Temperature regulation and treatment methods for furnace gas

Abstract

The present invention discloses a temperature regulation method and a treatment method for discharged furnace gas, which solves the technical problems of low purity of As2O3 products and pipeline blockage in the prior art. The temperature regulation method for discharged furnace gas includes the following steps: obtaining a first gas, the first gas being obtained by heating compressed air; obtaining a second gas, the second gas being obtained by heating the first gas; obtaining a third gas, the third gas being obtained by heating the first gas; the temperature of the third gas being adapted to a target temperature of the discharged furnace gas; the temperature of the second gas being greater than the temperature of the third gas; using the third gas to insulate the pipelines and filters on the flow path before desublimation or liquefaction of the gas in the discharged furnace gas, and controlling the mixing ratio of the first gas, the second gas, and the discharged furnace gas so that the mixed mixture flows on the flow path at the target temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of furnace gas, in particular to the technical field of high-arsenic-tin smoke gas, and specifically to a temperature regulation method and a treatment method of the furnace gas. Background Art

[0002] The current process for volatilizing high-arsenic tin dust and recovering As₂O₃ products using a DC furnace involves mixing measured high-arsenic tin dust (slag) with quartz sand and coke powder, then feeding it into the DC furnace via a screw feeder. By controlling the negative pressure and temperature within the DC furnace, the majority of the oxidized arsenic is volatilized as gaseous arsenic oxides. Arsenic present in the material as arsenate is thermally reduced by the coke powder to form volatile gaseous arsenic oxides. These gaseous arsenic oxides then flow through the airflow into a gravity dust collector, where they settle and condense to produce the As₂O₃ product. Arsenic-containing furnace gases that have not yet settled continue to enter a baghouse dust collector. After dust removal by the baghouse, the gases enter the desulfurization section for treatment and are then discharged. By controlling the volatilization of tin during this process, the valuable metallic tin is concentrated in the slag.

[0003] The main disadvantages of this process are:

[0004] (1) In the gravity dust collector and bag dust collector, a large amount of dust is adsorbed on the As2O3 product, resulting in an As2O3 purity of only 90-92%, which does not meet the purity requirements of related products; in addition, the dust still contains a large amount of tin, and the cost of subsequent purification is high.

[0005] (2) Due to the large temperature fluctuations of the furnace gas, the furnace gas may condense and precipitate before entering the gravity dust collector, causing pipeline blockage. Summary of the Invention

[0006] The main purpose of the present invention is to provide a temperature regulation method and a treatment method for furnace gas, as well as a treatment device and a treatment system for furnace gas, so as to solve the technical problems of low purity of As2O3 products and pipeline blockage in the prior art.

[0007] In order to achieve the above-mentioned object, according to a first aspect of the present invention, the following two methods for regulating the temperature of furnace gas are provided.

[0008] The first method for regulating the temperature of the furnace gas discharged from the furnace is as follows: the furnace gas discharged from the furnace contains dust and gas that can be condensed or liquefied, and the temperature regulating method is used to regulate the temperature of the furnace gas discharged from the furnace temperature to the target temperature, wherein the target temperature is higher than the condensation temperature or the liquefaction temperature and lower than the tolerance temperature limit of the filter element in the filter for recovering the dust; the temperature regulating method includes the following steps: obtaining a first gas, which is obtained by heating compressed air; obtaining a second gas, which is obtained by heating the first gas; obtaining a third gas, which is obtained by heating the first gas; the temperature of the third gas is adapted to the target temperature of the furnace gas discharged from the furnace; the temperature of the second gas is greater than the temperature of the third gas; in the flow path before the gas in the furnace gas is condensed or liquefied, the third gas is used to insulate the pipes and filters on the flow path, and the mixed ratio of the first gas, the second gas and the furnace gas discharged is controlled to make the mixed mixture flow on the flow path at the target temperature.

[0009] The second method for regulating the temperature of the furnace gas is as follows: the furnace gas contains dust and gaseous As2O3, the furnace gas has a discharge temperature of 200-660°C, and the temperature regulating method is used to regulate the temperature of the furnace gas from the discharge temperature to a target temperature, wherein the target temperature is higher than the desublimation temperature of the gaseous As2O3 and lower than the tolerance temperature limit of the filter element in the filter for recovering the dust; the temperature regulating method comprises the following steps: obtaining a first gas, which is obtained by heating compressed air; the temperature of the first gas is 320-370°C; obtaining a second gas, which is The second gas is obtained by heating the first gas; the temperature of the second gas is 400-450°C; a third gas is obtained, and the third gas is obtained by heating the first gas; the temperature of the third gas is 350-450°C; the temperature of the third gas is adapted to the target temperature of the out-of-furnace gas; on the flow path before desublimation treatment of gaseous As2O3 in the out-of-furnace gas, the third gas is used to insulate the pipes and filters on the flow path, and then the mixed ratio of the first gas, the second gas and the out-of-furnace gas is controlled to make the mixed mixture flow on the flow path at the target temperature.

[0010] As a further improvement of the first aspect of the present invention, the target temperature and the temperature of the third gas are 350-400°C, the temperature of the first gas is 320-350°C, and the temperature of the second gas is 400-420°C.

[0011] As a further improvement to the first aspect of the present invention, the filter element is back-blown and cleaned with the first gas.

[0012] As a further improvement of the first aspect of the present invention, the furnace gas is the furnace gas generated by treating arsenic-tin smoke, quartz sand and coke powder in a direct current furnace, a rotary kiln or a converter.

[0013] As a further improvement to the first aspect of the present invention, a PLC control system is used to control the mixing ratio of the first gas, the second gas and the furnace gas so that the mixed mixture flows on the flow path at a target temperature.

[0014] In order to achieve the above object, according to a second aspect of the present invention, a method for treating furnace gas is provided, and the technical solution is as follows:

[0015] A method for treating furnace gas, wherein the furnace gas is the furnace gas generated by treating arsenic-tin smoke, quartz sand and coke powder in a direct current furnace, a rotary kiln or a converter, the furnace gas contains dust and gaseous As2O3, and the furnace temperature of the furnace gas is 200-660°C. The treatment method comprises the following steps: using the temperature adjustment method described in the first aspect above to adjust the temperature of the furnace gas from the furnace temperature to 350-450°C and filtering the obtained gas to be filtered to obtain a first dust-free gas; performing desublimation treatment on the first dust-free gas to condense the gaseous As2O3 in the first dust-free gas into solid As2O3 to obtain desublimation gas containing solid As2O3; and performing gas-solid separation treatment on the desublimation gas to obtain an As2O3 product and a second dust-free gas.

[0016] As a further improvement of the second aspect of the present invention, the desublimation treatment adopts gas-to-gas contact heat exchange, the cold source is compressed air at room temperature, and the temperature of the obtained desublimation gas is 50-100°C.

[0017] As a further improvement to the second aspect of the present invention, a portion of the solid As2O3 is collected during the desublimation process.

[0018] As a further improvement of the second aspect of the present invention, the second dust-free gas is further subjected to desulfurization treatment; the desulfurized gas is discharged through a chimney.

[0019] In order to achieve the above-mentioned object, according to the third aspect of the present invention, a furnace gas processing device is provided, and the technical solution is as follows:

[0020] A processing device for furnace gas discharged from the furnace, wherein the furnace gas contains dust and gas that is easily condensed or liquefied, and the processing device includes a filter and an air inlet pipe and an air outlet pipe connected to the filter, wherein the filter element in the filter is a metal porous film; the processing device also includes a temperature regulating component, and the temperature regulating component is used to regulate the temperature of the furnace gas discharged from the furnace discharge temperature to a target temperature, and the target temperature is higher than the condensation temperature or the liquefaction temperature and lower than the tolerance temperature limit of the filter element in the filter; the temperature regulating component includes: a first-level heating mechanism, which is used to heat the compressed air into a first gas and pass the first gas into the air inlet pipe; a second-level heating mechanism, which is used to heat the first gas into a second gas and pass the second gas into the air inlet pipe; a third-level heating mechanism, which is used to heat the first gas into a third gas and allow the third gas to insulate the filter, the air inlet pipe and the air outlet pipe; a temperature detection mechanism, which is used to detect the temperature of the gas to be filtered in the air inlet pipe and / or the temperature of the first dust-free gas in the air outlet pipe.

[0021] As a further improvement of the third aspect of the present invention, the first-level heating mechanism includes a first-level heater, a first pipe and a first valve, the first pipe connects the first-level heater and the air inlet pipe, and the first valve is arranged on the first pipe; the second-level heating mechanism includes a second-level heater, a second pipe and a second valve, the second pipe connects the second-level heater and the air inlet pipe, and the second valve is arranged on the second pipe; the third-level heating mechanism includes a jacket and a first fan, the jacket is arranged on the outside of the filter, the air inlet pipe and the air outlet pipe, and the first fan draws the third gas to flow in the jacket.

[0022] As a further improvement of the third aspect of the present invention, the processing equipment further includes a PLC control system for controlling the opening and closing of the first valve and the second valve according to the detection value of the temperature detection mechanism.

[0023] As a further improvement of the third aspect of the present invention, the air inlet pipe is connected to the air outlet of the DC furnace, the rotary kiln or the converter.

[0024] As a further improvement of the third aspect of the present invention, the processing equipment further includes a back-blowing mechanism for back-blowing and cleaning the filter element, and the back-blowing mechanism includes a back-blowing pipe connected to the primary heating mechanism.

[0025] As a further improvement of the third aspect of the present invention, the processing device includes two filters connected in parallel.

[0026] In order to achieve the above-mentioned object, according to a fourth aspect of the present invention, a system for processing furnace gas is provided, and the technical solution is as follows:

[0027] A processing system for discharged furnace gas, wherein the discharged furnace gas contains dust and gaseous As2O3, and the discharged furnace gas has a discharge temperature of 200-660°C, the processing system comprising: the discharged furnace gas processing equipment described in the third aspect above; a gas to be filtered formed by mixing the first gas, the second gas and the discharged furnace gas, and filtering the gas through a filter to obtain a first dust-free gas; a condensation unit, wherein the first dust-free gas is mixed with compressed air in the condensation unit to condense the gaseous As2O3 into solid As2O3, thereby obtaining a sublimation gas containing solid As2O3; and a recovery unit, wherein the recovery unit performs gas-solid separation on the sublimation gas to obtain an As2O3 product and a second dust-free gas.

[0028] As a further improvement of the fourth aspect of the present invention, the processing system further includes a desulfurization unit for desulfurizing the second dust-free gas; the processing system further includes a second fan and a chimney.

[0029] As a further improvement of the fourth aspect of the present invention, the condensing unit includes a gravity dust collector.

[0030] As a further improvement of the fourth aspect of the present invention, the recovery unit includes a bag dust collector.

[0031] It has been verified that the present invention has the following advantages:

[0032] (1) The temperature of the furnace gas is adjusted by temperature regulation methods and processing equipment so that the furnace gas is always maintained at the target temperature before entering the gravity dust collector, so that As2O3 always exists in gaseous form to prevent pipeline blockage.

[0033] (2) Use a filter that can withstand high temperatures to filter the furnace gas, so that the gaseous As2O3 is separated from the dust, and the As2O3 is condensed in a dust-free environment, which significantly improves the purity of As2O3.

[0034] (3) The dust intercepted by the high-temperature filter can be further returned to the furnace body for reaction, thereby fully recovering the tin and arsenic elements in the dust and maximizing the utilization of resources.

[0035] As can be seen, the present invention has a simple structure and process, is easy to implement and control, and is low-cost. It can be used by simply modifying existing processes and equipment. It significantly improves product purity, fully recovers tin and arsenic, and can generate very significant economic benefits, thus possessing strong practicality. Clearly, in addition to its application in systems for treating high-arsenic-tin dust, the temperature regulation method, treatment method, treatment equipment, and treatment system of the present invention are also applicable to other scenarios, particularly those requiring adjustment of the temperature of furnace gas leaving the furnace.

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings that constitute part of this invention are intended to assist in understanding the invention. The contents provided in the drawings and their related descriptions in the present invention may be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 It is a structural schematic diagram of an embodiment of the processing equipment for furnace gas of the present invention.

[0039] Figure 2 It is a structural schematic diagram of an embodiment of a system for processing furnace gas according to the present invention.

[0040] The relevant marks in the above drawings are:

[0041] 110-first stage heater, 120-second stage heater, 130-third stage heater, 131-first fan, 200-filter, 300-gravity dust collector, 400-bag dust collector, 500-power wave scrubber, 610-second fan, 620-chimney. DETAILED DESCRIPTION

[0042] The present invention is described clearly and completely below with reference to the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be noted that:

[0043] The technical solutions and technical features provided in each part of the present invention, including the following description, may be combined with each other unless there is any conflict.

[0044] In addition, the embodiments of the present invention described below are generally only part of the embodiments of the present invention, rather than all of the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts should fall within the scope of protection of the present invention.

[0045] Regarding the terms and units in the present invention: The terms "include", "have" and any variations thereof in the description and claims of the present invention and the related parts are intended to cover non-exclusive inclusions.

[0046] The temperature regulation method of the furnace gas of the present invention is mainly, but not limited to, applicable to the treatment of furnace gas containing dust and condensable or liquefiable gas. The technical effect to be achieved is to regulate the temperature of the furnace gas from the furnace outlet temperature to a target temperature, wherein the target temperature is higher than the condensation temperature or liquefaction temperature and lower than the temperature tolerance limit of the filter element in the filter 200 for recovering the dust. One embodiment includes the following steps:

[0047] Obtaining a first gas, where the first gas is obtained by heating compressed air;

[0048] obtaining a second gas, wherein the second gas is obtained by heating the first gas;

[0049] Obtaining a third gas, wherein the third gas is obtained by heating the first gas; the temperature of the third gas is adapted to the target temperature of the furnace gas; and the temperature of the second gas is greater than the temperature of the third gas;

[0050] In the flow path before the gas in the furnace gas is condensed or liquefied, a third gas is used to insulate the pipes and filter 200 on the flow path, and the mixed mixture is made to flow in the flow path at a target temperature by controlling the mixing ratio of the first gas, the second gas and the furnace gas.

[0051] When the outlet gas is the gas produced by a direct current furnace treating high-arsenic-tin smoke, such as the gas produced by a direct current furnace, a rotary kiln, or a converter treating arsenic-tin smoke, quartz sand, and coke powder, the outlet gas contains dust and gaseous As2O3, and the temperature of the gas is 200-660°C. In order to keep the As2O3 in the outlet gas in a gaseous state, the temperature of the third gas is preferably 350-450°C, preferably 350-400°C, the temperature of the first gas is 320-370°C, preferably 320-350°C, and the temperature of the second gas is 400-450°C, preferably 400-420°C. A preferred embodiment is: the temperature of the third gas is 350°C, the temperature of the first gas is 320°C, and the temperature of the second gas is 420°C. In this case, the system stability is the best.

[0052] The filter element of the filter 200 needs to be back-blown and cleaned after being used for a certain period of time. In order to prevent disturbance to the system temperature, it is preferred to use the first gas to back-blown and clean the filter element.

[0053] It is preferred to use a PLC control system to control the mixing ratio of the first gas, the second gas and the furnace gas so that the mixed mixture flows on the flow path at the target temperature. This can improve control accuracy and reduce delays and errors caused by human control.

[0054] Figure 1 It is a structural schematic diagram of an embodiment of the processing equipment for furnace gas of the present invention.

[0055] like Figure 1 As shown, the processing equipment includes a filter 200 and an air inlet pipe and an air outlet pipe connected to the filter 200, the air inlet pipe is connected to the air outlet of a DC furnace, a rotary kiln or a converter, and the filter element in the filter 200 is a metal porous film; and the processing equipment also includes a temperature regulating component, which is used to regulate the temperature of the furnace gas from the furnace outlet temperature to a target temperature, which is higher than the desublimation temperature or the liquefaction temperature and lower than the tolerance temperature limit of the filter element in the filter 200.

[0056] The temperature control assembly includes a primary heating mechanism, a secondary heating mechanism, a tertiary heating mechanism, a temperature detection mechanism, and a PLC control system. The primary heating mechanism is used to heat compressed air into a first gas and pass the first gas into the air inlet pipe. The primary heating mechanism includes a primary heater 110, a first pipe, and a first valve. The first pipe connects the primary heater 110 and the air inlet pipe, and the first valve is located on the first pipe. The secondary heating mechanism is used to heat the first gas into a second gas and pass the second gas into the air inlet pipe. The secondary heating mechanism includes a secondary heater 120, a second pipe, and a second valve. The second pipe connects the secondary heater 120 and the air inlet pipe, and the second valve is located on the second pipe. The tertiary heating mechanism is used to heat the first gas into a third gas, and the third gas is used to insulate the filter 200, the air inlet pipe, and the air outlet pipe. The tertiary heating mechanism includes a jacket and a first fan 131. The jacket is located outside the filter 200, the air inlet pipe, and the air outlet pipe. The first fan 131 draws the third gas into the jacket. The temperature detection mechanism is used to detect the temperature of the gas to be filtered in the inlet duct and / or the temperature of the first dust-free gas in the outlet duct, and the temperature detection mechanism includes a temperature sensor. The PLC control system controls the opening and closing of the first valve and the second valve based on the detection value of the temperature detection mechanism. The PLC control system preferably includes, but is not limited to, a controller using a PID algorithm.

[0057] The processing equipment also includes a back-blowing mechanism for back-blowing and cleaning the filter element. The back-blowing mechanism includes a back-blowing pipe connected to the first-level heating mechanism, thereby preventing the back-blowing gas temperature from being too low to cause As2O3 to condense and precipitate.

[0058] Preferably, the processing equipment includes two filters 200 connected in parallel, thereby adopting a one-in-use and one-in-standby design to avoid affecting the normal operation of the furnace body when the filter 200 is backflushed.

[0059] The filter medium of the filter 200 is a metal porous film, which has strong high temperature resistance and corrosion resistance, and good air permeability, and can control the dust content of the first dust-free gas to 10mg / Nm 3 the following.

[0060] When the furnace gas is generated by treating arsenic-tin smoke, quartz sand and coke powder in a direct current furnace, a rotary kiln or a converter, and contains dust and gaseous As2O3, and the temperature of the furnace gas is 200-660°C, an embodiment of the method for treating the furnace gas includes the following steps:

[0061] (1) Using the above-mentioned temperature adjustment method or treatment equipment to adjust the temperature of the furnace gas from the furnace outlet temperature to 350-450° C. and perform high-temperature filtration treatment on the obtained gas to be filtered to obtain first dust-free gas;

[0062] (2) The first dust-free gas is subjected to a desublimation treatment to condense the gaseous As2O3 in the first dust-free gas into solid As2O3, thereby obtaining a desublimation gas containing solid As2O3; the desublimation treatment adopts gas-to-gas contact heat exchange, the cold source is compressed air at room temperature, and the temperature of the obtained desublimation gas is 50-100°C; preferably, a portion of the solid As2O3 is collected during the desublimation treatment to reduce the load of the subsequent gas-solid separation treatment.

[0063] (3) performing gas-solid separation on the condensed sublimation gas to obtain As2O3 product and second dust-free gas;

[0064] (4) desulfurizing the second dust-free gas to obtain clean gas;

[0065] (5) Clean gas is discharged through chimney 620.

[0066] Before the desublimation treatment, the gas to be filtered consisting of the first gas, the second gas and the furnace gas and the first dust-free gas obtained by filtration flow at a target temperature (i.e., 350-450° C.) through a temperature adjustment method or treatment equipment.

[0067] Figure 2 It is a structural schematic diagram of an embodiment of a system for processing furnace gas according to the present invention.

[0068] like Figure 2As shown, an embodiment of a furnace gas treatment system is used to treat furnace gas containing dust and gaseous As₂O₃ at a temperature of 200-660°C. The system specifically includes the aforementioned furnace gas treatment equipment, a condensation unit, a recovery unit, a desulfurization unit, and an exhaust unit. In the treatment equipment, a mixture of the first gas, the second gas, and the furnace gas is filtered through a filter 200 to produce a first dust-free gas. This first dust-free gas is mixed with compressed air in the condensation unit, where the gaseous As₂O₃ is condensed into solid As₂O₃, producing a sublimated gas containing solid As₂O₃. The condensation unit includes a gravity dust collector 300, which combines condensation and dust collection functions. The recovery unit performs gas-solid separation on the sublimated gas to produce an As₂O₃ product and a second dust-free gas. The recovery unit includes a bag filter 400. The desulfurization unit includes a dynamic wave scrubber 500. The exhaust unit includes a second fan 610 and a chimney 620 . The second dust-free gas is processed by the desulfurization unit to obtain clean gas, which is discharged through the chimney 620 under the traction of the second fan 610 .

[0069] The above describes the relevant contents of the present invention. Based on this description, a person skilled in the art will be able to implement the present invention. Based on the above contents of the present invention, all other embodiments obtained by a person skilled in the art without making any creative efforts should fall within the scope of protection of the present invention.

Claims

1. A method for regulating the temperature of discharged furnace gas containing dust and condensable or liquefiable gas, characterized in that: The temperature adjustment method is used to adjust the temperature of the furnace gas from the furnace outlet temperature to a target temperature, wherein the target temperature is higher than the desublimation temperature or the liquefaction temperature and lower than the tolerance temperature limit of the filter element in the filter (200) for recovering the dust; The temperature regulation method comprises the following steps: Obtaining a first gas, where the first gas is obtained by heating compressed air; obtaining a second gas, wherein the second gas is obtained by heating the first gas; Obtaining a third gas, wherein the third gas is obtained by heating the first gas; the temperature of the third gas is adapted to the target temperature of the furnace gas; and the temperature of the second gas is greater than the temperature of the third gas; Before the gas in the furnace gas is subjected to desublimation or liquefaction treatment, a third gas is used to insulate the pipes and filters (200) on the flow path, and the mixed mixture is made to flow on the flow path at a target temperature by controlling the mixing ratio of the first gas, the second gas and the furnace gas.

2. A method for regulating the temperature of discharged furnace gas, wherein the discharged furnace gas contains dust and gaseous As2O3 and the discharged furnace gas has a discharge temperature of 200 to 660°C, characterized in that: The temperature adjustment method is used to adjust the temperature of the furnace gas from the furnace outlet temperature to a target temperature, wherein the target temperature is higher than the desublimation temperature of gaseous As2O3 and lower than the tolerance temperature limit of the filter element in the filter (200) for recovering the dust; The temperature regulation method comprises the following steps: Obtaining a first gas, where the first gas is obtained by heating compressed air; the temperature of the first gas is 320-370° C.; Obtaining a second gas, wherein the second gas is obtained by heating the first gas; the temperature of the second gas is 400-450° C.; Obtaining a third gas, wherein the third gas is obtained by heating the first gas; the temperature of the third gas is 350-450° C.; and the temperature of the third gas is adapted to the target temperature of the furnace gas; Before desublimation of gaseous As2O3 in the outgoing furnace gas, a third gas is used to insulate the pipes and filters (200) on the flow path, and then the mixed ratio of the first gas, the second gas and the outgoing furnace gas is controlled to make the mixed mixture flow on the flow path at a target temperature.

3. The method for regulating the temperature of the furnace gas according to claim 2, wherein: The target temperature and the temperature of the third gas are 350-400°C, the temperature of the first gas is 320-350°C, and the temperature of the second gas is 400-420°C.

4. The method for regulating the temperature of the furnace gas according to claim 2, wherein: The first gas is used to back-blow and clean the filter element.

5. The method for regulating the temperature of the furnace gas as claimed in claim 2, wherein: The furnace gas is the furnace gas generated by treating arsenic-tin smoke, quartz sand and coke powder in a direct current furnace, a rotary kiln or a converter.

6. The method for regulating the temperature of the furnace gas as claimed in claim 2, wherein: A PLC control system is used to control the mixing ratio of the first gas, the second gas and the furnace gas so that the mixed mixture flows on the flow path at a target temperature.

7. A method for treating furnace gas, wherein the furnace gas is generated by treating arsenic-tin smoke, quartz sand, and coke powder in a direct current furnace, a rotary kiln, or a converter, the furnace gas containing dust and gaseous As2O3, and the furnace temperature of the furnace gas is 200-660°C, characterized in that: The treatment method includes the following steps: The temperature of the furnace gas is adjusted from the furnace outlet temperature to 350-450° C. by the temperature adjustment method according to any one of claims 2-6, and the obtained gas to be filtered is filtered to obtain the first dust-free gas; performing a desublimation treatment on the first dust-free gas to condense gaseous As2O3 in the first dust-free gas into solid As2O3, thereby obtaining a desublimation gas containing solid As2O3; The condensed sublimation gas is subjected to gas-solid separation treatment to obtain As2O3 product and second dust-free gas.

8. The method for treating furnace gas according to claim 7, wherein: The desublimation treatment adopts gas-to-gas contact heat exchange, the cold source is compressed air at room temperature, and the temperature of the obtained desublimation gas is 50-100°C.

9. The method for treating furnace gas according to claim 7, wherein: Some solid As2O3 was collected during the desublimation process.

10. The method for treating furnace gas according to claim 7, wherein: The method also includes desulfurizing the second dust-free gas; the desulfurized gas is discharged through a chimney (620).

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