Process for improving the leaching rate of germanium from germanium-containing zinc suboxide

Abstract

The present application relates to a kind of process for improving germanium leaching rate in germanium-containing zinc suboxide, belong to hydrometallurgy technical field, the present application includes: (1) germanium-containing zinc suboxide dust grinds slurry, (2) low acid leaching in germanium-containing zinc suboxide after slurry, (3) enrichment germanium is carried out to leaching clear liquid, (4) after germanium-poor liquid oxidation and iron and (5) part of iron underflow returns low acid mixed leaching, (6) low acid leaching slag carries out high acid leaching six main steps, by returning to low acid leaching with iron underflow, insoluble sulfide in germanium-containing zinc suboxide and iron in iron underflow react into solution.The present application is aimed at the problem of low leaching rate in traditional two-stage countercurrent leaching process, by adjusting process and controlling process index, effectively improve germanium leaching rate, and the whole process does not need additional auxiliary materials, process is simple, and slag is low.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically, it relates to a process for improving the germanium leaching rate in germanium-containing zinc oxide. Background Technology

[0002] Germanium-containing zinc oxide dust is an intermediate raw material mainly containing valuable metals such as zinc, lead, germanium, and silver, produced after treating hydrometallurgical zinc smelting and pyrometallurgical lead slag using the pyrometallurgical fumigation and volatilization method. Germanium in germanium-containing zinc oxide dust is currently the main source of germanium. Currently, the recovery of germanium from zinc oxide dust generally adopts a two-stage countercurrent leaching process: first, a low-acid leaching stage introduces germanium into the leachate, and then tannin precipitation recovers the germanium from the leachate. During the first leaching stage, the pH value of the leachate must be strictly controlled between 2.0 and 3.5. Under high-acid conditions, H4SiO4 reacts with positively charged H5SiO4. + Hydroxylation reaction occurs to form dimer silica. The higher the acid concentration, the faster the polymerization rate. As polymerization accelerates, the dimer gradually grows into disordered high-polysilicic acid, and the particles gradually enlarge into irregular aggregates. Therefore, excessively high acidity will cause a large amount of silicon to be leached from the high-silicon, low-germanium slag. The silica will then continue to polymerize, eventually forming silica gel with a large specific surface area and high activity. This not only affects liquid-solid separation, but also increases the adsorption loss of germanium due to the large amount of exposed Si-OH on the surface of the disordered large particles. Therefore, conventional two-stage countercurrent leaching only achieves a germanium leaching rate of 50-70%. Although significant technological breakthroughs have been made in recent years, with process improvements and the use of pressure leaching, the germanium leaching rate in industrial applications has been increased to 85%, but it has not yet exceeded 90%. Therefore, how to improve the germanium leaching rate and reduce the germanium content in the final leaching residue (lead-silver slag) is a key factor restricting the germanium recovery rate.

[0003] Oxygen pressure leaching is an effective method to improve the leaching rates of zinc and germanium. CN108179289A discloses "A method for recovering germanium from zinc oxide dust," which provides a two-stage countercurrent leaching process: a stage of atmospheric pressure, low temperature, and low acid leaching, and a stage of high temperature oxygen pressure leaching. Sodium sulfite is used to reduce the leachate. CN108486383A discloses "A method for efficiently extracting zinc and germanium from zinc oxide dust," which also provides a two-stage countercurrent leaching process: a stage of atmospheric pressure, low temperature, and low acid leaching, and a stage of oxygen pressure, low temperature, and high acid leaching. Compared to atmospheric pressure leaching, oxygen pressure leaching significantly increases the leaching rates of zinc and germanium. However, compared to atmospheric pressure leaching, it requires more sophisticated equipment, and the concentration of ferric iron in the leachate is difficult to control. High concentrations of ferric iron have a significant impact on subsequent germanium recovery from the leachate, necessitating a dedicated reduction process to ensure that the iron in the leachate is ferrous iron (Fe2+). CN110184482A discloses a "leaching process for germanium-containing zinc oxide powder". By optimizing and adjusting the process flow configuration, it achieves efficient leaching of zinc and germanium, reduction of iron ions, and control of pH of the leaching solution in steps, solving problems such as efficient leaching of zinc and germanium and control of trivalent iron in the leaching solution during smelting. However, the low-acid leaching step requires the use of industrial oxygen or hydrogen peroxide, which increases the consumption of auxiliary materials and thus increases the processing cost. Summary of the Invention

[0004] To overcome the problems existing in the background technology, the present invention provides a process for improving the germanium leaching rate in germanium-containing zinc oxide. In view of the problem of low leaching rate in the traditional two-stage countercurrent leaching process, the germanium leaching rate is effectively improved by adjusting the process and controlling the process indicators. Moreover, the entire process does not require the addition of auxiliary materials, is simple, and has low tannin consumption.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: The process for improving the germanium leaching rate in germanium-containing zinc oxide includes the following steps: (1) Slurrying: Grind and slurry the germanium-containing zinc oxide.

[0006] (2) Low acid leaching: The germanium-containing zinc oxide pulp is leached with low acid, and the pH value at the leaching endpoint is 0.5-2.5.

[0007] (3) Precipitation of germanium: The leachate is used to precipitate germanium.

[0008] (4) Iron oxide precipitation: Iron is precipitated by tannin precipitation of germanium.

[0009] (5) Underflow return of sludge: Underflow return of sludge to step (2).

[0010] Furthermore, the dry basis of the iron-containing bottom flow in step (5) returning to step (2) is 20-35% of the dry basis of the germanium-containing zinc oxide powder in step (1).

[0011] Furthermore, the reaction temperature for the low-acid leaching in step (2) is 60~65℃, and the reaction time is 1.0~1.5h.

[0012] Furthermore, the leaching bottom stream from step (2) is subjected to high acid leaching at a leaching reaction temperature of 65~70℃ for 1.5~2h, with an leaching endpoint acidity of 20~30g / L.

[0013] Furthermore, after adding a reducing agent to the high-acid leaching bottom stream to leach zinc, the solution is filtered, and the filtrate is returned to step (2).

[0014] Furthermore, in step (2), sulfuric acid solution and bottom iron leaching are added; the sulfuric acid solution is a mixture of wet zinc electrolytic waste liquid and high acid leaching liquid, and the dry weight of secondary zinc oxide powder to the volume ratio of sulfuric acid solution is 100g: 500~600ml.

[0015] Furthermore, the leaching pH value in step (2) is 1.5-2.5.

[0016] Furthermore, the bottom runoff contains 26-30 wt% iron and 5-10 wt% zinc.

[0017] Furthermore, in step (5), there is no return to the bottom flow filtration of the iron sink in step (2), and the filtrate is returned to step (1).

[0018] Furthermore, zinc is recovered from the supernatant of the iron oxide precipitation in step (5).

[0019] The beneficial effects of this invention are: In this invention, germanium is recovered primarily in a low-acid leaching solution, while the low-acid leaching residue is further leached with high acid. After germanium is precipitated in the resulting low-acid leaching solution, iron is oxidized and deposited, with the iron underflow portion returned to the low-acid leaching step. The high-acid leaching solution is also returned to the low-acid leaching step. By controlling the low-acid leaching conditions, the germanium recovery rate is effectively improved.

[0020] This invention, through the control of process and process parameters, achieves a higher germanium leaching rate and better filtration performance of the resulting leachate compared to the existing two-step countercurrent leaching process. The process and equipment are simple, the operation is easy, the process is easy to control, and no additional auxiliary materials are added to the entire leaching process. Attached Figure Description

[0021] Figure 1 This is a simplified process flow diagram of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0023] The process for improving the germanium leaching rate in germanium-containing zinc oxide includes the following steps: (1) Slurrying: Add germanium-containing zinc oxide to water or zinc-germanium washing water to make slurry, and then slurry by wet ball milling.

[0024] (2) Low-acid leaching: The slurry containing germanium secondary zinc oxide is added to the wet zinc smelting electrolytic waste liquid, high-acid leaching solution and iron-laden underflow for low-acid leaching. The leaching temperature is 60~65℃, the leaching time is 1.0~1.5h, and the pH value at the leaching endpoint is 0.5-2.5, yielding clear leaching solution and leaching underflow. The dry weight ratio of secondary zinc oxide powder to the volume of wet zinc smelting electrolytic waste liquid and high-acid leaching solution is 100g:500~600ml.

[0025] After multiple experiments, it was found that adding a bottom flow of precipitated iron during low-acid leaching reduces the formation of gelatinous substances, not only improving the leaching rate of germanium but also resulting in faster clarification and easier filtration of the leachate. The bottom flow of precipitated iron (dry basis) is 20-35% of the mass of the germanium-containing zinc oxide powder (dry basis) from step (1). The higher the return flow of precipitated iron during low-acid leaching, the higher the leaching rate. However, due to the limitations of the raw material properties, the leaching rate is best controlled at around 90%. Excessive return will increase the cost of recycling. Therefore, although increasing the return amount is beneficial for improving the germanium leaching rate, excessive return will have the adverse effects of reduced production capacity and increased production costs. Therefore, the preferred return amount is 20-35%. In addition, a low-acid leaching process is performed using a bottom flow of precipitated iron, with the leaching pH controlled between 0.5 and 2.5. pH control is primarily considered from two aspects: the impact of silicic acid polymerization on filtration performance and the leaching rate of iron. A low pH increases the iron leaching rate, while an excessively high pH causes Fe3+ hydrolysis, reducing filtration performance and causing germanium precipitation. If the pH is too low, the leaching rate of valuable metals (germanium, zinc, etc.) decreases, and a large amount of silicon is leached out. The silicic acid then continues to polymerize, eventually forming highly active silica gel with a large specific surface area. This not only affects liquid-solid separation but also causes the exposed Si-OH on the disordered large particle surface to adsorb germanium, increasing germanium loss. A pH controlled between 1.8 and 2.2 achieves a high filtration or clarification rate while ensuring the leaching of valuable metals.

[0026] (3) Precipitation of germanium: The clear liquid from the low-acid leaching is subjected to germanium precipitation treatment to obtain germanium slag and germanium-poor liquid. Germanium precipitation can be carried out by tannin precipitation, extraction, displacement, neutralization and other processes to enrich germanium.

[0027] (4) High acid leaching: High acid leaching is carried out on the low acid leaching underflow. The high acid leaching conditions are: reaction temperature of 65~70℃, reaction time of 1.5~2h, and the acidity at the leaching endpoint of 20~30g / L. High acid leaching clear liquid and high acid leaching underflow are obtained. The high acid leaching clear liquid is returned to step (2).

[0028] The following reactions mainly occur during high-acid leaching:

[0029] β-FeOOH + H₂SO₄ → FeSO₄ + H₂O ZnO + H₂SO₄ → ZnSO₄ + H₂O GeO2 + H2SO4 → Ge(SO4)2 + H2O GeO + H₂SO₄ → GeSO₄ + H₂O (5) Iron precipitation: After germanium precipitation and filtration, the resulting filtrate is germanium-poor. Hydrogen peroxide and other oxidants are added to the germanium-poor filtrate to oxidize all the ferrous ions in the solution to ferric ions. The precipitated iron is oxidized and neutralized by spraying (EZ). After oxidation and precipitation, the solution is concentrated and clarified, resulting in iron precipitation underflow and iron precipitation clear liquid. The iron precipitation clear liquid is sent to the next process for further zinc recovery. Part of the iron precipitation underflow is returned to step (2), and part is filtered. The filtrate obtained from filtration is sent to step (1), and the filter residue is zinc-iron slag. The iron precipitation underflow (dry basis) contains 26~30wt% iron and 5~10wt% zinc.

[0030] The following reactions mainly occur in this step: Fe 2+ +H₂O₂ + H + →Fe 3+ +H2O Fe 3+ +2H₂O→β-FeOOH↓+H + (6) Add the wet zinc electrolytic waste liquid to the bottom stream of high acid leaching to continue leaching zinc, then filter, return the filtrate to step (2), and wash the filter residue with water to obtain lead slag, and return the wash water to step (1).

[0031] To illustrate the present invention more clearly, the following embodiments will be described in detail.

[0032] In the following examples, the main components of the germanium-containing zinc oxide powder used are: Zn: 48.89wt%, Fe: 0.96wt%, S: 5.9wt%, Pb: 8.52wt%, Ge: 0.170wt%, and the main components of the wet zinc smelting electrolytic waste liquid used are: H2SO4: 145g / L, Zn: 40g / L. Example 1

[0033] The process for improving the germanium leaching rate in germanium-containing zinc oxide includes the following steps: (1) Slurrying: Take 100g of fine zinc oxide powder containing germanium.

[0034] (2) Low acid leaching: Add 30g of wet zinc electrolytic waste liquid, high acid leaching liquid and iron precipitate bottom flow (dry basis) to germanium-containing zinc oxide powder, and carry out low acid leaching. The leaching temperature is 60~65℃, the leaching time is 1.5h, and the pH value at the leaching endpoint is 1.5 to obtain low acid leaching clear liquid and low acid leaching bottom flow.

[0035] (3) Take 125 ml of wet zinc electrolytic waste liquid and 175 ml of domestic water, add low acid leaching bottom stream, and carry out high acid leaching. The leaching temperature is 70~75℃, the leaching time is 2h, and the final acidity is 28g / L. After leaching, solid and liquid are separated to obtain high acid leaching residue and high acid leaching clear liquid. The high acid leaching residue is dried, weighed, sampled and analyzed. Vacuum filtration rate is 58ml / min. The high acid leaching residue contains 0.0359%wt germanium, and the germanium leaching rate is 90.23%.

[0036] (4) Germanium is enriched by precipitation in the clear solution of low acid leaching. After the germanium is precipitated, hydrogen peroxide is added to the germanium-poor solution to precipitate iron. After the iron is precipitated, the solution is concentrated and clarified. The supernatant is sent to the zinc electrowinning process. The iron underflow is returned to the part of step (2) for filtration. The filtered iron underflow residue is dried and analyzed. The main components are: Zn 7.90wt% and Fe 26.41wt%. The filtrate obtained from the iron underflow filtration is returned to step (2). Comparative Example 1

[0037] Except for the fact that the bottom flow of the sinking iron does not return to step (2), this comparative example is the same as Example 1.

[0038] (1) Slurrying: Take 100g of fine zinc oxide powder containing germanium.

[0039] (2) Low acid leaching: Add wet zinc electrolysis waste liquid and high acid leaching solution to germanium-containing zinc oxide powder, and carry out low acid leaching. The leaching temperature is 60~65℃, the leaching time is 1.5h, and the pH value at the leaching endpoint is 1.5, to obtain low acid leaching clear liquid and low acid leaching underflow.

[0040] (3) Take 125 ml of wet zinc electrolytic waste liquid and 175 ml of domestic water, add low acid leaching bottom stream, and carry out high acid leaching. The leaching temperature is 70~75℃, the leaching time is 2h, and the final acidity is 29g / L. After leaching, solid and liquid are separated to obtain high acid leaching residue and high acid leaching clear liquid. The high acid leaching residue is dried, weighed, sampled and analyzed. Vacuum filtration rate is 12ml / min. The high acid leaching residue contains 0.0847wt% germanium, and the germanium leaching rate is 68.18%.

[0041] (4) Germanium was enriched by precipitation of the clear solution of low acid leaching. After the germanium was precipitated, hydrogen peroxide was added to the germanium-poor solution to precipitate iron. After the iron was precipitated, the solution was concentrated and clarified. The supernatant was sent to the zinc electrowinning process. The iron was filtered through the underflow and dried. The main components were found to be: Zn 7.5wt% and Fe 27.1wt%. Example 2

[0042] The process for improving the germanium leaching rate in germanium-containing zinc oxide includes the following steps: (1) Slurrying: Add the zinc-germanium washing water from step (6) to the germanium-containing zinc oxide to form a slurry, and then wet ball mill it into a slurry.

[0043] (2) Low-acid leaching: The slurry containing germanium secondary zinc oxide is added to the wet zinc smelting electrolytic waste liquid, high-acid leaching solution and iron slurry for low-acid leaching. The dry weight of the secondary zinc oxide powder is 100g:500ml in volume ratio to the wet zinc smelting electrolytic waste liquid and high-acid leaching solution. The iron slurry (dry basis) is 20% of the mass of the germanium secondary zinc oxide powder (dry basis) in step (1).

[0044] The leaching temperature was 60~65℃, the leaching time was 1.0h, and the pH value at the leaching endpoint was 1.5 to obtain clear leachate and low-acid leaching underflow.

[0045] (3) Tannin precipitation of germanium: The clear solution of low acid leaching is subjected to tannin precipitation of germanium to obtain germanium slag and germanium-poor solution.

[0046] (4) High acid leaching: Add wet zinc electrolytic waste liquid to the low acid leaching underflow for high acid leaching. High acid leaching conditions: reaction temperature is 65~70℃, reaction time is 2h, and the acidity at the leaching endpoint is 30g / L. High acid leaching clear liquid and high acid leaching underflow are obtained. High acid leaching clear liquid is returned to step (2).

[0047] (5) Iron precipitation: Oxidizing agent is added to the germanium-poor solution to oxidize and neutralize the iron precipitation. After oxidation and precipitation, the solution is concentrated and clarified to obtain iron precipitation underflow and iron precipitation clear liquid. The iron precipitation clear liquid is sent to the electrowinning process to recover zinc. Part of the iron precipitation underflow is returned to step (2), and part is filtered. The filtrate after filtration is sent to step (1). The filter residue is zinc-iron slag. The filter residue contains 5.1 wt% iron and 19.36 wt% zinc on a dry basis. The germanium leaching rate is 89.44%.

[0048] (6) Add the wet zinc electrolytic waste liquid to the bottom stream of high acid leaching to continue leaching zinc, then filter, return the filtrate to step (2), and wash the filter residue with water to obtain lead slag, and return the wash water to step (1). Example 3

[0049] The process for improving the germanium leaching rate in germanium-containing zinc oxide includes the following steps: (1) Slurrying: Add the zinc-germanium washing water from step (6) to the germanium-containing zinc oxide to form a slurry, and then wet ball mill it into a slurry.

[0050] (2) Low-acid leaching: The slurry containing germanium secondary zinc oxide is added to the wet zinc smelting electrolytic waste liquid, high-acid leaching solution and iron slurry for low-acid leaching. The dry weight of the secondary zinc oxide powder is 100g:600ml in volume ratio to the wet zinc smelting electrolytic waste liquid and high-acid leaching solution. The iron slurry (dry basis) is 30% of the mass of the germanium secondary zinc oxide powder (dry basis) in step (1).

[0051] The leaching temperature was 60~65℃, the leaching time was 1.0h, and the pH value at the leaching endpoint was 2.0, yielding clear leachate and low-acid leaching underflow.

[0052] (3) Tannin precipitation of germanium: The clear solution of low acid leaching is subjected to tannin precipitation of germanium to obtain germanium slag and germanium-poor solution.

[0053] (4) High acid leaching: Add wet zinc electrolytic waste liquid to the low acid leaching underflow for high acid leaching. High acid leaching conditions: reaction temperature is 65~70℃, reaction time is 2h, and the acidity at the leaching endpoint is 30g / L. High acid leaching clear liquid and high acid leaching underflow are obtained. High acid leaching clear liquid is returned to step (2).

[0054] (5) Iron precipitation: Hydrogen peroxide is added to the germanium-poor solution to oxidize and neutralize the iron precipitation. After oxidation and precipitation, the solution becomes concentrated and clear, yielding iron precipitation underflow and iron precipitation clear liquid. The iron precipitation clear liquid is sent to the electrowinning process to recover zinc. Part of the iron precipitation underflow is returned to step (2), and part is filtered. The filtrate after filtration is sent to step (1), and the filter residue is zinc-iron slag. The filter residue contains 2.03 wt% iron, 21.4 wt% zinc, and 0.0347 wt% germanium on a dry basis, with a leaching rate of 90.51%.

[0055] (6) Add the wet zinc electrolytic waste liquid to the bottom stream of high acid leaching to continue leaching zinc, then filter, return the filtrate to step (2), and wash the filter residue with water to obtain lead slag, and return the wash water to step (1). Example 4

[0056] Other conditions were the same as in Example 3, except that the pH value of one leaching step was reduced to 1.5. The obtained iron precipitate filter residue contained 1.86 wt% iron, 20.8 wt% zinc, and 0.0364 wt% germanium on a dry basis, with a leaching rate of 89.08%. Example 5

[0057] Other conditions were the same as in Example 3, except that the pH of the first leaching step was increased to 2.5.

[0058] The obtained iron precipitate filter residue contained 2.13 wt% iron, 21.9 wt% zinc, and 0.0361 wt% germanium on a dry basis, with a leaching rate of 89.17%. Comparative Example 2

[0059] Everything else is the same as in Example 3, except that the leaching pH is increased to 3.0.

[0060] The obtained iron precipitate filter residue contained 2.30 wt% iron, 22.67 wt% zinc, and 0.0527 wt% germanium on a dry basis, with a leaching rate of 84.20%.

[0061] The clarification rate of the leachate decreased significantly, and the sedimentation time was extended from 3 hours in Example 3 to more than 6 hours. There were still some colloidal suspended matter in the supernatant.

[0062] The longer the precipitation time, the more severe the co-precipitation of silicon, iron, germanium, etc., which causes germanium that has been leached from the liquid phase to reprecipitate, thus affecting the leaching rate of germanium. The mechanism of mutual influence is too complex to study at present.

[0063] In addition, the polymerization reaction of silicic acid is ongoing. The longer the reaction lasts, the more silicic acid polymerizes, which has an adverse effect on filtration performance, clarification effect, and leaching of valuable metals. Comparative Example 3

[0064] The rest is the same as in Example 3, except that the pH value of the first leaching is reduced to 0.4 (approximately 15 g / L). The clarification rate of the leachate decreased significantly, and the sedimentation time was extended from 3 hours in Example 3 to more than 6 hours. There were still some colloidal suspended matter in the supernatant.

[0065] The obtained iron precipitate filter residue contained 1.81 wt% iron, 18.7 wt% zinc, and 0.0691 wt% germanium on a dry basis, with a leaching rate of 79.28%. Example 6

[0066] The process for improving the germanium leaching rate in germanium-containing zinc oxide includes the following steps: (1) Slurrying: Add the zinc-germanium washing water from step (6) to the germanium-containing zinc oxide to form a slurry, and then wet ball mill it into a slurry.

[0067] (2) Low-acid leaching: The slurry containing germanium secondary zinc oxide is added to the wet zinc smelting electrolytic waste liquid, high-acid leaching solution and iron slurry for low-acid leaching. The dry weight of the secondary zinc oxide powder is 100g:600ml in volume ratio to the wet zinc smelting electrolytic waste liquid and high-acid leaching solution. The iron slurry (dry basis) is 25% of the mass of the germanium secondary zinc oxide powder (dry basis) in step (1).

[0068] The leaching temperature was 60~65℃, the leaching time was 1.0h, and the pH value at the leaching endpoint was 1.8, yielding clear leachate and low-acid leaching underflow.

[0069] (3) Tannin precipitation of germanium: The clear solution of low acid leaching is subjected to tannin precipitation of germanium to obtain germanium slag and germanium-poor solution.

[0070] (4) High acid leaching: Add wet zinc electrolytic waste liquid to the low acid leaching underflow for high acid leaching. High acid leaching conditions: reaction temperature is 65~70℃, reaction time is 2h, and the acidity at the leaching endpoint is 30g / L. High acid leaching clear liquid and high acid leaching underflow are obtained. High acid leaching clear liquid is returned to step (2).

[0071] (5) Iron precipitation: Hydrogen peroxide is added to the germanium-poor solution to oxidize and neutralize the iron precipitation. After oxidation and precipitation, the solution becomes concentrated and clear, yielding iron precipitation underflow and iron precipitation clear liquid. The iron precipitation clear liquid is sent to the electrowinning process to recover zinc. Part of the iron precipitation underflow is returned to step (2), and part is filtered. The filtrate after filtration is sent to step (1), and the filter residue is zinc-iron slag. The filter residue contains 2.28 wt% iron, 22.63 wt% zinc, and 0.0386 wt% germanium on a dry basis, with a leaching rate of 89.44%.

[0072] (6) Add the wet zinc electrolytic waste liquid to the bottom stream of high acid leaching to continue leaching zinc, then filter, return the filtrate to step (2), and wash the filter residue with water to obtain lead slag, and return the wash water to step (1).

[0073] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A process for improving the germanium leaching rate in germanium-containing zinc oxide, characterized in that, Includes the following steps: (1) Slurrying: Grinding and slurrying germanium-containing zinc oxide; (2) Low acid leaching: The slurry containing germanium zinc oxide is subjected to low acid leaching to obtain low acid leaching supernatant and low acid leaching underflow. The pH value at the leaching endpoint is 0.5-2.

5. (3) Precipitation of germanium: The clear liquid from the low-acid leaching is subjected to germanium precipitation treatment to obtain germanium slag and germanium-poor liquid; (4) High acid leaching: The low acid leaching underflow from step (2) is subjected to high acid leaching to obtain high acid leaching supernatant and high acid leaching underflow; the leaching reaction temperature is 65-70℃, the reaction time is 1.5-2h, and the leaching endpoint acidity is 20-30g / L; the high acid leaching underflow is subjected to zinc leaching treatment, and the filtrate obtained after filtration is returned to step (2). (5) Oxidation precipitation of iron: The germanium-poor solution from step (3) is oxidized to precipitate iron, resulting in iron precipitate bottom flow and iron precipitate clear solution; (6) Returning the bottom flow of the sludge: Returning the bottom flow of the sludge from step (5) to step (2).

2. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1, characterized in that, Step (5) returns the dry basis mass of the sludge underflow from step (2) to be 20-35% of the dry basis mass of the germanium-containing zinc oxide in step (1).

3. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1, characterized in that, Step (2) The low acid leaching reaction temperature is 60-65℃ and the reaction time is 1.0-1.5h.

4. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1, characterized in that, In step (2), sulfuric acid solution and iron sludge underflow are added for low-acid leaching; the sulfuric acid solution is a mixture of wet zinc electrolysis waste liquid and high-acid leaching liquid; the ratio of the dry weight of germanium-containing zinc oxide to the volume of sulfuric acid solution is controlled to be 100g:500-600mL.

5. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1, characterized in that, In step (5), an oxidant is added to oxidize and precipitate iron. The oxidant used is oxygen, hydrogen peroxide, potassium permanganate or ozone.

6. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1, characterized in that, The leaching pH value in step (2) is 1.5-2.

5.

7. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1 or 2, characterized in that, The sludge that was not returned to step (2) in step (5) is filtered, and the resulting filtrate is returned to step (1).

8. The process for improving the germanium leaching rate in germanium-containing zinc oxide according to claim 1, characterized in that, The iron precipitate solution from step (5) is then subjected to zinc recovery treatment.

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