Method for intensively leaching valuable metal from waste lithium ion battery positive electrode material

Abstract

The invention belongs to the technical field of waste lithium battery recovery, and particularly relates to a method for intensively leaching valuable metals from a waste lithium ion battery positive electrode material, which comprises the following steps: placing waste lithium battery positive electrode powder, a leaching agent and a reducing agent in an electrolytic bath, and carrying out intensified leaching with the assistance of a chaotic circuit to obtain a leaching solution; wherein the chaotic circuit provides chaotic current for the waste lithium battery positive electrode powder, the leaching agent and the reducing agent in the electrolytic bath. According to the invention, by utilizing the nonlinear and aperiodic change characteristics of the chaotic circuit, electrochemical oscillation and electrode polarization in the leaching process are effectively inhibited, meanwhile, the oxidation-reduction potential of various valuable metal ions is changed, the ion migration rate and diffusivity are improved, the solid-liquid interface reaction rate is increased, and the leaching efficiency is improved. And therefore, the leaching efficiency of the valuable metal is improved, reagent consumption is reduced, environmental pollution is reduced, and efficient, green and low-cost leaching of the valuable metal is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste lithium battery recycling, and particularly relates to a method for intensifying the leaching of valuable metals from the cathode material of waste lithium-ion batteries. Background Art

[0002] With the large-scale retirement of power batteries, the scale of the power battery recycling market is increasing year by year. The huge retirement volume poses severe challenges to resource recycling and environmental protection. A series of policies in China, such as the "New Energy Vehicle Industry Development Plan (2021 - 2035)" and the "Circular Economy Development Plan for the 14th Five-Year Plan", clearly state that a complete power battery recycling system should be constructed to improve resource utilization efficiency, reduce environmental pollution, and promote the green and sustainable development of the new energy industry.

[0003] The cathode material of waste lithium-ion batteries contains various valuable metals. Direct discarding will cause serious environmental pollution and resource waste. At present, wet processes are basically adopted in China to recycle waste lithium batteries, and generally a composite leaching system of inorganic acid and hydrogen peroxide is used. However, there is still room for optimization in the leaching efficiency of valuable metals in the cathode material of waste lithium batteries by this method. For example, during the leaching process, it is restricted by reaction kinetics and interfacial reactions, resulting in problems such as high energy consumption, high acid consumption, and low leaching efficiency. In the wet process, leaching is one of the crucial steps because the leaching effect directly affects the overall recovery rate of each metal in the wet recycling process. Leaching can be divided into methods such as inorganic acid leaching, organic acid leaching, alkali leaching, special solvent leaching, biological leaching, and externally field-assisted intensifying leaching such as electric field, magnetic field, microwave field, ultrasonic wave, as well as mechanochemical-assisted intensifying leaching according to different leaching agents and leaching methods. Each of the above methods has certain defects, such as the need for a large amount of acid, alkali reagents, reducing agents, and low leaching efficiency. Therefore, integrating and improving or developing new leaching technologies to achieve green, high-efficiency, and low-cost leaching of the cathode material of waste lithium-ion batteries is an urgent problem to be solved. Summary of the Invention

[0004] The present invention aims to provide a method for intensifying the leaching of valuable metals from the cathode material of waste lithium-ion batteries to solve the problems of low leaching efficiency, high reagent consumption, and high cost in the existing technology for the cathode material of waste lithium batteries.

[0005] To achieve the above object, the solution of the present invention is: A method for intensifying the leaching of valuable metals from the cathode material of waste lithium-ion batteries, including a leaching step: placing the cathode powder of waste lithium batteries, a leaching agent, and a reducing agent in an electrolytic cell, and performing intensifying leaching with the assistance of a chaotic circuit to obtain a leaching solution; wherein, the chaotic circuit provides a chaotic current for the cathode powder of waste lithium batteries, the leaching agent, and the reducing agent in the electrolytic cell.

[0006] The working principle and beneficial effects of this scheme are as follows: in this scheme, the nonlinear and non-periodic characteristics of the chaotic circuit are utilized to effectively suppress electrochemical oscillations and electrode polarization in the leaching process, thereby improving the current efficiency; at the same time, the chaotic circuit changes the redox potential of various valuable metal ions in the solution, increases the ion migration rate and diffusion capacity in the solution, enhances the reaction activity of the solid-liquid interface, reduces reagent consumption, shortens the leaching time, improves the leaching efficiency, reduces waste emissions, reduces environmental pollution, and realizes efficient, green and low-cost leaching of valuable metals.

[0007] Optionally, in the leaching step, the chaotic circuit comprises a DC power supply, a chaotic circuit board, a power amplifier, an oscilloscope, an anode and a cathode, and the bottom ends of the anode and the cathode are immersed below the liquid surface in the electrolytic cell.

[0008] Optionally, in the leaching step, the average chaotic current is 0.1-3A.

[0009] Optionally, in the leaching step, the average chaotic current is 0.5 to 1 A. Experiments have shown that when the average chaotic current is between 0.5 and 1 A, the leaching rate of each valuable metal can reach more than 98%.

[0010] Optionally, in the leaching step, the enhanced leaching reaction temperature is 25 to 90° C., the enhanced leaching reaction time is 30 to 180 min, and the enhanced leaching stirring speed is 300 to 800 rpm.

[0011] Optionally, in the leaching step, the enhanced leaching reaction time is 60 to 90 minutes, and the enhanced leaching stirring speed is 500 to 700 rpm.

[0012] Optionally, in the leaching step, the solid-liquid ratio between the waste lithium battery positive electrode powder and the leaching agent is 40 to 200 g / L, and the reducing agent additive is 1 to 40% of the mass of the waste lithium battery positive electrode powder.

[0013] Optionally, in the leaching step, the leaching agent is one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, tartaric acid, and malic acid, and the concentration of the leaching agent is 1 to 5 mol / L.

[0014] Optionally, in the leaching step, the reducing agent is one or more of hydrogen peroxide, sodium sulfite, thiourea, hydroxylamine hydrochloride, glucose, ascorbic acid, tartaric acid, ferrous sulfate, ammonium ferrous sulfate, ferrous chloride and active metal elements.

[0015] Optionally, a raw material processing step is further included before the leaching step: disassembling, crushing, cleaning and drying the raw material waste lithium batteries to obtain waste lithium battery positive electrode powder with a particle size of 30 to 150 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the chaotic circuit experimental circuit used in the embodiment of the present invention;

[0017] Figure 2 Schematic diagram of the DC electric field experimental circuit used in Comparative Example 1 of the present invention. Specific implementation manners

[0018] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0019] The present invention provides a method for enhancing the leaching of valuable metals from waste lithium-ion battery cathode materials, including the following steps:

[0020] S1. Raw material treatment step: Disassemble, crush, clean and dry the raw material waste lithium battery to obtain waste lithium battery cathode powder with a particle size of 30-150 μm. Among them, the particle size of the waste lithium battery cathode powder is preferably 50-100 μm, and the waste lithium battery includes one or more of lithium iron phosphate batteries, nickel cobalt manganese oxide batteries, nickel cobalt aluminum oxide batteries, cobalt oxide batteries, manganese oxide batteries and lithium titanate batteries.

[0021] S2. Leaching step: Place the waste lithium battery cathode powder obtained in step S1, the leaching agent and the reducing agent in an electrolytic cell, and perform enhanced leaching with the assistance of a chaotic circuit to obtain a leaching solution. In this step, a chaotic current is provided for the waste lithium battery cathode powder, the leaching agent and the reducing agent in the electrolytic cell through the chaotic circuit, and the average chaotic current is 0.1-3 A, preferably 0.5-1 A.

[0022] In addition, in the leaching step, the chaotic circuit consists of a DC power supply, a chaotic circuit board, a power amplifier, an oscilloscope, an anode and a cathode, and the bottoms of the anode and the cathode are immersed below the liquid level in the electrolytic cell; the enhanced leaching reaction temperature is 25-90 °C, the enhanced leaching reaction duration is 30-180 min, preferably 60-90 min, and the enhanced leaching stirring speed is 300-800 rpm, preferably 500-700 rpm.

[0023] In addition, in the leaching step, the leaching agent is one or more of an inorganic acid and an organic acid. Specifically, the inorganic acid includes but is not limited to hydrochloric acid, sulfuric acid and nitric acid, and the organic acid includes but is not limited to citric acid, tartaric acid and malic acid. The concentration of the leaching agent is 1 to 5 mol / L, preferably 1.5 to 3 mol / L, and the solid-liquid ratio between the leaching agent and the positive electrode powder of the waste battery is 40 to 200 g / L, preferably 60 to 120 g / L; the reducing agent is one or more of hydrogen peroxide, sodium sulfite, thiourea, hydroxylamine hydrochloride, glucose, ascorbic acid, tartaric acid, ferrous sulfate, ammonium ferrous sulfate, ferrous chloride and active metal elements, and the amount of the reducing agent added is 1 to 40% of the mass of the positive electrode powder of the waste lithium battery.

[0024] In the leaching solution obtained in the leaching step, the leaching rate of each valuable metal is 90 to 99.9 wt %.

[0025] The following specific examples are given to illustrate the present invention in detail. It should also be understood that the following examples are only used to specifically illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range according to the description herein, and are not limited to the specific values ​​​​exemplified below.

[0026] Example 1

[0027] This embodiment provides a method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials, comprising the following steps:

[0028] S1. Build a chaotic circuit: Connect the DC power supply, chaotic circuit board, power amplifier, oscilloscope, anode and cathode to obtain the following Figure 1 The experimental circuit shown in FIG. The anode and cathode are both graphite electrodes, and the distance between the anode and cathode is 25 mm. In addition, the chaotic circuit in this step is a prior art, and the chaotic circuit can be designed and manufactured with reference to "Introduction to Chaotic Circuits".

[0029] S2, raw material processing step: dismantling, crushing, washing and drying the raw material waste lithium battery to obtain waste lithium battery positive electrode powder with a particle size of 30 to 150 μm. Specifically, the waste lithium battery in this step is a waste nickel cobalt manganese oxide battery, and the waste nickel cobalt manganese oxide battery positive electrode powder is obtained, and the waste nickel cobalt manganese oxide battery positive electrode powder contains Li 5.98%, Ni 38.15%, Co 9.26%, Mn 8.20%, Cu 0.06%, Fe 0.51%, Al 2.33%, Ca 0.11%, Mg 0.14%, and C 2.08%.

[0030] S3. Leaching step: Measure 100 mL of H 2 SO 4 (2 mol / L) and pour it into a 250 mL electrolytic cell. Weigh 8 g of the spent cathode powder of the lithium nickel cobalt manganese oxide battery in step S2 and pour it into the above electrolytic cell, and then add 3 g of ferrous sulfate heptahydrate. Subsequently, place the electrolytic cell in a magnetic stirring water bath, maintain a constant temperature of 25°C, and react for 90 min under the stirring condition of 700 rpm to obtain a leaching solution. During this reaction, a chaotic current is provided for the liquid in the electrolytic cell through a chaotic circuit, and the average chaotic current is 0.943 A. It should be noted that the average chaotic current is the average value of the current data calculated from the current data at different time points during the entire experimental process collected by data acquisition software; specifically, in this step, during the enhanced leaching period (90 min), about 11,900 current data are collected according to the software automatic collection method (collect 2 - 3 times of current data every 1 s).

[0031] After the leaching is completed, turn off the DC power supply and the magnetic stirring water bath, take out the anode and cathode, filter by suction to obtain a filtrate, and after volume constant dilution of the filtrate, send it for ICP test analysis. After calculation, in this embodiment, the leaching rates of nickel, cobalt, manganese, and lithium reach 98.10 wt%, 98.32 wt%, 98.26 wt%, and 99.67 wt% respectively.

[0032] Example 2

[0033] The difference between this embodiment and Example 1 is only that: step S3 of this embodiment is different from step S3 of Example 1, and steps S1 and S2 of this embodiment are the same as steps S1 and S2 of Example 1.

[0034] Step S3 of this embodiment is as follows:

[0035] S3. Leaching step: Measure 100 mL of H 2 SO 4 (3 mol / L) and pour it into a 250 mL electrolytic cell. Weigh 12 g of the spent cathode powder of the lithium nickel cobalt manganese oxide battery in step S2 and pour it into the above electrolytic cell, and then add 0.6 g of ascorbic acid. Subsequently, place the electrolytic cell in a magnetic stirring water bath, maintain a constant temperature of 60°C, and react for 90 min under the stirring condition of 700 rpm to obtain a leaching solution. During this reaction, a chaotic current is provided for the liquid in the electrolytic cell through a chaotic circuit, and the average chaotic current is 0.502 A. It should be noted that the average chaotic current is the average value of the current data calculated from the current data at different time points during the entire experimental process collected by data acquisition software; specifically, in this step, during the enhanced leaching period (90 min), about 11,900 current data are collected according to the software automatic collection method (collect 2 - 3 times of current data every 1 s).

[0036] After the leaching is completed, turn off the DC power supply and the magnetic stirring water bath, take out the anode and cathode, perform suction filtration to obtain a filtrate, and after volume-fixing and diluting the filtrate, send it for ICP test and analysis. Through calculation, in this embodiment, the leaching rates of nickel, cobalt, manganese, and lithium reach 99.25 wt%, 98.89 wt%, 99.08 wt%, and 99.62 wt% respectively.

[0037] Example 3

[0038] The difference between this embodiment and Example 1 is only that: Step S3 of this embodiment is different from Step S3 of Example 1, and Step S1 and Step S2 of this embodiment are the same as Step S1 and Step S2 of Example 1.

[0039] Step S3 of this embodiment is as follows:

[0040] S3. Leaching step: Measure 100 mL of H 2 SO 4 (1 mol / L) and pour it into a 250 mL electrolytic cell. Weigh 6 g of the waste lithium nickel cobalt manganese oxide battery cathode powder in Step S2 and pour it into the above electrolytic cell, and then add 2.4 g of glucose. Subsequently, place the electrolytic cell in a magnetic stirring water bath, maintain a constant temperature of 90 °C, and react for 90 min under the stirring condition of 700 rpm to obtain a leaching solution. During this reaction, a chaotic current is provided for the liquid in the electrolytic cell through a chaotic circuit, and the average chaotic current is 0.751 A. It should be noted that the average chaotic current is the current average value calculated from the current data at different time points during the entire experimental process collected by data acquisition software; specifically, in this step, during the enhanced leaching period (90 min), about 11,900 current data are collected in total according to the software automatic collection method (collecting 2 - 3 current data per 1 s).

[0041] After the leaching is completed, turn off the DC power supply and the magnetic stirring water bath, take out the anode and cathode, perform suction filtration to obtain a filtrate, and after volume-fixing and diluting the filtrate, send it for ICP test and analysis. Through calculation, in this embodiment, the leaching rates of nickel, cobalt, manganese, and lithium reach 99.42 wt%, 99.61 wt%, 99.33 wt%, and 99.85 wt% respectively.

[0042] Comparative Example 1

[0043] This comparative example provides a method for enhancing the leaching of valuable metals from waste lithium-ion battery cathode materials, including the following steps:

[0044] S1. Build a DC circuit: Directly connect the DC power supply to the anode and cathode to obtain the experimental circuit as shown in Figure 2 wherein, both the anode and the cathode are graphite electrodes, and the distance between the anode and the cathode is 25 mm.

[0045] S2. Raw material treatment step: The raw material, waste lithium batteries, are disassembled, crushed, cleaned and dried to obtain waste lithium battery cathode powder with a particle size of 30 - 150 μm. Specifically, the waste lithium batteries in this step are waste nickel cobalt manganese acid lithium batteries, and waste nickel cobalt manganese acid lithium battery cathode powder is obtained. This waste nickel cobalt manganese acid lithium battery cathode powder contains 5.98% Li, 38.15% Ni, 9.26% Co, 8.20% Mn, 0.06% Cu, 0.51% Fe, 2.33% Al, 0.11% Ca, 0.14% Mg, and 2.08% C.

[0046] S3. Leaching step: Measure 100 mL of H 2 SO 4 (2 mol / L) and pour it into a 250 mL electrolytic cell. Weigh 8 g of the waste nickel cobalt manganese acid lithium battery cathode powder from step S2 and pour it into the above electrolytic cell, and then add 3 g of ferrous sulfate heptahydrate. Subsequently, place the electrolytic cell in a magnetic stirring water bath, maintain a constant temperature of 25°C, and react for 90 min under the stirring condition of 700 rpm to obtain a leaching solution. The direct current during this reaction is 0.95 A.

[0047] After the leaching is completed, turn off the direct current power supply and the magnetic stirring water bath, take out the anode and cathode, perform suction filtration to obtain a filtrate, and after volume - fixing dilution of the filtrate, send it for ICP test and analysis. Through calculation, in this example, the leaching rates of nickel, cobalt, manganese, and lithium reach 84.10 wt%, 78.32 wt%, 64.26 wt%, and 92.87 wt% respectively.

[0048] Comparative Example 2

[0049] This comparative example provides a method for enhancing the leaching of valuable metals from the cathode material of waste lithium - ion batteries. This method has no external electric field and includes the following steps:

[0050] S1. Raw material treatment step: The raw material, waste lithium batteries, are disassembled, crushed, cleaned and dried to obtain waste lithium battery cathode powder with a particle size of 30 - 150 μm. Specifically, the waste lithium batteries in this step are waste nickel cobalt manganese acid lithium batteries, and waste nickel cobalt manganese acid lithium battery cathode powder is obtained. This waste nickel cobalt manganese acid lithium battery cathode powder contains 5.98% Li, 38.15% Ni, 9.26% Co, 8.20% Mn, 0.06% Cu, 0.51% Fe, 2.33% Al, 0.11% Ca, 0.14% Mg, and 2.08% C.

[0051] S2. Leaching step: Measure 100 mL of H 2 SO 4(2 mol / L) was poured into a 250 mL conical flask. 8 g of the spent lithium nickel cobalt manganese oxide battery cathode powder in step S1 was weighed and poured into the above conical flask, and then 3 g of ferrous sulfate heptahydrate was added. Subsequently, the conical flask was placed in a magnetic stirring water bath, maintained at a constant temperature of 25 °C, and reacted for 90 min under the stirring condition of 700 rpm to obtain a leaching solution.

[0052] After the leaching was completed, the magnetic stirring water bath was turned off, and filtration was carried out to obtain a filtrate. After volume fixing and dilution of the filtrate, it was sent for ICP test analysis. Through calculation, in this example, the leaching rates of nickel, cobalt, manganese, and lithium reached 68.49 wt%, 51.99 wt%, 49.07 wt%, and 86.87 wt% respectively.

[0053] By comparing Example 1 with Comparative Example 1 and Comparative Example 2, it can be known that: the improvement rates of the leaching rate of nickel in Example 1 compared with Comparative Example 1 and Comparative Example 2 are 16.6% and 43.2% respectively, the improvement rates of the leaching rate of cobalt in Example 1 compared with Comparative Example 1 and Comparative Example 2 are 25.5% and 89.1% respectively, the improvement rates of the leaching rate of manganese in Example 1 compared with Comparative Example 1 and Comparative Example 2 are 52.9% and 100.2% respectively, and the improvement rates of the leaching rate of lithium in Example 1 compared with Comparative Example 1 and Comparative Example 2 are 7.3% and 14.7% respectively. This fully shows that the present invention adopts the chaotic circuit enhanced leaching technology, effectively improving the leaching rate of valuable metals in the spent lithium battery cathode powder.

[0054] The above are only the embodiments of the present invention. The invention is not limited to the fields involved in this embodiment. Common general knowledge such as the specific structures and characteristics known in the art are not described in detail here. Those of ordinary skill in the art know all the common general knowledge in the technical field to which the invention belongs before the application date or the priority date, can know all the existing technologies in this field, and have the ability to apply the conventional experimental means before this date. Those of ordinary skill in the art can, under the inspiration given in this application, combine their own abilities to improve and implement this solution. Some typical well-known structures or well-known methods should not become obstacles for those of ordinary skill in the art to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the present invention. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials, characterized in that: The method comprises the following steps: placing waste lithium battery positive electrode powder, a leaching agent and a reducing agent in an electrolytic cell, and performing enhanced leaching with the aid of a chaotic circuit to obtain a leachate; wherein the chaotic circuit provides a chaotic current for the waste lithium battery positive electrode powder, the leaching agent and the reducing agent in the electrolytic cell.

2. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: In the leaching step, the chaotic circuit comprises a DC power supply, a chaotic circuit board, a power amplifier, an oscilloscope, an anode and a cathode, and the bottom ends of the anode and the cathode are immersed below the liquid surface in the electrolytic cell.

3. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: In the leaching step, the average chaotic current is 0.1 to 3A.

4. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 3, characterized in that: During the leaching step, the average chaotic current is 0.5 to 1A.

5. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: In the leaching step, the enhanced leaching reaction temperature is 25-90° C., the enhanced leaching reaction time is 30-180 min, and the enhanced leaching stirring speed is 300-800 rpm.

6. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 5, characterized in that: In the leaching step, the enhanced leaching reaction time is 60 to 90 minutes, and the enhanced leaching stirring speed is 500 to 700 rpm.

7. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: In the leaching step, the solid-liquid ratio between the waste lithium battery positive electrode powder and the leaching agent is 40-200 g / L, and the reducing agent additive is 1-40% of the mass of the waste lithium battery positive electrode powder.

8. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: In the leaching step, the leaching agent is one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, tartaric acid, and malic acid, and the concentration of the leaching agent is 1 to 5 mol / L.

9. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: In the leaching step, the reducing agent is one or more of hydrogen peroxide, sodium sulfite, thiourea, hydroxylamine hydrochloride, glucose, ascorbic acid, tartaric acid, ferrous sulfate, ammonium ferrous sulfate, ferrous chloride and active metal elements.

10. The method for enhanced leaching of valuable metals from waste lithium-ion battery positive electrode materials according to claim 1, characterized in that: The method also includes a raw material processing step before the leaching step: disassembling, crushing, cleaning and drying the raw material waste lithium battery to obtain waste lithium battery positive electrode powder with a particle size of 30 to 150 μm.

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