Zone melting micro-positive pressure tail gas dust filtering device and method

Abstract

The invention discloses a zone melting micro-positive pressure tail gas dust filtering device which is V-shaped and comprises a gas inlet section, a dust collecting section and a filtering section which are sequentially connected, a fixing mechanism is arranged between the gas inlet section and the filtering section, the filtering device further comprises a water bath mechanism, and the dust collecting section is immersed in the water bath mechanism; the invention further discloses a zone melting micro-positive pressure tail gas dust filtering method. According to the filtering device, the self structure is designed to be V-shaped and is matched with the water bath mechanism, dust in zone melting micro-positive pressure tail gas is filtered out as much as possible under the combination of triple effects of gravity, water bath condensation and filtering, the filtering effect of the filtering device is improved, and the filtering device is suitable for the technical field of zone melting waste gas treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of regional smelting waste gas treatment, and in particular relates to a regional smelting micro-positive pressure tail gas dust filtering device and method. Background Art

[0002] In the zone melting process of some metals, a slightly positive pressure flowing reducing atmosphere needs to be introduced while heating the metal sample to prevent the sample from being oxidized. The flowing reducing atmosphere can react with other impurity elements to produce compounds, which evaporate and leave the sample with the flowing reducing atmosphere to achieve the desired impurity removal effect.

[0003] At the same time, since some metal raw materials are highly volatile, they will continuously generate metal vapor in their molten state. The metal vapor continues to cool down and condense in the flowing atmosphere to produce fine dust, which enters the exhaust gas treatment system along with the flowing atmosphere. It is easy to block the gas pipeline, causing excessive positive pressure in the equipment, resulting in leakage of gas and impurity volatiles in weak links of air tightness, resulting in safety hazards such as combustion, explosion or leakage of toxic substances. The presence of dust also affects the subsequent treatment effect of the exhaust gas.

[0004] For example, the Chinese invention patent "A method and production device for preparing ultra-high purity tellurium by regional smelting" (publication number CN116121847A) filters the tellurium-containing dust exhaust generated during the regional smelting process by filling asbestos in the scrubbing bottle. However, the asbestos has large gaps, and most of the space in the scrubbing bottle is filled with asbestos, resulting in poor filtering effect, low dust holding capacity, high risk of clogging, and difficult installation and disassembly of the structure. In addition, asbestos poses a great health hazard to operators, and the metal dust filtered by asbestos is not easy to separate again. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing a dust filtration device for zone smelting exhaust gas at a slightly positive pressure. This device utilizes a V-shaped structure and a water bath mechanism to filter out as much dust as possible from zone smelting exhaust gas at a slightly positive pressure by combining gravity, water bath condensation, and filtration, thus addressing the poor filtration performance of existing filtration devices.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a zone smelting micro-positive pressure exhaust gas dust filtering device, characterized in that the filtering device is V-shaped, including an air intake section, a dust collecting section and a filtering section connected in sequence, a fixing mechanism is provided between the air intake section and the filtering section, and the filtering device also includes a water bath mechanism, and the dust collecting section is immersed in the water bath mechanism.

[0007] The above-mentioned regional smelting micro-positive pressure exhaust gas dust filtering device is characterized in that the direction of the filtering section is vertically upward, the angle between the air intake section and the filtering section is 15°~35°, and the length ratio of the air intake section and the filtering section is 1:2~4.

[0008] The above-mentioned zone smelting micro-positive pressure exhaust gas dust filtration device is characterized in that the temperature of the water bath mechanism is set to 0°C~15°C, the end of the air inlet section close to the dust collecting section is immersed in the water bath mechanism, and the immersion length is not greater than 2 / 3 of the length of the air inlet section.

[0009] The above-mentioned regional smelting micro-positive pressure exhaust gas dust filtering device is characterized in that the air inlet section includes an air inlet section shell, an air inlet pipe main body extending into the air inlet section shell, and an air inlet section sealing cover at the top of the air inlet section shell, and the air outlet of the air inlet pipe main body is a multi-way outlet; the multi-way outlet has a plurality of air outlet circular pipes vertically distributed along the axial direction.

[0010] The above-mentioned regional smelting micro-positive pressure exhaust gas dust filtering device is characterized in that an air intake pipe splicing section is provided between the air inlet and the air outlet of the air intake pipe main body, and the air intake pipe splicing section is composed of a pair of pagoda head interfaces and a hose outside the pagoda head interface. The air outlet circular pipe is four-fold symmetrically distributed, and the length of the air outlet circular pipe is 1 / 2 to 3 / 4 of the length of the air intake section outer shell.

[0011] The above-mentioned regional smelting micro-positive pressure exhaust gas dust filtering device is characterized in that the filter section includes a filter section shell, an outlet pipe main body extending into the filter section shell and a filter section sealing cover at the top of the filter section shell, and the outlet pipe main body is provided with an outlet filter pipe with an external filter bag near one end of the dust collecting section, and the outlet filter pipe includes an outlet filter pipe inlet section, an outlet filter pipe sedimentation section and a bottom cover connected in sequence, and a plurality of circular holes are opened on the outlet filter pipe inlet section.

[0012] The above-mentioned regional smelting micro-positive pressure exhaust gas dust filtering device is characterized in that the outlet pipe main body and the outlet filter pipe are connected through an outlet pipe splicing section, and the outlet pipe splicing section is composed of a pair of pagoda head interfaces and a hose outside the pagoda head interface.

[0013] The above-mentioned regional smelting micro-positive pressure exhaust gas dust filtering device is characterized in that the length of the outlet filter tube is 1 / 2 to 3 / 4 of the length of the filter section shell, the circular holes are distributed four times symmetrically along the axis on the air inlet section of the outlet filter tube, and the length ratio of the sedimentation section of the outlet filter tube to the air inlet section of the outlet filter tube is 1 / 4 to 1 / 2.

[0014] The above-mentioned zone smelting micro-positive pressure exhaust gas dust filtering device is characterized in that the micro-positive pressure value of the exhaust gas that can be treated by the filtering device is 0.005MPa~0.015MPa, and the flow rate of the exhaust gas is 0.1L / min~4L / min.

[0015] The present invention also discloses a method for filtering dust from zone smelting tail gas with slight positive pressure, which is characterized in that the method is performed using the above-mentioned filtering device and comprises the following steps: Step 1: Connect the exhaust gas outlet of the zone smelting to the inlet of the air intake section through a hose, then connect the outlet of the filtration section to the subsequent exhaust gas treatment process, and then press the filter device into the water bath mechanism through a fixing mechanism, and adjust the temperature of the water bath mechanism; Step 2: Start the regional smelting operation and pass the continuously generated dust-containing exhaust gas into the filter device. After the regional smelting operation is completed, replace the dust-containing exhaust gas with inert gas and continue to pass it into the filter device for 0.5h~2h. After replacing the residual exhaust gas inside, stop passing the inert gas and disassemble and clean the filter device.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The filtering device of the present invention realizes multi-stage treatment of dust-containing tail gas by designing its own structure into a V shape and cooperating with a water bath mechanism, utilizing the triple effects of gravity, water bath condensation and filtration, and filters out the dust in the regional smelting slightly positive pressure tail gas as much as possible.

[0017] 2. The present invention designs a filtering device with a V-shaped structure and designs the dust collecting section as a V-shaped turning point, forcing the dust-containing exhaust gas to slow down after passing through the dust collecting section, and enables the filter section to use gravity to make the dust-containing exhaust gas partially settle again during the rising process, and then cooperate with the exhaust filter tube and filter bag for filtration; the residual dust in the exhaust gas after filtration can settle again in the settling section of the exhaust filter tube, further improving the filtration effect, and the gas flow resistance is small, which greatly reduces the risk of blockage in the exhaust gas discharge path in the middle, significantly reduces the leakage risk of the regional smelting exhaust gas filtration process, and improves the safety of the atmosphere regional smelting process; and, by designing the dust collecting section to cooperate with the water bath mechanism for cooling, the residual metal vapor in the exhaust gas is condensed, agglomerated and settled, and the dust collecting section is used to collect the settled metal dust, thereby improving the dust holding capacity of the filter device, reducing the filtration burden of the subsequent stage, and extending the cleaning and replacement cycle of the filter device.

[0018] 3. The present invention provides multiple outlets to blow the dust-laden tail gas vertically toward the inner surface of the air intake section housing, thereby slowing down the dust-laden tail gas for initial sedimentation and avoiding the dust-laden tail gas directly flushing the dust collected in the dust collecting section and generating secondary dust.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the filtering device of the present invention.

[0021] Figure 2 It is a structural schematic diagram of the air intake section, dust collection section and filtration section of the present invention.

[0022] Figure 3 for Figure 2 Enlarged view of point A.

[0023] Figure 4 for Figure 2 Enlarged view of point B.

[0024] Figure 5 Schematic diagram of the structure of the air outlet filter tube of the present invention.

[0025] Description of reference numerals: 1—air inlet section; 1-1—air inlet section housing; 1-2—air inlet pipe body; 1-3—air inlet pipe splicing section; 1-4—multi-way outlet; 1-5—air inlet section sealing cover; 1-6—blind end; 2—dust collecting section; 3—filter section; 3-1—filter section housing; 3-2—air outlet pipe body; 3-3—air outlet pipe splicing section; 3-4—air outlet filter pipe; 3-4-1—air inlet section of air outlet filter pipe; 3-4-2—air outlet filter pipe sedimentation section; 3-4-3—bottom cover; 3-5—filter bag; 3-6—filter section sealing cover; 4—fixing mechanism; 5—water bath mechanism. DETAILED DESCRIPTION

[0026] Example 1 like Figure 1 As shown, the filtering device of this embodiment is V-shaped, including an air intake section 1, a dust collecting section 2 and a filtering section 3 connected in sequence, a fixing mechanism 4 is provided between the air intake section 1 and the filtering section 3, and the filtering device also includes a water bath mechanism 5, and the dust collecting section 2 is immersed in the water bath mechanism 5.

[0027] In actual use, in this embodiment, an air intake section 1, a dust collecting section 2 and a filter section 3 are provided to form a V-shape, so that the dust-containing tail gas entering the air intake section 1 is initially settled in the dust collecting section 2 under the action of gravity, and then enters the filter section 3 for filtration; at the same time, the dust collecting section 2 is immersed in a water bath mechanism 5, so that the metal vapor in the dust-containing tail gas condenses, agglomerates and settles in the dust collecting section 2; a fixing mechanism 4 is provided to control the dust collecting section 2 to be completely immersed below the liquid level of the water bath mechanism 5 to avoid floating, and at the same time, it can support and strengthen it, making the dust collecting section 2 at the bend less likely to break. Preferably, the fixing mechanism 4 of this embodiment is a groove reinforcement rib, which can be pressed down and fixed by simply applying a stick-shaped weight or tying a rope.

[0028] Furthermore, if Figure 1 As shown, in this embodiment, the direction of the filter section 3 is vertically upward, the angle between the air intake section 1 and the filter section 3 is 15°~35°, and the length ratio of the air intake section 1 to the filter section 3 is 1:2~4.

[0029] In actual use, in this embodiment, by setting the direction of the filter section 3 to be vertically upward, the sedimentation path of the dust-containing tail gas that has passed through the water bath cooling of the dust collection section 2 is increased. At this time, since the filter device is V-shaped, the air intake section 1 is set at an angle, which can cause the tail gas entering the air intake section 1 to slow down after contacting the inner wall of the air intake section 1. By setting the angle between the air intake section 1 and the filter section 3 to 15°~35°, it is avoided that the angle is too large to affect the sedimentation effect of the dust; it is also avoided that the angle is too small to be inconvenient to manufacture and process, and it is not easy to fix it with the water bath mechanism 5. By setting the length ratio of the air intake section 1 and the filter section 3 to 1:2~4, the height of the air intake section 1 is relatively low, which is convenient for connection with the gas path of the regional smelting tail gas outlet section, while the filter section 3 is higher to fully realize the gravity sedimentation effect and provide a sufficiently long filtering space, thereby enhancing the dust filtration effect and extending the service life of the filter assembly.

[0030] Furthermore, if Figure 1 As shown, in this embodiment, the temperature of the water bath mechanism 5 is set to 0°C~15°C, and one end of the air intake section 1 close to the dust collecting section 2 is immersed in the water bath mechanism 5, and the immersed length is not greater than 2 / 3 of the length of the air intake section 1.

[0031] In actual use, in this embodiment, the temperature of the water bath mechanism 5 is controlled so that the metal vapor in the dust-containing exhaust gas can be condensed and agglomerated; by partially immersing the air intake section 1 in the water bath mechanism 5, the length of the cooling zone of the metal vapor is extended, and the probability of metal vapor cooling is improved; at the same time, the length of the air intake section 1 partially immersed in the water bath mechanism 5 is controlled to be no more than 2 / 3, so that the air intake section 1 cannot be completely buried to prevent accidents. For example, a power outage of the equipment causes the regional smelting process to stop, and a sharp drop in temperature causes negative pressure to be generated in the device, so that water is sucked back into the filter device along the air intake section sealing cover 1-5 or the air intake pipe main body 1-2, causing danger.

[0032] Furthermore, if Figure 2 As shown, in this embodiment, the air intake section 1 includes an air intake section shell 1-1, an air intake pipe body 1-2 extending into the air intake section shell 1-1, and an air intake section sealing cover 1-5 at the top of the air intake section shell 1-1. The air outlet of the air intake pipe body 1-2 is a multi-way outlet 1-4; the multi-way outlet 1-4 has a plurality of air outlet circular tubes vertically distributed along the axial direction.

[0033] In actual use, in this embodiment, an air inlet pipe body 1-2 is provided to connect the exhaust outlet of the regional smelting, so that the dust-containing exhaust gas enters the filtering device; an air inlet section housing 1-1 and an air inlet section sealing cover 1-5 are provided to isolate the air inlet section 1 from the external environment; and the air outlet of the air inlet pipe body 1-2 is provided as a multi-way outlet 1-4 to disperse the exhaust gas and reduce the exhaust gas velocity. The multi-way outlet 1-4 is a plurality of air outlet circular pipes perpendicular to the axial direction. The dust-containing exhaust gas is sprayed toward the inner wall of the air inlet section housing 1-1, further reducing the velocity and facilitating dust sedimentation. It should be noted that the blind end 1-6 of the multi-way outlet 1-4 is sealed to prevent the exhaust gas from directly flushing the dust already collected in the dust collecting section 2 and generating secondary dust.

[0034] Preferably, in this embodiment, the air intake section sealing cover 1-5 is threadedly connected to the air intake section housing 1-1, and a sealing gasket is installed, and the thread surface is coated with vacuum silicone grease, which can further enhance the air tightness; the air intake section housing 1-1, the dust collecting section 2 and the filter section housing 3-1 are made of PMMA (polymethyl methacrylate) material. PMMA material has good plasticity and is not easy to break during use. It is easy to process, low in cost and transparent, and it is easy to observe the filtering conditions at any time and promptly discover problems inside the device.

[0035] Furthermore, if Figure 2 and Figure 3 As shown, in this embodiment, an air intake pipe splicing section 1-3 is provided between the air inlet and the air outlet of the air intake pipe main body 1-2, and the air intake pipe splicing section 1-3 is composed of a pair of pagoda head interfaces and a hose outside the pagoda head interfaces; the air outlet circular pipe is four-fold symmetrically distributed, and the length of the air outlet circular pipe is 1 / 2~3 / 4 of the length of the air intake section shell 1-1.

[0036] In actual use, in this embodiment, an air intake pipe splicing section 1-3 is set between the air inlet and the air outlet of the air intake pipe main body 1-2, which is convenient for disassembly and cleaning; the risk of dust blockage can be reduced by setting the air outlet circular pipe to a four-fold symmetrical distribution, and the four-fold symmetrical distribution is a 90° distribution between each air outlet circular pipe on the same circumference; by setting the length of the air outlet circular pipe to 1 / 2~3 / 4 of the length of the air intake section shell 1-1, a part of the space in the pipe is reserved for the initial sedimentation and buffering of dust.

[0037] Furthermore, if Figure 2As shown, in this embodiment, the filter section 3 includes a filter section housing 3-1, an air outlet pipe main body 3-2 extending into the filter section housing 3-1, and a filter section sealing cover 3-6 at the top of the filter section housing 3-1. The air outlet pipe main body 3-2 is provided with an air outlet filter pipe 3-4 with an external filter bag 3-5 at one end near the dust collecting section 2. The air outlet filter pipe 3-4 includes an air outlet filter pipe inlet section 3-4-1, an air outlet filter pipe sedimentation section 3-4-2 and a bottom cover 3-4-3 connected in sequence. A number of circular holes are opened on the air outlet filter pipe inlet section 3-4-1.

[0038] In actual use, this embodiment is provided with a filter section housing 3-1 and a filter section sealing cover 3-6 to isolate the filter section 3 from the external environment. An outlet pipe body 3-2 having an outlet filter pipe 3-4 is provided, and a filter bag 3-5 is provided outside the outlet filter pipe 3-4 to filter dust-laden exhaust gas. Dust filtered by the filter bag 3-5 can be gathered into the dust collection section 2 under the action of gravity, thereby extending the cleaning and replacement cycle of the filter bag 3-5. Furthermore, by providing an outlet filter pipe settling section 3-4-2 at the bottom of the outlet filter pipe inlet section 3-4-1 and a bottom cover 3-4-3 at the lower end of the outlet filter pipe settling section 3-4-2, the rate at which the filtered exhaust gas enters the circular hole is reduced, and the residual dust settles again and gathers in the bottom cover 3-4-3.

[0039] Preferably, in this embodiment, the filter bag 3-5 is made of polypropylene woven cloth, and the pore diameter is 10μm~100μm, and the thickness is 3mm~15mm, which can effectively filter the dust-containing exhaust gas; the filter bag 3-5 is fastened to the top of the air inlet section 3-4-1 of the outlet filter pipe by an elastic rope; the bottom cover 3-4-3 and the sedimentation section 3-4-2 of the outlet filter pipe are threadedly connected for easy disassembly; the filter section sealing cover 3-6 is threadedly connected to the filter section housing 3-1, and a sealing gasket is installed, and the thread surface is coated with vacuum silicone grease to further enhance the air tightness.

[0040] Furthermore, if Figure 2 and Figure 4 As shown, in this embodiment, the air outlet pipe main body 3-2 and the air outlet filter pipe 3-4 are connected through the air outlet pipe splicing section 3-3, and the air outlet pipe splicing section 3-3 is composed of a pair of pagoda head interfaces and a hose outside the pagoda head interface.

[0041] In actual use, in this embodiment, the air inlet pipe splicing section 1-3 is provided between the air outlet pipe body 3-2 and the air outlet filter pipe 3-4, so as to facilitate disassembly and cleaning.

[0042] Furthermore, if Figure 2As shown, in this embodiment, the length of the outlet filter tube 3-4 is 1 / 2 to 3 / 4 of the length of the filter section housing 3-1, the circular holes are symmetrically distributed four times along the axis on the outlet filter tube inlet section 3-4-1, and the length ratio of the outlet filter tube sedimentation section 3-4-2 to the outlet filter tube inlet section 3-4-1 is 1 / 4 to 1 / 2.

[0043] In actual use, in this embodiment, by setting the length of the outlet filter tube 3-4 to 1 / 2 to 3 / 4 of the length of the filter section housing 3-1, sufficient space can be reserved for gravitational settling of dust during the outlet filtration stage, thereby improving the settling effect. By arranging circular holes in the outlet filter tube inlet section 3-4-1, which are symmetrically distributed four times along the axis, the risk of dust blockage can be significantly reduced, allowing exhaust gas to enter the outlet filter tube inlet section 3-4-1 more evenly. The four-fold symmetrical distribution means that the circular holes on the same circumference are distributed at 90 degrees. By setting the length ratio of the outlet filter tube settling section 3-4-2 to the outlet filter tube inlet section 3-4-1 to 1 / 4 to 1 / 2, sufficient space can be reserved for gravitational settling of dust within the outlet filter tube 3-4, while also providing space for collecting settled dust. Preferably, in this embodiment, the diameter of the circular holes is 1 / 4 to 1 / 2 of the diameter of the outlet filter tube inlet section 3-4-1.

[0044] Furthermore, in this embodiment, the micro-positive pressure value of the tail gas that can be processed by the filtering device is 0.005MPa~0.015MPa, and the flow rate of the tail gas is 0.1L / min~4L / min.

[0045] In actual use, the tail gas micro-positive pressure value and tail gas flow rate range that can be processed by the filter device in this embodiment are the common ranges of the micro-positive pressure tail gas generated by the zone smelting process.

[0046] Example 2 The method for filtering exhaust gas dust using a filtering device in this embodiment includes the following steps: Step 1: Connect the exhaust gas outlet of the zone smelting to the air inlet of the air inlet pipe body 1-2 through a hose, and then connect the outlet of the air outlet pipe body 3-2 to the subsequent exhaust gas treatment process. Then, press the filter device into the water bath mechanism 5 through the fixing mechanism 4, control the length of the air inlet section 1 immersed in the liquid surface to 2 / 3 of the length of the air inlet section 1, and adjust the temperature of the water bath mechanism 5 to 0°C~15°C; the fixing mechanism 4 is a groove reinforcement rib, and a stick-shaped weight or a binding rope is applied to the groove reinforcement rib to press down and fix the filter device; Step 2: Start the regional smelting operation and pass the continuously generated dust-containing tail gas into the filter device. After the regional smelting operation is completed, replace the dust-containing tail gas with nitrogen at a flow rate of 1L / min~4L / min and continue to pass it into the filter device for 0.5h~2h. After replacing the residual tail gas inside, stop passing nitrogen, collect the deposited dust after disassembly, and clean the filter device with water; the residual tail gas is hydrogen.

[0047] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A zone smelting micro-positive pressure tail gas dust filtration device, characterized in that: The filtering device is V-shaped and comprises an air intake section (1), a dust collection section (2) and a filtering section (3) connected in sequence. A fixing mechanism (4) is provided between the air intake section (1) and the filtering section (3). The filtering device further comprises a water bath mechanism (5), and the dust collection section (2) is immersed in the water bath mechanism (5).

2. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 1 is characterized in that: The direction of the filtering section (3) is vertically upward, the angle between the air intake section (1) and the filtering section (3) is 15° to 35°, and the length ratio of the air intake section (1) to the filtering section (3) is 1:2 to 4.

3. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 1 is characterized in that: The temperature of the water bath mechanism (5) is set to 0°C to 15°C, and one end of the air intake section (1) close to the dust collection section (2) is immersed in the water bath mechanism (5), and the immersed length is no more than 2 / 3 of the length of the air intake section (1).

4. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 1 is characterized in that: The air intake section (1) comprises an air intake section housing (1-1), an air intake pipe body (1-2) extending into the air intake section housing (1-1), and an air intake section sealing cover (1-5) at the top end of the air intake section housing (1-1); the air outlet of the air intake pipe body (1-2) is a multi-way outlet (1-4); the multi-way outlet (1-4) has a plurality of air outlet circular tubes vertically distributed along the axial direction.

5. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 4 is characterized in that: An air intake pipe splicing section (1-3) is provided between the air inlet and the air outlet of the air intake pipe main body (1-2), and the air intake pipe splicing section (1-3) is composed of a pair of pagoda head interfaces and a hose outside the pagoda head interfaces; the air outlet circular pipes are distributed four-fold symmetrically, and the length of the air outlet circular pipes is 1 / 2 to 3 / 4 of the length of the air intake section shell (1-1).

6. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 1 is characterized in that: The filter section (3) comprises a filter section housing (3-1), an air outlet pipe body (3-2) extending into the filter section housing (3-1), and a filter section sealing cover (3-6) at the top of the filter section housing (3-1); an air outlet filter pipe (3-4) with a filter bag (3-5) externally sleeved thereon is provided at one end of the air outlet pipe body (3-2) close to the dust collecting section (2); the air outlet filter pipe (3-4) comprises an air outlet filter pipe inlet section (3-4-1), an air outlet filter pipe settling section (3-4-2), and a bottom cover (3-4-3) connected in sequence; and a plurality of circular holes are provided on the air outlet filter pipe inlet section (3-4-1).

7. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 6, characterized in that: The air outlet pipe main body (3-2) and the air outlet filter pipe (3-4) are connected via an air outlet pipe splicing section (3-3), and the air outlet pipe splicing section (3-3) is composed of a pair of pagoda head interfaces and a hose outside the pagoda head interfaces.

8. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 6, characterized in that: The length of the outlet filter tube (3-4) is 1 / 2 to 3 / 4 of the length of the filter section housing (3-1); the circular holes are distributed four times symmetrically along the axis of the outlet filter tube inlet section (3-4-1); and the length ratio of the outlet filter tube settling section (3-4-2) to the outlet filter tube inlet section (3-4-1) is 1 / 4 to 1 / 2.

9. The zone smelting micro-positive pressure tail gas dust filtration device according to claim 1, characterized in that: The micro-positive pressure value of the tail gas that can be processed by the filtering device is 0.005MPa~0.015MPa, and the flow rate of the tail gas is 0.1L / min~4L / min.

10. A method for filtering dust from zone smelting tail gas with slight positive pressure, characterized in that: The method is carried out using the filtration device according to any one of claims 1 to 9, comprising the following steps: Step 1: Connect the tail gas outlet of the zone smelting to the inlet of the air inlet section (1) through a hose, then connect the outlet of the filter section (3) to the subsequent tail gas treatment process, and then press the filter device into the water bath mechanism (5) through the fixing mechanism (4), and adjust the temperature of the water bath mechanism (5); Step 2: Start the regional smelting operation and pass the continuously generated dust-containing exhaust gas into the filter device. After the regional smelting operation is completed, replace the dust-containing exhaust gas with inert gas and continue to pass it into the filter device for 0.5h~2h. After replacing the residual exhaust gas inside, stop passing the inert gas and disassemble and clean the filter device.

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