Recovery method of solid-state battery material

Abstract

The invention discloses a solid-state battery material recovery method, and relates to the technical field of solid-state battery recovery, and the method comprises the following steps: heating first mixed powder in air to obtain second mixed powder; the second mixed powder is leached through organic weak acid and a reducing agent, first leaching residues and first leaching liquid are obtained, and then the first leaching liquid is processed through a wet process; the first leaching residues are leached with sulfuric acid, and second leaching residues and second leaching liquid are obtained; precipitating lanthanum oxalate from the second leaching solution to obtain a first mixed solution; precipitating lithium carbonate from the first mixed solution; the second leaching residues are leached with hydrofluoric acid, and third leaching liquid and carbon are obtained; precipitating zirconium oxalate from the third leaching solution to obtain a second mixed solution, and concentrating the second mixed solution to obtain fluosilicic acid. Through heating, step-by-step leaching, a wet process, precipitation separation and the like, valuable metals, silicon and carbon are efficiently separated and recycled, copper and aluminum impurities are removed, the resource utilization rate is effectively increased, and the feasibility of industrialization is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery recycling technology, and more specifically to a method for recycling solid-state battery materials. Background Technology

[0002] Solid-state lithium-ion batteries (SSDs) have become an important development direction in electric vehicles, energy storage, 3C products, and the low-altitude economy due to their high energy density of 300Wh / kg to 500Wh / kg, excellent safety after eliminating organic electrolytes, and good low-temperature adaptability. Among them, SSDs using LLZO (lithium lanthanum zirconium oxide) as the solid electrolyte are the mainstream category in current commercial applications. As the market size of LLZO-type solid-state batteries gradually expands, the valuable metals contained in them after disposal have extremely high resource recycling value—including lithium, nickel, cobalt, and manganese from ternary cathodes, and lithium, lanthanum, and zirconium from LLZO electrolytes. The efficient recycling of these metals can not only reduce dependence on primary mineral resources, but also directly relate to the sustainable development of the industry, becoming a key issue of current industry concern.

[0003] However, current recycling technology for LLZO solid-state batteries still faces many bottlenecks: Firstly, the mixed powder recovered from spent LLZO solid-state batteries has an extremely complex composition. Besides the LLZO solid electrolyte and nickel-cobalt-manganese-lithium ternary cathode material, it also contains silicon-carbon anode material and copper and aluminum impurities. The physicochemical properties of these components differ greatly, and they easily form complex mixed systems when coexisting, posing a significant challenge to the precise separation of valuable metals. Traditional pyrometallurgical recovery methods are energy-intensive, prone to secondary pollution, and difficult to achieve precise separation of valuable elements.

[0004] Secondly, existing technologies mostly focus on the recycling of single components. For example, they only design regeneration processes such as grinding, calcination, and soaking in specific solvents for LLZO solid electrolytes, or they only focus on the metal extraction of nickel-cobalt-manganese-lithium ternary cathode materials. They ignore the objective scenario that LLZO solid electrolytes, nickel-cobalt-manganese-lithium ternary cathode materials, silicon-carbon anode materials, copper and aluminum impurities, etc., coexist in actual waste solid battery powders. This results in the inability to simultaneously recycle components such as lithium, nickel, cobalt, manganese, lanthanum, zirconium, silicon and carbon, and extremely low resource utilization. Third, although some technologies attempt to handle mixed components, the leaching and separation systems lack targeted design. Not only are lanthanum and zirconium in LLZO solid electrolytes and nickel, cobalt, and manganese in nickel-cobalt-manganese-lithium ternary cathode materials difficult to achieve efficient fractional separation, often resulting in metal cross-contamination; moreover, silicon and carbon resources in silicon-carbon anodes are not effectively utilized, and copper and aluminum impurities are not specifically removed, leading to low resource utilization and easy secondary pollution.

[0005] In summary, existing technologies cannot effectively solve the problem of efficient separation and recovery of components in a mixed system of LLZO solid electrolyte, nickel-cobalt-manganese-lithium ternary cathode material, silicon-carbon anode material, and copper-aluminum impurities in LLZO solid batteries, resulting in low industrialization feasibility and serious resource waste. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a method for recycling solid-state battery materials. Through heating, stepwise leaching, and combined with wet processes and precipitation separation, various valuable metals and silicon carbon are efficiently separated and recovered, and copper and aluminum impurities are removed. This not only effectively improves resource utilization, but also significantly enhances the feasibility of industrialization.

[0007] This invention provides a method for recycling solid-state battery materials, comprising the following steps: S1. A first mixed powder is recovered from the solid-state battery. The first mixed powder contains lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material, silicon carbon anode material and copper and aluminum impurities. S2. The first mixed powder is placed in an air atmosphere and heated to obtain the second mixed powder; S3. The second mixed powder is leached with an organic weak acid solution and a reducing agent to separate the first leaching residue and the first leaching solution containing lithium, nickel, cobalt, manganese, copper and aluminum. Then, lithium carbonate, nickel compound, cobalt compound and manganese compound are extracted from the first leaching solution by a wet process. S4. Leach the first leaching residue with sulfuric acid solution to separate the second leaching residue and the second leaching solution containing lithium and lanthanum; add oxalic acid or oxalate to the second leaching solution to separate the lanthanum oxalate precipitate and the first mixed solution containing lithium; adjust the pH of the first mixed solution to alkaline and heat it, add sodium carbonate or carbon dioxide to react and obtain lithium carbonate precipitate. S5. The second leaching residue is leached with hydrofluoric acid solution to separate a third leaching solution and a carbon-containing third leaching residue; oxalic acid or oxalate is added to the third leaching solution to separate zirconium oxalate precipitate and a second mixed solution containing fluorine silicon; the second mixed solution is concentrated to obtain fluorosilicic acid.

[0008] Specifically, the first mixed powder recovered from the solid-state battery includes: The solid-state battery is subjected to discharge treatment, crushing treatment, drying treatment, grinding treatment and sorting treatment in sequence to obtain the first mixed powder.

[0009] Specifically, step S2 includes: The first mixed powder is heated in an air atmosphere at 100℃~200℃ for 1h~5h to obtain the second mixed powder.

[0010] Specifically, in step S3, the solute of the organic weak acid solution is one or more of oxalic acid, citric acid, formic acid, acetic acid, and tartaric acid, the concentration range of the organic weak acid solution is 0.5 mol / L to 4 mol / L, and the solid-liquid ratio between the second mixed powder and the organic weak acid solution is 10 g / L to 200 g / L. The leaching temperature range for the second mixed powder is 25℃~60℃.

[0011] Specifically, in step S3, the reducing agent is one or more of hydrogen peroxide, sodium sulfite, and sodium bisulfite; Based on the volume of the organic weak acid solution, the amount of reducing agent is determined according to the following range: The dosage range for solid reducing agents is 1 g / L to 200 g / L, and the dosage range for liquid reducing agents is 0.1 mol / L to 5 mol / L.

[0012] Specifically, the extraction of lithium carbonate, nickel compound, cobalt compound, and manganese compound from the first leachate using a wet process includes: S31. Add di(2-ethylhexyl) phosphate to the first leachate for extraction treatment, and separate the first extract containing manganese, copper and aluminum and the first raffinate containing lithium, nickel and cobalt. S32. Add sulfuric acid solution to the first extract for back-extraction to separate manganese sulfate solution; the manganese sulfate solution is then evaporated and crystallized to prepare battery-grade manganese sulfate product. S33. The first raffinate is subjected to two fractional extractions using 2-ethylhexyl phosphate mono-2-ethylhexyl ester to separate a second extract containing cobalt, a third extract containing nickel, and a second raffinate containing lithium. S34. The second extract and the third extract are back-extracted with sulfuric acid solution to separate cobalt sulfate solution and crude nickel sulfate solution. S35. The crude nickel sulfate solution was purified by extraction with bis(2,4,4-trimethylpentyl)phosphonic acid to obtain a purified nickel sulfate solution. S36. The cobalt sulfate solution and the nickel sulfate solution are respectively subjected to evaporation and crystallization treatment to prepare battery-grade cobalt sulfate product and battery-grade nickel sulfate product; S37. Adjust the pH of the second raffinate to 10-12, control the reaction temperature range to 80℃-100℃, add sodium carbonate or carbon dioxide to react, and separate the lithium carbonate product after the reaction is completed.

[0013] Specifically, in step S4, the concentration range of the sulfuric acid solution is 1 mol / L to 5 mol / L, the solid-liquid ratio between the first leaching residue and the sulfuric acid solution is 10 g / L to 200 g / L, and the leaching temperature range of the first leaching residue is 25℃ to 80℃.

[0014] Specifically, in step S4, the pH of the first mixture is adjusted to 10-12 and heated to 80-100°C. Sodium carbonate or carbon dioxide is added to react and lithium carbonate precipitate is obtained.

[0015] Specifically, in step S5, the mass concentration of the hydrofluoric acid solution ranges from 10% to 30%, and the leaching temperature of the second leaching residue ranges from 60°C to 80°C.

[0016] Specifically, in step S5, the second mixture is concentrated at 60°C to 80°C.

[0017] Compared with the prior art, the beneficial effects of the present invention are: First, a first mixed powder is recovered from the solid-state battery. The powdered recovered material has effectively broken down the components, so that the target components are fully exposed in particulate form, which facilitates subsequent heating, leaching, separation and other steps, and lays the foundation for efficient recovery. Next, heating in an air atmosphere can effectively weaken the adhesion of residual binders in lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material, and silicon-carbon anode material, which is beneficial to improving subsequent leaching efficiency; it can also slightly oxidize the elemental silicon in silicon-carbon anode material (generating SiO2, which is easier to process later); and it can also relax the crystal structure of nickel cobalt manganese lithium ternary cathode material and lithium lanthanum zirconium oxide solid electrolyte, reducing the subsequent acid dissolution activation energy. Next, given the difference in solubility of lithium lanthanum zirconium oxide solid electrolyte and nickel-cobalt-manganese lithium ternary cathode material in weak organic acids, the core valuable metals (lithium, nickel, cobalt, and manganese) and metal impurities (copper and aluminum) in the nickel-cobalt-manganese lithium ternary cathode material are preferentially leached out through the combined action of the weak organic acid solution and the reducing agent to form the first leachate. Lithium carbonate, nickel compounds, cobalt compounds, and manganese compounds are then extracted from this leachate through a wet process, while copper and aluminum impurities are removed during the wet process. The lithium lanthanum zirconium oxide solid electrolyte (resistant to weak organic acids) and silicon-carbon anode material (poorly soluble in weak organic acids) remain as the first leachate residue. This achieves precise separation of the lithium lanthanum zirconium oxide solid electrolyte and the nickel-cobalt-manganese lithium ternary cathode material, providing a high-purity leachate for the extraction of battery-grade compounds through wet processes (extraction, crystallization, etc.), ensuring the purity of subsequent products, and solving the problem of metal cross-contamination in traditional processes. Then, the crystal structure of the lithium lanthanum zirconium oxide solid electrolyte in the first leaching residue is destroyed by sulfuric acid solution (strong acid), dissolving Li2O and La2O3 (generating Li2SO4 and La2(SO4)3) to form the second leaching solution. ZrO2 in the lithium lanthanum zirconium oxide solid electrolyte and the silicon-carbon anode material are poorly soluble in sulfuric acid solution and remain as the second leaching residue. This achieves a secondary separation of (Li, La) and (Zr, silicon-carbon), which not only facilitates the efficient recovery of high-value La (lanthanum oxalate) and Li (lithium carbonate) from LLZO, avoiding the waste of valuable metals in LLZO, but also paves the way for subsequent Zr and carbon recovery, further improving resource utilization. For the second leaching solution, La is first utilized... 3+ With C2O4 2- The property of generating sparingly soluble lanthanum oxalate allows for precise separation of La. Then, by adjusting the pH to alkaline, the common ion effect (sodium carbonate / CO2) is utilized to separate Li. + Precipitation in the form of lithium carbonate enables precise separation of La and Li; Finally, the second leaching residue was treated with hydrofluoric acid solution, and the H+ of the hydrofluoric acid was reduced. + First, erode and activate ZrO2 and silicon-carbon, then use hydrofluoric acid. - With Zr 4+ Si 4+ Formation of stable complex ions (ZrF6) 2- SiF6 2- This process dissolves ZrO2 and SiO2 to generate a third leaching solution. Carbon (mainly a mixture of conductive carbon and graphite) and residual binder are insoluble in HF, leaving behind the third leaching residue, thus achieving the final separation of (Zr, Si) and carbon. For the third leaching solution, ZrF6 is used... 2- With C2O4 2- The characteristic of generating sparingly soluble zirconium oxalate allows for the separation of Zr, followed by concentration of the fluorosilicic acid-containing mixture to obtain fluorosilicic acid. This achieves full component recovery, recovering Zr (zirconium oxalate) from LLZO, Si (fluorosilicic acid) from silicon-carbon, and carbon, while eliminating resource waste.

[0018] In summary, this invention uses a powdered recycled material—a first mixed powder—containing lithium lanthanum zirconium oxide solid electrolyte, nickel-cobalt-manganese-lithium ternary cathode material, silicon-carbon anode material, and copper and aluminum impurities as a base. The process involves sequentially heating the powder in air, leaching with organic weak acids and reducing agents, sulfuric acid leaching, and hydrofluoric acid leaching, combined with wet processing and precipitation separation. This efficiently separates and recovers various valuable metals and silicon-carbon, while also removing copper and aluminum impurities. This not only effectively improves resource utilization but also significantly enhances the feasibility of industrialization. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart of the solid-state battery material recycling method in an embodiment of the present invention; Figure 2 This is a schematic diagram of the wet process in an embodiment of the present invention. Detailed Implementation

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

[0022] This invention provides a method for recycling solid-state battery materials. Figure 1 A schematic flowchart of a method for recycling solid-state battery materials according to an embodiment of the present invention is shown, including the following steps: S1. A first mixed powder is recovered from the solid-state battery. The first mixed powder contains lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material, silicon carbon anode material and copper and aluminum impurities. The solid-state battery is a scrapped LLZO type solid-state battery, which uses lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode, silicon carbon anode, aluminum foil positive current collector, copper foil negative current collector, etc. Therefore, the first mixed powder recovered from the solid-state battery contains lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material, silicon carbon anode material and copper and aluminum impurities. The lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material and silicon carbon anode material usually also contain binder residues.

[0023] The recovered material in powder form—the first mixed powder—has effectively broken down each component, fully exposing the target component in particulate form. This facilitates subsequent heating, leaching, and separation steps, laying the foundation for efficient recovery.

[0024] Specifically, the first mixed powder recovered from the solid-state battery includes: The solid-state battery is subjected to discharge treatment, crushing treatment, drying treatment, grinding treatment and sorting treatment in sequence to obtain the first mixed powder; in addition to the first mixed powder, other by-products such as plastic separator, battery casing, copper foil, aluminum foil, etc. are also sorted out.

[0025] The process involves several steps: discharge treatment to eliminate residual energy in the solid-state battery, preventing short circuits and fires during subsequent crushing, and ensuring safety; crushing treatment to break down the solid-state battery structure into mixed blocks, initially separating auxiliary materials such as the casing and separator, creating conditions for subsequent processing; drying treatment to remove liquid electrolyte (currently, the widely used LLZO type solid-state batteries are semi-solid and still contain some liquid electrolyte) and moisture from the material, ensuring powder dispersibility during subsequent grinding; grinding treatment to separate the positive and negative electrode materials and solid electrolyte from the copper-aluminum current collector, creating particle size differences between the positive and negative electrode particles, solid electrolyte particles, copper-aluminum current collector particles, plastic separator particles, and battery casing particles, creating a basis for subsequent sorting based on physical property differences; and sorting treatment to separate the first mixed powder, plastic separator, battery casing, copper foil, aluminum foil, etc., with sorting processes including sieving, gravity separation, magnetic separation, specific gravity separation, and color sorting, achieving efficient resource recovery.

[0026] In the solid-state battery recycling process, discharge treatment, crushing treatment, drying treatment, grinding treatment and sorting treatment are all relatively mature methods in the current lithium battery recycling technology system. Each link is closely connected and together lays a solid foundation for the safe and efficient recycling of solid-state battery resources.

[0027] S2. The first mixed powder is placed in an air atmosphere and heated to obtain the second mixed powder; Heating in an air atmosphere can effectively weaken the adhesion of residual binders in lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material, and silicon-carbon anode material, which is beneficial to improving subsequent leaching efficiency; it can also slightly oxidize the elemental silicon in silicon-carbon anode material (generating SiO2, which is easier to process later); and it can also relax the crystal structure of nickel cobalt manganese lithium ternary cathode material and lithium lanthanum zirconium oxide solid electrolyte, reducing the subsequent acid dissolution activation energy.

[0028] Specifically, the first mixed powder is heated in an air atmosphere at 100℃~200℃ for 1h~5h to obtain the second mixed powder. 100℃~200℃ is a mild temperature range that can achieve the goals of weakening the binder, silicon oxidation, and crystal structure relaxation, while avoiding excessive oxidation or structural collapse of the target component (such as ternary materials) due to excessive temperature. The treatment time of 1h~5h can be flexibly adjusted according to the actual particle size distribution and component content of the first mixed powder to ensure that each effect is fully exerted, and finally, a stable second mixed powder with "high reactivity and easy separation" is obtained, which not only improves the target metal recovery rate, but also reduces the energy consumption and cost of recovery.

[0029] Optionally, the first mixed powder is heated in air at 100°C for 5 hours, or in air at 150°C for 3 hours, or in air at 200°C for 1 hour. Preferably, heating the first mixed powder in air at 150°C for 3 hours provides the best overall performance and the strongest versatility.

[0030] S3. The second mixed powder is leached with an organic weak acid solution and a reducing agent to separate the first leaching residue and the first leaching solution containing lithium, nickel, cobalt, manganese, copper and aluminum. Then, lithium carbonate, nickel compound, cobalt compound and manganese compound are extracted from the first leaching solution by a wet process. Given the difference in solubility of lithium lanthanum zirconium oxide solid electrolyte and nickel-cobalt-manganese lithium ternary cathode material in weak organic acids, the core valuable metals (lithium, nickel, cobalt, and manganese) and metal impurities (copper and aluminum) in the nickel-cobalt-manganese lithium ternary cathode material are preferentially leached out to form the first leachate through the combined action of the weak organic acid solution and the reducing agent. Lithium carbonate, nickel compounds, cobalt compounds, and manganese compounds are then extracted from this first leachate using a wet process, while copper and aluminum impurities are removed during the wet process. The lithium lanthanum zirconium oxide solid electrolyte (resistant to weak organic acids) and silicon-carbon anode material (poorly soluble in weak organic acids) remain as the first leachate residue. This achieves precise separation of the lithium lanthanum zirconium oxide solid electrolyte and the nickel-cobalt-manganese lithium ternary cathode material, providing a high-purity leachate for the extraction of battery-grade compounds through wet processes (extraction, crystallization, etc.) and ensuring the purity of subsequent products, thus solving the problem of metal cross-contamination in traditional processes.

[0031] In some specific embodiments, the solute of the organic weak acid solution is one or more of oxalic acid, citric acid, formic acid, acetic acid, and tartaric acid, the concentration range of the organic weak acid solution is 0.5 mol / L to 4 mol / L, the solid-liquid ratio between the second mixed powder and the organic weak acid solution is 10 g / L to 200 g / L, and the leaching temperature range of the second mixed powder is 25℃ to 60℃.

[0032] Solid-state batteries use LLZO solid electrolytes that are resistant to weak organic acids, while silicon-carbon anode materials are poorly soluble in weak organic acids. In contrast, nickel-cobalt-manganese-lithium ternary cathode materials are readily soluble in weak organic acids under the action of reducing agents. By selecting "mild weak organic acids" and "adaptive parameters," it can be ensured that only lithium, nickel, cobalt, manganese, and copper-aluminum impurities in the nickel-cobalt-manganese-lithium ternary cathode materials are leached out. The LLZO solid electrolyte and silicon-carbon anode material residues form the first leaching residue, completely avoiding the problem of "cross-dissolution between solid electrolytes and cathode materials" in traditional processes, thus laying the foundation for subsequent high-purity separation.

[0033] In this process, an organic weak acid solution with a concentration of 0.5 mol / L to 4 mol / L, combined with a reducing agent, can achieve a leaching rate of over 95% for nickel, cobalt, manganese, and lithium in the nickel-cobalt-manganese-lithium ternary cathode material, as well as complete leaching of copper and aluminum impurities. If the concentration is too low, the leaching of the nickel-cobalt-manganese-lithium ternary cathode material and copper and aluminum impurities will be insufficient; if the concentration is too high, reagents will be wasted and the load on subsequent treatments will increase. Optionally, the concentration of the organic weak acid solution can be 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, or 4 mol / L; preferably, the concentration of the organic weak acid solution is 2 mol / L, balancing leaching efficiency and usage cost.

[0034] A solid-liquid ratio of 10 g / L to 200 g / L is suitable for batch processing needs in industrial production, avoiding incomplete reactions due to an excessively high solid-liquid ratio or increased energy consumption due to an excessively low solid-liquid ratio. Optionally, the solid-liquid ratio between the second mixed powder and the organic weak acid solution can be 10 g / L, 50 g / L, 100 g / L, 150 g / L, or 200 g / L; preferably, the solid-liquid ratio between the second mixed powder and the organic weak acid solution is 100 g / L, which is suitable for the capacity of conventional industrial reactors, balancing batch processing and reaction adequacy, while maintaining low energy consumption.

[0035] The leaching temperature range is 25℃~60℃, meaning that high-temperature heating is not required, reducing energy consumption. It also avoids the decomposition of organic weak acids and the structural collapse of the LLZO solid electrolyte and silicon-carbon anode material caused by high temperatures, thus balancing efficient leaching with process stability. Optionally, the leaching temperature of the second mixed powder can be 25℃, 35℃, 45℃, 55℃, or 60℃; preferably, the leaching temperature of the second mixed powder is 45℃, because the leaching rate is relatively slow at 25℃ (requiring more than 8 hours), while the evaporation rate of organic weak acids increases at 60℃, and leaching can be completed in 3 hours at 45℃.

[0036] The preferred solutes for the organic weak acid solution are oxalic acid and citric acid (mixed in a 1:1 mass ratio). Oxalic acid's reducing properties can help dissolve high-valence metals, while citric acid has strong complexing ability. When mixed with a reducing agent, they can achieve a leaching rate of over 98% for nickel, cobalt, manganese, and lithium in ternary cathode materials.

[0037] In some specific embodiments, the reducing agent is one or more of hydrogen peroxide, sodium sulfite, and sodium bisulfite; based on the volume of the organic weak acid solution, the amount of the reducing agent is determined according to the following ranges: the amount of solid reducing agent ranges from 1 g / L to 200 g / L, and the amount of liquid reducing agent ranges from 0.1 mol / L to 5 mol / L.

[0038] Some metals (such as Co) in nickel-cobalt-manganese-lithium ternary cathode materials 3+ Mn 4+In its high oxidation state, it is poorly soluble in weak organic acids; reducing agents can reduce it to a more soluble low oxidation state (such as Co). 2+ Mn 2+ This effectively improves the leaching rate of valuable metals; at the same time, it controls the amount of reducing agent to avoid incomplete reduction or excessive residue that could damage subsequent processes, thus adapting to the flexibility requirements of different raw materials in industrial production.

[0039] The amount of solid reducing agent used (based on the volume of the organic weak acid solution) can be 1 g / L, 50 g / L, 100 g / L, 150 g / L, or 200 g / L. Preferably, the amount of solid reducing agent used is 50 g / L. The reduction efficiency of 1 g / L is relatively low, and 200 g / L is prone to producing a large amount of SO2 gas. The reduction rate of 50 g / L reaches 99% and the gas production is relatively small.

[0040] The amount of liquid reducing agent (based on the volume of the organic weak acid solution) can be 0.1 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L; preferably, the amount of liquid reducing agent is 1 mol / L. 0.1 mol / L has a relatively low reduction efficiency, 5 mol / L is prone to producing a large amount of oxygen, and 2 mol / L balances reduction efficiency and control of gas production.

[0041] The reducing agent is preferably hydrogen peroxide (with a concentration of 20wt%~30wt%, preferably 30wt%), which has a mild reaction, leaves no solid residue, and is easy to control at the endpoint. It can also form a synergistic leaching system with weak organic acids.

[0042] In some specific embodiments, the extraction of lithium carbonate, nickel compound, cobalt compound, and manganese compound from the first leachate by a wet process includes ( Figure 2 (A schematic diagram of the wet process in an embodiment of the present invention is shown). S31. Add di(2-ethylhexyl) phosphate to the first leachate for extraction treatment, and separate the first extract containing manganese, copper and aluminum and the first raffinate containing lithium, nickel and cobalt. Di(2-ethylhexyl) phosphate, also known as P204, is effective against Mn. 2+ Cu 2+ And Al 3+ Its extraction ability is far superior to that of Li + Ni 2+ Co 2+ —Through coordination with Mn 2+ Cu 2+ And Al 3+ It combines into the organic phase (first extract), while Li + Ni 2+ Co2+ It remains in the aqueous phase (first raffinate). Manganese, copper, and aluminum in the first leaching solution are preferentially separated by P204 to avoid interfering with the subsequent purification of lithium, nickel, and cobalt.

[0043] Specifically, the volume concentration of P204 is 10%~30%, the extraction ratio of O / A is 1:2~2:1, and the extraction temperature is 20℃~40℃.

[0044] S32. Add sulfuric acid solution to the first extract for back-extraction to separate manganese sulfate solution; the manganese sulfate solution is then evaporated and crystallized to prepare battery-grade manganese sulfate product. Sulfuric acid provides a high concentration of H+ + It competes with P204 for coordination sites, allowing Mn 2+ The solution is transferred from the organic phase to the aqueous phase, forming a pure manganese sulfate solution, while Cu... 2+ And Al 3+ It is then retained in the first extract, thus achieving Mn 2+ Purification and Cu 2+ And Al 3+ The removal of water and trace soluble impurities by evaporation and crystallization ensures the purity of manganese sulfate products—battery-grade manganese sulfate (MnSO4・H2O / MnSO4・5H2O, purity ≥99.9%).

[0045] S33. The first raffinate is subjected to two fractional extractions using 2-ethylhexyl phosphate mono-2-ethylhexyl ester to separate a second extract containing cobalt, a third extract containing nickel, and a second raffinate containing lithium. 2-Ethylhexyl phosphate mono-2-ethylhexyl ester, also known as P507, is used for two-stage fractional extraction when added to the first raffinate containing lithium, nickel, and cobalt. P507 is an acidic phosphorus extractant, and its extraction ability for metal ions exhibits significant selectivity with varying solution pH. The order of selectivity for metal ions by P507 is: Co... 2+ >Ni 2+ >Li + —First extraction prioritizes extracting Co. 2+ Enter the organic phase (second extract); after adjusting the pH conditions, perform a second extraction to extract Ni. 2+ Entering the organic phase (third extract); Li + Because of its weakest extraction ability, it remains in the aqueous phase (second raffinate).

[0046] Specifically, the first extraction involves adjusting the pH of the system to 3.0-4.5, allowing cobalt in the first raffinate to preferentially combine with P507 and enter the organic phase, resulting in a cobalt-containing second extract and a lithium-nickel-based raffinate. A second extraction is then performed using fresh P507 to extract the lithium-nickel-based raffinate, adjusting the pH to 4.5-5.5 to ensure sufficient extraction of nickel by P507 into the organic phase, resulting in a nickel-containing third extract and a lithium-containing second raffinate.

[0047] Furthermore, the volume concentration of P507 is 20%~45%, the first extraction ratio O / A is 1:1~3:1 to separate cobalt, the second extraction ratio O / A is 2:1~5:1 to enrich nickel, and the extraction temperature is 30~50℃.

[0048] In the lithium, nickel, and cobalt system, the individual separation of the three components was achieved, laying the foundation for the separate preparation of products.

[0049] S34. The second extract and the third extract are back-extracted with sulfuric acid solution to separate cobalt sulfate solution and crude nickel sulfate solution. Sulfuric acid provides a high concentration of H+ + High concentration of H + It will damage P507 and Co 2+ Ni 2+ The coordination bonds allow metal ions to enter the aqueous phase, forming cobalt sulfate solution and crude nickel sulfate solution (containing trace impurities).

[0050] S35. The crude nickel sulfate solution was purified by extraction with bis(2,4,4-trimethylpentyl)phosphonic acid to obtain a purified nickel sulfate solution. Bis(2,4,4-trimethylpentyl)phosphonic acid, also known as C272, exhibits a much higher selectivity for extracting trace impurity metal ions than Ni. 2+ It can specifically bind to impurities (such as Fe). 3+ Zn 2+ Ca 2+ (etc.) and enter the organic phase, while Ni 2+ Retained in the aqueous phase, Ni was achieved 2+ The nickel sulfate solution is deeply purified (impurity content ≤10ppm, meeting battery grade standards).

[0051] Specifically, the volume concentration of C272 is 5%~20%, the extraction ratio O / A is 1:3~3:1, and the extraction pH is controlled at 3.5~5.0 to effectively remove metal ion impurities.

[0052] S36. The cobalt sulfate solution and the nickel sulfate solution are respectively subjected to evaporation and crystallization treatment to prepare battery-grade cobalt sulfate product and battery-grade nickel sulfate product; By evaporating and removing the solvent water, the metal salt reaches a supersaturated state and crystals precipitate. Strict control of crystallization conditions (such as cooling rate and stirring speed) can avoid impurity encapsulation and ensure product purity, thus obtaining battery-grade cobalt sulfate (CoSO4・7H2O, purity ≥99.9%) and battery-grade nickel sulfate (NiSO4・6H2O, purity ≥99.9%).

[0053] S37. Adjust the pH of the second raffinate to 10-12, control the reaction temperature range to 80℃-100℃, add sodium carbonate or carbon dioxide to react, and separate the lithium carbonate product after the reaction is completed.

[0054] Adjusting the pH of the second raffinate to 10-12 using an alkali (such as sodium hydroxide) can make Li + Improved stability; the addition of sodium carbonate or carbon dioxide will produce a reaction (2Li + +Na₂CO₃→Li₂CO₃↓+2Na + or 2Li + +CO2+2OH - →Li2CO3↓+H2O), thus turning Li + It precipitates out in the form of lithium carbonate; the solubility of lithium carbonate (Li2CO3) decreases with increasing temperature. The reaction at 80℃~100℃ can promote the precipitation of Li2CO3, and the solubility of impurities is lower at high temperature, resulting in higher product purity and obtaining battery-grade lithium carbonate (Li2CO3, purity ≥99.5%).

[0055] This hydrometallurgical process achieves efficient separation of lithium, nickel, cobalt, and manganese (target metal yield ≥95%) through multi-stage extraction and back-extraction, and the product has high purity (meeting battery-grade standards). In addition, the extractants (P204, P507, C272) can be recycled (the organic phase after back-extraction can be regenerated and reused for extraction), which meets the requirements of green production in hydrometallurgy.

[0056] S4. Leach the first leaching residue with sulfuric acid solution to separate the second leaching residue and the second leaching solution containing lithium and lanthanum; add oxalic acid or oxalate to the second leaching solution to separate the lanthanum oxalate precipitate and the first mixed solution containing lithium; adjust the pH of the first mixed solution to alkaline and heat it, add sodium carbonate or carbon dioxide to react and obtain lithium carbonate precipitate. The crystal structure of the lithium lanthanum zirconium oxide solid electrolyte in the first leaching residue is destroyed by sulfuric acid solution (strong acid), dissolving Li₂O and La₂O₃ (generating Li₂SO₄ and La₂(SO₄)₃) to form the second leaching solution. ZrO₂ in the lithium lanthanum zirconium oxide solid electrolyte and the silicon-carbon anode material are poorly soluble in sulfuric acid solution and remain as the second leaching residue. This achieves a secondary separation of (Li, La) and (Zr, silicon-carbon), facilitating the efficient recovery of high-value La (lanthanum oxalate) and Li (lithium carbonate) from LLZO, avoiding waste of valuable metals in LLZO, and paving the way for subsequent Zr and carbon recovery, further improving resource utilization. For the second leaching solution, La is first utilized... 3+ With C2O4 2- The property of generating sparingly soluble lanthanum oxalate allows for precise separation of La. Then, by adjusting the pH to alkaline, the common ion effect (sodium carbonate / CO2) is utilized to separate Li. + Precipitation in the form of lithium carbonate enables precise separation of La and Li.

[0057] In some specific embodiments, the concentration of the sulfuric acid solution ranges from 1 mol / L to 5 mol / L, the solid-liquid ratio between the first leaching residue and the sulfuric acid solution is from 10 g / L to 200 g / L, and the leaching temperature of the first leaching residue ranges from 25°C to 80°C. In step S4, the ranges of parameters such as sulfuric acid solution concentration (1 mol / L to 5 mol / L), solid-liquid ratio (10 g / L to 200 g / L), and leaching temperature (25°C to 80°C) ensure that Li and La in LLZO are fully leached (leaching rate ≥90%), while avoiding the dissolution of ZrO2 and silicon-carbon anode material, thus creating conditions for the subsequent recovery of Zr and silicon-carbon.

[0058] The sulfuric acid solution concentration (1 mol / L to 5 mol / L) is sufficient to destroy the LLZO structure without excessively corroding the equipment or dissolving the target residue. Optionally, the concentration of the sulfuric acid solution can be 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L; preferably, the concentration of the sulfuric acid solution is 3 mol / L. 1 mol / L has relatively low leaching efficiency, while 5 mol / L requires strict control of the uniformity of the system temperature, otherwise it is easy to dissolve some ZrO2. 3 mol / L has high leaching efficiency and good process controllability.

[0059] The solid-liquid ratio (10g / L~200g / L) is suitable for batch processing needs in industrial production, avoiding incomplete reaction due to an excessively high solid-liquid ratio or increased equipment energy consumption due to an excessively low solid-liquid ratio. Optionally, the solid-liquid ratio between the first leaching residue and the sulfuric acid solution can be 10g / L, 50g / L, 100g / L, 150g / L, or 200g / L; preferably, the solid-liquid ratio between the first leaching residue and the sulfuric acid solution is 100g / L, which is suitable for the capacity of conventional industrial reactors, balancing batch processing and reaction adequacy, and resulting in low energy consumption.

[0060] The leaching temperature (25℃~80℃) controls the reaction rate between sulfuric acid and Li₂O and La₂O₃ in LLZO. As the leaching temperature increases, the reaction rate accelerates. Temperatures above 25℃ ensure leaching efficiency and production pace, while temperatures below 80℃ help control equipment costs and process stability. Optionally, the leaching temperature of the first leaching residue can be 25℃, 40℃, 55℃, 70℃, or 80℃; preferably, the leaching temperature of the first leaching residue is 55℃, which ensures efficient leaching of Li and La while also considering process stability and industrial equipment costs.

[0061] In some specific embodiments, the pH of the first mixture is adjusted to 10-12 and heated to 80-100°C, then sodium carbonate or carbon dioxide is added to react and obtain lithium carbonate precipitate. The combination of an alkaline environment and heating creates favorable conditions for lithium carbonate precipitation; the strong alkalinity of pH 10-12 inhibits Li... + Hydrolysis promotes CO3 2- With Li + The reaction produces sparingly soluble lithium carbonate. A temperature of 80℃~100℃ increases the reaction rate, shortens the precipitation time, and ensures more complete lithium carbonate crystallization, facilitating subsequent filtration and separation. Under these pH and temperature conditions, the lithium precipitation rate is ≥95%, solving the problem of low lithium recovery rates in traditional processes. Furthermore, in a strongly alkaline environment of pH 10~12, residual trace impurities are first removed by forming hydroxide precipitates, preventing them from contaminating the lithium carbonate product. Heating below 100℃ prevents the decomposition of sodium carbonate, ensuring reaction stability. The final lithium carbonate purity is ≥99.5%, meeting battery-grade standards.

[0062] Optionally, the pH of the first mixture is adjusted to 10 and heated to 100°C, or the pH of the first mixture is adjusted to 11 and heated to 90°C, or the pH of the first mixture is adjusted to 12 and heated to 80°C; preferably, the pH of the first mixture is adjusted to 11 and heated to 90°C. This method has good process parameter synergy, leaves sufficient safety margins, avoids frequent adjustments, and finally yields large lithium carbonate precipitate particles that are easy to filter and separate, and have low water content.

[0063] S5. The second leaching residue is leached with hydrofluoric acid solution to separate a third leaching solution and a carbon-containing third leaching residue; oxalic acid or oxalate is added to the third leaching solution to separate zirconium oxalate precipitate and a second mixed solution containing fluorine silicon; the second mixed solution is concentrated to obtain fluorosilicic acid.

[0064] The second leaching residue was treated with hydrofluoric acid solution, and the H+ of the hydrofluoric acid... + First, erode and activate ZrO2 and silicon-carbon, then use hydrofluoric acid. - With Zr 4+ Si 4+ Formation of stable complex ions (ZrF6) 2- SiF6 2- This process dissolves ZrO2 and SiO2 to generate a third leaching solution. Carbon (mainly a mixture of conductive carbon and graphite) and residual binder are insoluble in HF, leaving behind the third leaching residue, thus achieving the final separation of (Zr, Si) and carbon. For the third leaching solution, ZrF6 is used... 2- With C2O4 2- The characteristic of generating sparingly soluble zirconium oxalate allows for the separation of Zr, followed by concentration of the fluorosilicic acid-containing mixture to obtain fluorosilicic acid. This achieves full component recovery, recovering Zr (zirconium oxalate) from LLZO, Si (fluorosilicic acid) from silicon-carbon, and carbon, while eliminating resource waste.

[0065] In some specific embodiments, the mass concentration of the hydrofluoric acid solution ranges from 10% to 30%, and the leaching temperature of the second leaching residue ranges from 60°C to 80°C. If the concentration of the hydrofluoric acid solution is too low, ZrO2 and SiO2 will not dissolve sufficiently; if the concentration is too high, the hydrofluoric acid will be too corrosive, increasing equipment protection costs (requiring corrosion-resistant materials). This concentration range (10% to 30%) can achieve a Zr and Si leaching rate of ≥95%. Under leaching temperature conditions (60°C to 80°C), the second leaching residue can effectively improve the fluorine content of Zr and Si. - With (Zr) 4+ Si 4+ The complexation reaction rate of hydrofluoric acid is reduced, the leaching time is shortened, and the volatilization of hydrofluoric acid caused by high temperature is avoided (hydrofluoric acid has a boiling point of 19.5℃, but volatilization can be controlled by sealing equipment at 60~80℃).

[0066] Optionally, the mass concentration of the hydrofluoric acid solution can be 10%, 15%, 20%, 25%, or 30%; preferably, the mass concentration of the hydrofluoric acid solution is 20%, balancing leaching efficiency and cost.

[0067] Optionally, the leaching temperature of the second leaching residue can be 60°C, 65°C, 70°C, 75°C, or 80°C; preferably, the leaching temperature of the second leaching residue is 70°C, which has high leaching efficiency and also reduces the risk of hydrofluoric acid volatilization.

[0068] In some specific embodiments, the second mixture is concentrated at 60°C to 80°C. At 60°C to 80°C, the water in the second mixture can be rapidly evaporated, increasing the fluorosilicic acid concentration to industrial-grade standards (≥20%). Simultaneously, excessively high temperatures (>80°C) prevent the decomposition of fluorosilicic acid, ensuring a silicon resource recovery rate of ≥95%, converting silicon into high-value industrial raw materials, and improving the economic feasibility of industrialization. Furthermore, excessively low temperatures (<60°C) also prevent low concentration efficiency and extended production cycles.

[0069] Optionally, the second mixture can be concentrated at 60°C, 65°C, 70°C, 75°C, or 80°C; preferably, the second mixture is concentrated at 70°C, which is consistent with the preferred leaching temperature of the second leaching residue, allowing for the sharing of heating equipment and reducing energy consumption; at 70°C, the decomposition rate of fluorosilicic acid is <1%, and the concentration reaches the standard quickly.

[0070] The method for recycling solid-state battery materials of the present invention: First, a first mixed powder is recovered from the solid-state battery. The powdered recovered material has effectively broken down the components, so that the target components are fully exposed in particulate form, which facilitates subsequent heating, leaching, separation and other steps, and lays the foundation for efficient recovery. Next, heating in an air atmosphere can effectively weaken the adhesion of residual binders in lithium lanthanum zirconium oxide solid electrolyte, nickel cobalt manganese lithium ternary cathode material, and silicon-carbon anode material, which is beneficial to improving subsequent leaching efficiency; it can also slightly oxidize the elemental silicon in silicon-carbon anode material (generating SiO2, which is easier to process later); and it can also relax the crystal structure of nickel cobalt manganese lithium ternary cathode material and lithium lanthanum zirconium oxide solid electrolyte, reducing the subsequent acid dissolution activation energy. Next, given the difference in solubility of lithium lanthanum zirconium oxide solid electrolyte and nickel-cobalt-manganese lithium ternary cathode material in weak organic acids, the core valuable metals (lithium, nickel, cobalt, and manganese) and metal impurities (copper and aluminum) in the nickel-cobalt-manganese lithium ternary cathode material are preferentially leached out through the combined action of the weak organic acid solution and the reducing agent to form the first leachate. Lithium carbonate, nickel compounds, cobalt compounds, and manganese compounds are then extracted from this leachate through a wet process, while copper and aluminum impurities are removed during the wet process. The lithium lanthanum zirconium oxide solid electrolyte (resistant to weak organic acids) and silicon-carbon anode material (poorly soluble in weak organic acids) remain as the first leachate residue. This achieves precise separation of the lithium lanthanum zirconium oxide solid electrolyte and the nickel-cobalt-manganese lithium ternary cathode material, providing a high-purity leachate for the extraction of battery-grade compounds through wet processes (extraction, crystallization, etc.), ensuring the purity of subsequent products, and solving the problem of metal cross-contamination in traditional processes. Then, the crystal structure of the lithium lanthanum zirconium oxide solid electrolyte in the first leaching residue is destroyed by sulfuric acid solution (strong acid), dissolving Li2O and La2O3 (generating Li2SO4 and La2(SO4)3) to form the second leaching solution. ZrO2 in the lithium lanthanum zirconium oxide solid electrolyte and the silicon-carbon anode material are poorly soluble in sulfuric acid solution and remain as the second leaching residue. This achieves a secondary separation of (Li, La) and (Zr, silicon-carbon), which not only facilitates the efficient recovery of high-value La (lanthanum oxalate) and Li (lithium carbonate) from LLZO, avoiding the waste of valuable metals in LLZO, but also paves the way for subsequent Zr and carbon recovery, further improving resource utilization. For the second leaching solution, La is first utilized... 3+ With C2O4 2- The property of generating sparingly soluble lanthanum oxalate allows for precise separation of La. Then, by adjusting the pH to alkaline, the common ion effect (sodium carbonate / CO2) is utilized to separate Li. + Precipitation in the form of lithium carbonate enables precise separation of La and Li; Finally, the second leaching residue was treated with hydrofluoric acid solution, and the H+ of the hydrofluoric acid was reduced. + First, erode and activate ZrO2 and silicon-carbon, then use hydrofluoric acid. - With Zr 4+ Si 4+ Formation of stable complex ions (ZrF6) 2- SiF6 2- This process dissolves ZrO2 and SiO2 to generate a third leaching solution. Carbon (mainly a mixture of conductive carbon and graphite) and residual binder are insoluble in HF, leaving behind the third leaching residue, thus achieving the final separation of (Zr, Si) and carbon. For the third leaching solution, ZrF6 is used... 2- With C2O4 2- The characteristic of generating sparingly soluble zirconium oxalate allows for the separation of Zr, followed by concentration of the fluorosilicic acid-containing mixture to obtain fluorosilicic acid. This achieves full component recovery, recovering Zr (zirconium oxalate) from LLZO, Si (fluorosilicic acid) from silicon-carbon, and carbon, while eliminating resource waste.

[0071] In summary, this invention uses a powdered recycled material—a first mixed powder—containing lithium lanthanum zirconium oxide solid electrolyte, nickel-cobalt-manganese-lithium ternary cathode material, silicon-carbon anode material, and copper and aluminum impurities as a base. The process involves sequentially heating the powder in air, leaching with organic weak acids and reducing agents, sulfuric acid leaching, and hydrofluoric acid leaching, combined with wet processing and precipitation separation. This efficiently separates and recovers various valuable metals and silicon-carbon, while also removing copper and aluminum impurities. This not only effectively improves resource utilization but also significantly enhances the feasibility of industrialization.

[0072] Furthermore, the solid-state battery material recycling method of the present invention is compatible with existing lithium battery recycling processes. This means that the method is highly compatible with the traditional lithium battery recycling system in terms of process equipment, process framework, reagent system and product route. It does not require large-scale construction of new production lines or complete transformation of existing facilities, which can significantly reduce the threshold and cost of solid-state battery recycling industrialization, while realizing the integrated layout of "traditional lithium battery + solid-state lithium battery" recycling.

[0073] Example 1 Step S1: Preparation of the first mixed powder Discarded LLZO solid-state batteries (electrolyte is lithium lanthanum zirconium oxide, positive electrode is nickel cobalt manganese lithium ternary material, negative electrode is silicon carbon negative electrode material) were selected, first discharged to 0V, then crushed to particle size ≤5cm by jaw crusher, dried at 120℃ for 6h, and then ground to particle size ≤100μm by planetary ball mill. Finally, impurities such as plastic separator, metal foil, and shell were removed by sorting to obtain the first mixed powder, whose main components are LLZO electrolyte, nickel cobalt manganese lithium ternary material, silicon carbon and trace copper and aluminum impurities.

[0074] Step S2: Air Atmosphere Heating Treatment 100g of the first mixed powder was placed in a muffle furnace and heated at 150°C in air for 3 hours. After natural cooling, the second mixed powder was obtained. At this time, the adhesion of the binder was significantly weakened, the elemental silicon in silicon carbon was slightly oxidized to SiO2, and the crystal structure of the nickel-cobalt-manganese-lithium ternary cathode material and the lithium lanthanum-zirconium oxide solid electrolyte was relaxed.

[0075] Step S3: Organic weak acid + reducing agent leaching and wet extraction process (1) Prepare a 2 mol / L oxalic acid-citric acid mixed solution (oxalic acid:citric acid = 1:1, mass ratio) as an organic weak acid solution, and add 1 mol / L hydrogen peroxide (30 wt%) as a reducing agent. Add the second mixed powder to the above solution at a solid-liquid ratio of 100 g / L, stir and leach at 45°C for 3 h, and filter to obtain the first leaching residue (mainly LLZO and silicon carbide) and the first leaching solution (containing Li, Ni, Co, Mn, Cu, and Al).

[0076] (2) Wet extraction process A. Add 20% volume concentration of P2O4 to the first leachate and extract under the conditions of 30℃ and O / A=1:1 to separate the first extract containing Mn, Cu and Al and the first raffinate containing Li, Ni and Co. B. Add 2 mol / L sulfuric acid solution to the first extract and back-extract to obtain manganese sulfate solution. Evaporate and crystallize at 80℃ to obtain battery-grade manganese sulfate (purity ≥99.9%). C. The first raffinate was subjected to two fractional extractions using P507 with a volume concentration of 30%: the first extraction was performed by adjusting the pH to 3.5 and the O / A ratio to 1:1 to obtain a second extract containing Co; the second extraction was performed by adjusting the pH to 5.0 and the O / A ratio to 3:1 to obtain a third extract containing Ni, and the remaining aqueous phase was the second raffinate containing Li. D. The second and third extracts were back-extracted with 2 mol / L sulfuric acid solution to obtain cobalt sulfate solution and crude nickel sulfate solution; 10% C272 was added to the crude nickel sulfate solution for purification to obtain purified nickel sulfate solution. E. Cobalt sulfate solution and nickel sulfate solution are evaporated and crystallized at 80℃ to obtain battery-grade cobalt sulfate (purity ≥99.9%) and battery-grade nickel sulfate (purity ≥99.9%). F. Adjust the pH of the second raffinate to 11 with sodium hydroxide, heat to 90°C, introduce carbon dioxide to react, and filter to obtain battery-grade lithium carbonate (purity ≥ 99.5%).

[0077] Step S4: Sulfuric acid leaching and lanthanum and lithium recovery (1) Prepare a 3 mol / L sulfuric acid solution, add the first leaching residue at a solid-liquid ratio of 100 g / L, stir and leach at 55 °C for 4 h, and filter to obtain the second leaching residue (mainly ZrO2 and silicon carbide) and the second leaching solution (containing Li and La). (2) Add saturated oxalic acid solution to the second leachate, stir to generate lanthanum oxalate precipitate, filter and wash to obtain lanthanum oxalate product (purity ≥99%). (3) Adjust the pH of the first mixture after lanthanum precipitation to 11 with sodium hydroxide, heat to 90°C, add sodium carbonate solution to react, and filter to obtain battery-grade lithium carbonate (purity ≥ 99.5%).

[0078] Step S5: Hydrofluoric acid leaching and recovery of zirconium, silicon, and carbon (1) Prepare a 20% mass concentration hydrofluoric acid solution, add the second leaching residue, seal and stir at 70°C for 6 hours, filter to obtain the third leaching residue (containing carbon) and the third leaching solution (containing Zr and Si). (2) Add saturated oxalic acid solution to the third leachate to generate zirconium oxalate precipitate. After filtration and washing, zirconium oxalate product (purity ≥98%) is obtained. (3) The second mixture after zirconium precipitation is concentrated under reduced pressure at 70°C to obtain industrial grade fluorosilicic acid (concentration ≥20%); the third leaching residue is dried to obtain recovered carbon powder (purity ≥95%).

[0079] Example 2 Steps S1-S3 Similar to Example 1, except that the heating conditions for the first mixed powder were changed to heating at 200°C in an air atmosphere for 1 hour.

[0080] Step S3 The organic weak acid solution was replaced with a 1 mol / L citric acid solution, the reducing agent was 50 g / L sodium sulfite (solid), the solid-liquid ratio was 50 g / L, the leaching temperature was 60℃, and the leaching time was 2 h. The wet process parameters were the same as in Example 1, and the purity of the battery-grade manganese sulfate, cobalt sulfate, nickel sulfate, and lithium carbonate obtained was comparable to that in Example 1.

[0081] Step S4 The sulfuric acid solution concentration was changed to 5 mol / L, the solid-liquid ratio was 50 g / L, the leaching temperature was 80℃, and the leaching time was 2 h. The parameters for lanthanum precipitation and lithium precipitation were the same as in Example 1, and the recovery rates of lanthanum oxalate and lithium carbonate were 98% and 95%, respectively.

[0082] Step S5 The concentration of hydrofluoric acid solution was changed to 30% by mass, the leaching temperature was 80℃, and the leaching time was 4h. The zirconium precipitation and concentration parameters were the same as in Example 1, with zirconium oxalate purity ≥98%, fluorosilicic acid concentration ≥20%, and toner recovery rate ≥90%.

[0083] Example 3 Steps S1-S2 Similar to Example 1, except that the heating conditions for the first mixed powder were changed to heating at 100°C in an air atmosphere for 5 hours.

[0084] Step S3 The organic weak acid solution was replaced with a 4 mol / L acetic acid solution, the reducing agent was 0.5 mol / L hydrogen peroxide, the solid-liquid ratio was 200 g / L, the leaching temperature was 25℃, and the leaching time was 8 h. In the wet process, the volume concentration of P2O4 was changed to 30%, and the volume concentration of P5O7 was changed to 45%. The purity of the final battery-grade product was slightly lower than that of Example 1 (purity of manganese sulfate / cobalt / nickel ≥99.5%, and purity of lithium carbonate ≥99%).

[0085] Step S4 The sulfuric acid solution concentration was changed to 1 mol / L, the solid-liquid ratio was 200 g / L, the leaching temperature was 25℃, and the leaching time was 8 h. The parameters for lanthanum precipitation and lithium precipitation were the same as in Example 1, and the recovery rates of lanthanum oxalate and lithium carbonate were 90% and 92%, respectively.

[0086] Step S5 The hydrofluoric acid solution concentration was changed to 10% by mass, the leaching temperature was 60℃, and the leaching time was 8h; after zirconium precipitation, the zirconium oxalate purity was ≥97%, the fluorosilicic acid concentration was ≥18%, and the carbon powder recovery rate was ≥92%.

[0087] Example Results Explanation In Examples 1-3, Example 1 uses the optimal parameters, with the recovery rates of each valuable metal being: Ni, Co, Mn ≥ 98%, Li ≥ 95%, La ≥ 98%, Zr ≥ 95%, Si ≥ 95%, and carbon powder recovery rate ≥ 95%. In Examples 2 and 3, the recovery rates decreased slightly due to parameter adjustments, but both still met the requirements for industrial production, and the purity of all products met industrial or battery-grade standards.

[0088] The above provides a detailed description of a method for recycling solid-state battery materials according to embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method of recycling a solid-state battery material, characterized by, The method comprises the following steps: S1, recovering a first mixed powder from a solid-state battery, wherein the first mixed powder comprises lithium lanthanum zirconium oxide solid-state electrolyte, nickel cobalt manganese lithium ternary positive electrode material, silicon carbon negative electrode material and copper aluminum impurities; S2, heating and treating the first mixed powder in an air atmosphere to obtain a second mixed powder; S3, leaching the second mixed powder with an organic weak acid solution and a reducing agent to separate a first leaching residue and a first leaching solution containing lithium, nickel, cobalt, manganese, copper and aluminum, and then extracting lithium carbonate, nickel compounds, cobalt compounds and manganese compounds from the first leaching solution through a wet process; S4, leaching the first leaching residue with a sulfuric acid solution to separate a second leaching residue and a second leaching solution containing lithium and lanthanum; adding oxalic acid or oxalate to the second leaching solution to separate lanthanum oxalate precipitate and a first mixed solution containing lithium; adjusting the pH of the first mixed solution to be alkaline and adding sodium carbonate or carbon dioxide to react to obtain lithium carbonate precipitate; S5, leaching the second leaching residue with a hydrofluoric acid solution to separate a third leaching solution and a third leaching residue containing carbon; adding oxalic acid or oxalate to the third leaching solution to separate zirconium oxalate precipitate and a second mixed solution containing fluorosilicon, and the second mixed solution is concentrated to obtain fluorosilicic acid.

2. The method of recycling solid-state battery material of claim 1, wherein, The first mixed powder recovered from the solid-state battery comprises: The solid-state battery is sequentially subjected to discharge treatment, crushing treatment, drying treatment, grinding treatment and sorting treatment to obtain the first mixed powder.

3. The method of recycling solid-state battery material of claim 1, wherein, Step S2 comprises: The first mixed powder is heated and treated in an air atmosphere at 100-200℃ for 1-5h to obtain the second mixed powder.

4. The method of recycling solid-state battery material of claim 1, wherein, In step S3, the solute of the organic weak acid solution is one or more of oxalic acid, citric acid, formic acid, acetic acid and tartaric acid, the concentration of the organic weak acid solution is 0.5-4mol / L, and the solid-liquid ratio between the second mixed powder and the organic weak acid solution is 10-200g / L; The leaching temperature of the second mixed powder is 25-60℃.

5. The method of recycling solid-state battery material according to claim 1 or 4, wherein In step S3, the reducing agent is one or more of hydrogen peroxide, sodium sulfite and sodium bisulfite; The amount of the reducing agent is determined based on the volume of the organic weak acid solution as follows: The amount of the solid reducing agent is 1-200g / L, and the amount of the liquid reducing agent is 0.1-5mol / L.

6. The method of recycling solid-state battery material of claim 1, wherein, The extraction of lithium carbonate, nickel compounds, cobalt compounds and manganese compounds from the first leaching solution through a wet process comprises: S31, adding di(2-ethylhexyl)phosphate to the first leaching solution for extraction treatment to separate a first extraction solution containing manganese, copper and aluminum, and a first raffinate containing lithium, nickel and cobalt; S32, adding a sulfuric acid solution to the first extraction solution for back extraction treatment to separate a manganese sulfate solution; the manganese sulfate solution is subjected to evaporation and crystallization treatment to prepare a battery-grade manganese sulfate product. S33, the first raffinate is subjected to twice fractional extraction with 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester, and a second extraction liquid containing cobalt, a third extraction liquid containing nickel and a second raffinate containing lithium are separated; S34, the second extraction liquid and the third extraction liquid are subjected to stripping treatment with a sulfuric acid solution respectively, and a cobalt sulfate solution and a nickel sulfate crude solution are separated; S35, the nickel sulfate crude solution is subjected to impurity removal purification treatment with bis(2,4,4-trimethylpentyl) phosphonic acid, and a purified nickel sulfate solution is obtained; S36, the cobalt sulfate solution and the nickel sulfate solution are subjected to evaporation crystallization treatment respectively, and a battery-grade cobalt sulfate product and a battery-grade nickel sulfate product are prepared; S37, the pH of the second raffinate is adjusted to 10-12, the reaction temperature is controlled in the range of 80-100℃, sodium carbonate or carbon dioxide is added for reaction, and a lithium carbonate product is separated after the reaction is completed.

7. The method of recycling solid-state battery material of claim 1, wherein, In step S4, the concentration of the sulfuric acid solution is in the range of 1-5 mol / L, the solid-liquid ratio between the first leaching residue and the sulfuric acid solution is 10-200 g / L, and the leaching temperature of the first leaching residue is in the range of 25-80℃.

8. The method of recycling solid-state battery material of claim 1, wherein, In step S4, the pH of the first mixed solution is adjusted to 10-12 and heated to 80-100℃, sodium carbonate or carbon dioxide is added for reaction, and a lithium carbonate precipitate is obtained.

9. The method of recycling solid-state battery material of claim 1, wherein, In step S5, the mass concentration of the hydrofluoric acid solution is in the range of 10-30%, and the leaching temperature of the second leaching residue is in the range of 60-80℃.

10. The method of recycling solid-state battery material of claim 1, wherein, In step S5, the second mixed solution is concentrated at 60-80℃.

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