Method for recycling valuable metals in co-calcination product of retired lithium iron phosphate and ternary positive electrode material

Abstract

The present application relates to a kind of valuable metal in the method for recycling decommissioned lithium iron phosphate and ternary positive electrode material co-calcination product, comprising the following steps: S1: decommissioned lithium iron phosphate and ternary positive electrode material are mixed uniformly with molar ratio 1.5:1 are placed in nitrogen protection under the pipe still and are calcined, and obtain co-calcination product;S2: the obtained co-calcination product is placed in (NH4) 2 SO4-NH3·H2O system and carries out ammonia leaching reaction, and lithium, nickel and cobalt element are selectively leached out;S3: after ammonia leaching, by solid-liquid separation, lithium, nickel, cobalt ion-containing ammonia leaching solution and manganese, iron element-containing ammonia leaching residue are obtained;S5: in electrolytic cell, the nickel, cobalt ion in ammonia leaching solution is electrodeposited by electrochemical deposition method, and then is recovered in the form of alloy, and lithium element remaining in the electrodeposition residual liquid is obtained Li (NH4) (SO4) product by evaporation crystallization;S6: the manganese in ammonia leaching residue is obtained iron residue product and manganese-containing solution by water leaching, and the obtained manganese-containing solution is obtained (NH4) 2 Mn (SO4) 2·6H2O product by evaporation crystallization.

Description

Technical Field

[0001] This invention relates to the field of waste lithium-ion battery recycling, and in particular to a method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials. Background Technology

[0002] The rapid development of the new energy industry has driven an explosive growth in the production and sales of lithium-ion power batteries. Ternary lithium batteries and lithium iron phosphate batteries have the largest installed bases, each accounting for approximately 45% of the total market. In the process of recovering valuable metals, lithium iron phosphate materials typically require oxidation to release high-value lithium resources from the crystal lattice; while ternary materials require the addition of reducing agents to reduce high-valence transition metals (Ni3+, Co3+, and Mn4+), which is more conducive to the recovery of valuable metals. Heat treatment is a commonly used pretreatment method in the recycling of retired lithium-ion battery materials. Under anaerobic conditions, lithium iron phosphate and ternary electrode materials can act as redox agents for each other, complementing each other to complete the required redox reactions, thus avoiding additional resource consumption. Furthermore, the recycling of different types of lithium-ion batteries inevitably involves mixed recycling. Co-calcination can achieve the desired recovery of valuable metals from both electrode materials, and the resulting co-calcined product is beneficial for the recovery of valuable metals using hydrometallurgical methods.

[0003] Furthermore, in hydrometallurgical processes, acid dissolution (using organic or inorganic acids) is often used to ionize valuable metals, resulting in low selectivity and the complete dissolution of multiple metals into the solution, posing a significant challenge to subsequent separation and extraction. Simultaneously, recovering valuable metals such as lithium, nickel, cobalt, and manganese from the leachate typically requires complex steps including precipitation, extraction, back-extraction, membrane separation, and adsorption. This results in lengthy recovery processes, large equipment investments, and substantial reagent consumption, increasing recovery costs and environmental pressure. The co-calcination product of lithium iron phosphate and ternary cathode materials contains multiple metals, including lithium phosphate, nickel monoxide, cobalt monoxide, elemental nickel and cobalt, manganese monoxide, and iron(III) oxide. Currently, there are no reported methods for recovering valuable metals from this co-calcination product.

[0004] Therefore, there is an urgent need to develop a highly selective, targeted, and streamlined method to achieve efficient recovery of valuable metals from the co-calcination products of lithium iron phosphate and ternary cathode materials. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials to address the issues raised above.

[0006] A method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials includes the following steps:

[0007] S1: The retired lithium iron phosphate and ternary cathode material were uniformly mixed at a molar ratio of 1.5:1 and then placed in a tube furnace under nitrogen protection for calcination for 1.5 hours at a calcination temperature of 600℃ to obtain the co-calcined product.

[0008] S2: The obtained co-calcined product is placed in the (NH4)2SO4-NH3·H2O system for ammonia leaching reaction, and lithium, nickel and cobalt elements are selectively leached out; the selective leaching of lithium, nickel and cobalt elements is achieved through the complexation of ammonium ions.

[0009] S3: After ammonia leaching, ammonia leaching solution containing lithium, nickel, and cobalt ions and ammonia leaching residue containing manganese and iron elements are obtained by solid-liquid separation.

[0010] S4: An electrolytic cell with a titanium-based ruthenium-iridium oxide coated electrode as the anode and a titanium plate as the cathode is passed through an ammonia immersion solution;

[0011] S5: Nickel and cobalt ions in the ammonia leaching solution are electrodeposited in an electrolytic cell and recovered in the form of an alloy. The remaining lithium element in the electrodeposition residue is then evaporated and crystallized to obtain Li(NH4)(SO4) product.

[0012] S6: Manganese in ammonia leaching residue is leached with water to obtain iron slag product and manganese-containing solution. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product.

[0013] In one embodiment, in step S1, the ternary cathode material is one or a mixture of several of NCM111, NCM523, NCM622, and NCM811 materials.

[0014] In one embodiment, in step S2, the concentration of (NH4)2SO4 in the (NH4)2SO4-NH3·H2O system is 1-3 mol / L, the concentration of NH3·H2O is 2-4 mol / L, the solid-liquid ratio is 5-20 g / L, the leaching temperature of the ammonia leaching reaction is 60-120℃, and the ammonia leaching time is 1-3 h.

[0015] In one embodiment, in step S5, the voltage in the electrochemical deposition method is 4-8V, and electrolysis is performed at room temperature for 3-9 hours.

[0016] In one embodiment, in step S6, the solid-liquid ratio in the water immersion method is 50-150 g / L, the temperature is 25-90°C, and the reaction time is 0.5 h.

[0017] The above-mentioned method for recovering valuable metals in the co-calcination product of retired lithium iron phosphate and ternary cathode materials is highly targeted and easy to implement. It provides a simple and efficient approach for the recovery of multi-electrode material blends in the process of large-scale lithium-ion battery resource utilization, and realizes the efficient resource utilization of multiple metals in the co-calcination product of retired lithium iron phosphate and ternary cathode materials. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the technical process of the present invention;

[0019] Figure 2 The image shows the XRD pattern of the ammonia leaching residue from Example 1.

[0020] Figure 3 The image shows the SEM-EDS image of the nickel-cobalt alloy obtained by electrochemical co-deposition in Example 1.

[0021] Figure 4 The image shows the XRD pattern of the lithium product obtained by evaporation and crystallization in Example 1.

[0022] Figure 5 The image shows the XRD pattern of the manganese product obtained by evaporation and crystallization in Example 1. Detailed Implementation

[0023] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] As used herein, the terms “prepared from” and “comprising” are synonymous. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0025] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0026] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of this invention do not impose any limitation on the quantity requirement (i.e., the number of times) of the elements or components. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers to the singular form.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] A method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials includes the following steps:

[0029] S1: Retired lithium iron phosphate and ternary cathode material are uniformly mixed at a molar ratio of 1.5:1 and then placed in a tube furnace under nitrogen protection for calcination for 1.5 hours at a calcination temperature of 600℃ to obtain a co-calcined product; the ternary cathode material is one or a mixture of NCM111, NCM523, NCM622, and NCM811 materials; the obtained co-calcined product mainly consists of: lithium phosphate, nickel monoxide, cobalt monoxide, nickel-cobalt element, manganese monoxide, and iron(III) oxide.

[0030] S2: The obtained co-calcined product is placed in an (NH4)2SO4-NH3·H2O system for ammonia leaching reaction, and lithium, nickel and cobalt elements are selectively leached out; the concentration of (NH4)2SO4 in the (NH4)2SO4-NH3·H2O system is 1-3 mol / L, the concentration of NH3·H2O is 2-4 mol / L, the solid-liquid ratio is 5-20 g / L, the leaching temperature of the ammonia leaching reaction is 60-120℃, and the ammonia leaching time is 1-3 h.

[0031] S3: After ammonia leaching, ammonia leaching solution containing lithium, nickel, and cobalt ions and ammonia leaching residue containing manganese and iron elements are obtained by solid-liquid separation.

[0032] S4: An electrolytic cell with a titanium-based ruthenium-iridium oxide coated electrode as the anode and a titanium plate as the cathode is passed through an ammonia immersion solution;

[0033] S5: Nickel and cobalt ions in the ammonia leaching solution are electrodeposited in an electrolytic cell and recovered in the form of an alloy. The remaining lithium element in the electrodeposition residue is then evaporated and crystallized to obtain Li(NH4)(SO4) product. The voltage in the electrochemical deposition method is 4-8V, and electrolysis is carried out at room temperature for 3-9 hours. Since nickel and cobalt ions form complexes with ammonium ions, the oxidation of the anode during the electrodeposition process can break the coordination structure of the complexes, release metal ions and free ammonia, and promote the reduction deposition and recovery of nickel and cobalt ions at the cathode.

[0034] S6: Manganese in ammonia leaching residue is leached with water to obtain iron slag product and manganese-containing solution. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product. The solid-liquid ratio in the water leaching process is 50-150 g / L, the temperature is 25-90℃, and the reaction time is 0.5 h.

[0035] It should be noted that lithium, nickel, and cobalt elements in the co-calcined product can be selectively leached through the (NH4)2SO4-NH3·H2O system, effectively avoiding the interference of too many types of metal ions entering the electrochemical reaction system and hindering the co-deposition of the target metal. Since ammonium ions in the ammonia leaching process have a complexing effect on nickel and cobalt ions, conventional precipitation methods have poor precipitation results or still require the addition of a certain amount of complex-breaking reagents. This invention breaks the coordination structure of the complex through an electrochemical anodic reaction and simultaneously achieves the co-deposition of nickel and cobalt ions at the cathode. Simultaneously, ammonia in the solution assists electrodeposition to obtain a uniform nickel-cobalt alloy deposition product; the lithium resources in the electrodeposition residue can be obtained as Li(NH4)(SO4) product through simple evaporation and crystallization.

[0036] In addition, in step S6, manganese and iron elements exist in the ammonia leaching residue in the form of (NH4)2Mn(SO4)2 and Fe3O4, respectively. Taking advantage of the fact that (NH4)2Mn(SO4)2 is easily soluble in water, manganese resources can be recovered from the ammonia leaching residue by simple water leaching. After the water leaching is completed and filtered, iron slag product and manganese-containing solution are obtained. The manganese-containing solution is evaporated and crystallized to obtain manganese product.

[0037] Example 1

[0038] A method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials includes the following steps:

[0039] S1: Retired lithium iron phosphate and NCM111 ternary cathode material were uniformly mixed at a molar ratio of 1.5:1 and then placed in a tube furnace under nitrogen protection for calcination for 1.5 hours at a calcination temperature of 600℃ to obtain co-calcined products. The co-calcined products mainly consisted of lithium phosphate, nickel monoxide, cobalt monoxide, nickel-cobalt elements, manganese monoxide, and iron(III) oxide.

[0040] S2: The co-calcined product of retired lithium iron phosphate and NCM111 ternary cathode material was placed in an ammonia leaching reaction vessel. The reaction was carried out for 1 hour under the following conditions: initial concentrations of (NH4)2SO4 and NH3·H2O of 1 mol / L and 4 mol / L, solid-liquid ratio of 20 g / L, and ammonia leaching temperature of 120℃. The selective leaching efficiencies of lithium, nickel, and cobalt were 99.27%, 99.16%, and 99.11%, respectively, achieved through the complexation of ammonium ions. The XRD results of the ammonia leaching residue of the co-calcined product of retired lithium iron phosphate and ternary cathode material are shown below. Figure 2 As shown.

[0041] S3: After ammonia leaching, ammonia leaching solution containing lithium, nickel, and cobalt ions and ammonia leaching residue containing manganese and iron elements are obtained by solid-liquid separation.

[0042] S4: An electrolytic cell with a titanium-based ruthenium-iridium oxide coated electrode as the anode and a titanium plate as the cathode is passed through an ammonia immersion solution;

[0043] S5: Nickel and cobalt ions in an ammonia leaching solution were electrodeposited in an electrolytic cell and recovered as an alloy. The remaining lithium in the electrodeposition residue was then evaporated and crystallized to obtain Li(NH4)(SO4) product. After co-deposition of nickel and cobalt ions at 4V for 9 hours, 99.15% of nickel and 99.24% of cobalt were recovered as an alloy. The SEM-EDS results of the electrochemically co-deposited nickel-cobalt alloy are shown below. Figure 3 As shown; XRD results of the evaporated and crystallized lithium product are as follows. Figure 4 As shown.

[0044] S6: Manganese in the ammonia leaching residue was leached with water to obtain iron slag and a manganese-containing solution. The manganese-containing solution was then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O. In the ammonia leaching residue, manganese and iron exist in the forms of (NH4)2Mn(SO4)2 and Fe3O4, respectively. Utilizing the water solubility of (NH4)2Mn(SO4)2, 99.24% of the manganese resources can be recovered from the ammonia leaching residue by leaching in water at a solid-liquid ratio of 50 g / L and a temperature of 25℃ for 0.5 h. After filtration following the water leaching, iron slag and a manganese-containing solution were obtained. The manganese-containing solution was then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O. The XRD results of the manganese product recovered by evaporation and crystallization are shown below. Figure 5As shown.

[0045] Example 2

[0046] A method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials includes the following steps:

[0047] S1: The retired lithium iron phosphate and NCM523 ternary cathode material were uniformly mixed at a molar ratio of 1.5:1 and then placed in a tube furnace under nitrogen protection for calcination for 1.5 hours at a calcination temperature of 600℃ to obtain the co-calcined product.

[0048] S2: The product of co-calcination of retired lithium iron phosphate and NCM523 ternary cathode material was placed in an ammonia leaching reaction vessel. The reaction was carried out for 2 hours under the conditions of initial concentration of (NH4)2SO4 and NH3·H2O of 2 mol / L, solid-liquid ratio of 10 g / L and ammonia leaching temperature of 90℃. The selective leaching efficiency of lithium, nickel and cobalt was 99.51%, 99.47% and 99.38% respectively, by relying on the complexation of ammonium ions.

[0049] S3: After ammonia leaching, ammonia leaching solution containing lithium, nickel, and cobalt ions and ammonia leaching residue containing manganese and iron elements are obtained by solid-liquid separation.

[0050] S4: An electrolytic cell with a titanium-based ruthenium-iridium oxide coated electrode as the anode and a titanium plate as the cathode is passed through an ammonia immersion solution;

[0051] S5: Nickel and cobalt ions in the ammonia leaching solution are electrodeposited in an electrolytic cell and recovered in the form of an alloy. The remaining lithium element in the electrodeposition residue is then obtained by evaporation and crystallization to obtain Li(NH4)(SO4) product. After co-depositing nickel and cobalt ions at 6V for 6 hours, 99.27% ​​of nickel and 99.13% of cobalt are recovered in the form of an alloy.

[0052] S6: Manganese in the ammonia leaching residue is leached with water to obtain iron slag product and manganese-containing solution. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product. In the ammonia leaching residue, manganese and iron elements exist in the form of (NH4)2Mn(SO4)2 and Fe3O4, respectively. Taking advantage of the easy solubility of (NH4)2Mn(SO4)2 in water, 99.33% of the manganese resources can be recovered from the ammonia leaching residue by leaching with water at a solid-liquid ratio of 100 g / L and a temperature of 50℃ for 0.5 h. After leaching and filtration, iron slag product and manganese-containing solution are obtained. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product.

[0053] Example 3

[0054] A method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode materials includes the following steps:

[0055] S1: The retired lithium iron phosphate and NCM622+NCM811 ternary cathode material were uniformly mixed at a molar ratio of 1.5:1 and then placed in a tube furnace under nitrogen protection for calcination for 1.5 hours at a calcination temperature of 600℃ to obtain the co-calcined product.

[0056] S2: The product of co-calcination of retired lithium iron phosphate and NCM622+NCM811 ternary cathode material was placed in an ammonia leaching reaction vessel. The reaction was carried out for 3 hours under the conditions of initial concentration of (NH4)2SO4 and NH3·H2O of 3 mol / L, solid-liquid ratio of 5 g / L and ammonia leaching temperature of 60℃. The selective leaching efficiency of lithium, nickel and cobalt was 99.65%, 99.49% and 99.46% respectively, by relying on the complexation of ammonium ions.

[0057] S3: After ammonia leaching, ammonia leaching solution containing lithium, nickel, and cobalt ions and ammonia leaching residue containing manganese and iron elements are obtained by solid-liquid separation.

[0058] S4: An electrolytic cell with a titanium-based ruthenium-iridium oxide coated electrode as the anode and a titanium plate as the cathode is passed through an ammonia immersion solution;

[0059] S5: Nickel and cobalt ions in the ammonia leaching solution are electrodeposited in an electrolytic cell and recovered in the form of an alloy. The remaining lithium element in the electrodeposition residue is then obtained by evaporation and crystallization to obtain Li(NH4)(SO4) product. After co-depositing nickel and cobalt ions at 8V for 3 hours, 99.34% of nickel and 99.28% of cobalt are recovered in the form of an alloy.

[0060] S6: Manganese in the ammonia leaching residue is leached with water to obtain iron slag product and manganese-containing solution. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product. In the ammonia leaching residue, manganese and iron elements exist in the form of (NH4)2Mn(SO4)2 and Fe3O4, respectively. Taking advantage of the easy solubility of (NH4)2Mn(SO4)2 in water, 99.41% of the manganese resources can be recovered from the ammonia leaching residue by leaching with water at a solid-liquid ratio of 150 g / L and a temperature of 90℃ for 0.5 h. After leaching and filtration, iron slag product and manganese-containing solution are obtained. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product.

[0061] The above-mentioned method for recovering valuable metals in the co-calcination product of retired lithium iron phosphate and ternary cathode materials is highly targeted and easy to implement. It provides a simple and efficient approach for the recovery of multi-electrode material blends in the process of large-scale lithium-ion battery resource utilization, and realizes the efficient resource utilization of multiple metals in the co-calcination product of retired lithium iron phosphate and ternary cathode materials.

[0062] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for recovering valuable metals from the co-calcination product of retired lithium iron phosphate and ternary cathode material, characterized in that, Includes the following steps: S1: The retired lithium iron phosphate and ternary cathode material were uniformly mixed at a molar ratio of 1.5:1 and then placed in a tube furnace under nitrogen protection for calcination for 1.5 hours at a calcination temperature of 600℃ to obtain the co-calcined product. S2: The obtained co-calcined product was placed in the (NH4)2SO4-NH3·H2O system for ammonia leaching reaction, and lithium, nickel and cobalt elements were selectively leached out; S3: After ammonia leaching, ammonia leaching solution containing lithium, nickel, and cobalt ions and ammonia leaching residue containing manganese and iron elements are obtained by solid-liquid separation. S4: An electrolytic cell with a titanium-based ruthenium-iridium oxide coated electrode as the anode and a titanium plate as the cathode is passed through an ammonia immersion solution; S5: Nickel and cobalt ions in the ammonia leaching solution are electrodeposited in an electrolytic cell and recovered in the form of an alloy. The remaining lithium element in the electrodeposition residue is then evaporated and crystallized to obtain Li(NH4)(SO4) product. S6: Manganese in ammonia leaching residue is leached with water to obtain iron slag product and manganese-containing solution. The manganese-containing solution is then evaporated and crystallized to obtain (NH4)2Mn(SO4)2·6H2O product.

2. The method for recovering valuable metals from the co-calcination product of decommissioned lithium iron phosphate and ternary cathode material according to claim 1, characterized in that, In step S1, the ternary cathode material is one or a mixture of several of NCM111, NCM523, NCM622, and NCM811 materials.

3. The method for recovering valuable metals from the co-calcination product of decommissioned lithium iron phosphate and ternary cathode material according to claim 1, characterized in that, In step S2, the concentration of (NH4)2SO4 in the (NH4)2SO4-NH3·H2O system is 1-3 mol / L, the concentration of NH3·H2O is 2-4 mol / L, the solid-liquid ratio is 5-20 g / L, the leaching temperature of the ammonia leaching reaction is 60-120℃, and the ammonia leaching time is 1-3 h.

4. The method for recovering valuable metals from the co-calcination product of decommissioned lithium iron phosphate and ternary cathode material according to claim 1, characterized in that, In step S5, the voltage in the electrochemical deposition method is 4-8V, and electrolysis is performed at room temperature for 3-9 hours.

5. The method for recovering valuable metals from the co-calcination product of decommissioned lithium iron phosphate and ternary cathode material according to claim 1, characterized in that, In step S6, the solid-liquid ratio in the water immersion method is 50-150 g / L, the temperature is 25-90℃, and the reaction time is 0.5 h.

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