Device and method for preparing ternary precursor by using waste lithium ion battery

Abstract

The invention discloses a device for preparing a ternary precursor by using a waste lithium ion battery. The device comprises at least one pre-melting kettle, a reaction kettle, a pre-filter, a fine filter, at least one flushing tank, a homogenizing kettle, a homogenizing kettle pre-filter, a homogenizing kettle fine filter, a crude product tank and a spray dryer. The device for preparing the ternary precursor by using the waste lithium ion battery has the advantages of simple structure, low energy consumption, high selectivity on transition metal elements and the like. The invention also provides a method for preparing the ternary precursor by using the waste lithium ion battery, the method has the advantages of greenness, environmental protection and selective lithium extraction through the step of deep eutectic solvent leaching, the recycling of the solvent and the separation of lithium and heavy metals are realized, and the subsequent efficient realization of lithium recovery is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of recycling waste lithium-ion batteries, and in particular to a device and a method for preparing a ternary precursor using waste lithium-ion batteries. Background Art

[0002] Lithium-ion batteries have the advantages of high operating voltage, high specific energy, large capacity, fast charge and discharge, good cycle performance, light weight and small size. They are the representative of modern high-performance batteries. Since their commercialization in the 1990s, they have gradually replaced other batteries and are widely used in mobile phones, laptops, portable electronic devices, electric bicycles and other fields. Lithium-ion batteries, such as ternary power batteries, lithium cobalt oxide batteries, and lithium manganese oxide batteries, are rich in valuable metals and have high recycling value. However, retired lithium-ion batteries, as a metal composite device, have the characteristics of high complexity and high pollution, which brings great difficulties to their clean and efficient recycling.

[0003] At present, the recycling methods of waste lithium-ion batteries mainly include pyrometallurgical recycling and wet recycling. The essence of pyrometallurgical recycling of lithium-ion batteries is to use chemical methods to reduce and roast lithium-ion batteries, then dissolve the remaining materials in strong acid after high-temperature heating, and finally extract them. This method has a recovery rate of up to 90%, but the energy consumption is high, and polluting gases are released during the treatment process, which affects the promotion of this process. The wet recycling of lithium-ion batteries is to recover metal elements after the positive electrode powder obtained by crushing, sorting and pre-treating the waste battery pack is reduced and acid-leached. The existing process has basically achieved efficient recovery of valuable metals such as nickel, cobalt, and manganese. This method has low energy consumption, but usually uses some corrosive solvents, which pose a serious threat to the environment and human health.

[0004] CN115347266A discloses a method and device for wet crushing and recycling of waste lithium-ion batteries, which crushes the waste lithium-ion batteries in a solution, performs hydrodynamic sorting, filtration, wet ball milling and screen sorting, and combines vacuum distillation and volatilization to obtain black powder. However, the above method has problems such as dust and electrolyte volatilization, as well as a lengthy recycling process, complex equipment, and a heavy burden on sewage treatment. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of low recovery rate, high energy consumption and environmental pollution in the prior art, and to provide a device and method for preparing a ternary precursor using waste lithium-ion batteries. The device and method of the invention have the advantages of high recovery rate, low energy consumption and environmental protection.

[0006] In order to achieve the above object, a device for preparing a ternary precursor using waste lithium-ion batteries is provided, the device comprising:

[0007] at least one pre-melting kettle for dissolving the solvent to form a liquid solvent;

[0008] A reaction kettle connected to the pre-melting kettle, used to leach the black powder of waste lithium-ion batteries with the liquid solvent from the pre-melting kettle to obtain a solid-liquid mixture;

[0009] A pre-filter, connected to the reactor, for preliminary filtering of the solid-liquid mixture;

[0010] A fine filter, connected to the pre-filter, for fine filtering the liquid phase after preliminary filtration by the pre-filter;

[0011] at least one washing tank connected to the pre-filter and the fine filter for washing the crude product after being filtered by the pre-filter and the fine filter;

[0012] A homogenizing kettle is used to purify the washed crude product by adding water to obtain a mixture;

[0013] A homogenizing kettle pre-filter, connected to the homogenizing kettle, for preliminarily filtering the mixture from the homogenizing kettle;

[0014] A homogenizing kettle fine filter is connected to the homogenizing kettle pre-filter and is used to finely filter the liquid phase filtered by the homogenizing kettle pre-filter to obtain a precursor solution;

[0015] A crude product tank, connected to the homogenizing kettle fine filter, for storing the precursor solution;

[0016] A spray dryer is connected to the product tank and is used to dry the precursor solution to obtain a ternary precursor.

[0017] A second aspect of the present invention provides a method for preparing a ternary precursor using waste lithium-ion batteries, the method comprising:

[0018] (1) first mixing the polyamino-containing substance with an acid solution to obtain a deep eutectic solvent; wherein the acid solution is selected from at least one of reducing organic carboxylic acids;

[0019] (2) performing a second mixing of the low eutectic solvent and the refined black powder of waste lithium ion batteries, and performing a first separation to obtain a crude product and a low eutectic solvent;

[0020] (3) washing the crude product with an alcohol; then mixing the washed crude product with deionized water for a third time; obtaining a precursor solution and a graphite mixture through a second separation; then drying the precursor solution to obtain a precursor;

[0021] (4) The precursor is mixed with a lithium salt and then calcined to obtain a positive electrode material.

[0022] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0023] (1) The device for preparing ternary precursors using waste lithium-ion batteries of the present invention has the advantages of simple structure, low energy consumption and high selectivity for transition metal elements.

[0024] (2) The method of the present invention has the advantages of being green, environmentally friendly and selectively extracting lithium through the step of leaching with a low eutectic solvent, and realizes the recycling of solvents and the separation of lithium and heavy metals, which is conducive to the subsequent efficient recovery of lithium. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a process for preparing a ternary precursor by recycling black powder of ternary waste lithium-ion batteries using a low eutectic solvent, provided by one embodiment of the present invention.

[0026] Description of Reference Numerals

[0027] 1-Diaphragm pump 2-Acid raw material tank 3-First pre-melting kettle

[0028] 4- Reactor 5- Pre-filter 6- Fine filter

[0029] 7-circulation tank 8-second pre-melting kettle 9-first flushing tank

[0030] 10- Second flushing tank 11- Homogenizing kettle 12- Heat exchanger

[0031] 13-Homogenizer pre-filter 14-Homogenizer fine filter 15-Crude product tank

[0032] 16-Spray dryer 17-Flushing tank 18-Steam distributor DETAILED DESCRIPTION

[0033] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0034] The first aspect of the present invention provides a device for preparing a ternary precursor using waste lithium-ion batteries, as shown in Figure 1, the device comprises:

[0035] at least one pre-melting kettle for dissolving a solid solvent to form a liquid solvent;

[0036] Reactor 4, connected to the pre-melting kettle, used to leach the refined black powder of the waste lithium-ion battery with the liquid solvent from the pre-melting kettle to obtain a solid-liquid mixture;

[0037] A pre-filter 5, connected to the reactor 4, for preliminary filtering of the solid-liquid mixture;

[0038] A fine filter 6, connected to the pre-filter 5, for fine filtering the liquid phase after preliminary filtration by the pre-filter 5;

[0039] at least one washing tank connected to the pre-filter 5 and the fine filter 6, for washing the crude product after being filtered by the pre-filter 5 and the fine filter 6;

[0040] A homogenizing kettle 11 is used to purify the washed crude product by adding water to obtain a mixture;

[0041] A homogenizing kettle pre-filter 13, connected to the homogenizing kettle 11, for preliminarily filtering the mixture from the homogenizing kettle;

[0042] The homogenizing kettle fine filter 14 is connected to the homogenizing kettle pre-filter 13 and is used to finely filter the liquid phase filtered by the homogenizing kettle pre-filter 13 to obtain a precursor solution;

[0043] A crude product tank 15, connected to the homogenizing kettle fine filter 14, for storing the precursor solution;

[0044] The spray dryer 16 is connected to the crude product tank 15 and is used to dry the precursor solution to obtain a ternary precursor.

[0045] According to the present invention, two-stage filtration is adopted, wherein the purpose of pre-filtration is to intercept a part of the larger particles of the material first to ensure the smoothness of the filtration; the purpose of fine filtration is to intercept the smaller particles of the material after flowing through the pre-filter to ensure complete filtration.

[0046] According to a preferred embodiment of the present invention, the pre-melting kettle comprises a first pre-melting kettle 3 and a second pre-melting kettle 8; the first pre-melting kettle 3 is used to provide liquid solvent to the reactor; the second pre-melting kettle 8 is a supplementary kettle, used to supplement liquid solvent to the reactor.

[0047] According to a preferred embodiment of the present invention, the flushing tank comprises a flushing storage tank 17, a first flushing tank 9 and a second flushing tank 10;

[0048] The flushing tank 17 is connected to the pre-filter 5 and the fine filter 6 in sequence, and is used to store the flushing agent and flush the materials in the pre-filter 5 and the fine filter 6;

[0049] The first flushing tank 9 is connected to the fine filter 6, and is used to receive the primary washing liquid after the pre-filter 5 and the fine filter 6 are flushed with the flushing agent in the flushing storage tank 17; the second flushing tank 10 is connected to the pre-filter 5, and is used to receive the secondary washing liquid after the pre-filter 5 and the fine filter 6 are flushed with the primary washing liquid in the first flushing tank 9.

[0050] According to the present invention, the above-mentioned flushing tank is provided to flush the organic matter remaining in the material.

[0051] According to a preferred embodiment of the present invention, the device further comprises:

[0052] an acid raw material tank 2, connected to the reaction kettle 4 and the pre-melting kettles 3 and 8, and used to provide acid liquid to the reaction kettle 4 and the pre-melting kettles 3 and 8;

[0053] A diaphragm pump 1 is connected to the acid raw material tank 2 and is used to add material to the acid raw material tank 2.

[0054] According to a preferred embodiment of the present invention, the device further comprises: a circulation tank 7 connected to the fine filter 6 and the reactor 4 , which is used to receive the liquid filtered by the fine filter 6 and return it to the reactor 4 .

[0055] According to a preferred embodiment of the present invention, the device further comprises:

[0056] The heat exchanger 12 is connected to the homogenizing kettle 11 and is used to reflux the water vapor volatilized from the homogenizing kettle 11;

[0057] The steam distributor 18 is connected to the jackets of the pre-melting kettles 3 , 8 , the reaction kettle 4 and the homogenizing kettle 11 , and is used to provide heat for the pre-melting kettles 3 , 8 , the reaction kettle 4 and the homogenizing kettle 11 .

[0058] In some embodiments of the present invention, the pre-melting kettles 3 and 8, the reaction kettle 4 and the homogenizing kettle 11 are provided with pressure gauges and thermometers for measuring the pressure and temperature inside the kettles.

[0059] In some embodiments of the present invention, a tank body with storage properties is provided with a liquid level meter for measuring the liquid level in the tank.

[0060] In some embodiments of the present invention, all liquids in the tank are transported (except for the acid raw material transported by the diaphragm pump) by gravity potential energy plus nitrogen pressure.

[0061] In the present invention, the reactor 4 is respectively connected to the acid raw material tank 2, the pre-melting tanks 3 and 8, the pre-filter 5, and the circulation tank 7, and is an important component for ensuring the circulation of the device. At the connection between it and each tank, a ball valve is provided to control the materials entering and leaving the reactor.

[0062] In some embodiments of the present invention, a thermometer and a pressure gauge are provided on the steam distributor to measure the steam temperature and pressure. Four stop valves are provided on the jacket pipelines connecting the steam distributor to the pre-melting kettle, the feeding kettle, the reactor, and the homogenizing kettle to control the jacket pressures of the jackets, respectively, thereby controlling the jacket temperatures of the jackets. Pressure gauges are provided on the jackets of the pre-melting kettle, the feeding kettle, the reactor, and the homogenizing kettle to measure the jacket temperatures of the jackets.

[0063] In the present invention, the filter residues in the four filters, namely the pre-filter 5, the fine filter 6, the homogenizing kettle pre-filter 13 and the homogenizing kettle fine filter 14, are taken out manually and added manually to the required kettle.

[0064] The device of the present invention adopts a low eutectic solvent to grade and intermittently cycle to treat ternary waste lithium-ion battery black powder, and has the advantages of good selectivity for transition metal elements, high leaching efficiency, simple operation, etc.

[0065] The second aspect of the present invention provides a method for preparing a ternary precursor using waste lithium-ion batteries, using the device described in the first aspect, the method comprising:

[0066] (1) first mixing the polyamino-containing substance with an acid solution to obtain a deep eutectic solvent; wherein the acid solution is selected from at least one of reducing organic carboxylic acids;

[0067] (2) performing a second mixing of the low eutectic solvent and the refined black powder of waste lithium ion batteries, and performing a first separation to obtain a crude product and a low eutectic solvent;

[0068] (3) washing the crude product with an alcohol; then mixing the washed crude product with deionized water for a third time; obtaining a precursor solution and a graphite mixture through a second separation; then drying the precursor solution to obtain a precursor;

[0069] (4) The precursor is mixed with a lithium salt and then calcined to obtain a positive electrode material.

[0070] According to the present invention, the step of leaching with a low eutectic solvent has the advantages of being green, environmentally friendly and selectively extracting lithium, realizes the recycling of solvents and the separation of lithium and heavy metals, and is conducive to the subsequent efficient recovery of lithium.

[0071] According to the present invention, the purpose of recycling waste lithium-ion batteries to regenerate positive electrode materials is achieved through the steps of leaching, alcohol washing, filtering and lithium supplementation roasting, and the steps are simple and easy to operate.

[0072] According to a preferred embodiment of the present invention, the polyamino-containing substance is selected from at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, benzidine, 4,4'-diamino-3,3'-dimethylbiphenyl, dianisidine, 2,6-diaminoanthracene and 4,4'-diaminoterphenyl.

[0073] According to a preferred embodiment of the present invention, the polyamino-containing substance is ethylenediamine and benzidine, and the molar ratio of the two is 1:2-8, for example, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, and any value in the range of any two values, but not limited to this.

[0074] According to a preferred embodiment of the present invention, in step (1), the molar ratio of the polyamino-containing substance to the acid solution is (1-5):(1-15), for example, 1:2, 1:3, 1:4, 1:5, 1:9, 1:10, 2:5, 2:7, 3:7, 4:15, 5:1, 5:2, 5:3, 5:8, 5:15, and any value in the range consisting of any two values, but not limited to these.

[0075] According to a preferred embodiment of the present invention, in step (1), the molar concentration of the reducing organic carboxylic acid in the polynary deep eutectic solvent is 0.2-15 mol / L, for example, 0.2 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 5 mol / L, 8 mol / L, 10 mol / L, 12 mol / L, 15 mol / L, and any value in the range of any two values, but not limited thereto.

[0076] According to a preferred embodiment of the present invention, the reducing organic carboxylic acid is at least one selected from aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids.

[0077] According to a preferred embodiment of the present invention, the aliphatic carboxylic acid is selected from at least one of formic acid, lactic acid, methanesulfonic acid, acetic acid, oxalic acid, propionic acid, malonic acid, n-butyric acid, maleic acid, tartaric acid, fumaric acid, adipic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, ricinoleic acid, citric acid and malic acid; preferably selected from at least one of formic acid, acetic acid, oxalic acid, propionic acid, malonic acid, n-butyric acid, tartaric acid, citric acid and malic acid.

[0078] According to a preferred embodiment of the present invention, the alicyclic carboxylic acid is selected from at least one of cyclopropylacetic acid, cyclobutaneacetic acid, cyclopentaneacetic acid, cyclohexaneacetic acid, cyclopentanecarboxylic acid and 1,3,5-cyclohexanetric acid; preferably selected from at least one of cyclopropylacetic acid, cyclobutaneacetic acid, cyclopentaneacetic acid, cyclohexaneacetic acid and cyclopentanecarboxylic acid.

[0079] According to a preferred embodiment of the present invention, the aromatic carboxylic acid is selected from at least one of benzoic acid, p-toluenesulfonic acid, phthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, 2,6-naphthalene dicarboxylic acid and cinnamic acid; preferably selected from at least one of p-toluenesulfonic acid and cinnamic acid.

[0080] According to a preferred embodiment of the present invention, the reducing organic carboxylic acid is selected from at least one of formic acid, lactic acid, methanesulfonic acid, acetic acid, oxalic acid, propionic acid, malonic acid, maleic acid, tartaric acid, fumaric acid, adipic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, ricinoleic acid, citric acid, malic acid, cyclopropylacetic acid, cyclobutaneacetic acid, cyclopentaneacetic acid, cyclohexaneacetic acid, 1,3,5-cyclohexanetricarboxylic acid, benzoic acid, p-toluenesulfonic acid, phthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, and 2,6-naphthalene dicarboxylic acid.

[0081] According to a preferred embodiment of the present invention, the reducing organic carboxylic acid is at least one selected from formic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, 2,6-naphthalene dicarboxylic acid and 1,3,5-cyclohexanetricarboxylic acid.

[0082] According to a preferred embodiment of the present invention, in step (2), the solid-liquid ratio of the refined black powder and the low eutectic solvent is 1g:(10-100)L, for example, 1g:10L, 1g:20L, 1g:50L, 1g:80L, 1g:100L, and any value in the range of any two values, but not limited thereto.

[0083] According to a preferred embodiment of the present invention, in step (3), the solid-liquid ratio of the washed crude product to deionized water is 1g:(10-100)L, for example, 1g:10L, 1g:20L, 1g:50L, 1g:80L, 1g:100L, and any value in the range of any two values, but not limited to this.

[0084] According to a preferred embodiment of the present invention, in step (4), the amount of lithium salt added is 1-1.5 times the amount of lithium element missing, calculated as lithium element.

[0085] According to a preferred embodiment of the present invention, in step (1), the temperature of the first mixing is 60-80° C., and the time is 20-60 min.

[0086] According to a preferred embodiment of the present invention, in step (2), the temperature of the second mixing is 100-150° C., and the time is 2-6 hours.

[0087] According to a preferred embodiment of the present invention, in step (3), the temperature of the third mixing is 60-90° C. and the time is 0.5-2 h.

[0088] According to a preferred embodiment of the present invention, in step (4), the calcination conditions include: first calcining at 500-800°C for 3-8h; and then calcining at 700-1000°C for 5-15h.

[0089] According to a preferred embodiment of the present invention, in step (2), the refined black powder of waste lithium-ion batteries is the screened material obtained by screening the lithium battery black powder using a 100-300 mesh screening machine.

[0090] According to the present invention, the material under the sieve is a refined black powder mixed with positive and negative electrode powders; the material on the sieve is a mixture of copper foil, aluminum foil, diaphragm and plastic.

[0091] According to a preferred embodiment of the present invention, the method for preparing the lithium battery black powder comprises: discharging the waste lithium ion battery, placing it in the air for disassembly, and then crushing the positive and negative electrode sheets.

[0092] The lithium battery black powder in the present invention can also be directly purchased from recycled lithium battery black powder.

[0093] According to the present invention, through the screening step, it has the advantages of high efficiency and simplicity, and achieves the effect of completely separating more than 95% of the copper and aluminum foils and plastic diaphragms in the black powder.

[0094] According to a particularly preferred embodiment of the present invention, a device for preparing a ternary precursor using waste lithium-ion batteries, such as Figure 1As shown, it includes: an acid raw material tank 2; a first pre-melting kettle 3, which is connected to the acid raw material tank 2, so that the acid liquid enters the first pre-melting kettle 3 and melts the manually added solid material into a liquid; a second pre-melting kettle 8, which is connected to the acid raw material tank 2, so that the acid liquid enters the second pre-melting kettle 8 and melts the manually added solid material into a liquid; a reactor 4, which is connected to the first pre-melting kettle 3 and the second pre-melting kettle 8 for convenient feeding; a pre-filter 5 and a fine filter 6, which filter the materials in the reactor 4 step by step; a circulation tank 7, which is respectively connected to the fine filter 6 and the reactor 4, and is used to receive the liquid filtered by the fine filter 6, and recycle it into the reactor 4; a flushing tank 17, which is connected to the pre-filter 5, and the flushing agent in it passes through the pre-filter 5 and the fine filter 6 to flush the solid material in the filter; a first flushing tank 9, which is connected to the fine filter 6, and is used to receive a flushing tank 17 after the flushing of the filter by the pre-filter 5 and the fine filter 6 liquid; a second rinsing tank 10, connected to the pre-filter 5, which is used to receive the secondary washing liquid after the first rinsing tank 9 rinses the filter through the pre-filter 5 and the fine filter 6; a homogenizer 11, which is used to add deionized water to dissolve the solids in the pre-filter 5 and the fine filter 6; a condenser 12, connected to the homogenizer 11, which is used to condense the evaporated deionized water in the homogenizer 11 and reflux it into the homogenizer 11; a homogenizer pre-filter 13, a homogenizer fine filter 14, connected to the homogenizer 11 and a coarse product tank 15, which are used to filter the solid-liquid mixture in the homogenizer 11 step by step; the coarse product tank 15, which is used to store the liquid material after step-by-step filtration, a spray dryer 16, connected to the coarse product tank 15, which is used to dry the liquid in the coarse product tank 15 to obtain a precursor product; a steam distributor 18, which is respectively connected to the jackets of the first pre-melting kettle 3, the second pre-melting kettle 8, the reactor 4 and the homogenizer 11 to provide heat.

[0095] In some embodiments, the first pre-melting kettle 3, the second pre-melting kettle 8, the reaction kettle 4 and the homogenizing kettle 11 are all provided with pressure gauges, and the thermometer measures the pressure and temperature in the kettle.

[0096] In some embodiments, each storage tank is provided with a liquid level gauge to measure the liquid level in the tank.

[0097] In some embodiments, the delivery of all liquids in the tank (except for the delivery of acid raw materials by diaphragm pump 1) is carried out by gravity potential energy plus nitrogen pressure.

[0098] In some embodiments, the reactor 4 is respectively connected to the acid raw material tank 2, the first pre-melting reactor 3, the second pre-melting reactor 8, the pre-filter 5 and the circulation tank 7, and is an important component to ensure the circulation of the device. Ball valves are provided at the connections between it and each tank to control the materials entering and leaving the reactor.

[0099] In some embodiments, a thermometer and a pressure gauge are provided on the steam distributor 18 to measure the steam temperature and pressure. Four stop valves are provided on the jacket pipelines connecting the steam distributor to the first pre-melting kettle 3, the second pre-melting kettle 8, the reactor 4 and the homogenizing kettle 11 to control the jacket pressures of the jackets respectively, thereby controlling the jacket temperatures of the jackets. The jackets of the first pre-melting kettle 3, the second pre-melting kettle 8, the reactor 4 and the homogenizing kettle 11 are all provided with pressure gauges to measure the jacket temperatures.

[0100] The present invention is described in detail below by way of examples, but the protection scope of the present invention is not limited to the following description.

[0101] In the following preparation examples, embodiments and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are conventional products that can be obtained through commercial channels.

[0102] In the following examples and comparative examples,

[0103] Battery black powders NCM333, NCM523, NCM622, NCM811, and NCA were purchased from Hebei Sinochem Lithium Battery Technology Co., Ltd.

[0104] The following parameters were measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES).

[0105] Leaching rate: η = (CV / mLi) × 100%; where η is the lithium leaching rate (%); C is the final Li concentration (mg·L -1 ), V is the volume of the initial leaching solution (L), and mLi is the mass of Li in the LiCoO2 powder (mg).

[0106] Precursor loss rate: δ = (1-mS / mL) × 100%; wherein δ is the precursor loss rate (%), mS is the mass of the precursor actually obtained (g); mL is the mass of the precursor theoretically obtained (g).

[0107] Example 1

[0108] A method for preparing a ternary precursor by recycling ternary waste lithium-ion battery black powder using a deep eutectic solvent, using Figure 1 The process diagram shown specifically includes the following steps:

[0109] (1) Put the purchased battery black powder NCM333 into a 150-mesh vibrating screen for screening to obtain a refined black powder of the undersize and a copper-aluminum-plastic mixture of the oversize. The refined black powder is reserved for later use and the oversize is recovered;

[0110] (2) mixing ethylenediamine and formic acid in a molar ratio of 4:1 in a first pre-melting kettle 3, and then heating at 80° C. for 40 min to prepare a deep eutectic solvent;

[0111] (3) 2.5 kg of the refined black powder obtained in step (1) and 100 L of the low eutectic solvent (solid-liquid ratio S:L=25 g / L) obtained in step (2) are placed in a 200 L reactor 4, heated and stirred to 110° C. for 5 h, and the reaction is completed. The solution after the reaction is separated by a pre-filter 5 and a fine filter 6 to obtain a circulating low eutectic solvent and a crude product, and the circulating low eutectic solvent can be placed in the reactor 4 again to react with the refined black powder;

[0112] (4) 80 kg of methanol from the flushing tank 17 is used to flush the crude product in the pre-filter 5 and the fine filter 6, and the residual low eutectic solvent in the crude product is washed away. The obtained primary washing liquid enters the first flushing tank 9; the primary washing liquid in the first flushing tank 9 is used to flush the crude product in the pre-filter 5 and the fine filter 6 again, and the crude precursor product after secondary washing is obtained; the secondary washing liquid enters the second flushing tank 10, and then returns to the reactor 4 through the circulation tank 7;

[0113] (5) The crude precursor obtained in step (4) and 100 kg of deionized water are placed in a homogenizing kettle 11, stirred and heated to 60° C., and then kept at a constant temperature for 0.5 h, and then filtered three times in a homogenizing kettle pre-filter 13 and a homogenizing kettle fine filter 14 to separate the precursor solution and graphite black slag, the graphite black slag is recovered, and the precursor solution is spray-dried in a spray dryer 16 to obtain a precursor solid;

[0114] (6) The precursor solid obtained in step (5) is mixed with the lithium element in the lithium salt in a molar ratio of 1:1.05. The mixed materials are pre-baked at 500° C. for 8 h and then calcined at 1000° C. for 5 h to obtain a positive electrode material.

[0115] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0116] Example 2

[0117] (1) Putting the directly purchased battery black powder NCM523 into a 200-mesh vibrating screen for screening to obtain a refined black powder of the undersize and a copper-aluminum-plastic mixture of the oversize, wherein the refined black powder is reserved for use and the oversize is recovered;

[0118] (2) mixing benzidine and oxalic acid in a molar ratio of 1:2.5 in a first pre-melting kettle 3, and then heating at 60° C. for 60 min to prepare a deep eutectic solvent;

[0119] (3) 2.5 kg of the refined black powder obtained in step (1) and 100 L of the low eutectic solvent (solid-liquid ratio S:L=30 g / L) obtained in step (2) are placed in a 200 L reactor 4, heated and stirred to 115° C. for 4 hours, and the reaction is completed. The solution after the reaction is separated by a pre-filter 5 and a fine filter 6 to obtain a circulating low eutectic solvent and a crude product, and the circulating low eutectic solvent can be placed in the reactor 4 again to react with the refined black powder;

[0120] (4) The 90 kg ethanol from the flushing tank 17 is used to flush the crude product in the pre-filter 5 and the fine filter 6, and the residual low eutectic solvent in the crude product is washed away. The obtained primary washing liquid enters the first flushing tank 9; the primary washing liquid in the first flushing tank 9 is used to flush the crude product in the pre-filter 5 and the fine filter 6 again, and the crude precursor product after secondary washing is obtained; the secondary washing liquid enters the second flushing tank 10, and then returns to the reactor 4 through the circulation tank 7;

[0121] (5) The crude precursor obtained in step (4) and 120 kg of deionized water are placed in a homogenizing kettle 11, stirred and heated to 60° C., and then kept at a constant temperature for 0.5 h, and then filtered three times in a homogenizing kettle pre-filter 13 and a homogenizing kettle fine filter 14 to separate the precursor solution and graphite black slag, the graphite black slag is recovered, and the precursor solution is spray-dried in a spray dryer 16 to obtain a precursor solid;

[0122] (6) The precursor solid obtained in step (5) is mixed with the lithium element in the lithium salt in a molar ratio of 1:1.1. The mixed materials are pre-baked at 800° C. for 3 h and then calcined at 700° C. for 10 h to obtain a positive electrode material.

[0123] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0124] Example 3

[0125] (1) Put the purchased battery black powder NCM622 into a 250-mesh vibrating screen for screening to obtain a refined black powder of the undersize and a copper-aluminum-plastic mixture of the oversize. The refined black powder is reserved for later use and the oversize is recovered;

[0126] (2) triethylenetetramine and terephthalic acid were mixed in a molar ratio of 1:3 in a first pre-melting reactor 3, and then heated at 70° C. for 50 min to prepare a deep eutectic solvent;

[0127] (3) 2.5 kg of the refined black powder obtained in step (1) and 150 L of the low eutectic solvent (solid-liquid ratio S:L=35 g / L) obtained in step (2) were placed in a 200 L reactor 4, heated and stirred to 125° C. for 4.5 hours, and the reaction was completed. The solution after the reaction was separated by a pre-filter 5 and a fine filter 6 to obtain a circulating low eutectic solvent and a crude product, and the circulating low eutectic solvent can be returned to the reactor 4 again to react with the refined black powder;

[0128] (4) 100 kg of propanol from the washing storage tank 17 is used to wash the crude product in the pre-filter 5 and the fine filter 6 to wash away the residual low eutectic solvent in the crude product, and the obtained primary washing liquid enters the first washing tank 9; the primary washing liquid in the first washing tank 9 is used to wash the crude product in the pre-filter 5 and the fine filter 6 again to obtain a crude precursor product after secondary washing; the secondary washing liquid enters the second washing tank 10, and then returns to the reactor 4 through the circulation tank 7; (5) The crude precursor product obtained in step (4) and 100 kg of deionized water are placed in a homogenizing kettle 11, stirred and heated to 60°C and kept at a constant temperature for 0.5 h, and then filtered three times in the homogenizing kettle pre-filter 13 and the homogenizing kettle fine filter 14 to separate the precursor solution and graphite carbon black slag, the graphite carbon black slag is recovered, and the precursor solution is spray-dried in a spray dryer 16 to obtain a precursor solid;

[0129] (6) The precursor solid obtained in step (5) is mixed with the lithium element in the lithium salt in a molar ratio of 1:1.5. The mixed materials are pre-baked at 700° C. for 6 h and then calcined at 900° C. for 8 h to obtain a positive electrode material.

[0130] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0131] Example 4

[0132] The method of Example 1 is different in that, in step (2), the mixing of ethylenediamine and formic acid in a molar ratio of 4:1 in the first pre-melting kettle 3 is replaced by mixing benzidine and formic acid in a molar ratio of 4:1 in the first pre-melting kettle 3.

[0133] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0134] Example 5

[0135] The method of Example 1 is followed, except that in step (2), the mixture of ethylenediamine and benzidine (the molar ratio of ethylenediamine to benzidine is 1:2.5) and formic acid at a molar ratio of 4:1 is mixed in the first pre-melting kettle 3 instead of being mixed with benzidine and formic acid at a molar ratio of 4:1 in the first pre-melting kettle 3.

[0136] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0137] Comparative Example 1

[0138] The method of Example 1 is different in that the first flushing tank 9 is omitted, that is, 100 kg of methanol from the flushing tank 17 is used to flush the crude product in the pre-filter 5 and the fine filter 6 to wash away the low eutectic solvent remaining in the crude product, thereby obtaining a crude precursor product after one washing; the washing liquid after one washing enters the second flushing tank 10, and then returns to the reactor 4 through the circulation tank 7.

[0139] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0140] Comparative Example 2

[0141] The method of Example 1 is followed, except that the fine filter 6 is omitted, that is, the solution after the reaction is separated only by the pre-filter 5 to obtain a circulating deep eutectic solvent and a crude product.

[0142] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0143] Comparative Example 3

[0144] The method of Example 1 is followed, except that in step (2), ethylenediamine and phenol are mixed in a first pre-melting kettle 3 at a molar ratio of 4:1, and then heated at 80° C. for 40 min to prepare a low eutectic solvent.

[0145] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0146] Comparative Example 4

[0147] The method of Example 1 is followed, except that in step (2), formamide and formic acid are mixed in a first pre-melting kettle 3 at a molar ratio of 4:1, and then heated at 80° C. for 40 min to prepare a low eutectic solvent.

[0148] After testing, the leaching rate and precursor loss rate are shown in Table 1.

[0149] Table 1

[0150] serial number Solid-liquid ratio Leaching rate (%) Precursor loss rate (%) Example 1 2.5kg:100L 92.3％ 1.83％ Example 2 3.0kg:100L 91.8％ 2.04％ Example 3 3.5kg:100L 92.1％ 1.99％ Example 4 2.5kg:100L 91.1％ 2.11％ Example 5 2.5kg:100L 94.9％ 1.2％ Comparative Example 1 2.5kg:100L 76.1％ 6.68％ Comparative Example 2 2.5kg:100L 62.5％ 10.2％ Comparative Example 3 2.5kg:100L 50.9％ 15.2％ Comparative Example 4 2.5kg:100L 78.6％ 7.63％

[0151] It can be seen from the results in Table 1 that the use of Example 1 has a significantly better effect of high leaching rate and low precursor loss rate.

[0152] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A device for preparing a ternary precursor from waste lithium-ion batteries, characterized in that: The device comprises: at least one pre-melting kettle for dissolving the solvent to form a liquid solvent; A reaction kettle connected to the pre-melting kettle, used to leach the black powder of waste lithium-ion batteries with the liquid solvent from the pre-melting kettle to obtain a solid-liquid mixture; A pre-filter, connected to the reactor, for preliminary filtering of the solid-liquid mixture; A fine filter, connected to the pre-filter, for fine filtering the liquid phase after preliminary filtration by the pre-filter; at least one washing tank connected to the pre-filter and the fine filter for washing the crude product after being filtered by the pre-filter and the fine filter; A homogenizing kettle is used to purify the washed crude product by adding water to obtain a mixture; A homogenizing kettle pre-filter, connected to the homogenizing kettle, for preliminarily filtering the mixture from the homogenizing kettle; A homogenizing kettle fine filter is connected to the homogenizing kettle pre-filter and is used to finely filter the liquid phase filtered by the homogenizing kettle pre-filter to obtain a precursor solution; A crude product tank, connected to the homogenizing kettle fine filter, for storing the precursor solution; A spray dryer is connected to the product tank and is used to dry the precursor solution to obtain a ternary precursor.

2. The device according to claim 1, wherein: The pre-melting kettle comprises a first pre-melting kettle and a second pre-melting kettle; the first pre-melting kettle is used to provide liquid solvent to the reaction kettle; the second pre-melting kettle is a supplementary kettle, used to supplement liquid solvent to the reaction kettle.

3. The device according to claim 1 or 2, wherein: The flushing tank comprises a flushing storage tank, a first flushing tank and a second flushing tank; The flushing storage tank is connected to the pre-filter and the fine filter in sequence, and is used to store the flushing agent and flush the materials in the pre-filter and the fine filter; The first flushing tank is connected to the fine filter and is used to receive the primary washing liquid after the pre-filter and the fine filter are flushed with the flushing agent in the flushing storage tank; the second flushing tank is connected to the pre-filter and is used to receive the secondary washing liquid after the pre-filter and the fine filter are flushed with the primary washing liquid in the first flushing tank.

4. The device according to any one of claims 1 to 3, wherein: The device also includes: an acid raw material tank, connected to the reaction kettle and the pre-melting kettle, and used to provide acid liquid to the reaction kettle and the pre-melting kettle; A diaphragm pump is connected to the acid raw material tank and is used to add material to the acid raw material tank.

5. The device according to any one of claims 1 to 4, wherein: The device also includes: A circulation tank is connected to the fine filter and the reactor, and is used to receive the liquid filtered by the fine filter and return it to the reactor.

6. The device according to any one of claims 1 to 5, wherein: The device also includes: A heat exchanger connected to the homogenizing kettle and used for refluxing the water vapor volatilized from the homogenizing kettle; A steam distributor is connected to the jackets of the pre-melting kettle, the reaction kettle and the homogenizing kettle, and is used to provide heat for the pre-melting kettle, the reaction kettle and the homogenizing kettle.

7. A method for preparing a ternary precursor using waste lithium-ion batteries, characterized in that: The method comprises: (1) first mixing the polyamino-containing substance with an acid solution to obtain a deep eutectic solvent; wherein the acid solution is selected from at least one of reducing organic carboxylic acids; (2) performing a second mixing of the low eutectic solvent and the refined black powder of waste lithium ion batteries, and performing a first separation to obtain a crude product and a low eutectic solvent; (3) washing the crude product with an alcohol; then mixing the washed crude product with deionized water for a third time; obtaining a precursor solution and a graphite mixture through a second separation; then drying the precursor solution to obtain a precursor; (4) The precursor is mixed with a lithium salt and then calcined to obtain a positive electrode material.

8. The method according to claim 7, wherein: The polyamino-containing substance is selected from at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, benzidine, 4,4'-diamino-3,3'-dimethylbiphenyl, dianisidine, 2,6-diaminoanthracene and 4,4'-diaminoterphenyl; preferably, the polyamino-containing substance is selected from ethylenediamine and benzidine, and the molar ratio of the two is 1:2-8; And / or, in step (1), the molar ratio of the polyamino-containing substance to the acid solution is (1-5):(1-15); And / or, in step (1), the molar concentration of the reducing organic carboxylic acid in the polyvalent deep eutectic solvent is 0.2-15 mol / L.

9. The method according to claim 7 or 8, wherein: The reducing organic carboxylic acid is selected from at least one of aliphatic carboxylic acid, alicyclic carboxylic acid and aromatic carboxylic acid; Preferably, the aliphatic carboxylic acid is selected from at least one of formic acid, lactic acid, methanesulfonic acid, acetic acid, oxalic acid, propionic acid, malonic acid, butyric acid, maleic acid, tartaric acid, fumaric acid, adipic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, ricinoleic acid, citric acid and malic acid; Preferably, the alicyclic carboxylic acid is selected from at least one of cyclopropylacetic acid, cyclobutaneacetic acid, cyclopentaneacetic acid, cyclohexaneacetic acid, cyclopentanecarboxylic acid and 1,3,5-cyclohexanetric acid; Preferably, the aromatic carboxylic acid is at least one selected from benzoic acid, p-toluenesulfonic acid, phthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, 2,6-naphthalene dicarboxylic acid and cinnamic acid.

10. The method according to any one of claims 7 to 9, wherein: In step (2), the solid-liquid ratio of the refined black powder and the low eutectic solvent is 1g:(10-100)L; And / or, in step (3), the solid-liquid ratio of the washed crude product to deionized water is 1 g:(10-100) L; And / or, in step (4), the amount of the lithium salt added is 1-1.5 times the amount of the missing lithium element, calculated as lithium element.

11. The method according to any one of claims 7 to 10, wherein: In step (1), the temperature of the first mixing is 60-80°C and the time is 20-60min; And / or, in step (2), the temperature of the second mixing is 100-150° C. and the time is 2-6 h; And / or, in step (3), the temperature of the third mixing is 60-90° C. and the time is 0.5-2 h; And / or, in step (4), the calcination conditions include: first calcining at 500-800° C. for 3-8 h; Then calcine at 700-1000℃ for 5-12h.

12. The method according to any one of claims 7 to 11, wherein: In step (2), the refined black powder of waste lithium-ion batteries is the screened material obtained by screening the lithium battery black powder using a 100-300 mesh screening machine; Preferably, the method for preparing the lithium battery black powder comprises: discharging the waste lithium-ion battery, placing it in the air for disassembly, and then crushing the positive and negative electrode sheets.

Images