Cross air supply flue gas circulation system suitable for magnetite belt type roasting machine

Abstract

The invention provides a cross air supply flue gas circulation system suitable for a magnetite belt type roasting machine. The cross air supply flue gas circulation system comprises a belt type roasting machine body, and the belt type roasting machine body comprises a forced air drying section, a preheating section, a first cooling section and a second cooling section which are arranged in the material flow advancing direction; the air blowing drying section is communicated with the first cooling section through the first flue gas circulation hot air return pipeline and used for guiding hot air into the first cooling section, and the preheating section is communicated with the second cooling section through the second flue gas circulation hot air return pipeline and used for guiding hot air into the second cooling section. The forced air drying section is communicated with the first cooling section through the first flue gas circulation hot air return pipeline, the preheating section is communicated with the second cooling section through the second flue gas circulation hot air return pipeline, recycling of hot waste gas of the forced air drying section and the preheating section is achieved, and heat waste caused by direct exhaust of flue gas is reduced. By arranging the first cross air supply pipeline and the second cross air supply pipeline, the air supply form is adjusted, and heat distribution is optimized.

Description

Technical Field

[0001] The present application belongs to the technical field of pellet production in the iron and steel metallurgical industry, and specifically relates to a cross-air supply flue gas circulation system suitable for a magnetite belt roaster. Background Art

[0002] In the pellet production process, the belt roaster is one of the main production equipment for iron ore pellets. Along the direction of material flow, the belt roaster is divided into a blast drying section, an exhaust drying section, a preheating section, a roasting section, a soaking section, and a cooling section.

[0003] In the existing belt roasting machine, the flue gas from the blast drying section, exhaust drying section and preheating section all needs to be discharged to the outside. The heat in the flue gas has recycling value, resulting in energy waste.

[0004] In existing belt roasters, there is no partition between the cooling section and the soaking section. The hot air displaced from the front end of the cooling section is the hottest and flows directly into the soaking section. The hot air from the middle cooling section outlet flows into the roasting section, resulting in unreasonable heat distribution. Summary of the Invention

[0005] Therefore, the purpose of the present application is to solve at least one of the above-mentioned technical problems and to provide a cross-air supply flue gas circulation system suitable for a magnetite belt roaster, comprising a belt roaster body, wherein the belt roaster body comprises a blast drying section, a preheating section, a first cooling section and a second cooling section arranged along the forward direction of the material flow; the cross-air supply flue gas circulation system suitable for a magnetite belt roaster also comprises a first flue gas circulation return hot air duct and a second flue gas circulation return hot air duct, the blast drying section is connected to the first cooling section through the first flue gas circulation return hot air duct to introduce hot air into the first cooling section, and the preheating section is connected to the second cooling section through the second flue gas circulation return hot air duct to introduce hot air into the second cooling section.

[0006] Optionally, the cross-air supply flue gas circulation system suitable for the magnetite belt roaster includes a roasting section and a soaking section arranged along the forward direction of the material flow, and the roasting section and the soaking section are located between the preheating section and the first cooling section; the cross-air supply flue gas circulation system suitable for the magnetite belt roaster also includes a first cross-air supply duct and a second cross-air supply duct, the first cross-air supply duct is respectively connected to the first cooling section and the roasting section, and the second cross-air supply duct is respectively connected to the second cooling section and the soaking section.

[0007] Optionally, a first hot air exchange valve and a first cold air exchange valve are provided on the first flue gas circulation return hot air duct.

[0008] Optionally, a second hot air valve and a second cold air valve are provided on the second flue gas circulation hot air duct.

[0009] Optionally, the blast drying section includes an upper cover of the blast drying section, the first flue gas circulation return hot air duct is connected to the upper cover of the blast drying section, a furnace hood dust removal system and a flue gas dehydration system are sequentially arranged on the first flue gas circulation return hot air duct along the flow direction, and a first cooling fan is arranged on the first flue gas circulation return hot air duct.

[0010] Optionally, the preheating section includes a preheating section wind box, the second flue gas circulation hot air return duct is connected to the preheating section wind box, and the second flue gas circulation hot air return duct is provided with a flue gas circulation dust removal system and a second cooling fan.

[0011] Optionally, a roasting section upper cover is provided at the end of the roasting section, combustion chambers are provided on both sides of the roasting section upper cover, and the roasting section also includes a roasting section wind box, and the exhaust port of the first cross air supply duct is connected to the combustion chamber so that the exhaust gas enters the roasting section upper cover through the combustion chamber, and passes through the material layer from top to bottom and enters the roasting section wind box.

[0012] Optionally, the heat equalization section includes a heat equalization section upper cover and a heat equalization section wind box, and the exhaust port of the second cross air supply duct is connected to the heat equalization section upper cover so that the exhausted gas passes through the material layer from top to bottom and enters the heat equalization section wind box.

[0013] Optionally, a first partition wall is provided between the heat soaking section and the first cooling section.

[0014] Optionally, a second partition wall is provided between the first cooling section and the second cooling section.

[0015] Beneficial effects: In an embodiment of the present invention, a cross-air supply flue gas circulation system suitable for a magnetite belt roaster is provided. By setting a first flue gas circulation return hot air duct and a second flue gas circulation return hot air duct, and connecting the blast drying section with the first cooling section through the first flue gas circulation return hot air duct, and connecting the preheating section with the second cooling section through the second flue gas circulation return hot air duct, the hot exhaust gas of the blast drying section and the preheating section is recycled and utilized, thereby reducing the heat waste caused by the direct discharge of flue gas and reducing energy consumption. At the same time, by setting a first cross-air supply duct and a second cross-air supply duct, the air supply form of the first cooling section and the second cooling section to the roasting section and the equalizing section is adjusted, the heat distribution is optimized, and the overall thermal efficiency of the system is improved. By circulating the hot exhaust gas of the blast drying section to the first cooling section and the hot exhaust gas of the preheating section to the second cooling section, the impact of the reduction of oxygen content on the entire production process is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a system schematic diagram of a cross-air supply flue gas circulation system applicable to a magnetite belt roaster according to an embodiment of the present application.

[0017] The reference numerals indicate: 1. Blast drying section; 2. Blast drying section upper cover; 3. First flue gas circulation hot air return duct; 4. Furnace hood dust removal system; 5. Flue gas dehydration system; 6. First hot air exchange valve; 7. First cold air exchange valve; 8. Preheating section; 9. Preheating section bellows; 10. Flue gas circulation dust removal system; 11. Second flue gas circulation hot air return duct; 12. Second hot air exchange valve; 13. Second cold air exchange valve; 14. First cooling fan; 15. Second cooling fan; 16. First cross air supply duct; 17. Second cross air supply duct; 18. First partition wall; 19. Second partition wall; 20. Combustion chamber; 21. Drying section; 22. Roasting section; 23. Soaking section; 24. First cooling section; 25. Second cooling section; 26. Third cooling section. DETAILED DESCRIPTION

[0018] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0020] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0021] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0022] like Figure 1 As shown, according to an embodiment of the present application, a cross-air supply flue gas circulation system suitable for a magnetite belt roaster is provided, including a belt roaster body, the belt roaster body including a blast drying section 1, a preheating section 8, a first cooling section 24 and a second cooling section 25 arranged along the forward direction of the material flow.

[0023] The cross-air supply flue gas circulation system suitable for the magnetite belt roaster also includes a first flue gas circulation return hot air duct 3 and a second flue gas circulation return hot air duct 11. The blast drying section 1 is connected to the first cooling section 24 through the first flue gas circulation return hot air duct 3 to introduce hot air into the first cooling section 24, and the preheating section 8 is connected to the second cooling section 25 through the second flue gas circulation return hot air duct 11 to introduce hot air into the second cooling section 25.

[0024] By providing a first flue gas circulation hot air return duct 3 and a second flue gas circulation hot air return duct 11, connecting the blast drying section 1 to the first cooling section 24 via the first flue gas circulation hot air return duct 3, and connecting the preheating section 8 to the second cooling section 25 via the second flue gas circulation hot air return duct 11, the hot exhaust gas from the blast drying section 1 and preheating section 8 is recycled, reducing heat waste caused by direct flue gas discharge and energy consumption. Furthermore, by adjusting the air supply from the first cooling section 24 and the second cooling section 25 to the roasting section and the soaking section, heat distribution is optimized, improving the overall thermal efficiency of the system.

[0025] By circulating the hot exhaust gas from the blast drying section 1 to the first cooling section 24 and the hot exhaust gas from the preheating section 8 to the second cooling section 25, it can better meet the production needs of the cross-air supply flue gas circulation system suitable for the magnetite belt roaster using magnetite as raw material, and avoid the impact of the reduction of oxygen content on the entire production process.

[0026] By providing a first flue gas recirculation hot air duct 3, the hot exhaust gas generated by the blast drying section 1 is directed to the first cooling section 24, enabling better utilization of thermal energy and improving the overall thermal efficiency of the system. The hot exhaust gas from the blast drying section 1 partially replaces the normal-temperature air that would otherwise be blown in by the cooling fan, raising the outlet air temperature of the cooling section and providing more heat for the roasting section 22, thus saving fuel consumption in the roasting section 22. Furthermore, the waste heat from the flue gas is utilized to reduce the amount of flue gas discharged from the system.

[0027] Among them, by setting up a second flue gas circulation hot air duct 11, the hot exhaust gas from the preheating section 8 is introduced into the second cooling section 25, avoiding heat loss caused by direct discharge of flue gas from the preheating section 8 and further improving energy utilization.

[0028] The smoke from the blast drying section 1 is directionally transported to the first cooling section 24, and the smoke from the preheating section 8 is directionally transported to the second cooling section 25, so that the hot air sources in different areas of the cooling section are more reasonable.

[0029] The forward direction of the material flow refers to the direction in which the material moves when the cross-air supply flue gas circulation system of the magnetite belt roaster is working.

[0030] The cross-air supply flue gas circulation system suitable for the magnetite belt roaster includes a roasting section 22 and a soaking section 23 arranged along the forward direction of the material flow. The roasting section 22 and the soaking section 23 are located between the preheating section 8 and the first cooling section 24.

[0031] The cross-air supply flue gas circulation system suitable for the magnetite belt roaster also includes a first cross-air supply duct 16 and a second cross-air supply duct 17. The first cross-air supply duct 16 is connected to the first cooling section 24 and the roasting section 22 respectively, and the second cross-air supply duct 17 is connected to the second cooling section 25 and the equalizing section 23 respectively.

[0032] By providing the first cross air supply duct 16 and the second cross air supply duct 17, the air supply form from the first cooling section and the second cooling section to the roasting section and the soaking section is adjusted, thereby optimizing heat distribution and improving the overall thermal efficiency of the system.

[0033] By providing a first cross air supply duct 16 and a second cross air supply duct 17, the hot air from the first cooling section 24 is introduced into the combustion chamber 20 of the roasting section 22 through the first cross air supply duct 16. This shortens the hot air transmission path, reduces heat loss, provides a high-temperature heat source for the roasting section 22, and reduces fuel consumption. The hot air from the second cooling section 25 is introduced into the soaking section 23 through the second cross air supply duct 17, further optimizing heat distribution.

[0034] By utilizing the hot exhaust gas from the preheating section 8 to partially replace the normal temperature air that originally needed to be blown in by the cooling fan, the outlet air temperature of the cooling section can be increased, providing more heat for the equalizing section 23. By utilizing the waste heat of the flue gas, the amount of flue gas discharged from the system can be reduced.

[0035] Among them, by allowing the hot exhaust gas from the blast drying section 1 and the preheating section 8 to enter the first cooling section 24 and the second cooling section 25, the temperature of the hot air at the outlet of the first cooling section 24 and the second cooling section 25 is increased, providing a higher quality heat source for the subsequent roasting section 22 and the soaking section 23.

[0036] The roasting machine body further includes a drying section 21 , which is arranged between the blast drying section 1 and the preheating section 8 .

[0037] The roasting machine body further includes a third cooling section 26 , which is arranged on the forward direction side of the material flow of the second cooling section 25 .

[0038] Specifically, in the roasting machine body, the blast drying section 1, the drying section 21, the preheating section 8, the roasting section 22, the soaking section 23, the first cooling section 24, the second cooling section 25 and the third cooling section 26 are arranged in sequence along the forward direction of the material flow.

[0039] Among them, the inlet of the first cross air supply duct 16 is connected to the first cooling section 24, and the outlet of the first cross air supply duct 16 is connected to the roasting section 22, so that the high-temperature gas in the first cooling section 24 is discharged to the roasting section 22 through the first cross air supply duct 16.

[0040] Among them, the inlet of the second cross air supply duct 17 is connected to the second cooling section 25, and the outlet of the second cross air supply duct 17 is connected to the uniform heat section 23, so that the high-temperature gas in the second cooling section 25 is discharged to the uniform heat section 23 through the second cross air supply duct 17.

[0041] The first flue gas circulation hot air return duct 3 is provided with a first hot air exchange valve 6 and a first cold air exchange valve 7 .

[0042] By providing a first hot air exchange valve 6 on the first flue gas circulation return hot air duct 3, the flow rate of hot air in the first flue gas circulation return hot air duct 3 can be adjusted. By providing a first cold air exchange valve 7, relatively low-temperature gas can be introduced into the first flue gas circulation return hot air duct 3, thereby lowering the gas temperature in the first flue gas circulation return hot air duct 3. Through the cooperation of the first hot air exchange valve 6 and the first cold air exchange valve 7, the temperature control requirements of the roasting section 22 can be met.

[0043] The first hot air exchange valve 6 and the first cold air exchange valve 7 are regulating valves capable of adjusting the fluid flow rate.

[0044] Among them, one end of the first cold air valve 7 is connected to the first flue gas circulation return hot air duct 3, and the other end is connected to the external air, so that the external ambient air with relatively low temperature can be introduced into the first flue gas circulation return hot air duct 3 to achieve cooling.

[0045] Among them, in the flow direction of the gas in the first flue gas circulation back to the hot air duct 3, the first hot air exchange valve 6 is arranged on the upstream side of the first cold air exchange valve 7, which can achieve a better mixing effect on the hot air.

[0046] The second flue gas circulation hot air duct 11 is provided with a second hot air exchange valve 12 and a second cold air exchange valve 13 .

[0047] By providing a second hot air exchange valve 12 on the second flue gas circulation return hot air duct 11, the flow rate of hot air in the second flue gas circulation return hot air duct 11 can be adjusted. By providing a second cold air exchange valve 13, relatively low-temperature gas can be introduced into the second flue gas circulation return hot air duct 11, thereby lowering the gas temperature in the second flue gas circulation return hot air duct 11. The cooperation between the second hot air exchange valve 12 and the second cold air exchange valve 13 can meet the temperature control requirements of the heat soaking section 23 without adding a burner in the heat soaking section 23.

[0048] During the pellet preparation process, the flue gas from the preheating section 8 can be introduced into the second cooling section 25 through the setting of the second flue gas circulation return hot air duct 11, and the relatively low temperature gas can be introduced into the second flue gas circulation return hot air duct 11 through the setting of the second cold air valve 13. The relatively low temperature gas and the flue gas from the preheating section 8 can enter the second cooling section 25 together, which can ensure the cooling effect while utilizing the waste heat of the flue gas and reducing the amount of flue gas discharged from the system.

[0049] The second hot air exchange valve 12 and the second cold air exchange valve 13 are regulating valves capable of adjusting the fluid flow rate.

[0050] Among them, one end of the second cold air valve 13 is connected to the second flue gas circulation return hot air duct 11, and the other end is connected to the external air, so that the external ambient air with relatively low temperature can be introduced into the second flue gas circulation return hot air duct 11 to achieve cooling.

[0051] Among them, in the flow direction of the gas in the second flue gas circulation back to the hot air duct 11, the second hot air exchange valve 12 is arranged on the upstream side of the second cold air exchange valve 13, which can achieve a better mixing effect on the hot air.

[0052] It can be understood that the material temperature in the second cooling section 25 can reach above 1000°C, and the flue gas temperature of the preheating section 8 led out through the second flue gas circulation hot air duct 11 is about 300°C. The temperature of the mixed gas formed by mixing the flue gas with the external air will be lower, which is quite different from the material temperature. Therefore, mixing the flue gas and the external air as the gas source of the second cooling section 25 can ensure the cooling effect and reduce the amount of flue gas discharged.

[0053] The blast drying section 1 includes a blast drying section upper cover 2, a first flue gas circulation return hot air duct 3 is connected to the blast drying section upper cover 2, a furnace cover dust removal system 4 and a flue gas dehydration system 5 are sequentially arranged on the first flue gas circulation return hot air duct 3 along the flow direction, and a first cooling fan 14 is arranged on the first flue gas circulation return hot air duct 3.

[0054] By connecting the first flue gas circulation return hot air duct 3 with the upper cover 2 of the blast drying section, the hot exhaust gas generated by the blast drying section 1 can be introduced into the first flue gas circulation return hot air duct 3, thereby realizing the directional recovery of the flue gas waste heat in the blast drying section 1, and transporting the waste heat to the first cooling section 24, providing the first cooling section 24 with preheated hot air, optimizing the heat distribution of the cross-air supply flue gas circulation system suitable for the magnetite belt roaster, and improving the overall thermal efficiency of the system.

[0055] By setting up the furnace hood dust removal system 4 and the flue gas dehydration system 5, the flue gas can be purified to prevent dust and moisture from entering the first cooling section 24 and affecting the process. The first cooling fan 14 set on the first flue gas circulation hot air duct 3 provides power for the flue gas circulation, ensuring stable delivery of hot air, realizing the recovery and utilization of the flue gas waste heat in the blast drying section 1, reducing energy waste and improving the thermal efficiency of the system.

[0056] The preheating section 8 includes a preheating section wind box 9 , and the second flue gas circulation hot air return duct 11 is connected to the preheating section wind box 9 . The second flue gas circulation hot air return duct 11 is provided with a flue gas circulation dust removal system 10 and a second cooling fan 15 .

[0057] By connecting the second flue gas circulation return hot air duct 11 with the preheating section wind box 9, the hot exhaust gas collected by the preheating section wind box 9 can be introduced into the second flue gas circulation return hot air duct 11, thereby realizing the directional recovery of the flue gas waste heat in the preheating section 8 and avoiding the heat waste caused by direct discharge.

[0058] By providing the flue gas circulation dust removal system 10, dust in the flue gas can be purified to prevent dust from entering the second cooling section 25 and subsequent process links to affect equipment operation or pellet roasting quality.

[0059] By setting a second cooling fan 15 on the second flue gas circulation hot air return duct 11, power is provided for flue gas circulation, ensuring that the hot exhaust gas from the preheating section 8 is stably transported to the second cooling section 25, optimizing the hot air supply in the cooling section, and improving the system heat utilization rate and process stability.

[0060] A roasting section upper cover is provided at the end of the roasting section 22, and combustion chambers 20 are provided on both sides of the roasting section upper cover. The roasting section 22 also includes a roasting section wind box, and the exhaust port of the first cross air supply duct 16 is connected to the combustion chamber 20 so that the exhaust gas enters the roasting section upper cover through the combustion chamber 20, and passes through the material layer from top to bottom and enters the roasting section wind box.

[0061] This technical solution further provides a connection position for the first cross air supply duct 16, and the exhaust port of the first cross air supply duct 16 is connected to the combustion chamber 20, which can further improve the utilization efficiency of waste heat and promote combustion in the terminal combustion chamber 20. In addition, the hot air delivered by the first cross air supply duct 16 from the first cooling section 24 is heated in the combustion chamber 20 and then enters the upper cover of the roasting section. It then passes through the material layer from top to bottom and enters the roasting section wind box. This ensures that the high-temperature hot air fully contacts the material layer in the roasting section 22, providing a stable high-temperature heat source for pellet roasting, shortening the roasting time and reducing fuel consumption.

[0062] The first cooling section 24 is directly connected to the combustion chamber 20 at the end of the roasting section 22 through the first cross air supply duct 16, which shortens the path, reduces heat loss, and realizes reasonable air supply.

[0063] The soaking section 23 includes a soaking section upper cover and a soaking section wind box. The exhaust port of the second cross air supply duct 17 is connected to the soaking section upper cover so that the exhausted gas passes through the material layer from top to bottom and enters the soaking section wind box.

[0064] By connecting the exhaust port of the second cross air supply duct 17 with the upper cover of the equalizing section, the hot air delivered by the second cooling section 25 is directly introduced into the upper cover of the equalizing section through the second cross air supply duct 17, and passes through the material layer from top to bottom to achieve uniform heat conduction, ensuring that the pellets obtain stable and continuous heat in the equalizing section 23, avoiding the temperature unevenness problem caused by the dispersion of the hot air path, and improving the uniformity of the pellet structure and the roasting quality.

[0065] The outlet hot air of the first cooling section 24 is introduced into the combustion chamber 20 at the end of the roasting section 22 through the first cross air supply duct 16, and the outlet hot air of the second cooling section 25 is introduced into the equalizing section 23 through the second cross air supply duct 17, so as to achieve reasonable air supply through cross air supply.

[0066] A first partition wall 18 is provided between the soaking section 23 and the first cooling section 24. A second partition wall 19 is provided between the first cooling section 24 and the second cooling section 25.

[0067] By arranging the first partition wall 18 between the soaking section 23 and the first cooling section 24, the second partition wall 19 can block the area outside the material conveying path, thereby reducing the escape of heat energy from the soaking section 23 to the first cooling section 24 and further reducing energy consumption.

[0068] By providing the second partition wall 19 , the area outside the material conveying path can be blocked, thereby suppressing the heat energy exchange between the first cooling section 24 and the second cooling section 25 , and further improving the cooling efficiency.

[0069] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0070] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above are merely preferred embodiments of the present application. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. A cross-air supply flue gas circulation system suitable for a magnetite belt roaster, characterized in that: The belt roasting machine comprises a main body, wherein the main body comprises a blast drying section (1), a preheating section (8), a first cooling section (24) and a second cooling section (25) arranged along the forward direction of the material flow; The cross-air supply flue gas circulation system suitable for the magnetite belt roaster also includes a first flue gas circulation return hot air duct (3) and a second flue gas circulation return hot air duct (11); the blast drying section (1) is connected to the first cooling section (24) through the first flue gas circulation return hot air duct (3) to introduce hot air into the first cooling section (24); the preheating section (8) is connected to the second cooling section (25) through the second flue gas circulation return hot air duct (11) to introduce hot air into the second cooling section (25).

2. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 1, characterized in that: The cross-air supply flue gas circulation system suitable for a magnetite belt roaster comprises a roasting section (22) and a soaking section (23) arranged along the forward direction of the material flow, wherein the roasting section (22) and the soaking section (23) are located between the preheating section (8) and the first cooling section (24); The cross-air supply flue gas circulation system suitable for the magnetite belt roaster also includes a first cross-air supply duct (16) and a second cross-air supply duct (17), wherein the first cross-air supply duct (16) is respectively connected to the first cooling section (24) and the roasting section (22), and the second cross-air supply duct (17) is respectively connected to the second cooling section (25) and the soaking section (23).

3. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 1, characterized in that: The first flue gas circulation hot air return duct (3) is provided with a first hot air exchange valve (6) and a first cold air exchange valve (7).

4. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 1, characterized in that: The second flue gas circulation hot air duct (11) is provided with a second hot air exchange valve (12) and a second cold air exchange valve (13).

5. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 1, characterized in that: The blast drying section (1) comprises a blast drying section upper cover (2); the first flue gas circulation return hot air duct (3) is connected to the blast drying section upper cover (2); a furnace cover dust removal system (4) and a flue gas dehydration system (5) are sequentially arranged on the first flue gas circulation return hot air duct (3) along the flow direction; and a first cooling fan (14) is arranged on the first flue gas circulation return hot air duct (3).

6. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 1, characterized in that: The preheating section (8) includes a preheating section wind box (9), the second flue gas circulation hot air return duct (11) is connected to the preheating section wind box (9), and the second flue gas circulation hot air return duct (11) is provided with a flue gas circulation dust removal system (10) and a second cooling fan (15).

7. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 2, characterized in that: A roasting section upper cover is provided at the end of the roasting section (22), and combustion chambers (20) are provided on both sides of the roasting section upper cover. The roasting section (22) also includes a roasting section wind box, and the exhaust port of the first cross air supply duct (16) is connected to the combustion chamber (20) so that the exhausted gas enters the roasting section upper cover through the combustion chamber (20), passes through the material layer from top to bottom, and enters the roasting section wind box.

8. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 2, characterized in that: The heat equalization section (23) includes a heat equalization section upper cover and a heat equalization section wind box, and the exhaust port of the second cross air supply duct (17) is connected to the heat equalization section upper cover so that the exhausted gas passes through the material layer from top to bottom and enters the heat equalization section wind box.

9. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 2, characterized in that: A first partition wall (18) is provided between the heat-sparing section (23) and the first cooling section (24).

10. The cross-air supply flue gas circulation system for a magnetite belt roaster according to claim 1, characterized in that: A second partition wall (19) is provided between the first cooling section (24) and the second cooling section (25).

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