A method for recovering valuable metals from germanium-antimony-tellurium alloy waste

Abstract

This invention provides a method for recovering valuable metals from germanium-antimony-tellurium alloy waste, comprising three steps: surface treatment, chlorine reaction and compartment condensation, and discharge. Surface treatment removes the oxide film from the waste surface, improving the efficiency of the subsequent chlorine reaction. A self-made integrated chlorination-step condensation device is then used to react germanium-antimony-tellurium with chlorine at high temperature to generate gaseous chlorides. Based on the boiling point differences of tellurium tetrachloride, antimony pentachloride, and germanium tetrachloride, step-by-step condensation and separation are achieved through compartment temperature control, and the target products are collected separately. Finally, inert gas is introduced to purge residual chlorine, and the material is safely discharged. This invention features a short process flow, eliminates the need for complex wet processing steps, and requires low equipment investment. The integrated device efficiently separates metal chlorides, ensuring thorough recovery. Furthermore, it primarily uses pyrometallurgical methods, generating no wastewater and only requiring compliant tail gas treatment, making it environmentally friendly. Compared to traditional wet processes, it offers significant advantages such as high efficiency, low cost, and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of metal material recycling, specifically to a method for recovering valuable metals from germanium-antimony-tellurium alloy waste. Background Technology

[0002] Germanium-antimony-tellurium alloys and their targets, such as Ge2Sb2Te5 and Ge1Sb2Te4, vary in composition and can be used to target specific materials. x Sb y Te z It is indicated that it has unique physicochemical properties and has wide applications in many fields.

[0003] The main methods for preparing germanium-antimony-tellurium alloys and their targets include vacuum induction melting, powder metallurgy, two-step synthesis, and distillation purification-melting. Currently, the utilization rate of germanium-antimony-tellurium alloys and their targets, as well as the production and R&D of downstream products, in research and small-scale production is low. Some germanium-antimony-tellurium alloys and their targets become waste during synthesis and use, leading to resource waste. The main components of germanium-antimony-tellurium alloys and their targets are Ge2Sb2Te5, Ge1Sb2Te4, and other trace impurities. Germanium is a high-value rare and dispersed metal and a strategic resource, while tellurium and antimony are also important metal resources. Therefore, the germanium, tellurium, and antimony in this waste must be fully recycled and utilized.

[0004] Currently, only one technology for recovering valuable metals from germanium-antimony-tellurium alloy waste has been reported both domestically and internationally. The process involves sequentially crushing and pulverizing the germanium-antimony-tellurium waste target to obtain powder with an average particle size of 500-2000 μm; acid dissolving the powder to obtain a solution; adding a reducing agent to the solution and stirring, followed by cooling and filtration to obtain filter residue A and filtrate; washing filter residue A with pure water and drying to obtain crude tellurium; performing wet electrolysis on the filtrate to obtain crude antimony and residual electrolyte; adding an alkaline compound to the residual electrolyte to adjust the pH to 8.5 ≤ pH ≤ 13, followed by filtration to obtain filter residue B; washing filter residue B with pure water and drying to obtain crude germanium. This process mainly employs wet technology, involving crushing, acid dissolving, reduction, and electrolysis. Its disadvantages include a long process flow, the need for various types of equipment, high cost, low efficiency, and significant environmental impact due to wastewater. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for recovering valuable metals from germanium-antimony-tellurium alloy waste.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for recovering valuable metals from germanium-antimony-tellurium alloy waste, the specific steps of which are as follows:

[0007] S1: Surface treatment: The germanium-antimony-tellurium alloy waste is heated in high-purity water, and ammonia and hydrogen peroxide are added for surface corrosion; after corrosion, the germanium-antimony-tellurium alloy waste is taken out and dried, and the corrosion solution is sent to the germanium process to recover germanium.

[0008] By removing the oxide film and stains from the surface of germanium-antimony-tellurium alloy waste, the speed and efficiency of its subsequent reaction with chlorine gas can be improved.

[0009] S2: Chlorine gas reacts and condenses in separate compartments;

[0010] The dried germanium-antimony-tellurium alloy waste obtained in step S1 is loaded into the reaction chamber of the self-made "chlorination-step condensation integrated device". The inlet valve and the tail gas valve are opened, and chlorine gas is introduced into the device from the inlet.

[0011] The reaction chamber is heated to react the germanium-antimony-tellurium alloy waste with chlorine gas, generating germanium-antimony-tellurium chloride, which is carried into the first collection chamber in gaseous form along with the excess chlorine gas flow. The temperature in the first collection chamber is controlled appropriately to allow the tellurium tetrachloride vapor to cool down and settle.

[0012] Antimony and germanium chlorides remain in a gaseous state and enter the second collection chamber along with the chlorine gas flow. The appropriate temperature in the second collection chamber is controlled to allow the tellurium tetrachloride vapor to cool down and settle.

[0013] Finally, the chlorine gas stream continues to carry germanium tetrachloride gas into the refrigeration system, where it is rapidly condensed and flows into the third collection chamber in liquid form. The remaining excess chlorine gas enters the waste gas treatment system from the exhaust port for compliant disposal.

[0014] By using a self-made dedicated "chlorination-step condensation integrated device", germanium-antimony-tellurium alloy and chlorine gas react at high temperature to generate gaseous chlorides. Taking advantage of the significant difference in boiling points among the chlorides of tellurium, antimony, and germanium, different temperatures are controlled in different areas to allow tellurium tetrachloride, antimony pentachloride, and germanium tetrachloride gases to be condensed sequentially in order of decreasing boiling point and fully separated from each other. The gases are then collected in the first, second, and third collection chambers, respectively.

[0015] The germanium-antimony-tellurium alloy is represented by GexSbyTez, and its reaction equation with chlorine is shown in formula (1):

[0016] 2Ge x Sb y Te z +(4x+5y+4z)Cl2=2xGeCl4+2ySbCl5+2zTeCl4 (1).

[0017] S3: Discharge;

[0018] After the chlorination reaction in the reaction chamber in step S2 is no longer obvious, stop the chlorine gas supply and introduce inert gas into the reaction chamber to blow out the residual chlorine gas in the equipment; at the same time, control the temperature of the stepwise condensation integrated device, and after the overall temperature of the device drops to a safe temperature, take out different germanium, antimony and tellurium chlorides from the collection chamber respectively.

[0019] After the chlorination reaction is no longer obvious, stop heating the reaction chamber and stop the chlorine gas supply. Inert gas is introduced into the device through the inlet for a period of time to blow out the residual chlorine gas in the equipment. Then, stop the inert gas supply and close the inlet valve. Stop temperature control of the first and second collection chambers. After the overall temperature of the device drops to a safe temperature, obtain tellurium tetrachloride from the first collection chamber. It can be sold or further purified before sale. Antimony pentachloride obtained from the second collection chamber can be sold or further purified before sale. Germanium tetrachloride obtained from the third collection chamber can be sent to the germanium process to continue the production of germanium series products.

[0020] When an inert gas is introduced, residual chlorine gas in the equipment can be blown out, and the material is discharged when the temperature inside the device is less than or equal to 45°C, which ensures the safety of use.

[0021] Preferably, in step S1, the high-purity water must completely wet the germanium-antimony-tellurium alloy waste, the concentration of ammonia water is 20-29%, the concentration of hydrogen peroxide is 20-30%, and the volume ratio of ammonia water, hydrogen peroxide and high-purity water is 0.001-0.003: 0.001-0.003:1.

[0022] Preferably, in step S2, the temperature of the reaction chamber is controlled at 500-650°C; the office is equipped with three collection chambers; the temperature in the first collection chamber is controlled at 260-300°C, the temperature in the second collection chamber is controlled at 105-120°C; and the temperature of the refrigeration system is controlled at -2 to -10°C.

[0023] Preferably, in step S3, the inert gas introduced is nitrogen or argon; the introduction time is 10 to 30 minutes, and after the overall temperature of the device does not exceed 45°C, the collection chamber in the stepwise condensation integrated device can be opened to remove tellurium tetrachloride, antimony pentachloride and germanium tetrachloride.

[0024] Preferably, the stepwise condensation integrated device includes a reaction chamber, a first collection chamber, a second collection chamber, a refrigeration system, a third collection chamber, an air inlet, and an exhaust outlet; the reaction chamber is used to load germanium-antimony-tellurium alloy waste and react it with chlorine gas; the first collection chamber is used for the sedimentation collection of tellurium tetrachloride; the second collection chamber is used for the sedimentation collection of antimony pentachloride; the refrigeration system is used to condense germanium tetrachloride gas into liquid; the third collection chamber is used to collect liquid germanium tetrachloride; the air inlet is used to introduce chlorine gas or inert gas; and the exhaust outlet is used to discharge reaction tail gas.

[0025] Preferably, the reaction chamber, the first collection chamber, the second collection chamber, the refrigeration system, and the third collection chamber are connected in sequence by pipelines; the air inlet is located at the front end of the reaction chamber, and an air inlet valve is provided between them; the exhaust port is located at the rear end of the third collection chamber, and an exhaust valve is provided between them.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adopts the process route of "surface treatment - chlorine reaction, compartment condensation - discharge", which greatly simplifies the complex crushing, acid dissolution, electrolysis and other steps in the traditional wet process, significantly shortens the process flow, reduces equipment investment and operating costs, and improves the overall recovery efficiency.

[0027] Secondly, this invention utilizes a self-made "chlorination-stepwise condensation integrated device" to achieve stepwise condensation and efficient separation of tellurium tetrachloride, antimony pentachloride, and germanium tetrachloride within the same device by taking advantage of the significant differences in the boiling points of germanium, antimony, and tellurium chlorides. High-purity target chlorides can be obtained without additional complex separation equipment, resulting in thorough metal separation and high resource recovery efficiency.

[0028] Finally, this invention primarily employs a pyrometallurgical process, which generates no wastewater and only treats excess chlorine in the exhaust gas in compliance with regulations. It is environmentally friendly and green, significantly reducing the wastewater treatment pressure and environmental risks associated with traditional wet processes. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0030] Figure 2 This is a schematic diagram showing the distribution of the step-by-step condensation integrated device used in this invention;

[0031] In the diagram: 1-Reaction chamber; 2-First collection chamber; 3-Second collection chamber; 4-Refrigeration system; 5-Third collection chamber; 6-Air inlet; 7-Exhaust outlet; 8-Air inlet valve; 9-Exhaust valve. Detailed Implementation

[0032] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0033] Please refer to the reference. Figure 1 as well as Figure 2 This invention provides a method for recovering valuable metals from germanium-antimony-tellurium alloy waste.

[0034] In the following examples, 1000g of the same batch of germanium-antimony-tellurium alloy was used as raw material each time, wherein the percentage content of germanium was 20.69%, antimony was 26.73%, and tellurium was 52.58%, that is, the germanium content was 206.9g, the antimony content was 267.3g, and the tellurium content was 525.8g.

[0035] Specific Implementation 1:

[0036] S1: Surface treatment: The germanium-antimony-tellurium alloy waste is heated in high-purity water, and ammonia and hydrogen peroxide are added for surface etching. The high-purity water must completely wet the germanium-antimony-tellurium alloy waste. The concentration of ammonia is 29% and the concentration of hydrogen peroxide is 30%. The volume ratio of ammonia, hydrogen peroxide and high-purity water is 0.001:0.001:1. After etching, the germanium-antimony-tellurium alloy waste is taken out and dried. The etching solution is sent to the germanium process to recover germanium.

[0037] S2: Chlorination and stepwise condensation:

[0038] The dried germanium-antimony-tellurium alloy waste obtained in step S1 is loaded into the reaction chamber of the self-made "chlorination-step condensation integrated device". The inlet valve and the tail gas valve are opened, and chlorine gas is introduced into the device from the inlet. The reaction chamber is heated and the temperature is controlled at 640-650℃ to react the germanium-antimony-tellurium alloy waste with chlorine gas to generate germanium-antimony-tellurium chloride, which is carried in gaseous form by the excess chlorine gas flow into the first collection chamber. The temperature in the first collection chamber is controlled at 290-300℃ to allow tellurium tetrachloride vapor to cool down and settle. The antimony and germanium chloride remain in gaseous form and enter the second collection chamber with the chlorine gas flow. The temperature in the second collection chamber is controlled at 115-120℃ to allow tellurium tetrachloride vapor to cool down and settle. Finally, the chlorine gas flow continues to carry germanium tetrachloride gas into the refrigeration system for rapid condensation, and then flows into the third collection chamber in liquid form. The temperature of the refrigeration system is controlled at -7 to -10℃. The remaining excess chlorine gas enters the waste gas treatment system from the tail gas outlet for compliant disposal.

[0039] S3: Discharge:

[0040] After the chlorination reaction is no longer obvious, stop heating the reaction chamber and stop the chlorine gas supply. Then, introduce nitrogen gas into the device through the gas inlet for 30 minutes to purge the residual chlorine gas in the equipment. After that, stop the nitrogen gas supply and close the gas inlet valve. Stop temperature control of the first and second collection chambers. After the overall temperature of the device does not exceed 45°C, obtain tellurium tetrachloride from the first collection chamber. It can be sold or further purified before sale. Antimony pentachloride obtained from the second collection chamber can be sold or further purified before sale. Germanium tetrachloride obtained from the third collection chamber can be sent to the germanium process to continue the production of germanium series products.

[0041] Using the method of this embodiment, the weight of germanium tetrachloride obtained was 609.32 g, the percentage of germanium in germanium tetrachloride was 33.82%, the metal content of germanium was 206.07 g, and the final direct recovery rate of germanium was 99.6%; the weight of antimony pentachloride obtained was 640.28 g, the percentage of antimony in antimony pentachloride was 40.62%, the metal content of antimony was 260.08 g, and the direct recovery rate of antimony was 97.3%; the weight of tellurium tetrachloride obtained was 1108.88 g, the percentage of tellurium in tellurium tetrachloride was 45.9%, the metal content of tellurium was 508.98 g, and the direct recovery rate of tellurium was 96.8%.

[0042] Implementation 2:

[0043] S1: With other conditions unchanged, add ammonia water concentration to 20%, hydrogen peroxide concentration to 20%, and adjust the volume ratio of ammonia water, hydrogen peroxide and high-purity water to 0.003:0.003:1.

[0044] S2: With other conditions unchanged, heat the reaction chamber and adjust the temperature to 500-510℃; adjust the temperature in the first collection chamber to 260-270℃, and adjust the temperature in the second collection chamber to 105-110℃; control the temperature of the freezing system to -2 to -5℃.

[0045] S3: With other conditions unchanged, adjust to allow nitrogen to flow into the device from the air inlet for 10 minutes.

[0046] Using the method of this embodiment, the weight of germanium tetrachloride obtained was 612.42 g, the percentage of germanium in germanium tetrachloride was 33.48%, the metal content of germanium was 205.04 g, and the final direct recovery rate of germanium was 99.1%; the weight of antimony pentachloride obtained was 651.82 g, the percentage of antimony in antimony pentachloride was 40.27%, the metal content of antimony was 262.49 g, and the direct recovery rate of antimony was 98.2%; the weight of tellurium tetrachloride obtained was 1114.33 g, the percentage of tellurium in tellurium tetrachloride was 46.1%, the metal content of tellurium was 513.71 g, and the direct recovery rate of tellurium was 97.7%.

[0047] Specific Implementation Three:

[0048] S1: With other conditions unchanged, add ammonia water concentration to 25%, hydrogen peroxide concentration to 25%, and adjust the volume ratio of ammonia water, hydrogen peroxide and high-purity water to 0.002:0.002:1.

[0049] S2: With other conditions unchanged, heat the reaction chamber and adjust the temperature to 600-610℃; adjust the temperature in the first collection chamber to 280-290℃, and adjust the temperature in the second collection chamber to 110-115℃; control the temperature of the freezing system to -5--8℃.

[0050] S3: With other conditions unchanged, adjust to allow nitrogen to flow into the device from the air inlet for 20 minutes.

[0051] Using the method of this embodiment, the weight of germanium tetrachloride obtained was 612.01 g, the percentage of germanium in germanium tetrachloride was 33.57%, the metal content of germanium was 205.45 g, and the final direct recovery rate of germanium was 99.3%; the weight of antimony pentachloride obtained was 648.52 g, the percentage of antimony in antimony pentachloride was 40.31%, the metal content of antimony was 261.42 g, and the direct recovery rate of antimony was 97.8%; the weight of tellurium tetrachloride obtained was 1103.84 g, the percentage of tellurium in tellurium tetrachloride was 46.3%, the metal content of tellurium was 511.08 g, and the direct recovery rate of tellurium was 97.2%.

[0052] The three embodiments demonstrate that the method for recovering valuable metals from germanium-antimony-tellurium alloy waste of the present invention is highly effective. High-efficiency recovery of valuable metals can be achieved under various surface treatment parameters (different concentrations and ratios of ammonia and hydrogen peroxide), chlorination reaction temperatures (adjusted within the range of 500-650℃), and inert gas purging time during discharge (10-30 min). Specifically, the direct recovery rates of germanium, antimony, and tellurium are between 99.1% and 99.6%, 97.3% and 98.2%, and 96.8% and 97.7%, respectively, all reaching high levels. This fully demonstrates the stability and reliability of the method, effectively recovering valuable metals from germanium-antimony-tellurium alloy waste, and possesses promising prospects for industrial application.

[0053] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A method for recovering valuable metals from germanium-antimony-tellurium alloy waste, characterized in that: The specific steps of the method are as follows: S1: Surface treatment; Germanium-antimony-tellurium alloy waste is heated in high-purity water, and ammonia and hydrogen peroxide are added for surface corrosion. After corrosion, the waste is removed, dried, and the corrosion solution is sent to the germanium process for germanium recovery. S2: Chlorine gas reacts and condenses in separate compartments; The dried germanium-antimony-tellurium alloy waste from step S1 is loaded into the reaction chamber of a self-made "chlorination-stepwise condensation integrated device". Chlorine gas is introduced and heated to generate germanium-antimony-tellurium chlorides. By controlling different temperatures in different areas of the device, the germanium-antimony-tellurium chlorides are condensed sequentially in order of decreasing boiling point, allowing for thorough separation. The chlorides are collected in different collection chambers within the stepwise condensation integrated device. Excess chlorine gas is discharged into the waste gas treatment system through the exhaust port of the stepwise condensation integrated device for compliant disposal. The temperature of the reaction chamber is controlled at 500–650°C. The device has three collection chambers: the temperature in the first collection chamber is controlled at 260–300°C, the temperature in the second collection chamber is controlled at 105–120°C, and the temperature of the refrigeration system is controlled at -2 to -10°C. S3: Discharge; After the chlorination reaction in the reaction chamber in step S2 is no longer obvious, stop the chlorine gas supply and introduce inert gas into the reaction chamber to blow out the residual chlorine gas in the equipment; at the same time, control the temperature of the stepwise condensation integrated device, and after the overall temperature of the device drops to a safe temperature, take out different germanium, antimony and tellurium chlorides from the collection chamber respectively.

2. The method for recovering valuable metals from germanium-antimony-tellurium alloy waste as described in claim 1, characterized in that: In step S1, the high-purity water must completely immerse the germanium-antimony-tellurium alloy waste. The concentration of ammonia water is 20-29%, the concentration of hydrogen peroxide is 20-30%, and the volume ratio of ammonia water, hydrogen peroxide, and high-purity water is 0.001-0.003: 0.001-0.003:

1.

3. The method for recovering valuable metals from germanium-antimony-tellurium alloy waste as described in claim 1, characterized in that: In step S3, the inert gas introduced is nitrogen or argon; the introduction time is 10 to 30 minutes. After the overall temperature of the device does not exceed 45°C, the collection chamber in the stepwise condensation integrated device can be opened to remove tellurium tetrachloride, antimony pentachloride and germanium tetrachloride.

4. The method for recovering valuable metals from germanium-antimony-tellurium alloy waste as described in claim 1, characterized in that: The stepwise condensation integrated device includes a reaction chamber, a first collection chamber, a second collection chamber, a refrigeration system, a third collection chamber, an air inlet, and an exhaust outlet. The reaction chamber is used to load germanium-antimony-tellurium alloy waste and react it with chlorine gas. The first collection chamber is used for the sedimentation and collection of tellurium tetrachloride. The second collection chamber is used for the sedimentation and collection of antimony pentachloride. The refrigeration system is used to condense germanium tetrachloride gas into liquid. The third collection chamber is used to collect liquid germanium tetrachloride. The air inlet is used to introduce chlorine gas or inert gas. The exhaust outlet is used to discharge reaction tail gas.

5. The method for recovering valuable metals from germanium-antimony-tellurium alloy waste as described in claim 4, characterized in that: The reaction chamber, the first collection chamber, the second collection chamber, the refrigeration system, and the third collection chamber are connected in sequence by pipelines; the air inlet is located at the front end of the reaction chamber, and an air inlet valve is provided between them; the exhaust port is located at the rear end of the third collection chamber, and an exhaust valve is provided between them.

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