A method for recovering copper from citric acid leaching solution by organic solvent extraction

Abstract

The invention discloses a method for recovering copper in a citric acid leachate by an organic solvent extraction method. The copper-containing citric acid leachate is added to a constant temperature reactor and stirred evenly, and then LIX 84-I is added to the solution to adjust the pH value of the solution; after the extraction is completed, it is poured into a separatory funnel to separate the organic phase and the liquid phase; sulfuric acid solution is added to the organic phase obtained in the previous step for stripping, and after stirring, it is poured into a separatory funnel to separate the organic phase and the stripping solution; the stripping solution is evaporated and dried to recover the metal salt therein. The present invention uses the citric acid leachate of waste ternary lithium batteries as raw materials, and adopts an extraction method to selectively separate and recover the Cu element in the leachate, thereby realizing the efficient recycling of valuable metals. The recovery rate of Cu is as high as 99.5%, and the loss rates of nickel, cobalt, manganese, lithium and aluminum are all less than 5%. The method is low in cost, easy to separate, and has low energy consumption, and is an efficient method for recovering valuable metals.

Description

Technical Field

[0001] The invention belongs to the field of resource recycling and hydrometallurgy, and mainly relates to a method for recovering copper in citric acid leaching solution by an organic solvent extraction method. Background Art

[0002] With the rapid development of the electric vehicle industry and the rapid replacement of portable electronic products in recent years, while the demand and output of lithium-ion batteries continue to grow, the amount of discarded lithium-ion batteries has also increased dramatically. Discarded lithium-ion batteries contain a large amount of valuable metals such as lithium, cobalt, nickel, manganese, and copper, which have high recycling value. Irrational treatment will cause great waste of resources. In addition, the organic solvents, electrolytes, and heavy metals contained in lithium-ion batteries can easily cause serious environmental pollution and endanger human health.

[0003] The wet recovery process has attracted wide attention due to its high efficiency, low cost and pollution. Organic acids are gradually being adopted as leaching agents for waste lithium-ion batteries because of their mild acidity and no secondary pollution. Among many organic acids, citric acid has become a very reliable leaching agent because of its high acidity, low price and wide source. However, citric acid has strong complexing properties, which makes it difficult to recover valuable metals from the leachate. At present, most studies focus on the leaching process of citric acid, while there are few studies on the efficient recovery of various valuable metals from citric acid leachate. In addition, since the positive electrode materials in lithium-ion batteries have gradually diversified, such as nickel-cobalt-manganese ternary materials and lithium manganate materials, the leachate contains a large amount of metal ions with similar properties such as Co, Ni, Mn, and Cu, which poses a great challenge to the separation and extraction of various valuable metal ions in the leachate. The traditional wet process for recycling lithium cobalt oxide batteries has been difficult to adapt to the recycling of diversified waste lithium-ion batteries. Therefore, it is of great significance to study a green, efficient, simple and adaptable integrated recovery and treatment system for the leaching of waste lithium-ion batteries and the separation and purification of valuable metals.

[0004] Although many studies have reported the use of various organic solvents to extract and separate metals such as Co, Ni, Mn and Cu, there are still few studies on the extraction and separation of these metals from citric acid, which has strong complexing properties. Solvent extraction is widely used in the extraction and separation of metals in hydrometallurgy due to its high extraction rate and good selectivity. Summary of the invention

[0005] In view of the problem of recycling and resource utilization of metal Cu in the leachate of waste lithium batteries in the prior art, the present invention provides a simple and efficient method for recovering copper from the leachate.

[0006] To achieve the above object, the present invention adopts the following technical scheme: a method for recovering copper from citric acid leachate by organic solvent extraction, comprising the following steps:

[0007] Step 1: adding the copper-containing citric acid leachate into a constant temperature reactor and stirring evenly, then adding LIX84-I to the solution, and adjusting the pH value of the solution; in the present invention, the citric acid leachate of waste ternary lithium batteries is used as the raw material, LIX 84-I is used as the organic extractant, and kerosene is used as the diluent.

[0008] Step 2: After the mixed solution in step 1 is extracted, pour it into a separatory funnel to separate the organic phase and the liquid phase;

[0009] Step 3: Add sulfuric acid solution to the organic phase obtained in step 2 for stripping, and pour into a separatory funnel after stirring to separate the organic phase and the stripping solution;

[0010] Step 4: evaporate and dry the stripping solution obtained in step 3 to recover the metal salt therein.

[0011] Preferably, the copper-containing citric acid leachate in step 1 is citric acid leachate of waste ternary lithium batteries.

[0012] Preferably, 5M NaOH or 2M H2SO4 is used to adjust the pH of the solution in step 1. The pH value of the reaction solution has a great influence on the extraction rate of Cu, so it is necessary to adjust the pH value of the solution to a set value.

[0013] Preferably, the extraction conditions in step 1 are that the solution pH range is between 0.5 and 3.0, the LIX 84-I concentration is 2-14 vol%, and the O / A ratio is 0.25-4. The organic extractant LIX 84-I is a water-insoluble 2-hydroxy-5-nonylacetophenone oxime, which can effectively extract and separate Cu from other transition metals. In order to improve the extraction rate of Cu and reduce the loss rate of other metals such as Co, Ni, Mn, and Li, the above reaction conditions need to be optimized to a certain range.

[0014] Preferably, the extraction time in step 2 is 1-5 min. The extraction time is an important factor affecting the extraction rate of Cu and the loss rate of other valuable metals.

[0015] Preferably, the concentration of the sulfuric acid solution in step 3 is 0.5-3 mol / L, and O / A=1. The reaction that occurs when stripping Cu from the loaded LIX 84-I is: CuA 2(org) +H2SO 4(aq) →CuSO 4(aq) +2HA (org) .

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] (1) The method of the present invention solves the problem of difficulty in selectively separating multiple metal elements in a citric acid system with strong complexing properties, improves the practicality of citric acid in wet recovery and treatment of waste lithium batteries, and is also applicable to other non-complexing acid leaching solutions.

[0018] (2) The selected extractant has high selectivity. The selected LIX 84-I extractant only precipitates and separates Cu metal under specific conditions, and the loss rate of other metals is relatively small. The extraction rate of Cu is as high as over 95%, and the loss rates of nickel, cobalt, manganese, lithium, and aluminum are all less than 5%.

[0019] (3) In the production of the present invention, the organic extractant LIX 84-I can be reused, thereby reducing production costs and energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0022] The present invention uses citric acid leachate of waste ternary lithium batteries as raw material, and proposes a simple and economical method for separating and recovering copper from citric acid leachate. LIX 84-I (2-hydroxy-5-nonylacetophenone oxime) is used to efficiently separate and recover the Cu element in the leachate, while ensuring a high recovery rate and high purity of metal Cu in the leachate, it also reduces the loss rate of other valuable metals (lithium, nickel, cobalt, manganese, aluminum) in the leachate, improves the added value of the recovered product and the environmental friendliness of the treatment process, and realizes the green and efficient recovery of metals in the citric acid leachate.

[0023] The method for recovering copper from citric acid leachate by organic solvent extraction of the present invention uses citric acid leachate of waste ternary lithium battery as raw material, LIX 84-I as organic extractant, kerosene as diluent, and the process steps are as follows:

[0024] (1) Add a certain amount of citric acid leachate into a stirred reactor, and adjust the pH of the solution to a set value with 5 M NaOH or 2 M H2SO4;

[0025] (2) Add a certain amount of LIX 84-I to the above solution, and adjust the pH of the solution with 5M NaOH or 2M H2SO4. The pH range is 0.5-3.0, the concentration of LIX 84-I is 2-14 vol%, and the O / A ratio of the extract is 0.25-4.

[0026] (3) After the mixed solution has been extracted for a period of time, it is poured into a separatory funnel to separate the organic phase and the liquid phase. The extraction time is 1-5 min.

[0027] (4) Add a certain concentration of sulfuric acid solution to the organic extractant obtained in the third step for stripping, and the extraction phase O / A=1. After stirring for 5 minutes, pour it into a separatory funnel to separate the organic phase and the stripping solution. The sulfuric acid concentration is 0.5-3 mol / L.

[0028] (5) Evaporate and dry the stripping solution at 60°C to recover the metal salts therein.

[0029] The invention uses citric acid leachate of waste ternary lithium battery as raw material, LIX 84-I as organic extractant, kerosene as diluent to extract and recover Cu in the solution, and adjusts pH value, extractant concentration, O / A ratio and extraction time to ensure the extraction rate of Cu and reduce the loss of other valuable metals in the solution; in the stripping process, sulfuric acid solution is used to strip Cu in the stripping organic phase, and the stripping efficiency is ensured by controlling the sulfuric acid concentration.

[0030] Embodiment 1

[0031] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 50 mL of 10 vol% LIX 84-I (kerosene is a diluent) is added to the above solution, and the pH of the solution is adjusted to 2 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 1 min, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 3 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 5 min, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein.

[0032] It has been calculated that after the above process, the extraction rate of copper in the leaching solution reached 70.5%.

[0033] Embodiment 2

[0034] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 50 mL of 14 vol% LIX 84-I (kerosene as diluent) is added to the above solution, and the pH of the solution is adjusted to 2 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 2 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein. It is calculated that after the above process, the extraction rate of copper in the leachate reaches 98.5%.

[0035] Embodiment 3

[0036] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 50 mL of 2 vol% LIX 84-I (kerosene is a diluent) is added to the above solution, and the pH of the solution is adjusted to 2 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 2 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 4 minutes, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein.

[0037] It has been calculated that after the above process, the extraction rate of copper in the leaching solution reached 73.1%.

[0038] Embodiment 4

[0039] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 50 mL of 10 vol% LIX 84-I (kerosene as diluent) is added to the above solution, and the pH of the solution is adjusted to 0.5 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 5 min, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 0.5 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 5 min, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein.

[0040] It has been calculated that after the above process, the copper extraction rate in the leaching solution reached 5.3%.

[0041] Embodiment 5

[0042] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 50 mL of 10 vol% LIX 84-I (kerosene is a diluent) is added to the above solution, and the pH of the solution is adjusted to 3 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 3 minutes, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 2.5 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein.

[0043] It has been calculated that after the above process, the extraction rate of copper in the leaching solution reached 95.1%.

[0044] Embodiment 6

[0045] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 12.5 mL of 10 vol% LIX 84-I (kerosene is a diluent) is added to the above solution, and the pH of the solution is adjusted to 2 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 2 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein.

[0046] It has been calculated that after the above process, the extraction rate of copper in the leaching solution reached 50.2%.

[0047] Embodiment 7

[0048] The method of recovering copper from citric acid leachate by organic solvent extraction is as follows: 50 ml of citric acid leachate of waste ternary lithium battery (Cu content is 2.1 g / L) is added to a 200 mL constant temperature reactor, 200 mL of 10 vol% LIX 84-I (kerosene as diluent) is added to the above solution, and the pH of the solution is adjusted to 2 with 5M NaOH or 2M H2SO4. After the mixed solution is extracted for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the liquid phase. Subsequently, 3 mol / L sulfuric acid solution is added to the separated organic extractant at a ratio of O / A=1 for stripping, and after stirring for 5 minutes, it is poured into a separatory funnel to separate the organic phase and the stripping solution, and finally the stripping solution is evaporated and dried at 60°C to recover the metal salt therein.

[0049] It has been calculated that after the above process, the extraction rate of copper in the leaching solution reached 98.1%.

Claims

1. A method for recovering copper from citric acid leachate by organic solvent extraction, characterized in that: The steps include: Step 1: adding the copper-containing citric acid leaching solution into a constant temperature reactor and stirring evenly, then adding LIX 84-I to the solution, and adjusting the pH value of the solution; wherein the copper-containing citric acid leaching solution is the citric acid leaching solution of waste ternary lithium batteries, LIX 84-I is used as an organic extractant, and kerosene is used as a diluent; Step 2: After the mixed solution in step 1 is extracted, pour it into a separatory funnel to separate the organic phase and the liquid phase; Step 3: Add sulfuric acid solution to the organic phase obtained in step 2 for stripping, and pour into a separatory funnel after stirring to separate the organic phase and the stripping solution; Step 4: evaporate and dry the stripping solution obtained in step 3 to recover the metal salt therein.

2. The method for recovering copper from citric acid leachate by organic solvent extraction according to claim 1, characterized in that: In step 1, 5M NaOH or 2M H2SO4 is used to adjust the pH of the solution.

3. The method for recovering copper in citric acid leachate by organic solvent extraction according to claim 2, characterized in that: The extraction conditions in step 1 are as follows: the solution pH range is between 0.5-3.0, the LIX 84-I concentration is 2-14 vol%, and the O / A ratio is 0.25-4.

4. The method for recovering copper from citric acid leachate by organic solvent extraction according to claim 3, characterized in that: The extraction time in step 2 is 1-5 min.

5. The method for recovering copper from citric acid leachate by organic solvent extraction according to claim 4, characterized in that: The concentration of the sulfuric acid solution in step 3 is 0.5-3 mol / L, O / A=1.

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