A method for recovering germanium from germanium-rich lead-zinc dregs by mechanical activation reduction method

Abstract

The present application belongs to the field of solid waste recycling, and discloses a method for recovering germanium from germanium-rich lead-zinc slag by mechanical activation reduction method. Specifically, the method comprises the following steps: (1) crushing the germanium-rich lead-zinc waste slag; (2) mixing the crushed germanium-rich lead-zinc waste slag with a reducing agent for mechanical activation reduction treatment, wherein the addition amount of the reducing agent is 1-2:1 in terms of the molar ratio of the reducing agent to the iron element in the raw material germanium-rich lead-zinc waste slag; the reducing agent is an organic acid; (3) performing acid leaching on the material after activation reduction in step (2), and then performing solid-liquid separation to obtain a germanium-containing leaching solution and a leaching residue; and (4) adding hydrochloric acid to the germanium-containing leaching solution, and then performing negative pressure distillation to obtain a crude germanium tetrachloride product after condensation. The present application not only greatly improves the recovery rate of germanium, but also simultaneously improves the leaching rate of valuable metals such as zinc and iron to more than 90%, which is conducive to the comprehensive resource utilization of multiple metals in waste slag and improves the overall economic value.

Description

Technical Field

[0001] This invention belongs to the field of solid waste recycling and treatment, and in particular relates to a method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction. Background Technology

[0002] Germanium, as a rare and dispersed metal, is widely used in optical fibers, infrared optics, chemical catalysts, and aerospace. Currently, germanium is mainly derived from zinc smelting byproducts. The hydrometallurgical process for zinc production generates a large amount of leaching residue, in which approximately 90% of the germanium is concentrated. Therefore, recovering germanium from lead-zinc waste has extremely high economic value and strategic resource significance.

[0003] However, efficient recovery of germanium from lead-zinc waste presents significant technical challenges. During hydrometallurgical zinc smelting, the roasting of zinc concentrate produces chemically stable zinc ferrite, in which germanium isomorphously replaced by iron or zinc and is firmly encapsulated. Furthermore, some germanium also combines with silicates. These phases exhibit high chemical stability and poor solubility under conventional acidic leaching conditions, resulting in consistently low germanium leaching rates. Even if a small amount of germanium is leached, it is readily adsorbed and co-precipitated by the Si(OH)4 polymers generated during the reaction, leading to secondary losses and further reducing germanium recovery efficiency.

[0004] Currently, the main industrial methods for treating germanium-rich lead-zinc waste residue include pyrometallurgical processes such as volatilization in volatilization kilns and fuming in fuming furnaces. While these methods have been used for some time, they suffer from insurmountable drawbacks: firstly, they are extremely energy-intensive, requiring high-temperature conditions; secondly, they generate large amounts of sulfur dioxide-containing flue gas, causing severe environmental pollution and necessitating large-scale, costly exhaust gas purification systems, further increasing operating costs; and thirdly, in pyrometallurgical processes, rare and dispersed metals such as germanium tend to disperse, making efficient enrichment and recovery difficult, resulting in a low overall recovery rate. To overcome the shortcomings of pyrometallurgical processes, hydrometallurgical technology has received widespread attention. Researchers have developed various hydrometallurgical leaching processes to improve germanium recovery rates, such as two-stage acid leaching, oxygen-pressure acid leaching, and reductive leaching. However, these methods all have their limitations: for example, patent application CN113832346A uses a first-stage low-acid pressure leaching followed by a second-stage pressure deep leaching, which significantly improves the leaching rate of germanium, but the improvement is limited; however, the lead, silver, and iron slag cannot be stably solidified and recycled. Another example is patent application CN106222429A, which discloses an oxygen-pressure acid leaching method to separate iron, but suffers from the problem of unrecoverable iron slag, high equipment requirements, large investment, and frequent maintenance, limiting its widespread application. The reduction leaching method disclosed in patent application CN119464729A has a long reduction time and requires high temperatures, resulting in still high energy consumption and operating costs.

[0005] In summary, there is an urgent need in this field to develop a new process that can achieve efficient, green, and low-cost recovery of germanium without relying on high-temperature and high-pressure equipment. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a short-process green method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, which has high leaching efficiency, low energy consumption, short process, simple equipment, and is environmentally friendly.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0008] A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction includes the following steps: (1) Crushing germanium-rich lead-zinc waste residue; (2) The crushed germanium-rich lead-zinc waste residue and the reducing agent are mixed and mechanically activated and reduced. The amount of the reducing agent added is calculated based on the molar ratio of the reducing agent to the iron element in the raw material germanium-rich lead-zinc waste residue, which is (1-2):1; the reducing agent is an organic acid. (3) The material after activation and reduction in step (2) is subjected to acid leaching and solid-liquid separation to obtain germanium-containing leachate and leachate residue; (4) Add hydrochloric acid to the germanium-containing leachate, then perform negative pressure distillation, and condense to obtain crude germanium tetrachloride product.

[0009] In the above-mentioned method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (2), the organic acid is oxalic acid.

[0010] In the above-mentioned method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (2), the mechanical activation reduction treatment is carried out in a planetary ball mill with a ball-to-material mass ratio of (7-15):1.

[0011] In the above-mentioned method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (2), the rotation speed of the planetary ball mill is 500-700 r / min, and the mechanical activation reduction treatment time is 60-120 min.

[0012] In the above-mentioned method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (1), the particle size of the germanium-rich lead-zinc slag after crushing is 1-2 mm.

[0013] In the above-mentioned method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (3), the acid leaching is performed using a sulfuric acid solution with a concentration of 1-2 mol / L, the leaching temperature is 70-90℃, the liquid-to-solid volume ratio is (5-8):1, and the leaching time is 60-120 min.

[0014] In the above-mentioned method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (4), after adding hydrochloric acid, the concentration of hydrochloric acid in the solution is 80-100 g / L.

[0015] The method described above for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction is preferably performed in step (4) under the following conditions: distillation temperature 90-120℃, system pressure -0.01 MPa to -0.015 MPa, and distillation time 60-90 min.

[0016] In the above-mentioned method of recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, preferably, in step (4), condensation is carried out using circulating water cooling, and the cooling temperature is not higher than 35°C.

[0017] The method described above for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction is preferably wherein the chemical composition of the germanium-rich lead-zinc slag includes 10.81-20.86% zinc, 1.55-2.55% germanium, 3.50-5.15% iron, and 3.48-6.34% silicon.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention utilizes mechanochemical activation to disrupt the physicochemical structure of germanium-rich slag, significantly improving the leaching rate and reaction rate of germanium and other valuable metals during acid leaching. The mechanical effect of high-energy ball milling can violently disrupt the stable mineral lattice in lead-zinc waste slag, fully exposing the encapsulated germanium. At the same time, the organic acid reducing agent undergoes a highly efficient reduction reaction with the exposed high-valence metal ions under mechanical force, generating a phase that is more soluble in acid. This synergistic effect of physical cell disruption and chemical reduction fundamentally solves the technical bottleneck of germanium's difficulty in leaching from stable phases.

[0019] (2) During the mechanical activation process of this invention, iron ions react with oxalate ions to form ferrous oxalate precipitate. This precipitation process effectively inhibits the hydrolysis reaction of iron ions in the solution, thereby significantly reducing the adsorption of germanium by iron and reducing the loss of germanium. At the same time, this step achieves the recovery of some iron elements. In addition, during the leaching process, excess oxalic acid can form stable complexes with elements such as germanium, zinc, and silicon; the formation of complexes significantly improves the solubility of germanium in the solution, facilitating the selective separation and recovery of germanium by subsequent vacuum distillation technology.

[0020] (3) The entire mechanical activation process of the present invention is carried out at room temperature, without the need for external heating, and has low energy consumption.

[0021] (4) The entire process of the present invention is a wet operation, and the mechanical activation is carried out in a closed polytetrafluoroethylene ball mill jar, which effectively prevents the volatilization of dust and harmful gases, improves the working environment, and eliminates the problem of SO2 and other harmful gas emissions.

[0022] (5) This invention not only greatly improves the recovery rate of germanium, but also simultaneously increases the leaching rate of valuable metals such as zinc and iron to over 90%, which is conducive to the comprehensive resource utilization of multiple metals in waste residue and enhances the overall economic value. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a process flow diagram of the mechanical activation reduction method used in an embodiment of the present invention to recover germanium from germanium-rich lead-zinc slag.

[0025] Figure 2 This is the XRD pattern of germanium-rich lead-zinc slag raw material used in Embodiment 1 of the present invention.

[0026] Figure 3 This is the XRD pattern of germanium-zinc rich slag after mechanical activation and grinding in Example 1 of the present invention. Detailed Implementation

[0027] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0028] 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.

[0029] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0030] The planetary ball mill used in the following embodiments uses a polytetrafluoroethylene (PTFE) ball mill jar and zirconia balls as the grinding media.

[0031] Example 1: A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction according to the present invention, the process flow diagram of which is shown in Figure 1, includes the following steps: (1) The germanium-rich lead-zinc waste residue (main element content: zinc 12.81%, germanium 2.15%, iron 3.61%, silicon 4.34%) was crushed to a particle size of 1-2 mm. The XRD pattern of the germanium-rich lead-zinc waste residue is shown below. Figure 2 As shown, the main chemical components of this raw material are PbSO4, zinc ferrite (ZnFe2O4) sulfide, and silicon oxide phase.

[0032] (2) Based on the molar ratio of iron to oxalic acid (analytical grade dihydrate, effective mass fraction of 72.7%) in the germanium-rich lead-zinc waste residue of raw material, the crushed germanium-rich lead-zinc waste residue and oxalic acid were uniformly mixed at a mass ratio of 20:1.6, and then placed in a planetary ball mill for mechanochemical activation treatment. The ball mill speed was set to 600 r / min, the ball milling time was 1.0 h, and the ball-to-material mass ratio was 10:1. After the ball milling was completed, the activated mixture was taken out of the ball mill jar and dried to obtain the mechanically activated modified slag. Its XRD is as follows: Figure 3 As shown; from Figure 3 It can be seen that after mechanical activation modification, magnesium silicate (MgO) and iron oxalate (FeC2O4·2H2O) appear.

[0033] (3) The mechanically activated modified slag obtained in step (2) was placed in a 1 mol / L sulfuric acid solution for leaching reaction. The leaching temperature was controlled at 75℃, the leaching time was 2 h, the liquid-to-solid volume ratio was 8:1, and after the reaction was completed, the leaching slurry was separated into liquid and solid, the leaching liquid was collected, and the content of each element was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the leaching efficiency of zinc, iron and germanium reached 90.87%, 93.78% and 92.34%, respectively.

[0034] (4) Add hydrochloric acid to the leachate obtained in step (3) until the hydrochloric acid concentration is 100 g / L, and carry out negative pressure distillation. The negative pressure distillation is carried out at a temperature of 95℃ and -0.01 MPa for about 70 minutes until germanium tetrachloride is completely distilled off. The cooling temperature of the circulating water in the condensation system is not higher than 35℃. The circulating water is used to condense the germanium tetrachloride gas. The recovery rate of germanium tetrachloride is 85.56%.

[0035] Comparative Example 1: The only difference between this comparative example and Example 1 is that oxalic acid was not introduced during the mechanical activation process in step (2), while other process parameters were the same as in Example 1. Analysis of the leachate in step (3) showed that the leaching efficiencies for zinc, iron, and germanium were 72.47%, 84.17%, and 71.16%, respectively, significantly lower than the oxalic acid-assisted mechanical activation process in Example 1. In step (4), the recovery rate of germanium tetrachloride was 74.48%.

[0036] Example 2: A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction according to the present invention, the process flow diagram of which is shown in Figure 1, includes the following steps: (1) The germanium-rich lead-zinc waste residue (main element content: zinc 11.56%, germanium 1.74%, iron 3.82%, silicon 3.74%) is crushed to a particle size of 1-2 mm.

[0037] (2) The crushed germanium-zinc-rich slag and oxalic acid were mixed evenly at a mass ratio of 20:2.5 (this ratio was calculated based on the molar ratio of iron to oxalic acid of 1:1.5 in the raw material germanium-zinc-rich slag). Then, the mixture was placed in a planetary ball mill for mechanical and chemical activation treatment. The ball mill speed was set to 600 r / min, the ball milling time was 1.0 h, and the ball-to-material mass ratio was 10:1. After the ball milling was completed, the activated mixture was taken out of the ball mill jar and dried to obtain mechanically activated modified slag.

[0038] (3) The mechanically activated modified slag obtained in step (2) was placed in a 1 mol / L sulfuric acid solution for leaching reaction. The leaching temperature was controlled at 75℃, the leaching time was 2 h, and the liquid-solid ratio was 8:1. After the reaction was completed, the leaching slurry was separated into liquid and solid, and the leaching liquid was collected. The content of each element was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the leaching efficiencies of zinc, iron and germanium reached 96.87%, 94.43% and 97.53%, respectively.

[0039] (4) Add hydrochloric acid to the leachate obtained in step (3) until the hydrochloric acid concentration is 100 g / L, and carry out negative pressure distillation. The negative pressure distillation is carried out at a temperature of 95℃ and -0.01 MPa for about 75 min until germanium tetrachloride is completely distilled off. The cooling temperature of the circulating water in the condensation system is not higher than 35℃. The circulating water is used to condense the germanium tetrachloride gas. The recovery rate of germanium tetrachloride is 85.97%.

[0040] Comparative Example 2: The only difference between this comparative example and Example 2 is that the mechanical activation treatment in step (2) was omitted. Instead, the crushed germanium-rich lead-zinc waste residue was directly mixed with oxalic acid and then subjected to sulfuric acid leaching in step (3). Other process parameters were the same as in Example 1. The analysis results of the leachate in step (3) showed that the leaching efficiencies of zinc, iron, and germanium were 85.64%, 91.94%, and 90.47%, respectively, which were significantly lower than those of the oxalic acid-assisted mechanical activation treatment process in Example 1.

[0041] Comparative Example 3: The only difference between this comparative example and Example 2 is that oxalic acid was not introduced during the mechanical activation process in step (2), while the other process parameters were the same as in Example 1. The leaching solution analysis results in step (3) showed that the leaching efficiencies of zinc, iron, and germanium were 76.15%, 83.15%, and 67.64%, respectively, which were significantly lower than the oxalic acid-assisted mechanical activation process in Example 1; in step (4), the recovery rate of germanium tetrachloride was 74.61%.

[0042] Example 3: A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction according to the present invention, the process flow diagram of which is shown in Figure 1, includes the following steps: (1) The germanium-rich lead-zinc waste residue (main element content: zinc 13.63%, germanium 2.77%, iron 3.42%, silicon 3.32%) is crushed to a particle size of 1-2 mm.

[0043] (2) The crushed germanium-zinc-rich slag and oxalic acid were mixed evenly at a mass ratio of 20:1.6 (the molar ratio of iron to oxalic acid in the raw material germanium-zinc-rich waste slag was 1:1). Then, the mixture was placed in a planetary ball mill for mechanical and chemical activation treatment. The ball mill speed was set to 500 r / min, the ball milling time was 1.5 h, and the ball-to-material mass ratio was 15:1. After the ball milling was completed, the activated mixture was taken out of the ball mill jar and dried to obtain mechanically activated modified slag.

[0044] (3) The mechanically activated modified slag obtained in step (2) was placed in a 1.5 mol / L sulfuric acid solution for leaching reaction. The leaching temperature was controlled at 70℃, the leaching time was 2 h, and the liquid-solid ratio was 8:1. After the reaction was completed, the leaching slurry was separated into liquid and solid, and the leaching liquid was collected. The content of each element was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the leaching efficiency of zinc, iron and germanium reached 95.73%, 90.56% and 94.46%, respectively.

[0045] (4) Add hydrochloric acid to the leachate obtained in step (3) until the hydrochloric acid concentration is 100 g / L, and carry out negative pressure distillation. The negative pressure distillation is carried out at a temperature of 95℃ and -0.01 MPa for about 80 minutes until germanium tetrachloride is completely distilled off. The cooling temperature of the circulating water in the condensation system is not higher than 35℃. Cold brine is used to condense germanium tetrachloride gas. The recovery rate of germanium tetrachloride reaches 86.87%.

[0046] Comparative Example 4: The only difference between this comparative example and Example 3 is that oxalic acid was replaced with activated carbon in the mechanical activation process of step (2), and the germanium-rich zinc slag and activated carbon were uniformly mixed at a mass ratio of 200:7 (the molar ratio of iron to activated carbon in the germanium-rich lead-zinc waste slag was 1:1). Other process parameters were the same as in Example 3. The leaching solution analysis results in step (3) showed that the leaching efficiencies of zinc, iron, and germanium were 96.15%, 90.15%, and 91.47%, respectively. In step (4), the recovery rate of germanium tetrachloride was 77.46%.

[0047] Example 4: A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction according to the present invention includes the following steps: (1) The germanium-rich lead-zinc waste residue (main element content: zinc 13.63%, germanium 2.77%, iron 3.42%, silicon 3.32%) is crushed to a particle size of 1-2 mm.

[0048] (2) The crushed germanium-zinc-rich slag and oxalic acid were mixed evenly at a mass ratio of 20:3 (the molar ratio of iron to oxalic acid in the germanium-zinc-rich slag was 1:2). Then, the mixture was placed in a planetary ball mill for mechanical and chemical activation treatment. The ball mill speed was set to 700 r / min, the ball milling time was 1.0 h, and the ball-to-material mass ratio was 7:1. After the ball milling was completed, the activated mixture was taken out of the ball mill jar and dried to obtain mechanically activated modified slag.

[0049] (3) The mechanically activated modified slag obtained in step (2) was placed in a 1 mol / L sulfuric acid solution for leaching reaction. The leaching temperature was controlled at 80℃, the leaching time was 1h, and the liquid-solid ratio was 10:1. After the reaction was completed, the leaching slurry was separated into liquid and solid, and the leaching liquid was collected. The content of each element was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the leaching efficiency of zinc, iron and germanium reached 94.43%, 91.66% and 96.47%, respectively.

[0050] (4) Add hydrochloric acid to the leachate obtained in step (3) until the hydrochloric acid concentration is 100 g / L, and carry out negative pressure distillation. The negative pressure distillation is carried out at a temperature of 95℃ and -0.01 MPa for about 80 minutes until germanium tetrachloride is completely distilled off. The cooling temperature of the circulating water in the condensation system is not higher than 35℃. Cold brine is used to condense germanium tetrachloride gas. The recovery rate of germanium tetrachloride can reach 86.20%.

[0051] Example 5: A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction according to the present invention includes the following steps: (1) The germanium-rich lead-zinc waste residue (main element content: zinc 13.63%, germanium 2.77%, iron 3.42%, silicon 3.32%) is crushed to a particle size of 1-2 mm.

[0052] (2) The crushed germanium-zinc-rich slag and oxalic acid were mixed evenly at a mass ratio of 20:2.5 (the molar ratio of iron to oxalic acid in the raw material germanium-zinc-rich slag was 1:1.5). Then, the mixture was placed in a planetary ball mill for mechanical and chemical activation treatment. The ball mill speed was set to 600 r / min, the ball milling time was 1 h, and the ball-to-material mass ratio was 10:1. After the ball milling was completed, the activated mixture was taken out of the ball mill jar and dried to obtain mechanically activated modified slag.

[0053] (3) The mechanically activated modified slag obtained in step (2) was placed in a 2 mol / L sulfuric acid solution for leaching reaction. The leaching temperature was controlled at 80℃, the leaching time was 1h, and the liquid-solid ratio was 5:1. After the reaction was completed, the leaching slurry was separated into liquid and solid, and the leaching liquid was collected. The content of each element was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the leaching efficiency of zinc, iron and germanium reached 94.72%, 91.34% and 96.21%, respectively.

[0054] (4) Add hydrochloric acid to the leachate obtained in step (3) until the hydrochloric acid concentration is 100 g / L, and carry out negative pressure distillation. The negative pressure distillation is carried out at a temperature of 95℃ and -0.01 MPa for about 80 minutes until germanium tetrachloride is completely distilled off. The cooling temperature of the circulating water in the condensation system is not higher than 35℃. Cold brine is used to condense germanium tetrachloride gas. The recovery rate of germanium tetrachloride can reach 84.64%.

[0055] Comparative Example 5: The only difference between this comparative example and Example 5 is that oxalic acid was replaced with tartaric acid in the mechanical activation process of step (2), and the germanium-rich zinc slag and activated carbon were uniformly mixed at a mass ratio of 20:2.5. Other process parameters were the same as in Example 5. The leaching solution analysis results in step (3) showed that the leaching efficiencies of zinc, iron, and germanium were 93.16%, 94.15%, and 95.46%, respectively. In step (4), the recovery rate of germanium tetrachloride was 57.14%.

Claims

1. A method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction, characterized in that, Includes the following steps: (1) Crushing germanium-rich lead-zinc waste residue; (2) The crushed germanium-rich lead-zinc waste residue and the reducing agent are mixed and mechanically activated and reduced. The amount of the reducing agent added is calculated based on the molar ratio of the reducing agent to the iron element in the raw material germanium-rich lead-zinc waste residue, which is (1-2):1; the reducing agent is an organic acid. (3) The material after activation and reduction in step (2) is subjected to acid leaching and solid-liquid separation to obtain germanium-containing leachate and leachate residue; (4) Add hydrochloric acid to the germanium-containing leachate, then perform negative pressure distillation, and condense to obtain crude germanium tetrachloride product.

2. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (2), the organic acid is oxalic acid.

3. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (2), the mechanical activation and reduction treatment is carried out in a planetary ball mill with a ball-to-material mass ratio of (7-15):

1.

4. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 3, characterized in that, In step (2), the rotation speed of the planetary ball mill is 500-700 r / min, and the mechanical activation and reduction treatment time is 60-120 min.

5. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (1), the particle size of the germanium-rich lead-zinc waste residue after crushing is 1-2 mm.

6. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (3), the acid leaching is carried out using a sulfuric acid solution with a concentration of 1-2 mol / L, the leaching temperature is 70-90℃, the liquid-to-solid volume ratio is (5-8):1, and the leaching time is 60-120 min.

7. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (4), after adding hydrochloric acid, the concentration of hydrochloric acid in the solution is 80-100 g / L.

8. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (4), the conditions for negative pressure distillation are: distillation temperature 90-120℃, system pressure -0.01 MPa to -0.015 MPa, and distillation time 60-90 min.

9. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, In step (4), condensation is achieved by circulating water cooling, with the cooling temperature not exceeding 35°C.

10. The method for recovering germanium from germanium-rich lead-zinc slag using mechanical activation reduction as described in claim 1, characterized in that, The chemical composition of the germanium-rich lead-zinc waste residue includes 10.81-20.86% zinc, 1.55-2.55% germanium, 3.50-5.15% iron, and 3.48-6.34% silicon.

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