A single-element arsenic continuous preparation device based on thermal stress driving and a preparation method thereof

Abstract

The application discloses a kind of single-element arsenic continuous preparation device and preparation method based on thermal stress driving, including the following devices arranged in sequence: for heating crude arsenic trioxide, to produce arsenic trioxide vapor evaporator;Reducing agent is introduced into arsenic trioxide vapor, and it is reduced to single-element arsenic vapor by reducing agent;Single-element arsenic vapor is introduced into crystallizer, single-element arsenic is prepared, and arsenic tail gas is discharged;Arsenic tail gas is introduced into quenching cyclone, arsenic powder is generated, and arsenic powder is introduced into evaporator while discharging second-stage tail gas;Dust remover is used for dust removal and discharge of second-stage tail gas;The application has the beneficial effect that: a new crystallization separation mechanism is created: the application breaks through the traditional thinking that temperature control is only used for "condensation" or "heat preservation", and creatively cooperates "conical tube structure", "near-vertical arrangement" and "wide temperature range (-20 DEG C to 420 DEG C) programmed cold and hot alternation".

Description

Technical Field

[0001] This invention relates to the field of pyrometallurgy and high-purity material preparation technology, specifically to an apparatus and method for the continuous and automated preparation of elemental arsenic from arsenic-containing materials, and particularly to an apparatus and method for the continuous preparation of elemental arsenic based on thermal stress-driven processes. Background Technology

[0002] Elemental arsenic is an important industrial raw material. The current mainstream process adopts a segmented production method: first, high-arsenic materials (such as crude arsenic trioxide) are volatilized, condensed and purified into solid arsenic trioxide; then, the solid arsenic trioxide is mixed with a reducing agent and heated in a reduction furnace to generate arsenic vapor, which is finally condensed and collected in a crystallizer (mostly vertical tank type).

[0003] This process has many inherent defects, mainly concentrated in the crystallization and collection stage. For example, the equipment disclosed in Chinese patent document (publication number CN213060988U) uses arsenic trioxide as raw material, which is fine arsenic trioxide purified in a purification furnace (as can be seen from the fact that the volatilization furnace is not equipped with a residue discharge device). Elemental arsenic condenses on the inner wall of the condenser tube, requiring the machine to be stopped and cooled to below 50°C before the top cover is lifted out by a crane, and workers must open the equipment and knock it off. The shortcomings of this method include: Discontinuous production: requires intermittent operation, resulting in low efficiency.

[0004] Major safety hazard: When opening the lid and tapping to separate crystals, arsenic dust can easily spill out, endangering the health of operators.

[0005] Decreasing product yield: Although an electronic vibrator is installed, it cannot completely prevent the condensation efficiency from decreasing as the crystal layer thickens on the inner wall of the condenser tube. Furthermore, breaking the crystals by tapping after disassembling the equipment can easily cause product breakage and loss.

[0006] The process is lengthy and energy-intensive: the two processes are completely independent, and the intermediate materials need to undergo cooling, transfer and reheating, resulting in serious energy waste.

[0007] Although the industry has been working to solve the technical pain points of "segmented purification, repeated furnace shutdowns, opening the lid for hoisting and dismantling, and knocking unloading", existing improvements are mostly focused on optimizing the knocking tools or strengthening the seal, and have failed to fundamentally achieve continuous, automatic and safe separation. Summary of the Invention

[0008] The purpose of this invention is to provide a continuous preparation device and method for elemental arsenic based on thermal stress, which realizes the continuous preparation of elemental arsenic and the automatic, non-contact exfoliation of elemental arsenic crystals. Through innovative structural design and precise temperature program control, it utilizes the differences in the thermodynamic properties of materials to drive the crystalline layer to actively and completely peel off from the substrate, thereby achieving a safe, efficient, and continuous preparation process.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A continuous preparation apparatus for elemental arsenic based on thermal stress drive includes the following devices arranged in sequence: A volatilization furnace used to heat crude arsenic trioxide to produce arsenic trioxide vapor; A reduction furnace that introduces arsenic trioxide vapor and reduces it to elemental arsenic vapor using a reducing agent; A crystallizer for introducing elemental arsenic vapor, preparing elemental arsenic, and discharging arsenic tail gas; Arsenic tail gas is introduced to generate arsenic powder, and the arsenic powder is introduced into the volatilization furnace while the second stage tail gas is discharged by a quenching cyclone. A dust collector for removing dust from the exhaust gas of the second stage.

[0010] Preferably, the device further includes an unpacking device for opening the crude arsenic trioxide, the outlet of which is connected to the first inlet of the feed hopper via a sealed first conveyor belt, and the outlet of the feed hopper is connected to the volatilization furnace.

[0011] Preferably, a first heating element is provided on the side wall of the volatilization furnace, and a second conveyor belt for conveying crude arsenic trioxide is provided inside the volatilization furnace, with a tailings box for collecting the residue of the crude arsenic trioxide at the end of the second conveyor belt.

[0012] Preferably, a second heating element is provided on the side wall of the reduction furnace, a reducing agent chamber for containing reducing agent is provided at the upper part of the reduction furnace, and a reduction residue box is provided at the lower part of the reduction furnace.

[0013] Preferably, the crystallizer is divided into three chambers from top to bottom by two partitions, namely an upper tube box, a crystallization box, and a lower tube box. The crystallization box contains multiple parallel conical crystallization tubes. The lower ends of the crystallization tubes all pass through the lower partition and communicate with the lower tube box, and the upper ends of the multiple crystallization tubes all pass through the upper partition and communicate with the upper tube box. A vibrator is installed on the side wall of the crystallization box. The side wall of the crystallization box has a temperature-controlled medium inlet and a temperature-controlled medium outlet. A sealed space for containing the temperature-controlled medium is formed between the crystallization box and the multiple crystallization tubes. Independent hot medium pipelines and cold medium pipelines are provided between the temperature-controlled medium inlet and the temperature-controlled medium outlet. The upper tube box has an arsenic tail gas outlet connected to the quenching cyclone separator on its side wall, and an arsenic vapor inlet connected to the reduction furnace on its side wall. A crusher is installed at the bottom of the lower tube box.

[0014] Preferably, one or more crystallizers are provided, and multiple crystallizers are arranged in parallel and are all connected to the quenching cyclone and the reduction furnace.

[0015] Preferably, an arsenic tail gas pipeline for conveying arsenic tail gas is provided between the upper pipe box and the quenching cyclone, and the arsenic tail gas pipeline is connected to a cooling nitrogen source through a nitrogen valve.

[0016] Preferably, the bottom of the quenching cyclone has an arsenic powder outlet, which is connected to the second inlet of the feed hopper.

[0017] Preferably, the volatilization furnace is also connected to an auxiliary heating device, the outlet of the dust collector is connected to the inlet of the auxiliary heating device, and the outlet of the auxiliary heating device is connected to an exhaust stack via a fan.

[0018] Preferably, this application also discloses a continuous preparation method for elemental arsenic based on thermal stress, which, based on the aforementioned continuous preparation apparatus, includes the following steps: S1. The unpacking device unpacks the crude arsenic trioxide, and the unpacked crude arsenic trioxide enters the feed hopper along the first conveyor belt; S2. The crude arsenic trioxide in the feed hopper enters the volatilization furnace. The first heating element heats the volatilization furnace, causing the crude arsenic trioxide to generate arsenic trioxide vapor. The remaining crude arsenic trioxide is sent to the tailings box by the second conveyor belt. S3. Arsenic trioxide vapor enters the reduction furnace. The second heating element heats the reduction furnace. The reducing agent is added to the reducing agent chamber to convert the arsenic trioxide vapor into elemental arsenic vapor. The residue generated in this process enters the reduction residue box. S4. Elemental arsenic vapor enters the crystallizer and flows upward along the crystallization tubes. During this process, a temperature-controlled medium of 280℃~420℃ is introduced into the crystallization box to cause the elemental arsenic vapor to sublimate and crystallize, forming a crystal layer. S5. After the crystallized layer reaches a certain thickness, stop the input of elemental arsenic vapor, and at the same time, introduce a cold medium of -20℃~50℃ into the crystallization box and maintain it for 5~30 minutes to allow the crystallized layer to fall off from the crystallization tube. Start the vibrator to promote the falling off of the crystallized layer. The fallen crystallized layer is crushed by the crusher and collected. S6. Based on the number of crystallizers set, they are divided into two groups. While one group of crystallizers is performing step S4, the other group of crystallizers is performing step S5. Elemental arsenic vapor alternately enters the two groups of crystallizers to achieve continuous preparation of elemental arsenic. S7. During the process of arsenic tail gas entering the quench separator, the nitrogen valve is opened and cold nitrogen gas at -20℃~40℃ is introduced, causing the arsenic tail gas to condense into arsenic powder. The arsenic powder enters the feed hopper from the bottom of the quench separator and then enters the volatilization furnace again to achieve in-situ circulation. At the same time, the quench separator discharges the second stage tail gas. S8. After the second stage exhaust gas is cleaned by the dust collector, it enters the auxiliary heating device for combustion, and then passes through the fan and exhaust stack in sequence to meet the emission standards.

[0019] The beneficial effects of this invention are as follows: 1. A novel crystallization separation mechanism has been created: This application breaks through the traditional thinking that temperature control is only used for "condensation" or "heat preservation," creatively combining "conical tube structure," "near-vertical arrangement," and "programmed alternation of hot and cold temperatures over a wide temperature range (-20℃ to 420℃)." The core of this mechanism is to create a large temperature difference (e.g., 400℃ to -20℃) that induces intense, asynchronous cooling and contraction between the metal tube wall and the arsenic crystal layer, thereby generating strong shear stress at the interface. This stress, as an active, non-contact driving force, is sufficient to overcome the adhesion of crystals and achieve the automatic peeling of the α-state arsenic block.

[0020] 2. Revolutionary safety and continuous production achieved: The above separation mechanism completely eliminates the high-risk manual opening and tapping operation, fundamentally solving the safety hazard of arsenic dust leakage. Simultaneously, the separation process is rapid and controllable, enabling the crystallization, separation, and collection processes to be repeated, laying a core foundation for achieving continuous production throughout the entire process and significantly improving production efficiency.

[0021] 3. Ensures high and stable product yield: Automatic stripping avoids product breakage losses caused by manual operation. More importantly, regular and thorough stripping ensures a constant condensation surface area, thus solving the industry problem of continuously declining condensation efficiency and direct yield caused by the thickening of the crystal layer in traditional processes, and keeping the product yield at a high level for a long time.

[0022] 4. A highly efficient short process and material closed loop have been formed: By directly connecting the volatilization unit and the reduction unit in the gas phase, the cooling, transfer, and reheating processes of intermediate products are eliminated, significantly reducing energy consumption and forming a highly efficient short process. By directly returning the arsenic powder recovered from the tail gas treatment unit to the raw material system, a closed-loop circulation of arsenic element within the system is realized, further improving the overall recovery rate and reducing material loss and environmental pollution.

[0023] 5. The carbon monoxide in the flue gas after exhaust gas treatment is burned to supplement the heat of the volatilization furnace, realizing full recovery and utilization of system energy and reducing power consumption.

[0024] 6. In addition, this application can directly use crude arsenic trioxide as a production raw material, which solves the problem that prior purification is required in the prior art, further optimizes the production process and reduces production costs. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the preparation apparatus in this application.

[0026] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0027] The present invention will now be further described with reference to the accompanying drawings. Example

[0028] like Figure 1 As shown, a continuous preparation apparatus for elemental arsenic based on thermal stress includes the following devices arranged in sequence: Unpacking device 1: The packaging bag containing crude arsenic trioxide is placed into the unpacking device 1. After unpacking, it is transported to the feeding hopper 3 by the first conveyor belt 2. In this embodiment, the first conveyor belt 2 is a tubular chain conveyor, which is sealed to reduce the leakage of crude arsenic trioxide. Volatilizer 4: The outlet of the feed hopper 3 is connected to the volatilizer 4. A first heating element 6 is provided on the side wall of the volatilizer. In this embodiment, the first heating element 6 is an electric heating wire or an electric heating rod, used to heat the crude arsenic trioxide and volatilize it at about 750°C to generate arsenic trioxide vapor. A second conveyor belt 5 is also provided inside the volatilizer 4. In this embodiment, the second conveyor belt 5 is a steel belt, which can send the residue of the crude arsenic trioxide into the tailings box 7 (because the arsenic trioxide used is crude, a certain amount of residue will be generated. If the crude arsenic trioxide used is purified fine material, less residue or even no residue will be generated).

[0029] Reduction furnace 8: A second heating element 9 is provided on the side wall of the reduction furnace 8. A reducing agent chamber 10 for containing the reducing agent is provided at the upper part of the reduction furnace 8. A reduction residue box 11 is provided at the lower part of the reduction furnace. In this embodiment, the reducing agent used is a carbonaceous reducing agent. The second heating element 9 is an electric heating wire or an electric heating rod. After the arsenic trioxide vapor generated in the volatilization furnace 4 enters the reduction furnace 8, it reacts with the reducing agent at about 800°C to generate elemental arsenic vapor. The residue generated in this process enters the reduction residue box 11 under its own gravity. Crystallizer: The crystallizer is divided into three chambers from top to bottom by two partitions: an upper tube box, a crystallization chamber 12, and a lower tube box. The crystallization chamber 12 contains multiple parallel conical crystallization tubes 14, arranged vertically with a smaller diameter at the top and a larger diameter at the bottom. The lower ends of the crystallization tubes 14 pass through the lower partition and connect to the lower tube box, while the upper ends pass through the upper partition and connect to the upper tube box. A vibrator 19 is installed on the side wall of the crystallization chamber 12. A temperature-controlled medium inlet 17 and a temperature-controlled medium outlet 18 are provided on the side wall of the crystallization chamber 12. A sealed space for containing the temperature-controlled medium is formed between the crystallization chamber 12 and the multiple crystallization tubes 14. Independent hot and cold medium pipelines are provided between the temperature-controlled medium inlet 17 and the temperature-controlled medium outlet 18. A hot medium tank 15 (using electric heating for heating and a heat exchanger for cooling to achieve precise temperature control) is installed on the hot medium pipeline. A cold medium tank 16 (using cascade refrigeration or a cooling tower for cooling) is installed on the cold medium pipeline. Valves controlling the on / off state of the pipelines are also installed on both pipelines. In this embodiment, the medium used is oil. When hot oil needs to be injected, the cold medium pipeline is closed by the valve to prevent hot oil from entering the cold oil tank. At this time, the hot oil pump connected to the hot medium tank 15 is started, allowing the hot oil to circulate within the crystallization tank 12. When cold oil needs to be injected, the hot medium pipeline is closed by the valve to prevent cold oil from entering the hot oil tank. At this time, the cold oil pump connected to the cold medium tank 16 is started, allowing the cold oil to circulate within the crystallization tank 12. The aforementioned separate hot oil / cold oil inlet control method is existing conventional technology and will not be described in detail in this embodiment.

[0030] An arsenic tail gas outlet 20 connected to a quenching cyclone is provided on the side wall of the upper tube box, and an arsenic steam inlet 13 connected to a reduction furnace 8 is provided on the side wall of the lower tube box. A crusher 21 is also provided at the bottom of the lower tube box for crushing arsenic crystal blocks and introducing them into the product bin 22.

[0031] In this embodiment, two crystallizers are provided and connected in parallel. Both crystallizers are connected to the quenching cyclone 23 and the reduction furnace 8. When the elemental arsenic vapor from the reduction furnace 8 enters one of the crystallizers, a hot medium is introduced into the crystallizer, and elemental arsenic crystals are generated. During this process, the valve prevents the introduction of elemental arsenic vapor into the other crystallizer. At this time, a cold medium is introduced into the other crystallizer, and elemental arsenic crystals are extracted. The operation of the two crystallizers alternates to achieve continuous production of elemental arsenic crystals. During this process, the connection or disconnection between the two crystallizers and the reduction furnace 8 and the quenching cyclone 23 needs to be controlled by the valve. This control is a conventional technology and will not be described in detail in this embodiment. In some embodiments, the number of crystallizers can be increased or decreased accordingly based on the raw material processing speed of the unpacking device 1, the volatilization furnace 4 and the reduction furnace 8, the exhaust gas processing speed of the quenching cyclone 23 and the dust collector 25, and the elemental arsenic generation and extraction speed of the hot medium box 15, the hot oil pump, the cold medium box 16 and the cold oil pump. This embodiment will not be described in detail, and this scheme should also be included within the protection scope of this application.

[0032] Rapid Cooling Cyclone 23: Arsenic tail gas discharged from the upper pipe box enters the rapid cooling cyclone 23 along the arsenic tail gas pipeline. The arsenic tail gas pipeline is connected to the cooling nitrogen source through the nitrogen valve 24. After the arsenic tail gas at about 300°C comes into contact with and mixes with the cooling nitrogen at -20°C to 40°C, the temperature will drop to about 100°C within a few seconds, causing the arsenic tail gas to condense into ultrafine arsenic powder instantly and be captured by the rapid cooling cyclone 23. During this process, purified secondary tail gas is generated. An arsenic powder outlet is opened at the bottom of the rapid cooling cyclone 23, which is connected to the feed hopper 3. The arsenic powder re-enters the volatilization furnace 4 along the feed hopper 3 to achieve in-situ circulation. In this embodiment, the feed hopper 3 has two feed ports, which are respectively connected to the first conveyor belt 2 and the arsenic powder outlet.

[0033] Dust collector 25: The second-stage exhaust gas discharged from the quenching cyclone separator 23 enters the dust collector 25 for dust removal. Because the second-stage exhaust gas contains a large amount of carbon monoxide, in this embodiment, an auxiliary heating device (not shown in the figure) is also connected to the outside of the volatilization furnace 4. The dust-removed second-stage exhaust gas enters the auxiliary heating device for combustion and heat release, which plays an auxiliary heating role for the volatilization furnace 4, reducing the energy consumption of the first heating element 6. The exhaust gas after combustion is discharged along the fan 26 and the exhaust stack 27. In order to promote the combustion of the second-stage exhaust gas, the auxiliary heating device can also be connected to combustion air. A secondary dust removal device can also be set between the auxiliary heating device and the fan 26. These are all existing conventional technologies, which will not be described in detail in this embodiment.

[0034] Based on the aforementioned continuous preparation apparatus, this embodiment also discloses a continuous preparation method for elemental arsenic driven by thermal stress, comprising the following steps: S1. The unpacking device 1 unpacks the crude arsenic trioxide, and the unpacked crude arsenic trioxide enters the feed hopper 3 along the first conveyor belt 2. S2. The crude arsenic trioxide in the feed hopper 3 enters the volatilization furnace 4. The first heating element 6 heats the volatilization furnace to about 750°C, and the crude arsenic trioxide volatilizes to generate arsenic trioxide vapor. The remaining crude arsenic trioxide is sent to the tailings box 7 by the second conveyor belt 5. S3. Arsenic trioxide vapor enters the reduction furnace 8. The second heating element 9 heats the reduction furnace 8 to about 800°C. During this process, the reducing agent chamber 10 adds reducing agent to the reduction furnace 8. The reducing agent reacts with the arsenic trioxide vapor to generate elemental arsenic vapor. The residue generated during this process enters the reduction residue box 11. S4. The elemental arsenic vapor generated in step S3 enters the crystallizer and flows upward along the crystallization tube 14. During this process, the heat medium pipeline is started to introduce a heat medium at 280°C to 420°C into the crystallization box, so that the elemental arsenic vapor sublimates and crystallizes to form a crystal layer. S5. After the crystallized layer reaches a certain thickness (which is calculated by the amount of arsenic trioxide raw material added), the input of elemental arsenic vapor is stopped, and at the same time, a cold medium of -20℃ to 50℃ is introduced into the crystallization box. Within 5 to 30 minutes, the temperature of the medium in the crystallization box 12 is reduced from 280℃ to 420℃ to -20℃ to 50℃ and maintained for 5 to 30 minutes, so that the crystallized layer detaches from the inner wall of the crystallization tube 14 and slides down. During this process, the vibrator 19 can be started to promote the detachment of the crystallized layer. The detached crystallized layer is crushed by the crusher 21 and then enters the product bin 22 for collection. In step S5 above, the preferred temperature range for the cooling medium is -20°C to -50°C. This embodiment achieves a wide-temperature-range programmed alternation of hot and cold media, particularly reducing the temperature of the shell-side medium (i.e., the space between the crystallizer 12 and the crystallizer tubes 14) to below 0°C, preferably a deep cooling capacity of 0°C to -20°C. This is a key and necessary technical condition for achieving reliable thermal stress separation. Its lower temperature limit far exceeds the temperature control range of conventional crystallizers in the field (typically >50°C).

[0035] S6. Based on the raw material processing speed, tail gas processing speed, and the generation and extraction speed of elemental arsenic in each crystallizer, the number of crystallizers can be set independently. Multiple crystallizers are arranged in parallel and divided into at least two groups. When one group of crystallizers is performing step S4, the other group of crystallizers is performing step S5. Elemental arsenic vapor alternately enters the two groups of crystallizers to achieve continuous preparation of elemental arsenic. Of course, multiple crystallizers can also be divided into three or more groups, and multiple groups of crystallizers can sequentially and alternately perform steps S4 and S5 to achieve continuous preparation of elemental arsenic. This will not be described in detail here. S7. When the arsenic tail gas discharged from the crystallizer (temperature around 250℃~350℃) enters the quench separator 23, the nitrogen valve is opened and cooling nitrogen at -20℃~40℃ is introduced, so that the temperature of the arsenic tail gas drops below 100℃ within 10 seconds and condenses into arsenic powder. The arsenic powder enters the feed hopper 3 from the bottom of the quench separator 23, and then enters the volatilization furnace 4 again to achieve in-situ circulation. At the same time, the quench separator 23 discharges the second stage tail gas. S8. After the second stage exhaust gas is cleaned by the dust collector 25, it enters the auxiliary heating device for combustion, and then passes through the fan 26 and the exhaust pipe 27 in sequence to meet the emission standards.

[0036] The above embodiments are not intended to limit the shape, material, structure, etc. of the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0038] If the terms "first" or "second" are used in this document to define components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing the invention and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous preparation apparatus for elemental arsenic based on thermal stress, characterized in that, Includes the following devices arranged in sequence: A volatilization furnace used to heat crude arsenic trioxide to produce arsenic trioxide vapor; A reduction furnace that introduces arsenic trioxide vapor and reduces it to elemental arsenic vapor using a reducing agent; A crystallizer for introducing elemental arsenic vapor, preparing elemental arsenic, and discharging arsenic tail gas; Arsenic tail gas is introduced to generate arsenic powder, and the arsenic powder is introduced into the volatilization furnace while the second stage tail gas is discharged by a quenching cyclone. A dust collector for removing dust from the exhaust gas of the second stage.

2. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 1, characterized in that, It also includes a depacking device for opening crude arsenic trioxide, the outlet of which is connected to the first inlet of a feed hopper via a sealed first conveyor belt, the outlet of which is connected to a volatilization furnace.

3. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 2, characterized in that, A first heating element is provided on the side wall of the volatilization furnace, and a second conveyor belt for conveying crude arsenic trioxide is provided inside the volatilization furnace. A tailings box for collecting the residue of crude arsenic trioxide is provided at the end of the second conveyor belt.

4. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 3, characterized in that, The reduction furnace has a second heating element on its side wall, a reducing agent chamber for containing reducing agent in its upper part, and a reduction residue box in its lower part.

5. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 4, characterized in that, The crystallizer is divided into three chambers from top to bottom by two partitions: an upper tube box, a crystallization chamber, and a lower tube box. The crystallization chamber contains multiple parallel conical crystallization tubes. The lower ends of each crystallization tube pass through the lower partition and connect to the lower tube box, while the upper ends of each crystallization tube pass through the upper partition and connect to the upper tube box. A vibrator is installed on the side wall of the crystallization chamber. A temperature-controlled medium inlet and outlet are provided on the side wall of the crystallization chamber. A sealed space for containing the temperature-controlled medium is formed between the crystallization chamber and the multiple crystallization tubes. Independent hot and cold medium pipelines are provided between the temperature-controlled medium inlet and outlet. The upper tube box has an arsenic tail gas outlet connected to the quenching cyclone separator on its side wall, and an arsenic vapor inlet connected to the reduction furnace on its side wall. A crusher is installed at the bottom of the lower tube box.

6. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 5, characterized in that, The crystallizer is provided in one or more ways, and multiple crystallizers are arranged in parallel and are all connected to the quenching cyclone and the reduction furnace.

7. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 6, characterized in that, An arsenic tail gas pipeline for conveying arsenic tail gas is provided between the upper pipe box and the quenching cyclone. The arsenic tail gas pipeline is connected to a cooling nitrogen source through a nitrogen valve.

8. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 7, characterized in that, The bottom of the quenching cyclone has an arsenic powder outlet, which is connected to the second inlet of the feed hopper.

9. The continuous preparation apparatus for elemental arsenic based on thermal stress drive according to claim 8, characterized in that, The volatilization furnace is also connected to an auxiliary heating device. The outlet of the dust collector is connected to the inlet of the auxiliary heating device, and the outlet of the auxiliary heating device is connected to the exhaust stack via a fan.

10. A continuous preparation method for elemental arsenic based on thermal stress, using the continuous preparation apparatus described in claim 9, characterized in that, Includes the following steps: S1. The unpacking device unpacks the crude arsenic trioxide, and the unpacked crude arsenic trioxide enters the feed hopper along the first conveyor belt; S2. The crude arsenic trioxide in the feed hopper enters the volatilization furnace. The first heating element heats the volatilization furnace, causing the crude arsenic trioxide to generate arsenic trioxide vapor. The remaining crude arsenic trioxide is sent to the tailings box by the second conveyor belt. S3. Arsenic trioxide vapor enters the reduction furnace. The second heating element heats the reduction furnace. The reducing agent is added to the reducing agent chamber to convert the arsenic trioxide vapor into elemental arsenic vapor. The reducing agent residue generated in this process enters the reduction residue box. S4. Elemental arsenic vapor enters the crystallizer and flows upward along the crystallization tubes. During this process, a temperature-controlled medium of 280℃~420℃ is introduced into the crystallization box to cause the elemental arsenic vapor to sublimate and crystallize, forming a crystal layer. S5. After the crystallized layer reaches a certain thickness, stop the input of elemental arsenic vapor, and at the same time, introduce a cold medium of -20℃~50℃ into the crystallization box and maintain it for 5~30 minutes to allow the crystallized layer to fall off from the crystallization tube. Start the vibrator to promote the falling off of the crystallized layer. The fallen crystallized layer is crushed by the crusher and collected. S6. Based on the number of crystallizers set, they are divided into two groups. While one group of crystallizers is performing step S4, the other group of crystallizers is performing step S5. Elemental arsenic vapor alternately enters the two groups of crystallizers to achieve continuous preparation of elemental arsenic. S7. During the process of arsenic tail gas entering the quench separator, the nitrogen valve is opened and nitrogen gas at -20℃~40℃ is introduced, so that the arsenic vapor in the arsenic tail gas condenses into arsenic powder. The arsenic powder enters the feed hopper from the bottom of the quench separator and then enters the volatilization furnace again to achieve in-situ circulation. At the same time, the quench separator discharges the second stage tail gas. S8. After the second stage exhaust gas is cleaned by the dust collector, it enters the auxiliary heating device for combustion, and then passes through the fan and exhaust stack in sequence to meet the emission standards.

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