonia outlet 9 area on the elliptical cylinder 8. When catalytic reduction of nitrogen oxides is performed, external gas can be blown out through the spiral long hole 12 on the blowing ring 11. At the same time, the spiral long hole 12 has a certain taper, which can make the gas rotate and blow inward, further stir the ammonia and the flue gas, and further enhance the comprehensiveness of the catalytic reduction of nitrogen oxides. At the same time, part of the gas can flow back into the furnace body 1 with the hot gas, ensuring the stability of the pressure in the furnace body 1, and the emission reduction effect is better and the use is more stable;

[0047] like Figure 1 , Figure 2 and Figure 3 As shown, when the flue gas circulation is carried out, the flue gas flows out from the upper end of the furnace body 1. The flue gas exerts force on the threaded plate 18 when flowing, and the threaded plate 18 can rotate with the stirring rod 19 on the plate shaft to achieve stirring of the hot air inside the furnace body 1, thereby ensuring the uniformity of the hot air inside the furnace body 1 and further stabilizing the smelting effect.

[0048] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, and these changes and improvements fall within the scope of the utility model to be protected.

Claims

1. A hot air circulation device for a smelting furnace, characterized in that: include: A furnace body (1), an emission reduction unit for filtering nitrogen oxides, an air blowing unit for improving the filtering effect, and a circulation unit; A furnace body (1): a reaction box (2) is installed on one side, a temperature control component is provided at the lower end of the reaction box (2), a stirring unit for mixing hot air is provided at the upper end of the furnace body (1), and the circulation unit is installed on the furnace body (1); The emission reduction unit comprises an air inlet pipe (3) installed at the upper end of the reaction box (2), the air outlet end of the air inlet pipe (3) is connected to a transverse pipe (4), the upper end of the transverse pipe (4) is provided with air outlet holes (5) at equal intervals, the transverse pipe (4) is provided with a blocking rod (6) located on the upper side of the air outlet holes (5), the rear end of the reaction box (2) is provided with an ammonia adding pipe (7), the air outlet end of the ammonia adding pipe (7) is connected to an elliptical cylinder (8), the front half of the inner circumference of the elliptical cylinder (8) is provided with ammonia outlet holes (9) at equal intervals, the rear half of the inner circumference of the elliptical cylinder (8) is provided with ammonia receiving holes (13) at equal intervals, and a clean air outlet pipe (21) is provided at the lower side of one side of the reaction box (2); The blowing unit comprises a positive pressure air pipe (10) installed at the front end of the reaction box (2), the outlet end of the positive pressure air pipe (10) is connected to a blowing ring (11), and spiral long holes (12) are equidistantly provided on the lower circumference of the blowing ring (11).

2. A hot air circulation device for a smelting furnace according to claim 1, characterized in that: The stirring unit comprises a fixed bar (17) installed at the upper end of the furnace body (1), the middle part of the fixed bar (17) is rotatably connected to a plate shaft, a threaded plate (18) is installed on the plate shaft, and stirring rods (19) are equidistantly arranged on the circumference of the lower end of the plate shaft.

3. The hot air circulation device for a smelting furnace according to claim 1, characterized in that: The circulation unit comprises an outlet pipe (14) having one end connected to the middle of the upper end of the furnace body (1), the other end of the outlet pipe (14) being connected to the air inlet end of the box air inlet pipe (3), and an air extraction mechanism (15) and a dust filtering mechanism (16) being provided on the outlet pipe (14).

4. A hot air circulation device for a smelting furnace according to claim 3, characterized in that: The circulation unit further comprises a furnace inlet pipe (20) with one end connected to the upper front end of the reaction box (2), and the other end of the furnace inlet pipe (20) is connected to the furnace body (1).

5. A hot air circulation device for a smelting furnace according to claim 4, characterized in that: Another set of the air extraction mechanisms (15) is provided on the furnace inlet pipe (20).

6. A hot air circulation device for a smelting furnace according to claim 1, characterized in that: The temperature control component comprises a lifting mechanism, the lower end of the reaction box (2) is slidably connected to a heat insulation blocking plate (22), and the lower end of the heat insulation blocking plate (22) is connected to the lifting end of the lifting mechanism.

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