Efficient recovery method of valuable metals in copper smelting white ash

Abstract

The application provides a method for efficiently recovering valuable metals in copper smelting white ash, and belongs to the technical field of non-ferrous metallurgy and comprehensive utilization of secondary resources. The method realizes efficient extraction of copper, zinc, bismuth, indium, germanium and other valuable metals through key steps of raw material pretreatment, oxygen pressure leaching and copper replacement precipitation in sequence, and simultaneously completes the stabilization and solidification of harmful elements such as arsenic. The leaching is carried out in a high-pressure oxygen-rich environment, which significantly improves the metal leaching efficiency and selectivity, wherein the copper leaching rate is not less than 93%, the zinc leaching rate is not less than 98%, the bismuth recovery rate is more than 90%, the arsenic solidification rate is more than 99%, and the overall slag rate is controlled within 70%. The method has the advantages of short process, stable operation, good environmental compatibility, and can adapt to different compositions of copper smelting white ash raw materials, and has obvious resource recovery benefits and industrial application potential.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization of metallurgical resources and relates to a method for comprehensive recovery of valuable metals from copper smelting white smoke ash. Background Technology

[0002] The white ash produced during copper smelting contains various valuable metals and harmful elements such as copper, zinc, bismuth, and arsenic. Traditional treatment methods mainly involve stockpiling or simple recycling, which not only leads to the loss of valuable metal resources but also poses a continuous threat to the environment due to the potential leaching of heavy metals. Currently, conventional acid or alkaline leaching processes for treating this type of material generally suffer from low metal recovery rates, difficulty in stabilizing and solidifying arsenic, and high wastewater treatment costs. Oxygen pressure leaching technology, with its highly efficient reaction characteristics under high temperature and pressure conditions and its advantage of converting arsenic into a stable slag phase, has become a key research direction for treating complex high-arsenic materials. However, the oxygen pressure leaching system for copper smelting white ash is still not perfect, especially in areas such as multi-metal synergistic leaching, efficient arsenic stabilization, and optimization of the overall process economic benefits, where there is still considerable room for improvement. Summary of the Invention

[0003] The purpose of this invention is to provide a method for the efficient recovery of valuable metals from copper smelting fly ash, overcoming the technical problems of low metal recovery rate, low resource utilization rate, and environmental pollution caused by arsenic-containing materials in traditional recovery processes. By optimizing process conditions, the recovery efficiency of valuable metals is further improved, thereby achieving the tiered and efficient recovery of valuable metals such as copper, zinc, lead, silver, bismuth, indium, and germanium from fly ash, while simultaneously completing the harmless treatment of arsenic, thus achieving both good environmental and economic benefits.

[0004] To achieve its purpose, the present invention adopts the following technical solution: This invention provides a method for efficient recovery of valuable metals from copper smelting white flue dust, comprising the following steps: (1) Pretreatment: After removing impurities from the white smoke ash from copper smelting, the ash is sieved, ball-milled to a particle size ≤200 mesh, and thoroughly mixed. (2) Oxygen pressure leaching: The pretreated white smoke ash is added to sulfuric acid solution at a liquid-solid mass ratio of 4 to 6:1 and mixed. Then, ferrous sulfate is added at a Fe / As molar ratio of 1.2, and 5g of sodium lignosulfonate is added as a reaction aid. The mixture is mixed evenly to obtain a mixed slurry. The mixed slurry is transferred to a high-temperature oxygen pressure vessel, oxygen is introduced to maintain the system pressure at 1.6 to 2.0 MPa, the temperature is raised to 150 to 180°C, and the reaction is carried out in a high-pressure oxygen-rich environment for 120 to 180 min. (3) Solid-liquid separation: After the reaction is completed, the temperature is reduced and the pressure is released. The mixture is filtered to obtain the leachate and the leach residue. Zinc and copper enter the leachate in the form of zinc sulfate and copper sulfate, respectively. The leach residue is dried at 100°C, weighed, and the content of lead, silver, bismuth and arsenic enriched in it is detected. (4) Displacement copper precipitation: Iron powder is added to the leaching solution (the amount of iron powder to be added is calculated according to the copper content in the leaching solution) to carry out the displacement reaction, the pH is adjusted to 2.0, the temperature is controlled at 75℃, and the reaction is carried out for 60 minutes; after the reaction is completed, the sponge copper is obtained by filtration and returned to the copper smelting system, and the filtrate is sent to the indium and germanium system to recover indium and germanium.

[0005] As a further preferred embodiment of the technical solution of the present invention, in step (2), the concentration of the sulfuric acid solution is 60 g / L. The sulfuric acid used to prepare the sulfuric acid solution is industrial 98% sulfuric acid, which is a by-product of the enterprise's acid production process and does not need to be purchased commercially.

[0006] Furthermore, in step (4), the amount of iron powder added is 2.0 times the theoretically required amount.

[0007] Further, in step (4), the pH of the leachate is adjusted to 2.0 using sodium hydroxide solution.

[0008] Furthermore, in step (4), the temperature required for the copper displacement reaction is provided by a constant-temperature heating plate.

[0009] Furthermore, the main components of the copper smelting white smoke ash are shown in Table 1.

[0010] Table 1. Main components (%) of white flue dust obtained from copper smelting This invention comprehensively recovers valuable metals from copper smelting fly ash, ultimately achieving the following indicators: copper leaching rate of no less than 93%, zinc leaching rate of no less than 98%, bismuth recovery rate exceeding 90%, arsenic solidification rate exceeding 99%, and overall slag rate controlled below 70%, significantly improving the leaching and recovery efficiency of each valuable metal. Calculations indicate that this method can generate an annual revenue of approximately 15 million yuan.

[0011] Specifically, the beneficial effects of the method of the present invention include: 1. High leaching efficiency, effectively improving the leaching rate of major valuable metals such as copper and zinc, achieving full resource recovery, and significant economic benefits.

[0012] 2. It has strong comprehensive metal recycling capabilities, and can achieve efficient tiered recycling of various valuable metals such as lead, silver, bismuth, indium, and germanium while recycling copper and zinc.

[0013] 3. The process has lower energy consumption and has energy-saving advantages in the oxygen pressure leaching stage compared with some traditional processes.

[0014] 4. Environmentally friendly: By controlling the conditions during the copper replacement process, valuable metal precipitation is promoted, wastewater and waste residue discharge is reduced, environmental pollution is reduced, and environmental protection requirements are met.

[0015] 5. It has strong raw material adaptability and can adapt to copper smelting white smoke ash with different compositions and properties. Process parameters can be flexibly adjusted and optimized according to specific raw materials.

[0016] 6. The operation is simple and reliable, the overall process is easy to implement, which helps to reduce production costs, improve economic efficiency and competitiveness, and is suitable for large-scale industrial applications. Attached Figure Description

[0017] Figure 1 A schematic flowchart illustrating the efficient and comprehensive recovery of valuable metals from white smoke ash in copper smelting. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] In the following embodiments of the present invention, copper smelting white flue dust is subjected to pretreatment including impurity removal, sieving, ball milling, and mixing. The particle size of the pretreated copper smelting white flue dust is 200 mesh.

[0020] Example 1 In this Example 1, the composition and content of copper smelting white smoke ash are shown in Table 2.

[0021] Table 2. Content (%) of main components in copper smelting white smoke ash from Example 1 350g of pretreated copper smelting white smoke ash was weighed and thoroughly mixed with a 60g / L sulfuric acid solution at a liquid-to-solid mass ratio of 4:1. Then, 78.23g of ferrous sulfate and 5g of sodium lignosulfonate were added and mixed evenly to obtain a slurry. The slurry was slowly added to a high-temperature oxygen pressure reactor, with the oxygen partial pressure controlled at 1.6MPa and the reaction temperature controlled at 150℃ for 120min. After the reaction, the temperature was lowered and the pressure was released, followed by filtration to obtain a leaching solution and leaching residue. Zinc and copper entered the leaching solution as zinc sulfate and copper sulfate, respectively. The leaching residue was dried at 100℃, weighed, and the content of enriched lead, silver, bismuth, and arsenic was determined.

[0022] The slag rate was 68.63%, the zinc leaching rate was 98.69%, the copper leaching rate was 93.06%, the bismuth recovery rate was 91.25%, and the arsenic solidification rate was 99.28%.

[0023] The leachate was mixed with twice the theoretical amount of iron powder for a displacement reaction. The pH was adjusted to 2.0 using sodium hydroxide solution, and the temperature was controlled at 75°C for 60 minutes. After the reaction, the mixture was filtered to obtain sponge copper, which was returned to the copper smelting system with a copper grade of 78.27%. The filtrate was sent to the indium-germanium system to recover indium and germanium.

[0024] Example 2 In this Example 2, the composition and content of copper smelting white smoke ash are shown in Table 3.

[0025] Table 3. Content (%) of main components in copper smelting white smoke ash from Example 2 350g of pretreated copper smelting white ash was weighed and thoroughly mixed with a 60g / L sulfuric acid solution at a liquid-to-solid mass ratio of 5:1. Then, 78.23g of ferrous sulfate and 5g of sodium lignosulfonate were added and mixed evenly to obtain a slurry. The slurry was slowly added to a high-temperature oxygen pressure reactor, with the oxygen partial pressure controlled at 1.8MPa and the reaction temperature controlled at 170℃ for 160min. After the reaction, the temperature was lowered and the pressure was released, followed by filtration to obtain a leaching solution and leaching residue. Zinc and copper entered the leaching solution as zinc sulfate and copper sulfate, respectively. The leaching residue was dried at 100℃, weighed, and the content of enriched lead, silver, bismuth, and arsenic was determined.

[0026] The slag rate was 67.65%, the zinc leaching rate was 98.17%, the copper leaching rate was 94.25%, the bismuth recovery rate was 91.89%, and the arsenic solidification rate was 99.35%.

[0027] The leachate was mixed with twice the theoretical amount of iron powder for a displacement reaction. The pH was adjusted to 2.0 using sodium hydroxide solution, and the temperature was controlled at 75°C for 60 minutes. After the reaction, the mixture was filtered to obtain sponge copper, which was returned to the copper smelting system with a copper grade of 79.36%. The filtrate was sent to the indium-germanium system to recover indium and germanium.

[0028] Example 3 In this Example 3, the composition and content of copper smelting white smoke ash are shown in Table 4.

[0029] Table 4. Content (%) of main components in copper smelting white smoke ash from Example 3 350g of pretreated copper smelting white ash was weighed and thoroughly mixed with a 60g / L sulfuric acid solution at a liquid-to-solid mass ratio of 6:1. Then, 78.23g of ferrous sulfate and 5g of sodium lignosulfonate were added and mixed evenly to obtain a slurry. The slurry was slowly added to a high-temperature oxygen pressure reactor, with the oxygen partial pressure controlled at 2.0MPa and the reaction temperature controlled at 180℃ for 180min. After the reaction, the temperature was lowered and the pressure was released, followed by filtration to obtain a leaching solution and leaching residue. Zinc and copper entered the leaching solution as zinc sulfate and copper sulfate, respectively. The leaching residue was dried at 100℃, weighed, and the content of enriched lead, silver, bismuth, and arsenic was determined.

[0030] The slag rate was 69.98%, the zinc leaching rate was 98.43%, the copper leaching rate was 94.98%, the bismuth recovery rate was 92.57%, and the arsenic solidification rate was 99.67%.

[0031] The leachate was mixed with twice the theoretical amount of iron powder for a displacement reaction. The pH was adjusted to 2.0 using sodium hydroxide solution, and the temperature was controlled at 75°C for 60 minutes. After the reaction, the mixture was filtered to obtain sponge copper, which was returned to the copper smelting system with a copper grade of 80.15%. The filtrate was sent to the indium-germanium system to recover indium and germanium.

Claims

1. A method for efficient recovery of valuable metals from copper smelting white flue dust, characterized in that, Includes the following steps: (1) Pretreatment: The white smoke ash from copper smelting is sieved, ball-milled to a particle size ≤200 mesh, and thoroughly mixed; (2) Oxygen pressure leaching: The pretreated white smoke ash is added to sulfuric acid solution at a liquid-solid mass ratio of 4 to 6:1 and mixed. Then, ferrous sulfate is added at a Fe / As molar ratio of 1.2, and 5g of sodium lignosulfonate is added as a reaction aid. The mixture is mixed evenly to obtain a mixed slurry. The mixed slurry is transferred to a high-temperature oxygen pressure vessel, oxygen is introduced to maintain the system pressure at 1.6 to 2.0 MPa, the temperature is raised to 150 to 180°C, and the reaction is carried out in a high-pressure oxygen-rich environment for 120 to 180 min. (3) Solid-liquid separation: After the reaction is completed, the temperature is reduced and the pressure is released. The mixture is filtered to obtain the leachate and the leach residue. Zinc and copper enter the leachate in the form of zinc sulfate and copper sulfate, respectively. The leach residue is dried at 100°C, weighed, and the content of lead, silver, bismuth and arsenic enriched in it is detected. (4) Displacement copper: Iron powder is added to the leaching solution to carry out the displacement reaction, the pH is adjusted to 2.0, the temperature is controlled at 75℃, and the reaction is carried out for 60 minutes. After the reaction is completed, the sponge copper is obtained by filtration and returned to the copper smelting system. The filtrate is sent to the indium and germanium system to recover indium and germanium.

2. The method for efficient recovery of valuable metals from copper smelting white flue dust according to claim 1, characterized in that, In step (2), the concentration of sulfuric acid solution is 60 g / L.

3. The method for efficient recovery of valuable metals from copper smelting white flue dust according to claim 1, characterized in that, In step (4), the amount of iron powder added is 2.0 times the theoretically required amount.

4. The method for efficient recovery of valuable metals from copper smelting white flue dust according to claim 3, characterized in that, In step (4), the pH of the leachate is adjusted to 2.0 using sodium hydroxide solution.

5. The method for efficient recovery of valuable metals from copper smelting white flue dust according to claim 3, characterized in that, In step (4), the temperature required for the copper displacement reaction is provided by a constant temperature heating plate.

6. A method for efficient recovery of valuable metals from copper smelting fume ash according to any one of claims 1-5, characterized in that, The main components of the white smoke ash from copper smelting are as follows: Zn 3.45~4.56%, Pb 25.21~29.45%, Cu 12.64~16.79%, Fe 0.35~1.27%, As 2.21~6.05%, Ag 0.02~0.05%, In 0.008~0.016%, Sb 0.2~0.58%, Bi 8.35~11.28%, Cd 0.5~1.2%.

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