WO2025000270A1 - Method for full-chain integrated treatment of spent ternary lithium batteries - Google Patents

Abstract

The present disclosure belongs to the technical field of recycling of spent batteries. Disclosed is a method for full-chain integrated treatment of spent ternary lithium batteries. The method comprises the following steps: subjecting black mass in a spent ternary lithium battery to be treated and a reducing agent to first roasting, so as to obtain a first roasted product; subjecting the first roasted product to a lithium extraction treatment, and subjecting lithium-extracted residues obtained by means of the lithium extraction treatment to magnetic separation; subjecting a non-magnetic material obtained by means of the magnetic separation to first acid leaching and solid-liquid separation, so as to obtain first acid leaching residues; subjecting the first acid leaching residues to second roasting, so as to obtain a second roasted product; and subjecting graphite in the second roasted product to flotation. The method can at least efficiently recycle graphite in spent ternary lithium batteries, thereby avoiding the wasting of resources.

Description

A method for processing waste ternary lithium batteries in an integrated manner Technical Field

The present disclosure relates to the technical field of waste battery recycling, and in particular to a method for processing waste ternary lithium batteries in an integrated manner throughout the entire chain.

Background Art

With the rapid development of the new energy vehicle industry in recent years, the production and demand of lithium-ion batteries have been growing day by day. However, waste lithium-ion batteries contain a large amount of heavy metals and organic matter. If they are not recycled, they will cause great pollution to the environment and endanger human survival. The effective and green recycling of waste lithium batteries can not only solve environmental problems, but also create greater economic benefits by recycling the valuable components of waste lithium batteries.

The traditional recycling process of waste ternary lithium batteries is mainly divided into pyrometallurgical process and hydrometallurgical process. The pyrometallurgical process is to melt the waste lithium batteries at high temperature to generate metal alloys, and then use wet process or electrolytic process to obtain products from the alloys; the wet process is to disassemble, crush and screen the waste ternary lithium batteries to obtain black powder, and then leach, remove impurities and extract the black powder.

However, whether it is a pyrometallurgical process or a hydrometallurgical process, it is difficult to effectively recycle the graphite in waste ternary lithium batteries.

In view of this, the present disclosure is proposed.

Summary of the invention

The purpose of the present disclosure includes providing a method for processing waste ternary lithium batteries in an integrated manner, which can at least effectively recycle graphite in waste ternary lithium batteries and avoid waste of resources.

The present disclosure can be implemented as follows:

The present invention provides a method for processing waste ternary lithium batteries in an integrated manner, comprising the following steps:

The battery black powder in the waste ternary lithium battery to be treated is first roasted with a reducing agent to obtain a first roasted product; the first roasted product is subjected to lithium extraction treatment, and the lithium extraction slag obtained by the lithium extraction treatment is subjected to magnetic separation; the non-magnetic material separated by magnetic separation is subjected to a first acid leaching, solid-liquid separation, and a first acid leaching slag is obtained; the first acid leaching slag is second roasted to obtain a second roasted product with amorphous carbon removed; and graphite in the second roasted product is floated.

In an optional embodiment, the reducing agent includes at least one of coal powder, carbon powder and an organic carbon reducing agent;

And/or, the mass ratio of battery black powder to reducing agent is 100:2-100:15.

In an optional embodiment, the first roasting includes at least one of the following features:

Feature 1: The first roasting is carried out under oxygen-free conditions;

Feature 2: The temperature of the first calcination is 500℃-800℃;

Feature 3: The first roasting time is 30min-240min.

In an optional embodiment, the lithium extraction treatment includes: first subjecting the first roasted product to water leaching for lithium, and then subjecting the solid obtained by water leaching for lithium to acid leaching.

In an optional embodiment, during the water leaching of lithium, the mass ratio of the first calcined product to water is 1:3-1:15; and/or the time for water leaching of lithium is 10 min-120 min.

In an optional embodiment, the acid leaching lithium process includes at least one of the following features:

Feature 1: The acid used for acid leaching of lithium includes sulfuric acid;

Feature 2: The concentration of the acid used in the acid leaching process is 10g/L-100g/L, and the mass ratio of the acid used in the acid leaching process to the solid matter extracted by water leaching is 2:1-6:1;

Feature 3: The time for acid leaching of lithium is 10min-100min.

In an optional embodiment, the magnetic separation includes at least one of the following features:

Feature 1: Magnetic separation is carried out in magnetic separation columns;

Feature 2: The magnetic field strength used for magnetic separation is 2000GS-12000GS;

Feature 3: Magnetic separation is carried out in the presence of water, with a water volume of 10L/h-100L/h.

In an optional embodiment, the first acid leaching includes: pressurizing the non-magnetic material with a first acid and a first oxidant for leaching.

In an optional embodiment, the first acid leaching process includes at least one of the following features:

Feature 1: The first acid includes sulfuric acid;

Feature 2: The mass ratio of the non-magnetic material to the first acid is 1:2-1:5, and the concentration of the first acid is 150g/L-400g/L;

Feature 3: The amount of the first oxidant is 0.5 to 3 times the molar amount of the metal contained in the non-magnetic material;

Feature 4: The first oxidant includes at least one of hydrogen peroxide, sodium sulfite and sodium thiosulfate;

Feature 5: The pressure of the first acid leaching is 0.4MPa-1.5MPa;

Feature 6: The first acid leaching time is 20min-120min.

In an optional embodiment, the second roasting includes at least one of the following features:

Feature 1: The second roasting is carried out under oxygen conditions;

Feature 2: The temperature of the second calcination is 300℃-550℃;

Feature 3: The second roasting time is 30min-180min.

In an alternative embodiment, flotation is performed in a flotation column.

In an optional embodiment, the floated graphite is repaired to obtain battery-grade graphite.

In an optional embodiment, the repair process includes: coating the graphite with a carbonaceous material, followed by high temperature carbonization. change.

In an alternative embodiment, the carbonaceous material includes at least one of asphalt, glucose, and sucrose.

In an optional embodiment, the amount of carbon-containing material used is 2 wt%-15 wt% of the graphite.

In an optional embodiment, the temperature of the high temperature carbonization is 800° C.-1500° C., and/or the time of the high temperature carbonization is 30 min-240 min; and/or the high temperature carbonization is performed in an oxygen-free atmosphere.

In an optional embodiment, the method further includes purifying the graphite before repairing.

In an alternative embodiment, the reagents used for purification include hydrochloric acid and nitric acid.

In an optional embodiment, the lithium extraction solution obtained by the lithium extraction process is subjected to lithium precipitation treatment to obtain a lithium-containing product.

In an optional embodiment, the magnetic material obtained by magnetic separation is subjected to a second acid leaching, solid-liquid separation, to obtain a second acid leaching solution; the second acid leaching solution is extracted and impurities are removed to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate.

In an optional embodiment, the second acid leaching includes: leaching the magnetic material with a second acid and a second oxidant at normal pressure.

In an optional embodiment, the second pickling process includes at least one of the following features:

Feature 1: The second acid includes sulfuric acid;

Feature 2: The mass ratio of the magnetic material to the second acid is 1:2-1:5, and the concentration of the second acid is 150g/L-400g/L;

Feature 3: The amount of the second oxidant is 0.5 to 3 times the molar amount of the metal contained in the magnetic material;

Feature 4: The second oxidant includes at least one of hydrogen peroxide, sodium sulfite and sodium thiosulfate;

Feature 5: The second acid leaching time is 30min-240min.

In an optional embodiment, the extraction reagent used in the extraction of the second acid leaching solution includes at least one of 2-ethylhexyl mono-2-ethylhexyl phosphate, di(2-ethylhexyl) phosphate and di(2,4,4-trimethylpentyl)phosphinic acid.

In an optional embodiment, the first acid leaching liquid obtained after the first acid leaching is subjected to impurity removal and extraction to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate.

In an optional embodiment, the extraction reagent used in the extraction of the first acid leaching solution includes at least one of 2-ethylhexyl mono-2-ethylhexyl phosphate, di(2-ethylhexyl) phosphate and di(2,4,4-trimethylpentyl)phosphinic acid.

The beneficial effects of the present disclosure include: the present disclosure obtains a first roasting product by first roasting the battery black powder in the waste ternary lithium battery to be processed with a reducing agent; performs lithium extraction treatment on the first roasting product, and performs magnetic separation on the lithium extraction slag obtained by the lithium extraction treatment; performs a first acid leaching on the non-magnetic material separated by magnetic separation, and performs solid-liquid separation to obtain a first acid leaching slag; performs a second roasting on the first acid leaching slag to obtain a second roasting product; and floats the graphite in the second roasting product. The method can at least efficiently recover graphite in waste ternary lithium batteries and avoid waste of resources.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

FIG1 is a process flow chart of the method for processing waste ternary lithium batteries in an integrated manner in Example 1;

FIG. 2 is a SEM image of the battery-grade graphite product obtained in Example 1.

DETAILED DESCRIPTION

In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the technical scheme in the embodiments of the present disclosure will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

The following is a detailed description of the full-chain integrated method for processing waste ternary lithium batteries provided by the present invention.

The present disclosure proposes a method for processing waste ternary lithium batteries in an integrated manner, which may include the following steps: subjecting the battery black powder in the waste ternary lithium batteries to be processed to a first roasting with a reducing agent to obtain a first roasting product; subjecting the first roasting product to a lithium extraction process, and subjecting the lithium extraction slag obtained by the lithium extraction process to a magnetic separation process; subjecting the non-magnetic material separated by the magnetic separation to a first acid leaching process, and performing solid-liquid separation to obtain a first acid leaching slag; subjecting the first acid leaching slag to a second roasting process, and obtaining a second roasting product; and flotating the graphite in the second roasting product.

For reference, the above-mentioned waste ternary lithium batteries mainly refer to waste nickel-cobalt-manganese ternary lithium batteries, and the battery black powder can be obtained by discharging, crushing, cracking and screening the waste ternary lithium batteries to be processed. Exemplarily, the main components of the battery black powder include ternary positive electrode materials, graphite negative electrode materials, conductive agents, binders and a small amount of current collectors (such as copper foil, aluminum foil, etc.).

In the present disclosure, the reducing agent used may illustratively but not limitatively include at least one of coal powder, carbon powder and organic carbon reducing agent.

The mass ratio of battery black powder to reducing agent can be 100:2-100:15, such as 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14 or 100:15, etc., or any other value within the range of 100:2-100:15. In some embodiments, the mass ratio of battery black powder to coal powder is 100:6.

In the present disclosure, the first calcination is performed under oxygen-free conditions, for example, under inert gas conditions or nitrogen conditions.

The temperature of the first calcination may be 500° C.-800° C., such as 500° C., 550° C., 600° C., 650° C., 700° C., 750° C. or 800° C., or any other value within the range of 500° C.-800° C. In some embodiments, the temperature of the first calcination is 650° C.

The time of the first roasting can be 30min-240min, such as 30min, 50min, 80min, 100min, 120min, 150min, 180min, 200min, 220min or 240min, etc., or any other value within the range of 30min-240min. In some embodiments, the time of the first roasting is 180min.

As mentioned above, by reducing and roasting the battery black powder with a reducing agent (first roasting), most of the nickel and most of the cobalt in the battery black powder can be reduced to magnetic nickel and cobalt, which is beneficial for subsequent magnetic separation to obtain magnetic metal substances and non-magnetic graphite and other substances, avoiding the influence of nickel and cobalt on the subsequent separation of graphite. In addition, the lithium contained in the battery black powder can form lithium-containing carbonates during the first roasting process, which is beneficial for effective leaching in the lithium extraction process, avoiding the influence of lithium on the subsequent separation of graphite. It should be noted that manganese is still in the form of oxide at the first roasting temperature and will not be reduced to a single substance.

In the present disclosure, the lithium extraction process includes: first subjecting the first roasted product to water leaching for lithium, and then subjecting the solid obtained by water leaching for lithium to acid leaching.

For reference, during the water leaching of lithium, the mass ratio of the first calcined product to water can be 1:3-1:15, such as 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14 or 1:15, or any other value within the range of 1:3-1:15. In some embodiments, the mass ratio of the first calcined product to water is 1:12.

The time for water leaching lithium can be 10 min-120 min, such as 10 min, 20 min, 40 min, 60 min, 80 min, 100 min or 120 min, etc., or any other value within the range of 10 min-120 min. In some embodiments, the time for water leaching lithium is 90 min.

By carrying out water leaching of lithium under the above conditions, most of the lithium can be leached out, and the purity of the leached lithium is relatively high, which is beneficial to reducing the subsequent impurity removal costs.

For reference, the acid used in the acid leaching process of lithium includes sulfuric acid and the like.

The concentration of the acid used in the acid leaching process can be 10g/L-100g/L, such as 10g/L, 20g/L, 30g/L, 40g/L, 50g/L, 60g/L, 70g/L, 80g/L, 90g/L or 100g/L, etc., or any other value within the range of 10g/L-100g/L. In some embodiments, the concentration of the acid used in the acid leaching process is 60g/L.

The mass ratio of the acid used in the acid leaching process to the solids extracted by water leaching can be 2:1-6:1, such as 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1 or 6:1, or any other value within the range of 2:1-6:1. In some embodiments, the mass ratio of the acid used in the acid leaching process to the solids extracted by water leaching is 1:3.

The time for acid leaching lithium can be 10 min-100 min, such as 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min or 100 min, etc., or any other value within the range of 10 min-100 min. In some embodiments, the time for acid leaching lithium is 60 min.

By acid leaching lithium under the above conditions, the lithium remaining in the solid matter obtained by water leaching can be further effectively extracted.

As mentioned above, by first leaching lithium with water, most of the lithium can be selectively leached, and nickel, cobalt and manganese will not be leached in this process; then by acid leaching lithium, the lithium that has not been leached in the lithium leaching stage can be further leached (since the concentration of the acid used in the acid leaching process is low, nickel, cobalt and manganese will basically not be leached). Extracting lithium by first leaching with water and then leaching with acid can obtain a higher lithium leaching rate.

In the present disclosure, the lithium extraction slag obtained by the lithium extraction treatment is the leached slag obtained after the above-mentioned acid leaching lithium extraction treatment, and the leached slag includes magnetic materials (such as nickel, cobalt, manganese, etc.) and non-magnetic materials (such as graphite and non-magnetic oxides of nickel, cobalt and manganese).

For reference, the magnetic separation of the magnetic material and the non-magnetic material can be carried out in a magnetic separation column.

The magnetic field strength used for magnetic separation can be 2000GS-12000GS, such as 2000GS, 4000GS, 6000GS, 8000GS, 10000GS or 12000GS, or any other value within the range of 2000GS-12000GS. In some embodiments, the magnetic field strength used for magnetic separation is 10000GS.

Magnetic separation is carried out in the presence of water, that is, the leached residue obtained after acid leaching of lithium is mixed with water and then subjected to magnetic separation. Exemplarily, the amount of water used in the magnetic separation process can be 10L/h-100L/h, such as 10L/h, 20L/h, 30L/h, 40L/h, 50L/h, 60L/h, 70L/h, 80L/h, 90L/h or 100L/h, etc., or any other value within the range of 10L/h-100L/h. In some embodiments, the amount of water used in the magnetic separation process is 60L/h.

As mentioned above, through the above magnetic separation, the magnetic field of the magnetic separation column and the gravity separation washing can effectively separate the magnetic material and the non-magnetic material. The magnetic material is mainly nickel, cobalt and manganese, and the impurity content in the leaching solution of the magnetic material is greatly reduced. In addition to graphite, the non-magnetic material also contains some nickel and cobalt (such as nickel oxide, cobalt oxide) that have not been reduced to a single substance, as well as manganese oxide, etc.

In the present disclosure, the first acid leaching includes: pressurizing and leaching the non-magnetic material with a first acid and a first oxidant.

The first acid used in this process includes sulfuric acid and the like.

The mass ratio of the non-magnetic material to the first acid can be 1:2-1:5, such as 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, etc., or any other value within the range of 1:2-1:5. In some embodiments, the mass ratio of the non-magnetic material to the first acid is 1:3.

The concentration of the first acid can be 150 g/L-400 g/L, such as 150 g/L, 200 g/L, 250 g/L, 300 g/L, 350 g/L or 400 g/L, or any other value within the range of 150 g/L-400 g/L. In some embodiments, the concentration of the first acid is 200 g/L.

The amount of the first oxidant can be 0.5 times to 3 times the molar amount of the metal contained in the non-magnetic material, such as 0.5 times, 1 times, 1.5 times, 2 times, 2.5 times or 3 times, or any other value within the range of 0.5 times to 3 times. In some embodiments, the amount of the first oxidant is 1.2 times the molar amount of the metal contained in the non-magnetic material.

The first oxidant may illustratively include at least one of hydrogen peroxide, sodium sulfite and sodium thiosulfate.

For reference, the pressure of the first acid leaching may be 0.4 MPa-1.5 MPa, such as 0.4 MPa, 0.5 MPa, 0.8 MPa, 1.0 MPa, 1.2 MPa or 1.5 MPa, etc., or any other value within the range of 0.4 MPa-1.5 MPa. In some embodiments, the pressure of the first acid leaching is 1 MPa.

The first acid leaching time may be 20 min-120 min, such as 20 min, 40 min, 60 min, 80 min, 100 min or 120 min, etc., or any other value within the range of 20 min-120 min. In some embodiments, the first acid leaching time is 90 min.

After the first acid leaching, the solid and liquid are separated to obtain the first acid leaching residue and the first acid leaching liquid. The first acid leaching residue is mainly composed of graphite residue, and also contains a small amount of metal elements such as nickel and cobalt and their oxides that are not completely leached. The first acid leaching liquid is mainly composed of nickel, cobalt, and manganese, such as nickel sulfate, cobalt sulfate, and manganese sulfate.

As mentioned above, by subjecting the non-magnetic material to pressurized acid leaching according to the above conditions, most of the nickel, cobalt and manganese in the non-magnetic material can be leached, and it is beneficial to accelerate the leaching reaction rate and reduce the leaching time.

In some embodiments, the first acid leaching solution obtained by the first acid leaching may be further subjected to impurity removal and extraction to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate.

For reference, the extraction reagent used in the first acid leaching solution for extraction may exemplarily include at least one of 2-ethylhexyl phosphate mono-2-ethylhexyl ester (i.e., extractant P507), di(2-ethylhexyl) phosphate (i.e., extractant P204), and di(2,4,4-trimethylpentyl)phosphinic acid (i.e., extractant C272). In some embodiments, the first acid leaching solution may be extracted using the above extraction reagents for step-by-step extraction.

It should be noted that if the first acid leaching residue is directly subjected to flotation, it is difficult to effectively separate the graphite and amorphous carbon (such as coal powder in the conductive agent and the reducing agent) in the first acid leaching residue, and the oxidation temperature of graphite is higher than that of amorphous carbon. Therefore, the present disclosure first performs a second roasting on the first acid leaching residue and then performs flotation.

For reference, the second calcination is performed under aerobic conditions, such as air conditions or oxygen conditions.

The temperature of the second calcination may be 300° C.-550° C., such as 300° C., 350° C., 400° C., 450° C., 500° C. or 550° C., or any other value within the range of 300° C.-550° C. In some embodiments, the temperature of the second calcination is 450° C.

The second calcination time is 30 min-180 min, such as 30 min, 50 min, 80 min, 100 min, 120 min, 150 min or 180 min, etc., or any other value within the range of 30 min-180 min. In some embodiments, the second calcination time is 120 min.

In line with the above, by performing the second roasting under the above conditions, the amorphous carbon in the first acid leaching residue can be effectively removed, which is beneficial to improving the quality of the subsequent graphite concentrate. In addition, a small amount of metal elements and oxides such as nickel and cobalt that are not completely leached after the first acid leaching can be formed into metal oxides that are more easily reacted with acid (such as sulfuric acid) through the second roasting, which is beneficial to the subsequent purification. Remove impurities.

In the present disclosure, flotation can be carried out in a flotation column, and the flotation reagents used for flotation include a collector, a frother and a regulator. Among them, the collector includes kerosene or diesel, and its dosage can be 300g/t for example; the frother includes pine oil or octanol, and its dosage can be 120g/t for example; the regulator includes water glass or sodium hexametaphosphate, and its dosage can be 1000g/t for example.

It should be noted that the flotation column used in the present disclosure has the following advantages over the conventional flotation machine: the graphite product obtained by the flotation column has a higher grade and a higher recovery rate.

The above flotation is beneficial to the recovery of fine-grained graphite and the improvement of the graphite recovery rate.

Furthermore, the floated graphite can be repaired to obtain battery-grade graphite.

For reference, the repair process may include coating graphite with a carbonaceous substance followed by high temperature carbonization.

The carbon-containing material may illustratively include at least one of asphalt, glucose and sucrose. In some embodiments, the carbon-containing material is asphalt.

Exemplarily, the amount of the carbon-containing substance can be 2wt%-15wt% of the graphite, such as 2wt%, 5wt%, 8wt%, 10wt%, 12wt% or 15wt%, etc., or any other value within the range of 2wt%-15wt%. In some embodiments, the amount of the carbon-containing substance is 6wt% of the graphite.

The temperature of high temperature carbonization may be 800° C.-1500° C., such as 800° C., 900° C., 1000° C., 1100° C., 1200° C., 1300° C., 1400° C. or 1500° C., or any other value within the range of 800° C.-1500° C. In some embodiments, the temperature of high temperature carbonization is 1200° C.

The high temperature carbonization time can be 30 min-240 min, such as 30 min, 50 min, 80 min, 100 min, 120 min, 150 min, 180 min, 200 min, 220 min or 240 min, etc., or any other value within the range of 30 min-240 min. In some embodiments, the high temperature carbonization time is 120 min.

The high temperature carbonization is performed in an oxygen-free atmosphere (such as an inert atmosphere or a nitrogen atmosphere).

As mentioned above, by coating graphite with carbon-containing substances and then carbonizing it at high temperature, a battery-grade graphite product can be directly obtained, thus avoiding the high cost of graphitizing graphite at conditions above 2500°C in the prior art.

In some embodiments, the graphite may be purified prior to being remediated.

For reference, the purification reagents used for purification may include hydrochloric acid and nitric acid.

Among them, the mass ratio of the purification reagent to graphite can be 2:1, the concentration of hydrochloric acid can be 200 g/L, the concentration of nitric acid can be 200 g/L, and the purification time can be 100 min.

Through purification to remove the remaining impurities contained in the graphite, the purity of the purified graphite can be as high as 99.9%.

Furthermore, in order to realize the recycling of all components of waste ternary lithium batteries, the lithium extraction process can also be used to The obtained lithium extraction solution is subjected to lithium precipitation treatment to obtain a lithium-containing product.

The lithium extraction solution obtained by the above lithium extraction treatment is the leaching solution obtained after the acid leaching lithium treatment, and the main component of the leaching solution is lithium.

The precipitated lithium can be recovered by adding carbon dioxide or sodium carbonate to the lithium extraction solution and heating it for precipitation.

Furthermore, in order to realize the recycling of all components of waste ternary lithium batteries, in the present disclosure, the magnetic material obtained by magnetic separation can also be subjected to a second acid leaching, solid-liquid separation, to obtain a second acid leaching solution, and the second acid leaching solution can be extracted and impurities removed to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate.

For reference, the second acid leaching includes: leaching the magnetic material with a second acid and a second oxidant at normal pressure (such as one atmosphere).

The second acid used in this process includes sulfuric acid and the like.

The mass ratio of the magnetic material to the second acid can be 1:2-1:5, such as 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, etc., or any other value within the range of 1:2-1:5. In some embodiments, the mass ratio of the magnetic material to the second acid is 1:4.

The concentration of the second acid can be 150 g/L-400 g/L, such as 150 g/L, 200 g/L, 250 g/L, 300 g/L, 350 g/L or 400 g/L, etc., or any other value within the range of 150 g/L-400 g/L. In some embodiments, the concentration of the second acid is 300 g/L.

The amount of the second oxidant can be 0.5 to 3 times the molar amount of the metal contained in the magnetic material, such as 0.5, 1, 1.5, 2, 2.5 or 3 times, or any other value within the range of 0.5 to 3 times. In some embodiments, the amount of the second oxidant is 1.5 times the molar amount of the metal contained in the magnetic material.

The second oxidant may illustratively include at least one of hydrogen peroxide, sodium sulfite and sodium thiosulfate.

For reference, the second acid leaching time may be 30 min-240 min, such as 30 min, 50 min, 80 min, 100 min, 120 min, 150 min, 180 min, 200 min, 220 min or 240 min, etc., or any other value within the range of 30 min-240 min. In some embodiments, the second acid leaching time is 180 min.

As mentioned above, by subjecting the magnetic material to a second acid leaching, the risk of hydrogen generated when nickel metal element and cobalt metal element react with sulfuric acid can be avoided.

For reference, the extraction reagent used in the second acid leaching solution for extraction may exemplarily include at least one of P507, P204 and C272. In some embodiments, the second acid leaching solution may be extracted by using the above extraction reagents for stepwise extraction.

Based on the above, the general process and principle of the above method provided by the present disclosure can be summarized as follows:

The invention discloses a method of first calcining battery black powder and a reducing agent (oxygen-free calcination), then extracting lithium by water leaching and acid leaching, recovering lithium in the lithium extraction solution obtained by lithium precipitation, and subjecting the lithium extraction slag obtained by lithium extraction to a magnetic separation column. Magnetic separation is performed to separate magnetic materials and non-magnetic materials. The magnetic material is subjected to a second acid leaching (acid leaching with an oxidant at normal pressure) to obtain a second acid leaching solution, and the second acid leaching solution is subjected to extraction and impurity removal to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate. The non-magnetic material is subjected to a first acid leaching (acid leaching with an oxidant at pressure) to obtain a first leachate, and the first leachate is subjected to impurity removal and extraction to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate. The first leaching residue is subjected to a second roasting (low-temperature aerobic roasting) to remove amorphous carbon and residual organic matter, and then a primary graphite product is obtained by flotation column flotation. After the primary graphite product is purified and refined, carbon-containing substances (such as asphalt) are added for coating, and then battery-grade graphite is obtained by high-temperature carbonization. This method can achieve full resource utilization of valuable components of battery black powder.

For reference, the corresponding lithium recovery rate of this method can be greater than 94%, the recovery rate of nickel and cobalt can be greater than 97%, the recovery rate of manganese can be greater than 96%, and the recovery rate of battery-grade graphite products can be greater than 80%.

The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

Example 1

This embodiment provides a method for processing waste ternary lithium batteries in an integrated manner. Referring to FIG. 1 , the method includes the following steps:

S1: The waste nickel-cobalt-manganese ternary lithium batteries recycled by a company in Hunan are discharged, crushed, cracked and sieved to obtain battery black powder.

S2: After the battery black powder and the coal powder are mixed evenly, a first roasting treatment is performed to obtain a first roasting product.

During the first calcination process, inert gas (argon) was passed to maintain an oxygen-free environment, the amount of coal powder added was 6wt% of the battery black powder, the temperature of the first calcination was 650°C, and the time of the first calcination was 180min.

S3: placing the first calcined product into a container for water leaching of lithium, and performing solid-liquid separation to obtain a solid.

The mass ratio of the first roasted product to water is 1:12, and the time for water leaching lithium is 90 minutes.

S4: The solid obtained by leaching lithium with water is mixed with sulfuric acid to carry out acid leaching of lithium, and the solid-liquid separation is carried out to obtain leaching residue and leaching liquid.

The mass ratio of the solid matter extracted by sulfuric acid and water leaching used in the acid leaching process is 1:3, the concentration of sulfuric acid is 60g/L, and the time for acid leaching lithium is 60min.

S5: introducing carbon dioxide into the above leaching solution, heating and precipitating, and then recovering.

S6: adding the leached residue and water into a magnetic separation column for separation to obtain magnetic material and non-magnetic material.

The magnetic field strength of the magnetic separation column is 10000GS, and the water consumption is 60L/h.

S7: subjecting the magnetic material to a second acid leaching (normal pressure leaching) with sulfuric acid and hydrogen peroxide, and separating the solid from the liquid to obtain a second acid leaching solution.

In this step, the mass ratio of the magnetic material to sulfuric acid is 1:4, the concentration of sulfuric acid is 200 g/L, the amount of hydrogen peroxide used is 1.5 times the molar amount of the metal contained in the magnetic material, the pressure of the second acid leaching is 1 atmosphere, and the time of the second acid leaching is It is 180 minutes.

S8: extracting and removing impurities from the second acid leaching solution to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate.

The extraction in this step is carried out step by step with P507, P204 and C272.

S9: subjecting the non-magnetic material to a first acid leaching (pressure leaching) with sulfuric acid and hydrogen peroxide, and separating the solid from the liquid to obtain a first acid leaching residue and a first acid leaching liquid.

In this step, the mass ratio of the non-magnetic material to sulfuric acid is 1:3, the concentration of sulfuric acid is 200 g/L, the amount of hydrogen peroxide used is 1.2 times the molar amount of the metal contained in the non-magnetic material, the pressure of the first acid leaching is 1 MPa, and the time of the first acid leaching is 90 min.

S10: removing impurities and extracting the first acid leaching solution to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate.

This step is a stepwise extraction with P507, P204 and C272.

S11: The first acid leaching residue is subjected to a second roasting (low temperature oxygen roasting).

Air was introduced during the second roasting, the temperature of the second roasting was 450°C, and the time of the second roasting was 120 minutes.

S12: flotating the material obtained after the second calcination (second calcination product) through a flotation column to obtain a primary graphite product.

The flotation reagents used in this step include a collector, a frother and a regulator, wherein the collector is kerosene in an amount of 300 g/t, the frother is pine oil in an amount of 120 g/t, and the regulator is water glass in an amount of 1000 g/t.

S13: adding hydrochloric acid and nitric acid to purify the primary graphite product to obtain high-purity graphite.

Among them, the concentration of hydrochloric acid is 200g/L, the concentration of nitric acid is 200g/L, the mass ratio of the total amount of hydrochloric acid and nitric acid to the primary graphite product is 2:1, and the purification time is 100min.

S14: mixing high-purity graphite with asphalt so that the asphalt coats the high-purity graphite, and then carbonizing the graphite at high temperature to finally obtain a battery-grade graphite product.

The addition amount of asphalt is 6wt% of the high-purity graphite, and the high-temperature carbonization is carried out under oxygen-free conditions. The high-temperature carbonization temperature is 1200°C and the high-temperature carbonization time is 120 minutes.

The SEM image of the battery-grade graphite product obtained above is shown in FIG2 , from which it can be seen that the graphite is in the form of flakes and fragments, has very little impurities, and has a relatively smooth surface.

Example 2

The difference between this embodiment and embodiment 1 is that the temperature of the first calcination is 500°C.

Example 3

The difference between this embodiment and embodiment 1 is that the temperature of the second calcination is 300°C.

Example 4

The difference between this embodiment and embodiment 1 is that the temperature of the second calcination is 550°C.

Example 5

The difference between this embodiment and embodiment 1 is that the temperature of high-temperature carbonization is 1500°C.

Example 6

The difference between this embodiment and embodiment 1 is that the temperature of high-temperature carbonization is 800°C.

Example 7

This embodiment provides a method for processing waste ternary lithium batteries in an integrated manner, comprising the following steps:

S1: Discharge, crush, crack and screen the used nickel-cobalt-manganese ternary lithium batteries to obtain battery black powder.

S2: After the battery black powder and the coal powder are mixed evenly, a first roasting treatment is performed to obtain a first roasting product.

During the first calcination process, an inert gas (nitrogen) was passed to maintain an oxygen-free environment, the amount of coal powder added was 2wt% of the battery black powder, the temperature of the first calcination was 500°C, and the time of the first calcination was 240 minutes.

S3: placing the first calcined product into a container for water leaching of lithium, and performing solid-liquid separation to obtain a solid.

The mass ratio of the first roasted product to water is 1:5, and the time for water leaching lithium is 120 minutes.

S4: The solid obtained by leaching lithium with water is mixed with sulfuric acid to carry out acid leaching of lithium, and the solid-liquid separation is carried out to obtain leaching residue and leaching liquid.

The mass ratio of the solid matter extracted by sulfuric acid and water leaching used in the acid leaching process is 1:2, the concentration of sulfuric acid is 10g/L, and the time for acid leaching lithium is 100min.

S5: Sodium carbonate is introduced into the above leaching solution, heated and precipitated, and then recovered.

S6: adding the leached residue and water into a magnetic separation column for separation to obtain magnetic material and non-magnetic material.

The magnetic field strength of the magnetic separation column is 5000 GS, and the water consumption is 100 L/h.

S7: subjecting the magnetic material to a second acid leaching (normal pressure leaching) with sulfuric acid and sodium sulfite, and separating the solid from the liquid to obtain a second acid leaching solution.

In this step, the mass ratio of the magnetic material to sulfuric acid is 1:2, the concentration of sulfuric acid is 150 g/L, the amount of sodium sulfite used is 0.5 times the molar amount of the metal contained in the magnetic material, the pressure of the second acid leaching is 1 atmosphere, and the time of the second acid leaching is 240 min.

S8: extracting and removing impurities from the second acid leaching solution to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate.

This step is a stepwise extraction with P507, P204 and C272.

S9: subjecting the non-magnetic material to a first acid leaching (pressure leaching) with sulfuric acid and sodium sulfite, and separating the solid from the liquid to obtain a first acid leaching residue and a first acid leaching liquid.

In this step, the mass ratio of the non-magnetic material to sulfuric acid is 1:2, the concentration of sulfuric acid is 150 g/L, the amount of sodium sulfite used is 0.5 times the molar amount of the metal contained in the non-magnetic material, the pressure of the first acid leaching is 0.4 MPa, and the time of the first acid leaching is 120 min.

S10: removing impurities and extracting the first acid leaching solution to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate.

This step is a stepwise extraction with P507, P204 and C272.

S11: The first acid leaching residue is subjected to a second roasting (low temperature oxygen roasting).

Oxygen was introduced during the second roasting, the temperature of the second roasting was 300° C., and the time of the second roasting was 180 min.

S12: flotating the material obtained after the second calcination (second calcination product) through a flotation column to obtain a primary graphite product.

The flotation reagents used in this step include a collector, a frother and a regulator, wherein the collector is kerosene in an amount of 300 g/t, the frother is pine oil in an amount of 120 g/t, and the regulator is water glass in an amount of 1000 g/t.

S13: adding hydrochloric acid and nitric acid to purify the primary graphite product to obtain high-purity graphite.

Among them, the concentration of hydrochloric acid is 200g/L, the concentration of nitric acid is 200g/L, the mass ratio of the total amount of hydrochloric acid and nitric acid to the primary graphite product is 2:1, and the purification time is 100min.

S14: mixing high-purity graphite with asphalt so that the asphalt coats the high-purity graphite, and then carbonizing the graphite at high temperature to finally obtain a battery-grade graphite product.

The addition amount of asphalt is 2wt% of the high-purity graphite. The high-temperature carbonization is carried out under oxygen-free conditions. The temperature of the high-temperature carbonization is 800°C and the time of the high-temperature carbonization is 240 minutes.

Example 8

This embodiment provides a method for processing waste ternary lithium batteries in an integrated manner, comprising the following steps:

S1: Discharge, crush, crack and screen the used nickel-cobalt-manganese ternary lithium batteries to obtain battery black powder.

S2: After the battery black powder and the coal powder are mixed evenly, a first roasting treatment is performed to obtain a first roasting product.

During the first calcination process, an inert gas (argon) was passed to maintain an oxygen-free environment, the amount of coal powder added was 15wt% of the battery black powder, the temperature of the first calcination was 800°C, and the time of the first calcination was 30 minutes.

S3: placing the first calcined product into a container for water leaching of lithium, and performing solid-liquid separation to obtain a solid.

The mass ratio of the first roasted product to water is 1:14, and the time for water leaching lithium is 10 minutes.

S4: The solid obtained by leaching lithium with water is mixed with sulfuric acid to carry out acid leaching of lithium, and the solid-liquid separation is carried out to obtain leaching residue and leaching liquid.

The mass ratio of the solid matter extracted by sulfuric acid and water leaching used in the acid leaching process is 6:1, the sulfuric acid concentration is 100g/L, and the time for acid leaching lithium is 10min.

S5: introducing carbon dioxide into the above leaching solution, heating and precipitating, and then recovering.

S6: adding the leached residue and water into a magnetic separation column for separation to obtain magnetic material and non-magnetic material.

The magnetic field strength of the magnetic separation column is 12000GS, and the water consumption is 10L/h.

S7: The magnetic material is subjected to a second acid leaching (normal pressure leaching) with sulfuric acid and sodium thiosulfate, and the solid-liquid separation is performed to obtain the first Diacid leaching solution.

In this step, the mass ratio of the magnetic material to sulfuric acid is 1:5, the concentration of sulfuric acid is 400 g/L, the amount of sodium thiosulfate used is 3 times the molar amount of the metal contained in the magnetic material, the pressure of the second acid leaching is 1 atmosphere, and the time of the second acid leaching is 30 minutes.

S8: extracting and removing impurities from the second acid leaching solution to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate.

This step is a stepwise extraction with P507, P204 and C272.

S9: subjecting the non-magnetic material to a first acid leaching (pressure leaching) with sulfuric acid and sodium thiosulfate, and separating the solid from the liquid to obtain a first acid leaching residue and a first acid leaching liquid.

In this step, the mass ratio of the non-magnetic material to sulfuric acid is 1:5, the concentration of sulfuric acid is 400 g/L, the amount of sodium thiosulfate used is 3 times the molar amount of the metal contained in the non-magnetic material, the pressure of the first acid leaching is 1.5 MPa, and the time of the first acid leaching is 20 min.

S10: removing impurities and extracting the first acid leaching solution to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate.

This step is a stepwise extraction with P507, P204 and C272.

S11: The first acid leaching residue is subjected to a second roasting (low temperature oxygen roasting).

Air was introduced during the second roasting, the temperature of the second roasting was 550°C, and the time of the second roasting was 30 minutes.

S12: flotating the material obtained after the second calcination (second calcination product) through a flotation column to obtain a primary graphite product.

The flotation reagents used in this step include a collector, a frother and a regulator, wherein the collector is kerosene in an amount of 300 g/t, the frother is pine oil in an amount of 120 g/t, and the regulator is water glass in an amount of 1000 g/t.

S13: adding hydrochloric acid and nitric acid to purify the primary graphite product to obtain high-purity graphite.

Among them, the concentration of hydrochloric acid is 200g/L, the concentration of nitric acid is 200g/L, the mass ratio of the total amount of hydrochloric acid and nitric acid to the primary graphite product is 2:1, and the purification time is 100min.

S14: mixing high-purity graphite with asphalt so that the asphalt coats the high-purity graphite, and then carbonizing the graphite at high temperature to finally obtain a battery-grade graphite product.

The addition amount of asphalt is 15wt% of the high-purity graphite, and the high-temperature carbonization is carried out under oxygen-free conditions. The high-temperature carbonization temperature is 1500°C and the high-temperature carbonization time is 30 minutes.

Comparative Example 1

The difference between this comparative example and Example 1 is that in S1, no reducing agent is added to reduce the battery black powder, but the battery black powder is directly subjected to the first calcination treatment.

Comparative Example 2

The difference between this comparative example and Example 1 is that the lithium extraction method is a two-stage water immersion process, that is, the water immersion is repeated twice. Lithium is extracted (the process conditions for each water leaching of lithium are the same, all the same as S3 in Example 1), and acid leaching of lithium is not performed.

Comparative Example 3

The difference between this comparative example and Example 1 is that the leached residue obtained in S4 is not subjected to magnetic separation but directly subjected to the second acid leaching (normal pressure leaching). The process of graphite recovery in this comparative example is roughly as follows: first roasting - lithium extraction treatment - first acid leaching - second roasting - flotation - purification - graphite repair.

Comparative Example 4

The difference between this comparative example and Example 1 is that the first acid leaching residue obtained in S9 is not subjected to the second roasting (low-temperature aerobic roasting) but directly subjected to flotation. The process of graphite recovery in this comparative example is roughly as follows: first roasting - lithium extraction treatment - magnetic separation - first acid leaching - flotation - purification - graphite repair.

Comparative Example 5

The difference between this comparative example and Example 1 is that the second calcined product obtained in S11 is not subjected to flotation but directly purified. The process of graphite recovery in this comparative example is roughly as follows: first calcination - lithium extraction - magnetic separation - first acid leaching - second calcination - purification - graphite repair.

Comparative Example 6

The difference between this comparative example and Example 1 is that in S13, the graphite primary product is directly purified at a high temperature of 2600° C. without adding purification reagents such as hydrochloric acid and nitric acid.

Comparative Example 7

The difference between this comparative example and Example 1 is that a conventional flotation machine (XFD IV single-tank flotation machine produced by Jilin Prospecting Machinery Factory) is used for flotation instead of a flotation column.

Comparative Example 8

The difference between this comparative example and Example 1 is that the graphite primary product obtained in S11 is directly repaired without going through a purification process. The process of graphite recovery in this comparative example is roughly as follows: first roasting - lithium extraction - magnetic separation - first acid leaching - second roasting - flotation - graphite repair.

Test example

①. The recovery rates of Li, Ni, Co, Mn and C corresponding to the above Examples 1-8 and Comparative Examples 1-8 were tested, and the results are shown in Table 1.

Table 1 Example test results

It can be seen from Table 1 that the method provided by the embodiment of the present disclosure can achieve higher recovery rates of Li, Ni, Co, Mn and C at lower costs.

②. The battery-grade graphite product obtained in Example 1 was subjected to impurity content analysis, specific surface area measurement and electrochemical analysis. The results are shown in Table 2.

The test method of electrical performance is as follows: use metal lithium sheet as counter electrode, PZ12 as separator, 50μL of E30 as electrolyte, battery size is CR2430, battery structure is negative electrode shell - nickel foam - lithium sheet - electrolyte - separator - electrolyte - graphite electrode - positive electrode shell, assembled into a battery, at a current density of 10mA/g, use a blue electric test cabinet to perform constant current cycle test on button half-cells between 0.005V and 1.5V to evaluate its electrochemical performance.

Table 2 Example 1 Graphite Product Analysis

It can be seen from Table 2 that the graphite product recovered in Example 1 of the present disclosure can meet the needs of battery preparation, and can be further used to prepare batteries with good capacity and initial efficiency.

Industrial Applicability

The method for processing waste ternary lithium batteries in an integrated manner throughout the entire chain provided by the present invention is simple to operate, can realize full resource utilization of valuable components of battery black powder, and obtain higher recovery rates of Li, Ni, Co, Mn and C at lower costs.

Claims (25)

A method for processing waste ternary lithium batteries in an integrated manner, characterized by comprising the following steps: The battery black powder in the waste ternary lithium battery to be treated is first roasted with a reducing agent to obtain a first roasted product; the first roasted product is subjected to lithium extraction treatment, and the lithium extraction slag obtained by the lithium extraction treatment is subjected to magnetic separation; the non-magnetic material separated by magnetic separation is subjected to a first acid leaching, solid-liquid separation, and a first acid leaching slag is obtained; the first acid leaching slag is second roasted to obtain a second roasted product with amorphous carbon removed; and graphite in the second roasted product is floated. The method according to claim 1, characterized in that the reducing agent comprises at least one of coal powder, carbon powder and an organic carbon reducing agent; And/or, the mass ratio of the battery black powder to the reducing agent is 100:2-100:15. The method according to claim 1 or 2, characterized in that the first roasting includes at least one of the following features: Feature 1: The first roasting is carried out under oxygen-free conditions; Feature 2: The temperature of the first calcination is 500℃-800℃; Feature 3: The first roasting time is 30min-240min. The method according to any one of claims 1 to 3 is characterized in that the lithium extraction treatment comprises: first subjecting the first roasted product to water leaching for lithium, and then subjecting the solid obtained by the water leaching for lithium to acid leaching. The method according to claim 4, characterized in that, during the water leaching of lithium, the mass ratio of the first calcined product to water is 1:3-1:15; and/or the time for water leaching of lithium is 10 min-120 min. The method according to claim 4, characterized in that the acid leaching process for lithium includes at least one of the following characteristics: Feature 1: The acid used for acid leaching of lithium includes sulfuric acid; Feature 2: The concentration of the acid used in the acid leaching process is 10g/L-100g/L, and the mass ratio of the acid used in the acid leaching process to the solid matter extracted by water leaching is 2:1-6:1; Feature 3: The time for acid leaching of lithium is 10min-100min. The method according to any one of claims 1 to 6, characterized in that the magnetic separation comprises at least one of the following features: Feature 1: Magnetic separation is carried out in a magnetic separation column; Feature 2: The magnetic field strength used for magnetic separation is 2000GS-12000GS; Feature 3: Magnetic separation is carried out in the presence of water, with a water volume of 10L/h-100L/h. The method according to any one of claims 1 to 7, characterized in that the first acid leaching comprises: pressurizing the non-magnetic material with a first acid and a first oxidant for leaching. The method according to claim 8, characterized in that the first pickling process includes at least one of the following features: Feature 1: the first acid includes sulfuric acid; Feature 2: The mass ratio of the non-magnetic material to the first acid is 1:2-1:5, and the concentration of the first acid is 150g/L-400g/L; Feature 3: The amount of the first oxidant is 0.5 to 3 times the molar amount of the metal contained in the non-magnetic material; Feature 4: The first oxidant includes at least one of hydrogen peroxide, sodium sulfite and sodium thiosulfate; Feature 5: The pressure of the first acid leaching is 0.4MPa-1.5MPa; Feature 6: The first acid leaching time is 20min-120min. The method according to any one of claims 1 to 7, characterized in that the second roasting includes at least one of the following features: Feature 1: The second roasting is carried out under oxygen conditions; Feature 2: The temperature of the second calcination is 300℃-550℃; Feature 3: The second roasting time is 30min-180min. The method according to any one of claims 1 to 10, characterized in that flotation is carried out in a flotation column. The method according to any one of claims 1 to 11 is characterized in that the floated graphite is repaired to obtain battery-grade graphite. The method according to claim 12 is characterized in that the repair process includes: coating the graphite with a carbon-containing substance and then carbonizing it at high temperature. The method according to claim 13, characterized in that the carbon-containing material includes at least one of asphalt, glucose and sucrose. The method according to claim 13 or 14, characterized in that the amount of the carbon-containing substance is 2wt%-15wt% of the graphite. The method according to any one of claims 13 to 15 is characterized in that the high temperature carbonization temperature is 800° C. to 1500° C., and/or the high temperature carbonization time is 30 min to 240 min; and/or the high temperature carbonization is carried out in an oxygen-free atmosphere. The method according to any one of claims 12 to 16 is characterized in that, before repairing, it also includes purifying the graphite. The method according to claim 17, characterized in that the reagents used for purification include hydrochloric acid and nitric acid. The method according to any one of claims 1 to 18 is characterized in that the lithium extraction liquid obtained by the lithium extraction process is subjected to lithium precipitation treatment to obtain a lithium-containing product. The method according to any one of claims 1 to 19 is characterized in that the magnetic material obtained by magnetic separation is subjected to a second acid leaching, solid-liquid separation, to obtain a second acid leaching solution; the second acid leaching solution is extracted and impurities are removed to obtain a first product containing nickel sulfate, cobalt sulfate and manganese sulfate. The method according to claim 20 is characterized in that the second acid leaching comprises: leaching the magnetic material with a second acid and a second oxidant at normal pressure. The method of claim 21, wherein the second pickling process comprises at least one of the following features: Feature 1: the second acid includes sulfuric acid; Feature 2: The mass ratio of the magnetic material to the second acid is 1:2-1:5, and the concentration of the second acid is 150g/L-400g/L; Feature 3: The amount of the second oxidant is 0.5 to 3 times the molar amount of the metal contained in the magnetic material; Feature 4: The second oxidant includes at least one of hydrogen peroxide, sodium sulfite and sodium thiosulfate; Feature 5: The second acid leaching time is 30min-240min. The method according to any one of claims 20 to 22, characterized in that the extraction reagent used when the second acid leaching solution is extracted includes at least one of 2-ethylhexyl mono-2-ethylhexyl phosphate, di(2-ethylhexyl) phosphate and di(2,4,4-trimethylpentyl)phosphinic acid. The method according to any one of claims 1 to 23, characterized in that the first acid leaching liquid obtained after the first acid leaching is subjected to impurity removal and extraction to obtain a second product containing nickel sulfate, cobalt sulfate and manganese sulfate. The method according to claim 24, characterized in that the extraction reagent used when the first acid leaching solution is extracted includes at least one of 2-ethylhexyl mono-2-ethylhexyl phosphate, di(2-ethylhexyl) phosphate and di(2,4,4-trimethylpentyl)phosphinic acid.