Leaching recovery method of ternary lithium battery waste

Abstract

The invention discloses a leaching recovery method of ternary lithium battery waste. The method comprises the following steps: discharging and disassembling a waste lithium battery, sorting and grinding to obtain a powder positive electrode mixture, and roasting the obtained powder positive electrode mixture to obtain a roasted ternary lithium battery waste material; sulfuric acid is added into the roasted ternary lithium battery waste for mixing, and then a reducing agent is introduced for a reduction leaching reaction; and after the reaction is finished, stopping introducing the reducing agent, continuously heating to 105-115 DEG C, reacting for 1-3 hours, and filtering after the reaction to obtain a reduction leaching solution and waste graphite slag. According to the technical scheme, the raw material for preparing the battery grade graphite can be obtained, meanwhile, nickel, cobalt, manganese and lithium in the waste ternary lithium battery are efficiently separated and recycled, and the method has the advantages of being simple in process, environmentally friendly, high in safety, high in economic benefit, high in production efficiency, high in recycling rate and the like and has wide application prospects.

Description

1. Technical Field:

[0001] The present invention belongs to the technical field of ternary battery recycling in the new energy battery material industry, and specifically relates to a leaching and recycling method for ternary lithium battery waste. 2. Background technology:

[0002] Lithium-ion batteries have many advantages, including high energy density, excellent cycle performance, high charging efficiency, low self-discharge, and no memory effect. They are widely used in power batteries and other energy storage materials, and are used to produce new energy electric vehicles and daily consumer electronic products. Ternary polymer lithium batteries refer to lithium batteries whose positive electrode materials use lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminum oxide as ternary positive electrode materials. Ternary composite positive electrode materials are made from nickel salts, cobalt salts, and manganese salts. The ratio of nickel, cobalt, and manganese can be adjusted according to actual needs. The ternary composite positive electrode material is combined with negative electrode materials, electrolytes, separators, and other materials to prepare ternary lithium batteries. Batteries using ternary materials as positive electrodes are safer than lithium cobalt oxide batteries.

[0003] Waste lithium-ion batteries typically contain large amounts of hazardous organic pollutants and nonferrous metal inorganic compounds. Improper waste disposal poses a serious threat to human health, the environment, and biota. The nonferrous metals and negative electrode graphite in waste batteries have recycling value and can be reused in the manufacture of new energy materials, reducing environmental pollution and generating positive economic benefits. Waste ternary lithium-ion batteries contain large amounts of valuable metals such as nickel, cobalt, manganese, and lithium. Effective recycling of these metals is beneficial to environmental protection and improves economic efficiency.

[0004] In summary, with the growing installed capacity of new energy ternary lithium batteries, it is imperative to research and develop a method for effectively treating ternary lithium battery waste. The following are existing treatment technologies for ternary lithium electrode waste and the problems they present.

[0005] 1) Mechanical method: After pre-processing, the battery fragments are passed through a magnetic separator to remove magnetic material. The finely crushed material is then fed into an airflow de-powdering machine for flexible de-powdering, separating the battery powder from the electrode. The battery black powder is collected in a material powder bin. This method avoids the problem of powder entrainment caused by curling of the battery electrode and allows for flexible adjustment of the airflow de-powdering speed, improving de-powdering efficiency.

[0006] 2) Heat treatment method:

[0007] a. Conventional heat treatment: Taking advantage of the different pyrolysis temperatures of the positive electrode active material, binder, conductive agent, and aluminum foil, the appropriate temperature is selected to separate the positive electrode active material from the aluminum foil and remove organic impurities. For example, PVDF decomposes at 350-600°C to obtain a higher-purity positive electrode material.

[0008] b. Low-temperature heat treatment: By introducing substances such as calcium oxide, the decomposition temperature of PVDF is reduced, and the positive electrode active material and aluminum foil are separated at a low temperature of 300°C, reducing the environmental hazards caused by high-temperature treatment.

[0009] 3) Chemical method:

[0010] a. Pyrometallurgical Recovery Processes: ① Slag Reduction Smelting: Utilizes a basic slag system to enrich and precipitate valuable metals from spent batteries, while organic components act as reducing agents to promote the formation of metal alloy compounds. However, lithium recovery rates are low, requiring further slag treatment. ② Carbothermal Reduction: Utilizes a carbon source as a reducing agent to convert cathode materials into metals and transition metal oxides at a specific temperature, thereby increasing lithium recovery rates. ③ Salt-Assisted Roasting: Utilizes a chlorinating agent to react with metals and metal oxides to produce metal chlorides, which are then separated and recovered based on their water solubility.

[0011] b. Wet recovery process: Using acid, alkali, salt or organic acid as a leaching agent, the valuable metals in the cathode material are leached into a solution, and then separated and purified through solvent extraction, chemical precipitation and other methods. Among them, organic acid leaching is more environmentally friendly, but the cost is higher. 3. Summary of the invention:

[0012] The technical problem to be solved by the present invention is: in response to the existing state of the art and existing problems in treating ternary lithium battery waste, the present invention provides a leaching and recovery method for ternary lithium battery waste. The technical solution of the present invention can produce raw materials for preparing battery-grade graphite, while also efficiently separating and recovering nickel, cobalt, manganese, and lithium from used ternary lithium batteries. This method has the advantages of a simple process, environmental friendliness, high safety, high economic benefits, high production efficiency, and high recovery rate, and has broad application prospects.

[0013] In order to solve the above problems, the technical solution adopted by the present invention is:

[0014] The present invention provides a leaching and recovery method for ternary lithium battery waste, which comprises the following steps:

[0015] 1) discharging and disassembling the waste lithium batteries, sorting and grinding to obtain a powdered positive electrode mixture, and roasting the obtained powdered positive electrode mixture to obtain roasted ternary lithium battery waste;

[0016] 2) adding sulfuric acid to the calcined ternary lithium battery waste to mix, and then introducing a reducing agent to perform a reduction leaching reaction;

[0017] 3) After the reaction in step 2) is completed, the introduction of the reducing agent is stopped, and the temperature is continued to be raised to 105-115° C. for reaction for 1-3 hours. After the reaction, the reaction is filtered to obtain a reduced leaching solution and waste graphite slag.

[0018] According to the above-mentioned leaching and recovery method of ternary lithium battery waste, the equipment used for roasting in step 1) is a muffle furnace, the roasting temperature is 300-500° C., and the roasting time is 1-3 hours.

[0019] According to the above-mentioned leaching and recovery method of ternary lithium battery waste, in the reduction leaching reaction process of step 2), the initial acid concentration is 80-200 g / L, the liquid-solid ratio is 3-6:1, the reaction temperature is 50-90°C, the reaction time is 2-4h, and the pressure is 0.1-0.4Mpa.

[0020] According to the above-mentioned leaching and recovery method of ternary lithium battery waste, the reducing agent in step 2) is the flue gas generated during the zinc smelting and roasting process after dust collection and purification.

[0021] According to the above-mentioned leaching and recovery method of ternary lithium battery waste, the introduction amount of the reducing agent is 15 to 20 L / min.

[0022] According to the above-mentioned leaching and recovery method of ternary lithium battery waste, the main components and their contents in the reduction leachate obtained in step 3) are Co 10-15g / L, Ni 16-21g / L, and Mn 26-31g / L; the obtained reduction leachate is used for subsequent extraction and purification to recover Co, Ni, and Mn; and the obtained waste graphite slag is used as a raw material for preparing battery-grade graphite.

[0023] According to the above-mentioned leaching and recovery method for ternary lithium battery waste, the leaching rates of nickel, cobalt and manganese in the battery waste are all ≥98%, and the lithium leaching rate is 85-92%.

[0024] The positive beneficial effects of the present invention are:

[0025] 1. The technical solution of the present invention uses waste ternary lithium batteries as raw materials, roasts them in a muffle furnace, mixes the battery waste powder with sulfuric acid, controls the initial acidity and liquid-to-solid ratio, heats, and adds a reducing agent (i.e., flue gas generated during zinc smelting and roasting after dust collection and purification, which is a mixture of sulfur dioxide, nitrogen and oxygen) for reduction leaching. After the reaction, the flue gas is filtered to obtain a reduction leachate and raw materials for preparing battery-grade graphite products (i.e., waste graphite slag). The leaching rates of nickel, cobalt and manganese in the battery waste reach more than 98%, and the lithium leaching rate reaches 85-92%.

[0026] 2. The process of the present invention is short, the leaching rate is high, and the cost is low, thereby achieving efficient recovery and utilization of valuable metals such as nickel, cobalt, manganese and lithium.

[0027] 3. The treatment process of the present invention has only one step and a short process. The leaching rates of nickel, cobalt and manganese are all above 98%. The leaching rate is high. The flue gas from the zinc smelting and roasting process is used as a reducing agent instead of hydrogen peroxide for leaching, which is low in cost and high in economic benefit. The remaining waste gas can be returned to the original acid production process, which is environmentally friendly. The obtained leachate can be purified by mature processes and can be used to prepare a variety of products. It has high flexibility and has greatly improved the shortcomings of the existing technology and has industrial application prospects.

[0028] To sum up, the technical solution of the present invention is to use sulfur dioxide oxygen-containing flue gas instead of traditional hydrogen peroxide for leaching, and efficiently separate and recover nickel, cobalt, manganese and lithium in waste ternary lithium batteries. It has the advantages of simple process, environmental friendliness, high safety, high economic benefits, high production efficiency and high recovery rate. It has great improvements on the shortcomings of the existing technology and has industrial application prospects. 4. Description of the accompanying drawings:

[0029] Figure 1 Schematic diagram of the process flow of the ternary lithium battery waste leaching and recovery method of the present invention. V. Specific implementation methods:

[0030] The present invention is further described below with reference to the following examples, but the scope of protection of the technical solution of the present invention is not limited thereto.

[0031] In the following examples, battery black powder is used as raw material. The battery black powder contains 10.47% nickel, 6.77% cobalt, 16.67% manganese and 4% lithium.

[0032] Example 1:

[0033] The leaching and recovery method of ternary lithium battery waste of the present invention has the following detailed steps:

[0034] 1) discharging and disassembling the waste lithium battery, sorting and grinding to obtain a powdered positive electrode mixture, and calcining the obtained powdered positive electrode mixture in a muffle furnace at a calcination temperature of 450° C. and a calcination time of 2 h to obtain calcined battery black powder (i.e., calcined ternary lithium battery waste);

[0035] 2) adding sulfuric acid to the calcined battery black powder and mixing, and then introducing a reducing agent to carry out a reduction leaching reaction;

[0036] During the reduction leaching reaction, after adding sulfuric acid, the initial acid concentration was controlled to be 160 g / L, the liquid-solid ratio was 6:1, the reaction temperature was 70°C, the reaction time was 3 h, and the pressure was 0.25 MPa.

[0037] The reducing agent introduced is the flue gas generated during the zinc smelting and roasting process after dust collection and purification (the flue gas after dust collection is a mixture of sulfur dioxide, oxygen and nitrogen, of which sulfur dioxide is 8%, oxygen is 9%, and the rest is nitrogen); the reducing agent introduction rate is 16L / min;

[0038] 3) After the reaction in step 2) is completed, the introduction of the reducing agent is stopped, and the temperature is continued to be raised to 105-115° C. for reaction for 1 hour. After the reaction, the reaction is filtered to obtain a black powder reduction leaching solution and waste graphite slag.

[0039] The main components and their contents in the obtained black powder reduction leaching solution are Co 11.08 g / L, Ni 17.37 g / L, and Mn 27.53 g / L; the obtained reduction leaching solution is used for subsequent extraction and purification to recover Co, Ni, and Mn; and the obtained waste graphite slag is used as a raw material for preparing battery-grade graphite.

[0040] In this embodiment, the nickel leaching rate is 99.56%, the cobalt leaching rate is 98.2%, the manganese leaching rate is 99.1%, and the lithium leaching rate is 89.8%.

[0041] Example 2:

[0042] The leaching and recovery method of ternary lithium battery waste of the present invention has the following detailed steps:

[0043] 1) discharging and disassembling the waste lithium battery, sorting and grinding to obtain a powdered positive electrode mixture, and calcining the obtained powdered positive electrode mixture in a muffle furnace at a calcination temperature of 400° C. and a calcination time of 2 h to obtain ternary lithium battery waste;

[0044] 2) adding sulfuric acid to the calcined ternary lithium battery waste to mix, and then introducing a reducing agent to perform a reduction leaching reaction;

[0045] During the reduction leaching reaction, after adding sulfuric acid, the initial acid concentration was controlled to be 180 g / L, the liquid-solid ratio was 5:1, the reaction temperature was 70°C, the reaction time was 3 h, and the pressure was 0.25 MPa.

[0046] The reducing agent introduced is the flue gas generated during the zinc smelting and roasting process after dust collection and purification (the flue gas after dust collection is a mixture of sulfur dioxide, oxygen and nitrogen, of which sulfur dioxide is 8%, oxygen is 9%, and the rest is nitrogen); the reducing agent introduction rate is 16L / min;

[0047] 3) After the reaction in step 2) is completed, the introduction of the reducing agent is stopped, and the temperature is continued to be raised to 105-115° C. and reacted for 1.5 hours. After the reaction, the reaction is filtered to obtain a black powder reduction leaching solution and waste graphite slag.

[0048] The main components and their contents in the obtained black powder reduction leaching solution are Co 13.38 g / L, Ni 20.79 g / L, and Mn 30.11 g / L; the obtained reduction leaching solution is used for subsequent extraction and purification to recover Co, Ni, and Mn; and the obtained waste graphite slag is used as a raw material for preparing battery-grade graphite.

[0049] In this embodiment, the nickel leaching rate is 99.3%, the cobalt leaching rate is 98.8%, the manganese leaching rate is 99.3%, and the lithium leaching rate is 88.2%.

Claims

1. A leaching and recovery method for ternary lithium battery waste, characterized in that: The leaching recovery method comprises the following steps: 1) discharging and disassembling the waste lithium batteries, sorting and grinding to obtain a powdered positive electrode mixture, and roasting the obtained powdered positive electrode mixture to obtain roasted ternary lithium battery waste; 2) adding sulfuric acid to the calcined ternary lithium battery waste to mix, and then introducing a reducing agent to perform a reduction leaching reaction; 3) After the reaction in step 2) is completed, the introduction of the reducing agent is stopped, and the temperature is continued to be raised to 105-115° C. for reaction for 1-3 hours. After the reaction, the reaction is filtered to obtain a reduced leaching solution and waste graphite slag.

2. The leaching and recovery method for ternary lithium battery waste according to claim 1, characterized in that: The equipment used for the calcination in step 1) is a muffle furnace, the calcination temperature is 300-500° C., and the calcination time is 1-3 hours.

3. The leaching and recovery method for ternary lithium battery waste according to claim 1, characterized in that: Step 2) During the reduction leaching reaction, the initial acid concentration is 80-200 g / L, the liquid-solid ratio is 3-6:1, the reaction temperature is 50-90° C., the reaction time is 2-4 h, and the pressure is 0.1-0.4 MPa.

4. The leaching and recovery method for ternary lithium battery waste according to claim 1, characterized in that: The reducing agent in step 2) is the flue gas generated during the zinc smelting and roasting process after dust collection and purification.

5. The leaching and recovery method for ternary lithium battery waste according to claim 4, characterized in that: The amount of the reducing agent introduced is 15 to 20 L / min.

6. The leaching and recovery method for ternary lithium battery waste according to claim 1, characterized in that: The main components and contents of the reduction leaching solution obtained in step 3) are Co 10-15 g / L, Ni 16-21 g / L, and Mn 26-31 g / L; the obtained reduction leaching solution is used for subsequent extraction and purification to recover Co, Ni, and Mn; and the obtained waste graphite slag is used as a raw material for preparing battery-grade graphite.

7. The leaching and recovery method for ternary lithium battery waste according to claim 1, characterized in that: The leaching rates of nickel, cobalt and manganese in the battery waste are all greater than or equal to 98%, and the leaching rate of lithium is 85-92%.

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