A process for recovering germanium from germanium-silicon alloy scrap

Abstract

The application discloses a process for recovering germanium from germanium-silicon alloy waste, and belongs to the technical field of germanium recovery, which comprises the following steps: S1. oxidizing and roasting germanium-silicon alloy waste to obtain roasting clinker; S2. sulfidizing and fixing the roasting clinker and pyrite to obtain activated clinker; S3. after the activated clinker is leached by a sulfuric acid leaching solution, solid-liquid separation is performed, and a germanium-containing leaching solution is collected; S4. a multistage countercurrent extraction is performed on the germanium-containing leaching solution by using an amine extractant to obtain a loaded organic phase; the loaded organic phase is back-extracted by using an alkaline back-extracting solution to obtain a germanate solution; and S5. germanium dioxide pure product is obtained by hydrolysis and precipitation of the germanate solution. The roasting process of the application fixes impurities and activates germanium into germanium dioxide which can be dissolved, the purification stage can efficiently separate germanium and other impurity ions, and finally, hydrolysis and precipitation control product consistency. The recovery process of the application has high recovery efficiency and purity, is more environmentally friendly, and is expected to realize large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of germanium recycling technology, specifically a process for recovering germanium from germanium-silicon alloy waste. Background Technology

[0002] Germanium, as a rare and precious metal, possesses excellent semiconductor properties, infrared transmittance, and carrier mobility, and is widely used in infrared optics, laser devices, semiconductor chips, and photovoltaic cells. Especially in high-frequency germanium-silicon transistors and infrared lenses, germanium-silicon alloys are the core substrate material. With the large-scale production and replacement of these devices, a large amount of germanium-silicon alloy waste is generated, including lens blanks from infrared optics and laser devices, germanium-silicon alloy substrates, wafer fragments, high-frequency germanium-silicon transistor processing scraps, chip manufacturing scraps, germanium-silicon epitaxial wafer residues, and photovoltaic cell silicon wafer cutting waste. The germanium content in these wastes varies considerably. Photovoltaic cell silicon wafer cutting waste exhibits a wide range of Ge content fluctuations, infrared optics and laser device waste has a lower total impurity content, while high-frequency germanium-silicon transistor processing waste has a relatively stable composition, making it a raw material with significant recycling value.

[0003] Currently, the main processes for recovering germanium from germanium-silicon alloy waste include roasting, leaching, extraction, and precipitation. Existing processes mostly employ single oxidation or reduction roasting, which only achieves simple phase transformation of germanium and cannot specifically fix impurities. For high-frequency germanium-silicon transistor waste containing impurities such as Fe and Cu, the impurities remain in oxide form after single roasting, dissolving simultaneously with germanium during subsequent leaching, significantly increasing separation difficulty. Some processes use high-temperature roasting to improve germanium conversion efficiency, but this easily leads to the reduction of GeO2 to elemental germanium, reducing the leaching rate. Furthermore, high temperatures exacerbate the interaction between impurities and germanium, further affecting separation. In the extraction stage, existing leaching processes mostly use single sulfuric acid or hydrochloric acid leaching; single acid leaching cannot effectively complex GeO2. 4+ This process easily leads to germanium loss through hydrolysis and precipitation; it also fails to mask residual impurity ions and struggles to address insufficient penetration at the solid-liquid interface, resulting in leaching rates typically only 65-75%. Furthermore, for infrared optical device waste with low impurity content, the excessively vigorous leaching system causes secondary pollution from silicon slag, making recycling impossible. During the purification stage, the extraction and back-extraction processes exhibit poor selectivity, easily leading to emulsification and germanium loss; insufficient precision in hydrolysis and precipitation makes it difficult to achieve the required product purity. Summary of the Invention

[0004] To overcome the aforementioned technical problems, this invention provides a process for recovering germanium from germanium-silicon alloy waste. The calcination process of this invention fixes impurities and activates elemental germanium into soluble germanium dioxide. The purification stage efficiently separates germanium from other impurity ions, and finally, hydrolysis precipitation controls the consistency of the pure product. This recovery process offers high recovery efficiency and purity, is more environmentally friendly, and holds promise for large-scale production.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] This invention discloses a process for recovering germanium from germanium-silicon alloy waste, comprising the following steps: S1. Oxidize and roast the germanium-silicon alloy waste to obtain roasted clinker; S2. Activated clinker is obtained by fixing roasted clinker and pyrite by sulfidation. S3. After leaching the activated clinker with sulfuric acid, solid-liquid separation is performed, and the germanium-containing leachate is collected. S4. The germanium-containing leachate is subjected to multi-stage countercurrent extraction using an amine extractant to obtain a loaded organic phase; then the loaded organic phase is back-extracted using an alkaline back-extraction solution to obtain a germanate solution; S5. Germanate solution was hydrolyzed and precipitated to obtain pure germanium dioxide.

[0007] The germanium-silicon alloy waste contains the following chemical elements by mass percentage: 5-8% Ge, 3.0-5.5% Fe, 1.0-2.0% Cu, 0.3-1.0% Al, 0.2-0.6% Zn, 0.5-1.5% C, other impurity elements <5%, and the balance silicon; preferably, the germanium-silicon alloy waste contains the following chemical elements by mass percentage: 6.5-7.0% Ge, 4.0-4.5% Fe, 1.4-1.6% Cu, 0.6-0.8% Al, 0.3-0.5% Zn, 0.9-1.1% C, 2.0-4.5% other impurity elements, and the balance silicon.

[0008] The germanium-silicon alloy waste originates from infrared optical and laser device waste, semiconductor device manufacturing waste, or photovoltaic device processing waste; particularly at least one of the following: germanium-silicon alloy substrate, lens blank, wafer fragments, high-frequency germanium-silicon transistor processing scraps and cutting debris, semiconductor chip manufacturing scraps, germanium-silicon epitaxial wafer production residues, and photovoltaic cell silicon wafer cutting waste.

[0009] S1 also includes a pretreatment process for the germanium-silicon alloy waste, wherein the pretreatment involves crushing and grinding the germanium-silicon alloy waste to 80-200 mesh. In S1, the oxidative calcination is carried out in an oxidizing atmosphere at 520~620℃ for 1~3 hours; preferably, the oxidative calcination is carried out in an oxidizing atmosphere at 550~600℃ for 1.5~2.5 hours. The oxidizing atmosphere is air or oxygen.

[0010] In S2, the vulcanization fixation is carried out by calcination at 500~550℃ for 1~1.5h under an inert atmosphere. In S2, the amount of pyrite added is 3-8% of the mass of the roasted clinker, preferably 4-6%.

[0011] In S3, the pH of the sulfuric acid leachate is 1.0~2.0, preferably 1.2~1.8; Further, the sulfuric acid leachate contains 1.0~4.0 wt% citric acid, 1.0~3.0 wt% oxalic acid, 0.2~1.5 wt% ascorbic acid and 0.02~0.10 wt% fatty alcohol polyoxyethylene ether; preferably, the sulfuric acid leachate contains 1.5~3 wt% citric acid, 1.0~3.0 wt% oxalic acid, 0.2~1.0 wt% ascorbic acid and 0.03~0.08 wt% fatty alcohol polyoxyethylene ether.

[0012] In S3, the sulfurized fixed clinker and sulfuric acid leachate are mixed at a liquid-to-solid ratio of 5~8 / 1mL / g; In S3, the leaching is carried out under an inert atmosphere at 75~90℃ with stirring for 3~6 hours to avoid the sulfide impurities being oxidized and dissolved during the leaching process.

[0013] In S3, the solid-liquid separation requires collecting the germanium-containing leachate and discarding the silicon-containing leachate residue.

[0014] In S4, the amine extractant is one or a mixture of two of N235 and N1923, and the volume fraction of the amine extractant is 15-25%. In S4, the amine extractant also contains 5-10% by volume 2-octanol as a modifier, and the remainder is sulfonated kerosene as a diluent. In S4, the number of extraction stages in the multi-stage countercurrent extraction is 5 to 8, the O / A ratio is 1 to 3 / 1 (volume ratio), the extraction temperature is 25 to 40°C, the stirring speed is 150 to 250 rpm, and the single-stage extraction time is 5 to 10 min.

[0015] In S4, the alkaline back-extraction solution is a sodium hydroxide solution with a mass fraction of 8-15% or a sodium carbonate solution with a mass fraction of 10-20%. In S4, the number of back-extraction stages is 3 to 5, the O / A ratio is 3 to 5 / 1 (volume ratio), the back-extraction temperature is 30 to 50℃, and the single-stage back-extraction time is 8 to 12 minutes.

[0016] In S5, the hydrolysis precipitation is achieved by adding 5-10% dilute sulfuric acid by mass to a germanate solution, adjusting the pH of the solution to 2.5-3.5, and then stirring and hydrolyzing at 40-60°C for 1-2 hours. After hydrolysis and precipitation, the mixture is allowed to stand for 2-4 hours, and then the solid and liquid phases are separated to obtain pure germanium dioxide.

[0017] The purity of the germanium dioxide is ≥99.95%.

[0018] The total germanium recovery rate is ≥95%. The total germanium recovery rate refers to the percentage of germanium mass in pure germanium dioxide to the total germanium mass in germanium-silicon alloy waste.

[0019] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention uses oxidative roasting to convert elemental germanium in different waste materials into easily leached GeO2, while carbon impurities are oxidized to CO2 and released. Pyrite is used as a sulfiding agent in an inert atmosphere to allow impurity ions in the waste materials, such as Fe, Cu, and Zn, to combine with S to form stable sulfide precipitates, while simultaneously inhibiting GeO2 reduction.

[0021] 2. The complexing agent in the compound sulfuric acid leachate can complex Ge. 4+ To prevent hydrolysis, ascorbic acid inhibits Ge 4+ Oxidation and surfactants enhance solid-liquid penetration. Simultaneously, complexing agents mask residual impurity ions, further reducing interference from impurities.

[0022] 3. In the purification stage of this invention, germanium is first enriched through multi-stage countercurrent extraction, followed by back-extraction to further remove impurities, achieving deep separation of germanium from impurities. Finally, the germanate solution hydrolysis precipitation, through precise control of pH, temperature, and aging time, avoids co-precipitation of impurities, ensuring consistent product purity.

[0023] 4. The process of this invention has wide applicability and can efficiently recycle waste materials from infrared optical and laser devices, semiconductor device manufacturing, and photovoltaic device processing. No toxic reagents are used in the process; the leaching residue (high in silicon content) can be directly recycled as silicon raw material; and the sulfide fixation residue can be further recycled to recover metals such as Fe and Cu. This achieves full-component utilization of germanium-silicon alloy waste, resulting in high resource utilization and low wastewater discharge. It balances resource recovery and environmental protection, meeting the current needs of green industrial development. Detailed Implementation

[0024] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0026] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0027] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0028] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0029] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0030] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0031] Unless otherwise specified, the term "or" is inclusive in this invention. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0032] The raw material information used in the following examples is as follows: The germanium-silicon alloy waste originates from high-frequency germanium-silicon transistor processing waste. Its composition (mass percentage) is 6.8%Ge, 4.2%Fe, 1.5%Cu, 0.7%Al, 0.4%Zn, 1.0%C, other impurities (including Ca, Mg, Ni, etc.) 4.3%, and the balance Si.

[0033] Example 1 The process for recovering germanium from germanium-silicon alloy waste in this embodiment is as follows: S1. Pretreatment: Take 1000g of germanium-silicon alloy waste, crush it to a particle size ≤5cm, then ball mill and sieve to collect waste powder below 200 mesh; Oxidative roasting: The pretreated waste powder is placed in an electric heating constant temperature roasting furnace, air is introduced at a rate of 2L / min, the heating rate is 5℃ / min, the temperature is raised to 550℃ and then roasted at a constant temperature for 2 hours. After roasting, the temperature is naturally cooled to room temperature and 920g of roasted clinker is obtained.

[0034] S2. Weigh 46g of pyrite (5% of the mass of the roasted clinker) and mix it with the above roasted clinker. Place it in an electric heating constant temperature roasting furnace, introduce nitrogen gas at a rate of 1.5L / min, raise the temperature to 520℃ at 5℃ / min, and roast at a constant temperature for 1.2h. After roasting, continue to introduce nitrogen gas to cool to room temperature, and take out the activated clinker.

[0035] S3. Mix 2.5wt% citric acid, 2.0wt% oxalic acid, 0.5wt% ascorbic acid and 0.05wt% fatty alcohol polyoxyethylene ether with the balance of water, and then slowly add concentrated sulfuric acid dropwise until the pH of the sulfuric acid leachate is 1.5 to obtain the sulfuric acid leachate. The activated clinker and sulfuric acid leachate were mixed at a liquid-solid ratio of 6 / 1 mL / g. The beaker was placed in a constant temperature water bath stirrer, nitrogen gas was introduced at a rate of 1 L / min, the water bath temperature was set to 80℃, and the mixture was stirred and leached at a constant temperature for 4 hours. The pH was maintained at 1.5±0.2 during the leaching process. After leaching, solid-liquid separation is achieved by filtration. The collected liquid is the germanium-containing leachate, and the filter residue is recycled as silicon raw material. S4. Prepare the organic phase: Mix 20% N235, 8% 2-octanol and 72% sulfonated kerosene by volume, shake and mix, let stand to separate into layers, remove impurities and water from the lower layer to obtain the amine extractant; Multistage countercurrent extraction: A germanium-containing leachate (aqueous phase A) and amine extractant (organic phase O) are fed into a multistage countercurrent extraction column. The ratio of O / A is set to 2:1 (volume ratio), the extraction temperature is 30℃, the stirring speed of each stage is 200 rpm, and the extraction time per stage is 8 min. Countercurrent operation is adopted (aqueous phase enters from the bottom of the column, and organic phase enters from the top of the column). After extraction, the raffinate is discharged from the bottom of the column, and the loaded organic phase is collected from the top of the column. Alkaline back-extraction: The loaded organic phase (organic phase O) and the back-extraction solution (10% sodium hydroxide aqueous solution, aqueous phase A) are introduced into the extraction column (O / A ratio = 4:1); the back-extraction temperature is set to 40℃, the stirring speed is 250rpm, the number of back-extraction stages is 4, the single-stage back-extraction time is 10min, and the countercurrent operation is used (the back-extraction solution enters from the bottom of the column, and the loaded organic phase enters from the top of the column). After the back-extraction is completed, the back-extraction solution is collected from the bottom of the column, which is the germanate solution.

[0036] At a constant temperature of 50℃, 8% dilute sulfuric acid was added dropwise to the germanate solution to adjust the pH to 3.0, and the solution was continuously hydrolyzed by stirring at a constant temperature for 1.5 hours. After hydrolysis, the stirring was turned off, the water bath temperature was maintained at 50℃, and the solution was allowed to stand for 3 hours to allow the GeO2 crystals to grow fully and precipitate completely, forming a white flocculent precipitate. The aged slurry was vacuum filtered, and the filter cake was washed with deionized water until the pH of the washing liquid reached 6.5~7.0. The solution was then dried at 120℃ for 2 hours to obtain pure germanium dioxide.

[0037] Example 2 The difference between this embodiment and Embodiment 1 is as follows: The oxidation calcination in S1 was carried out at 600℃ for 1.5 hours; The other raw materials, steps and parameters are the same as in Example 1.

[0038] Example 3 The difference between this embodiment and Embodiment 1 is as follows: In S2, the amount of pyrite added is 2% of the mass of the roasted clinker, that is, 18.4g of pyrite is weighed out. The other raw materials, steps and parameters are the same as in Example 1.

[0039] Example 4 The difference between this embodiment and Embodiment 1 is as follows: The sulfuric acid leachate in S3 contains 1.5 wt% citric acid, 1.0 wt% oxalic acid, 0.5 wt% ascorbic acid, and 0.08 wt% fatty alcohol polyoxyethylene ether, with the remainder being water. The other raw materials, steps and parameters are the same as in Example 1.

[0040] Example 5 The difference between this embodiment and Embodiment 1 is as follows: The sulfuric acid leachate in S3 contains 2.5 wt% citric acid, 2.5 wt% oxalic acid, 0.2 wt% ascorbic acid, and 0.05 wt% fatty alcohol polyoxyethylene ether, with the remainder being water. The other raw materials, steps and parameters are the same as in Example 1.

[0041] Example 6 The difference between this embodiment and Embodiment 1 is as follows: The pH of the sulfuric acid leachate in S3 is 0.8; The other raw materials, steps and parameters are the same as in Example 1.

[0042] Example 7 The difference between this embodiment and Embodiment 1 is as follows: The sulfuric acid leachate in S3 is a sulfuric acid aqueous solution with a pH of 1.5, and does not contain citric acid, oxalic acid, ascorbic acid, or fatty alcohol polyoxyethylene ether. The other raw materials, steps and parameters are the same as in Example 1.

[0043] Example 8 The difference between this embodiment and Embodiment 1 is as follows: The number of extraction stages in S4 multi-stage countercurrent extraction is 5; The back-extraction solution in S4 is an 8% sodium hydroxide solution by mass. The other raw materials, steps and parameters are the same as in Example 1.

[0044] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: In this comparative example, the waste powder after S1 pretreatment was not subjected to oxidative roasting, but was directly subjected to S2 and subsequent processes. The other raw materials, steps and parameters are the same as in Example 1.

[0045] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: This comparative example did not proceed with the S2 process for the roasted clinker from S1, but instead directly proceeded with the S3 and subsequent processes. The other raw materials, steps and parameters are the same as in Example 1.

[0046] Test case The pure germanium dioxide products prepared in the above examples and comparative examples were analyzed by ICP-MS, and the test results are shown in Table 1.

[0047]

[0048] The results of the determination of impurity content in pure germanium dioxide are shown in Table 2.

[0049]

[0050] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this invention. It should be understood that the above descriptions are merely specific embodiments of this invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A process for recovering germanium from germanium-silicon alloy waste, characterized in that, Includes the following steps: S1. Oxidize and roast the germanium-silicon alloy waste to obtain roasted clinker; S2. Activated clinker is obtained by fixing roasted clinker and pyrite by sulfidation. S3. After leaching the activated clinker with sulfuric acid, solid-liquid separation is performed, and the germanium-containing leachate is collected. S4. The germanium-containing leachate is subjected to multi-stage countercurrent extraction using an amine extractant to obtain a loaded organic phase; then the loaded organic phase is back-extracted using an alkaline back-extraction solution to obtain a germanate solution; S5. Germanate solution was hydrolyzed to precipitate pure germanium dioxide; In S2, the vulcanization fixation is carried out by calcination at 500~550℃ for 1~1.5h under an inert atmosphere. In S2, the amount of pyrite added is 3-8% of the mass of the roasted clinker; In S3, the pH of the sulfuric acid leachate is 1.0~2.0; In S3, the sulfuric acid leachate contains 1.0~4.0wt% citric acid, 1.0~3.0wt% oxalic acid, 0.2~1.5wt% ascorbic acid and 0.02~0.10wt% fatty alcohol polyoxyethylene ether.

2. The process for recovering germanium from germanium-silicon alloy waste as described in claim 1, characterized in that, The germanium-silicon alloy waste contains the following chemical elements by mass percentage: 5~8%Ge, 3.0~5.5%Fe, 1.0~2.0%Cu, 0.3~1.0%Al, 0.2~0.6%Zn, 0.5~1.5%C, other impurity elements <5%, and the balance silicon; And / or, the germanium-silicon alloy waste originates from infrared optical and laser device waste, semiconductor device manufacturing waste, or photovoltaic device processing waste.

3. The process for recovering germanium from germanium-silicon alloy waste as described in claim 2, characterized in that, S1 also includes a pretreatment process for the germanium-silicon alloy waste, wherein the pretreatment involves crushing and grinding the germanium-silicon alloy waste to 80-200 mesh. And / or, in S1, the oxidative calcination is calcination at 520~620℃ for 1~3h in an oxidizing atmosphere.

4. The process for recovering germanium from germanium-silicon alloy waste as described in claim 1, characterized in that, In S3, the clinker obtained by sulfurization fixation and the sulfuric acid leachate are mixed at a liquid-solid ratio of 5~8 / 1 mL / g. And / or, in S3, the leaching is carried out by stirring at 75~90°C for 3~6 hours under an inert atmosphere; And / or, in S3, the solid-liquid separation requires collecting the germanium-containing leachate and discarding the silicon-containing leachate residue.

5. The process for recovering germanium from germanium-silicon alloy waste as described in claim 1, characterized in that, In S4, the amine extractant is one or a mixture of two of N235 and N1923, and the volume fraction of the amine extractant is 15-25%. And / or, in S4, the amine extractant further comprises 5-10% by volume of 2-octanol as a modifier, with the remainder being sulfonated kerosene as a diluent. And / or, in S4, the number of extraction stages in the multi-stage countercurrent extraction is 5 to 8, the ratio of O / A is 1 to 3 / 1, the extraction temperature is 25 to 40°C, and the single-stage extraction time is 5 to 10 min.

6. The process for recovering germanium from germanium-silicon alloy waste as described in claim 5, characterized in that, In S4, the alkaline back-extraction solution is a sodium hydroxide solution with a mass fraction of 8-15% or a sodium carbonate solution with a mass fraction of 10-20%. And / or, in S4, the number of back-extraction stages is 3 to 5, the ratio of O / A is 3 to 5 / 1, the back-extraction temperature is 30 to 50°C, and the single-stage back-extraction time is 8 to 12 min.

7. The process for recovering germanium from germanium-silicon alloy waste as described in claim 1, characterized in that, The hydrolysis precipitation is achieved by adding 5-10% dilute sulfuric acid to a germanate solution, adjusting the pH of the solution to 2.5-3.5, and then stirring the solution at 40-60°C for 1-2 hours. And / or, after the hydrolysis precipitation is completed, the mixture is allowed to stand for 2-4 hours, and then the solid and liquid are separated to obtain pure germanium dioxide.

8. The process for recovering germanium from germanium-silicon alloy waste as described in any one of claims 1 to 7, characterized in that, Germanium recovery rate ≥95%.

9. The process for recovering germanium from germanium-silicon alloy waste as described in any one of claims 1 to 7, characterized in that, The purity of the germanium dioxide is ≥99.95%.

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