Method for recovering valuable metals

Abstract

The present invention provides a method for recovering valuable metals, the method comprising the steps of: (S1) dry-heat-treating a crushed LFP waste battery to obtain a high-temperature reduction reaction product; (S2) subjecting the high-temperature reduction reaction product to first pulverization, followed by first magnetic separation to obtain a first magnetic material and a first non-magnetic material; and (S3) post-treating at least one of the first magnetic material and the first non-magnetic material, wherein step (S3) includes at least one of the following steps (S3-1) and (S3-2). In step (S3-1), the first magnetic material is subjected to second pulverization, followed by second magnetic separation to obtain a second magnetic material and a second non-magnetic material, and in step (S3-2), the first non-magnetic material is subjected to ultrasonic treatment, followed by flotation to obtain a floated fraction and a settled fraction.

Description

Method for recovering valuable metals

[0001] The present invention relates to waste battery recycling, and more specifically, to a method for recovering valuable metals from waste LFP batteries.

[0002] The present invention claims priority based on Korean Patent Application No. 10-2024-0191906 filed on December 19, 2024, the entire contents of said application incorporated herein by reference.

[0003] The issue of disposing of secondary batteries, such as spent electric vehicle batteries, is emerging globally. In particular, as EV batteries are recently shifting from NCM-based secondary batteries to the more affordable LFP-based secondary batteries, there is a growing trend of demand for these batteries in entry-level electric vehicles.

[0004] Conventional recycling methods for spent LFP batteries utilize an upstream process for producing black mass through processes such as discharge, crushing, heat treatment, and iron removal—similar to existing spent NCM batteries—and a downstream process for wet smelting the black mass to recover Li compounds and Fe compounds. However, because the economic value of the recovered materials other than Li compounds is very low, the recycling of spent LFP batteries using these methods is currently insufficient.

[0005] The objective of the present invention is to provide an economical and high-yield method for recovering valuable metals, in addition to Li compounds, from spent LFP batteries to solve the aforementioned problems.

[0006] One embodiment of the present invention provides a method for recovering valuable metals, comprising: (S1) a step of obtaining a high-temperature reduction reaction product by dry heat treatment of crushed LFP waste batteries; (S2) a step of obtaining a first magnetic material and a first non-magnetic material by first crushing the high-temperature reduction reaction product and then first magnetic separation; and (S3) a step of post-processing at least one of the first magnetic material and the first non-magnetic material; wherein step (S3) comprises at least one of the following steps (S3-1) and (S3-2).

[0007] (S3-1) Step; secondarily crush the first magnetic material and then perform secondary magnetic separation to obtain a second magnetic material and a second non-magnetic material.

[0008] (S3-2) Step; obtaining suspended matter and suspended sediment by flotation separation after ultrasonic treatment of the first non-magnetic material.

[0009] In the above step (S2), the first grinding is carried out by a rod mill, and the first grinding can grind the high-temperature reduction reaction product to 1 mm or less.

[0010] In the above step (S2), between the first grinding and the first magnetic separation, a step of repeating the first grinding for the ground material with a particle size of 1 mm or more by separating the particle size through screening may be included.

[0011] In the above step (S2), the primary magnetic separation is carried out under wet conditions, and the solid-liquid ratio under wet conditions may be 5 to 40 wt.

[0012] In the above step (S2), the first magnetic separation can be repeated 1 to 10 times.

[0013] In the above step (S3-1), the secondary grinding is carried out under wet conditions, and under wet conditions, the solid-liquid ratio may be 5 to 50 wt%.

[0014] The above secondary grinding can be carried out by a vertical stirring mill.

[0015] The above secondary grinding can be carried out for 10 to 120 minutes.

[0016] In the above step (S3-2), the ultrasonic treatment is performed under wet conditions, and the solid-liquid ratio under wet conditions may be 5 to 40 wt%.

[0017] In the above step (S3-2), the ultrasonic treatment can be carried out at 10 to 70 kW / L for 10 to 60 minutes.

[0018] The above step (S3-2) may include a step of introducing an oxidizing agent between the ultrasonic treatment and the floating separation.

[0019] In the above step (S3-2), the flotation separation is carried out by introducing a hydrocarbon oil and a foaming agent, and the hydrocarbon oil and the foaming agent can be introduced independently in amounts of 10 to 400 g / ton.

[0020] The above step (S3-2) includes a step of separating the suspended sediment by specific gravity to obtain high-specific gravity and low-specific gravity materials, and the specific gravity separation may be carried out by a hydrocyclone or screening.

[0021] At least one of the above first magnetic separation and the above second magnetic separation can be carried out at a magnetic force of 1,000 gauss or more.

[0022] After the above step (S3-1) or the above step (S3-2), a step of solid-liquid separation and drying may be included.

[0023] In the above step (S1), the dry heat treatment can be carried out in a temperature range of 800 to 1,300°C.

[0024] In the above (S3-1) step, the Fe recovered as the second magnetic material may be 70% or more of the total recovered Fe.

[0025] In the above step (S3-1), the amount of P recovered as the second magnetic material and the second non-magnetic material may be 75% or more of the total recovered P.

[0026] In step (S3-2) above, the graphite recovered as the floating material and the floating sediment may be 85% or more of the total recovered graphite.

[0027] In step (S3-2) above, the Cu recovered as the floating precipitate may be 80% or more of the total recovered Cu.

[0028] In the above step (S3-1), the average particle size (D50) of the second magnetic material may be 7 to 12 μm.

[0029] In the above step (S3-1), the average particle size (D50) of the second non-magnetic material may be 2 to 8 μm.

[0030] A method for recovering valuable metals according to one embodiment of the present invention is environmentally friendly as it does not involve an acid leaching process, is economical as it can recover Li, Fe, and P in the form of useful alloys, and can recover compounds mixed with graphite and Cu, etc., in addition to the aforementioned alloys with high purity.

[0031] FIG. 1 is a flowchart of a method for recovering valuable metals according to one embodiment of the present invention.

[0032] FIGS. 2a to 2d are scanning electron microscope (SEM) images and component analysis results of an LFP waste battery, a crushed material, a high-temperature reduction reactant, and a high-temperature reduction reactant according to one embodiment of the present invention.

[0033] FIGS. 3a and 3b are X-ray diffraction (XRD) graphs of a first magnetic material and a first non-magnetic material according to an embodiment of the present invention.

[0034] FIGS. 4a and 4b are X-ray diffraction (XRD) graphs of a second magnetic material and a second non-magnetic material according to one embodiment of the present invention.

[0035] FIGS. 5a to 5c are particle size distribution (PSD) graphs of a first non-magnetic material, a second magnetic material, and a second non-magnetic material according to an embodiment of the present invention.

[0036] FIGS. 6a to 6c are photographs of a floating material, a second magnetic material, and a second non-magnetic material according to one embodiment of the present invention.

[0037] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0038] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0039] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between.

[0040] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0041]

[0042]

[0043] Method for recovering valuable metals

[0044] In one embodiment of the present invention, a method for recovering valuable metals is provided that is environmentally friendly as there is no acid leaching process, is economical as Li, Fe, and P can be recovered in the form of a useful alloy, and recovers a compound mixed with graphite and Cu, etc., in addition to the aforementioned alloy, with high purity.

[0045] FIG. 1 is a flowchart of a method for recovering valuable metals according to one embodiment of the present invention.

[0046] Referring to FIG. 1, in one embodiment, a method for recovering valuable metals comprises: (S1) a step of obtaining a high-temperature reduction reaction product by dry heat treatment of crushed LFP waste batteries; (S2) a step of obtaining a first magnetic material and a first non-magnetic material by first crushing the high-temperature reduction reaction product and then performing first magnetic separation; and (S3) a step of post-processing at least one of the first magnetic material and the first non-magnetic material; wherein step (S3) may include at least one of the following steps (S3-1) and (S3-2), wherein step (S3-1) is a step of obtaining a second magnetic material and a second non-magnetic material by seconding the first magnetic material and then performing second magnetic separation, and step (S3-2) is a step of obtaining a floating material and a floating precipitate by ultrasonically treating the first non-magnetic material and then performing flotation separation.

[0047] In step (S1) above, the LFP waste battery shredded material is LFP waste battery shredded, and the LFP waste battery may include waste materials from the manufacturing process of lithium-ion batteries, such as LFP secondary batteries that have reached the end of their lifespan, positive electrode materials such as scrap, jelly rolls, and slurries constituting the waste battery, defective products generated during the manufacturing process, residues within the manufacturing process, and generated debris. The shredded material itself may be the shredded product itself, such as black powder.

[0048] In one embodiment, the method for recovering valuable metals may perform dry heat treatment in step (S1) at a temperature range of 800 to 1,300°C. Specifically, the temperature range may be 900 to 1,200°C, 1,100 to 1,200°C, or 1,000 to 1,200°C. The dry heat treatment may be performed by heating to a temperature above the melting point of the crushed LFP waste battery. Additionally, the process may proceed to a high-temperature reduction reaction without undergoing a melting step, and may be performed under an inert atmosphere.

[0049] In one embodiment, the method for recovering valuable metals may perform the primary crushing in step (S2) by a rod mill, and the primary crushing may crush the high-temperature reduction reactant to a size of 1 mm or less. This is to crush coarse particles in the high-temperature reduction reactant to separate them into magnetic and non-magnetic materials. In one embodiment, the method for recovering valuable metals may include a step between the primary crushing and the primary magnetic separation in step (S2) of repeating the primary crushing on crushed materials of 1 mm or more by separating particle sizes through screening.

[0050] In one embodiment, the method for recovering valuable metals may proceed with the primary magnetic separation in step (S2) under wet conditions, and the solid-liquid ratio under wet conditions may be 5 to 40 wt%. Specifically, the solid-liquid ratio may be 5 to 35 wt%, 5 to 30 wt%, 10 to 40 wt%, or 10 to 30 wt%. At this time, the solid-liquid ratio may be satisfied by mixing the primary crushed material, which is 1 mm or less, with water. In one embodiment, the method for recovering valuable metals may repeat the primary magnetic separation in step (S2) 1 to 10 times. Specifically, it may be repeated 1 to 8 times or 1 to 5 times. At this time, the first magnetic material may be an alloy comprising Li, Fe, P, Al, or a combination thereof, and the first non-magnetic material may include a Li compound, Al oxide, Cu, graphite, or a combination thereof.

[0051] In one embodiment, in the method for recovering valuable metals, the secondary crushing in step (S3-1) is carried out under wet conditions, and the solid-liquid ratio under wet conditions may be 5 to 50 wt%. Additionally, the secondary crushing may be carried out by a vertical stirring mill and may be carried out for 10 to 120 minutes. The rpm of the mill may be 200 to 1,000 rpm. At this time, the vertical stirring mill can separate the first magnetic material into individual independent particles by shear force. Through this, the first magnetic material can be separated into independent particles of an alloy containing Fe and P and an alloy containing Li and P.

[0052] In one embodiment, in step (S3-1), the average particle size (D50) of the second magnetic material may be 7 to 12 μm, specifically 8 to 11 μm, and the average particle size (D50) of the second non-magnetic material may be 2 to 8 μm, specifically 4 to 6 μm. At this time, the Li compound, Al oxide, Cu, graphite, or a combination thereof that was included in the first magnetic material may mostly be separated into the second non-magnetic material.

[0053] In one embodiment, the method for recovering valuable metals in step (S3-2) is such that the ultrasonic treatment is performed under wet conditions, and the solid-liquid ratio under wet conditions may be 5 to 40 wt%. Additionally, in one embodiment, the ultrasonic treatment may be performed at 10 to 70 kW / L for 10 to 60 minutes. Specifically, the solid-liquid ratio may be 5 to 35 wt%, 5 to 30 wt%, 10 to 40 wt%, or 10 to 30 wt%, and the solid-liquid ratio may be satisfied by mixing with water. Additionally, the ultrasonic treatment may be performed specifically at 20 to 50 kW / L or 30 to 60 kW / L for 20 to 50 minutes or 20 to 40 minutes.

[0054] In one embodiment, the method for recovering valuable metals may include a step of introducing an oxidizing agent between the ultrasonic treatment and the flotation separation in step (S3-2). The oxidizing agent is intended to aid in flotation separation and, specifically, may be hydrogen peroxide or triethanolamine, but is not limited thereto and can be modified by the common sense of a person skilled in the art without compromising the purpose of the present invention.

[0055] In one embodiment, in the method for recovering valuable metals, the flotation separation in step (S3-2) is carried out by introducing a hydrocarbon oil and a foaming agent, and the hydrocarbon oil and the foaming agent may be introduced independently in amounts of 10 to 400 g / ton. Specifically, the amounts may be 10 to 300 g / ton, 50 to 400 g / ton, 100 to 400 g / ton, or 100 to 300 g / ton. Furthermore, the hydrocarbon oil may specifically be kerosene, and the foaming agent may specifically be MIBC (methyl isobutyl carbinol), but is not limited thereto and can be modified by the common sense of a person skilled in the art without compromising the purpose of the present invention. At this time, the floating material may include graphite, and the floating precipitate may include Cu, Li compounds, or a combination thereof.

[0056] In one embodiment, the method for recovering valuable metals includes the step of obtaining high-density and low-density materials by separating the suspended precipitate by specific gravity in step (S3-2), and the specific gravity separation may be carried out by a hydrocyclone or screening. At this time, the suspended precipitate may be separated such that Cu, which has a large particle size and specific gravity, becomes high-density material, and Li compounds, which do not, become low-density material.

[0057] In one embodiment, the method for recovering valuable metals may perform at least one of the primary magnetic separation and the secondary magnetic separation at a magnetic force of 1,000 gauss or more.

[0058] In one embodiment, the method for recovering valuable metals may include a step of solid-liquid separation and drying after step (S3-1) or step (S3-2). This is a step for finally obtaining the second magnetic material, the second non-magnetic material, the floating material, the floating precipitate, the high-density material, the low-density material, or a combination thereof.

[0059] In one embodiment, the method for recovering valuable metals may have Fe recovered as the second magnetic material in step (S3-1) as 70% or more of the total recovered Fe, specifically 72% or more, 74% or more, or 76% or more. In this case, the total recovered Fe refers to the wt% of Fe contained in the second magnetic material when the Fe contained in the total product is set to 100 wt%, i.e., it may refer to the recovery rate of Fe contained in the crushed LFP waste battery. In this case, the total product refers to the entirety of the second magnetic material, the second non-magnetic material, the floating material, and the floating sediment.

[0060] In one embodiment, the method for recovering valuable metals may have P recovered in the second magnetic material and the second non-magnetic material in step (S3-1) as 75% or more of the total recovered P, specifically 78% or more, 80% or more, or 82% or more. At this time, the total recovered P refers to the wt% of P contained in the second magnetic material and the second non-magnetic material when the P contained in the total product is set to 100 wt%, that is, it may refer to the recovery rate of P contained in the LFP waste battery shreds.

[0061] In one embodiment, the method for recovering valuable metals may have at least 85%, specifically 87% or 89%, of the total recovered graphite in the floating material and the floating sediment in step (S3-2). In this case, the total recovered graphite refers to the wt% of graphite contained in the floating material and the floating sediment when the graphite contained in the total product is set to 100 wt%, i.e., it may refer to the recovery rate of graphite contained in the crushed LFP waste battery. Additionally, this may mean that the second magnetic material and the second non-magnetic material, which are alloys containing Li, Fe, P, or combinations thereof—that is, materials mainly containing valuable metals—contain 15% or less of graphite. In other words, it means that there is little graphite, which is an impurity, when recovering the valuable metals.

[0062] In one embodiment, the method for recovering valuable metals may have at least 80%, specifically 82%, or 84% of the total recovered Cu recovered as the floating precipitate in step (S3-2). At this time, the total recovered Cu refers to the wt% of Cu contained in the floating precipitate when the Cu contained in the total product is set to 100 wt%, i.e., it may refer to the recovery rate of Cu contained in the crushed waste LFP battery. This means that Cu can be recovered in a high grade in addition to alloys containing Li, Fe, P, or combinations thereof.

[0063]

[0064] Preferred embodiments and comparative examples of the present invention are described below. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0065]

[0066] Examples

[0067] (S1) Step; dry heat-treat crushed LFP waste batteries to obtain a high-temperature reduction product.

[0068] After discharging one spent LFP battery cell, it was crushed without a separate separation process, and then a high-temperature reduction reaction was carried out at 1,100°C for 1 hour in an Ar atmosphere to obtain a high-temperature reduction reaction product.

[0069] FIGS. 2a to 2d are scanning electron microscope (SEM) images and component analysis results of an LFP waste battery, a crushed material, a high-temperature reduction reactant, and a high-temperature reduction reactant according to one embodiment of the present invention.

[0070] Looking at FIGS. 2a to 2c, it can be seen that the process involves discharging and disassembling a waste LFP battery, crushing the waste LFP battery to obtain a crushed waste LFP battery, and then heat-treating the crushed waste LFP battery to obtain a high-temperature reduction reaction product. Additionally, looking at FIG. 2d, the high-brightness areas of the high-temperature reduction reaction product can be inferred to be an Fe2P alloy because they have significantly high Fe and P content, while the low-brightness, dark areas within the high-temperature reduction reaction product can be inferred to be a non-magnetic material containing Li3PO4 because they have low Fe content and high P content.

[0071]

[0072] (S2) Step; primary grinding of the high-temperature reduction reaction product followed by primary magnetic separation to obtain a first magnetic material and a first non-magnetic material.

[0073] The high-temperature reduction reaction product was ground to a size of 1 mm or less using a rod mill capable of selective crushing. At this time, the ground material larger than 1 mm was fed back into the rod mill through screening and the grinding process was repeated until it became 1 mm or less. Subsequently, the ground material smaller than 1 mm was mixed with water to achieve a solid-liquid ratio of 30 wt%, and primary magnetic separation was performed using a magnetic force of 1,000 gauss or more to obtain a first magnetic material and a first non-magnetic material.

[0074]

[0075] (S3-1) Step; secondarily crush the first magnetic material and then perform secondary magnetic separation to obtain the second magnetic material and the second non-magnetic material.

[0076] The first magnetic material was ground in a slurry state with water and a solid-liquid ratio of 30 wt% using a vertical stirring mill at 500 rpm for 30 minutes, and then secondary magnetic separation was performed with a magnetic force of 1,000 gauss or more to obtain the second magnetic material and the second non-magnetic material. Subsequently, the second magnetic material and the second non-magnetic material were finally obtained through solid-liquid separation and drying.

[0077]

[0078] (S3-2) Step; obtain suspended matter and suspended sediment by ultrasonically treating the first non-magnetic material and then separating it from the flotation.

[0079] The first nonmagnetic material was ultrasonically treated for 30 minutes at an intensity of 20 kW per liter in a slurry state with a solid-liquid ratio of 15 wt% with water, and then 100 g / ton of kerosene and 150 g / ton of MIBC (methyl isobutyl carbinol) were added to perform flotation separation to obtain suspended solids and suspended precipitates. Subsequently, the suspended solids and suspended precipitates were finally obtained through solid-liquid separation and drying.

[0080] FIGS. 6a to 6c are photographs of a floating material, a second magnetic material, and a second non-magnetic material according to one embodiment of the present invention.

[0081] Looking at Figures 6a to 6c, it can be seen at a glance that the color of each material is different. Through this, it can be seen that the floating material, the second magnetic material, and the second non-magnetic material each have different materials as their main materials.

[0082]

[0083] Evaluation example

[0084] (1) XRD analysis

[0085] FIGS. 3a and 3b are X-ray diffraction (XRD) graphs of a first magnetic material and a first non-magnetic material according to an embodiment of the present invention.

[0086] FIGS. 4a and 4b are X-ray diffraction (XRD) graphs of a second magnetic material and a second non-magnetic material according to one embodiment of the present invention.

[0087] XRD analysis was performed on the first magnetic material, first non-magnetic material, second magnetic material, and second non-magnetic material obtained at each step of the above example, and is shown in FIGS. 3a, 3b, 4a, and 4b. At this time, XRD analysis was performed on the powder obtained after drying at 105°C for 24 hours.

[0088] As shown in Fig. 3a, it can be seen that the first magnetic material contains a mixture of Fe2P, Al2O3, Li3PO4, and SiO2, and as shown in Fig. 3b, it can be seen that the first non-magnetic material contains a mixture of graphite, LiAlO2, and Al2O3. In other words, it can be seen that Fe2P and Li3PO4, which are P-containing alloys, can be separated and recovered as the first magnetic material through primary crushing and primary magnetic separation.

[0089] Looking at Fig. 4a, it can be seen that the second magnetic material contains graphite, Fe2P, and Al2O3, and that graphite and Fe2P are the main materials and Al2O3 is an impurity. Also, looking at Fig. 4b, it can be seen that the second non-magnetic material contains Li3PO4, Al2O3, and SiO2, and that Li3PO4 is the main material and Al2O3 and SiO2 are impurities.

[0090] That is, through secondary crushing, the alloy containing Fe and P and the non-magnetic material containing Li and P as described in FIG. 2d above were effectively separated, and it can be seen that they can be finally separated and obtained through secondary magnetic separation. In addition, since Fe2P and Li3PO4 are the main materials in the second magnetic material and the second non-magnetic material, respectively, it can be seen that the method for recovering valuable metals according to the embodiment of the present invention can effectively separate and recover valuable metals containing Li, Fe, P, or a combination thereof.

[0091]

[0092] (2) PSD Analysis

[0093] FIGS. 5a to 5c are particle size distribution (PSD) graphs of a first non-magnetic material, a second magnetic material, and a second non-magnetic material according to an embodiment of the present invention.

[0094] PSD analysis was performed on the first non-magnetic material, the second magnetic material, and the second non-magnetic material obtained at each step of the above example, as shown in FIGS. 5a to 5c. At this time, the PSD analysis was performed under aqueous solution conditions using a Malvern Master Size 3000 laser scattering particle size analyzer.

[0095] Looking at Fig. 5a, it can be seen that the first non-magnetic material consists of two peaks, that is, materials with two types of particle sizes. At this time, the average particle size (D50) is 18.4 μm and D90 is 288 μm, and when considering Fig. 3b mentioned above together, it can be inferred that the material with the larger particle size is an alloy of Fe2P, Al2O3, and Cu. In other words, it can be seen that the first non-magnetic material contains alloys of Fe2P, Al2O3, and Cu with coarse particle sizes as impurities.

[0096] Looking at Fig. 5b, it can be seen that the second magnetic material is also composed of two peaks, that is, two types of particle sizes. At this time, the average particle size (D50) is 9.88 μm and D90 is 479 μm, and when considering Fig. 4a mentioned above together, the material with the larger particle size can be presumed to be Cu, etc. In other words, it can be seen that the second magnetic material contains Cu with a coarse particle size as an impurity.

[0097] Looking at Fig. 5c, it can be seen that the second magnetic material consists of a material with almost a single peak, that is, a single type of particle size. At this time, the average particle size (D50) is 5.2 μm and D90 is 44.3 μm, and when considering Fig. 4b mentioned above together, it can be inferred that the material with the large particle size is Fe2P and Al2O3. In other words, it can be seen that the second non-magnetic material contains an alloy with a coarse particle size as an impurity.

[0098]

[0099] (3) Sorting Results - Quality Analysis by Product

[0100] The composition of the second magnetic material, second non-magnetic material, suspended material, and suspended precipitate finally obtained in the above examples was analyzed for the grades of Li, Fe, P, Al, Cu, and graphite, and is shown in Tables 1 and 2 below.

[0101] In this case, Table 1 below shows the mass of the corresponding element recovered for each product, with all units in g, and Table 2 below shows the ratio of the corresponding element recovered for each product, calculated by determining the wt% of the element for each product based on 100 wt% of the total mass of each element in the total products. Through this, one can intuitively verify how much of the corresponding element was recovered from each product.

[0102] Total Mass LiFe PAlCuC Secondary Magnetic Material 165.38 2.49 28.43 6.07 13.97 12.25 82.49 Secondary Non-magnetic Material 119.8 2.6 120.1 220.48 1.35 2.78 2.61 Suspended Material 63.31 1.67 0.1 22.6 31.06 56.6 11.67 Suspended Sediment 293.31 7.9 29.71 16.8 197.98 67.94 17.92

[0103] Li (wt%) Fe (wt%) P (wt%) Al (wt%) Cu (wt%) C (wt%) Secondary Magnetic 8.87 78.79 48.71 3.19 12.22 8.78 Secondary Non-magnetic 55.0 12.49 34.47 44.54 1.18 1.99 Suspended 0.8 1.59 0.215.71 0.92 40.56 Suspended Sediment 35.32 17.12 16.63 36.55 85.68 48.67

[0104] Looking at Table 1 and Table 2 above, it can be confirmed that the second magnetic material is composed of Fe2P alloys with Fe and P as the main materials, and that more than 78% of Fe and more than 48% of P were recovered from the total yield. In addition, although it contains Li, Al, Cu, and graphite as impurities, these amount to only 33.91 g out of the total mass of 165.31 g of the second magnetic material, which is about 20 wt%, so it can be considered that the second magnetic material was recovered as a high-quality Fe2P alloy.

[0105] The second non-magnetic material contains 20.48 g of Al as an impurity, amounting to approximately 17 wt% of the total mass of 119.79 g, but it can be seen that more than 55% of Li and more than 16% of P were recovered from the total product. In other words, the second non-magnetic material contains Li and P in the form of a Li3PO4 alloy, and it can be considered that Li was effectively recovered through the second non-magnetic material. It can be confirmed that the float contains 56.61 g of graphite, amounting to approximately 89 wt% of the total mass of 63.31 g, indicating that graphite can be recovered in a high grade.

[0106] It can be seen that the main component of the suspended precipitate is Cu, and that more than 85% of the total yield was recovered as Cu. Additionally, since the total yield contains about 35% Li, it can be considered that some Li compounds were recovered as suspended precipitates. However, as previously mentioned, Cu and Li compounds can be obtained as high-density compounds with large particle sizes and low-density compounds with relatively small particle sizes through specific gravity separation such as hydrocyclone or screening. Therefore, since valuable metals such as Li, Fe, P, Cu, and Al can be obtained in the form of alloys with a high recovery rate without an acid leaching process through the present invention, it can be seen that valuable metals can be recovered in an environmentally friendly and economical manner through the present invention.

[0107] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. (S1) A step of obtaining a high-temperature reduction reaction product by dry heat treating crushed LFP waste batteries; (S2) A step of obtaining a first magnetic material and a first non-magnetic material by first grinding the high-temperature reduction reaction product and then first magnetic separation; and (S3) A step of post-processing at least one of the first magnetic material and the first non-magnetic material; comprising, The above step (S3) includes at least one of the following steps (S3-1) and (S3-2), Method for recovering valuable metals. (S3-1) Step; secondarily crush the first magnetic material and then perform secondary magnetic separation to obtain a second magnetic material and a second non-magnetic material. (S3-2) Step; obtaining suspended matter and suspended sediment by flotation separation after ultrasonic treatment of the first non-magnetic material.

2. In Paragraph 1, In the above step (S2), the primary grinding is carried out by a rod mill, and The above first grinding grinds the above high-temperature reduction reactant to 1 mm or less, Method for recovering valuable metals.

3. In Paragraph 2, In the above (S2) step, between the first crushing and the first magnetic separation, A method comprising the step of repeating primary grinding for crushed materials larger than 1 mm by separating particle sizes through screening, Method for recovering valuable metals.

4. In Paragraph 1, In the above step (S2), the first magnetic separation is performed under wet conditions, and Under the above wet conditions, the solid-to-liquid ratio is 5 to 40 wt%, Method for recovering valuable metals.

5. In Paragraph 1, In the above step (S2), the first magnetic separation is repeated 1 to 10 times. Method for recovering valuable metals.

6. In Paragraph 1, In the above step (S3-1), the secondary grinding is carried out under wet conditions, and Under the above wet conditions, the solid-to-liquid ratio is 5 to 50 wt%, Method for recovering valuable metals.

7. In Paragraph 6, The above secondary grinding is carried out by a vertical stirring mill, Method for recovering valuable metals.

8. In Paragraph 1, In the above step (S3-2), the ultrasonic treatment is performed under wet conditions, and Under the above wet conditions, the solid-to-liquid ratio is 5 to 40 wt%, Method for recovering valuable metals.

9. In Paragraph 1, In the above step (S3-2), the ultrasonic treatment is performed at 10 to 70 kW / L for 10 to 60 minutes, Method for recovering valuable metals.

10. In Paragraph 1, The step of introducing an oxidizing agent between the ultrasonic treatment and the flotation separation in the above (S3-2) step, Method for recovering valuable metals.

11. In Paragraph 1, In the above (S3-2) step, the flotation separation is carried out by introducing hydrocarbon oil and a foaming agent, and The above hydrocarbon oil and the above foaming agent are independently introduced in amounts of 10 to 400 g / ton, Method for recovering valuable metals.

12. In Paragraph 1, The above (S3-2) step includes the step of separating the suspended precipitate by specific gravity to obtain high-specific gravity and low-specific gravity materials, and The above specific gravity separation is carried out by a hydrocyclone or screening, Method for recovering valuable metals.

13. In Paragraph 1, A step of solid-liquid separation and drying after the above (S3-1) step or the above (S3-2) step, Method for recovering valuable metals.

14. In Paragraph 1, In the above step (S1), the dry heat treatment is performed in a temperature range of 800 to 1,300℃, Method for recovering valuable metals.

15. In Paragraph 1, In the above step (S3-1), the Fe recovered as the second magnetic material is 70% or more of the total recovered Fe, Method for recovering valuable metals.

16. In Paragraph 1, In the above step (S3-1), the P recovered as the second magnetic material and the second non-magnetic material is 75% or more of the total recovered P, Method for recovering valuable metals.

17. In Paragraph 1, In the above step (S3-2), the graphite recovered as the floating matter and the floating sediment is 85% or more of the total recovered graphite, Method for recovering valuable metals.

18. In Paragraph 1, In the above step (S3-2), the Cu recovered as the suspended precipitate is 80% or more of the total recovered Cu, Method for recovering valuable metals.

19. In Paragraph 1, In the above step (S3-1), the average particle size (D50) of the second magnetic material is 7 to 12 μm, Method for recovering valuable metals.

20. In Paragraph 1, In the above step (S3-1), the average particle size (D50) of the second non-magnetic material is 2 to 8 μm, Method for recovering valuable metals.

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