Method and system for producing precursor material from black mass of spent lithium-ion batteries

Abstract

The method (100) for selective lithium extraction from spent lithium-ion batteries, the method includes preparing a black mass (302) from the spent lithium-ion batteries, roasting the black mass at a predefined elevated temperature in an inert gas chamber comprising argon gas and carbon to obtain a roasted black mass, and 5 leaching the roasted black mass with a defined amount of water forming a predefined pulp density to obtain a leach liquor

Description

[0001] METHOD AND SYSTEM FOR PRODUCING PRECURSOR MATERIAE FROM BEACK MASS OF SPENT LITHIUM-ION BATTERIES

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a field of battery recycling technology. Moreover, the present disclosure relates to a method and system for selective lithium extraction from spent lithium-ion batteries.

[0004] BACKGROUND

[0005] Generally, lithium-ion batteries (LIBs) have revolutionized the energy storage landscape since their commercial introduction in 1990. The LIBs are renowned for exceptional performance characteristics, including efficient charging and discharging capabilities, high working voltage, impressive energy density, lightweight construction, prolonged cycle life, and enhanced safety features. As a result, the LIBs have become integral to various industries, finding widespread application in new energy vehicles, portable electronics, communication devices, and solar energy systems. The LIB market is projected to reach an astounding $999.8 billion by 2025, with an estimated shipment volume of 439.32 billion kilowatt-hours.

[0006] However, the exponential increase in LIB disposal after their typical 3-5 years operational lifespan presents a formidable environmental and resource management challenge. Spent LIBs contain a plethora of valuable materials such as lithium, cobalt, nickel, manganese, aluminium, and copper, as well as potentially harmful elements including heavy metals and toxic organic electrolytes. The effective recovery and eco-friendly treatment of such resources have emerged as pressing priorities to mitigate environmental pollution and promote sustainable resource management practices. Currently, certain attempts have been made to recycle LIBs, primarily focusing on hydrometallurgical and pyrometallurgical processes. Hydrometallurgy offers notable metal recovery rates but relies on substantial quantities of strong acids, bases, and reducing agents. Such attempts often result in high operational costs and generate wastewater laden with acidic and organic contaminants, leading to secondary pollution of atmospheric and aquatic environments. On the other hand, traditional pyrometallurgical incineration methods operate at temperatures as high as 800-1000°C, consuming substantial energy and posing significant risks of generating toxic gases such as chlorides and dioxins. Moreover, the high incineration temperatures contribute to considerable lithium evaporation losses, further diminishing resource recovery efficiency.

[0007] Thus, there exists a technical problem in developing a sustainable solution for recycling spent lithium-ion batteries and improving the efficiency of valuable material recovery, particularly lithium, that addresses the environmental impact of LIB disposal while maximizing resource recovery and minimizing costs.

[0008] Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with the conventional method and system for recycling the LIBs.

[0009] SUMMARY

[0010] The present disclosure provides a method and system for selective lithium extraction from spent lithium-ion batteries. The present disclosure provides a solution to the technical problem of how to recycle spent lithium-ion batteries and improve the efficiency of valuable material recovery, particularly lithium. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in the prior art and provide an improved method and system for selective lithium extraction from spent lithium-ion batteries. One or more objectives of the present disclosure are achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.

[0011] In one aspect, the present disclosure provides a method for selective lithium extraction from spent lithium-ion batteries that includes preparing a black mass from the spent lithium-ion batteries, roasting the black mass at a predefined elevated temperature in an inert gas chamber comprising argon gas and carbon to obtain a roasted black mass and leaching the roasted black mass with a defined amount of water forming a predefined pulp density to obtain a leach liquor.

[0012] Advantageously, the method is used for selective lithium extraction from spent lithium-ion batteries. By roasting the black mass in an inert atmosphere enriched with argon gas and carbon, the method is used to effectively prevent oxidation and degradation of the sensitive cathode materials, ensuring the preservation of valuable lithium components and enhancing the overall purity of the extracted lithium. Furthermore, the presence of argon gas during roasting facilitates the removal of volatile impurities, improving the quality of the recovered lithium in order to ensure that the final lithium product is suitable for reuse in battery manufacturing with minimal need for additional purification. The roasting process, combined with carbon, promotes the reduction of lithium compounds, maximizing the extraction efficiency and resulting in a higher yield of lithium from the spent batteries compared to conventional methods. Additionally, the defined water leaching step, with a controlled pulp density, allows for selective extraction of lithium ions while leaving other metals and impurities behind that enhances the recovery rate of lithium and ensures that the leach liquor contains a high concentration of lithium with minimal contamination. Furthermore, the utilization of an inert atmosphere and controlled roasting conditions minimizes energy consumption and emissions compared to traditional methods, such as high-temperature pyrolysis or acid leaching. Additionally, the method reduces the generation of hazardous waste, contributing to a more sustainable recycling approach with reduced reliance on harsh chemicals and lower energy requirements, which can lead to cost savings in both operational and environmental management. Therefore, the method provides a technically advanced approach to lithium extraction, combining enhanced purity, effective impurity removal, optimized recovery, and reduced environmental impact, making it a significant improvement over traditional extraction method.

[0013] In another aspect, the present disclosure provides a system for selective lithium extraction from spent lithium-ion batteries that includes a preparation unit configured to prepare a black mass from the spent lithium-ion batteries, a roasting unit configured to roast the black mass at an elevated temperature in an inert atmosphere comprising argon gas and carbon to obtain a roasted black mass, a leaching unit configured to leach the roasted black mass with water at a predefined pulp density to obtain a leach liquor, a first filtration unit configured to filter the leach liquor to separate a lithium-rich solution from solid residues, a concentration unit configured to concentrate the lithium-rich solution through heating to achieve a lithium concentration of up to 20 grams per litre, a precipitation unit configured to precipitate lithium carbonate from the concentrated solution by purging with carbon dioxide gas and a second filtration unit configured to filter the precipitated lithium carbonate to obtain a high-purity lithium carbonate product.

[0014] The system achieves all the advantages and technical effects of the method of the present disclosure.

[0015] It is to be appreciated that all the aforementioned implementation forms can be combined. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

[0016] Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

[0019] Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

[0020] FIG. 1 is a flowchart depicting a method for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure; FIG. 2 is a block diagram illustrating a system for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure;

[0021] FIG. 3 is a diagram illustrating an exemplary implementation of the method for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure; and

[0022] FIG. 4 is a diagram illustrating a sequential flow of the method for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure.

[0023] DETAILED DESCRIPTION OF EMBODIMENTS

[0024] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practising the present disclosure are also possible.

[0025] FIG. 1 is a flowchart depicting a method for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown a flowchart of a method 100, i.e., the method 100 where all steps are implemented in a system for selective lithium extraction from spent lithium-ion batteries. There is provided the method 100 for selective lithium extraction from spent lithium-ion batteries. The method 100 includes the steps 102 to 106.

[0026] At step 102, the method 100 comprises preparing a black mass from the spent lithium-ion batteries. The black mass contains cathode and anode materials obtained from the spent lithium-ion batteries. In an embodiment, the black mass refers to a powdered substance obtained by crushing the spent lithium-ion batteries using a mechanical process, such as lithium, cobalt, nickel, and other components commonly found in battery materials. The spent lithium-ion batteries comprise Lithium-ion batteries of different compositions including Lithium Iron Phosphate (LFP), Lithium Cobalt Oxide (LCO), and Lithium Titanium Oxide (LTO). The aforementioned mechanical process effectively breaks down the spent lithium-ion batteries into the black mass, which is further processed for the selective lithium extraction from spent lithium-ion batteries.

[0027] At step 104, the method 100 comprises roasting the black mass at a predefined elevated temperature in an inert gas chamber comprising argon gas and carbon to obtain a roasted black mass. In other words, the black mass, containing cathode and anode materials from spent lithium-ion batteries, is subjected to the roasting process. The roasting is conducted in a tubular furnace under controlled temperature, in the presence of argon gas and excess carbon. The use of an inert atmosphere with argon gas serves to prevent oxidation and degradation of the sensitive cathode material, ensuring the preservation of valuable components specifically lithium. The presence of argon gas also aids in the removal of volatile impurities, enhancing the purity of the lithium to be recovered. Additionally, the introduction of carbon facilitates the reduction of lithium compounds, promoting efficient lithium recovery. The roasting process ensures maximum utilization of the lithium present in the spent lithium-ion batteries, optimizing resource efficiency and reducing waste. The roasting step enables breaking down of the complex lithium compounds in the black mass, making the lithium compounds more amenable to subsequent extraction processes.

[0028] In accordance with an embodiment, roasting the black mass is performed at a temperature ranging from 700°C to 800°C for a time duration ranging from 60 to 120 minutes. In other words, the roasting process is carried out within a specific temperature range and time duration to optimize lithium extraction. The temperature is maintained between 700°C and 800°C. The duration of roasting ranges from 60 to 120 minutes. The temperature range and duration are critical for effectively breaking down the lithium compounds without causing excessive volatilization or unwanted side reactions. The controlled conditions of temperature and time duration ensure efficient conversion of lithium compounds into forms that are more easily extractable in subsequent steps. By maintaining the temperature and the time duration, the roasting process achieves a balance between maximizing lithium recovery and minimizing energy consumption, contributing to both efficiency and sustainability of the method 100.

[0029] At step 106, the method 100 comprises leaching the roasted black mass with a defined amount of water forming a predefined pulp density to obtain a leach liquor. In other words, following the roasting process, the roasted black mass undergoes a water-leaching step. The water-leaching step involves mixing the roasted black mass with a specific amount of water to create a leach liquor (in form of slurry) with a predetermined pulp density. Water leaching is chosen for its ability to selectively dissolve lithium while leaving other impurities behind. The waterleaching step is crucial for separating the lithium from the other components of the roasted black mass. The use of water as a leaching agent is environmentally friendly and cost-effective compared to traditional acid leaching methods. The resulting leach liquor contains the dissolved lithium, which can then be further processed to obtain high-purity lithium compounds. The water-leaching step is a key factor in achieving high lithium recovery rates while minimizing the extraction of unwanted impurities.

[0030] In accordance with an embodiment, leaching the roasted black mass is performed at a temperature ranging from 20°C to 30°C for a time duration ranging from 4 to 8 hours. In other words, the water-leaching step is conducted under a specific temperature range and time duration to optimize lithium extraction. The specific temperature range is maintained between 20°C and 30°C. The time duration ranges from 4 to 8 hours. The temperature range and time duration are carefully selected to maximize lithium dissolution while minimizing the dissolution of unwanted impurities. The relatively low-temperature range (20°C - 30°C) helps to reduce energy consumption and prevents the dissolution of certain impurities that might become more soluble at higher temperatures. The extended leaching time duration ensures thorough contact between the water and the roasted black mass, allowing for efficient lithium extraction. The temperature range and time duration contribute to achieving high lithium recovery rates while maintaining the purity of the leach liquor.

[0031] In accordance with an embodiment, the predefined pulp density for leaching ranges from 5 % to 15 %. In other words, the water-leaching step is carried out at a specific pulp density, which is the ratio of solid material to liquid in the slurry. The pulp density is maintained between 5% and 15%. The range of pulp density enables achieving optimal lithium extraction efficiency. A higher pulp density allows for processing more material in a given volume, increasing throughput. However, the predefined pulp density is balanced against the need for sufficient liquid to ensure effective dissolution and separation of lithium from a solid matrix. The pulp density maintained between 5% and 15% strikes a balance between the liquid and the solid matrix, allowing for efficient lithium extraction while maintaining practical processing volumes. The optimized pulp density contributes to the ability of the method 100 to achieve high lithium recovery rates while minimizing water usage and processing time.

[0032] In accordance with an embodiment, the method 100 further comprises filtering the leach liquor to separate a lithium-rich solution from solid residues. In other words, the water-leaching step is followed by a filtration step, the leach liquor undergoes the filtration step to separate dissolved lithium from any remaining solid residues (impurities). The filtration step involves passing the leach liquor through a filter medium, which retains the solid particles while allowing the lithium-rich solution to pass through. The solid particles may include but are not limited to, graphite and other carbon particles. The filtration step enables removing any undissolved particles or impurities that may have remained after the water-leaching step. By separating the lithium-rich solution from the solid residues, the filtration step ensures that the subsequent steps can be carried out more efficiently. The filtration step contributes to the overall purity of the final lithium product by removing potential contaminants early in the method 100.

[0033] In accordance with an embodiment, the method 100 further comprises concentrating the lithium-rich solution through heating to achieve a lithium concentration of up to 20 grams per litre. In other words, the filtration step is followed by a concentration step. The lithium-rich solution undergoes the concentration step. The concentration step involves heating the lithium-rich solution to evaporate excess water, thereby increasing the concentration of lithium ions. The lithium-rich solution is concentrated until it reaches a lithium concentration of up to 20 grams per liter (gpl). By reducing the volume of the lithium-rich solution and increasing the lithium concentration, less energy and resources are required in subsequent steps. Additionally, the higher concentration of lithium ions promotes more efficient and complete precipitation of lithium carbonate in the subsequent steps of the method 100. The concentration step enables optimizing the overall yield and purity of the final lithium product. In accordance with an embodiment, the method 100 further comprises precipitating lithium carbonate from the concentrated solution by purging with carbon dioxide gas. In other words, the concentration step is followed by a precipitation step. The lithium-rich solution undergoes the precipitation step to convert the dissolved lithium ions into solid lithium carbonate. The precipitation step is achieved by purging the concentrated solution with carbon dioxide (CO2) gas. The CO2 reacts with the lithium ions in the lithium-rich solution to form lithium carbonate, which precipitates out of the lithium-rich solution as a solid. The precipitation step is highly efficient and selective for lithium, as other potential impurities typically do not form insoluble carbonates under such conditions. The use of CO2 gas for the precipitation step is environmentally friendly and cost-effective compared to other precipitation methods. Moreover, the precipitation step utilizes the CO2 produced during the roasting step, creating a closed-loop system that enhances the overall sustainability of the lithium extraction method 100. The precipitation step enables converting the extracted lithium into a solid form (lithium carbonate) that is directly usable in battery manufacturing.

[0034] In accordance with an embodiment, the method 100 further comprises capturing and repurposing the carbon dioxide gas released during roasting for the precipitation of lithium carbonate, thereby creating a closed-loop system. The method 100 involves capturing and repurposing the carbon dioxide (CO2) gas released during the roasting step. The CO2 is then utilized in the precipitation step of the method 100 for the precipitation of lithium carbonate. The roasting step, conducted at high temperatures, results in the decomposition of some carbonate compounds present in the black mass, releasing CO2. Instead of allowing the CO2 gas to escape, it is captured using appropriate gas collection systems. The captured CO2 is then stored and later used in the precipitation step, where it is purged through the concentrated lithium-rich solution to form lithium carbonate, creating a closed- loop system within the lithium extraction process. By repurposing the CO2, the method 100 reduces the need for external sources of CO2 for precipitation, thereby enhancing the overall efficiency and sustainability of the method 100. The closed- loop system not only minimizes greenhouse gas emissions but also maximizes resource utilization, aligning the method 100 with circular economy principles and demonstrating a commitment to environmental stewardship in lithium recycling.

[0035] In accordance with an embodiment, the method 100 further comprises filtering the precipitated lithium carbonate to obtain a high-purity lithium carbonate product. The precipitated lithium carbonate is passed through a filter, which retains the solid lithium carbonate while allowing the liquid to pass through. The filtered lithium carbonate is then collected as a final product. The filtration enables isolating the high-purity lithium carbonate from any remaining impurities. The filtration ensures that the final product meets the high purity standards required for use in battery manufacturing and other applications. By effectively separating the solid lithium carbonate from the liquid, the filtration contributes to the overall purity and quality of the final lithium carbonate product.

[0036] In accordance with an embodiment, the high-purity lithium carbonate product has a purity of at least 99% and the method 100 achieves a lithium recovery rate of at least 95%. In an implementation, the method 100 produces the high-purity lithium carbonate product with a purity of at least 99%. The high level of purity is achieved through the carefully controlled processes of the roasting step, and leaching step along with the filtration step, the concentration step, and the precipitation step. The high lithium recovery rates are attained through optimized roasting conditions, selective water leaching, and efficient precipitation process. The high purity and recovery rates enable the reuse of lithium in lithium-ion battery manufacturing, as they ensure that the recycled lithium meets or exceeds the quality standards of primary lithium sources. The high efficiency in both purity and recovery rate demonstrates the effectiveness of the method 100 while dealing with the challenges of lithium recycling from spent lithium-ion batteries, contributing significantly to resource conservation and sustainable battery production.

[0037] In accordance with an embodiment, the method 100 further comprises analyzing the black mass, the roasted black mass, and the lithium-rich solution using Inductively Coupled Plasma (ICP) analysis to determine chemical compositions of the black mass, the roasted black mass, and the lithium-rich solution. The method 100 comprises multiple stages of chemical analysis using Inductively Coupled Plasma (ICP) technique. ICP analysis is performed on the black mass before roasting, on the roasted black mass before leaching, and on the lithium-rich solution obtained after leaching. In the ICP analysis, the sample is subjected to high temperatures in an argon plasma, causing the elements present to emit characteristic wavelengths of light. The emissions of wavelengths of light are then measured to quantify the concentrations of various elements in the sample. For the initial black mass, ICP analysis reveals the starting composition, including the concentrations of lithium, aluminium, iron, copper, nickel, cobalt, and manganese. After roasting, another ICP analysis is conducted to assess changes in chemical composition, confirming the effectiveness of the roasting process in preparing the material for lithium extraction. Finally, ICP analysis of the lithium-rich solution after leaching provides crucial data on the efficiency of lithium extraction and the levels of any remaining impurities. The multiple stages of ICP analysis are useful for monitoring and optimizing each step of the lithium extraction method 100, ensuring high purity and efficiency in the final lithium carbonate product.

[0038] FIG. 2 is a block diagram illustrating a system for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure. With reference to FIG. 2, there is shown a diagram 200 illustrating a system 202 for selective lithium extraction from spent lithium-ion batteries. The system 202 includes a preparation unit 204, a roasting unit 206, a leaching unit 208, a concentration unit 210, precipitation unit 212, a first filtration unit 214, a second filtration unit 216, a programmable logic controller 218, and an analysis unit 220.

[0039] In operation, the system 202 for selective lithium extraction from spent lithium-ion batteries includes the preparation unit 204 that is configured to prepare a black mass from the spent lithium-ion batteries. Furthermore, the system 202 includes the roasting unit 206 configured to roast the black mass at an elevated temperature in an inert atmosphere comprising argon gas and carbon to obtain a roasted black mass. Moreover, the system 202 includes the leaching unit 208 configured to leach the roasted black mass with water at a predefined pulp density to obtain a leach liquor. Furthermore, the system 202 includes the first filtration unit 214 configured to filter the leach liquor to separate a lithium-rich solution from solid residues. Moreover, the system 202 includes the concentration unit 210 configured to concentrate the lithium-rich solution through heating to achieve a lithium concentration of up to 20 grams per litre and the precipitation unit 212 configured to precipitate lithium carbonate from the concentrated solution by purging with carbon dioxide gas. Furthermore, the system 202 includes the second filtration unit 216 configured to filter the precipitated lithium carbonate to obtain a high-purity lithium carbonate product.

[0040] There is provided the system 202 for selective lithium extraction from spent lithium-ion batteries, the system 202 includes the preparation unit 204 configured to prepare a black mass from the spent lithium-ion batteries. The preparation unit 204 is configured to dismantle the spent lithium-ion batteries to extract valuable components, particularly the cathode and anode materials. The preparation unit 204 is further configured to the extract active materials that contain lithium, that is the primary target for extraction. Thus, by effectively preparing a consistent black mass, the system 202 ensures that subsequent processing steps can be optimized.

[0041] Furthermore, the system 202 includes the roasting unit 206 configured to roast the black mass at an elevated temperature in an inert atmosphere comprising argon gas and carbon to obtain a roasted black mass. The extracted back mass is roasted to break down the complex lithium compounds present in the black mass into simpler forms, which can be more easily leached. By using the inert atmosphere with argon gas, the roasting unit 206 is configured to prevent the oxidation and degradation of the sensitive cathode materials present in the black mass, thereby preserving the valuable lithium content. In an implementation, the roasting process may involve the presence of carbon, which facilitates the reduction of lithium compounds, thereby enhancing the quality and yield of lithium extraction. Furthermore, the system 202 includes the leaching unit 208 configured to leach the roasted black mass with water at a predefined pulp density to obtain a leach liquor. The selective leaching of the roasted black mass with water dissolves lithium-ions from the roasted black mass, leaving behind other impurities. Further, the selective leaching of the roasted black mass is achieved by controlling the pulp density of the solution made by dissolving water into the roasted black mass. Therefore, the leaching process implemented by the leaching unit 208 allows for the efficient extraction of lithium by converting the roasted black mass into a solution, which is often called leached liquor.

[0042] Furthermore, the system 202 includes the first filtration unit 214 configured to filter the leach liquor to separate a lithium-rich solution from solid residues. The filtration of the leach liquor is necessary to remove any undissolved solid particles from the leach liquor, ensuring that the extracted lithium-rich solution is free from impurities. After the roasted black mass undergoes water leaching, the resultant leach liquor contains dissolved lithium ions along with various solid residues and impurities. Such impurities and solid residue is filtered by the first filtration unit 214. In an implementation, the first filtration unit 214 may include but not limited to a filtration medium, such as a filter press or a vacuum filter, designed to capture fine solid particles while allowing the leach liquor to pass through. Additionally, the first filtration unit 214 may operate under controlled conditions, such as specific pressure and temperature settings, to optimize the separation of solids from the leach liquor and provide the lithium-rich solution.

[0043] Furthermore, the system 202 includes the concentration unit 210 configured to concentrate the lithium-rich solution through heating to achieve a lithium concentration of up to 20 grams per litre. The concentration unit 210 operates by applying heat to the lithium-rich solution, causing the water present in the lithium- rich solution to evaporate, thereby reducing the volume of the lithium-rich solution while increasing the concentration of dissolved lithium ions. Further, by achieving a lithium concentration of up to 20 grams per liter, the concentration unit 210 significantly improves the efficiency of the subsequent lithium carbonate precipitation process.

[0044] Furthermore, the system 202 includes the precipitation unit 212 configured to precipitate lithium carbonate from the concentrated solution by purging with carbon dioxide gas. The precipitation unit 212 operates by introducing carbon dioxide (CO2) into the concentrated lithium-rich solution. Further, when the CO2 is purged introduced in the lithium-rich solution, the CO2 reacts with the lithium ions to form lithium carbonate (Li2CO3) by a chemical reaction, which can be represented by the following equation:

[0045] 2Li++ CO2+ H2O Li2CO3(J,) + 2H+

[0046] Moreover, as the lithium carbonate (Li2CO3) forms, the lithium carbonate precipitates out of the lithium-rich solution as a solid, which can then be separated from the remaining liquid.

[0047] Furthermore, the system 202 includes the second filtration unit 216 configured to filter the precipitated lithium carbonate to obtain a high-purity lithium carbonate product. The concentration process involves evaporating some of the water from the lithium-rich solution, thereby increasing the lithium-ion concentration. Further, by achieving a high concentration of lithium ions, the system 202 ensures that the subsequent precipitation process is effective and yields a high-purity product.

[0048] In accordance with an embodiment, the system 202 further includes the analysis unit 220 configured to perform Inductively Coupled Plasma (ICP) analysis on the black mass, the roasted black mass, and the lithium-rich solution to determine their chemical compositions, and the Programmable Logic Controller (PLC) 218 operatively coupled to the roasting unit 206, the leaching unit 208, the concentration unit 210, the precipitation unit 212, the first filtration unit 214, the second filtration unit 216, and the analysis unit 220. Furthermore, the PLC 218 is configured to adjust operational parameters based on the ICP analysis results to optimize the selective lithium extraction. The PLC 218 is programmed to receive the data from the ICP analysis and interpret the results. Further, based on the received analysis, the PLC 218 is configured to adjust parameters such as temperature, pressure, leaching time, and gas flow rates in the roasting, leaching, concentration, and precipitation. In an implementation, the adjustments in the parameters are made automatically and in real time, ensuring that the process remains within optimal operating conditions. In an example, if the ICP analysis indicates a lower-than- expected lithium concentration in the leach liquor, the PLC is configured to increase the leaching time or adjust the pulp density to improve lithium recovery.

[0049] FIG. 3 is a diagram illustrating an exemplary implementation of the method for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure. With the reference to FIG. 3, there is shown a diagram 300, that includes the black mass 302, the cobalt oxide (CoO) 308, and the lithium carbonate (LiiCOs).

[0050] In an implementation, the diagram 300 illustrates an implementation of the method 100 for selective lithium extraction from spent lithium-ion batteries begins with the black mass 302 being fed into a carbothermal reduction roasting unit 304. In an implementation, the black mass 302 may include lithium cobalt oxide and graphite. The black mass 302 is further subjected to the high temperature in an inert atmosphere, typically containing argon gas and carbon in the carbothermal reduction roasting unit 304. The carbothermal reduction roasting process converts the black mass into cobalt oxide (CoO) and lithium-rich compounds. Furthermore, the roasted black mass is then transferred to an aqueous solution separation unit 306. The separation unit 306 is configured to mix the roasted black mass with water at a predefined pulp density, leading to the leaching of lithium compounds into the solution, forming a lithium-rich liquor. In an implementation, the lithium-liquor contains some solid residues, which include cobalt oxide, are separated from the lithium-rich liquor. Furthermore, the solid residues, cobalt oxide (CoO), are collected for further use or disposal. The lithium-rich leach liquor, on the other hand, is subjected to further processing to recover lithium. The final products of the method for selective lithium extraction from spent lithium-ion batteries are high- purity cobalt oxide (CoO) and lithium carbonate (Li2CO3), which are separated and collected separately.

[0051] Therefore, by roasting the black mass in an inert atmosphere enriched with argon gas and carbon, the method 100 is used to effectively prevent oxidation and degradation of the sensitive cathode materials, ensuring the preservation of valuable lithium components, and enhancing the overall purity of the extracted lithium. Furthermore, the presence of argon gas during roasting facilitates the removal of volatile impurities, improving the quality of the recovered lithium in order to ensure that the final lithium product is suitable for reuse in battery manufacturing with minimal need for additional purification. The roasting process, combined with carbon, promotes the reduction of lithium compounds, maximizing the extraction efficiency and resulting in a higher yield of lithium from the spent batteries compared to conventional methods. Additionally, the defined water leaching step, with a controlled pulp density, allows for selective extraction of lithium ions while leaving other metals and impurities behind that enhances the recovery rate of lithium and ensures that the leach liquor contains a high concentration of lithium with minimal contamination. Furthermore, the utilization of an inert atmosphere and controlled roasting conditions minimizes energy consumption and emissions compared to traditional methods, such as high-temperature pyrolysis or acid leaching. Additionally, the implemented method reduces the generation of hazardous waste, contributing to a more sustainable recycling approach with reduced reliance on harsh chemicals and lower energy requirements, which can lead to cost savings in both operational and environmental management.

[0052] FIG. 4 is a diagram illustrating a sequential flow of the method for selective lithium extraction from spent lithium-ion batteries, in accordance with an embodiment of the present disclosure. With the reference to FIG. 4, there is shown a flowchart 400 for the sequential flow of the selective lithium extraction from spent lithium-ion batteries. The flowchart 400 includes the operations 402 to 414. At operation 402, the spent lithium-ion batteries are processed to prepare a black mass. The preparation of the black involves dismantling the batteries and separating the active materials, which primarily consist of lithium cobalt oxide (LiCoO2) and graphite. At operation 404, the Inductively Coupled Plasma (ICP) analysis is performed on the prepared black mass. ICP analysis is a technique used to determine the elemental composition of the black mass with high precision. The ICP analysis provides detailed information about the concentrations of various elements present in the black mass, such as lithium, cobalt, and other impurities. The data obtained from this analysis is crucial for optimizing the subsequent steps of the extraction process. At operation 406, the black mass is subjected to roasting. The roasting process involves heating the black mass at an elevated temperature in an inert atmosphere containing argon gas and carbon. The resulting product is a roasted black mass. At operation 408, the ICP analysis is conducted to evaluate the composition of the roasted black mass. During roasting, lithium cobalt oxide is converted into cobalt oxide and lithium is altered into a more leachable form. Thus, by analyzing the roasted black mass, the presence of lithium, cobalt, and other elements can be measured. At operation 410, the roasted black mass undergoes leaching. The roasted material is mixed with water at a predefined pulp density to extract lithium compounds into the solution. The leaching process results in a lithium-rich leach liquor and solid residues. The solid residues mainly consist of cobalt oxide, while the lithium ions remain dissolved in the leach liquor. At operation 412, the extracted lithium-rich leach liquor is filtered. The leach liquor is filtered to separate the solid residues from the lithium-rich solution. The solid residues are collected and can be processed further or disposed of, while the filtered lithium-rich solution is prepared for concentration.

[0053] Experiment:

[0054] In an experiment performed for selective lithium extraction from spent lithium-ion batteries.

[0055] Firstly, the black mass is made from spent lithium-ion batteries. Further, 100 gm of mixed black mass was prepared from the LFT battery. ICP analysis was performed on the prepared lOOgm of Black mass and found that it comprised Al- 1.39%, Co- 20.56%, Cu-0.79%, Fe-0.4%, Li-2.91%, Mn-6.31%, and Ni-5.32%. Further, 100 gm of LFP was also taken as a sample. Furthermore, the prepared black mass and LFP were subjected to roasting. Further, during the roasting process, the weight loss of the black mass and the LFP were recorded and is shown in the Table 1.

[0056] Table 1

[0057] In this regard of roasting process, both the black mass and the LFP were subjected a temperature of 750°C for 90 mins. Argon gas was flown at the rate of 1 Kg / hr. Argon gas and carbon were added in the ratio of 1: 1 in the prepared black mass. Further, during the ICP analysis, the elemental composition of the roasted black mass and the LFP were obtained through ICP analysis, which reveals the concentration of lithium and impurities present. Specifically, the data from the ICP analysis indicates the purity of the extracted lithium and the levels of contaminants as shown in Table 2, allowing for adjustments to the extraction process to enhance purity and efficiency.

[0058] Table 2

[0059] Thereafter, the roasted black masses were subjected to a water-leaching process.

[0060] The S / L ratio of the roasted black mass and water was maintained at 1:2. A motor of 500 RPM was used to mix water and the roasted black mass. The water leaching process was carried out at 22° C for 6 hours. Further, during the water leaching process, the data obtained from the water leaching process includes the concentration of lithium ions in the leachate and the efficiency of lithium extraction as shown in Table 3.

[0061] Table 3

[0062] Further, during the post-leaching analysis, the results of ICP analysis were conducted on the solid residue after leaching as shown in Table 4.

[0063] Table 4 Further, thermodynamic analysis of the decomposition of LiCoCh is shown here:

[0064] 1. Initial Decomposition (Equation 1): LiCoCL decomposes at temperatures above 900°C (1173 K).

[0065] The reaction is: 12LiCoO2 4CO3O4 + bLiiO + O2 (g)

[0066] The above reaction produces cobalt oxide (CO3O4), lithium oxide (Li2O), and oxygen gas.

[0067] 2. Further Decomposition (Equation 2): CO3O4 is unstable above 900°C (1173 K). It further decomposes as, 2CO3O46CoO + 02(g)

[0068] This produces cobalt (II) oxide (CoO) and more oxygen gas.

[0069] 3. Overall Reaction (Equation 3): Combining equations (1) and (2) gives the overall decomposition reaction:

[0070] 4LiCoO22Li2O + 4CoO + O2(g)

[0071] Examples:

[0072] Example 1:

[0073] In Example 1, the process for selective lithium extraction from waste lithium cobalt oxide (LCO) batteries is detailed. Waste LCO batteries are disassembled to extract the black mass, which includes both cathode and anode materials along with lithium compounds. The extracted black mass undergoes Inductively Coupled Plasma (ICP) analysis to determine its chemical composition, including the concentration of lithium. The black mass is roasted at 750 °C for 90 minutes in the presence of argon and carbon through carbothermal reduction process, which facilitates the breakdown of lithium compounds, making lithium more accessible for extraction. After roasting, the black mass is analyzed again using ICP to assess changes in its chemical composition and confirm the effectiveness of the lithium extraction process. The roasted black mass is leached with water at a pulp density of 10 percent for 6 hours at 23°C. The leach liquor, which contains dissolved lithium and carbonate ions, is filtered to separate it from the solid residue, which may contain other valuable metals. The filtered lithium solution undergoes ICP analysis to determine the percentage of lithium extracted. The analysis reveals that 98.5% of the lithium has been selectively leached into the solution. The lithium solution is concentrated by heating to achieve a lithium concentration of up to 20 grams per liter. The precipitated lithium carbonate is filtered to separate the solid lithium carbonate from the remaining solution. Both the remaining solution (raffinate) and the lithium carbonate salt are analyzed using ICP to determine the yield percentage and purity of the extracted lithium salts.

[0074] Example 2:

[0075] In Example 2, the procedure for extracting lithium from waste lithium iron phosphate (LFP) batteries is described. Waste LFP batteries are dismantled to extract the black mass, which includes cathode materials and lithium compounds. The black mass is analyzed using Inductively Coupled Plasma (ICP) to determine its chemical composition and lithium content accurately. The black mass is roasted at 750 °C for 90 minutes in an environment of argon and carbon. Following the roasting process, the black mass is analyzed again using ICP to assess changes in its chemical composition and verify the effectiveness of the lithium extraction process. The roasted black mass is subjected to water leaching at a pulp density of 10 percent for 6 hours at 23°C. The leach liquor, which contains dissolved lithium carbonate, is filtered to separate it from the solid residue. The solid residue may contain other valuable metals. The filtered lithium solution undergoes ICP analysis to determine the percentage of lithium extracted. The analysis indicates that 99.6% of lithium is present in the solution, with impurities remaining below 100 ppm. The lithium solution is concentrated by heating to achieve a lithium concentration of up to 20 grams per liter. The precipitated lithium carbonate is filtered to separate it from the remaining solution. Both the remaining solution (raffinate) and the lithium carbonate salt are analyzed using ICP to determine the yield percentage and purity of the extracted lithium salts.

[0076] Results:

[0077] Comparative data with the conventional methods shows that the method 100 achieves higher lithium recovery rates than conventional methods. For example, ICP testing results reveal that 93.98% of lithium salts were extracted with a purity of 99.3%. ICP Analysis of impurity levels in the extracted lithium solution demonstrates reduced impurity content compared to conventional methods. Quantitative data on energy consumption, emissions, and waste generation during the extraction process can reveal a reduced environmental impact compared to traditional methods.

[0078] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

Claims

CLAIMSWe claim:

1. A method (100) for selective lithium extraction from spent lithium- ion batteries, the method (100) comprising: preparing a black mass (302) from the spent lithium-ion batteries; roasting the black mass (302) at a predefined elevated temperature in an inert gas chamber comprising argon gas and carbon to obtain a roasted black mass; and leaching the roasted black mass with a defined amount of water forming a predefined pulp density to obtain a leach liquor.

2. The method (100) as claimed in claim 1, wherein the method (100) further comprises: filtering the leach liquor to separate a lithium-rich solution from solid residues; concentrating the lithium-rich solution through heating to achieve a lithium concentration of up to 20 grams per litre; precipitating lithium carbonate (308) from the concentrated solution by purging with carbon dioxide gas; and filtering the precipitated lithium carbonate (308) to obtain a high-purity lithium carbonate product.

3. The method (100) as claimed in claim 1, wherein roasting the black mass (302) is performed at a temperature ranging from 700°C to 800°C for a time duration ranging from 60 to 120 minutes.

4. The method (100) as claimed in claim 1 , wherein the predefined pulp density for leaching ranges from 5 % to 15 %.

5. The method (100) as claimed in claim 1, wherein leaching the roasted black mass is performed at a temperature ranging from 20°C to 30°C for a time duration ranging from 4 to 8 hours.

6. The method (100) as claimed in claim 1 , further comprises analyzing the black mass (302), the roasted black mass, and the lithium-rich solution using Inductively Coupled Plasma (ICP) analysis to determine chemical compositions of the black mass, the roasted black mass, and the lithium-rich solution.

7. The method (100) as claimed in claim 1, wherein the high-purity lithium carbonate product has a purity of at least 99%, and wherein the method (100) achieves a lithium recovery rate of at least 95%.

8. The method (100) as claimed in claim 1 , further comprises capturing and repurposing the carbon dioxide gas released during roasting for the precipitation of lithium carbonate (308), thereby creating a closed-loop system.

9. A system (202) for selective lithium extraction from spent lithium- ion batteries, the system comprises: a preparation unit (204) configured to prepare a black mass (302) from the spent lithium-ion batteries; a roasting unit (206) configured to roast the black mass at an elevated temperature in an inert atmosphere comprising argon gas and carbon to obtain a roasted black mass; a leaching unit (208) configured to leach the roasted black mass with water at a predefined pulp density to obtain a leach liquor; a first filtration unit (214) configured to filter the leach liquor to separate a lithium-rich solution from solid residues; a concentration unit (210) configured to concentrate the lithium-rich solution through heating to achieve a lithium concentration of up to 20 grams per litre; a precipitation unit (212) configured to precipitate lithium carbonate (308) from the concentrated solution by purging with carbon dioxide gas; anda second filtration unit (216) configured to filter the precipitated lithium carbonate to obtain a high-purity lithium carbonate product.

10. The system (100) as claimed in claim 1, further comprises: an analysis unit (220) configured to perform Inductively Coupled Plasma (ICP) analysis on the black mass, the roasted black mass, and the lithium- rich solution to determine their chemical compositions; and a Programmable Logic Controller (PLC) (218) operatively coupled to the roasting unit (206), the leaching unit (208), the concentration unit, (210), precipitation unit (212), the first filtration unit (214), second filtration unit (216), and the analysis unit (220), wherein the PLC (218) is configured to adjust operational parameters based on the ICP analysis results to optimize the selective lithium extraction.

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