A method for recovering lithium resources

Abstract

The present application provides a lithium resource recovery method, comprising an anode, a cathode and an electrolyte solution forming an electrolytic cell, a step of lithium element leaching from the anode by electrode plate oxidation driven by an electric field and in-situ electrolyte oxidation driven by electrocatalysis, and the anode is prepared by using lithium resources. The recovery method of the present application can use various lithium resources to prepare the anode to form the electrolytic cell, and when the electrolytic cell works, the anode couples the double oxidation mechanism to various lithium resources by the electrode plate oxidation mechanism driven by the electric field and the in-situ electrolyte oxidation mechanism driven by the electrocatalysis, thereby promoting the high selectivity leaching of lithium metal from the lattice of the anode material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium resource recycling, and particularly relates to a lithium resource recycling method. BACKGROUND

[0002] Lithium metal plays an irreplaceable role in emerging industries such as new materials, new energy, information technology, aerospace, and national defense and military industry. In recent years, with the rapid development of the new energy vehicle industry, the application demand of power batteries and energy storage batteries relying on lithium metal supply has shown explosive growth, which has also brought huge market demand for lithium metal resources in the energy storage industry chain.

[0003] In the related art, the recycling technology of lithium metal is backward. The main way to obtain lithium metal is to rely on the mining of lithium-rich ore natural resources or to recycle lithium metal from retired lithium-ion batteries for reuse. At present, the methods for obtaining lithium resources by these two ways mainly focus on pyrometallurgy and hydrometallurgy. The hydrometallurgical process uses a large amount of strong acid as a leaching agent, and uses hydrogen peroxide reagent with high risk as a reducing agent, which non-selectively leaches all metals in the retired battery cathode material and lithium ore and various lithium resources to obtain a leaching solution mixed with lithium and other metal elements, and cannot selectively recover lithium metal. The subsequent process separates various metals through extraction, precipitation and other technologies, and the process is complicated. The pyrometallurgical process usually processes retired battery cathode materials and lithium ore and various lithium resources at a high temperature of more than 800℃, and is often combined with the hydrometallurgical process after roasting to further leach lithium and other valuable metals in the powder, which has problems of low selectivity of leaching lithium, low lithium recovery rate, high energy consumption, and high pollution.

[0004] The prior art cannot achieve high selectivity leaching and recovery of lithium from retired batteries, lithium ore and various lithium resources, and the process is often accompanied by problems of use of high-risk chemical reagents, high energy consumption, high pollution and the like. Therefore, it is necessary to develop a method with high lithium selective extraction rate, simple process, low energy consumption and low environmental risk, so as to reduce the cost of lithium resource mining and recovery and alleviate the contradiction between supply and demand of lithium resources. SUMMARY

[0005] The present application aims to at least solve one of the above technical problems in the prior art. To this end, the present application provides a lithium resource recycling method, which can use various lithium resources to prepare an anode (working electrode) to form an electrolytic cell. When the electrolytic cell works, the anode is coupled with an in-situ oxidation mechanism of an electrolyte driven by electrocatalysis through an electrode plate oxidation mechanism driven by an electric field, so as to couple the double oxidation mechanisms to various lithium resources, and promote the high selectivity leaching of lithium metal from the lattice of the anode material. After leaching, a lithium-rich electrolyte is obtained, and products such as lithium carbonate can be obtained by a precipitation method. The electrolyte after precipitation can be recycled for use in the electrolytic cell.

[0006] The first aspect of the present application provides a lithium resource recovery method, comprising an anode, a cathode and an electrolyte solution forming an electrolytic cell, a step of leaching lithium from the anode by electrode plate oxidation driven by an electric field and in-situ electrolyte oxidation driven by electrocatalysis, and the anode is prepared from lithium resources.

[0007] The present application relates to a technical solution in the lithium resource recovery method, at least has the following beneficial effects:

[0008] The lithium resource recovery method of the present application can use various lithium resources to prepare an anode (working electrode) to form an electrolytic cell. During operation of the electrolytic cell, the anode is coupled with in-situ electrolyte oxidation mechanism driven by electrocatalysis through electrode plate oxidation mechanism driven by an electric field, thereby coupling double oxidation mechanisms to various lithium resources, and promoting high selectivity leaching of lithium metal from the lattice of the anode material. After leaching, the obtained lithium-rich electrolyte can be precipitated to obtain products such as lithium carbonate, and the precipitated electrolyte can be recycled for electrolytic cell operation.

[0009] The lithium resource recovery method of the present application can use various lithium resources to prepare an anode (working electrode), use a titanium plate as a current collector to represent a cathode (counter electrode), use various salt solutions as oxidation electrolyte, and use photovoltaic solar panels and storage batteries to generate and store electricity as an energy supply system, thereby forming a closed-loop electro-oxidation process. During operation of the electrolytic cell, the anode is coupled with in-situ electrolyte oxidation mechanism driven by electrocatalysis through electrode plate oxidation mechanism driven by an electric field, thereby coupling double oxidation mechanisms to various lithium resources, and promoting high selectivity leaching of lithium metal from the lattice of the anode material. After leaching, the obtained lithium-rich electrolyte can be precipitated to obtain products such as lithium carbonate, and the precipitated electrolyte can be recycled for electrolytic cell operation.

[0010] The in-situ electrolyte oxidation mechanism driven by electrocatalysis produces active species, wherein the "active species" refers to chemical species with oxidation ability. Taking NaCl solution as an example, the chemical species with oxidation ability include chlorine radicals, chlorine gas, etc. Other iodine solutions and sulfate solutions also have iodine radicals and sulfate radicals. For NaCl solution, the "active species" includes HClO, Cl2, and ClO·.

[0011] The lithium resource recovery method of the present application can effectively leach lithium metal in various configurations without being limited by the morphology and structure of the electrolytic cell.

[0012] The lithium resource recovery method of the present application has a shorter lithium extraction time (for retired batteries, the reaction is basically in equilibrium within 40 minutes, and the present application can achieve a higher recovery rate within 90 minutes), faster reaction kinetics, and stronger production capacity per unit time after equipment.

[0013] The lithium resource recovery method has the advantages of green and environmental protection, low carbon footprint, no use of any toxic and harmful chemical reagents in the whole process of lithium leaching, and selective lithium extraction by using electrically driven oxidation.

[0014] The lithium resource recovery method has the advantages of high selectivity of lithium extraction, no destruction of the framework structure of the material, extraction of lithium in the material lattice, mild lithium extraction reaction, no leaching of other transition metals such as Ni, Co and Mn, and high selectivity of lithium leaching. The processes such as fire method and wet method cannot selectively leach lithium metal, and can only leach all metals and then recover various metals in sequence.

[0015] Since the lithium leaching is from the lattice of the material, there is an ion channel. Nickel, cobalt and manganese are the skeleton of the material, and the intermolecular force is stronger. The uniqueness of lithium leaching is the same as the charging and discharging of the battery. The double oxidation of the application is mainly electrode oxidation, supplemented by chemical oxidant, and the generated active oxidant is more mild compared with strong acid leaching. Therefore, the application mainly aims at lithium leaching, rather than nickel, cobalt and manganese leaching.

[0016] The lithium resource recovery method has the advantages of green and environmental protection, low carbon footprint, no use of any toxic and harmful chemical reagents in the whole process of lithium leaching, and selective lithium extraction by using electrically driven oxidation.

[0017] According to some embodiments of the application, the electrolyte solution is a salt solution capable of forming active species with oxidation ability under anode oxidation.

[0018] According to some embodiments of the application, the salt solution includes at least one of a chloride salt solution, a bromide salt solution, an iodide salt solution and a sulfate salt solution.

[0019] According to some embodiments of the application, the lithium resource includes at least one of retired lithium ion battery positive electrode powder and lithium ore powder.

[0020] According to some embodiments of the application, the method further includes the step of applying the slurry containing the lithium resource on the current collector to obtain the anode.

[0021] According to some embodiments of the application, the current collector includes at least one of a titanium plate current collector, a carbon cloth current collector, a steel plate current collector and an iron plate current collector.

[0022] According to some embodiments of the application, the method further includes the step of adding a precipitating agent to the lithium-containing electrolyte to obtain a lithium-containing precipitate.

[0023] According to some embodiments of the present application, the lithium-containing precipitate comprises lithium carbonate, lithium phosphate and lithium oxalate.

[0024] According to some embodiments of the present application, the working voltage of the electrolysis process is ≤36V.

[0025] According to some embodiments of the present application, the working time of the electrolysis process is ≤120min.

[0026] The working voltage and working time of the electrolysis process refer to the voltage and time of the electric field-driven electrode plate oxidation and the in-situ electrolyte oxidation driven by electrocatalysis.

[0027] According to some embodiments of the present application, the method comprises the following steps:

[0028] S1: applying a slurry containing the lithium resource on a current collector to obtain the anode;

[0029] S2: selecting a cathode, an oxidizing electrolyte and an energy supply system to construct an electrolytic cell with the anode;

[0030] S3: performing the electric field-driven electrode plate oxidation and in-situ electrolyte oxidation driven by electrocatalysis under power supply conditions to drive lithium leaching, to obtain a lithium-containing electrolyte;

[0031] S4: filtering the impurities in the lithium-containing electrolyte to obtain supernatant, and adding a precipitating agent to the supernatant to obtain a lithium-containing precipitate.

[0032] According to some embodiments of the present application, in step S1, the preparation method of the slurry containing the lithium resource comprises the following steps: pretreating the lithium resource to obtain a lithium-containing powder, mixing the lithium-containing powder with a binder and a solvent to obtain the slurry.

[0033] According to some embodiments of the present application, the pretreatment comprises drying, crushing and sieving the lithium resource to obtain a powder containing lithium metal.

[0034] According to some embodiments of the present application, the particle size of the powder containing lithium metal is less than 1mm.

[0035] According to some embodiments of the present application, the binder comprises polyvinylidene fluoride (PVDF).

[0036] According to some embodiments of the present application, the solvent comprises N-methyl pyrrolidone (NMP).

[0037] In the slurry, the mass ratio of the powder containing lithium metal, the binder and the solvent is 20:0-2:5-10.

[0038] According to some embodiments of the present application, the lithium resource comprises at least one of retired lithium-ion battery cathode powder and lithium ore powder.

[0039] According to some embodiments of the present application, the retired lithium-ion battery cathode powder comprises at least one of lithium iron phosphate battery (LiFeP04) powder, lithium cobalt oxide battery (LiCo02) powder, lithium manganate battery (LiMn204) powder, lithium nickel cobalt manganese ternary battery (Li(Ni x Co y Mn z )02) powder.

[0040] According to some embodiments of the present application, the lithium ore powder comprises at least one of spodumene, lepidolite.

[0041] According to some embodiments of the present application, the current collector comprises a mature industrial product that can be obtained on a large scale.

[0042] According to some embodiments of the present application, the current collector comprises at least one of titanium plate current collector, carbon cloth current collector, steel plate current collector, and iron plate current collector.

[0043] The current collector can be any conductive material other than those listed above.

[0044] According to some embodiments of the present application, the anode current collector comprises at least one of titanium plate current collector, carbon cloth current collector, steel plate current collector, and iron plate current collector.

[0045] According to some embodiments of the present application, the cathode current collector comprises at least one of titanium plate current collector, carbon cloth current collector, steel plate current collector, and iron plate current collector.

[0046] In addition to the above materials, the current collector can also be replaced by other corrosion-resistant materials with good electrical conductivity.

[0047] According to some embodiments of the present application, in step S1, the slurry containing the lithium resource is coated on the current collector, and after drying, the anode is obtained.

[0048] The drying temperature can be about 20-80°C.

[0049] According to some embodiments of the present application, the oxidation electrolyte comprises at least one of chloride salt electrolyte, bromide salt electrolyte, iodide salt electrolyte, and sulfate salt electrolyte.

[0050] According to some embodiments of the present application, the chloride salt electrolyte comprises sodium chloride, natural seawater electrolyte.

[0051] When the electrolyte is natural seawater electrolyte, KOH needs to be added to adjust the pH to precipitate calcium ions and magnesium ions.

[0052] According to some embodiments of the present application, the bromide salt electrolyte comprises a sodium bromide electrolyte.

[0053] According to some embodiments of the present application, the iodide salt electrolyte comprises a sodium iodide electrolyte.

[0054] According to some embodiments of the present application, the sulfate salt electrolyte comprises a sodium sulfate electrolyte.

[0055] According to some embodiments of the present application, the energy supply system comprises a combination of photovoltaic solar panels and a battery.

[0056] According to some embodiments of the present application, the photovoltaic solar panels comprise at least one of silicon-based solar cells, perovskite solar cells, thin-film solar cells, and organic solar cells.

[0057] According to some embodiments of the present application, the battery comprises at least one of lithium ion batteries and sodium ion batteries.

[0058] According to some embodiments of the present application, in step S2, the anode and cathode can be alternately arranged in the electrolytic cell to form a multi-channel parallel electrolysis system, which is further used for large-scale processing.

[0059] According to some embodiments of the present application, in step S3, the working voltage of the electrolysis process is ≤36V.

[0060] The above-mentioned voltage is only a preferred voltage, and does not mean that the voltage must be limited within the above-mentioned range.

[0061] According to some embodiments of the present application, in step S3, the working time of the electrolysis process is ≤120min.

[0062] The above-mentioned time is only a preferred time, and does not mean that the time must be limited within the above-mentioned range.

[0063] The electrolytic cell is driven by the electro-oxidation mechanism under stable voltage power supply conditions to carry out lithium leaching reaction, and after the reaction is completed, an electrolyte rich in lithium ions is obtained.

[0064] According to some embodiments of the present application, in step S3, the anode electrode plate is oxidized under the driving of the electric field, and at the same time, in-situ electrocatalytic oxidation of the anode occurs.

[0065] According to some embodiments of the present application, in step S3, the in-situ electrocatalytic oxidation of the electrolyte is ≤120min.

[0066] The above-mentioned time is only a preferred time, and does not mean that the time must be limited within the above-mentioned range.

[0067] According to some embodiments of the present application, in step S4, when the lithium-containing electrolyte uses seawater as the electrolyte, the pH of the electrolyte needs to be adjusted, so as to remove Ca 2+ , Mg 2+ ions in the seawater.

[0068] According to some embodiments of the present application, in step S4, the precipitant includes potassium carbonate, sodium carbonate, potassium phosphate, sodium phosphate, carbon dioxide, and oxalic acid.

[0069] According to some embodiments of the present application, in step S4, the precipitant includes an agent capable of forming a precipitate with lithium ions.

[0070] According to some embodiments of the present application, the lithium-containing precipitate includes lithium carbonate, lithium phosphate, and lithium oxalate.

[0071] According to some embodiments of the present application, in step S4, the method further includes a step of drying the lithium-containing precipitate.

[0072] According to some embodiments of the present application, the lithium-containing precipitate is dried at a temperature of about 100℃ for about 1h. BRIEF DESCRIPTION OF DRAWINGS

[0073] Figure 1 is an XRD spectrum of a Li2CO3 product recovered from a multi-channel scale-up process.

[0074] Figure 2 is an XRD spectrum of a Li3PO4 product recovered. DETAILED DESCRIPTION

[0075] The following are specific embodiments of the present application, and the technical solutions of the present application are further described in combination with the embodiments, but the present application is not limited to these embodiments.

[0076] The first aspect of the present application provides a lithium resource recovery method, including the steps of forming an electrolytic cell by an anode, a cathode, and an electrolyte solution, and driving lithium elements to be leached from the anode by electrode plate oxidation driven by an electric field and in-situ electrolyte oxidation driven by electrocatalysis, and the anode is prepared by using lithium resources.

[0077] It can be understood that the lithium resource recovery method can utilize various lithium resources to prepare an anode (working electrode) to form an electrolytic cell. When the electrolytic cell works, the anode is coupled with an in-situ electrolyte oxidation mechanism driven by electrocatalysis through an electrode plate oxidation mechanism driven by an electric field, so as to couple the double oxidation mechanisms to various lithium resources, and promote the high selectivity leaching of lithium metal from the lattice of the anode material. After leaching, the obtained lithium-rich electrolyte can be used to obtain products such as lithium carbonate by a precipitation method, and the electrolyte after precipitation can be recycled for electrolytic cell work.

[0078] The lithium resource recovery method can utilize various lithium resources to prepare an anode (working electrode) to form an electrolytic cell. When the electrolytic cell works, the anode is coupled with an in-situ electrolyte oxidation mechanism driven by electrocatalysis through an electrode plate oxidation mechanism driven by an electric field, so as to couple the double oxidation mechanisms to various lithium resources, and promote the high selectivity leaching of lithium metal from the lattice of the anode material. After leaching, the obtained lithium-rich electrolyte can be used to obtain products such as lithium carbonate by a precipitation method, and the electrolyte after precipitation can be recycled for electrolytic cell work.

[0079] It should be noted that the in-situ electrolyte oxidation mechanism driven by electrocatalysis produces active species, wherein the "active species" refers to chemical species with oxidation ability. For example, the NaCl solution includes chemical species with oxidation ability such as chlorine radicals, chlorine gas, and the like. Other iodine solutions and sulfate solutions also include iodine radicals, sulfate radicals, and the like. For the NaCl solution, the "active species" includes HClO, Cl2, and ClO·.

[0080] The lithium resource recovery method can effectively leach lithium metal in various configurations without being limited by the morphology and structure of the electrolytic cell.

[0081] The lithium resource recovery method has a shorter lithium extraction time (for retired batteries, the reaction is basically in equilibrium within 40 minutes, and the recovery rate of the present application is higher within 90 minutes), faster reaction kinetics, and stronger production capacity per unit time after equipment.

[0082] The lithium resource recovery method is green and low-carbon throughout the process. In the lithium leaching process, no toxic and harmful chemical reagents are used throughout the process, and lithium can be selectively extracted by electrically driven oxidation. In addition, the recovery method of the present application can also use a photovoltaic power generation system for power supply throughout the process, which can make early layout for future green and intelligent recycling park construction.

[0083] The lithium resource recovery method can selectively extract lithium. The lithium extraction process does not destroy the framework structure of the material, but only extracts lithium from the material lattice, and the lithium extraction reaction is mild, and other transition metals such as Ni, Co and Mn are not leached out, and the method has the characteristics of high selectivity in leaching lithium. The fire method, wet method and the like cannot selectively leach lithium metal, and can only leach all metals, and then recover various metals in sequence.

[0084] It should be further pointed out that since the lithium leaching is from the lattice of the material, there is an ion channel. Nickel, cobalt and manganese are the skeleton of the material, and the intermolecular force is stronger. The uniqueness of lithium leaching is mainly the same as the charging and discharging of the battery. The double oxidation of the present application is mainly electrode oxidation, supplemented by chemical oxidizing agent, and compared with strong acid leaching, the generated active oxidizing agent is more mild, and therefore, the present application is mainly aimed at lithium leaching, but not nickel, cobalt and manganese leaching.

[0085] The lithium resource recovery method of the present application only needs the current collector to conduct electricity without other active material loading.

[0086] In some embodiments of the present application, the electrolyte solution is a salt solution capable of forming active species with oxidation ability under anode oxidation.

[0087] In some embodiments of the present application, the salt solution includes at least one of a chloride salt solution, a bromide salt solution, an iodide salt solution and a sulfate salt solution.

[0088] In some embodiments of the present application, the lithium resource includes at least one of retired lithium ion battery positive electrode powder and lithium ore powder.

[0089] In some embodiments of the present application, the method further includes the step of applying the slurry containing the lithium resource on the current collector to obtain the anode.

[0090] In some embodiments of the present application, the current collector includes at least one of a titanium plate current collector, a carbon cloth current collector, a steel plate current collector and an iron plate current collector.

[0091] In some embodiments of the present application, the method further includes the step of adding a precipitating agent to the lithium-containing electrolyte to obtain a lithium-containing precipitate after the lithium element is leached out.

[0092] In some embodiments of the present application, the lithium-containing precipitate includes lithium carbonate, lithium phosphate and lithium oxalate.

[0093] In some embodiments of the present application, the working voltage of the electrolysis process is ≤36V.

[0094] In some embodiments of the present application, the working time of the electrolysis process is ≤120min.

[0095] In some embodiments of the present application, the method specifically comprises the following steps:

[0096] S1: applying a slurry containing lithium resources on a current collector to obtain an anode;

[0097] S2: selecting a cathode, an oxidizing electrolyte and an energy supply system to construct an electrolytic cell with the anode;

[0098] S3: driving the electrode plate oxidation and in-situ electrocatalytic oxidation of the electrolyte under the power supply condition to drive the leaching of lithium, to obtain a lithium-containing electrolyte;

[0099] S4: obtaining a supernatant after filtering impurities in the lithium-containing electrolyte, and adding a precipitating agent to the supernatant to obtain a lithium-containing precipitate.

[0100] In some embodiments of the present application, in step S1, the preparation method of the slurry containing lithium resources comprises the following steps: pretreating the lithium resources to obtain a lithium-containing powder, mixing the lithium-containing powder with a binder and a solvent to obtain the slurry.

[0101] In some embodiments of the present application, the pretreatment comprises drying, crushing and sieving the lithium resources to obtain the lithium metal-containing powder.

[0102] In some embodiments of the present application, the particle size of the lithium metal-containing powder is less than 1 mm.

[0103] In some embodiments of the present application, the binder comprises polyvinylidene fluoride (PVDF).

[0104] In some embodiments of the present application, the solvent comprises N-methyl pyrrolidone (NMP).

[0105] In the slurry, the mass ratio of the lithium metal-containing powder, the binder and the solvent is 20:0-2:5-10.

[0106] In some embodiments of the present application, the lithium resources include at least one of retired lithium-ion battery positive electrode powder and lithium ore powder.

[0107] In some embodiments of the present application, the retired lithium-ion battery positive electrode powder includes at least one of lithium iron phosphate battery (LiFePO4) powder, lithium cobalt oxide battery (LiCoO2) powder, lithium manganate battery (LiMn2O4) powder, and nickel-cobalt-manganese ternary lithium battery (Li(Ni x Co y Mn z )O2) powder.

[0108] In some embodiments of the present application, the lithium ore powder includes at least one of spodumene and lepidolite.

[0109] In some embodiments of the present application, the current collector comprises a mature industrial product that can be obtained on a large scale.

[0110] In some embodiments of the present application, the current collector comprises at least one of a titanium plate current collector, a carbon cloth current collector, a steel plate current collector, and an iron plate current collector.

[0111] The current collector can be a current collector formed of any conductive material other than those listed above.

[0112] In some embodiments of the present application, the anode current collector comprises at least one of a titanium plate current collector, a carbon cloth current collector, a steel plate current collector, and an iron plate current collector.

[0113] In some embodiments of the present application, the cathode current collector comprises at least one of a titanium plate current collector, a carbon cloth current collector, a steel plate current collector, and an iron plate current collector.

[0114] In addition to the above materials, the current collector can also be replaced with other corrosion-resistant materials with good electrical conductivity.

[0115] In some embodiments of the present application, in step S1, the slurry containing lithium resources is coated on the current collector, and after drying, an anode is obtained.

[0116] The drying temperature can be about 20-80°C.

[0117] In some embodiments of the present application, the oxidation electrolyte comprises at least one of a chloride salt electrolyte, a bromide salt electrolyte, an iodide salt electrolyte, and a sulfate salt electrolyte.

[0118] In some embodiments of the present application, the chloride salt electrolyte comprises sodium chloride, natural seawater electrolyte.

[0119] When the electrolyte is a natural seawater electrolyte, KOH needs to be added to adjust the pH to precipitate calcium ions and magnesium ions.

[0120] In some embodiments of the present application, the bromide salt electrolyte comprises a sodium bromide electrolyte.

[0121] In some embodiments of the present application, the iodide salt electrolyte comprises a sodium iodide electrolyte.

[0122] In some embodiments of the present application, the sulfate salt electrolyte comprises a sodium sulfate electrolyte.

[0123] In some embodiments of the present application, the energy supply system comprises a combination of photovoltaic solar panels and storage batteries.

[0124] In some embodiments of the present application, the photovoltaic solar panels comprise at least one of silicon-based solar cells, perovskite solar cells, thin-film solar cells, and organic solar cells.

[0125] In some embodiments of the present application, the battery comprises at least one of a lithium ion battery and a sodium ion battery.

[0126] In some embodiments of the present application, in step S2, the anode and the cathode can be alternately arranged in the electrolytic cell to form a multi-channel parallel electrolysis system, which is further used for large-scale processing.

[0127] In some embodiments of the present application, in step S3, the voltage of the electric field driven electrode plate oxidation is ≤36V.

[0128] The above-mentioned voltage is only a preferred voltage, and does not mean that the voltage must be limited within the above-mentioned range.

[0129] In some embodiments of the present application, in step S3, the time of the electric field driven electrode plate oxidation is ≤120min.

[0130] The above-mentioned time is only a preferred time, and does not mean that the time must be limited within the above-mentioned range.

[0131] The electrolytic cell drives the lithium leaching reaction by the electric oxidation mechanism under the condition of stable voltage power supply, and obtains the electrolyte rich in lithium ions after the reaction is completed.

[0132] In some embodiments of the present application, in step S3, the anode electrode plate is oxidized by the electric field, and at the same time, the in-situ electrolytic oxidation of the anode is electrocatalyzed.

[0133] In some embodiments of the present application, in step S3, the voltage of the in-situ electrolytic oxidation of the electrolyte is ≤36V.

[0134] In some embodiments of the present application, in step S3, the time of the in-situ electrolytic oxidation of the electrolyte is ≤120min.

[0135] The above-mentioned time is only a preferred time, and does not mean that the time must be limited within the above-mentioned range.

[0136] In some embodiments of the present application, in step S4, when the lithium-containing electrolyte takes seawater as the electrolyte, the pH of the electrolyte needs to be adjusted, and the purpose is to remove Ca 2+ , Mg 2+ ions in seawater.

[0137] In some embodiments of the present application, in step S4, the precipitant comprises potassium carbonate, sodium carbonate, potassium phosphate, sodium phosphate, carbon dioxide, oxalic acid.

[0138] In some embodiments of the present application, in step S4, the precipitant comprises an agent capable of forming a precipitate with lithium ions.

[0139] In some embodiments of the present application, the lithium-containing precipitate comprises lithium carbonate, lithium phosphate and lithium oxalate.

[0140] In some embodiments of the present application, the step S4 further comprises a step of drying the lithium-containing precipitate.

[0141] In some embodiments of the present application, the lithium-containing precipitate is dried at a temperature of about 100°C for about 1 hour.

[0142] The technical solutions of the present application will be better understood in combination with the specific embodiments below.

[0143] It should be noted that all reagents in the embodiments are obtained from commercial channels.

[0144] The lithium resources in the embodiments are various retired lithium battery positive material powders or mineral powders that have been pretreated.

[0145] Embodiment 1

[0146] A retired lithium iron phosphate (LiFePO4) battery positive powder was used to prepare an anode with a size of 5 cm x 5 cm x 0.5 mm and connected to the positive pole of the power supply; a titanium plate was used as a cathode with a size of 5 cm x 5 cm x 0.5 mm and connected to the negative pole of the power supply; 8 pairs of electrode plates were used in parallel, the distance between the anode and the cathode plate was controlled to be 2 cm, 340 mL of 0.5 mol / L NaCl was used as the electrolyte, and an electrolytic cell was formed. After 90 minutes of reaction at a stable voltage of 2.5 V, a lithium-rich electrolyte was obtained. K2CO3 was added to the electrolyte to obtain a Li2CO3 precipitate, which was filtered and dried to obtain a Li2CO3 product. The Li2CO3 product was characterized by X-ray powder diffraction, and the results are shown in Figure 1 .

[0147] Table 1: Metal leaching rate of LiFePO4 in multi-channel large-scale treatment process

[0148]

[0149]

[0150] Table 2: Purity of recovered Li2CO3 in multi-channel large-scale treatment process

[0151] Element Li Fe Al K Other Content (%) 99.602 0.127 0.048 0.020 0.203

[0152] The purity of industrial-grade lithium carbonate is ≥99.5%. In this embodiment, the recovery rate is 99.6%, which already meets the demand for industrial-grade supply, so the precipitation process is not further optimized. The precipitation process can also be optimized according to actual needs to obtain lithium carbonate with higher purity.

[0153] Embodiment 2

[0154] An anode was prepared using retired lithium iron phosphate (LiFeP04) battery cathode powder, with a size of 5 cm x 5 cm x 0.5 mm, connected to the positive pole of the power supply; a titanium plate was used as the cathode, with a size of 5 cm x 5 cm x 0.5 mm, connected to the negative pole of the power supply; the spacing between the anode and the cathode plate was controlled to be 2 cm, 180 mL of 0.5 mol / L Na2S04 was used as the electrolyte, and an electrolytic cell was formed. After 90 minutes of reaction at a stable voltage of 3.0 V, a lithium-rich electrolyte was obtained. Na3P04 was added to the electrolyte to obtain Li3P04 precipitate, and after filtration and drying, Li3P04 product was obtained. The Li3P04 product was characterized by X-ray powder diffraction, and the results are shown in Figure 2

[0155] Table 3 Metal leaching rate in LiFeP04

[0156]

[0157] Example 3

[0158] An anode was prepared using retired lithium cobalt oxide (LiCo02) battery cathode powder, with a size of 5 cm x 5 cm x 0.5 mm, connected to the positive pole of the power supply; a titanium plate was used as the cathode, with a size of 5 cm x 5 cm x 0.5 mm, connected to the negative pole of the power supply; the spacing between the anode and the cathode plate was controlled to be 2 cm, 180 mL of seawater was used as the electrolyte, and an electrolytic cell was formed. After 90 minutes of reaction at a stable voltage of 2.5 V, a lithium-rich electrolyte was obtained. Then the pH of the electrolyte was adjusted to 13 with 1 mol / L KOH, and the calcium and magnesium impurities were precipitated to obtain the supernatant. K2C03 was added to the supernatant to obtain Li2C03 precipitate, and after filtration and drying, Li2C03 product was obtained.

[0159] Table 4 Metal leaching rate in LiCo02

[0160]

[0161] Example 4

[0162] An anode was prepared using retired lithium cobalt oxide (LiCo02) battery cathode powder, with a size of 5 cm x 5 cm x 0.5 mm, connected to the positive pole of the power supply; a titanium plate was used as the cathode, with a size of 5 cm x 5 cm x 0.5 mm, connected to the negative pole of the power supply; the spacing between the anode and the cathode plate was controlled to be 2 cm, 180 mL of seawater was used as the electrolyte, and an electrolytic cell was formed. After 90 minutes of reaction at a stable voltage of 2.5 V, a lithium-rich electrolyte was obtained. Then the pH of the electrolyte was adjusted to 13 with 1 mol / L KOH, and the calcium and magnesium impurities were precipitated to obtain the supernatant. K2C03 was added to the supernatant to obtain Li2C03 precipitate, and after filtration and drying, Li2C03 product was obtained.

[0163] Table 5 Metal leaching rate in LiMn204

[0164] ​

[0165] Example 5

[0166] Anode was prepared using retired nickel-cobalt-manganese ternary lithium battery (Li(Ni 0.6 Co 0.2 Mn 0.2 )O2) cathode powder, with a size of 5 cm x 5 cm x 0.5 mm, connected to the positive pole of the power supply; titanium plate was used as the cathode, with a size of 5 cm x 5 cm x 0.5 mm, connected to the negative pole of the power supply; the distance between the anode and the cathode plate was controlled to be 2 cm, 180 mL of NaCl with a concentration of 0.5 mol / L was used as the electrolyte, to form an electrolytic cell. After 90 minutes of reaction under a stable voltage of 2.5 V, a lithium-rich electrolyte was obtained. K2CO3 was added to the electrolyte to obtain Li2CO3 precipitate, and after filtration and drying, Li2CO3 product was obtained.

[0167] Table 6 Metal leaching rate in Li(Ni 0.8 Co 0.1 Mn 0.1 )O2

[0168]

[0169] Example 6

[0170] Anode was prepared using lithium spodumene powder, with a size of 5 cm x 5 cm x 0.5 mm, connected to the positive pole of the power supply; titanium plate was used as the cathode, with a size of 5 cm x 5 cm x 0.5 mm, connected to the negative pole of the power supply; the distance between the anode and the cathode plate was controlled to be 2 cm, 180 mL of NaCl with a concentration of 0.5 mol / L was used as the electrolyte, to form an electrolytic cell. After 90 minutes of reaction under a stable voltage of 2.5 V, a lithium-rich electrolyte was obtained. K2CO3 was added to the electrolyte to obtain Li2CO3 precipitate, and after filtration and drying, Li2CO3 product was obtained.

[0171] Table 7 Metal leaching rate in lithium spodumene

[0172]

[0173] The application has been described in detail above in connection with the embodiments, but the application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application.

Claims

1. A method for recovering lithium resources, characterized by, The method comprises the following steps: S1: applying a slurry containing lithium resources on a current collector to obtain an anode; S2: constructing an electrolytic cell by combining the anode with a cathode and an electrolyte solution; S3: performing electrode plate oxidation driven by an electric field and in-situ electrolyte oxidation driven by electrocatalysis on the electrolytic cell under power supply conditions, and leaching lithium from the anode through electrode plate oxidation driven by an electric field and in-situ electrolyte oxidation driven by electrocatalysis to obtain a lithium-containing electrolyte; S4: obtaining supernatant after filtering impurities in the lithium-containing electrolyte, and adding a precipitant to the supernatant to obtain a lithium-containing precipitate; In step S1, the lithium resources are one of retired lithium-ion battery positive electrode powder and lithium ore powder. In step S2, the electrolyte solution is a salt solution capable of forming active species with oxidation ability under anode oxidation, and the salt solution comprises at least one of a chlorine salt solution, a bromine salt solution, an iodine salt solution, and a sulfuric acid salt solution, wherein the chlorine salt solution is sodium chloride or natural seawater electrolyte, the bromine salt solution is sodium bromide electrolyte, the iodine salt solution is sodium iodide electrolyte, and the sulfuric acid salt solution is sodium sulfate electrolyte.

2. The recycling method according to claim 1, characterized in that, The current collector comprises at least one of a titanium plate current collector, a carbon cloth current collector, a steel plate current collector, and an iron plate current collector.

3. The recycling method according to claim 1, characterized in that, The lithium-containing precipitate comprises lithium carbonate, lithium phosphate, and lithium oxalate.

4. The recycling method according to any one of claims 1 to 3, characterized in that, The working voltage of the electrolysis process is ≤36V.

5. The recycling method according to any one of claims 1 to 3, characterized in that, The working time of the electrolysis process is ≤120min.

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