Method for recovering valuable metals from electronic waste

Abstract

The application discloses a method for recycling valuable metals in electronic waste, and relates to the technical field of lithium ion batteries, and the method comprises the following steps: mixing electronic waste powder, boron nitride, a grinding aid and a first solvent in a certain proportion, applying mechanical stress to perform grinding treatment, and obtaining an activated precursor; mixing the activated precursor with a second solvent in a certain proportion, and performing stirring leaching treatment to obtain a leaching solution containing metals; and the grinding aid comprises at least one of an ammonium salt and an aqueous metal halide. The recycling method can achieve a metal recovery rate of more than 99% for lithium, cobalt, nickel and manganese.

Description

Technical Field

[0001] This application relates to the field of solid waste resource utilization and new energy material recycling technology, and in particular to a method for recycling valuable metals from electronic waste. Background Technology

[0002] With the explosive growth of the global new energy industry, lithium-ion batteries (LIBs) are increasingly used in electric vehicles and portable electronic devices. However, limited by the cycle life of electrode materials and lattice collapse during charge and discharge, lithium-ion batteries inevitably reach the end of their lifespan. Piezoelectric catalysis, as an emerging technology, converts mechanical energy into electrical potential energy to drive redox reactions, providing a new approach for metal recycling. However, existing piezoelectric catalysts are mostly perovskite ceramic materials containing lead (such as PZT) or barium / titanium (such as BaTiO3). When applied to battery recycling, their own metal ions are released into the leachate, leading to a decrease in the purity of the recycled products and the introduction of secondary metal pollution. In addition, some piezoelectric materials have poor thermal stability under high-energy mechanical forces such as ball milling and are prone to deactivation. Therefore, a green and efficient method for recycling valuable metals from electronic waste is urgently needed. Summary of the Invention

[0003] The main objective of this application is to propose a method for recycling valuable metals from electronic waste, aiming to solve the problem of secondary metal pollution caused by existing piezoelectric catalytic metal recycling methods.

[0004] To achieve the above objectives, the method for recycling valuable metals from electronic waste proposed in this application includes:

[0005] Electronic waste powder, boron nitride, grinding aid and first solvent are mixed in proportion, and mechanical stress is applied to grind them to obtain an activated precursor. The activated precursor and the second solvent were mixed in a certain proportion and subjected to stirring and leaching treatment to obtain a leachate containing metal. The grinding aid includes at least one of ammonium salts and aqueous metal halides.

[0006] Preferably, the boron nitride includes at least one of hexagonal boron nitride, cubic boron nitride, wurtzite boron nitride, amorphous boron nitride, or nanosheets thereof after exfoliation.

[0007] Preferably, the ammonium salt includes at least one of ammonium chloride, ammonium persulfate, ammonium bromide, ammonium iodide, ammonium sulfate, ammonium oxalate, ammonium citrate, and ammonium nitrate.

[0008] Preferably, the aqueous metal halide includes at least one of magnesium chloride hexahydrate, aluminum chloride hexahydrate, and ferric chloride hexahydrate.

[0009] Preferably, the mass ratio of the electronic waste powder to the boron nitride is 1~30:1; The mass ratio of the electronic waste powder to the grinding aid is 1~10:1; The amount of the first solvent added is 0 to 10% of the sum of the mass of the electronic waste powder, the boron nitride, and the grinding aid.

[0010] Preferably, the method of applying mechanical stress for grinding includes at least one of ball milling, vibratory milling, ultrasonication, friction stirring, or air jet milling; Preferably, the method of applying mechanical stress for grinding is ball milling, wherein the ball milling speed is 200~1000 rpm and the time is 0.5~6 h; Preferably, the grinding jar and grinding balls used in the ball mill are made of zirconium oxide, corundum, stainless steel or tungsten carbide.

[0011] Preferably, the second solvent includes at least one of deionized water, sulfuric acid solution, or nitric acid solution; The solid-liquid ratio of the activated precursor to the second solvent is 5~100 g / L, and the stirring speed is 300~700 rpm.

[0012] Preferably, the electronic waste powder is obtained by processing the positive and negative electrode materials of waste lithium-ion batteries; The cathode material of the waste lithium-ion batteries includes at least one of lithium cobalt oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, and lithium nickel oxide.

[0013] Preferably, the method for processing the positive electrode material of the battery includes: soaking the recycled waste lithium battery in a NaCl solution with a concentration of 10% to 100% for 12 to 14 hours, drying it, and then disassembling and separating it manually or mechanically; subsequently calcining it at 500 to 800°C for 0.5 to 8 hours, and finally grinding and sieving it to obtain the electronic waste powder.

[0014] The beneficial effects of this application are: (1) The method for recycling valuable metals from electronic waste proposed in this application introduces ammonium salt as a bifunctional agent. On the one hand, during the grinding process, the ammonium salt acts as a "molecular wedge" inserted between boron nitride layers to assist in physical stripping, significantly reducing the thickness of boron nitride and exposing more active edges, thereby greatly enhancing the piezoelectric response and built-in electric field strength of boron nitride. On the other hand, the enhanced piezoelectric field promotes the separation of electron-hole pairs, generating a large number of active oxygen species (•OH, O2). As a redox "engine", it can efficiently break metal-oxygen bonds at room temperature and pressure, significantly reducing the reaction energy barrier.

[0015] (2) Under continuous mechanical force and local hot spots, ammonium salts decompose in situ to produce highly reactive acidic gases (such as HCl) and coordination gases (such as NH3). This in-situ generated "acidic / complexing atmosphere" can rapidly combine with metal ions activated by the piezoelectric effect (such as forming [CoCl4)). 2- (or ammonia complex), preventing metal ions from returning to their metastable state, thereby achieving efficient dissolution of metals without the addition of large amounts of strong acids and bases.

[0016] (3) Using metal-free boron nitride as a catalyst avoids the risk of secondary heavy metal pollution introduced by traditional piezoelectric ceramics (such as lead- and barium-containing materials). No highly toxic fluorides or excessive strong acids are introduced throughout the process. Experiments show that the system can achieve a recovery rate of up to 99% for high-value metals such as lithium, cobalt, nickel, and manganese, realizing the clean, efficient, and low-carbon utilization of waste lithium battery resources.

[0017] (4) This invention couples material crushing, catalyst activation, redox reaction and chemical conversion into a single mechanical chemical reactor. The process is short, simple to operate and easy to scale up for industrial production. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating the method for recycling valuable metals from electronic waste provided in this application.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0024] With the explosive growth of the global new energy industry, lithium-ion batteries (LIBs) are increasingly used in electric vehicles and portable electronic devices. However, limited by the cycle life of electrode materials and lattice collapse during charging and discharging, lithium-ion batteries inevitably reach the end of their lifespan. It is predicted that by 2030, the global amount of waste lithium-ion batteries will exceed 11 million tons. If these waste lithium batteries are not properly disposed of, they will not only cause serious heavy metal and organic pollution but also represent a huge waste of resources. Therefore, developing efficient and green recycling technologies for waste lithium-ion batteries has become an urgent need for the industry.

[0025] Currently, recycling technologies for spent lithium-ion batteries mainly include pyrometallurgy, hydrometallurgy, and direct remediation. While pyrometallurgy is a mature process that requires no fine pretreatment, it typically requires temperatures above 1400°C, resulting in huge energy consumption and the emission of toxic gases (such as HF and dioxins). Direct remediation, although able to preserve the material's crystal structure, has extremely high requirements for the purity, composition, and consistency of residual structure of the raw materials, making it difficult to adapt to the diverse sources of spent lithium-ion batteries. Hydrometallurgy is currently the mainstream technology, using acid-base reagents to convert metals into ionic states. However, traditional hydrometallurgical processes usually require the use of strong inorganic acids (such as sulfuric acid and hydrochloric acid) and must add large amounts of expensive chemical reagents to assist in the treatment of sparingly soluble metals (such as Co). 3+ Mn 4+The reduction leaching of organic acids (such as citric acid) not only leads to high reagent costs but also generates large amounts of difficult-to-treat acidic wastewater. Although organic acids (such as citric acid) are considered green alternatives, their slow kinetics still require redox aids, failing to fundamentally resolve the contradiction between cost and efficiency.

[0026] In recent years, mechanochemical methods have attracted attention due to their solid-state reaction and low solvent requirements. Meanwhile, piezoelectric catalysis, as an emerging technology, converts mechanical energy into electrical potential energy to drive redox reactions, providing a new approach for metal recovery. However, existing piezoelectric catalysts are mostly perovskite-type ceramic materials containing lead (such as PZT) or barium / titanium (such as BaTiO3). When applied to battery recycling, the metal ions of these catalysts are released into the leachate, leading to a decrease in the purity of the recovered product and the introduction of secondary metal pollution. Furthermore, some piezoelectric materials exhibit poor thermal stability under high-energy mechanical forces such as ball milling, making them prone to deactivation. Therefore, there is an urgent need in this field to develop a novel catalytic system that is free of interfering metal ions, has high thermal stability, and exhibits strong piezoelectric response. Through the synergistic effect of mechanochemical and piezoelectric catalysis, a green and efficient recovery of high-value metals from spent lithium batteries can be achieved without relying on large amounts of chemical reducing agents.

[0027] Based on this, this application proposes a method for recycling valuable metals from electronic waste, comprising: S1. Electronic waste powder, boron nitride, grinding aid and first solvent are mixed in proportion and ground by mechanical stress to obtain activated precursor.

[0028] Using metal-free boron nitride as a catalyst avoids the risk of secondary heavy metal pollution introduced by traditional piezoelectric ceramics (such as lead- and barium-containing materials). The entire process does not introduce highly toxic fluorides or excessive strong acids. Experiments show that this system can achieve a recovery rate of up to 99% for high-value metals such as lithium, cobalt, nickel, and manganese, realizing the clean, efficient, and low-carbon utilization of waste lithium battery resources.

[0029] In some embodiments, boron nitride includes at least one of hexagonal boron nitride (h-BN), cubic boron nitride (c-BN), wurtzite boron nitride (w-BN), amorphous boron nitride, or exfoliated nanosheets thereof.

[0030] In some embodiments, the grinding aid includes at least one of ammonium salts and hydrated metal halides. Further, the ammonium salt includes at least one of ammonium chloride, ammonium persulfate, ammonium bromide, ammonium iodide, ammonium sulfate, ammonium oxalate, ammonium citrate, and ammonium nitrate; the hydrated metal halide includes at least one of magnesium chloride hexahydrate, aluminum chloride hexahydrate, and ferric chloride hexahydrate.

[0031] During the grinding process, ammonium salts act as "molecular wedges" inserted between boron nitride layers, assisting in physical exfoliation, significantly reducing the thickness of boron nitride and exposing more active edges, thus greatly enhancing the piezoelectric response and built-in electric field strength of boron nitride. On the other hand, the enhanced piezoelectric field promotes the separation of electron-hole pairs, generating a large number of reactive oxygen species (•OH, O2). As a redox "engine", it can efficiently break metal-oxygen bonds at room temperature and pressure, significantly reducing the reaction energy barrier.

[0032] Furthermore, under sustained mechanical force and localized hot spots, ammonium salts decompose in situ to produce highly reactive acidic gases (such as HCl) and coordination gases (such as NH3). This in-situ generated "acidic / complexing atmosphere" can rapidly combine with piezoelectrically activated metal ions (such as forming [CoCl4)). 2- (or ammonia complex), preventing metal ions from returning to their metastable state, thereby achieving efficient dissolution of metals without the addition of large amounts of strong acids and bases.

[0033] In some embodiments, the mass ratio of electronic waste powder to boron nitride is 1 to 30:1. For example, the mass ratio of electronic waste powder to boron nitride can be 1:1, 5:1, 10:1, 15:1, 20:1, 25:1, or 30:1. The mass ratio of electronic waste powder to grinding aid is 1 to 10:1. For example, the mass ratio of electronic waste powder to grinding aid can be 1:1, 2:1, 5:1, or 10:1, etc.

[0034] The first solvent need only be able to disperse the mixture. For example, the first solvent may include one or more of ethanol, deionized water, methanol, or acetone. The amount of the first solvent added is 0 to 10% of the sum of the mass of the electronic waste powder, boron nitride, and grinding aid. For example, the amount of the first solvent added is 0, 1%, 5%, or 10% of the total mass of the electronic waste powder, boron nitride, and grinding aid.

[0035] In some embodiments, the method of applying mechanical stress for grinding includes at least one of ball milling, vibratory milling, ultrasonication, friction stirring, or air jet milling. Preferably, the method of applying mechanical stress for grinding is ball milling, with a milling speed of 200-1000 rpm. For example, the milling speed can be 200 rpm, 400 rpm, 600 rpm, 800 rpm, or 1000 rpm. The milling time is 0.5-6 hours. For example, the milling time can be 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours. The material of the milling jar and grinding balls used in the ball milling process is selected from zirconium oxide, corundum, stainless steel, or tungsten carbide.

[0036] In some embodiments, the electronic waste powder is obtained by processing the positive and negative electrode materials of waste lithium-ion batteries. Specifically, the positive and negative electrodes of the waste lithium-ion batteries are coated with active materials, such as at least one of lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), ternary materials (lithium nickel cobalt manganese oxide NCM or lithium nickel cobalt aluminum oxide NCA, etc.), lithium manganese oxide (LiMn2O4), or lithium nickel oxide (LiNiO2).

[0037] In some embodiments, the method for processing the positive electrode material of spent lithium batteries includes: S11. Soak the recycled waste lithium batteries in a 10%~100% NaCl solution for 12~14 hours, dry them, and then disassemble and separate them manually or mechanically.

[0038] The concentration of NaCl can be 10%, 20%, 50%, 80%, or 100%, etc. The soaking time can be 12 h, 13 h, or 14 h, etc.

[0039] S12, then calcined at 500~800℃ for 0.5~8 h, and finally ground and sieved to obtain the electronic waste powder.

[0040] The calcination temperature can be 500℃, 600℃, 700℃, or 800℃, etc. The calcination time can be 0.5h, 1h, 2h, 4h, or 8h, etc. Calcination can be carried out in a muffle furnace.

[0041] S2. The activated precursor and the second solvent are mixed in proportion and subjected to stirring and leaching treatment to obtain a leachate containing metal.

[0042] In some embodiments, the second solvent includes at least one of deionized water, sulfuric acid solution, or nitric acid solution. The solid-liquid ratio of the activated precursor to the second solvent is 5 to 100 g / L. For example, the solid-liquid ratio of the activated precursor to the second solvent is 5 g / L, 10 g / L, 50 g / L, or 100 g / L, etc.

[0043] In some embodiments, the stirring speed during the stirred leaching process is 300 to 700 rpm. For example, the stirring speed can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, or 700 rpm, etc.

[0044] The following specific examples provide further details.

[0045] Example 1 This embodiment provides a method for recycling waste lithium cobalt oxide (LiCoO2) batteries. The recycling method includes the following steps: (1) Pretreatment: The waste lithium cobalt oxide batteries were soaked in a saturated NaCl solution for 24 h. Then they were taken out and dried in an oven at 55°C. After that, the dried lithium-ion battery metal casing was cut open with scissors to obtain the internal positive electrode, negative electrode and separator materials. The strip of positive electrode material was cut into small rectangular blocks, placed in a muffle furnace and calcined at 600°C for 2 h to obtain lithium cobalt oxide powder.

[0046] (2) Grinding: The obtained lithium cobalt oxide powder is ground and sieved and then used as raw material for subsequent processes.

[0047] (3) Metal extraction: a) Take 10 g of lithium cobalt oxide powder, 1 g of hexagonal boron nitride (h-BN), 5 g of ammonium chloride and 18 mL of deionized water and mix them; b) Pour into a 100 mL zirconium oxide container (ball-to-material ratio 15:1) and grind at 500 rpm for 6 h; (4) Metal separation: The lithium-ion-rich leachate was mixed with 640 mL of deionized water and stirred at 350 rpm to obtain dissociated metal. The metal ion concentration was determined by ICP-OES.

[0048] Example 2 This embodiment provides a method for recycling waste lithium iron phosphate (LiFePO4) batteries. This recycling method is the same as that in Embodiment 1, except that the electronic waste powder in the pretreatment step is lithium iron phosphate battery powder.

[0049] Example 3 This embodiment provides a method for recycling waste nickel cobalt manganese oxide (NCM) batteries. This recycling method is the same as that in Embodiment 1, except that the electronic waste powder in the pretreatment step is nickel cobalt manganese oxide (NCM) battery powder.

[0050] Example 4 This embodiment provides a method for recycling waste lithium cobalt oxide batteries. This recycling method is the same as that in Embodiment 1, except that the ball milling time in the metal extraction step is 4 hours.

[0051] Example 5 This embodiment provides a method for recycling waste lithium cobalt oxide batteries. This recycling method is the same as that in Embodiment 1, except that the ball milling speed is 700 rpm in the metal extraction step.

[0052] Example 6 This embodiment provides a method for recycling waste lithium cobalt oxide batteries. This recycling method is the same as that in Embodiment 1, except that the amount of hexagonal boron nitride used is 3 g.

[0053] Example 7 This embodiment provides a method for recycling spent lithium cobalt oxide batteries, which is the same as in Embodiment 1, except that the amount of ammonium chloride used is 1g, providing a low-content gas atmosphere in the ball milling system. During the ball milling process, ammonium chloride undergoes thermal decomposition, providing a low-concentration mixed gas atmosphere of ammonia and hydrogen chloride.

[0054] Comparative Example 1 This comparative example provides a method for recycling waste lithium cobalt oxide batteries, which is the same as that in Example 1, except that boron nitride is not added in the metal extraction step.

[0055] Comparative Example 2 This comparative example provides a method for recycling waste lithium cobalt oxide batteries, which is the same as that in Example 1, except that ammonium salts are not added in the metal extraction step.

[0056] Comparative Example 3 This comparative example provides a method for recycling waste lithium cobalt oxide batteries, which is the same as that in Example 1, except that boron nitride and ammonium salts are not added in the metal extraction step.

[0057] Comparative Example 4 This comparative example provides a method for recycling waste nickel-cobalt-manganese lithium (NCM) batteries. The recycling method includes the following steps: (1) Pretreatment: Waste lithium nickel cobalt manganese oxide (NCM) batteries were soaked in a saturated NaCl solution for 24 h. Then they were taken out and dried in an oven at 55°C. After that, the dried lithium-ion battery metal casing was cut open with scissors to obtain the internal positive electrode, negative electrode and separator materials. The strip of positive electrode material was cut into small rectangular blocks, placed in a muffle furnace and calcined at 600°C for 2 h to obtain lithium nickel cobalt manganese oxide powder.

[0058] (2) Grinding: The obtained lithium nickel cobalt manganese oxide powder is ground and sieved and then used as raw material for subsequent processes.

[0059] (3) Metal extraction: a) Take 10 g of lithium nickel cobalt manganese oxide powder, 1 g of hexagonal boron nitride (h-BN), 5 g of ammonium chloride, 2 g of ascorbic acid (solid hole sacrificial agent) and 20 mL of deionized water and mix them; b) Pour into a 100 mL zirconium oxide jar (ball-to-material ratio 15:1) and grind at 500 rpm for 6 h.

[0060] (4) Metal separation: The lithium-ion-rich leachate was mixed with 720 mL of deionized water and stirred at 350 rpm to obtain dissociated metal. The metal ion concentration was determined by ICP-OES.

[0061] The concentrations of lithium (Li), cobalt (Co), nickel (Ni), and manganese (Mn) ions in the leachates obtained in Examples 1-7 and Comparative Examples 1-4 were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), and the leaching recovery rates of each metal element were calculated. The test results are shown in Table 1.

[0062] Table 1. Metal leaching recovery rates of different embodiments and comparative examples

[0063] As shown in Table 1, the recovery method provided in this application achieves metal recovery rates of over 99% for lithium, cobalt, nickel, and manganese, demonstrating the superiority of the mechanochemical synergistic piezoelectric catalysis method for recovering high-value metals and effectively improving resource utilization. Furthermore, when processing different systems such as lithium cobalt oxide, lithium iron phosphate, and ternary materials, the recovery rates of the target metals (Li, Co, Ni, Mn) consistently reach over 99%, significantly better than the control group lacking boron nitride or ammonium salts, fully confirming the superiority of the "mechanochemical synergistic piezoelectric catalysis" system. The key to the success of this method lies in using mechanical ball milling as the driving force, forcing the boron nitride lattice to distort and form a high-intensity internal polarized electric field, promoting efficient electron-hole pair separation; the generated active electrons and active oxygen species directionally attack the cathode material lattice, breaking the metal-oxygen (MO) chemical bond, reducing the insoluble high-valence metal oxides to easily soluble low-valence ions, thereby achieving efficient leaching.

[0064] In this process, the innovatively introduced ammonium salt (such as ammonium chloride) plays a crucial "molecular wedge" synergistic role. Under the localized hot spots and mechanical forces generated by ball milling, ammonium chloride undergoes reversible thermal decomposition (NH4Cl). The gaseous small molecules generated by NH3 + HCl readily penetrate into the interlayer gaps of boron nitride. When the gas recombines within the confined space to form microcrystals or undergoes a phase transition, it is accompanied by a dramatic volume expansion. This in-situ generated enormous expansion pressure effectively expands and peels the bulk boron nitride into few-layer or even single-layer boron nitride nanosheets, thereby significantly exposing more active edges and enhancing piezoelectric response performance, ultimately achieving in-situ activation of the catalyst and efficient recovery of metal resources.

[0065] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for recycling valuable metals from electronic waste, characterized in that, include: Electronic waste powder, boron nitride, grinding aid and first solvent are mixed in proportion, and mechanical stress is applied to grind them to obtain an activated precursor. The activated precursor and the second solvent were mixed in a certain proportion and subjected to stirring and leaching treatment to obtain a leachate containing metal. The grinding aid includes at least one of ammonium salts and aqueous metal halides.

2. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The boron nitride includes at least one of hexagonal boron nitride, cubic boron nitride, wurtzite boron nitride, amorphous boron nitride, or nanosheets thereof after exfoliation.

3. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The ammonium salt includes at least one of ammonium chloride, ammonium persulfate, ammonium bromide, ammonium iodide, ammonium sulfate, ammonium oxalate, ammonium citrate, and ammonium nitrate.

4. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The hydrous metal halide includes at least one of magnesium chloride hexahydrate, aluminum chloride hexahydrate, and ferric chloride hexahydrate.

5. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The mass ratio of the electronic waste powder to the boron nitride is 1~30:1; The mass ratio of the electronic waste powder to the grinding aid is 1~10:1; The amount of the first solvent added is 0 to 10% of the sum of the mass of the electronic waste powder, the boron nitride, and the grinding aid.

6. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The method of applying mechanical stress for grinding includes at least one of ball milling, vibratory milling, ultrasonication, friction stirring, or air jet milling.

7. The method for recycling valuable metals from electronic waste as described in claim 6, characterized in that, The method of applying mechanical stress for grinding is ball milling, wherein the ball milling speed is 200~1000 rpm and the time is 0.5~6 h; Preferably, the grinding jar and grinding balls used in the ball mill are made of zirconium oxide, corundum, stainless steel or tungsten carbide.

8. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The second solvent includes at least one of deionized water, sulfuric acid solution, or nitric acid solution; The solid-liquid ratio of the activated precursor to the second solvent is 5~100 g / L, and the stirring speed is 300~700 rpm.

9. The method for recycling valuable metals from electronic waste as described in claim 1, characterized in that, The electronic waste powder is obtained by processing the positive and negative electrode materials of waste lithium-ion batteries; The cathode material of the waste lithium-ion batteries includes at least one of lithium cobalt oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, and lithium nickel oxide.

10. The method for recycling valuable metals from electronic waste as described in claim 9, characterized in that, The method for processing the positive electrode material of the waste lithium battery includes: soaking the recycled waste lithium battery in a 10%~100% NaCl solution for 12~14 h, drying it, and then disassembling and separating it manually or mechanically; then calcining it at 500~800℃ for 0.5~8 h, and finally grinding and sieving it to obtain the electronic waste powder.

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