Phosphorus recovery processing system and recovery processing method thereof

Abstract

The invention provides a phosphorus recovery processing system and a recovery processing method thereof. During recovery processing, cooling equipment is communicated with a growth chamber of molecular beam epitaxy equipment, so that the pressure of the cooling equipment is lower than atmospheric pressure, and a phosphorus material in the growth chamber is driven into the cooling equipment through baking; isolating the growth chamber from the cooling equipment, introducing heated nitrogen into the cooling equipment, purging phosphorus-containing gas in the cooling equipment, and discharging the phosphorus-containing gas outwards; phosphorus-containing gas is conveyed to a first treatment main body of the treatment equipment and is subjected to cooling, hydrogen peroxide treatment, copper sulfate treatment, potassium permanganate treatment and inspection treatment in sequence, and finally waste liquid is discharged to a first neutralizing tank for alkaline neutralization treatment. Through the configuration, the safety and the treatment efficiency of phosphorus recovery treatment are remarkably improved.

Description

Technical Field

[0001] This application belongs to the field of semiconductor manufacturing technology, specifically relating to a phosphorus recovery system and method for molecular beam epitaxy. Background Technology

[0002] Molecular beam epitaxy (MBE) is a physical deposition technique for multilayer thin films of compound semiconductors. Its basic principle is to add the constituent elements of the thin film into their respective molecular beam furnaces under ultra-high vacuum conditions, forming a directional molecular beam that is then projected onto a heated substrate to grow the film. Phosphorus is a commonly used doping element in MBE, and phosphide growth via MBE is widely applied in semiconductor manufacturing.

[0003] Currently, high-purity red phosphorus needs to be installed in a pyrolysis furnace. This can be either crushed material or ingots of the corresponding size. The red phosphorus is then converted into white phosphorus within the furnace. Phosphorus, especially white phosphorus, is extremely difficult to maintain in the molecular beam epitaxy (MEB) chamber after phosphide growth due to its loose texture and extremely low ignition point, leading to frequent safety accidents. The fumes from burning phosphorus materials also cause physiological toxicity to personnel using and maintaining MEB on-site, requiring strict safety precautions. Therefore, a phosphorus recovery system is currently used. Before opening the chamber for maintenance after MEB growth, high-temperature baking is performed to drive excess phosphorus material into a cold trap cooled by liquid nitrogen. After baking, the cold trap is isolated from the MEB chamber, and the phosphorus-containing gas is then discharged to a phosphorus recovery unit containing liquid nitrogen for recycling.

[0004] The existing solution has the following problems: White phosphorus vapor evaporates and enters the cold trap containing liquid nitrogen after being heated in the cold trap. The liquid nitrogen needs to be introduced twice, once in the cold trap and once in the phosphorus recovery unit, and the waiting time for reheating is too long, which increases time and equipment costs and has an adverse impact on production efficiency and cost control. The phosphorus recovery unit is essentially a simple cold trap, and operators cannot visually judge the processing status of phosphorus recovery, which increases the uncertainty of phosphorus recovery. It also lacks vacuum insulation, which can easily cause problems such as pipe icing and blockage, liquid nitrogen leakage, or frostbite to operators. Secondly, the white phosphorus discharge stage of the cold trap takes a long time (e.g., 2-3 days), and both the cold trap and the phosphorus recovery unit are equipped with multi-stage pump sets and chambers, which further increases equipment and operating costs. Furthermore, when the phosphorus recovery unit is processed alone, it is inevitable to open the chamber, which cannot prevent a large amount of phosphorus material from coming into contact with air and causing deflagration, resulting in safety accidents. Summary of the Invention

[0005] To address the shortcomings of existing technologies, based on one aspect of this application, a phosphorus recovery and processing system is provided, comprising: a cooling device, which is scalably connected to the growth chamber of a molecular beam epitaxy apparatus, wherein the cooling device is configured to input heated nitrogen gas after the growth chamber has been baked, so as to use the heated nitrogen gas to purge phosphorus-containing gases inside the cooling device and discharge them to the outside; and a processing device, including a main processing unit, which is detachably connected to the cooling device;

[0006] The main processing device includes a first water-cooling structure and a transparent first processing body. The first processing body includes a first neutralization tank and a first processing chamber, a second processing chamber, a third processing chamber, a fourth processing chamber, and a first testing chamber connected in sequence. The first processing chamber is used to hold cooling water. The second processing chamber is used to hold hydrogen peroxide solution. The third processing chamber is used to hold copper sulfate solution. The fourth processing chamber is used to hold potassium permanganate solution. The first testing chamber is used to hold silver nitrate test paper and copper sulfate solution. The first processing chamber is used to receive phosphorus-containing gas discharged from the cooling device. The first neutralization tank is diaphragmably connected to the first processing chamber, the second processing chamber, the third processing chamber, the fourth processing chamber, and the first testing chamber. The first neutralization tank is used to hold an alkaline solution, which is a sodium hydroxide solution or a saturated lime milk solution. The first water-cooling structure is disposed outside the first processing body to cool the first processing body.

[0007] In some embodiments, a first gate valve or a third gate valve is provided between the growth chamber and the cooling device; the cooling device is respectively connected to a nitrogen delivery pipeline and an exhaust gas delivery pipeline; the nitrogen delivery pipeline is used to deliver heated nitrogen; the exhaust gas delivery pipeline is connected to the main processing unit and is used to deliver phosphorus-containing gas to the main processing unit; the nitrogen delivery pipeline and the exhaust gas delivery pipeline are provided with solenoid valves or manual valves, and the solenoid valves are communicatively connected to the controller.

[0008] In some embodiments, the cooling device is a cold trap, and a first gate valve is provided between the cold trap and the growth chamber; the cold trap is also connected to a molecular pump, and a second gate valve is provided between the cold trap and the molecular pump; the cold trap has a nitrogen purging port, an exhaust gas port, a liquid inlet port and a nitrogen purging port, the nitrogen purging port is connected to the nitrogen delivery pipeline, the exhaust gas port is connected to the exhaust gas delivery pipeline, the liquid inlet port is connected to the liquid nitrogen inlet pipe, and the nitrogen purging port is connected to the exhaust pipe.

[0009] In some embodiments, the cooling device is a cold pump, and the third gate valve is provided between the cold pump and the growth chamber. The cold pump is connected to the nitrogen delivery pipeline and the waste gas delivery pipeline through a three-way valve.

[0010] In some embodiments, the cold trap is provided with at least one of a heating plate, a second thermocouple, and a vacuum gauge. The heating plate is configured to heat the cold trap after the growth chamber has been baked. The second thermocouple is used to measure the temperature inside the cold trap, and the vacuum gauge is used to measure the vacuum level inside the cold trap.

[0011] In some embodiments, the first processing body is provided with a first thermocouple for measuring the temperature inside the first processing cavity, and / or, a turbidity sensor is provided in the first neutralization tank.

[0012] In some embodiments, a conduit is provided in the first processing cavity, the second processing cavity, the third processing cavity, the fourth processing cavity, and the first inspection cavity, and a porous distributor is provided at the bottom of the conduit; and / or, a baffle is provided in the first processing cavity, the second processing cavity, the third processing cavity, and the fourth processing cavity.

[0013] In some embodiments, the processing apparatus further includes a backup processing device, which is detachably connected to the main processing device; the backup processing device includes a second water-cooling structure and a transparent second processing body; the second processing body includes a second neutralization tank and a backup first processing chamber, a backup second processing chamber, and a second testing chamber connected in sequence; the backup first processing chamber is used to hold a copper sulfate solution; the backup second processing chamber is used to hold a potassium permanganate solution; the second testing chamber is used to hold silver nitrate test paper and a copper sulfate solution; the backup first processing chamber is used to receive phosphorus-containing gas discharged from the first testing chamber; the second neutralization tank is diaphragmably connected to the backup first processing chamber, the backup second processing chamber, and the second testing chamber, and is used to hold an alkaline solution; the second water-cooling structure is disposed outside the second processing body to cool the second processing body.

[0014] In some embodiments, a spare conduit is provided in each of the spare first processing chamber, the spare second processing chamber, and the second testing chamber, and a porous distributor is provided at the bottom of the spare conduit; and / or a spare baffle is provided in each of the spare first processing chamber and the spare second processing chamber; and / or a turbidity sensor is provided in the second neutralization tank.

[0015] In some embodiments, both the first processing body and the second processing body are made of acrylic sheet or quartz glass, the surface of which is covered with a polytetrafluoroethylene coating.

[0016] Based on another aspect of this application, a recovery process method performed by a phosphorus recovery system is provided, comprising the following steps:

[0017] S1. Connect the growth chamber and the cooling device, start the cooling device to make the pressure inside the cooling device lower than atmospheric pressure, and drive the phosphorus material in the growth chamber into the cooling device by baking.

[0018] S2. Isolate the growth chamber and the cooling equipment, and introduce heated nitrogen into the cooling equipment to purge the phosphorus-containing gas inside the cooling equipment and discharge it to the outside.

[0019] S3. The phosphorus-containing gas discharged from the cooling equipment is transported to the first processing body and sequentially undergoes cooling treatment, hydrogen peroxide treatment, copper sulfate treatment, potassium permanganate treatment and inspection treatment. The treated waste liquid is then discharged to the first neutralization tank for alkaline neutralization treatment.

[0020] In some embodiments, step S1 further includes: opening a first gate valve or a third gate valve to connect the growth chamber and the cooling device, monitoring the content of white phosphorus in the growth chamber using a residual gas analyzer, and closing the first gate valve or the third gate valve in response to the content of white phosphorus in the growth chamber reaching a safe value, wherein the first gate valve or the third gate valve is disposed between the growth chamber and the cooling device.

[0021] In some embodiments, step S2 further includes: turning on the gas heater to heat nitrogen, delivering the heated nitrogen to the cooling device through a nitrogen delivery pipeline, and adjusting the flow rate of the heated nitrogen into the cooling device through a solenoid valve or a manual valve on the nitrogen delivery pipeline.

[0022] Step S3 further includes: transporting the phosphorus-containing gas discharged from the cooling equipment to the first processing body through an exhaust gas pipeline, and adjusting the flow rate of the phosphorus-containing gas entering the first processing body through a solenoid valve or a manual valve on the exhaust gas pipeline.

[0023] In some embodiments, the cooling device is a cold trap; wherein in step S1, while opening the first gate valve, the second gate valve is also opened and the third gate valve is closed, and the method further includes: introducing liquid nitrogen into the cold trap and controlling the vacuum level inside the cold trap by a molecular pump, wherein the second gate valve is disposed between the cold trap and the molecular pump, and the third gate valve is disposed between the growth chamber and the cold pump.

[0024] In step S2, closing the first gate valve and the second gate valve isolates the cold trap and the growth chamber. Heated nitrogen is then transported to the cold trap through the nitrogen delivery pipeline. The process further includes: controlling a solenoid valve on the nitrogen delivery pipeline via a controller, or using a manual valve on the nitrogen delivery pipeline, to adjust the flow rate of the heated nitrogen into the cold trap; heating the cold trap; and, in response to the heating temperature of the cold trap, controlling a solenoid valve on the waste gas delivery pipeline via the controller to adjust the flow rate of phosphorus-containing gas to the first processing unit.

[0025] In step S3, the phosphorus-containing gas discharged from the cold trap is transported to the first processing body through the waste gas conveying pipe, and in response to the temperature in the first processing chamber, the flow rate of the phosphorus-containing gas entering the first processing body is adjusted by controlling the solenoid valve on the waste gas conveying pipe through the controller, or by adjusting the manual valve on the waste gas conveying pipe.

[0026] In some embodiments, the cooling device is a cold pump; wherein in step S2, only the third gate valve is closed to isolate the cold pump and the growth chamber, and heated nitrogen is delivered to the cold pump through a nitrogen delivery pipeline, and the method further includes: adjusting the flow rate of heated nitrogen entering the cold pump through a manual valve on the nitrogen delivery pipeline;

[0027] In step S3, the phosphorus-containing gas discharged from the cold pump is transported to the first processing body through the waste gas conveying pipeline, and in response to the temperature in the first processing chamber and the reaction state in the four processing chambers, the flow rate of the phosphorus-containing gas entering the first processing body is adjusted by the manual valve on the waste gas conveying pipeline.

[0028] In some embodiments, the processing equipment further includes a backup processing device, which includes a second water-cooling structure and a transparent second processing body; the second processing body includes a second neutralization tank and a backup first processing chamber, a backup second processing chamber, and a second testing chamber connected in sequence; the backup first processing chamber is used to hold copper sulfate solution; the backup second processing chamber is used to hold potassium permanganate solution; the second testing chamber is used to hold silver nitrate test paper and copper sulfate solution; the second neutralization tank is diaphragmably connected to the backup first processing chamber, the backup second processing chamber, and the second testing chamber, and is used to hold an alkaline solution; the second water-cooling structure is disposed outside the second processing body to cool the second processing body; the recycling method further includes the following steps:

[0029] S4. In response to the reaction status in the four processing cavities of the first processing body and the reaction status in the first inspection cavity, determine whether to add a backup processing device.

[0030] If the backup treatment device is added, the backup first treatment chamber is connected to the first inspection chamber through a pipeline to receive the phosphorus-containing gas discharged from the first inspection chamber, and then sequentially undergoes copper sulfate treatment, potassium permanganate treatment and inspection treatment. The treated waste liquid is then discharged to the second neutralization tank for alkaline neutralization treatment.

[0031] In some embodiments, the recovery process further includes: determining the processing status of phosphorus recovery by monitoring at least one of temperature, vacuum degree, reaction state, color, and turbidity.

[0032] As described above, the phosphorus recovery and treatment system provided in this application can be used as a supporting module for molecular beam epitaxy equipment. It offers significant advantages in safety and processing efficiency when recovering and treating phosphorus-containing gases, and can be industrially applied at a low cost with wide applicability. Specifically, this application, by introducing heated nitrogen gas for purging, assists the cooling equipment in quickly discharging phosphorus-containing gases and solves the problem of phosphorus material residue that may occur during the disassembly of traditional cold traps due to insufficient temperature difference. The transparent treatment unit (such as a first or second treatment unit) allows on-site personnel to intuitively judge the processing status of phosphorus recovery, improving the safety and response efficiency of phosphorus recovery. Furthermore, the treatment equipment does not require the introduction of liquid nitrogen, saving liquid nitrogen materials and reducing the risks of pipe icing and blockage, liquid nitrogen leakage, or frostbite to operators. Additionally, the first treatment unit... The four-stage series reaction tank (cooling down → hydrogen peroxide pre-oxidation → copper sulfate precipitation → acidic potassium permanganate deep oxidation) integrates multiple reaction steps into a single treatment device. This not only simplifies the device structure but also allows for real-time monitoring of the treatment progress and reaction status. Combined with the synergistic effect of nitrogen purging and multi-stage chemical treatment, it effectively solves the problems of low white phosphorus recovery efficiency (residue in traditional cold traps) and high risk of secondary pollution (incomplete single reaction). In particular, the combination with a neutralization tank (either the first or second neutralization tank) significantly improves the efficiency and safety of phosphorus recovery treatment. Attached Figure Description

[0033] The accompanying drawings are provided to better understand this application and do not constitute an undue limitation thereof. Wherein:

[0034] Figure 1 This is a flowchart of a phosphoric acid recovery process provided in this application according to an embodiment;

[0035] Figure 2 This is a front view of the main processing device provided in this application according to an embodiment;

[0036] Figure 3 yes Figure 2 A schematic diagram of the side structure of the main processing unit;

[0037] Figure 4 This is a front view schematic diagram of the backup processing device provided in this application according to an embodiment;

[0038] Figure 5 This is a schematic diagram of the structure of a cold trap and its connected growth chamber according to an embodiment of this application;

[0039] Figure 6 This is a flowchart of the growth chamber baking and cold trap recovery of phosphorus-containing gas according to an embodiment of this application;

[0040] Figure 7 This is a schematic diagram of a phosphorus recovery process based on a cold trap, a solenoid valve, and a controller, according to an embodiment of this application.

[0041] Figure 8 This is a flowchart of a phosphoric acid recovery process based on a cold trap and controller provided in this application according to an embodiment;

[0042] Figure 9 This is a schematic diagram of a phosphorus recovery process based on a cold trap and a manual valve according to an embodiment of this application;

[0043] Figure 10 This is a schematic diagram of a phosphorus recovery process based on a cold pump and a manual valve according to an embodiment of this application;

[0044] Figure 11 This application provides a flowchart of a phosphoric acid recovery process based on a cold trap, a manual valve, and a controller, according to an embodiment.

[0045] Figure 12 This is a flowchart of a phosphoric acid recovery process based on a cold pump, a manual valve, and a controller, provided according to an embodiment of this application.

[0046] [The following are explanations of the reference numerals in the attached drawings]: 100 - Main processing unit, 110 - First processing chamber, 111 - First conduit, 112 - First air inlet connection, 113 - Baffle plate, 114 - First outlet, 115 - First thermocouple, 116 - First filling port, 117 - Porous distributor, 120 - Second processing chamber, 121 - Second conduit, 122 - Second filling port, 130 - Third processing chamber, 131 - Third conduit, 132 - Third filling port, 140 - Fourth processing chamber, 141 - Fourth conduit, 142- Fourth filling port, 150- First testing chamber, 151- Fifth conduit, 152- First test paper box, 153- First air outlet, 160- First water cooling structure, 161- First liquid inlet, 162- First liquid outlet, 170- First neutralization tank, 171- First drain outlet, 200- Backup processing device, 210- Backup first processing chamber, 211- Backup first conduit, 212- Second air inlet, 213- Backup baffle, 214- Second outlet. 215-Spare first filling port, 220-Spare second processing chamber, 221-Spare second conduit, 222-Spare second filling port, 230-Second testing chamber, 231-Spare third conduit, 232-Second test paper box, 233-Second air outlet, 240-Second water cooling structure, 241-Second liquid inlet, 242-Second liquid outlet, 250-Second neutralization tank, 251-Second drain port, 300-Cold trap, 301-First gate valve, 302-Connecting pipe, 303-Second Gate valve, 304-Molecular pump, 311-Liquid inlet, 312-Nitrogen purging port, 313-Second thermocouple, 314-Nitrogen vent port, 315-Vacuum gauge, 316-Heating plate, 317-Waste gas vent port, 400-Growth chamber, 500-Gas heater, 501-Inlet pipe, 502-Nitrogen delivery pipe, 503-Waste gas delivery pipe, 600-Solenoid valve, 700-Manual valve, 800-Controller, 801-Third gate valve, 802-Three-way valve, 900-Cold pump. Detailed Implementation

[0047] To make the objectives, advantages, and features of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this application.

[0048] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show components related to this application and are not drawn according to the actual number, shape, and size of components in the implementation. In actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0049] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of this application must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, where implementation is possible, those skilled in the art can selectively implement some or all of the technical features in any embodiment, or selectively implement a combination of some or all of the technical features in multiple embodiments, based on the disclosure of this application and depending on design specifications or implementation requirements, thereby increasing the flexibility in implementing this application.

[0050] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “multiple” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “installed,” “connected,” and “linked” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be mechanical or electrical. Connections can be direct or indirect through an intermediate medium, and can be internal communication between two elements or an interaction between two elements. Relational terms such as “first,” “second,” “third,” “fourth,” etc., are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor do they indicate or imply relative importance or implicitly specify the number of indicated technical features. It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying 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, and therefore should not be construed as a limitation of this application. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. The implementation of the rotary connection described herein can be a hinge or other various common rotary connection methods, which this application does not limit.

[0051] One of the objectives of this application is to provide a phosphorus recovery system to solve one or more technical problems existing in the current phosphorus recovery process for molecular beam epitaxy.

[0052] The second objective of this application is to provide a phosphorus recovery process implemented by a phosphorus recovery system, which aims to improve the efficiency and safety of phosphorus-containing gas treatment after molecular beam epitaxy.

[0053] The phosphorus recovery and treatment system includes a cooling device and a processing device. The cooling device can be either a cold trap or a cold pump. The cooling device is connectable to the growth chamber of the molecular beam epitaxy (MBE) equipment. The cooling device is configured to receive heated nitrogen gas after the growth chamber has been baked, so that the heated nitrogen gas can be used to purge phosphorus-containing gases from the inside of the cooling device and expel them. The processing device includes a main processing unit, which is detachably connected to the cooling device. Optionally, the processing device also includes a backup processing unit for secondary recovery treatment.

[0054] The following description is in conjunction with the accompanying drawings.

[0055] This application provides a phosphorus recovery method performed by a phosphorus recovery system, which includes the following steps:

[0056] S1. Connect the growth chamber and the cooling equipment to make the pressure inside the cooling equipment lower than atmospheric pressure, and drive the phosphorus material in the growth chamber into the cooling equipment by baking. In this step, if the cooling equipment is a cold trap, liquid nitrogen needs to be filled in for cooling, while if the cooling equipment is a cold pump, liquid nitrogen is not required.

[0057] S2. Isolate the growth chamber and cooling equipment, and introduce heated nitrogen into the cooling equipment to purge the phosphorus-containing gas inside the cooling equipment and discharge it to the outside.

[0058] S3. The phosphorus-containing gas discharged from the cooling equipment is transported to the first processing body of the main treatment unit, and undergoes cooling treatment, hydrogen peroxide treatment, copper sulfate treatment, potassium permanganate treatment and inspection treatment in sequence. Finally, the waste liquid is discharged to the first neutralization tank for alkaline neutralization treatment.

[0059] More detailed, through Figure 1 To illustrate the process, before the maintenance of the growth chamber (i.e., the molecular beam epitaxy reaction chamber) is completed, the following steps are performed sequentially:

[0060] S1. The growth chamber is baked at high temperature to drive the phosphorus-containing gas in the growth chamber into the cooling equipment;

[0061] S2. After the growth chamber is baked, isolate the growth chamber from the cooling equipment, connect the cooling equipment to the main processing unit, and purge the cooling equipment with heated nitrogen gas to purge the phosphorus-containing gas in the cooling equipment to the main processing unit.

[0062] S3. After the phosphorus-containing gas is purged to the main processing unit, it undergoes the following steps in sequence:

[0063] a. Cooling treatment, including: rapidly cooling the high-temperature phosphorus-containing gas to below a safe temperature using cooling water to prevent white phosphorus from entering the auto-ignition temperature range, destroying the necessary conditions for the white phosphorus combustion reaction, and preventing the high-temperature white phosphorus vapor from coming into contact with air and causing deflagration; the temperature of the cooling water is lower than the auto-ignition temperature of white phosphorus; as an example, the temperature of the cooling water is <50°C; the cooling water is selected from industrial cooling circulating water such as deionized water, pure water, or distilled water, and there are no restrictions on this.

[0064] b. Hydrogen peroxide treatment, including: treating the cooled phosphorus-containing gas with hydrogen peroxide solution to oxidize white phosphorus into stable phosphate, eliminating the natural and toxic risks of white phosphorus; this reaction is relatively mild and is particularly suitable for small-scale or preliminary white phosphorus treatment. This reaction is carried out under alkaline or neutral conditions, and the chemical reaction equation is: P4 + 10H2O2 → 4H3PO4 + 4H2O.

[0065] c. Copper sulfate treatment includes: treating hydrogen peroxide-treated gas with copper sulfate (CuSO4) solution to oxidize and reduce unreacted white phosphorus, converting it into cuprous phosphide (Cu3P) precipitate, phosphoric acid, and sulfuric acid. This rapidly fixes the activity of white phosphorus, preventing the risk of spontaneous combustion, and simultaneously generates insoluble Cu3P precipitate, facilitating subsequent precipitation separation. The reaction mechanism is that white phosphorus reacts with copper sulfate under acidic conditions. The concentration of the copper sulfate solution can be adjusted according to the white phosphorus content. For example, a copper sulfate solution with a mass percentage of 5%-10% can be selected and adjusted to an acidic environment (pH < 7). An acidic environment is conducive to accelerating phosphorus oxidation and ensuring the stability of the Cu3P precipitate. For acid control, for example, the initial pH is adjusted to 2-3 (which can be achieved by adding dilute sulfuric acid) to suppress side reactions (such as the formation of elemental copper).

[0066] The chemical reaction equation for this process is: 11P + 15CuSO4 + 24H2O → 5Cu3P↓ + 6H3PO4 + 15H2SO4. The setting of the copper sulfate solution concentration and pH value helps to increase the reaction rate and efficiency. In some embodiments, during copper sulfate treatment, reaction endpoint monitoring can be provided. Since the turbidity of the copper sulfate solution is positively correlated with the amount of Cu3P precipitation, the reaction termination time can be determined by observing the change in the turbidity of the copper sulfate solution (corresponding to the amount of precipitation). This method can replace traditional sampling and detection, reducing the risk of operator exposure and improving operational safety.

[0067] d. Potassium permanganate treatment, including: treating copper sulfate-treated gases with acidic potassium permanganate (KMnO4) solution to deeply decompose phosphides and eliminate the risk of generating highly toxic PH3 gas; the reaction mechanism is that, under acidic conditions, potassium permanganate oxidizes residual cuprous phosphide and unreacted white phosphorus to phosphoric acid, and the chemical reaction equation is: 3P + 5KMnO4 + 9H2SO4 → 5MnSO4 + 3H3PO4 + K2SO4 + 4H2O;

[0068] The concentration of the potassium permanganate solution can be adjusted according to actual conditions. For example, a potassium permanganate solution with a molar ratio of 0.1-0.5 mol / L can be selected and adjusted to an acidic environment (pH < 7), for example, pH < 2 (by adding sulfuric acid). In some embodiments, during potassium permanganate treatment, the reaction endpoint can be monitored. After the potassium permanganate reaction, the solution undergoes a color change; the fading of the purplish-red color indicates that the oxidation reaction is complete (KMnO4 is reduced to Mn). 2 +);

[0069] e. Testing, including: testing whether the white phosphorus material has been cleaned by using silver nitrate test paper and copper sulfate (CuSO4) solution. Specifically, observe the color change of silver nitrate test paper and the turbidity change of copper sulfate solution (amount of precipitate formation) to determine the reaction termination time.

[0070] f. Waste liquid neutralization treatment, including: neutralizing acidic waste liquid with alkaline solution and generating phosphate precipitate (waste liquid harmless treatment); the reaction mechanism is to neutralize acidic waste liquid (H3PO4) with sodium hydroxide (NaOH) solution or saturated lime milk (Ca(OH)2) solution, converting phosphoric acid into calcium phosphate or sodium phosphate precipitate. The chemical reaction equations are: H3PO4 + 3NaOH → Na3PO4↓ + 3H2O, or 2H3PO4 + 3Ca(OH)2 → Ca3(PO4)2↓ + 6H2O; in this way, the pH of the waste liquid can be adjusted to neutral (6-8), avoiding corrosiveness, and the phosphate precipitate can be recovered or safely discharged.

[0071] In some embodiments, the above-mentioned waste liquid neutralization treatment further includes: determining the endpoint of the neutralization reaction using an indicator. As an example, phenolphthalein indicator is used for titration; if the waste liquid turns pink, it indicates that neutralization is complete. In some embodiments, the waste liquid neutralization treatment further includes: setting up a turbidity sensor to monitor the amount of calcium phosphate or sodium phosphate precipitate. Therefore, during waste liquid neutralization treatment, the neutralization status can be determined in real time through certain monitoring methods, improving the safety and response efficiency of waste liquid treatment.

[0072] This application provides multiple monitoring methods to determine the processing status of phosphorus recovery in real time, thereby improving the safety and response efficiency of the phosphorus recovery stage. Specifically, the processing status of phosphorus recovery is determined by monitoring at least one of the following: temperature, vacuum level, reaction state, color, and turbidity.

[0073] Next, the phosphorus recovery and treatment system provided in this application and the recovery and treatment method implemented thereunder will be further described.

[0074] Figure 2 This is a front view structural diagram of the main processing device 100 provided according to some embodiments of this application. Figure 3 yes Figure 2 A schematic diagram of the side structure of the main processing unit 100. (See attached diagram.) Figure 2 and Figure 3 As shown, the processing equipment includes a main processing unit 100, which is detachably connected to a cooling device. Thus, the main processing unit 100 processes the white phosphorus-containing waste gas purged from the growth chamber 400 and the cooling device.

[0075] The main processing unit 100 includes a transparent first processing body. This first processing body can be made of any transparent material, such as acrylic sheet or quartz glass. Further, the surface of the acrylic sheet or quartz glass is covered with a polytetrafluoroethylene (PTFE) coating. The PTFE coating provides high-temperature resistance and reduces material adhesion and corrosion. Because the first processing body is entirely transparent, it facilitates on-site operators to conduct timely and quantitative observation of the phosphorus recovery process, increasing the safety and response efficiency of phosphorus recovery. For example, by observing the reaction state within the first processing body, the flow rate of phosphorus-containing gas to the main processing unit 100 can be adjusted to address issues of excessively fast or slow reactions. Based on the reaction state, it can also be determined whether to add a backup processing unit 200. Additionally, the reaction termination time can be determined so that the processing equipment can be promptly dismantled, restoring the machine to its working state, and then the processing equipment can be separately treated for harmless disposal. All of these improvements enhance the efficiency and safety of phosphorus recovery.

[0076] Figure 2 The first processing unit comprises a first processing chamber 110, a second processing chamber 120, a third processing chamber 130, a fourth processing chamber 140, and a first inspection chamber 150, which are connected in sequence. These five chambers can be connected in sequence in various ways. The first processing chamber 110 contains cooling water, which, as an example, is purified water with a cooling temperature set to <50°C. The second processing chamber 120 contains hydrogen peroxide solution. The third processing chamber 130 contains copper sulfate solution. The fourth processing chamber 140 contains potassium permanganate solution. The first inspection chamber 150 contains silver nitrate test paper and copper sulfate solution. The first processing chamber 110 directly receives phosphorus-containing gas discharged from the cooling equipment.

[0077] Based on this, after pretreatment by a cooling device, the phosphorus-containing gas is transported to the first processing unit. First, the high-temperature phosphorus-containing gas is cooled by cooling water in the first processing chamber 110, lowering its temperature to below the auto-ignition temperature of white phosphorus. Then, the cooled phosphorus-containing gas undergoes initial treatment with hydrogen peroxide solution (H2O2) in the second processing chamber 120. This not only further reduces the temperature of the phosphorus-containing gas but also oxidizes the white phosphorus to phosphate (H3PO4), resulting in a relatively gentle and safe reaction process. Subsequently, the phosphorus-containing gas treated with hydrogen peroxide is further processed by copper sulfate solution in the third processing chamber 130. Copper sulfate solution is the core reagent for treating white phosphorus vapor. Next, the phosphides are further decomposed by acidic potassium permanganate solution in the fourth processing chamber 140, oxidizing the remaining unreacted white phosphorus gas into phosphoric acid. Then, to verify the phosphorus recovery treatment effect, the reaction endpoint is determined by the changes in silver nitrate test paper and copper sulfate solution in the first test chamber 150. If the reaction endpoint does not meet the requirements, it is connected to the backup treatment device 200 for secondary recovery treatment.

[0078] It should be noted that in titration, the titration endpoint refers to the chemical phenomenon that occurs at the end of the titration reaction. It is determined by the amount of titrant added. The titration endpoint is reached when the titrant reacts completely with the substance being titrated. The reaction endpoint refers to the endpoint that can be observed during the titration experiment, such as a change in color or the formation of a precipitate.

[0079] Figure 2 and Figure 3 In the process, the main processing device 100 further includes a first water-cooling structure 160, and the first processing body further includes a first neutralization tank 170.

[0080] The first water-cooling structure 160 is disposed outside the first processing body to cool the first processing body. In some embodiments, the first water-cooling structure 160 is disposed at the bottom of the first processing body and is configured as a circulating cooling water tank, which can be connected to a small water chiller to reduce the temperature of each processing chamber (110, 120, 130, 140, 150), avoid the temperature rise in the processing chamber, which would affect the processing efficiency, and especially avoid the risk of white phosphorus spontaneous combustion due to temperature rise.

[0081] In some embodiments, the first water-cooling structure 160 has a first liquid inlet 161 and a first liquid outlet 162, wherein the first liquid inlet 161 is used to introduce cooling water and the first liquid outlet 162 is used to discharge cooling water.

[0082] The first neutralization tank 170 is connectable to the first processing chamber 110, the second processing chamber 120, the third processing chamber 130, the fourth processing chamber 140, and the first inspection chamber 150. The first neutralization tank 170 is used to hold an alkaline solution, which is either sodium hydroxide (NaOH) solution or saturated lime milk (Ca(OH)2) solution, to neutralize acidic waste liquid and convert phosphoric acid into phosphate precipitates, such as calcium phosphate or sodium phosphate precipitates, achieving harmless treatment.

[0083] In some embodiments, a phenolphthalein indicator is added to detect the completion status of acid-base neutralization in the first neutralization tank 170. Specifically, phenolphthalein solution is added to the first neutralization tank 170; when the waste liquid turns pink, it indicates that neutralization is complete and the waste liquid can be discharged normally. In some embodiments, a turbidity sensor is provided in the first neutralization tank 170 to detect the amount of phosphate precipitation, thereby determining the neutralization status of the waste liquid. In some embodiments, the first neutralization tank 170 is provided with a first drain port 171, through which the waste liquid with a neutralized pH value is discharged.

[0084] Secondly, refer to Figure 5 and Figure 10 The cooling device is a cold trap 300 or a cold pump 900, which can be switched on and off with the growth chamber 400 of the molecular beam epitaxy equipment. The cooling device is configured such that heated nitrogen is introduced into the growth chamber 400 after baking, and the heated nitrogen is used to purge the phosphorus-containing gas inside the cooling device and discharge it to the outside.

[0085] like Figure 5 As shown, in some embodiments, a first gate valve 301 is provided between the growth chamber 400 and the cold trap 300. Figure 10 As shown, in some other embodiments, a third gate valve 801 is provided between the growth chamber 400 and the cold pump 900. The on / off connection between the growth chamber 400 and the cooling equipment is controlled by the first gate valve 301 or the third gate valve 801.

[0086] refer to Figure 7 ,as well as Figures 9-10 Both the cold trap 300 and the cold pump 900 are connected to a nitrogen delivery pipe 502 and an exhaust gas delivery pipe 503. The nitrogen delivery pipe 502 is used to deliver heated nitrogen to the cold trap 300 or the cold pump 900. The exhaust gas delivery pipe 503 is also connected to the main processing unit 100, and is used to deliver phosphorus-containing gas discharged from the cold trap 300 or the cold pump 900 to the main processing unit 100.

[0087] like Figure 7As shown, in one example, solenoid valves 600 are installed on the nitrogen delivery pipe 502 and the waste gas delivery pipe 503. The solenoid valves 600 are communicatively connected to the controller 800. With this configuration, the controller 800 can control the solenoid valve 600 on the nitrogen delivery pipe 502 to adjust the flow rate of heated nitrogen into the cold trap 300, and can also control the solenoid valve 600 on the waste gas delivery pipe 503 to adjust the flow rate of phosphorus-containing gas into the main treatment unit 100. This allows for precise control of the phosphorus recovery process, improving safety and processing efficiency.

[0088] like Figure 9 and Figure 10 As shown, in one example, manual valves 700 are provided on the nitrogen delivery pipe 502 and the waste gas delivery pipe 503, allowing the controller 800 to be either removed or retained. With this configuration, the flow rate of heated nitrogen entering the cold trap 300 or the cold pump 900 can be manually adjusted via the manual valve 700 on the nitrogen delivery pipe 502, and the flow rate of phosphorus-containing gas entering the main treatment unit 100 can be manually adjusted via the manual valve 700 on the waste gas delivery pipe 503, achieving similar effects as described above.

[0089] Return to reference Figure 2 and Figure 3 In some embodiments, conduits are provided in the first processing chamber 110, the second processing chamber 120, the third processing chamber 130, the fourth processing chamber 140 and the first inspection chamber 150. The function of these conduits is to introduce gas from the previous processing chamber into the current processing chamber.

[0090] For ease of description and understanding, the following conduits are defined: a first conduit 111, a second conduit 121, a third conduit 131, a fourth conduit 141, and a fifth conduit 151. The first conduit 111 is disposed within the first processing chamber 110, with one end connected to the exhaust gas delivery pipe 503 via a first air inlet 112, delivering phosphorus-containing gas to the first processing chamber 110. The second conduit 121 is disposed within the second processing chamber 120, with one end connected to the first processing chamber 110, delivering pre-cooled phosphorus-containing gas to the second processing chamber 120. The third conduit 131 is disposed within the third processing chamber 130, with one end connected to the second processing chamber 120, delivering hydrogen peroxide-treated phosphorus-containing gas to the third processing chamber 130. The fourth conduit 141 is disposed within the fourth processing chamber 140, with one end connected to the third processing chamber 130, delivering copper sulfate-treated phosphorus-containing gas to the fourth processing chamber 140. The fifth conduit 151 is disposed within the first inspection chamber 150, with one end connected to the fourth processing chamber 140, to deliver phosphorus-containing gas treated with potassium permanganate to the first inspection chamber 150. This application, by providing a conduit, facilitates increased gas intake speed, control of the gas intake path, and increased gas-liquid contact time.

[0091] In some embodiments, the bottom of the first conduit 111, the second conduit 121, the third conduit 131, the fourth conduit 141, and the fifth conduit 151 are all provided with a porous distributor 117. The porous distributor 117 in this embodiment has a plurality of small holes, which allow gas to rise in the form of tiny bubbles, increasing the gas-liquid contact time and improving cooling efficiency. As an example, the pore diameter of the porous distributor 117 is 2mm to 3mm. It should be noted that any conduit can release gas through the porous distributor 117, and the end of the conduit away from the inlet can be open or closed.

[0092] In some embodiments, the main processing device 100 further includes baffles 113, with baffles 113 provided in each of the first to fourth processing chambers. The number of baffles 113 in each processing chamber can be adjusted according to actual needs. One end of each baffle 113 is fixed to the chamber wall, and the other end is a free end. The baffles 113 can slow down the gas passage time and improve cooling efficiency. The baffles 113 can be arranged horizontally or inclined relative to the horizontal plane.

[0093] In some embodiments, the first processing chamber 110, the second processing chamber 120, the third processing chamber 130, the fourth processing chamber 140, and the first inspection chamber 150 are each provided with a first discharge outlet 114. Waste liquid from each processing chamber is discharged to a first neutralization tank 170 through the first discharge outlet 114 for harmless treatment. To enable a switchable connection, a valve, preferably a solenoid valve, can be installed at each first discharge outlet 114.

[0094] In some embodiments, the first processing body is provided with a first thermocouple 115, which is used to measure the temperature inside the first processing chamber 110. This arrangement facilitates the dynamic adjustment of the flow rate of phosphorus-containing gas entering the first processing body in response to the temperature monitoring of the first thermocouple 115. For example, if the temperature inside the first processing chamber 110 is too high, the gas flow rate is reduced.

[0095] In some embodiments, the top of the first processing chamber 110 is provided with a first filling port 116 for adding cooling water into the first processing chamber 110. In some embodiments, the top of the second processing chamber 120 is provided with a second filling port 122 for adding hydrogen peroxide into the second processing chamber 120. In some embodiments, the top of the third processing chamber 130 is provided with a third filling port 132 for adding copper sulfate solution into the third processing chamber 130. In some embodiments, the top of the fourth processing chamber 140 is provided with a fourth filling port 142 for adding potassium permanganate solution into the fourth processing chamber 140.

[0096] In some embodiments, the top of the first test chamber 150 is provided with a first test strip box 152, which can hold silver nitrate test strips. Furthermore, the upper opening of the first test strip box 152 allows for the addition and replacement of test strips.

[0097] In some embodiments, the side of the first test chamber 150 is provided with a first gas outlet 153 for discharging the gas processed by the main processing device 100 through a pipeline or connecting it to the backup processing device 200.

[0098] As can be seen from the above, the main processing device 100 provided in this application is equipped with four-stage series reaction tanks (110, 120, 130, 140), which sequentially realize cooling and temperature reduction → hydrogen peroxide pre-oxidation → copper sulfate precipitation → potassium permanganate deep oxidation. By integrating multiple reaction steps into the same main processing device 100, the progress and reaction status of the phosphorus recovery process can be observed at any time, improving the safety and response efficiency of phosphorus recovery. In particular, the combined external first neutralization tank 170 further enhances the processing efficiency and safety.

[0099] Furthermore, considering the exceptionally high amount of white phosphorus exceeding the load of the main treatment unit 100, and the detection of incompletely treated gas in the first inspection chamber 150, a backup treatment unit 200 was added. When needed, the backup treatment unit 200 is connected to the main treatment unit 100 via a pipeline for secondary treatment of the white phosphorus-containing waste gas. It should be noted that the structure and operation of the backup treatment unit 200 are basically the same as those of the main treatment unit 100; the following mainly focuses on the differences between the two.

[0100] Figure 4 This is a front view structural schematic diagram of a backup processing device 200 provided according to some embodiments of this application. In use, the backup processing device 200 and the main processing device 100 are detachably connected. Figure 4 As shown, the backup processing device 200 includes a second processing body, which includes a backup first processing chamber 210, a backup second processing chamber 220 and a second inspection chamber 230 connected in sequence, reducing the number of chambers by two compared to the main processing device 100.

[0101] The backup first processing chamber 210 has the same structure and function as the aforementioned third processing chamber 130. The backup first processing chamber 210 contains a copper sulfate (CuSO4) solution, which serves as the core reagent for treating white phosphorus vapor. The backup first processing chamber 210 is used to receive gas discharged from the first inspection chamber 150.

[0102] The structure and function of the backup second processing chamber 220 are the same as or similar to those of the aforementioned fourth processing chamber 140. The backup second processing chamber 220 contains an acidic potassium permanganate (KMnO4) solution to deeply decompose phosphides and oxidize residual unreacted white phosphorus gas into phosphoric acid.

[0103] The structure and implementation of the second test chamber 230 are basically the same as those of the first test chamber 150. The reaction endpoint is determined by observing the turbidity change (precipitate formation) of silver nitrate test paper and copper sulfate solution. For example, a second test paper box 232 is placed on the top of the second test chamber 230. The second test paper box 232 contains silver nitrate test paper and has an opening at the top for adding and replacing test paper.

[0104] The backup processing device 200 further includes a second water-cooling structure 240, and the second processing body further includes a second neutralization tank 250. The second neutralization tank 250 is intermittently connected to the backup first processing chamber 210, the backup second processing chamber 220, and the second inspection chamber 230. The second neutralization tank 250 is used to hold an alkaline solution, as described above. The second water-cooling structure 240 is disposed outside the second processing body to cool it.

[0105] Similar to the first water-cooling structure 160, the second water-cooling structure 240 has a second liquid inlet 241 and a second liquid outlet 242, wherein the second liquid inlet 241 is used to introduce cooling water and the second liquid outlet 242 is used to discharge cooling water.

[0106] In some embodiments, the second water-cooling structure 240 is disposed at the bottom of the second processing body, which is equivalent to a circulating cooling water tank. It can be connected to a small water chiller to reduce the temperature of each processing chamber (210, 220, 230), avoid the temperature rise in the processing chamber, and avoid the processing efficiency, especially the risk of white phosphorus spontaneous combustion caused by temperature rise.

[0107] In some embodiments, the second neutralization tank 250 is provided with a second drain port 251, through which waste liquid with a pH value adjusted to neutral is discharged. It should be noted that the second neutralization tank 250 is used in a similar manner to the first neutralization tank 170. For example, the neutralization completion status can be detected by using a phenolphthalein indicator, and the amount of phosphate precipitation can be detected by using a turbidity sensor.

[0108] In some embodiments, the backup first processing chamber 210, the backup second processing chamber 220, and the second inspection chamber 230 are each provided with backup conduits. The function of these backup conduits is to introduce waste gas from the previous processing chamber into the current processing chamber. For ease of description and understanding, backup first conduit 211, backup second conduit 221, and backup third conduit 231 are defined.

[0109] The backup first conduit 211 is disposed within the backup first processing chamber 210, with one end connected to a pipe via a second air inlet 212. This pipe is connected to the main processing device 100, such as the first air outlet 153, thereby conveying the residual gas after processing by the main processing device 100 to the backup first processing chamber 210. The backup second conduit 221 is disposed within the backup second processing chamber 220, with one end connected to the backup first processing chamber 210, conveying the gas treated with copper sulfate solution to the backup second processing chamber 220. The backup third conduit 231 is disposed within the second inspection chamber 230, with one end connected to the backup second processing chamber 220, conveying the gas treated with potassium permanganate solution to the second inspection chamber 230.

[0110] In some embodiments, the bottom of the backup first conduit 211, backup second conduit 221, and backup third conduit 231 are all provided with a porous distributor 117, allowing gas to rise in the form of microbubbles, increasing the gas-liquid contact time and improving cooling efficiency. It should be noted that any backup conduit can release gas through the porous distributor 117, and the end of the backup conduit away from the inlet can be open or closed.

[0111] In some embodiments, the backup processing device 200 further includes a backup baffle 213. Each of the first and second backup processing chambers is equipped with a backup baffle 213, and the number of backup baffles 213 in each processing chamber can be adjusted according to actual needs. The function and implementation of the backup baffle 213 are similar to those of the aforementioned baffle 113, and will not be described again.

[0112] In some embodiments, the backup first processing chamber 210, the backup second processing chamber 220, and the second inspection chamber 230 are each provided with a second discharge outlet 214. Waste liquid from each backup processing chamber is discharged to a second neutralization tank 250 through the second discharge outlet 214 for harmless treatment. A valve, preferably a solenoid valve, may be installed at each second discharge outlet 214.

[0113] It should be noted that in this embodiment, the backup processing device 200 does not require thermocouples, unlike the main processing device 100. As an example, both the first and second processing bodies are made of polytetrafluoroethylene coated acrylic sheets, which combine corrosion resistance and visual monitoring functions, making them particularly suitable for complex chemical environments and ensuring reliable and stable operation of the device.

[0114] In some embodiments, the top of the backup first processing chamber 210 is provided with a backup first filling port 215 for adding copper sulfate solution to the backup first processing chamber 210. In some embodiments, the top of the backup second processing chamber 220 is provided with a backup second filling port 222 for adding potassium permanganate solution to the backup second processing chamber 220. In some embodiments, the side of the second inspection chamber 230 is provided with a second gas outlet 233 for discharging the processed gas through a pipe.

[0115] like Figure 5 As shown, when the cooling device is a cold trap 300, liquid nitrogen is introduced into the cold trap 300 to adsorb the white phosphorus in the growth chamber 400. Simultaneously, the cold trap 300 is also connected to a molecular pump 304. Specifically, a first gate valve 301 is installed between the cold trap 300 and the growth chamber 400, and a second gate valve 303 is installed between the cold trap 300 and the molecular pump 304. The cold trap 300 and the growth chamber 400 are connected via a connecting pipe 302, on which the first gate valve 301 is installed.

[0116] The first gate valve 301 serves as a control valve between the growth chamber 400 and the cold trap 300, and its on / off state determines the connection state between the two. The on / off state of the second gate valve 303 determines the connection state between the cold trap 300 and the molecular pump 304. The molecular pump 304 is mainly used to maintain the vacuum level of the cold trap 300, or in other words, to keep the pressure inside the cold trap 300 below atmospheric pressure, thereby reducing the risk of spontaneous combustion of white phosphorus.

[0117] Continue to refer to Figure 5 The cold trap 300 has a nitrogen purging port 312, an exhaust port 317, a liquid inlet port 311, and a nitrogen exhaust port 314. The cold trap 300 has a first state and a second state. In the first state, liquid nitrogen needs to be introduced. At this time, the nitrogen purging port 312 and the exhaust port 317 are closed, and the liquid inlet port 311 and the nitrogen exhaust port 314 are opened. The liquid inlet port 311 is connected to a liquid nitrogen inlet pipe to input liquid nitrogen, and the nitrogen exhaust port 314 is connected to an exhaust pipe to discharge nitrogen gas. Thus, when the growth chamber 400 is baked, liquid nitrogen is introduced to cool the cold trap 300, causing the phosphorus-containing gas inside the growth chamber 400 to condense on the inner wall of the cold trap 300. After the growth chamber 400 has finished baking, switch to the second state. In the second state, heated nitrogen needs to be introduced. At this time, close the liquid inlet 311 and the nitrogen outlet 314, open the nitrogen purging port 312 and the exhaust port 317, and connect the nitrogen purging port 312 to the nitrogen delivery pipe 502 and the exhaust port 317 to the exhaust pipe 503.

[0118] In some embodiments, the cold trap 300 is provided with at least one of a heating plate 316, a second thermocouple 313, and a vacuum gauge 315.

[0119] The heating plate 316 is configured to heat the cold trap 300 after the growth chamber 400 has completed baking, thereby assisting in the removal of white phosphorus inside. It is understood that after closing the first gate valve 301 and the second gate valve 303, the solid white phosphorus in the cold trap 300 is vaporized after heating and baking, facilitating its removal and effectively solving the additional problem of white phosphorus residue. The heating plate 316 can be connected to a power controller to heat and bake the cold trap 300.

[0120] When the cold trap 300 is heated, the internal temperature of the cold trap 300 is monitored by the second thermocouple 313 to prevent the white phosphorus from spontaneously combusting due to excessively high internal temperature. As an example, the top of the cold trap 300 is provided with a thermocouple connection port for installing the second thermocouple 313.

[0121] The vacuum gauge 315 is used to measure the vacuum level inside the cold trap 300 to ensure that the vacuum level inside the cold trap 300 is maintained at a safe level.

[0122] The phosphorus recovery process will be further explained below.

[0123] In this embodiment of the application, when the growth chamber 400 is being baked, the first gate valve 301 and the second gate valve 303 are opened to connect the growth chamber 400 and the cold trap 300. During this process, the content of white phosphorus in the growth chamber 400 can be monitored by a residual gas analyzer in the growth chamber 400, and the first gate valve 301 and the second gate valve 303 are closed in response to the white phosphorus content in the growth chamber 400 reaching a safe value.

[0124] like Figure 6 As shown, as an example, when the cooling device is a cold trap 300, the recovery process performed by the phosphorus recovery system includes the following steps:

[0125] S11. Remove the spare parts that are not resistant to baking and prepare for high-temperature baking in the growth chamber at 400°C;

[0126] S12. Open the first gate valve 301 and the second gate valve 303, connect the liquid inlet port 311 on the cold trap 300 to the liquid nitrogen inlet pipe, and connect the nitrogen vent port 314 to the exhaust pipe. Liquid nitrogen is introduced into the cold trap 300, and the vacuum degree inside the cold trap 300 is monitored by the vacuum gauge 315. With this setting, the high-temperature vapor containing white phosphorus is condensed and solidified by liquid nitrogen, realizing the efficient condensation and recovery of white phosphorus. The vacuum degree is monitored in real time to ensure the sealing of the cold trap 300 and prevent air from seeping in. At the same time, after the second gate valve 303 is opened, the vacuum degree inside the cold trap 300 is maintained by the molecular pump 304 to prevent the escape of white phosphorus due to pressure fluctuations.

[0127] S13. Bake the growth chamber 400 and monitor the white phosphorus content in the growth chamber 400 using an RGA (Residual Gas Analyzer) inside the growth chamber 400.

[0128] S14. After the white phosphorus content in the growth chamber 400 reaches a safe value, close the first gate valve 301 and the second gate valve 303 to prepare for the heating of the cold trap 300 and subsequent phosphorus recovery.

[0129] The closed-loop process described above—high-temperature baking, liquid nitrogen cooling and capture, dynamic monitoring, and heated nitrogen-assisted venting—minimizes the risk of white phosphorus exposure. In particular, nitrogen purging avoids the risk of combustion and explosion associated with manual phosphorus extraction and the instantaneous deflagration caused by oxygen contamination. Secondly, liquid nitrogen only needs to be introduced into the cold trap 300 once, eliminating the need to introduce liquid nitrogen into the phosphorus recovery system, thus saving on liquid nitrogen consumption and reducing usage costs. Furthermore, the operation of the first gate valve 301 and the second gate valve 303 can be integrated into a PLC system, automatically starting and stopping the nitrogen purging process based on RGA data. This process, through multiple protection mechanisms, significantly improves the safety of white phosphorus recovery and ensures equipment sealing and control accuracy.

[0130] Therefore, when using the cold trap 100, the growth chamber baking requires opening the first gate valve 301 and the second gate valve 303, and then closing them after the baking is complete. However, when using the cold pump 900, the growth chamber baking only requires opening the third gate valve 801, and then closing it after the baking is complete. It should be noted that when the cooling device is the cold trap 300, the third gate valve 801 also needs to be closed during growth chamber baking. The third gate valve 801 is located between the growth chamber 400 and the cold pump 900. The cold pump 900 is essentially a pump unit that maintains the vacuum state of the growth chamber 400, and in special circumstances, it can replace the cold trap 300.

[0131] In some embodiments, after the growth chamber has been baked, when heating nitrogen, the process further includes: turning on the gas heater 500 to heat the nitrogen, and then delivering the heated nitrogen to the cold trap 300 or the cold pump 900 through the nitrogen delivery pipe 502.

[0132] like Figure 5 and Figure 7 As shown, in some embodiments, the first gate valve 301 and the second gate valve 303 are closed to isolate the cold trap 300 and the growth chamber 400. Nitrogen gas is heated by the gas heater 500 and then transported to the cold trap 300 through the nitrogen gas delivery pipe 502. Further, when heating the nitrogen gas, the solenoid valve 600 on the nitrogen gas delivery pipe 502 is controlled by the controller 800 to automatically adjust the flow rate of the heated nitrogen gas entering the cold trap 300.

[0133] Furthermore, when heating and baking the cold trap 300, the controller 800 can control the solenoid valve 600 on the exhaust gas delivery pipe 503 to automatically adjust the flow rate of phosphorus-containing gas to the first treatment body in response to the temperature monitoring of the second thermocouple 313 on the cold trap 300.

[0134] Furthermore, during the recycling process, in response to the temperature monitoring of the first thermocouple 115 on the first processing chamber 110, the controller 800 controls the solenoid valve 600 on the waste gas conveying pipe 503 to automatically adjust the flow rate of phosphorus-containing gas entering the first processing body.

[0135] like Figure 10 As shown, in some other embodiments, only the third gate valve 801 is closed, isolating the cold pump 900 and the growth chamber 400, and nitrogen is heated by the gas heater 500, and then the heated nitrogen is delivered to the cold pump 900 through the nitrogen delivery pipe 502. It should be noted that in this case, since there is no cold trap 300, there is also no first gate valve 301 and second gate valve 302.

[0136] Furthermore, when heating nitrogen, the flow rate of heated nitrogen entering the cold pump 900 is manually adjusted via the manual valve 700 on the nitrogen delivery pipeline 502.

[0137] Furthermore, in response to temperature monitoring by the first thermocouple 115 on the first processing chamber 110, the flow rate of phosphorus-containing gas entering the first processing body can be manually adjusted via the manual valve 700 on the exhaust gas delivery pipe 503.

[0138] Return to reference Figure 7 When the cooling device is a cold trap 300, the exhaust port 317 on the cold trap 300 is connected to the first air inlet 112 of the main processing device 100 via an exhaust gas delivery pipe 503. The end of the nitrogen delivery pipe 502 furthest from the cold trap 300 is connected to a gas heater 500. The function of the gas heater 500 is to heat the high-purity nitrogen used for purging. The gas heater 500 is connected to an air inlet pipe 501, which is used to input nitrogen into the gas heater 500. After being heated by the gas heater 500, the nitrogen is discharged to the cold trap 300 via the nitrogen delivery pipe 502.

[0139] In this embodiment of the application, when a cold trap 300 is used, the controller 800 controls the opening and closing of the solenoid valve 600 on the waste gas conveying pipeline 503 based on the temperature monitoring of the main processing device 100 and / or the temperature monitoring of the cold trap 300, thereby controlling the flow rate of phosphorus-containing gas to the main processing device 100.

[0140] like Figure 8As shown, as an example, when the cooling device is a cold trap 300, the recovery process performed by the phosphorus recovery system includes the following steps:

[0141] (1) When the growth chamber 400 is being baked, the first gate valve 301 and the second gate valve 302 are opened, the vacuum level inside the cold trap 300 is maintained by the molecular pump 304, and liquid nitrogen is introduced into the cold trap 300.

[0142] (2) After the growth chamber 400 has finished baking, close the first gate valve 301 and the second gate valve 303, remove the liquid nitrogen inlet pipe and the exhaust pipe, and connect the nitrogen purging port 312 and the exhaust port 317.

[0143] (3) Turn on the gas heater 500, turn on the controller 800, control the solenoid valve 600 on the nitrogen delivery pipeline 502, and adjust the flow rate of the heated nitrogen into the cold trap 300.

[0144] (4) Heat and bake the cold trap 300. Based on the temperature monitoring of the second thermocouple 313 on the cold trap 300, control the solenoid valve 600 on the waste gas conveying pipe 503 through the controller 800 to adjust the flow rate of white phosphorus gas to the main treatment device 100.

[0145] (5) Based on the temperature monitoring of the first thermocouple 115 on the main processing unit 100, the solenoid valve 600 on the waste gas conveying pipeline 503 is controlled by the controller 800 to dynamically adjust the gas flow rate entering the main processing unit 100.

[0146] (6) Based on the reaction status in each chamber of the main processing device 100 and the reaction status of the test paper and solution in the test chamber, determine whether to add a backup processing device 200.

[0147] (7) Add a backup treatment device 200 or perform alkaline neutralization and harmless treatment of the main treatment device 100.

[0148] In this way, the problems of low efficiency and high risk of secondary pollution in white phosphorus recovery are solved by the synergistic effect of nitrogen purging and multi-stage chemical treatment. In particular, a backup treatment device 200 can be provided as a redundant treatment device according to the real-time reaction situation.

[0149] like Figure 10 As shown, when a cold pump 900 is used instead of a cold trap 300, a third gate valve 801 is provided between the cold pump 900 and the growth chamber 400, and the cold pump 900 is connected to a nitrogen delivery pipeline 502 and a waste gas delivery pipeline 503 through a three-way valve 802, which can realize the nitrogen purging of the cold pump 900 and also discharge the phosphorus-containing gas in the cold pump 900 to the main processing device 100.

[0150] Therefore, there are two methods for phosphorus recovery: the first is recovery through cold trap 300, and the second is recovery through cold pump 900. There are also two control methods: the first is manual control, and the second is control by controller 800.

[0151] like Figure 11 As shown, as an example, the recovery process performed by the phosphorus recovery system includes the following steps:

[0152] (1) After the growth chamber 400 has finished baking, close the first gate valve 301 and the second gate valve 303, and remove the liquid nitrogen inlet pipe and exhaust pipe on the cold trap 300, and connect the nitrogen purging port 312 and the exhaust port 317.

[0153] (2) Turn on the gas heater 500 and adjust the flow rate of heated nitrogen into the cold trap 300 by controlling the manual valve 700 on the nitrogen delivery pipeline 502.

[0154] (3) Heat and bake the cold trap 300, and monitor the vacuum level and temperature of the cold trap 300;

[0155] (4) Based on the temperature monitoring of the first thermocouple 115 on the main processing unit 100, the flow rate of the gas flowing into the main processing unit 100 is manually adjusted through the manual valve 700 on the waste gas conveying pipeline 503.

[0156] (5) Based on the reaction status in the four processing chambers of the main processing device 100, and the reaction status of silver nitrate test paper and copper sulfate solution in the first test chamber, determine whether to add a backup processing device 200.

[0157] (6) Add a backup treatment device 200 or perform alkaline neutralization and harmless treatment in the main treatment device 100.

[0158] like Figure 12 As shown, as an example, the recovery process performed by the phosphorus recovery system includes the following steps:

[0159] (1) After the growth chamber 400 has finished baking, only the third gate valve 801 is closed;

[0160] (2) Turn on the gas heater 500 and manually adjust the gas flow rate of heated nitrogen into the cold pump 900 through the manual valve 700 on the nitrogen delivery pipeline 502.

[0161] (3) After heating, nitrogen is purged to purge the white phosphorus adsorbed in the cold pump 900 to the main treatment unit 100.

[0162] (4) Based on the temperature of the first thermocouple 115 on the main processing device 100 and the reaction status in each chamber, the flow rate of the gas flowing into the main processing device 100 is manually adjusted through the manual valve 700 on the waste gas conveying pipe 503.

[0163] (5) Based on the reaction status in each chamber of the main processing device 100, and the reaction status of the silver nitrate test paper and copper sulfate solution in the test chamber, determine whether to add a backup processing device 200.

[0164] (6) Add a backup treatment device 200 or perform alkaline neutralization and harmless treatment in the main treatment device 100.

[0165] In summary, the phosphorus recovery system and its implemented recovery method provided in this application have at least the following beneficial effects:

[0166] By adjusting valves (solenoid or manual valves), the gas flow rate is regulated, precisely controlling the reaction rate of white phosphorus-containing gases in each processing chamber, thus improving processing efficiency. Baffles or backup baffles increase gas-liquid contact time, effectively promoting reaction efficiency and improving processing quality. A pH indicator is integrated into the first or second neutralization tank to monitor waste liquid neutralization in real time, ensuring complete neutralization and better achieving harmless treatment. Hot nitrogen purging accelerates the release of white phosphorus-containing gases from the cooling equipment, solving the problem of white phosphorus residue that may occur during traditional cold trap disassembly due to insufficient temperature difference, thus improving white phosphorus recovery efficiency. The main processing unit integrates multiple reaction steps such as cooling, hydrogen peroxide pre-oxidation, copper sulfate precipitation, and deep oxidation with acidic potassium permanganate, allowing for continuous monitoring of processing progress and ensuring treatment effectiveness. An external neutralization tank enhances processing efficiency and safety. A backup processing unit serves as a safety mechanism, ensuring continuous processing in emergencies. Multiple monitoring methods, such as vacuum monitoring, temperature monitoring, reagent monitoring, and visual monitoring, allow for real-time assessment of the phosphorus recovery processing status, improving the safety and response efficiency of phosphorus recovery.

[0167] Therefore, the phosphorus recovery and treatment system provided in this application significantly improves the efficiency and safety of handling phosphorus-containing gases in molecular beam epitaxy processes through various technologies and design optimizations.

[0168] While this application discloses the above, it is not limited thereto. Those skilled in the art can make various modifications and variations to this application without departing from its spirit and scope. Therefore, this application also intends to include any modifications and variations that fall within the scope of this application's specification and its equivalents.

Claims

1. A phosphorus recovery and treatment system, characterized in that, include: A cooling device is connected to the growth chamber of the molecular beam epitaxy equipment in a switchable manner. The cooling device is configured to input heated nitrogen gas after the growth chamber has been baked, so as to use the heated nitrogen gas to purge the phosphorus-containing gas inside the cooling device and discharge it to the outside. And processing equipment, including a main processing unit, which is detachably connected to the cooling equipment; The main processing device includes a first water-cooling structure and a transparent first processing body. The first processing body includes a first neutralization tank and a first processing chamber, a second processing chamber, a third processing chamber, a fourth processing chamber, and a first testing chamber connected in sequence. The first processing chamber is used to hold cooling water. The second processing chamber is used to hold hydrogen peroxide solution. The third processing chamber is used to hold copper sulfate solution. The fourth processing chamber is used to hold potassium permanganate solution. The first testing chamber is used to hold silver nitrate test paper and copper sulfate solution. The first processing chamber is used to receive phosphorus-containing gas discharged from the cooling device. The first neutralization tank is diaphragmably connected to the first processing chamber, the second processing chamber, the third processing chamber, the fourth processing chamber, and the first testing chamber. The first neutralization tank is used to hold an alkaline solution, which is a sodium hydroxide solution or a saturated lime milk solution. The first water-cooling structure is disposed outside the first processing body to cool the first processing body.

2. The phosphorus recovery and treatment system according to claim 1, characterized in that, A first gate valve or a third gate valve is provided between the growth chamber and the cooling equipment; the cooling equipment is connected to a nitrogen delivery pipeline and an exhaust gas delivery pipeline respectively; the nitrogen delivery pipeline is used to deliver heated nitrogen; the exhaust gas delivery pipeline is connected to the main processing unit and is used to deliver phosphorus-containing gas to the main processing unit; the nitrogen delivery pipeline and the exhaust gas delivery pipeline are equipped with solenoid valves or manual valves, and the solenoid valves are communicatively connected to the controller.

3. The phosphorus recovery and treatment system according to claim 2, characterized in that, The cooling device is a cold trap, and a first gate valve is provided between the cold trap and the growth chamber; the cold trap is also connected to a molecular pump, and a second gate valve is provided between the cold trap and the molecular pump; the cold trap has a nitrogen purging port, an exhaust gas port, a liquid inlet port and a nitrogen purging port, the nitrogen purging port is connected to the nitrogen delivery pipeline, the exhaust gas port is connected to the exhaust gas delivery pipeline, the liquid inlet port is connected to the liquid nitrogen inlet pipe, and the nitrogen purging port is connected to the exhaust pipe.

4. The phosphorus recovery and treatment system according to claim 2, characterized in that, The cooling device is a cold pump, and the third gate valve is installed between the cold pump and the growth chamber. The cold pump is connected to the nitrogen delivery pipeline and the waste gas delivery pipeline through a three-way valve.

5. The phosphorus recovery and treatment system according to claim 3, characterized in that, The cold trap is equipped with at least one of a heating plate, a second thermocouple, and a vacuum gauge. The heating plate is configured to heat the cold trap after the growth chamber has been baked. The second thermocouple is used to measure the temperature inside the cold trap, and the vacuum gauge is used to measure the vacuum level inside the cold trap.

6. The phosphorus recovery and treatment system according to claim 1, characterized in that, The first processing body is provided with a first thermocouple, which is used to measure the temperature inside the first processing cavity, and / or, the first neutralization tank is provided with a turbidity sensor.

7. The phosphorus recovery and treatment system according to claim 1, characterized in that, The first processing chamber, the second processing chamber, the third processing chamber, the fourth processing chamber, and the first inspection chamber are all provided with conduits, and the bottom of the conduits is provided with a porous distributor, and / or, the first processing chamber, the second processing chamber, the third processing chamber, and the fourth processing chamber are all provided with baffles.

8. The phosphorus recovery and treatment system according to claim 1, characterized in that, The processing equipment also includes a backup processing device, which is detachably connected to the main processing device; the backup processing device includes a second water-cooling structure and a transparent second processing body; the second processing body includes a second neutralization tank and a backup first processing chamber, a backup second processing chamber, and a second inspection chamber connected in sequence; the backup first processing chamber is used to hold a copper sulfate solution; The spare second processing chamber is used to hold potassium permanganate solution; The second testing chamber is used to hold silver nitrate test paper and copper sulfate solution; the standby first processing chamber is used to receive phosphorus-containing gas discharged from the first testing chamber. The second neutralization tank is connectable to the backup first processing chamber, the backup second processing chamber, and the second inspection chamber. The second neutralization tank is used to hold an alkaline solution. The second water-cooling structure is disposed outside the second processing body to cool the second processing body.

9. The phosphorus recovery and treatment system according to claim 8, characterized in that, Each of the backup first processing chamber, the backup second processing chamber, and the second testing chamber is equipped with a backup conduit. The bottom of the backup conduit is equipped with a porous distributor, and / or, each of the backup first processing chamber and the backup second processing chamber is equipped with a backup baffle, and / or, the second neutralization tank is equipped with a turbidity sensor.

10. The phosphorus recovery and treatment system according to claim 1 or 8, characterized in that, Both the first processing body and the second processing body are made of acrylic sheet or quartz glass, and the surface of the acrylic sheet or quartz glass is covered with a polytetrafluoroethylene coating.

11. A recovery treatment method performed by the phosphorus recovery treatment system as described in any one of claims 1-10, characterized in that, Includes the following steps: S1. Connect the growth chamber and the cooling device, start the cooling device to make the pressure inside the cooling device lower than atmospheric pressure, and drive the phosphorus material in the growth chamber into the cooling device by baking. S2. Isolate the growth chamber and the cooling equipment, and introduce heated nitrogen into the cooling equipment to purge the phosphorus-containing gas inside the cooling equipment and discharge it to the outside. S3. The phosphorus-containing gas discharged from the cooling equipment is transported to the first processing body and sequentially undergoes cooling treatment, hydrogen peroxide treatment, copper sulfate treatment, potassium permanganate treatment and inspection treatment. The treated waste liquid is then discharged to the first neutralization tank for alkaline neutralization treatment.

12. The recovery treatment method performed by the phosphorus recovery treatment system according to claim 11, characterized in that, Step S1 further includes: opening the first gate valve or the third gate valve to connect the growth chamber and the cooling device, monitoring the content of white phosphorus in the growth chamber through a residual gas analyzer, and closing the first gate valve or the third gate valve in response to the content of white phosphorus in the growth chamber reaching a safe value. The first gate valve or the third gate valve is located between the growth chamber and the cooling device.

13. The recovery treatment method performed by the phosphorus recovery treatment system according to claim 12, characterized in that, Step S2 also includes: turning on the gas heater to heat nitrogen, delivering the heated nitrogen to the cooling device through the nitrogen delivery pipeline, and adjusting the flow rate of the heated nitrogen into the cooling device through the solenoid valve or manual valve on the nitrogen delivery pipeline. Step S3 further includes: transporting the phosphorus-containing gas discharged from the cooling equipment to the first processing body through an exhaust gas pipeline, and adjusting the flow rate of the phosphorus-containing gas entering the first processing body through a solenoid valve or a manual valve on the exhaust gas pipeline.

14. The recovery treatment method performed by the phosphorus recovery treatment system according to claim 13, characterized in that, The cooling device is a cold trap; In step S1, while opening the first gate valve, the second gate valve is also opened and the third gate valve is closed. The steps also include: introducing liquid nitrogen into the cold trap and controlling the vacuum level inside the cold trap by a molecular pump. The second gate valve is located between the cold trap and the molecular pump, and the third gate valve is located between the growth chamber and the cold pump. In step S2, closing the first gate valve and the second gate valve isolates the cold trap and the growth chamber. Heated nitrogen is then transported to the cold trap through the nitrogen delivery pipeline. The process further includes: controlling a solenoid valve on the nitrogen delivery pipeline via a controller, or using a manual valve on the nitrogen delivery pipeline, to adjust the flow rate of the heated nitrogen into the cold trap; heating the cold trap; and, in response to the heating temperature of the cold trap, controlling a solenoid valve on the waste gas delivery pipeline via the controller to adjust the flow rate of phosphorus-containing gas to the first processing unit. In step S3, the phosphorus-containing gas discharged from the cold trap is transported to the first processing body through the waste gas conveying pipe, and in response to the temperature in the first processing chamber, the flow rate of the phosphorus-containing gas entering the first processing body is adjusted by controlling the solenoid valve on the waste gas conveying pipe through the controller, or by adjusting the manual valve on the waste gas conveying pipe.

15. The recovery treatment method performed by the phosphorus recovery treatment system according to claim 13, characterized in that, The cooling device is a cold pump; in step S2, only the third gate valve is closed to isolate the cold pump and the growth chamber, and heated nitrogen is transported to the cold pump through a nitrogen delivery pipeline. The method also includes: adjusting the flow rate of heated nitrogen into the cold pump through a manual valve on the nitrogen delivery pipeline. In step S3, the phosphorus-containing gas discharged from the cold pump is transported to the first processing body through the waste gas conveying pipeline, and in response to the temperature in the first processing chamber and the reaction state in the four processing chambers, the flow rate of the phosphorus-containing gas entering the first processing body is adjusted by the manual valve on the waste gas conveying pipeline.

16. The recovery treatment method performed by the phosphorus recovery treatment system according to claim 11, characterized in that, The processing equipment also includes a backup processing device, which includes a second water-cooling structure and a transparent second processing body; the second processing body includes a second neutralization tank and a backup first processing chamber, a backup second processing chamber, and a second inspection chamber connected in sequence; the backup first processing chamber is used to hold copper sulfate solution; the backup second processing chamber is used to hold potassium permanganate solution. The second test chamber is used to hold silver nitrate test paper and copper sulfate solution; The second neutralization tank is connectable to the backup first processing chamber, the backup second processing chamber, and the second inspection chamber. The second neutralization tank is used to hold an alkaline solution. The second water-cooling structure is disposed outside the second processing body to cool the second processing body; The recycling method further includes the following steps: S4. In response to the reaction status in the four processing chambers of the first processing body and the reaction status in the first inspection chamber, determine whether to add a backup processing device. If the backup treatment device is added, the backup first treatment chamber is connected to the first inspection chamber through a pipeline to receive the phosphorus-containing gas discharged from the first inspection chamber, and then sequentially undergoes copper sulfate treatment, potassium permanganate treatment and inspection treatment. The treated waste liquid is then discharged to the second neutralization tank for alkaline neutralization treatment.

17. The recovery treatment method performed by the phosphorus recovery treatment system according to any one of claims 11-16, characterized in that, Also includes: The processing status of phosphorus recovery is determined by monitoring at least one of the following data: temperature, vacuum level, reaction status, color, and turbidity.

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