Method for recycling copper from waste paint residue

Abstract

The present application relates to a kind of copper in waste paint residue resource recovery method, belong to solid waste resource processing technical field.The method is as follows: waste paint residue is broken and ground;In inorganic salt culture medium, biological leaching bacterial strain is obtained by shaking table culture biological leaching liquor;When biological leaching liquor pH drops to 0.6-1.4, according to 2% to 10% solid-liquid ratio, paint residue powder is input, and shaking table culture is carried out until the dissolution concentration of copper ion no longer increases, and biological leaching ends.Biological leaching liquor is extracted in the extractant formed by LIX984 and sulfonated kerosene DT100, and the oil phase and water phase enriched in copper are separated;The oil phase is back-extracted with sulfuric acid solution, and the water phase and oil phase enriched in copper are separated;Water phase is evaporated and cooled to crystallize and obtain copper sulfate crystal.This method recycles copper ions in waste paint residue, with the characteristics of high recovery rate, simple process, energy saving and environmental protection.

Description

Technical Field

[0001] This invention relates to a method for the resource recovery of copper from waste paint residue, belonging to the field of solid waste resource treatment technology. Background Technology

[0002] Paint waste is solid waste generated during the coating process. In manual spraying, 40%–60% of the paint mist is oversprayed and dispersed, while electrostatic spraying produces over 10%. This overspray condenses and settles to form paint waste. Paint waste mainly consists of resin, pigments, additives, and moisture and flocculants mixed in during collection. It is classified as hazardous solid waste, primarily due to its toxicity and flammability. Human contact with paint waste can cause symptoms such as dizziness, headache, drowsiness, weakness, and chest tightness. It may also affect the digestive system, causing loss of appetite and nausea. In severe cases, it can damage the liver and hematopoietic system, and even lead to death.

[0003] In China, the main methods for treating paint waste are landfill and incineration. Landfill involves simple treatment or solidification of the paint waste before burying it underground with appropriate isolation measures. It has advantages such as low cost, large processing capacity, and high final disposal efficiency, making it the preferred method for early paint waste treatment. Incineration has also been vigorously developed due to its advantages of volume reduction, harmlessness, resource recovery, and simple operation. However, landfill requires a large area and easily causes groundwater and soil pollution, while incineration inevitably poses secondary pollution problems. Paint waste is harmful when discarded, but valuable when utilized. Given my country's large population, weak industrial base, and tight energy supply, improving the comprehensive utilization efficiency of paint waste can not only save resources and turn waste into treasure, but also improve the environment and reduce the huge economic losses caused by secondary pollution. Currently, paint waste is mainly utilized through recycling, reuse, and the preparation of functional materials. However, comprehensive utilization technologies place high demands on the physical properties of the paint waste. If the molecular structure of the paint waste has been completely destroyed, becoming extremely brittle and unable to re-adhere under the action of solvents, then such paint waste cannot be reused. Therefore, for paint waste with severely damaged physical properties, choosing a suitable method to turn waste into treasure is crucial in the comprehensive utilization of paint waste.

[0004] Current research on waste paint residue treatment focuses primarily on the treatment of organic matter, with limited research on the recovery and treatment of metals within the waste paint residue. If suitable methods can be selected to recover valuable metal ions from waste paint residue, its resource utilization can be achieved. Pyrometallurgy and hydrometallurgy are traditional methods for metal recovery. Pyrometallurgy involves high-temperature treatment of waste materials...

[0005] Pyrometallurgy alters the physical and chemical state of metals, extracting them through high-temperature chemical reactions. This process includes calcination, roasting, smelting, and refining. While pyrometallurgy has been used for many years, it suffers from poor selectivity, high energy consumption, low metal recovery rates, and demanding equipment requirements, leading to a series of environmental problems. Hydrometallurgy mainly involves two processes: dissolving and leaching metals from solid waste, and subsequent separation, extraction, and purification of the metals. Hydrometallurgy is the mainstream process for recovering metals from spent catalysts; however, it consumes large amounts of hazardous chemicals such as strong acids, strong alkalis, and oxidants. This places high demands on equipment materials and operating conditions, and increasingly stringent regulations on hazardous chemicals in recent years have limited the application and promotion of traditional hydrometallurgical processes.

[0006] Over the past few decades, biometallurgy has emerged as one of the most promising metal recovery technologies. Bioleaching refers to the process by which microorganisms, through direct action or the indirect action of their metabolites, dissolve target metals in solid materials; this process is also known as bioleaching or biohydrometallurgy. Compared with traditional hydrometallurgy, biometallurgy offers advantages such as low cost, environmental friendliness, and high metal recovery rates. This invention utilizes bioleaching of copper ions from waste paint sludge, employing extraction and back-extraction to recover copper ions from the leachate and prepare copper sulfate crystals. This method efficiently recovers valuable metal ions from waste paint sludge and yields high-value-added products, providing a new approach to the recycling and utilization of waste paint sludge. Summary of the Invention

[0007] To address the limited research on metal recovery from waste paint sludge, this invention aims to recover copper from copper-containing waste paint sludge through resource utilization. It proposes a method for recovering copper from waste paint sludge using bioleaching, and utilizing extraction and back-extraction to remove impurity ions from the leachate, recovering target copper ions to prepare copper sulfate crystals. This objective is achieved through the following technical solution.

[0008] This invention discloses a method for the resource recovery of copper from waste paint residue, the specific steps of which are as follows:

[0009] (1) Place the copper-containing waste paint residue in an electric heating constant temperature drying oven at 80°C and dry it to constant weight. Then crush and grind it, and sieve it through a 200-mesh sieve for later use.

[0010] (2) Inoculate the bioleaching strain into an inorganic salt culture medium, place it in a shaker and monitor its pH and ORP changes, add the paint residue powder obtained in step (1), continue to culture in a shaker for bioleaching until the concentration of copper ions in the leachate no longer increases, and collect the leachate by centrifugation or filtration.

[0011] The inorganic salt culture medium consists of 2.0 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4·7H2O, 0.25 g / L anhydrous CaCl2, and 8–16 g / L reducing energy substrate, with water as the solvent; the reducing energy substrate is sulfur or pyrite or a mixture of sulfur and pyrite.

[0012] The bioleaching strains are autotrophic bacteria, including Thiobacillus thiooxidans, Thiobacillus ferrooxidans, and Leptospira hemiphila. When the energy substrate is sulfur, Thiobacillus thiooxidans is inoculated; when the energy substrate is pyrite, Thiobacillus ferrooxidans and Leptospira hemiphila are inoculated separately; when the energy substrate is sulfur and pyrite, a mixture of Thiobacillus thiooxidans, Thiobacillus ferrooxidans, and Leptospira hemiphila is inoculated.

[0013] (3) Adjust the pH of the leachate obtained in step (2) with 1 mol / L sodium carbonate solution, mix it with the extractant composed of LIX984 and sulfonated kerosene DT100, shake for 10 min to extract, and let it stand to separate into layers;

[0014] (4) The oil phase obtained in step (3) is back-extracted with sulfuric acid solution, shaken for 10 min, and allowed to stand to separate into layers;

[0015] (5) Evaporate and cool the aqueous phase obtained in step (4) to obtain copper sulfate crystals.

[0016] The inoculation concentration of the aforementioned Thiobacillus thiooxidans, Thiobacillus ferrooxidans, and Leptospira ferrophila is 5%–15% (v / v);

[0017] During the cultivation of the leaching strain, its pH and ORP changes were monitored daily. When the pH dropped to 0.6-1.4, 2-10% (w / v) of waste paint residue powder was added, i.e., a solid-liquid ratio of 2-10%.

[0018] The conditions for the biological leachate shaker culture are 25–45°C and 100–180 rpm.

[0019] The pH of the leachate was adjusted to 1.0-4.0 using a 1 mol / L sodium carbonate solution;

[0020] The extractant consists of LIX984 and sulfonated kerosene DT100, 10-30% (LIX984:DT100, v / v); the stripping agent is a 50-300 g / L sulfuric acid solution.

[0021] The volume ratio of the extracted organic phase to the aqueous phase is 1:1 to 5:1, and the volume ratio of the back-extracted organic phase to the aqueous phase is 3:1 to 1:3.

[0022] The organic phase obtained by back-extraction regains its extraction capacity and can be reused in step (3) to extract copper;

[0023] Beneficial effects

[0024] This invention discloses a method for the resource-based recovery of copper from waste paint sludge. The feasibility of bioleaching copper-containing waste paint sludge was studied, and optimized conditions were established, achieving a leaching rate of 99.34%. Copper ions were separated from the leachate through extraction and back-extraction, and relevant parameters were optimized, resulting in an extraction rate of 99.46% and a back-extraction rate of 95.32%. The prepared copper sulfate crystals exhibited high purity and good crystallinity. This invention achieves the resource-based treatment of waste paint sludge, yielding high-value-added products and providing a new approach for the recycling and utilization of waste paint sludge. Attached Figure Description

[0025] Figure 1 X-ray diffraction (XRD) pattern of copper sulfate crystals in Example 1. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0027] Example 1

[0028] (1) Place copper-containing waste paint residue in an electric heating constant temperature drying oven and dry it at 80°C until constant weight. Then crush and grind it, and sieve it through a 200-mesh sieve for later use to obtain powder with a particle size of 0.074 mm.

[0029] (2) Preparation of bioleaching medium: The solutes are 2.0 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4·7H2O, 0.25 g / L anhydrous CaCl2 and 16 g / L reducing energy substrate, and the solvent is distilled water; wherein, the reducing energy substrate is a mixture of 8 g / L sulfur and 8 g / L pyrite; dispensed into 250 mL Erlenmeyer flasks at 100 mL / bottle; a mixed seed culture of 5% (v / v) Thiobacillus thiooxidans, 5% (v / v) Thiobacillus ferrooxidans and 5% (v / v) Leptospira ironophila was inoculated into the above medium to obtain bioleaching solution, and cultured in a shaker at 35℃ and 135 rpm, and its pH and ORP changes were monitored;

[0030] After 10 days of shaking culture, when the pH of the bioleaching medium dropped to 0.8, 6g (solid-liquid ratio 6%) of the paint residue powder obtained in step (1) was added, and the culture was continued in a shaking incubator (35℃, 135rpm) for bioleaching. Samples were taken every 2 days, and the samples were centrifuged at 8000rpm for 10min to obtain the supernatant. The concentration of copper ions dissolved in the supernatant was measured. After 9 days of bioleaching, the concentration of copper ions dissolved no longer increased, and the leaching was completed. The leachate was collected by centrifugation or filtration. The copper ion dissolution rate was 92.08%.

[0031] (3) Adjust the pH of the leachate obtained in step (2) to 2.0 with 1 mol / L sodium carbonate solution, mix it with the extractant composed of LIX984 and sulfonated kerosene DT100 (LIX984:DT100 = 10%) at a volume ratio of 1 / 3, shake for 10 min for extraction, let it stand to separate the layers, the upper phase is the copper-enriched oil phase and the lower phase is the aqueous phase, separate the copper-enriched oil phase and the aqueous phase; take the lower aqueous phase to determine the copper concentration, and calculate the extraction rate as 99.46%;

[0032] (4) The oil phase obtained in step (3) was mixed with 200 g / L sulfuric acid solution at a volume ratio of 1 / 1, shaken for 10 min for back extraction, allowed to stand and separate into layers, and the lower aqueous phase was taken to determine the copper concentration. The back extraction rate was calculated to be 95.33%.

[0033] The organic phase obtained by back-extraction regains its extraction capacity and can be reused in step (3) to extract copper;

[0034] (5) Evaporate and cool the aqueous phase obtained in step (4) to obtain copper sulfate crystals. Perform XRD analysis. Figure 1 The narrow peaks in the figure indicate that the generated copper sulfate has good crystallinity.

[0035] Example 2

[0036] (1) Place copper-containing waste paint residue in an electric heating constant temperature drying oven and dry it at 80°C until constant weight. Then crush and grind it, and sieve it through a 200-mesh sieve for later use to obtain powder with a particle size of 0.074 mm.

[0037] (2) Preparation of bioleaching medium: The solutes are 2.0 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4·7H2O, 0.25 g / L anhydrous CaCl2 and 16 g / L reducing energy substrate, and the solvent is distilled water; wherein, the reducing energy substrate is a mixture of 8 g / L sulfur and 8 g / L pyrite; dispensed into 250 mL Erlenmeyer flasks at 100 mL / bottle; a mixed seed culture of 5% (v / v) Thiobacillus thiooxidans, 5% (v / v) Thiobacillus ferrooxidans and 5% (v / v) Leptospira ironophila was inoculated into the above medium to obtain bioleaching solution, and cultured in a shaker at 35℃ and 135 rpm, and its pH and ORP changes were monitored;

[0038] After 10 days of shaking culture, when the pH of the bioleaching medium dropped to 1.0, 2g (solid-liquid ratio 2%) of the paint residue powder obtained in step (1) was added, and the culture was continued in a shaking incubator (35℃, 135rpm) for bioleaching. Samples were taken every 2 days, and the samples were centrifuged at 8000rpm for 10min to obtain the supernatant. The concentration of copper ions dissolved in the supernatant was measured. After 9 days of bioleaching, the concentration of copper ions dissolved no longer increased, and the leaching was completed. The leachate was collected by centrifugation or filtration. The copper ion dissolution rate was 99.34%.

[0039] (3) Adjust the pH of the leachate obtained in step (2) to 2.0 with 1 mol / L sodium carbonate solution, mix it with the extractant composed of LIX984 and sulfonated kerosene DT100 (LIX984:DT100 = 10%) at a volume ratio of 1 / 3, shake for 10 min for extraction, let it stand to separate the layers, the upper phase is the copper-enriched oil phase and the lower phase is the aqueous phase, separate the copper-enriched oil phase and the aqueous phase; take the lower aqueous phase to determine the copper concentration, and calculate the extraction rate as 99.46%;

[0040] (4) The oil phase obtained in step (3) was mixed with 200 g / L sulfuric acid solution at a volume ratio of 1 / 1, shaken for 10 min for back extraction, allowed to stand and separate into layers, and the lower aqueous phase was taken to determine the copper concentration. The back extraction rate was calculated to be 95.33%.

[0041] The organic phase obtained by back-extraction regains its extraction capacity and can be reused in step (3) to extract copper;

[0042] (5) Evaporate and cool the aqueous phase obtained in step (4) to obtain copper sulfate crystals.

[0043] Example 3

[0044] (1) Place copper-containing waste paint residue in an electric heating constant temperature drying oven and dry it at 80°C until constant weight. Then crush and grind it, and sieve it through a 200-mesh sieve for later use to obtain powder with a particle size of 0.074 mm.

[0045] (2) Preparation of bioleaching medium: the solute is 2.0 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4·7H2O, 0.25 g / L anhydrous CaCl2 and 16 g / L reducing energy substrate, and the solvent is distilled water; wherein, the reducing energy substrate is 16 g / L pyrite; dispensed into 250 mL Erlenmeyer flasks at 100 mL / bottle; inoculated the above medium with 15% (v / v) seed culture of Leptospira ironophila to obtain bioleaching solution, and cultured in a shaker at 35℃ and 135 rpm, and monitored its pH and ORP changes;

[0046] After 10 days of shaking culture, when the pH of the bioleaching medium dropped to 1.5, 4g (solid-liquid ratio 4%) of the paint residue powder obtained in step (1) was added, and the culture was continued in a shaking incubator (40℃, 135rpm) for bioleaching. Samples were taken every 2 days, and the samples were centrifuged at 8000rpm for 10min to obtain the supernatant. The concentration of copper ions dissolved in the supernatant was measured. After 9 days of bioleaching, the concentration of copper ions dissolved no longer increased, and the leaching was completed. The leachate was collected by centrifugation or filtration. The copper ion dissolution rate was 89.14%.

[0047] (3) Adjust the pH of the leachate obtained in step (2) to 2.0 with 1 mol / L sodium carbonate solution, mix it with the extractant composed of LIX984 and sulfonated kerosene DT100 (LIX984:DT100 = 10%) at a volume ratio of 1 / 3, shake for 10 min for extraction, let it stand to separate the layers, the upper phase is the copper-enriched oil phase and the lower phase is the aqueous phase, separate the copper-enriched oil phase and the aqueous phase; take the lower aqueous phase to determine the copper concentration, and calculate the extraction rate as 99.46%;

[0048] (4) The oil phase obtained in step (3) was mixed with 200 g / L sulfuric acid solution at a volume ratio of 1 / 1, shaken for 10 min for back extraction, allowed to stand and separate into layers, and the lower aqueous phase was taken to determine the copper concentration. The back extraction rate was calculated to be 95.33%.

[0049] The organic phase obtained by back-extraction regains its extraction capacity and can be reused in step (3) to extract copper;

[0050] (5) Evaporate and cool the aqueous phase obtained in step (4) to obtain copper sulfate crystals.

[0051] Example 4

[0052] (1) Place copper-containing waste paint residue in an electric heating constant temperature drying oven and dry it at 80°C until constant weight. Then crush and grind it, and sieve it through a 200-mesh sieve for later use to obtain powder with a particle size of 0.074 mm.

[0053] (2) Preparation of bioleaching medium: the solute is 2.0 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4·7H2O, 0.25 g / L anhydrous CaCl2 and 16 g / L reducing energy substrate, and the solvent is distilled water; wherein, the reducing energy substrate is 16 g / L sulfur; dispensed into 250 mL Erlenmeyer flasks at 100 mL / bottle; inoculated the above medium with 15% (v / v) seed culture of Thiobacillus thiooxidans to obtain bioleaching solution, and cultured in a shaker at 35℃ and 135 rpm, and monitored its pH and ORP changes;

[0054] After 10 days of shaking culture, when the pH of the bioleaching medium dropped to 0.8, 6g (solid-liquid ratio 6%) of the paint residue powder obtained in step (1) was added, and the culture was continued in a shaking incubator (30℃, 120rpm) for bioleaching. Samples were taken every 2 days, and the samples were centrifuged at 8000rpm for 10min to obtain the supernatant. The concentration of copper ions dissolved in the supernatant was measured. After 9 days of bioleaching, the concentration of copper ions dissolved no longer increased, and the leaching was completed. The leachate was collected by centrifugation or filtration. The copper ion dissolution rate was 80.29%.

[0055] (3) Adjust the pH of the leachate obtained in step (2) to 2.0 with 1 mol / L sodium carbonate solution, mix it with the extractant composed of LIX984 and sulfonated kerosene DT100 (LIX984:DT100 = 10%) at a volume ratio of 1 / 3, shake for 10 min for extraction, let it stand to separate the layers, the upper phase is the copper-enriched oil phase and the lower phase is the aqueous phase, separate the copper-enriched oil phase and the aqueous phase; take the lower aqueous phase to determine the copper concentration, and calculate the extraction rate as 99.46%;

[0056] (4) The oil phase obtained in step (3) was mixed with 200 g / L sulfuric acid solution at a volume ratio of 1 / 1, shaken for 10 min for back extraction, allowed to stand and separate into layers, and the lower aqueous phase was taken to determine the copper concentration. The back extraction rate was calculated to be 95.33%.

[0057] The organic phase obtained by back-extraction regains its extraction capacity and can be reused in step (3) to extract copper;

[0058] (5) Evaporate and cool the aqueous phase obtained in step (4) to obtain copper sulfate crystals.

[0059] Example 5

[0060] (1) Place copper-containing waste paint residue in an electric heating constant temperature drying oven and dry it at 80°C until constant weight. Then crush and grind it, and sieve it through a 200-mesh sieve for later use to obtain powder with a particle size of 0.074 mm.

[0061] (2) Preparation of bioleaching medium: The solutes are 2.0 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4·7H2O, 0.25 g / L anhydrous CaCl2 and 16 g / L reducing energy substrate, and the solvent is distilled water; wherein, the reducing energy substrate is a mixture of 16 g / L pyrite; dispensed into 250 mL Erlenmeyer flasks at 100 mL / bottle; inoculated the above medium with 15% (v / v) seed culture of Acidithiobacillus ferrooxidans to obtain bioleaching solution, and cultured in a shaker at 35℃ and 135 rpm, and monitored the changes in pH and ORP;

[0062] After 10 days of shaking culture, when the pH of the bioleaching medium dropped to 1.5, 6g (6% solid-liquid ratio) of the paint residue powder obtained in step (1) was added, and the culture was continued in a shaking incubator (45℃, 150rpm) for bioleaching. Samples were taken every 2 days, and the samples were centrifuged at 8000rpm for 10min to obtain the supernatant. The concentration of copper ions dissolved in the supernatant was measured. After 9 days of bioleaching, the concentration of copper ions dissolved no longer increased, and the leaching was completed. The leachate was collected by centrifugation or filtration. The copper ion dissolution rate was 87.74%.

[0063] (3) Adjust the pH of the leachate obtained in step (2) to 2.0 with 1 mol / L sodium carbonate solution, mix it with the extractant composed of LIX984 and sulfonated kerosene DT100 (LIX984:DT100 = 10%) at a volume ratio of 1 / 3, shake for 10 min for extraction, let it stand to separate the layers, the upper phase is the copper-enriched oil phase and the lower phase is the aqueous phase, separate the copper-enriched oil phase and the aqueous phase; take the lower aqueous phase to determine the copper concentration, and calculate the extraction rate as 99.46%;

[0064] (4) The oil phase obtained in step (3) was mixed with 200 g / L sulfuric acid solution at a volume ratio of 1 / 1, shaken for 10 min for back extraction, allowed to stand and separate into layers, and the lower aqueous phase was taken to determine the copper concentration. The back extraction rate was calculated to be 95.33%.

[0065] The organic phase obtained by back-extraction regains its extraction capacity and can be reused in step (3) to extract copper;

[0066] (5) Evaporate and cool the aqueous phase obtained in step (4) to obtain copper sulfate crystals.

Claims

1. A method for resource recovery of copper from spent paint sludge, characterized in that: The specific steps are as follows: (1) the waste paint residue containing copper is placed in an electric heating constant temperature drying oven at 80 DEG C to dry to constant weight, crushed and ground, screened through a 200 mesh sieve and used; (2) the bioleaching bacterial strain is inoculated into an inorganic salt culture medium, placed in a shaking bed and cultured, and the pH and ORP changes are monitored, the paint residue powder obtained in step (1) is added, and the bioleaching is continued to shake the bed to culture until the valuable metal ion copper in the leaching solution no longer increases, and the leaching solution is collected by centrifugation or suction filtration; the inorganic salt culture medium solute is 2.0 g / L of (NH4)2SO4, 1 g / L of KH2PO4, 0.5 g / L of MgSO4·7H2O, 0.25 g / L of anhydrous CaCl2 and 8-16 g / L of a reducing energy substrate, and the solvent is water; the reducing energy substrate is sulfur or pyrite or a mixture of sulfur and pyrite; the bioleaching bacterial strain is an autotrophic bacterium, including Thiobacillus thioxidans, Thiobacillus ferroxidans and Leptospirillum ferriphilum; when the energy substrate is sulfur, Thiobacillus thioxidans is inoculated; when the energy substrate is pyrite, Thiobacillus ferroxidans and Leptospirillum ferriphilum are inoculated respectively; when the energy substrate is sulfur and pyrite, a mixed bacterium of Thiobacillus thioxidans, Thiobacillus ferroxidans and Leptospirillum ferriphilum is inoculated; (3) the pH of the leaching solution obtained in step (2) is adjusted with 1 mol / L sodium carbonate solution, mixed with an extractant composed of LIX984 and sulfonated kerosene DT100, shaken for 10 min for extraction, and separated by layering; (4) the organic phase obtained in step (3) is back-extracted with a sulfuric acid solution, shaken for 10 min, and separated by layering; (5) the water phase obtained in step (4) is evaporated and cooled to crystallize copper sulfate crystals.

2. The method of claim 1, wherein: The inoculation concentration of the Thiobacillus thioxidans, Thiobacillus ferroxidans and Leptospirillum ferriphilum is 5-15% by volume / volume.

3. The method of claim 1, wherein: During the culture of the leaching bacterial strain, the pH and ORP changes are monitored every day, and when the pH drops to 0.6-1.4, the waste paint residue powder is added at 2-10% by weight / volume, i.e. the solid-liquid ratio is 2-10% g / mL.

4. The method of claim 1, wherein: The bioleaching shaking bed culture conditions are 25-45 DEG C and 100-180 rpm.

5. The method of claim 1, wherein: The pH of the leaching solution is adjusted to 1.0-4.0 with 1 mol / L sodium carbonate solution.

6. The method of claim 1, wherein: The extractant is composed of LIX984 and sulfonated kerosene DT100, and the volume / volume of LIX984:DT100 is 10-30%; the back-extractant is a 50-300 g / L sulfuric acid solution.

7. The method of claim 1, wherein: The volume ratio of the extracted organic phase to the water phase is 1:1-5:1, and the volume ratio of the back-extracted organic phase to the water phase is 3:1-1:

3.

8. The method of claim 1, wherein: The organic phase obtained by back-extraction has recovered extraction capacity and can be reused for copper extraction.

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