A method for separating lead and germanium from zinc oxide fume leaching residue

Abstract

The present application relates to a kind of zinc oxide smoke leaching residue lead germanium separation method, belong to the technical field of zinc hydrometallurgy, the present application includes the following steps: (1) zinc oxide smoke leaching residue is added into reactor, then zinc powder is added into reactor, and zinc powder and zinc oxide smoke leaching residue occur replacement reaction;(2) the reaction product in step (1) is pressure filtration, and after solid-liquid separation, pressure filtration liquid and pressure filtration residue are obtained;(3) the pressure filtration residue in step (2) is washed and slurried;(4) the washed and slurried product in step (3) is secondary pressure filtration, and after solid-liquid separation, secondary pressure filtration liquid and high lead residue are obtained;The present application utilizes the principle that lead sulfate and zinc are prone to replacement reaction, simplifies the separation method of lead germanium in zinc oxide smoke leaching residue, reduces separation cost, improves separation effect, and the pressure filtration liquid obtained by separation can be returned to leaching process as solvent, high lead residue can be used as raw material for pyrometallurgical lead, and the separation products can be recycled and reused, saving resources.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical zinc refining technology, specifically, it relates to a method for separating lead and germanium from zinc oxide leaching residue. Background Technology

[0002] With social development and increasing resource consumption, reducing resource waste and maximizing resource recycling rates have become key research directions in the manufacturing industry. The hydrometallurgical zinc smelting process faces numerous technical challenges in recovering valuable metals. Zinc oxide flue dust contains lead and germanium. Lead can be used as a raw material for lead smelting, while germanium plays an irreplaceable role in many high-tech fields. Therefore, it is necessary to recover and reuse the lead and germanium contained in zinc oxide flue dust.

[0003] In existing technologies, leaching is commonly used to recover and reuse lead and germanium from zinc oxide flue dust. Most leaching methods involve two-stage continuous acid leaching, which can leach out about 60% of the germanium. The remaining germanium is mainly co-existing with lead in the leaching residue. The germanium co-existing with lead in the leaching residue is directly fed into the pyrometallurgical lead smelting system for repeated processing. However, the recycling process is long, the technology is complex, and the production cost is high. Furthermore, the separation effect between lead and germanium is not ideal, which is not conducive to the economic recovery and utilization of lead and germanium. At the same time, due to the unsatisfactory separation effect, when the leaching residue is used as a raw material for lead smelting, its main grade Pb content is not high and it contains valuable metals such as Ge. Pyrometallurgical lead smelting ultimately yields crude lead or other lead products with low grade. Patent No. 201711453946.3 discloses a new method for reducing germanium content in lead slag by alkaline pre-leaching. By performing alkaline pre-leaching before the acidic leaching of zinc oxide dust, the germanium content in the lead slag is reduced, thereby increasing the germanium leaching rate. However, after alkaline pre-leaching, the process returns to acidic leaching, which requires a lot of resources to adjust the pH to acidic, thus increasing the difficulty of the process and the separation cost to some extent.

[0004] Therefore, it is necessary to provide a simple, economical, and efficient method for separating lead and germanium from zinc oxide leaching residue to overcome the above-mentioned defects. Summary of the Invention

[0005] To overcome the problems existing in the background technology, the present invention provides a method for separating lead and germanium from zinc oxide flue leaching residue. Utilizing the chemical principle that lead sulfate and zinc readily undergo a displacement reaction, the method for separating lead and germanium from zinc oxide flue leaching residue is simplified, separation costs are reduced, and separation efficiency is improved. Furthermore, the separated filtrate can be returned to the leaching process as a solvent, and the high-lead slag can be used as raw material for pyrometallurgical lead smelting. All separation products can be recycled and reused, saving resources. At the same time, due to the good separation effect, it also helps to improve the lead grade of the raw materials for pyrometallurgical lead smelting.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] The separation method includes the following steps:

[0008] (1) Add zinc oxide leaching residue to the reactor, and then add zinc powder to the reactor. The zinc powder and zinc oxide leaching residue undergo a displacement reaction.

[0009] (2) The reaction product in step (1) is subjected to pressure filtration, and after solid-liquid separation, the filtrate and the filter residue are obtained;

[0010] (3) Wash and pulp the filter residue from step (2);

[0011] (4) The washing and pulping product in step (3) is subjected to secondary pressure filtration, and after solid-liquid separation, secondary pressure filtrate and high lead slag are obtained.

[0012] Preferably, the zinc oxide fume leaching residue is obtained by the following steps:

[0013] Q1: Zinc oxide dust is wet ball-milled to obtain a dust slurry;

[0014] Q2: Add zinc-containing acid waste liquid to the reactor, and then add the flue dust slurry obtained in step Q1 to the reactor. Carry out the leaching reaction at a certain reaction temperature.

[0015] Q3: During the reaction in step Q2, zinc oxide dust is added to adjust the pH at the leaching endpoint. After leaching is completed, zinc oxide dust leaching residue is obtained.

[0016] The filtrate from steps (2) and (4) is returned to step Q2 as a leaching solvent for reuse.

[0017] Preferably, the main components of the zinc powder in step (1) include metallic zinc ≥85~82%, total zinc ≥87~90%, germanium ≤50g / t, chlorine ≤0.02~0.06%, lead 4%-0.5%, antimony 0.3%-0.02%, and arsenic ≤0.2%.

[0018] Preferably, the equipment used for pressure filtration and secondary pressure filtration in steps (2) and (4) is a plate and frame filter press.

[0019] Preferably, in step (3), production water is used to wash and pulp the filter press residue, and the liquid-to-solid ratio of production water to filter press residue is 3:1.

[0020] Preferably, in step Q1, the liquid-to-solid ratio of the liquid to zinc oxide dust in the wet ball milling slurry is 2-3:1.

[0021] Preferably, the zinc-containing acid waste liquid in step Q2 contains 80-100 g / L of zinc and 5-10 g / L of hydrogen ions.

[0022] Preferably, the reaction temperature in step Q2 is controlled at 80~85℃.

[0023] Preferably, the pH at the leaching endpoint in step Q3 is adjusted to 2.5.

[0024] Preferably, the zinc oxide leaching residue mainly comprises 25-40% lead, 5-8% zinc, and 300-450 g / t germanium, and the liquid-to-solid ratio of the zinc oxide leaching residue is 3:1.

[0025] In zinc oxide leaching residue, lead and germanium exist in a co-occurring form, with lead mainly existing in the form of lead sulfate. Based on the chemical properties of lead sulfate, it is known that it readily undergoes a displacement reaction with active metals such as zinc powder to generate lead. This principle can be used to separate lead and germanium in zinc oxide leaching residue. The reaction formula is: Zn + PbSO4 = Pb + ZnSO4.

[0026] The beneficial effects of this invention are:

[0027] 1. This invention uses a displacement reaction between zinc and lead sulfate to separate lead and germanium in zinc oxide leaching residue, simplifying the separation method, reducing separation costs, and improving separation efficiency.

[0028] 2. This invention returns the separated filtrate to the leaching stage as a solvent and uses the high-lead slag as a raw material for pyrometallurgical lead smelting, thereby realizing the recycling and reuse of the separated products, saving resources, and helping to improve the lead grade of the raw materials for pyrometallurgical lead smelting. Attached Figure Description

[0029] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and beneficial effects of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to facilitate understanding by those skilled in the art.

[0031] Example 1

[0032] Add zinc and acid waste liquid (Zn: 81 g / L, H) to the beaker. +200g of zinc oxide slurry (Pb: 17.28%, Zn: 55.19%, Ge: 832g / t, As: 0.40%, SiO2: 1.93%) after wet ball milling was weighed into a beaker and added to a 1L container. The mixture was heated to 80℃ and maintained at that temperature for 20 min. Then, zinc oxide slurry was added to adjust the pH to 2.5 at the leaching endpoint, and the mixture was reacted for another 30 min. Finally, 8g of zinc powder was weighed into the reactor and stirred evenly for 10 min. Liquid-solid separation was performed using a vacuum filtration flask. The filter residue was washed and slurried with 500mL of water, and then subjected to a second vacuum filtration. The composition of the filter residue was analyzed to be: Pb: 77.32%, Zn: 6.59%, Ge: 180g / t. The Pb content in the filter residue increased by approximately 60% compared to the Pb content in the zinc oxide slurry, while the Ge content decreased by approximately 650g / t.

[0033] Comparative Example 1

[0034] Add zinc and acid waste liquid (Zn: 81 g / L, H) to the beaker. + 200g of zinc oxide slurry (Pb: 17.28%, Zn: 55.19%, Ge: 832g / t, As: 0.40%, SiO2: 1.93%) after wet ball milling was weighed into a beaker and added to a volume of 1L. The mixture was heated to 80℃ and maintained at that temperature for 20 min. Then, zinc oxide slurry was added to adjust the pH to 2.5 at the leaching endpoint. After reacting for another 30 min, liquid-solid separation was performed using a vacuum filtration flask. The filter residue was washed and slurried with 500mL of water, followed by a second vacuum filtration. The composition of the filter residue after vacuum filtration was: Pb: 37.21%, Zn: 8.49%, Ge: 281g / t. The Pb content increased by approximately 20%, and the Ge content decreased by approximately 550g / t.

[0035] By comparing the filter residue composition results of Example 1 and Comparative Example 1, the Pb content in Example 1 was 77.32%, an increase of 60.04% compared to the Pb content in zinc oxide flue dust, and the Ge content was 180 g / t, a decrease of 650 g / t compared to the Ge content in zinc oxide flue dust. In contrast, the Pb content in Comparative Example 1 was 37.21%, an increase of only 19.93% compared to the Pb content in zinc oxide flue dust, and the Ge content was 281 g / t, a decrease of only 550 g / t compared to the Ge content in zinc oxide flue dust. This indicates that in Example 1, more Pb was converted into solids and remained in the filter residue, while in Comparative Example 1, less Pb was converted into solids and remained in the filter residue. Furthermore, in Example 1, more Ge remained in the filtrate, while in Comparative Example 1, less Ge remained in the filtrate. Clearly, after solid-liquid separation, the separation effect of Pb and Ge in Example 1 was better than that in Comparative Example 1.

[0036] Example 2

[0037] Add zinc and acid waste liquid (Zn: 81 g / L, H) to the beaker. + 200g of zinc oxide slurry (Pb: 18.05%, Zn: 55.93%, Ge: 1043g / t, As: 0.69%, SiO2: 1.13%) after wet ball milling was weighed into a beaker and added to a 1L container. The mixture was heated to 80℃ and maintained at that temperature for 20 min. Then, zinc oxide slurry was added to adjust the pH to 2.5 at the leaching endpoint, and the mixture was reacted for another 30 min. Finally, 8g of zinc powder was weighed into the reactor and stirred evenly for 10 min. Liquid-solid separation was performed using a vacuum filtration flask. The filter residue was washed and slurried with 500mL of water, and then subjected to a second vacuum filtration. The composition of the filter residue was analyzed to be: Pb: 78.86%, Zn: 7.89%, Ge: 256g / t. The Pb content in the filter residue increased by 60.81% compared to the Pb content in the zinc oxide slurry, while the Ge content decreased by approximately 790g / t.

[0038] Comparative Example 2

[0039] Add zinc and acid waste liquid (Zn: 81 g / L, H) to the beaker. + 200g of zinc oxide slurry (Pb: 18.05%, Zn: 55.93%, Ge: 1043g / t, As: 0.69%, SiO2: 1.13%) after wet ball milling was weighed into a beaker and added to a volume of 1L. The mixture was heated to 80℃ and maintained at that temperature for 20 min. Then, zinc oxide slurry was added to adjust the pH to 2.5 at the leaching endpoint, and the mixture was reacted for another 30 min. Liquid-solid separation was performed using a vacuum filtration flask. The filter residue was washed and slurried with 500mL of water, and then subjected to a second vacuum filtration. The composition of the filter residue after vacuum filtration was analyzed to be: Pb: 36.54%, Zn: 9.64%, Ge: 343g / t. The Pb content increased by approximately 18%, while the Ge content decreased by 700g / t.

[0040] By comparing the filter residue composition results of Example 2 and Comparative Example 2, the Pb content in Example 2 was 78.86%, an increase of 60.81% compared to the Pb content in zinc oxide flue dust, while the Ge content was 256 g / t, a decrease of 790 g / t compared to the Ge content in zinc oxide flue dust. In contrast, the Pb content in Comparative Example 2 was 36.54%, an increase of only 18.49% compared to the Pb content in zinc oxide flue dust, and the Ge content was 343 g / t, a decrease of only 700 g / t compared to the Ge content in zinc oxide flue dust. This indicates that in Example 2, more Pb was converted into solids and remained in the filter residue, while in Comparative Example 2, less Pb was converted into solids and remained in the filter residue. Furthermore, in Example 2, more Ge remained in the filtrate, while in Comparative Example 2, less Ge remained in the filtrate. Clearly, after solid-liquid separation, the separation effect of Pb and Ge in Example 2 was better than that in Comparative Example 2.

[0041] Example 3

[0042] Add zinc and acid waste liquid (Zn: 81 g / L, H) to the beaker. + 200g of zinc oxide slurry (Pb: 19.38%, Zn: 52.62%, Ge: 819g / t, As: 0.67%, SiO2: 2.20%) after wet ball milling was weighed into a beaker and added to a 1L container. The mixture was heated to 80℃ and maintained at that temperature for 20 min. Then, zinc oxide slurry was added to adjust the pH to 2.5 at the leaching endpoint, and the mixture was reacted for another 30 min. Finally, 8g of zinc powder was weighed into the reactor and stirred evenly for 10 min. Liquid-solid separation was performed using a vacuum filtration flask. The filter residue was washed and slurried with 500mL of water, and then subjected to a second vacuum filtration. The composition of the filter residue was analyzed to be: Pb: 75.66%, Zn: 7.62%, Ge: 197g / t. The Pb content in the filter residue increased by approximately 56% compared to the Pb content in the zinc oxide slurry, while the Ge content decreased by approximately 600g / t.

[0043] Comparative Example 3

[0044] Add zinc and acid waste liquid (Zn: 81 g / L, H) to the beaker. + 200g of zinc oxide slurry (Pb: 19.38%, Zn: 52.62%, Ge: 819g / t, As: 0.67%, SiO2: 2.20%) after wet ball milling was weighed into a beaker and added to a volume of 1L. The mixture was heated to 80℃ and maintained at that temperature for 20 min. Zinc oxide slurry was then added to adjust the leaching endpoint pH to 2.5, and the mixture was reacted for another 30 min. Liquid-solid separation was then performed using a vacuum filtration flask. The filter residue was washed and slurried with 500mL of water, followed by a second vacuum filtration. All other steps and experimental parameters were the same as in Example 3. Analysis of the filter residue after filtration revealed the following composition: Pb: 38.65%, Zn: 7.84%, Ge: 268g / t. The Pb content increased by approximately 20%, while the Ge content decreased by approximately 550g / t.

[0045] By comparing the filter residue composition results of Example 3 and Comparative Example 3, the Pb content in Example 3 was 75.66%, an increase of 56.28% compared to the Pb content in zinc oxide flue dust, and the Ge content was 197 g / t, a decrease of 622 g / t compared to the Ge content in zinc oxide flue dust. In contrast, the Pb content in Comparative Example 3 was 38.65%, an increase of only 19.27% ​​compared to the Pb content in zinc oxide flue dust, and the Ge content was 268 g / t, a decrease of only 551 g / t compared to the Ge content in zinc oxide flue dust. This indicates that in Example 3, more Pb was converted into solids and remained in the filter residue, while in Comparative Example 3, less Pb was converted into solids and remained in the filter residue. Furthermore, in Example 3, more Ge remained in the filtrate, while in Comparative Example 3, less Ge remained in the filtrate. Clearly, after solid-liquid separation, the separation effect of Pb and Ge in Example 3 was better than that in Comparative Example 3.

[0046] By comparing the results of the filter residue composition analysis of Examples 1, 2, and 3 longitudinally, it was found that the filter residue of Example 2 showed the largest increase in Pb content and the largest decrease in Ge content. Therefore, it can be concluded that the separation conditions in Example 2 were the optimal conditions.

[0047] 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 method for separating lead and germanium from zinc oxide leaching residue, characterized in that: The separation method includes the following steps: (1) Add zinc oxide leaching residue containing lead sulfate to the reactor, and then add zinc powder to the reactor. The zinc powder and zinc oxide leaching residue undergo a displacement reaction. (2) The reaction product in step (1) is subjected to pressure filtration, and after solid-liquid separation, the filtrate and the filter residue are obtained; (3) Wash and pulp the filter residue from step (2); (4) The washing and pulping product in step (3) is subjected to secondary pressure filtration, and after solid-liquid separation, secondary pressure filtrate and high lead slag are obtained.

2. The method for separating lead and germanium from zinc oxide leaching residue according to claim 1, characterized in that: The zinc oxide fume leaching residue is obtained by the following steps: Q1: Zinc oxide dust is wet ball-milled to obtain a dust slurry; Q2: Add zinc-containing acid waste liquid to the reactor, then add the flue dust slurry obtained in step Q1 to the reactor, and carry out the leaching reaction at 80~85℃; Q3: During the reaction in step Q2, zinc oxide dust is added to adjust the pH at the leaching endpoint. After leaching is completed, zinc oxide dust leaching residue is obtained. The filtrate from steps (2) and (4) is returned to step Q2 as a leaching solvent for reuse.

3. The method for separating lead and germanium from zinc oxide leaching residue according to claim 1, characterized in that: The equipment used for pressure filtration and secondary pressure filtration in steps (2) and (4) is a plate and frame filter press.

4. The method for separating lead and germanium from zinc oxide leaching residue according to claim 1, characterized in that: In step (3), production water is used to wash and pulp the filter press residue, and the liquid-to-solid ratio of production water to filter press residue is 3:

1.

5. The method for separating lead and germanium from zinc oxide leaching residue according to claim 2, characterized in that: In step Q1, the liquid-to-solid ratio of the liquid to the zinc oxide dust in the wet ball milling slurry is 2-3:

1.

6. The method for separating lead and germanium from zinc oxide leaching residue according to claim 2, characterized in that: The zinc-containing acid waste liquid in step Q2 contains 80-100 g / L of zinc and 5-10 g / L of hydrogen ions.

7. The method for separating lead and germanium from zinc oxide leaching residue according to claim 2, characterized in that: In step Q3, the pH at the leaching endpoint is adjusted to 2.

5.

8. A method for separating lead and germanium from zinc oxide leaching residue according to any one of claims 1-7, characterized in that: The zinc oxide leaching residue comprises 25%-40% lead, 5%-8% zinc, and 300-450 g / t germanium.

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