METHODS AND APPARATUSES FOR RECYCLING BATTERY CATHODE MATERIALS

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefits of U.S. Provisional Patent Application No. 63/710,482, entitled “METHODS AND APPARATUSES FOR RECYCLING BATTERY CATHODE MATERIALS,” filed Oct. 22, 2024, each of which is incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under Grant DE-EE0010400 awarded by the Department of Energy. The government has certain rights in the invention.

TECHNOLOGY FIELDS

The present application generally relates to battery recycling and, more particularly, to recycling spent lithium-ion battery cathode materials (e.g., LCO (Lithium Cobalt Oxide), NCM (Nickel Cobalt Manganese), etc.).

BACKGROUND

The increasing global demand for lithium-ion batteries, driven by the expansion of electric vehicles (EVs), renewable energy systems, and consumer electronics, has resulted in a growing need for effective recycling processes. Lithium-ion batteries contain critical minerals like lithium, cobalt, and nickel, which are essential for various high-tech applications, including renewable energy storage and electric mobility. The global production of lithium-ion batteries is expected to reach 4700 GWh by 2030, with about 1.2 million tons of these batteries projected to reach end-of-life during this period.

When lithium-ion batteries are improperly disposed of in landfills, they pose significant environmental hazards. These include the risk of fires due to battery punctures and the potential leaching of toxic heavy metals into the soil and groundwater. Moreover, fewer than 5% of lithium-ion batteries are currently recycled, resulting in the loss of valuable materials and contributing to the environmental burden of electronic waste. Recycling these batteries is not only a crucial step for environmental protection but also essential for securing the supply of critical minerals.

Traditional hydrometallurgical recycling processes involve the use of sulfuric acid and hydrogen peroxide to dissolve the valuable metals in spent cathode materials. However, these processes are energy-intensive, expensive, and produce hazardous waste that is difficult to manage. The release of sulfuric acid into the environment can harm aquatic ecosystems and contribute to air pollution. Additionally, the large quantities of waste generated during the recycling process pose logistical and economic challenges in terms of disposal and treatment.

SUMMARY

The following is a simplified summary of the disclosure in order to provide a basic understanding of some aspects of the disclosure. This summary is not an extensive overview of the disclosure. It is intended to neither identify key or critical elements of the disclosure, nor delineate any scope of the particular implementations of the disclosure or any scope of the claims. Its sole purpose is to present some concepts of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.

According to one or more aspects of the present disclosure, a method for battery recycling is provided. The method includes: pretreating raw cathode materials by heating the raw cathode materials in a reducing agent to chemically transform metal ions in the raw cathode materials from a higher oxidation state to a lower oxidation state, wherein the raw cathode materials are generated from spent batteries; performing a leaching process on the pretreated cathode materials to produce a leachate; recovering cathode materials from the leachate; and recycling and regenerating acid solution from the leachate.

In some embodiments, the reducing agent includes sugar.

In some embodiments, the reducing agent includes a carbon material.

In some embodiments, the reducing agent includes glucose.

In some embodiments, the raw cathode materials are pretreated at a temperature between about 100° C. and about 900° C.

In some embodiments, the raw cathode materials are pretreated for a time period of about 0.1 to 24 hours.

In some embodiments, the raw cathode materials are pretreated in a gas phase including at least one of air, N2, Ar, O2, or CO2.

In some embodiments, the raw cathode materials are pretreated in a gas phase with O₂ concentrations ranging from 1% to 50%.

In some embodiments, the raw cathode materials are pretreated additives including at least one of Na₂CO₃, NaHCO₃, K₂CO₃, or KHCO₃.

In some embodiments, the raw cathode materials include at least one of lithium cobalt oxide (LCO) or nickel-cobalt-manganese materials (NCM), wherein pretreating the raw cathode materials includes reducing LCO and NCM from higher oxidation states to lower oxidation states without fully reducing them to metallic states.

In some embodiments, pretreating the raw cathode materials includes reducing cobalt from Co³⁺ to Co²⁺.

In some embodiments, pretreating the raw cathode materials includes reducing nickel from Ni³⁺ to Ni²⁺.

In some embodiments, the leaching process includes dissolving the pretreated cathode materials in an aqueous solution of an organic acid.

In some embodiments, the organic acid includes at least one of a formic acid or a citric acid.

In some embodiments, the leaching process further includes adding hydrogen peroxide to the pretreated cathode materials.

In some embodiments, recovering the recycled cathode materials from the leachate includes adding oxalic acid to the leachate to precipitate the recycled cathode materials.

In some embodiments, the recycled cathode materials include at least one of cobalt oxalate or nickel oxalate.

In some embodiments, the method further includes recycling and regenerating, from the leachate, acid solution after the precipitation of the recycled cathode materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. The drawings, however, should not be taken to limit the disclosure to the specific embodiments, but are for explanation and understanding.

FIG. 1 is a flowchart illustrating an example process for recycling cathode battery materials in accordance with some embodiments of the present disclosure.

FIG. 2 illustrates a diagram depicting the remaining mass of cathode material following leaching with various acids.

FIG. 3 illustrates a plot showing the leaching time of reduced lithium cobalt oxide (LCO) using various acid solutions in accordance with some embodiments of the present disclosure.

FIG. 4 illustrates a diagram depicting the leaching time required for the complete dissolution of reduced nickel-cobalt-manganese (NCM) materials using various acid solutions.

FIG. 5 illustrates a plot comparing the effectiveness of formic acid and sulfuric acid in leaching raw nickel-cobalt-manganese (NCM) materials in accordance with some embodiments of the present disclosure.

FIG. 6 illustrates the X-ray Photoelectron Spectroscopy (XPS) analysis of lithium cobalt oxide (LCO), comparing the spectra of the raw and reduced forms of the material.

FIG. 7 illustrates the X-ray Photoelectron Spectroscopy (XPS) analysis of nickel-cobalt-manganese (NCM) material, comparing the spectra of raw NCM (red line) and reduced NCM (green line) in accordance with some embodiments of the present disclosure.

FIGS. 8A, 8B, 9A, and 9B illustrate Scanning Electron Microscopy (SEM) images depicting the surface morphology of raw and reduced lithium cobalt oxide (LCO) and nickel-cobalt-manganese (NCM) materials.

FIG. 10 is a flow diagram illustrating an example process for battery cathode materials recycling in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides mechanisms (e.g., systems, apparatuses, methods, etc.) for recycling spent batteries. As used herein, a battery may refer to any electric storage device. In some embodiments, the battery may be a lithium-ion battery (LIB). Spent batteries may include used and/or aged LIBs, battery modules, battery packs, etc. As used herein, “lithium-ion battery cathode material” refers to the material that constitutes the cathode of LIBs, including, but not limited to, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese aluminum oxide, lithium manganese oxide, lithium iron phosphate, and lithium manganese iron phosphate.

Recycling LIBs may involve discharging spent LIBs and processing the spent LIBs using physical methods such as dismantling, crushing, screening, and other mechanical processes. The residual materials that remain after the mechanical processing of the spent LIBs are commonly referred to as “black mass.” Black mass may contain carbon black, graphite, and organic binders such as ethylene carbonate, cellulose, and polyvinylidene fluoride (PVDF). These carbon materials can also act as reducing agents during the recycling process for the cathode materials. The raw anode materials and raw cathode materials may be separated and processed to produce recycled anode materials and recycled cathode materials, respectively.

The present disclosure provides mechanisms for recycling lithium-ion batteries through a hydrometallurgical recycling process utilizing organic acids to recover critical minerals such as lithium, cobalt, nickel, manganese, etc. These minerals are extracted from spent lithium-ion battery cathodes, including both lithium cobalt oxide (LCO) and nickel cobalt manganese (NCM) chemistries, which are commonly used in consumer electronics and electric vehicles (EVs). The mechanisms described herein offer a scalable, environmentally friendly alternative to traditional recycling methods, which typically involve hazardous materials and costly processes.

As the demand for electric vehicles and energy storage systems continue to rise, so does the need for sustainable and efficient recycling methods. Traditional processes rely heavily on sulfuric acid and hydrogen peroxide, both of which pose significant environmental and safety risks. The present disclosure provides a solution by using organic acids that are less hazardous, thereby reducing both environmental impact and operational costs. The process may also include a regeneration step that allows the reuse of the acid solution, making it more sustainable than existing methods for recycling battery cathode materials.

The present disclosure addresses the foregoing and other issues associated with conventional battery recycling methods by providing a green and cost-effective recycling method that uses organic acids such as formic acid and citric acid. These organic acids are less corrosive, safer to handle, and require less energy to produce than sulfuric acid. By using these acids in the recycling process, the mechanisms described herein minimize environmental harm while improving the efficiency of metal recovery from LCO and NCM cathode materials. The ability to recycle and regenerate the acid solution further enhances the sustainability of the process, making it a promising solution for large-scale recycling operations.

In some embodiments, a hydrometallurgical process for recycling lithium-ion battery cathodes is provided. This process may be particularly effective for LCO and NCM chemistries. The pretreatment that reduces cobalt from Co³⁺ to Co²⁺ and nickel from Ni³⁺ to Ni²⁺, may cause these metals to be more reactive during the subsequent leaching process. By increasing the reactivity of the cathode material, the pretreatment step may significantly improve the efficiency and rate of the leaching process. Additionally, the reduction in particle size during pretreatment increases the surface area of the material, further enhancing reaction kinetics.

In the pretreatment process, raw cathode materials, including both LCO and NCM, are pretreated by heating with a reducing agent, such as glucose, for pretreatment. In some embodiments, other sugars (e.g., fructose, galactose, lactose, maltose, starch, cellulose, etc.), or carbon materials may be used as the reducing agent. In some embodiments, the reducing agent may include a carbon material present in the black mass obtained after the mechanical processing of spent batteries.

A leaching process may be performed on the pretreated cathode materials. The leaching process may involve dissolving the pretreated cathode materials using aqueous solutions of organic acids, such as formic acid and citric acid. The organic acids are safer and less harmful than traditional inorganic acids like sulfuric acid. They may reduce environmental risks and operational costs while providing comparable or superior performance in terms of leaching efficiency. Additionally, organic acids require less energy to produce, further reducing the environmental footprint of the recycling process.

The leaching process utilizes the reactivity of organic acids such as formic acid or citric acid and may effectively dissolve the valuable metals without the need for hazardous inorganic acids like sulfuric acid. The use of organic acids in the leaching process offers several key advantages over traditional methods. These acids are less harmful to the environment, require lower energy inputs, and produce fewer harmful byproducts. Furthermore, the process does not always require the use of hydrogen peroxide, which is commonly added to accelerate the leaching reaction in traditional recycling methods. Instead, the pretreatment of the cathode material achieves similar efficiency gains by enhancing the solubility of cobalt and nickel.

The leachate may be treated with oxalic acid to precipitate cobalt and nickel as cobalt oxalate and nickel oxalate. In some embodiments, the leachate may be treated after the metals have been dissolved. The resulting precipitates are insoluble in water, making them easy to filter and recover. The remaining acid solution may then be regenerated and recycled for use in subsequent leaching cycles, creating a closed-loop system that may minimize waste and improve the overall sustainability of the process. The entire process is designed to be adaptable for industrial-scale recycling operations, offering a greener alternative to conventional methods while maintaining high recovery rates for critical minerals.

The organic acid leaching process utilizes aqueous solutions of organic acids, such as formic acid and citric acid, to dissolve pretreated cathode materials. These organic acids are safer and less harmful than traditional inorganic acids such as sulfuric acid, thereby reducing environmental risks and operational costs while offering similar or superior leaching efficiency. Furthermore, organic acids require less energy to produce, further decreasing the environmental footprint of the recycling process.

In some embodiments, formic acid may be used as the leaching agent. In such embodiments, the use of hydrogen peroxide can be eliminated, thereby reducing both the cost and complexity of the recycling process. However, for untreated cathode materials, the addition of hydrogen peroxide (at approximately 5% by volume) may still be employed to accelerate the leaching reaction and achieve faster dissolution rates. The flexibility of this process makes it adaptable to a wide range of recycling scenarios.

Recycled cathode materials, such as cobalt and nickel, may be recovered following the leaching process. For example, oxalic acid may be added to the leachate to precipitate cobalt and nickel as their respective oxalates. These metal oxalates are insoluble in water and can be readily separated from the solution by filtration. The recovered oxalates may then be further processed to produce high-purity cobalt and nickel for reuse in battery manufacturing or other industrial applications. The remaining solution may be regenerated and recycled for use in subsequent leaching cycles, thereby further improving the sustainability and cost-effectiveness of the process.

FIG. 1 is a flowchart illustrating an example process 100 for recycling cathode battery materials in accordance with some embodiments of the present disclosure.

At 110, raw cathode materials may be separated from spent battery materials. For example, this step may involve disassembling battery modules to extract individual cathode materials. In some embodiments, step 110 may be omitted. For example, this step can be omitted when the raw cathode materials have already been separated in a prior process.

At 120, the raw cathode materials may be pretreated. This pretreatment may involve a reduction process that chemically transforms metal ions from higher oxidation states to lower oxidation states, thereby increasing their reactivity and facilitating their dissolution in subsequent processing steps. The reduction process may be conducted by heating the cathode materials with a reducing agent under controlled conditions. For example, cobalt may be reduced from Co³⁺ to Co²⁺, and nickel from Ni³⁺ to Ni²⁺, making them more reactive and easier to dissolve during the subsequent leaching process. In some embodiments, the pretreatment of the spent cathode materials may involve heating them with a reducing agent (e.g., glucose) at a suitable temperature (e.g., 100° C.-900° C.) for a suitable period of time (0.1 hour-24 hours) in a gaseous atmosphere such as air, nitrogen (N₂), argon (Ar), oxygen (O₂), carbon dioxide (CO₂), or combinations thereof.

The reduction of lithium cobalt oxide (LCO) may be represented by the following equation:

Similarly, the reduction process for NCM811, which is one example of nickel-cobalt-manganese materials (NCM), may be represented as follows:

It should be noted that other types of NCM materials, such as NCM111, NCM523, NCM622, and NCM712, may also undergo similar reduction processes.

By controlling the reduction conditions—including the choice of reducing agents, gas phase (such as N₂, Ar, O₂, CO₂, and combinations thereof), temperature (e.g., 100° C. to 900° C.), time (e.g., 0.1 to 24 hours) and the use of additives such as sodium carbonate (Na₂CO₃), sodium bicarbonate (NaHCO₃), potassium carbonate (K₂CO₃), and potassium bicarbonate (KHCO₃), the process reduces both LCO and NCM materials from higher oxidation states (Co³⁺, Ni³⁺) to lower oxidation states (Co²⁺, Ni²⁺) without fully reducing them to metallic states. This reduction step also alters the morphology and particle size, thereby increasing the surface area of the particles. Furthermore, additives are used to control the release of toxic gases, such as hydrogen fluoride (HF). A critical morphology change is the reduction in particle size, from the micron to the nanometer scale.

At 130, a leaching process may be performed on the pretreated cathode materials to produce a leachate. The leaching process may involve dissolving the pretreated cathode materials in an aqueous solution of an organic acid, such as formic acid, citric acid, and combinations thereof.

By controlling the leaching conditions—including the choice of an aqueous solution of an organic acid, the concentration of the organic acid solution (e.g., 0.1M to 5M), leaching temperature (e.g., 20° C. to 100° C.), leaching time (e.g., 0.1 to 24 hours), and the use of additives such as hydrogen peroxide (1% to 25% by volume), the efficiency of metal extraction may be optimized.

As an example, a 2 M solution of formic acid (or another organic acid) may be prepared in deionized water. The pretreated cathode material is added to the solution, which is then heated to 70° C. and stirred for one hour. The addition of hydrogen peroxide (approximately 5% by volume) may be used to further enhance the leaching rate for untreated materials, particularly in embodiments in which the raw cathode materials include NCM. As a result of this leaching process, a solution containing dissolved metal ions, referred to as the leachate, is produced.

At 140, recycled cathode materials may be recovered from the leachate. The recycled cathode materials may include, for example, cobalt, nickel, etc. The recovery of the cathode materials from the leachate may involve, for example, adding oxalic acid to precipitate cobalt oxalate and nickel oxalate. These precipitates are insoluble in water and can be readily separated from the solution by filtration. The remaining solution may then be regenerated and recycled for use in subsequent leaching steps.

At 150, the acid solution may be recycled from the leachate for repeated use in subsequent leaching processes. The acid solution may be regenerated by adjusting the pH after the precipitation step, thereby allowing the same solution to be reused in later leaching cycles. This closed-loop system minimizes waste generation and enhances the overall sustainability of the process.

FIG. 2 illustrates a diagram depicting the remaining mass of cathode material following leaching with various acids. The diagram provides a comparative analysis of the dissolution effectiveness of each acid under controlled experimental parameters, including temperature, leaching duration, and acid molarity.

The diagram illustrates the remaining mass of pretreated cathode material following an organic acid leaching process using various acids. The leaching process was conducted at a temperature of 70° C. for a duration of two hours, with a solid-to-liquid ratio of 0.5 g of cathode material per 50 mL of solution and an acid molarity of 2 M. The results indicate that sulfuric acid, citric acid, tartaric acid, glycolic acid, and formic acid were highly effective in dissolving the cathode material, leaving no remaining mass (0 g). In contrast, acetic acid partially dissolved the material, leaving a remaining mass of approximately 0.27 g. Lactic acid was slightly less effective, leaving about 0.36 g of cathode material. Salicylic acid and oxalic acid were the least effective, leaving approximately 0.5 g of material, indicating minimal dissolution. This comparison demonstrates the varying effectiveness of different organic acids in dissolving cathode materials under identical experimental conditions.

FIG. 3 illustrates a plot showing the leaching time of reduced lithium cobalt oxide (LCO) using various acid solutions in accordance with some embodiments of the present disclosure. The leaching experiments were performed at a temperature of 70° C. with a total leaching duration of one hour, a solid-to-liquid ratio of 1 g of LCO per 50 mL of solution, and an acid molarity of 2 M.

The results indicate that sulfuric acid and formic acid exhibited comparable reaction kinetics, each completing the leaching process in approximately seven minutes. The combination of formic and citric acids required slightly more time, completing the leaching in approximately nine minutes. Leaching with citric acid alone required approximately fourteen minutes, while the combination of citric and glycolic acids also completed the leaching process within fourteen minutes.

As demonstrated by the plot, sulfuric acid and formic acid achieve faster leaching rates compared with other acid systems under identical experimental conditions, thereby confirming their higher leaching efficiency.

FIG. 4 illustrates a diagram depicting the leaching time required for the complete dissolution of reduced nickel-cobalt-manganese (NCM) materials using various acid solutions. The leaching experiments were performed under controlled conditions, including a temperature of 70° C., a total leaching duration of one hour, a solid-to-liquid ratio of 1 g of NCM per 50 mL of solution, and an acid molarity of 2 M.

The results indicate that sulfuric acid and formic acid exhibited comparable reaction kinetics, completing the leaching process in approximately seven and ten minutes, respectively. The combination of formic and citric acids required slightly more time, completing the leaching in approximately fifteen minutes. In contrast, the combination of formic and oxalic acids required substantially more time, completing the leaching process in approximately forty-two minutes.

This plot demonstrates the relative efficiency of sulfuric acid and formic acid in facilitating the rapid leaching of reduced NCM materials compared with other acid systems. In particular, the formic and oxalic acid combination exhibited significantly slower leaching kinetics under identical experimental conditions.

FIG. 5 illustrates a plot comparing the effectiveness of formic acid and sulfuric acid in leaching raw nickel-cobalt-manganese (NCM) materials in accordance with some embodiments of the present disclosure. The leaching experiments were performed under controlled conditions at a temperature of 70° C., with a total leaching duration of one hour, a solid-to-liquid ratio of 1 g of raw NCM per 50 mL of acid solution, and an acid molarity of 2 M.

The undissolved mass of raw NCM material was measured after completion of the leaching process to determine the extent of dissolution. The results indicate that a greater portion of the NCM material reacted and dissolved in formic acid compared with sulfuric acid, demonstrating that formic acid exhibited superior leaching effectiveness under these experimental conditions.

This plot demonstrates the enhanced performance of formic acid relative to sulfuric acid in dissolving raw NCM materials, thereby confirming its potential for achieving higher leaching efficiency in similar recycling processes.

FIG. 6 illustrates the X-ray Photoelectron Spectroscopy (XPS) analysis of lithium cobalt oxide (LCO), comparing the spectra of the raw and reduced forms of the material. The line 605 represents the XPS spectrum of raw LCO, while the line 610 corresponds to the spectrum of reduced LCO.

The analysis demonstrates the migration of lithium (Li) from the bulk to the surface of the LCO after the reduction process. The Co peaks in the spectrum are clearly visible, with the reduced LCO (line 610) showing a shift in binding energy compared to the raw LCO (line 605). Oxygen (O) peaks are also observed, and the changes in the spectrum suggest surface alterations due to the reduction process.

This XPS data indicates significant changes in the chemical states of cobalt and lithium ion LCO following reduction, with lithium migration to the surface being a key observation.

FIG. 7 illustrates the X-ray Photoelectron Spectroscopy (XPS) analysis of nickel-cobalt-manganese (NCM) material, comparing the spectra of raw NCM (line 706) and reduced NCM (line 710) in accordance with some embodiments of the present disclosure. The reduction process results in the transformation of Co³⁺ and Ni³⁺ into Co²⁺ and Ni²⁺, respectively. Additionally, the analysis reveals the migration of lithium (Li) from the bulk to the surface of the material following the reduction step.

In the spectrum, the distinct peaks corresponding to nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), and oxygen (O) are clearly visible. Notably, there are changes in the binding energies and intensity of these peaks after the reduction process, as shown by the differences between the red and green lines. These changes indicate alterations in the chemical states of the elements and the redistribution of lithium on the surface of the material.

This XPS analysis provides insight into the structural changes occurring in NCM during the reduction process, specifically highlighting the reduction of metal ions and the migration of lithium to the surface.

FIGS. 8A, 8B, 9A, and 9B illustrate Scanning Electron Microscopy (SEM) images depicting the surface morphology of raw and reduced lithium cobalt oxide (LCO) and nickel-cobalt-manganese (NCM) materials. The SEM analysis confirms a substantial reduction in particle size, from the micron scale to the nanometer scale, following the reduction process..

FIGS. 8A and 8B present SEM images of LCO materials, where FIG. 8A depicts raw LCO and FIG. 8B depicts reduced LCO.

FIGS. 9A and 9B present SEM images of NCM materials, where FIG. 9A depicts raw NCM and FIG. 9B depicts reduced NCM. As illustrated, the reduction process significantly decreases particle size and correspondingly increases the surface area available for subsequent leaching reactions.

FIG. 10 is a flow diagram illustrating an example process 1000 for battery cathode materials recycling in accordance with some embodiments of the present disclosure.

Process 1000 may begin with providing black mass 1010, which may include cathode materials such as lithium cobalt oxide (LCO), nickel-cobalt-manganese oxide (NCM), lithium manganese oxide (LMO), or other similar compositions obtained from spent lithium-ion batteries.

The black mass 1010 may undergo a reduction process utilizing carbon sources 1020, where carbonaceous materials, such as glucose, graphite, or other organic carbon compounds, are used to chemically reduce metal oxides present in the black mass. The reduction process may convert higher oxidation states of transition metals (e.g., Co³⁺, Ni³⁺) into lower oxidation states (e.g., Co²⁺, Ni²⁺), enhancing their solubility in subsequent processing steps.

Following the reduction process, the treated materials may undergo a leaching step 1030 employing one or more organic acids or mixtures thereof. In some embodiments, aqueous solutions of organic acids such as formic acid, citric acid, or combinations thereof may be used to dissolve the reduced cathode materials, generating a leachate solution containing dissolved metal ions and insoluble residues.

The leachate solution may be subsequently undergo a filtration process 1040 to separate the insoluble solid wastes 1050 from the liquid phase. The solid residues may include undissolved carbon and other inert compounds, which may be removed from the system for appropriate disposal or treatment.

The resulting filtrate solutions 1060 may contain dissolved metals and may undergo a precipitation process at 1070. In some embodiments, oxalic acid may be introduced into the filtrate to selectively precipitate metal oxalates, including nickel oxalate, cobalt oxalate, and manganese oxalate.

The resulting suspension may then undergo a filtration process at 1080 to separate the solid precipitates from the liquid phase. The solid fraction may include Ni, Co, and Mn oxalates 1090, which may subsequently be processed to recover pure metal compounds for reuse in battery manufacturing.

The filtrate obtained following metal precipitation may form the organic acid solutions 1100. The solution may be recycled and regenerated 1110 for reuse in the leaching step, thereby establishing a closed-loop system that minimizes chemical waste and enhances overall process sustainability.

For simplicity of explanation, the methods of this disclosure are depicted and described as a series of acts. However, acts in accordance with this disclosure can occur in various orders and/or concurrently, and with other acts not presented and described herein. Furthermore, not all illustrated acts may be required to implement the methods in accordance with the disclosed subject matter. In addition, those skilled in the art will understand and appreciate that the methods could alternatively be represented as a series of interrelated states via a state diagram or events.

The terms “approximately,” “about,” and “substantially” may be used to mean within ±20% of a target dimension in some embodiments, within ±10% of a target dimension in some embodiments, within ±5% of a target dimension in some embodiments, and yet within ±2% in some embodiments. The terms “approximately” and “about” may include the target dimension.

In the foregoing description, numerous details are set forth. It will be apparent, however, that the disclosure may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the disclosure.

The terms “first,” “second,” “third,” “fourth,” etc. as used herein are meant as labels to distinguish among different elements and may not necessarily have an ordinal meaning according to their numerical designation.

The words “example” or “exemplary” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words “example” or “exemplary” is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X includes A or B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Reference throughout this specification to “an implementation” or “one implementation” means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least one implementation. Thus, the appearances of the phrase “an implementation” or “one implementation” in various places throughout this specification are not necessarily all referring to the same implementation.

Whereas many alterations and modifications of the disclosure will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description, it is to be understood that any particular embodiment shown and described by way of illustration is in no way intended to be considered limiting. Therefore, references to details of various embodiments are not intended to limit the scope of the claims, which in themselves recite only those features regarded as the disclosure.