Method for recovering valuable metal from germanium-antimony-tellurium alloy waste

Abstract

The invention provides a method for recycling valuable metal from germanium-antimony-tellurium alloy waste. The method comprises the three steps of surface treatment, chlorine reaction and compartment condensation and discharging. Oxidation films on the surfaces of the waste materials are removed through surface treatment, and the subsequent chlorine reaction efficiency is improved; then a self-made chlorination-step condensation integrated device is utilized, germanium, antimony and tellurium react with chlorine at the high temperature to generate gaseous chloride, step-by-step condensation separation is achieved through partition temperature control based on the boiling point difference of tellurium tetrachloride, antimony pentachloride and germanium tetrachloride, and target products are collected respectively; and finally, introducing inert gas to purge residual chlorine, and discharging safely. The method has the advantages of short process flow, no need of complex wet process steps and low equipment investment; metal chlorides are efficiently separated through the integrated device, and recovery is thorough; and the pyrogenic process is mainly adopted, no wastewater is generated, only tail gas is treated in a compliance manner, and the method is environment-friendly. Compared with a traditional wet process, the method has the remarkable advantages of high efficiency, low cost, environment friendliness and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal material recycling, in particular to a method for recovering valuable metals from germanium-antimony-tellurium alloy waste. BACKGROUND

[0002] Germanium-antimony-tellurium alloy and its target material, such as Ge2Sb2Te5, Ge1Sb2Te4, etc., due to different components, can be represented as Ge x Sb y Te z , has unique physical and chemical properties and is widely used in many fields.

[0003] The preparation methods of germanium-antimony-tellurium alloy and its target material mainly include vacuum induction melting method, powder metallurgy method, two-step synthesis method and distillation-purification-melting method, etc. At present, the utilization rate of germanium-antimony-tellurium alloy and its target material preparation in scientific research and small-scale production, as well as the production and research and development of the end products, is not high. Part of the germanium-antimony-tellurium alloy and its target material will become waste in the process of synthesis and use, resulting in resource waste. The main components of germanium-antimony-tellurium alloy and its target material are Ge2Sb2Te5, Ge1Sb2Te4, etc. and other trace impurities. Germanium is a high-value rare metal and a strategy, and tellurium and antimony are also important metal resources, so the germanium, tellurium and antimony in this part of the waste must be fully recovered and utilized.

[0004] At present, there is only one kind of technology for recovering valuable metals from germanium-antimony-tellurium alloy waste at home and abroad. The germanium-antimony-tellurium waste target is sequentially coarsely crushed and pulverized to obtain a powder with an average particle size of 500-2000 μm; the powder is subjected to acid dissolution treatment to obtain a solution; a reducing agent is added to the solution and stirred, and then cooled and filtered to obtain filter residue A and filtrate; the filter residue A is washed with pure water and then dried to obtain crude tellurium; the filtrate is subjected to wet electrolysis to obtain crude antimony and electrolysis residual liquid; an alkaline compound is added to the electrolysis residual liquid to adjust the pH value to 8.5≤pH≤13, and then filtered to obtain filter residue B, which is washed with pure water and then dried to obtain crude germanium. This process mainly uses wet technology, and uses processes such as crushing, acid dissolution, reduction, electrolysis, etc. The disadvantages are that the process flow is too long, many types of equipment need to be invested, the cost is high, the efficiency is low, and the environmental protection pressure of wastewater is large, etc. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the prior art, and a method for recovering valuable metals from germanium-antimony-tellurium alloy waste is provided.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a method for recovering valuable metals from germanium-antimony-tellurium alloy waste, the specific steps are as follows: S1: surface treatment: put germanium antimony tellurium alloy waste into high-purity water and heat, and add ammonia and hydrogen peroxide for surface corrosion; after corrosion, take out the germanium antimony tellurium alloy waste and dry, and send the corrosion liquid to the germanium process to recover germanium.

[0007] By removing the oxide film and stains on the surface of germanium antimony tellurium alloy waste, the speed and efficiency of its subsequent reaction with chlorine gas are improved.

[0008] S2: chlorine reaction, step-by-step condensation; The dried germanium antimony tellurium alloy waste obtained in step S1 is loaded into the reaction chamber of the self-made "chlorination-step-by-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.

[0009] The reaction chamber is heated to make the germanium antimony tellurium alloy waste react with chlorine gas to generate germanium antimony tellurium chloride and be carried into the first collection chamber in gaseous form with excess chlorine gas stream; the appropriate temperature in the first collection chamber is controlled to allow tellurium tetrachloride vapor to cool and settle here; The antimony and germanium chlorides remain gaseous and enter the second collection chamber with the chlorine gas stream, and the appropriate temperature in the second collection chamber is controlled to allow tellurium tetrachloride vapor to cool and settle here; Finally, the chlorine gas stream continues to carry the germanium tetrachloride gas into the refrigeration system for rapid condensation, and then flows into the third collection chamber in liquid form, and the remaining excess chlorine gas enters the waste gas treatment system for compliance disposal.

[0010] By applying the self-made special "chlorination-step-by-step condensation integrated device", the germanium antimony tellurium alloy reacts with chlorine gas at high temperature to generate gaseous chlorides, and by taking advantage of the significant difference in boiling points of tellurium antimony germanium chlorides, the tellurium tetrachloride, antimony pentachloride and germanium tetrachloride gas are condensed in order of high to low boiling point and fully separated from each other, and are collected in the first collection chamber, the second collection chamber and the third collection chamber, respectively.

[0011] Germanium antimony tellurium alloy is represented as GexSbyTez, and its reaction equation with chlorine gas is shown in equation (1): 2Ge x Sb y Te z +(4x+5y+4z)Cl2=2xGeCl4+2ySbCl5+2zTeCl4 (1)。

[0012] S3: discharge; After the reaction chamber in step S2 has no obvious chlorination reaction, stop the chlorine gas, and blow out the residual chlorine gas in the device by introducing inert gas into the reaction chamber; at the same time, control the temperature of the integrated step-by-step condensation device, and after the overall temperature of the device is reduced to a safe temperature, take out different germanium antimony tellurium chlorides from the collection chambers respectively.

[0013] After the reaction chamber has no obvious chlorination reaction, stop heating the reaction chamber, stop the chlorine gas, and blow out the residual chlorine gas in the device by introducing inert gas into the device through the gas inlet for a period of time, and then stop the introduction of inert gas and close the gas inlet valve; stop the temperature control of the first collection chamber and the second collection chamber, and after the overall temperature of the device is reduced to a safe temperature, take out tellurium tetrachloride from the first collection chamber, which can be sold or further purified and sold; antimony pentachloride taken out of the second collection chamber can be sold or further purified and sold; germanium tetrachloride taken out of the third collection chamber can be sent to the germanium process to continue the production of germanium series products.

[0014] Under the condition of introducing inert gas, the residual chlorine gas in the device can be blown out, and the material can be discharged when the temperature in the device is less than or equal to 45℃, which can ensure the safety of use.

[0015] Preferably, in step S1, the high-purity water must completely soak 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.

[0016] Preferably, in step S2, the temperature of the reaction chamber is controlled at 500-650℃; the device has three collection chambers; the temperature in the first collection chamber is controlled at 260-300℃, and the temperature in the second collection chamber is controlled at 105-120℃; the temperature of the refrigeration system is controlled at -2--10℃.

[0017] Preferably, in step S3, the inert gas introduced is nitrogen or argon; the introduction time is 10-30min, and after the overall temperature of the device is not greater than 45℃, the collection chambers in the integrated step-by-step condensation device can be opened to take out tellurium tetrachloride, antimony pentachloride and germanium tetrachloride.

[0018] Preferably, the integrated step-by-step condensation device is provided with a reaction chamber, a first collection chamber, a second collection chamber, a refrigeration system, a third collection chamber, a gas inlet and a gas outlet; the reaction chamber is used to load germanium antimony tellurium alloy waste and react with chlorine gas; the first collection chamber is used for the settlement collection of tellurium tetrachloride; the second collection chamber is used for the settlement 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 gas inlet is used to introduce chlorine gas or inert gas; and the gas outlet is used to discharge reaction tail gas.

[0019] Preferably, the reaction chamber, the first collection chamber, the second collection chamber, the refrigeration system and the third collection chamber are sequentially connected by pipes; the gas inlet is arranged at the front end of the reaction chamber, and a gas inlet valve is arranged between the gas inlet and the reaction chamber; the gas outlet is arranged at the rear end of the third collection chamber, and a tail gas valve is arranged between the gas outlet and the third collection chamber.

[0020] Compared with the prior art, the method has the advantages that: the method adopts a process route of "surface treatment-chlorine reaction, chamber condensation-discharge", greatly simplifies complex steps such as crushing, acid dissolution and electrolysis in a traditional wet process, significantly shortens a process flow, reduces equipment investment and operation cost, and improves overall recovery efficiency.

[0021] Secondly, the method realizes step-by-step condensation and efficient separation of tellurium tetrachloride, antimony pentachloride and germanium tetrachloride in the same device by using the significant difference in boiling points of germanium chloride, antimony chloride and tellurium chloride, and high-purity target chlorides can be obtained without additional complex separation equipment, metal separation is complete, and resource recovery efficiency is high.

[0022] Finally, the method mainly adopts a pyrometallurgical process, no wastewater is generated in the process, only excess chlorine in tail gas is treated in compliance, the method is environmentally friendly and green, and the method greatly reduces the pressure of wastewater treatment and environmental protection risks brought by the traditional wet process. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a schematic diagram of a method of the present application; Figure 2 FIG. 2 is a distribution diagram of a step-by-step condensation integrated device used in the present application; In the figure: 1-reaction chamber; 2-first collection chamber; 3-second collection chamber; 4-refrigeration system; 5-third collection chamber; 6-gas inlet; 7-gas outlet; 8-gas inlet valve; 9-tail gas valve. DETAILED DESCRIPTION

[0024] In order to further understand the purpose, structure, features and functions of the present application, the following detailed description is provided in conjunction with the embodiments.

[0025] Please refer to Figure 1 and Figure 2 The present application provides a method for recovering valuable metals from germanium-antimony-tellurium alloy waste.

[0026] In the following examples, 1000g of the same batch of germanium-antimony-tellurium alloy was used as raw material, wherein the percentage content of germanium was 20.69%, the percentage content of antimony was 26.73%, and the percentage content of tellurium was 52.58%, i.e., the content of germanium was 206.9g, the content of antimony was 267.3g, and the content of tellurium was 525.8g.

[0027] Embodiment I: S1: Surface treatment: Put germanium-antimony-tellurium alloy waste into high-purity water and heat, and add ammonia water and hydrogen peroxide for surface corrosion; the added high-purity water must completely soak the germanium-antimony-tellurium alloy waste, the concentration of added ammonia water is 29%, the concentration of hydrogen peroxide is 30%, the volume ratio of ammonia water, hydrogen peroxide and high-purity water is 0.001:0.001:1, after corrosion, the germanium-antimony-tellurium alloy waste is taken out and dried, and the corrosion liquid is sent to the germanium process to recover germanium.

[0028] S2: Chlorination and fractional condensation: Put the dried germanium-antimony-tellurium alloy waste obtained in step S1 into the reaction chamber of the self-made "chlorination-fractional condensation integrated device", open the inlet valve and the tail gas valve, and pass chlorine into the device from the inlet. Heat the reaction chamber and control the temperature at 640-650℃, so that the germanium-antimony-tellurium alloy waste reacts with chlorine to generate germanium-antimony-tellurium chlorides and is carried into the first collection chamber in gaseous form with excess chlorine gas stream. Control the temperature in the first collection chamber at 290-300℃, let the tellurium tetrachloride vapor cool and settle here; the antimony and germanium chlorides remain gaseous and enter the second collection chamber with the chlorine gas stream, control the temperature in the second collection chamber at 115-120℃, let the tellurium tetrachloride vapor cool and settle here; finally, the chlorine gas stream continues to carry the 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℃, and the remaining excess chlorine gas enters the waste gas treatment system for disposal.

[0029] S3: Discharge: After the chlorination reaction is not obvious, stop heating the reaction chamber and stop passing chlorine, pass nitrogen into the device from the inlet for 30 minutes to blow out the residual chlorine in the equipment, then stop passing nitrogen and close the inlet valve; stop temperature control of the first collection chamber and the second collection chamber, and when the overall temperature of the device is not greater than 45℃, take tellurium tetrachloride from the first collection chamber, which can be sold or further purified and sold; take antimony pentachloride from the second collection chamber, which can be sold or further purified and sold; take germanium tetrachloride from the third collection chamber, which can be sent to the germanium process for further production of germanium series products.

[0030] The weight of the germanium tetrachloride obtained by the method of the embodiment is 609.32 g, the percentage content of germanium in the germanium tetrachloride is 33.82%, the metal amount of germanium is 206.07 g, and the direct yield of germanium is 99.6%; the weight of the antimony pentachloride obtained is 640.28 g, the percentage content of antimony in the antimony pentachloride is 40.62%, the metal amount of antimony is 260.08 g, and the direct yield of antimony is 97.3%; the weight of the tellurium tetrachloride obtained is 1108.88 g, the percentage content of tellurium in the tellurium tetrachloride is 45.9%, the metal amount of tellurium is 508.98 g, and the direct yield of tellurium is 96.8%.

[0031] Specific implementation two: S1: other conditions remain unchanged, the concentration of the added ammonia water is adjusted to 20%, the concentration of the added hydrogen peroxide is adjusted to 20%, and the volume ratio of the ammonia water, the hydrogen peroxide, and the high-purity water is adjusted to 0.003:0.003:1.

[0032] S2: other conditions remain unchanged, the reaction chamber is heated and the temperature control is adjusted to 500-510 ℃, the temperature in the first collection chamber is controlled to 260-270 ℃, the temperature in the second collection chamber is controlled to 105-110 ℃, and the temperature of the refrigeration system is controlled to -2--5 ℃.

[0033] S3: other conditions remain unchanged, and nitrogen gas is introduced into the device for 10 min from the gas inlet.

[0034] The weight of the germanium tetrachloride obtained by the method of the embodiment is 612.42 g, the percentage content of germanium in the germanium tetrachloride is 33.48%, the metal amount of germanium is 205.04 g, and the direct yield of germanium is 99.1%; the weight of the antimony pentachloride obtained is 651.82 g, the percentage content of antimony in the antimony pentachloride is 40.27%, the metal amount of antimony is 262.49 g, and the direct yield of antimony is 98.2%; the weight of the tellurium tetrachloride obtained is 1114.33 g, the percentage content of tellurium in the tellurium tetrachloride is 46.1%, the metal amount of tellurium is 513.71 g, and the direct yield of tellurium is 97.7%.

[0035] Specific implementation three: S1: other conditions remain unchanged, the concentration of the added ammonia water is adjusted to 25%, the concentration of the added hydrogen peroxide is adjusted to 25%, and the volume ratio of the ammonia water, the hydrogen peroxide, and the high-purity water is adjusted to 0.002:0.002:1.

[0036] S2: other conditions remain unchanged, the reaction chamber is heated and the temperature control is adjusted to 600-610 ℃, the temperature in the first collection chamber is controlled to 280-290 ℃, the temperature in the second collection chamber is controlled to 110-115 ℃, and the temperature of the refrigeration system is controlled to -5--8 ℃.

[0037] S3: With other conditions unchanged, nitrogen is introduced into the device from the air inlet for 20 minutes.

[0038] Using the method of this embodiment, the weight of the obtained germanium tetrachloride is 612.01g, the percentage of germanium in the germanium tetrachloride is 33.57%, the metal amount of germanium is 205.45g, and the final direct yield of germanium is 99.3%; the weight of the obtained antimony pentachloride is 648.52g, the percentage of antimony in antimony pentachloride is 40.31%, the metal amount of antimony is 261.42g, and the direct yield of antimony is 97.8%; the weight of the obtained tellurium tetrachloride is 1103.84g, the percentage of tellurium in tellurium tetrachloride is 46.3%, the metal amount of tellurium is 511.08g, and the direct yield of tellurium is 97.2%.

[0039] The three examples demonstrate the remarkable effectiveness of the present method for recovering valuable metals from Germanium-Antimony-Tellurium alloy scrap. Efficient recovery of valuable metals was achieved under varying surface treatment parameters (varying concentrations and ratios of ammonia and hydrogen peroxide), chlorination reaction temperature (adjustable between 500 and 650°C), and inert gas purge time during discharge (10 to 30 minutes). Direct recovery rates for germanium ranged from 99.1% to 99.6%, for antimony from 97.3% to 98.2%, and for tellurium from 96.8% to 97.7%, all achieving high levels. This demonstrates the stability and reliability of the process, effectively recovering valuable metals from Germanium-Antimony-Tellurium alloy scrap, and demonstrates promising industrial application prospects.

[0040] The present invention has been described with reference to the above embodiments. However, the above embodiments are merely exemplary embodiments of the present invention. It should be noted that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and improvements that do not depart from the spirit and scope of the present invention are intended to be protected by the present invention.

Claims

1. A method for recovering valuable metals from germanium-antimony-tellurium alloy scrap, characterized by: The specific steps of the method are as follows: S1: surface treatment; The scrap of germanium antimony tellurium alloy is placed in high-purity water and heated, and ammonia and hydrogen peroxide are added to perform surface corrosion; after corrosion, the scrap of germanium antimony tellurium alloy is removed and dried, and the corrosion liquid is sent to the germanium process to recover germanium; S2: Chlorine reaction, condensation in separate chambers; The germanium antimony tellurium alloy scrap dried in step S1 is loaded into a reaction chamber in a self-made "chlorination-stepwise condensation integrated device", and chlorine gas is introduced and then heated to generate germanium antimony tellurium chloride. By controlling different temperatures in different areas of the device, the germanium antimony tellurium chlorides are condensed in descending order of boiling point and fully separated from each other, and are collected in different collection chambers of the stepwise condensation integrated device. Excess chlorine gas enters the exhaust gas treatment system through the exhaust outlet of the stepwise condensation integrated device for legal disposal; S3: discharging; After no obvious chlorination reaction occurs in the reaction chamber in step S2, the introduction of chlorine gas is stopped, and an inert gas is introduced into the reaction chamber to blow out the residual chlorine in the equipment; at the same time, the temperature of the step-by-step condensation integrated device is controlled, and after the overall temperature of the device drops to a safe temperature, different chlorides of germanium, antimony and tellurium are taken out from the collection chamber respectively.

2. The method for recovering valuable metals from germanium-antimony-tellurium alloy scrap according to claim 1, wherein: In step S1, the high-purity water must completely infiltrate the germanium antimony tellurium alloy scrap, the concentration of the added ammonia water is 20-29%, the concentration of the hydrogen peroxide is 20-30%, and the volume ratio of the 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 scrap according to claim 1, wherein: In step S2, the temperature of the reaction chamber is controlled at 500-650°C; three collection chambers are provided in the device; the temperature in the first collection chamber is controlled at 260-300°C, and the temperature in the second collection chamber is controlled at 105-120°C; the temperature of the refrigeration system is controlled at -2--10°C.

4. The method for recovering valuable metals from germanium-antimony-tellurium alloy scrap according to claim 1, wherein: 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 is no more than 45°C, the collection chamber in the step-by-step condensation integrated device can be opened to take out tellurium tetrachloride, antimony pentachloride and germanium tetrachloride.

5. The method for recovering valuable metals from germanium-antimony-tellurium alloy scrap according to claim 1, wherein: The step-by-step condensation integrated device is equipped with a reaction chamber, a first collection chamber, a second collection chamber, a refrigeration system, a third collection chamber, an air inlet and an exhaust port; the reaction chamber is used to load germanium antimony tellurium alloy scrap and react with chlorine; the first collection chamber is used to settle and collect tellurium tetrachloride; the second collection chamber is used to settle and collect 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 or inert gas; and the exhaust port is used to discharge reaction tail gas.

6. The method for recovering valuable metals from germanium-antimony-tellurium alloy scrap according to claim 5, wherein: The reaction chamber, the first collection chamber, the second collection chamber, the refrigeration system, and the third collection chamber are connected in sequence through pipelines; the air inlet is arranged at the front end of the reaction chamber, and an air inlet valve is also provided between the two; the exhaust port is arranged at the rear end of the third collection chamber, and an exhaust valve is also provided between the two.

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