Method for recycling valuable metal in waste lithium battery

Abstract

The invention discloses a method for recycling valuable metals in a waste lithium battery, which is characterized by comprising the following steps: mixing a positive electrode material in the waste lithium battery with a vulcanizing agent, and carrying out electric pulse heating and water leaching to obtain lithium carbonate and filter residues; and carrying out acid treatment and oxygen-containing roasting on the filter residues to obtain the ternary precursor material. The method for recovering the valuable metal in the waste lithium battery has the advantages of higher metal recovery rate and recovery purity, simplicity and high efficiency in operation, environment friendliness and higher economic benefit.

Description

Technical Field

[0001] The invention belongs to the field of resource recovery of waste lithium batteries, and specifically relates to a method for selectively recovering valuable metals in positive electrode materials of waste lithium batteries by using electric heating vulcanization technology. Background Art

[0002] Recycling battery metals from waste lithium batteries is conducive to promoting the sustainable development of the new energy industry. At present, the recycling process of waste lithium battery metals is based on hydrometallurgical technology. In order to improve the leaching efficiency of transition metals, it is necessary to reduce the valence of transition metals through processes such as high-temperature roasting or hydrogen peroxide reduction. These strengthening measures significantly increase the carbon footprint of the recycling process. Electrified metallurgical technology uses the Joule heating effect caused by the material itself or the conductive carrier to instantly achieve ultra-fast heating, and the electrothermal conversion efficiency is much higher than that of traditional electric heating technology. At present, many scholars have begun to study the use of electric heating technology to recycle waste lithium battery positive electrode materials and have achieved remarkable results. The Joule heating effect can change the physical and chemical structure of the surface or internal positive electrode material of waste lithium batteries, so as to realize the recycling of positive electrode materials. However, this method has problems such as the inability of positive electrode materials to be directly converted into metal resources, the collapse of the structure of positive electrode materials, long processing time, complex preparation process, and weak adaptability of raw materials.

[0003] Based on the above research, it is necessary to provide a method for electric heating separation and recovery of valuable metals in waste lithium batteries with high efficiency, environmental friendliness, and strong raw material adaptability, so as to achieve selective recovery of various types of waste lithium-ion battery metals. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art to a certain extent. To this end, the present invention provides a method for recovering valuable metals from waste lithium batteries, which has a high metal recovery rate and recovery purity, and is simple, efficient, and environmentally friendly to operate.

[0005] Therefore, in a first aspect of the present invention, the present invention provides a method for recovering valuable metals in waste lithium batteries, comprising the following steps:

[0006] The positive electrode material in the waste lithium battery is mixed with a vulcanizing agent, subjected to electric pulse heating, and water immersion to obtain lithium carbonate and filter residue;

[0007] The filter residue is treated with acid and calcined in the presence of oxygen to obtain a ternary precursor material.

[0008] The present invention utilizes electric pulse heating technology to effectively recover valuable metal elements from the positive electrode materials of waste lithium batteries. During the electric pulse heating process of the positive electrode material and the vulcanizing agent, the lithium in the positive electrode material reacts with the vulcanizing agent and is converted into lithium sulfate enriched on the surface of the positive electrode material particles. At room temperature, lithium sulfate is easily soluble in water, so efficient recovery of lithium can be achieved by further water immersion. In addition, under the transient high temperature of electric pulse heating, the valence state of nickel, cobalt, and manganese elements contained in the positive electrode material is reduced. Therefore, the use of exogenous reducing agents can be reduced or even eliminated during the acid treatment process, thereby effectively reducing indirect environmental emissions caused by the consumption of exogenous reducing agents during the acid leaching process. Therefore, the method for recovering valuable metals in waste lithium batteries of the present invention has a high metal recovery rate and recovery purity, is simple to operate, and is environmentally friendly.

[0009] In some embodiments, during electric pulse heating, the current is 110-130A and the electric pulse duration is 20-30s.

[0010] In some embodiments, the vulcanizing agent satisfies at least one of the following:

[0011] (1) The vulcanizing agent includes at least one of flue gas desulfurization gypsum, magnesium sulfate, iron sulfate, cobalt sulfate, nickel sulfate, and manganese sulfate; CaSO in the flue gas desulfurization gypsum 4 ·2H 2 O mass content ≥ 93%;

[0012] (2) The amount of the sulfurizing agent added is 10 to 50% of the mass of the positive electrode material.

[0013] In some embodiments, the water immersion satisfies at least one of the following:

[0014] (A) The liquid-to-solid ratio of water immersion is 5:1 to 10:1;

[0015] (B) The leaching time is 30 to 180 seconds, and the leaching temperature is 20 to 30°C.

[0016] In some embodiments, the water immersion further comprises:

[0017] After water immersion, a lithium-containing solution is obtained, and a saturated sodium carbonate solution is added to the lithium-containing solution to obtain lithium carbonate and filter residue.

[0018] In some embodiments, the step of subjecting the filter residue to acid treatment includes adding a dilute acid solution; the acid treatment satisfies at least one of the following:

[0019] (a) the dilute acid solution comprises at least one of sulfuric acid and hydrochloric acid;

[0020] (b) The concentration of the dilute acid solution is 0.1 to 0.5 M, and the liquid-to-solid ratio is 10:1 to 20:1;

[0021] (c) The acid treatment time is 20 to 40 minutes, and the temperature is 40 to 60°C.

[0022] In some embodiments, after the filter residue is subjected to acid treatment, the method further includes: evaporating and concentrating the leaching solution obtained after the acid treatment to obtain a slurry, and subjecting the slurry to oxygen-containing roasting.

[0023] In some embodiments, during the oxygen-containing calcination, the calcination temperature is 400-500° C., and the calcination time is 1-3 hours.

[0024] In some embodiments, the waste lithium batteries include at least one of ternary lithium 811 batteries, ternary lithium 622 batteries, ternary lithium 532 batteries, lithium cobalt oxide batteries, and lithium manganese oxide batteries.

[0025] In some embodiments, before the step of mixing the positive electrode material in the waste lithium battery with the vulcanizing agent for electric pulse heating, the following steps are also included:

[0026] Waste lithium batteries are discharged, crushed, screened and floated to obtain positive electrode materials.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] (1) The present invention utilizes electric pulse heating technology based on the Joule heat principle to treat the positive electrode materials of waste lithium batteries. The electric pulse heating device can heat the positive electrode materials from room temperature to a specified temperature within a few seconds. The transient high temperature preferentially volatilizes the lithium inside the positive electrode material particles to the particle surface. The lithium that subsequently migrates to the particle surface comes into contact with a thermally stable sulfurizing agent, undergoes a solid-solid phase sulfurization reaction, and is transformed into highly water-soluble lithium sulfate, thereby improving the lithium extraction efficiency and extraction purity.

[0029] (2) The transient high temperature formed by the electric pulse heating technology of the present invention reduces the valence of nickel, cobalt and manganese elements in the positive electrode material from +3, +3, +4 to +2, +2, +2, respectively. Therefore, the use of exogenous reducing agents can be reduced or even eliminated during the acid treatment process, effectively reducing the indirect environmental emissions caused by the consumption of exogenous reducing agents such as hydrogen peroxide during the acid leaching process.

[0030] (3) The present invention uses sulfur-containing compounds such as flue gas desulfurization gypsum as a vulcanizing agent in the electric pulse heating process. The flue gas desulfurization gypsum has strong thermal stability and a thermal decomposition temperature of up to 1700°C, which prevents the release of sulfur-containing gases such as sulfur dioxide and sulfur trioxide during the electrothermal vulcanization process and reduces environmental pollution. In terms of thermodynamics, calcium sulfate selectively undergoes a sulfidation reaction with lithium components, but does not undergo a sulfidation reaction with metals such as nickel, cobalt, and manganese.

[0031] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0033] Figure 1 The present invention is a flowchart of a method for recovering valuable metals from waste lithium batteries according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0035] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0036] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0037] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0038] In a first aspect of an embodiment of the present invention, the present invention provides a method for recovering valuable metals in waste lithium batteries, comprising the following steps:

[0039] The positive electrode material in the waste lithium battery is mixed with a vulcanizing agent, subjected to electric pulse heating, and water immersion to obtain lithium carbonate and filter residue;

[0040] The filter residue is treated with acid and calcined in the presence of oxygen to obtain a ternary precursor material.

[0041] In the present invention, the positive electrode material in the waste lithium battery is mixed with a vulcanizing agent for electric pulse heating. The electric pulse heating device can heat the positive electrode material from room temperature to a specified temperature within a few seconds to form a transient high temperature. According to the difference in saturated vapor pressure of lithium and nickel, cobalt and manganese metals in the positive electrode material, the lithium inside the positive electrode material particles is preferentially volatilized to the particle surface by using transient high temperature. The lithium that migrates to the particle surface then contacts with a thermally stable vulcanizing agent, undergoes a solid-solid phase sulfidation reaction, and is transformed into highly water-soluble lithium sulfate, thereby improving the efficiency of water leaching and lithium extraction. After the heating is completed, water leaching is performed and the mixture is rapidly cooled to room temperature. This extremely rapid temperature rise and fall can not only ensure the surface enrichment of lithium, but also minimize the gas phase volatilization of lithium components. Compared with the traditional tubular furnace roasting technology, the lithium heat loss rate of the present invention is low, only about 0.23%, which significantly improves the lithium recovery efficiency. At the same time, the metal-oxygen bond of nickel, cobalt and manganese metal oxides will break under the induction of transient high temperature, and the breaking of chemical bonds reduces the elemental valence of nickel, cobalt and manganese. Therefore, for the transition metal residue obtained after lithium extraction, the use of exogenous reducing agents can be reduced or even eliminated, and a higher nickel, cobalt and manganese metal extraction rate can be obtained by using a mild acid leaching environment, which reduces the indirect environmental emissions caused by the consumption of exogenous reducing agents such as hydrogen peroxide during the acid leaching process.

[0042] In addition, the present invention selects a vulcanizing agent with strong thermal stability as the electrothermal vulcanizing agent for electric pulse heating. The vulcanizing agent hardly undergoes thermal decomposition during the electrothermal vulcanization stage, which provides a guarantee for the release of sulfur-free gas in the present invention.

[0043] Therefore, the method for recovering valuable metals in waste lithium batteries of the present invention has high recovery rate and recovery purity, is simple and efficient to operate, is environmentally friendly, and has high economic benefits.

[0044] In some embodiments of the present invention, in the electric pulse heating, the current is 110-130A, and the electric pulse duration is 20-30s.

[0045] The present invention utilizes electric pulse technology to quickly heat an electric pulse heating device. According to an embodiment of the present invention, the electric pulse heating device includes a low-resistance carbon graphite boat. The graphite boat reaches the specified heating temperature within a few seconds. Specifically, the positive and negative electrodes of the power supply are connected to the two sides of the graphite boat, and a pulse current is applied to the graphite boat to convert electrical energy into thermal energy. By adjusting the current size to 110-130A and the duration to 20-30s, the electric heating vulcanization temperature of the waste positive electrode material is controlled, so that it undergoes a sufficient solid-solid phase vulcanization reaction with the vulcanizing agent, and is transformed into highly water-soluble lithium sulfate, thereby improving the efficiency of water leaching lithium, and improving the recovery rate and recovery purity of lithium. Therefore, the method for recovering valuable metals in waste lithium batteries of the present invention has a high lithium recovery rate and recovery purity.

[0046] As an example, the current is 110A, 111A, 112A, 113A, 114A, 115A, 116A, 117A, 118A, 119A, 120A, 121A, 122A, 123A, 124A, 125A, 126A, 127A, 128A, 129A, 130A, etc.

[0047] As an example, the electric pulse time is 20s, 21s, 22s, 23s, 24s, 25s, 26s, 27s, 28s, 29s, 30s, etc.

[0048] In some embodiments of the present invention, the vulcanizing agent satisfies at least one of the following:

[0049] (1) The vulcanizing agent includes at least one of flue gas desulfurization gypsum, magnesium sulfate, iron sulfate, cobalt sulfate, nickel sulfate, and manganese sulfate; CaSO in the flue gas desulfurization gypsum 4 ·2H 2 O mass content ≥ 93%;

[0050] (2) The amount of the sulfurizing agent added is 10 to 50% of the mass of the positive electrode material.

[0051] The vulcanizing agent used in the present invention has excellent thermal stability and can effectively prevent the release of sulfur-containing gases such as sulfur dioxide and sulfur trioxide during the electrothermal vulcanization process. Thermodynamically, the vulcanizing agent only undergoes a sulfidation reaction with the lithium component, and does not undergo a sulfidation reaction with transition metals such as nickel, cobalt, and manganese. This is the theoretical basis for selective vulcanization. Taking flue gas desulfurization gypsum as an example, in some cases where the output of flue gas desulfurization gypsum is high, if flue gas desulfurization gypsum is selected as a vulcanizing agent, not only the process cost is reduced, but also the coordinated disposal of multiple solid wastes is achieved. Therefore, the method of recovering valuable metals in waste lithium batteries of the present invention is environmentally friendly and has high economic benefits.

[0052] As an example, the amount of sulfiding agent added is 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, 50% of the mass of the positive electrode material.

[0053] In some embodiments of the present invention, water immersion satisfies at least one of the following:

[0054] (A) The liquid-to-solid ratio of water immersion is 5:1 to 10:1;

[0055] (B) The leaching time is 30 to 180 seconds, and the leaching temperature is 20 to 30°C.

[0056] In the present invention, the positive electrode material generates lithium sulfate after electric pulse heating, and a lithium sulfate solution is formed by water leaching. At room temperature, the water solubility of lithium sulfate reaches 257g / L. Therefore, compared with the traditional carbon thermal reduction process or carbon thermal shock process, water leaching of lithium has a higher lithium extraction efficiency. Efficient leaching of lithium can be achieved within 30 to 180 seconds. Therefore, the method for recovering valuable metals in waste lithium batteries of the present invention has a higher lithium recovery rate.

[0057] As an example, the liquid-to-solid ratio is 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0058] As an example, the leaching time is 30s, 50s, 70s, 90s, 110s, 130s, 150s, 170s, 180s, etc.

[0059] As an example, the leaching temperature is 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, etc.

[0060] In some embodiments of the present invention, the water immersion further comprises:

[0061] After water immersion, a lithium-containing solution is obtained, and a saturated sodium carbonate solution is added to the lithium-containing solution to obtain lithium carbonate and filter residue.

[0062] According to the embodiment of the present invention, a lithium-containing solution is obtained after water immersion, and its main component is lithium sulfate. Then, a saturated sodium carbonate solution is added to generate lithium carbonate that is slightly soluble in water. Then, the lithium carbonate is evaporated and concentrated, and the concentrated solution is filtered to obtain lithium carbonate powder and filter residue. Thus, lithium resources are effectively recovered. As a result, the lithium recovery rate is further improved.

[0063] In some embodiments of the present invention, the step of subjecting the filter residue to acid treatment includes adding a dilute acid solution; the acid treatment satisfies at least one of the following:

[0064] (a) the dilute acid solution comprises at least one of sulfuric acid and hydrochloric acid;

[0065] (b) The concentration of the dilute acid solution is 0.1 to 0.5 M, and the liquid-to-solid ratio is 10:1 to 20:1;

[0066] (c) The acid treatment time is 20 to 40 minutes, and the temperature is 40 to 60°C.

[0067] Through dilute acid leaching, metal ions such as nickel, cobalt, and manganese contained in the filter residue enter the solution to form sulfates such as nickel sulfate, cobalt sulfate, and manganese sulfate, which is convenient for subsequent processing steps. Since the valence of metals such as nickel, cobalt, and manganese is reduced from +3, +3, and +4 to +2, +2, and +2 respectively during the electric pulse heating treatment stage, the use of exogenous reducing agents can be reduced or even eliminated in the dilute acid leaching step. Therefore, the method for recovering valuable metals in waste lithium batteries of the present invention is simple to operate, highly efficient, and environmentally friendly.

[0068] As an example, the concentration of the dilute acid solution is 0.1 M, 0.2 M, 0.3 M, 0.4 M, 0.5 M, etc.

[0069] As an example, the liquid-to-solid ratio is 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, etc.

[0070] As an example, the acid treatment time is 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0071] As an example, the acid treatment temperature is 40°C, 42°C, 45°C, 47°C, 50°C, 52°C, 55°C, 60°C, etc.

[0072] In some embodiments of the present invention, after the filter residue is subjected to acid treatment, the method further comprises: evaporating and concentrating the leaching solution obtained after the acid treatment to obtain slurry, and subjecting the slurry to oxygen-containing roasting.

[0073] During the oxygen-containing roasting process, metal ions such as nickel, cobalt, and manganese combine with oxygen to generate ternary precursor materials such as manganese oxide, cobalt oxide, and nickel oxide. This can effectively recover valuable metals in lithium-ion batteries.

[0074] In some embodiments of the present invention, in the oxygen-containing calcination, the calcination temperature is 400-500° C. and the calcination time is 1-3 hours.

[0075] As an example, the firing temperature is 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, etc.

[0076] As an example, the calcination time is 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2.0 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, etc.

[0077] In some embodiments of the present invention, the waste lithium battery includes at least one of a ternary lithium 811 battery, a ternary lithium 622 battery, a ternary lithium 532 battery, a lithium cobalt oxide battery, and a lithium manganese oxide battery.

[0078] In some embodiments of the present invention, before the step of mixing the positive electrode material in the waste lithium battery with the vulcanizing agent for electric pulse heating, the following steps are also included:

[0079] Waste lithium batteries are discharged, crushed, screened and floated to obtain positive electrode materials.

[0080] According to an embodiment of the present invention, the residual voltage of the waste lithium battery is first discharged to avoid safety accidents in the subsequent battery disassembly process, and then the waste lithium battery is placed in an oven and dried at 80°C. After drying, the battery shell is disassembled, and the battery core is sheared and crushed, and the crushed material is placed in a sifter for vibration screening to obtain the above-screen products of aluminum foil, copper foil, and plastic, and the below-screen products are the positive and negative electrode mixed powders of the waste lithium battery. The positive and negative electrode mixed powders are then subjected to flotation treatment to remove excess impurities and negative electrode materials such as graphite, thereby obtaining a positive electrode material, in which the content and purity of lithium, nickel, cobalt, and manganese are higher, but a small amount of impurities such as aluminum and copper may still exist. In this way, the recovery purity and recovery rate of valuable metals can be further improved.

[0081] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0082] Embodiment 1:

[0083] (1) After discharging, crushing, screening and flotation of the waste ternary lithium NCM532 battery pack in sequence, 10 g of the waste positive electrode material powder was mixed with 5 g of flue gas desulfurization gypsum to obtain a mixture;

[0084] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, where the current is 120A and the pulse time is 30s, and performing an electrothermal vulcanization treatment;

[0085] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 10:1, the water leaching temperature is 25° C., the water leaching time is 30 seconds, and filtering is performed after the water leaching to obtain a lithium-rich solution and a filter residue;

[0086] (4) subjecting the filter residue to acid leaching treatment, wherein the acid leaching parameters are 0.1 M sulfuric acid, a liquid-to-solid ratio of 20:1, an acid leaching temperature of 50° C., an acid leaching time of 50 min, and filtering after acid leaching to obtain a leachate and a graphite residue;

[0087] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leached solution, and then calcining it in oxygen-enriched conditions at a calcination temperature of 450° C. for a calcination time of 2 h to obtain a ternary precursor.

[0088] According to the measurement, in this embodiment, the lithium extraction rate is 96.74%, the nickel, cobalt and manganese extraction rates are 97.8%, 99.4% and 95.7% respectively, the purity of the regenerated lithium carbonate is 99.7%, and the impurity metal content in the ternary precursor is less than 0.1%. Figure 1 shown.

[0089] Embodiment 2:

[0090] (1) After the waste lithium cobalt oxide battery pack is discharged, crushed, screened, and floated in sequence, 10 g of the waste positive electrode material powder is mixed with 4 g of flue gas desulfurization gypsum to obtain a mixture;

[0091] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, wherein the current is 130A and the pulse time is 20s, and then performing an electrothermal vulcanization treatment;

[0092] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 10:1, the water leaching temperature is 25° C., the water leaching time is 50 s, and filtering is performed after the water leaching to obtain a lithium-rich solution and a filter residue;

[0093] (4) acid leaching the filter residue, wherein the acid leaching parameters are 0.1 M hydrochloric acid, a liquid-to-solid ratio of 20:1, an acid leaching temperature of 60° C., an acid leaching time of 60 min, and filtering after acid leaching to obtain a leachate and graphite residue;

[0094] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leaching solution, and then roasting it in oxygen-enriched conditions at a roasting temperature of 450° C. and a roasting time of 2 h to obtain cobalt oxide.

[0095] It has been determined that in this embodiment, the lithium extraction rate is 97.2%, the cobalt extraction rate is 99.2%, the purity of the obtained regenerated lithium carbonate is 99.8%, and the impurity metal content in the cobalt oxide is less than 0.1%.

[0096] Embodiment 3:

[0097] (1) After discharging, crushing, screening and flotation of ternary lithium 811 batteries, ternary lithium 622 batteries, ternary lithium 532 batteries, lithium cobalt oxide batteries and lithium manganese oxide battery packs, 10 g of mixed waste positive electrode material powder was mixed with 3 g of flue gas desulfurization gypsum, 1 g of cobalt sulfate and 1 g of sodium sulfate to obtain a mixture;

[0098] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, wherein the current is 120A and the pulse time is 30s, and then performing an electrothermal vulcanization treatment;

[0099] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 10:1, the water leaching temperature is 25° C., the water leaching time is 60 s, and after the water leaching, filtering is performed to obtain a lithium-rich solution and a filter residue;

[0100] (4) acid leaching the filter residue, wherein the acid leaching parameters are 0.1 M sulfuric acid, a liquid-to-solid ratio of 10:1, an acid leaching temperature of 70° C., an acid leaching time of 60 min, and filtering after acid leaching to obtain a leachate and a graphite residue;

[0101] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leached solution, and then calcining it in oxygen-enriched conditions at a calcination temperature of 450° C. for a calcination time of 2 h to obtain a ternary precursor.

[0102] It has been determined that in this embodiment, the lithium extraction rate is 96.6%, the nickel, cobalt and manganese extraction rates are 98.3%, 98.9% and 97.3% respectively, the purity of the obtained regenerated lithium carbonate is 99.6%, and the impurity metal content in the ternary precursor is less than 0.1%.

[0103] Embodiment 4:

[0104] (1) After discharging, crushing, screening and flotation of ternary lithium 811 batteries, ternary lithium 622 batteries, ternary lithium 532 batteries, lithium cobalt oxide batteries and lithium manganese oxide battery packs, 10 g of mixed waste positive electrode material powder was mixed with 2.5 g of sodium sulfate and 2.5 g of manganese sulfate to obtain a mixture;

[0105] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, wherein the current is 110A and the pulse time is 30s, and then performing an electrothermal vulcanization treatment;

[0106] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 10:1, the water leaching temperature is 25° C., the water leaching time is 60 s, and after the water leaching, filtering is performed to obtain a lithium-rich solution and a filter residue;

[0107] (4) acid leaching the filter residue, wherein the acid leaching parameters are 0.1 M sulfuric acid, a liquid-to-solid ratio of 10:1, an acid leaching temperature of 70° C., an acid leaching time of 60 min, and filtering after acid leaching to obtain a leachate and a graphite residue;

[0108] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leached solution, and then calcining it in oxygen-enriched conditions at a calcination temperature of 450° C. for a calcination time of 2 h to obtain a ternary precursor.

[0109] It has been determined that in this embodiment, the lithium extraction rate is 97.1%, the nickel, cobalt and manganese extraction rates are 97.6%, 98.1% and 98.2% respectively, the purity of the obtained regenerated lithium carbonate is 99.7%, and the impurity metal content in the ternary precursor is less than 0.1%.

[0110] Embodiment 5:

[0111] (1) After discharging, crushing, screening and flotation of ternary lithium 811 batteries, ternary lithium 622 batteries, ternary lithium 532 batteries, lithium cobalt oxide batteries and lithium manganese oxide battery packs, 10 g of mixed waste positive electrode material powder was mixed with 1 g of flue gas desulfurization gypsum to obtain a mixture;

[0112] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, wherein the current is 130A and the pulse time is 30s, and then performing an electrothermal vulcanization treatment;

[0113] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 5:1, the water leaching temperature is 20° C., the water leaching time is 180 s, and filtering is performed after the water leaching to obtain a lithium-rich solution and a filter residue;

[0114] (4) acid leaching the filter residue, wherein the acid leaching parameters are 0.1 M sulfuric acid, a liquid-to-solid ratio of 10:1, an acid leaching temperature of 70° C., an acid leaching time of 60 min, and filtering after acid leaching to obtain a leachate and a graphite residue;

[0115] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leached solution, and then calcining it in oxygen-enriched conditions at a calcination temperature of 450° C. for a calcination time of 2 h to obtain a ternary precursor.

[0116] It has been determined that in this embodiment, the lithium extraction rate is 98.1%, the nickel, cobalt and manganese extraction rates are 98.1%, 97.9% and 97.9% respectively, the purity of the obtained regenerated lithium carbonate is 99.6%, and the impurity metal content in the ternary precursor is less than 0.1%.

[0117] Embodiment 6:

[0118] (1) After discharging, crushing, screening and flotation of ternary lithium 811 batteries, ternary lithium 622 batteries, ternary lithium 532 batteries, lithium cobalt oxide batteries and lithium manganese oxide battery packs, 10 g of mixed waste positive electrode material powder was mixed with 2 g of magnesium sulfate and 2 g of iron sulfate to obtain a mixture;

[0119] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, wherein the current is 120A and the pulse time is 20s, and then performing an electrothermal vulcanization treatment;

[0120] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 10:1, the water leaching temperature is 30° C., the water leaching time is 30 seconds, and filtering is performed after the water leaching to obtain a lithium-rich solution and a filter residue;

[0121] (4) acid leaching the filter residue, wherein the acid leaching parameters are 0.1 M sulfuric acid, a liquid-to-solid ratio of 10:1, an acid leaching temperature of 70° C., an acid leaching time of 60 min, and filtering after acid leaching to obtain a leachate and a graphite residue;

[0122] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leached solution, and then calcining it in oxygen-enriched conditions at a calcination temperature of 450° C. for a calcination time of 2 h to obtain a ternary precursor.

[0123] It has been determined that in this embodiment, the lithium extraction rate is 95.9%, the nickel, cobalt and manganese extraction rates are 96.3%, 96.7% and 97.4% respectively, the purity of the obtained regenerated lithium carbonate is 99.8%, and the impurity metal content in the ternary precursor is less than 0.1%.

[0124] Embodiment 7:

[0125] (1) After discharging, crushing, screening and flotation of ternary lithium 811 batteries, ternary lithium 622 batteries, ternary lithium 532 batteries, lithium cobalt oxide batteries and lithium manganese oxide battery packs, 10 g of mixed waste positive electrode material powder was mixed with 2 g of nickel sulfate and 3 g of manganese sulfate to obtain a mixture;

[0126] (2) placing the mixed material in a heated graphite boat, setting the electric pulse parameters, wherein the current is 130A and the pulse time is 20s, and then performing an electrothermal vulcanization treatment;

[0127] (3) extracting lithium from the electrothermal sulfidation product by water leaching, wherein the liquid-to-solid ratio of the water leaching is 10:1, the water leaching temperature is 25° C., the water leaching time is 60 s, and after the water leaching, filtering is performed to obtain a lithium-rich solution and a filter residue;

[0128] (4) acid leaching the filter residue, wherein the acid leaching parameters are 0.1 M sulfuric acid, a liquid-to-solid ratio of 10:1, an acid leaching temperature of 70° C., an acid leaching time of 60 min, and filtering after acid leaching to obtain a leachate and a graphite residue;

[0129] (5) adding a saturated sodium carbonate solution to the lithium-rich solution to obtain regenerated lithium carbonate after precipitation; evaporating and concentrating the leached solution, and then calcining it in oxygen-enriched conditions at a calcination temperature of 450° C. for a calcination time of 2 h to obtain a ternary precursor.

[0130] It has been determined that in this embodiment, the lithium extraction rate is 95.4%, the nickel, cobalt and manganese extraction rates are 96.3%, 97.4% and 96.3% respectively, the purity of the obtained regenerated lithium carbonate is 99.7%, and the impurity metal content in the ternary precursor is less than 0.1%.

[0131] The extraction rates of metal elements and the purity of lithium carbonate in all the above examples are shown in Table 1.

[0132] Table 1 Extraction rate of metal elements and lithium carbonate purity results in all examples

[0133] Serial number lithium nickel cobalt manganese Lithium carbonate purity Impurities Example 1 96.74％ 97.8％ 99.4％ 95.7％ 99.7％ <0.1％ Example 2 97.2％ / 99.2％ / 99.8％ <0.1％ Example 3 96.6％ 98.3％ 98.9％ 97.3％ 99.6％ <0.1％ Example 4 97.12％ 97.6％ 98.1％ 98.2％ 99.7％ <0.1％ Example 5 98.14％ 98.1％ 97.9％ 97.9％ 99.6％ <0.1％ Example 6 95.93％ 96.3％ 96.7％ 97.4％ 99.8％ <0.1％ Example 7 95.42％ 96.3％ 97.4％ 96.3％ 99.7％ <0.1％

[0134] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0135] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for recovering valuable metals from waste lithium batteries, characterized in that: The following steps are involved: The positive electrode material in the waste lithium battery is mixed with a vulcanizing agent, subjected to electric pulse heating, and water immersion to obtain lithium carbonate and filter residue; The filter residue is treated with acid and calcined in the presence of oxygen to obtain a ternary precursor material.

2. The method according to claim 1, characterized in that: In the electric pulse heating, the current is 110-130A, and the electric pulse duration is 20-30s.

3. The method according to claim 1 or 2, characterized in that: The vulcanizing agent satisfies at least one of the following: (1) The vulcanizing agent includes at least one of flue gas desulfurization gypsum, magnesium sulfate, sodium sulfate, iron sulfate, cobalt sulfate, nickel sulfate, and manganese sulfate; the mass content of CaSO4·2H2O in the flue gas desulfurization gypsum is ≥93%; (2) The amount of the vulcanizing agent added is 10 to 50% of the mass of the positive electrode material.

4. The method according to any one of claims 1 to 3, characterized in that: The water immersion satisfies at least one of the following: (A) the liquid-to-solid ratio of the water immersion is 5:1 to 10:1; (B) The leaching time is 30 to 180 seconds, and the leaching temperature is 20 to 30°C.

5. The method according to any one of claims 1 to 4, characterized in that: The water immersion also includes: After water immersion, a lithium-containing solution is obtained, and a saturated sodium carbonate solution is added to the lithium-containing solution to obtain lithium carbonate and filter residue.

6. The method according to claim 1, characterized in that The step of subjecting the filter residue to acid treatment includes adding a dilute acid solution; the acid treatment satisfies at least one of the following: (a) the dilute acid solution comprises at least one of sulfuric acid and hydrochloric acid; (b) the concentration of the dilute acid solution is 0.1 to 0.5 M, and the liquid-to-solid ratio is 10:1 to 20:1; (c) The acid treatment time is 20 to 40 minutes and the temperature is 40 to 60°C.

7. The method according to claim 1, characterized in that After the filter residue is treated with acid, the method further comprises: evaporating and concentrating the leaching solution obtained after the acid treatment to obtain slurry, and performing oxygen-containing roasting on the slurry.

8. The method according to claim 1, characterized in that In the oxygen-containing calcination, the calcination temperature is 400-500° C. and the calcination time is 1-3 hours.

9. The method according to any one of claims 1 to 8, characterized in that: The waste lithium battery includes at least one of a ternary lithium 811 battery, a ternary lithium 622 battery, a ternary lithium 532 battery, a lithium cobalt oxide battery, and a lithium manganese oxide battery.

10. The method according to claim 1, characterized in that Before the step of mixing the positive electrode material in the waste lithium battery with the vulcanizing agent for electric pulse heating, the following steps are also included: Waste lithium batteries are discharged, crushed, screened and floated to obtain positive electrode materials.

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