Method for processing black collects to battery chemicals

Abstract

According to one example of the present invention, there is provided a method for processing a black mass into a battery chemical. The method includes leaching the black agglomerates with sulfuric acid and a reducing agent to produce a first process solution comprising lithium sulfate with at least one of manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate and impurities, the first process solution being separated from graphite by filtration. Thereafter, the method includes removing impurities from the first process solution using lithium hydroxide to produce a second process solution, separating lithium from the second process solution using chromatographic lithium separation to produce lithium sulfate and a third process solution, and separating at least one of copper, nickel and cobalt from the third process solution by ion exchange, thereby producing lithium sulfate. Finally, the process comprises converting the produced lithium sulfate into lithium hydroxide and sulfuric acid by electrodialysis for use in the process.

Description

Technical Field

[0001] The present invention relates to the recovery of nickel, cobalt, manganese and lithium from black agglomerates and their separation and purification. Background Art

[0002] As customer demand and technological readiness for appliances and electric vehicles increase, lithium-ion batteries (LIBs) are becoming increasingly important to fill the role of mobile energy storage. Although LIBs were invented in 1985, recent developments that improve energy density and production costs have significantly increased the demand for LIBs. The most common types of LIBs currently used for electric mobility are based on nickel, cobalt and manganese (NCM) or nickel, cobalt and aluminum (NCA) as cathode materials, and graphite as anode material. Although effective, the current price of raw materials makes these technologies quite expensive to deploy, while also causing significant amounts of greenhouse gas emissions during mining and processing into battery-grade chemicals.

[0003] In recent years, attempts to mitigate the prices and emissions caused by LIB production by recycling scrapped batteries have increased significantly. There are multiple routes for recycling, including pyrometallurgical and hydrometallurgical routes for metal recovery and separation. Currently, most of the recycled batteries are introduced into existing pyrometallurgical facilities, such as furnaces. Hydrometallurgical routes or combinations of routes are currently being built and tested around the world, and lithium leaching after reduction roasting is emerging as a potential route for lithium recovery. This technology is a first-step lithium recovery method that requires high temperatures (>500°C) and expensive reducing agents (e.g., hydrogen or coal), which significantly increases the carbon dioxide (CO2) footprint of the process.

[0004] The main production of lithium is concentrated in South America, where lithium-rich brines are pumped into huge evaporation ponds where they are concentrated by solar evaporation. The process takes up to two years. The lithium concentrate is then processed into lithium carbonate, which is finally converted into lithium hydroxide by a conversion reaction with lime and crystallized by evaporation. The advent of low-cobalt cathode materials favors hydroxide as a lithium source, which is easier to process from solid ores.

[0005] The methods used to recycle lithium batteries are generally divided into two main parts: mechanical processing and component recovery. In mechanical processing, the batteries are disassembled, shredded and separated into their main components: casing, electrode foil, electrolyte, plastic and electrode material. These components are then further processed to produce products.

[0006] In the hydrometallurgical route, a mixture of electrode materials, often referred to as black mass, is leached using a combination of an inorganic acid (e.g., sulfuric acid) and a reducing agent to dissolve soluble elements, and insoluble materials (such as graphite) can then be separated by filtration. The metals are then separated from one another and / or purified using pH adjustment or by liquid-liquid extraction techniques. The black mass is expected to contain 3-4% lithium by weight. Depending on the black mass or leaching step conditions, the process solution is expected to contain 2.5-4.5 g / l lithium, but higher lithium contents are possible.

[0007] The nickel, cobalt and manganese content varies depending on the CAM (cathode active material) chemistry. Other elements present may be aluminum and copper (from the electrode foil), fluorides and phosphorus (from the electrolyte salt, lithium hexafluorophosphate) and various miscible organic solvents and their degradation products (from the electrolyte solvent), as well as graphite and plastics (from the diaphragm material) from the anode active material (AAM). The above separation techniques, although widely used and robust, also cause certain problems. pH control and / or saponification in extraction are usually carried out by using sodium hydroxide or ammonium hydroxide or sodium carbonate. Therefore, after metal separation, sodium sulfate or ammonium sulfate remains in the process liquid and cannot be discharged to the environment, which increases the overall cost of the process if water purification is required. In liquid-liquid extraction, due to scaling, kerosene is replaced regularly, which significantly increases the carbon dioxide output of the process.

[0008] Document CN109402394A discloses a method for recovering valuable metals from lithium-ion battery electrode waste. The document teaches that leaching the electrode waste and then adjusting the pH with sodium hydroxide, potassium hydroxide or lithium hydroxide can produce a mixed precipitate of nickel hydroxide, cobalt hydroxide and manganese hydroxide and a lithium sulfate solution. The lithium sulfate solution is subjected to an electrodialysis step to produce a lithium hydroxide solution. The lithium hydroxide is crystallized by evaporation. The lithium hydroxide concentrate obtained after evaporation can be optionally circulated in the process, which will also recycle more impurities into the process. The mixed use of sodium hydroxide, potassium hydroxide and lithium hydroxide will cause serious difficulties in producing pure products and achieving battery-grade final products. In addition, the separation of elements will produce waste fractions.

[0009] Document CN108517409A discloses a method in which spent battery cathode material is subjected to a leaching step for nickel, cobalt, manganese and lithium, a purification step and a co-extraction step. After the co-extraction step, the resulting lithium sulfate can be subjected to an electrodialysis step and a crystallization step, from which the concentrated mother liquor can be recycled back to the purification step and the resulting sulfuric acid returned to the leaching step. Similar to CN109402394, this method produces a mixture of metals, and recycling the mother liquor will lead to the accumulation of impurities in the purification stage.

[0010] Therefore, in order to improve the sustainability of metal recovery from spent batteries and reduce the environmental impact of recycling spent batteries, it is necessary to reduce the amount of wastewater generated and the overall CO2 footprint of the process and to effectively recover lithium in the process. Summary of the invention

[0011] The object of the present invention is to provide a method for processing black lumps into nickel, cobalt, manganese and lithium products in a sustainable and environmentally friendly manner. Another object of the present invention is to purify and separate the metals while avoiding the use of caustic soda, ammonia or other chemicals that would require additional downstream processing. By producing process chemicals in situ from intermediates of the process, such as according to the method described in European Patent Application No. 20206690.8, process chemicals can be recycled in the process, thereby avoiding the need to discharge, for example, sodium sulfate or use ammonium and sodium products. For the avoidance of doubt, in situ production means the production of the required amount of process chemicals when required by utilizing the lithium salts produced in the process.

[0012] Furthermore, it is an object of the present invention to provide a method for recovering lithium and producing a lithium product.

[0013] According to one aspect of the present invention, there is provided a method for processing black agglomerates into battery chemicals, comprising the following steps:

[0014] 1) leaching the black mass with sulfuric acid and a reducing agent to produce a first process solution comprising: lithium sulfate, at least one of manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate, and impurities, and separating the first process solution from graphite by filtering;

[0015] 2) removing impurities from the first process solution using lithium hydroxide to produce a second process solution;

[0016] 3) separating lithium from the second process solution using chromatographic lithium separation to produce lithium sulfate and a third process solution;

[0017] 4) separating at least one of copper, nickel and cobalt from the third process solution by ion exchange, thereby producing lithium sulfate; and

[0018] 5) converting the lithium sulfate produced in step 3) and / or 4) into lithium hydroxide and sulfuric acid by electrodialysis, wherein the lithium hydroxide is used in at least one of steps 2), 3) and 4), and the sulfuric acid is used in step 1). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A method for processing black mass into battery chemicals according to a first embodiment is shown;

[0020] Figure 2A method for processing black mass into battery chemicals according to a second embodiment is shown;

[0021] Figure 3 A method for processing black mass into battery chemicals according to a third embodiment is shown;

[0022] Figure 4 A method for processing black mass into battery chemicals according to a fourth embodiment is shown; and

[0023] Figure 5 Chromatographic separation of lithium is shown. DETAILED DESCRIPTION

[0024] In the present context, the term "black mass" refers to a mixture of cathode and / or anode active materials separated from battery components. The black mass can come from spent Li-ion batteries or fresh / unused Li-ion batteries processed using any number of mechanical routes and / or from rejected cathode active material (CAM).

[0025] In the present context, the term "cathode active material (CAM)" refers, for example, to a lithium-containing cathode material (NCA) based on nickel, cobalt and aluminum or a cathode material (NCM) based on nickel, cobalt and manganese. Any other cathode active material containing lithium can also be used in the present method.

[0026] In the present context, the term "bed volume" refers to the volume of the resin bed packed into the column.

[0027] In the present specification, "removed" means that at least 90% by weight of the desired element or compound is removed, preferably at least 95% by weight, more preferably at least 98% by weight is removed.

[0028] The present embodiment is directed to the recovery and purification of elements such as nickel, cobalt, copper, manganese and lithium from the black mass and the recycling of lithium chemicals in the recovery and purification process.

[0029] A method for processing black mass into battery chemicals generally includes the following steps:

[0030] 1) leaching the black mass with sulfuric acid and a reducing agent to produce a first process solution comprising: lithium sulfate, at least one of manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate, and impurities, and separating the first process solution from graphite by filtering;

[0031] 2) removing impurities from the first process solution using lithium hydroxide to produce a second process solution;

[0032] 3) separating lithium from the second process solution using chromatographic lithium separation to produce lithium sulfate and a third process solution;

[0033] 4) separating at least one of copper, nickel and cobalt from the third process solution by ion exchange, thereby producing lithium sulfate; and

[0034] 5) Converting the lithium sulfate produced in step 3) and / or 4) into lithium hydroxide and sulfuric acid by electrodialysis, wherein the lithium hydroxide is used in at least one of steps 2), 3) and 4), and the sulfuric acid is used in step 1).

[0035] The method is able to use chemicals based on lithium (an element already present in the black mass), so the production of sodium sulfate can be avoided. In addition, the lithium chemical is prepared on-site and in situ from lithium sulfate, which is an intermediate produced during the hydrometallurgical processing of the black mass. Therefore, the produced lithium chemical is recycled to at least one of steps 1, 2, 3 and 4. On-site processing significantly reduces the overall carbon dioxide footprint of the process. In addition, ion exchange is used in an aqueous medium for the separation of the lithium element, which has multiple advantages over liquid-liquid extraction. In liquid-liquid extraction, kerosene needs to be replaced regularly due to scaling, which is eliminated in the present method. Therefore, lower operating costs (OPEX) can be achieved. In addition, the present method provides easier processing because there are no ATEX (equipment used in explosive environments) requirements.

[0036] Depending on the black mass, the first process solution includes: lithium sulfate, at least one of manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate. For example, the first process solution may include:

[0037] – lithium sulfate, manganese sulfate, nickel sulfate and cobalt sulfate,

[0038] – lithium sulfate, copper sulfate, nickel sulfate and cobalt sulfate, or

[0039] – Lithium sulfate, manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate.

[0040] According to one embodiment, in step 1), the solid concentration of the black mass in sulfuric acid may be 5-20 wt %, preferably 9-12 wt %.

[0041] In step 1), the mixture comprising the black mass and sulfuric acid may be heated to 60-90° C., preferably 70-80° C. The leaching of step 1) is performed in other ways as known in the art.

[0042] In step 1), the reducing agent may be, for example, hydrogen peroxide. After adding the reducing agent to the mixture, the mixture may be filtered for 0-4 hours, preferably 1-2 hours. This produces a first process solution containing metals and a filter cake of graphite / plastic solids. The first process solution is transferred to the next step in the process, and the filter cake may be packaged for reuse in graphite processing.

[0043] Step 2) of the method removes impurities from the first process solution to obtain a second process solution.

[0044] According to one embodiment, step 2) further comprises the step of precipitating manganese oxide before or after removing other impurities, and step 5) comprises converting the lithium sulfate produced in step 3) and / or 4) into lithium persulfate to be used in step 2) by electrolysis. According to a preferred embodiment, manganese oxide is precipitated before removing other impurities, i.e., manganese oxide is first precipitated from the first process solution, and then other impurities are removed from the manganese purification process solution obtained thereby. Therefore, preferably, manganese oxide is precipitated from the first process solution using lithium persulfate before removing other impurities using lithium hydroxide. The reason for this preferred order (manganese first, then other impurities) is that the oxidative precipitation method reduces the pH value of the process solution. If manganese is removed after removing other impurities, an additional pH adjustment step may be required before step 3). Therefore, removing manganese first enables the avoidance of an additional pH adjustment step before step 4). Therefore, in step 2), manganese (if present) is precipitated using an oxidative precipitation method. The oxidative precipitation method enables the use of lithium persulfate. Therefore, there is no need to use ammonium persulfate, and thus the generation of ammonium sulfate can be avoided.

[0045] If the removal of other impurities (i.e. impurities other than manganese, as used herein throughout) is performed before precipitation of manganese oxide, the method preferably comprises a step 3a) after step 2) and before step 3), which comprises adjusting the pH value of the second process solution with lithium hydroxide. After pH adjustment, the pH of the second process solution may be, for example, at least 3, preferably 3 to 6. Such a pH is preferred in view of the chromatographic separation of step 3).

[0046] According to one embodiment, in step 2), the concentration of lithium persulfate is 20-30 wt %, preferably 25-28 wt %.

[0047] In step 2), the first process solution in step 1) may be heated to 70-90° C., preferably 75-85° C. The lithium persulfate may be dosed according to the following:

[0048] MnSO4+Li2S2O8+H2O→MnO2+Li2SO4+H2SO4

[0049] According to one embodiment, the molar ratio of lithium persulfate (LiPS) to manganese sulfate is 0.95-1.3: 1, preferably 1-1.1: 1. LiPS is added to the reaction vessel, and since the reaction is endothermic, the temperature can be closely watched to ensure that the reaction is carried out under optimal conditions.

[0050] 1-5 hours, preferably 3-4 hours after the last addition of LiPS, the mixture can be filtered and the solid manganese oxide can be removed from the process solution. The manganese oxide can be packaged and stored for use in other processes. Alternatively, the manganese oxide can be further processed into manganese sulfate.

[0051] In addition, in step 2), potential organic solvents can also be oxidized by LiPS to CO2. This is a side effect of using oxidative LiPS.

[0052] According to one embodiment, the further impurities are selected from the group consisting of aluminium, fluoride and phosphorus. These impurities are removed from the process solution in step 2).

[0053] In step 2), the following equations can be considered to remove other impurities:

[0054] Al2(SO4)3+6LiOH→2Al(OH)3+3Li2SO4

[0055] Al(OH)3+3F - →AlF3

[0056] Al(OH)3+PO4 3- →AlPO4

[0057] Fluoride and phosphorus might be expected to be present as metal fluorides and phosphates, but may also be present as acids.

[0058] According to one embodiment, during the removal of other impurities, the pH value of the second process solution is 4-5.5, preferably 4.2-4.7.

[0059] Aluminum hydroxide can be reacted with the fluoride (F) and phosphorus (P) present for 1-6 hours, preferably 2-4 hours. This can precipitate phosphates to <1 ppm and fluoride to 20-60 ppm. The mixture can be filtered and the solid mixed Al / F / P filter cake can be packaged for disposal and / or reuse. The residual fluoride can be absorbed onto the alumina bed, which improves the purity of the downstream product. The second process solution obtained is then transferred to the next stage of the process.

[0060] According to some embodiments, the method further comprises a step 3b) before step 3) and after step 2) and the above optional step 3a), wherein step 3b) comprises removing residual fluoride from the second process solution. Residual fluoride can be removed by, for example, passing it through an activated alumina (AA) bed. AA can be used as an absorbent for fluoride, thereby reducing the fluoride content to <10ppm. For example, 50-200 bed volumes, preferably 100-150 bed volumes of process solution are pumped through the AA bed. The contact time of the process solution can be, for example, 3-8 minutes, preferably 5-6 minutes. The temperature can be, for example, 10-60°C, preferably 20-40°C.

[0061] According to one embodiment, the chromatography lithium separation in step 3) comprises:

[0062] - passing a second process solution containing lithium sulfate and at least one of nickel sulfate, cobalt sulfate and copper sulfate through a bed of acidic cation exchange resin,

[0063] - Collecting lithium residual solution containing lithium sulfate,

[0064] - eluting nickel sulfate, cobalt sulfate and copper sulfate from the acidic cation exchange resin bed with a strong acid solution to obtain an eluate, and

[0065] - Regenerating the acidic cation exchange resin bed with lithium hydroxide for repeated use.

[0066] The chromatographic lithium separation of step 3) can be performed, for example, as disclosed in European Patent Application No. 20206690.8, the description of which is incorporated herein by reference. This separation step produces lithium sulfate and a third process solution, which is directed to step 4) of the process.

[0067] In the first sub-step of the chromatography lithium separation, a second process solution containing lithium sulfate and at least one of nickel sulfate, cobalt sulfate and copper sulfate is passed through an acidic cation exchange resin bed. The resin bed can be, for example, a carboxylic acid or sulfonic acid resin bed. The pH value of the solution can be, for example, 3-6.5, preferably 4-5.5. For example, the throughput rate can be, for example, 0.5-6 bed volumes / hour (BV / h), preferably 2-4 BV / h.

[0068] In the second sub-step of the chromatography lithium separation, the lithium residual solution containing lithium sulfate can be collected at 0-1 bed volume (BV), preferably 0.5-1BV. Other elements, namely nickel sulfate, cobalt sulfate and copper sulfate, can be retained in the resin until the operating capacity is reached. The operating capacity can be predetermined by calculating the resin capacity according to the element content of the initial feed. On the other hand, the operating capacity can be detected online by visual inspection or spectral methods (such as UV) or other methods known to those skilled in the art. For a typical process solution containing 20-30g / l elements (i.e., the sum of lithium and other elements), the lithium residual solution can be collected at 0-3BV, preferably 0.5-2BV. The temperature during the chromatography separation can be 20-100°C, preferably 25-50°C, and the pressure in the column can be as high as 10bar from ambient pressure, preferably 1-5bar.

[0069] As an optional sub-step after the second sub-step, the lithium surplus solution can be recirculated through the resin bed multiple times to further improve the purity and concentration of lithium sulfate in the lithium surplus solution. The obtained lithium surplus solution can then be processed into lithium products such as lithium carbonate or lithium hydroxide using known hydrometallurgical methods.

[0070] In another sub-step that is also optional for the lithium residual solution, the lithium residual solution solution can be used to flush the resin bed to increase the purity and concentration of lithium in the lithium residual solution. The solution leaving the column after flushing can contain lithium salts and lithium hydroxide.

[0071] In the fourth substep of the chromatography lithium separation (carried out after the second substep or after the third optional substep, if used), other elements, namely nickel sulfate, cobalt sulfate and copper sulfate, can be eluted from the resin bed with 1-4BV of a strong acid solution. The strong acid solution can be, for example, a sulfuric acid or hydrochloric acid solution. The concentration of the strong acid solution can be, for example, 10-25% by weight, preferably 15-20% by weight. Alternatively, other applicable strong acids with similar concentrations can be used. The acid solution is fed at a rate of 1-6BV / h, preferably 2-4BV / h. Depending on the strong acid used, the resulting eluent may contain nickel, cobalt and / or copper in the form of salts such as sulfates or chlorides.

[0072] After elution, the resin bed may be washed with 0.5-2 BV, preferably 1-1.5 BV, of water to remove any residual eluent.

[0073] In the final sub-step, the resin can be regenerated using, for example, a 2-25 wt %, preferably 5-20 wt % lithium hydroxide solution. Lithium hydroxide can be fed through the resin bed at a rate of 1-6 BV / h, preferably 2-4 BV / h. After this step, the resin bed can be ready for reuse in separating lithium.

[0074] The number of columns in series may be 1 to 10, preferably 2 to 6. Other techniques may also be applied, such as simulated moving bed.

[0075] The eluate may then be processed into separate products using known metallurgical techniques, such as liquid-liquid extraction, or using the eluate processing methods described below.

[0076] In the eluent treatment method, an iminodiacetic acid (IDA) resin (e.g., LANXESS TP207 MDS) can be loaded with lithium by passing a 2-12 wt %, preferably 5-10 wt % lithium hydroxide solution through a resin bed, and then passing the eluent of the chromatography lithium separation as described above through the resin bed. The amount of eluent pumped through the resin bed can be, for example, 0.5-3 BV, preferably 1-1.5 BV, but this also depends on the initial feed concentration. The process separates nickel from cobalt by chromatography, thereby releasing lithium sulfate from the resin into the cobalt fraction. Nickel is recovered in the form of nickel sulfate for sale. Cobalt sulfate / lithium sulfate is generated for further processing. Then, the resin can be eluted with, for example, 1-3 BV (preferably 1.5-2 BV) of 5-25 wt % sulfuric acid (preferably 15-20 wt %) to obtain a nickel sulfate solution. The temperature at this stage can be 10-60° C., preferably 20-50° C.

[0077] Alternatively, any residual nickel in the cobalt fraction may be separated using a bispicolylamine resin bed or other methods known to those skilled in the art.The prior art also describes the option of using bispicolylamine instead of IDA resin to separate nickel and cobalt from the process solution.

[0078] As described above, in step 4), cobalt can be separated from the cobalt fraction by the same process as the initial lithium separation. In this process, nickel sulfate and cobalt sulfate for sale and lithium sulfate solution for further use are produced.

[0079] In step 4) of the method, at least one of copper, nickel and cobalt is separated from the third process solution by ion exchange. In the ion exchange, a chelated ion exchange resin can be used to separate nickel from cobalt. In this case, lithium is bound to the chelated ion exchange resin. When nickel is bound to the chelated ion exchange resin, lithium is released and mixed with cobalt. Therefore, step 4) can separate lithium sulfate from nickel and / or cobalt and / or copper, and produce lithium sulfate and a nickel sulfate / cobalt sulfate mixture for further processing, as well as a copper sulfate solution for sale.

[0080] Alternatively, copper sulfate may be eluted after step 1) or 2). In this case, copper sulfate does not need to be eluted in step 4).

[0081] In the final stage of the process, in step 5), the lithium sulfate collected from step 3) and / or 4) is converted into lithium hydroxide and sulfuric acid by electrodialysis, the lithium hydroxide being used in at least one of steps 2), 3) and 4), and the sulfuric acid being used in step 1). The concentration of the lithium hydroxide solution obtained from the process can be, for example, about 5-12% by weight, preferably 8-10% by weight. Therefore, the lithium chemicals required in the present method are prepared on-site and in situ from lithium sulfate. In addition, the production of sodium sulfate can be avoided by using lithium-based chemicals instead of commonly used sodium hydroxide.

[0082] In order to maintain a stable sulfate balance in the process, if the sulfate content increases during the process, lithium sulfate can be discharged as needed before electrolysis, and vice versa, if the sulfate content decreases, additional sulfate can be added in the form of sulfuric acid in step 1.

[0083] Lithium persulfate can be produced by electrolysis of lithium sulfate. In anodization, lithium sulfate can be passed through a cell. The cell can include a boron-doped diamond (BDD) anode, a platinum or iron (steel) cathode, and a cation exchange membrane. The cation exchange membrane can be, for example, Nafion N424. The current density can be, for example, 250-2500 A / m 2 , preferably 500-1250A / m 2 . Lithium persulfate is formed at the anode. The cathode electrolyte in the battery can be an aqueous conductive solution, such as a sulfate solution. The reaction can be continued until the desired lithium persulfate concentration is reached. Therefore, the lithium persulfate used in step 2) can come from step 5 of the method, i.e. can be recycled.

[0084] Optionally, additional sulfate may be added to the lithium sulfate prior to the electrolysis in step 5). Such sulfate may be, for example, sulfuric acid or sodium sulfate. The amount of excess sulfate may be, for example, 0.5-10% by weight, preferably 1-5% by weight, of the lithium sulfate content.

[0085] Once the desired concentration is reached, lithium persulfate can be pumped from the system into a storage tank and fresh lithium sulfate can be added to the system. As lithium persulfate is withdrawn from the process, equivalent lithium sulfate can be pumped into the system.

[0086] According to one embodiment, sulfuric acid produced by electrodialysis is used in step 3) or 4). Therefore, sulfuric acid can be directed to step 3) or 4) in addition to step 1). If sufficient sulfuric acid is produced, it can be used in all steps 1), 3) and 4).

[0087] According to one embodiment, step 5) further comprises concentrating the lithium hydroxide before using it in at least one of steps 2), 3) and 4). Thus, the lithium hydroxide can be ready for use in steps 2), 3) and 4).

[0088] According to another embodiment, step 5) further comprises concentrating sulfuric acid before use in at least one of steps 1), 3) and / or 4). Thus, in this case, sulfuric acid can be ready for use in step 1) and optionally in step 3) or 4).

[0089] According to one embodiment, step 5) further comprises crystallizing the excess lithium hydroxide. Thus, the excess lithium hydroxide not required in the process can be processed for further use, such as storage or sale. Preferably, the excess lithium hydroxide can be crystallized into lithium hydroxide monohydrate. Crystallization can be performed by evaporation.

[0090] Detailed description of the drawings

[0091] Figure 1 A method for processing black mass into battery chemicals according to a first embodiment is shown. In a first step, the black mass 1 is fed to a leaching 2 where it is leached using, for example, sulfuric acid (H2SO 4) and hydrogen peroxide (H2O2) to produce a first process solution and graphite. After separation from graphite 4, the first process solution 3 is directed to a second process step. In a second step 5, impurities such as aluminum (Al), fluoride (F) and phosphorus (P) are removed from the first process solution 3 using lithium hydroxide (LiOH). Impurities 6 are separated and the solution, i.e., a second process solution 7, is directed to a third step. In a third step 8, the second process solution 7 from which impurities have been removed is treated using a chromatographic lithium separation method, thereby separating lithium from the second process solution, producing lithium sulfate 9 and a third process solution 10, which is directed to a fourth step. In the fourth step, copper (Cu), nickel (Ni) and / or cobalt (Co) are separated from the third process solution by ion exchange 11 using lithium hydroxide, and lithium sulfate (Li2SO4) is also formed. Finally, the lithium sulfate collected from the third and fourth steps is converted into lithium hydroxide and sulfuric acid by electrodialysis 12. The lithium hydroxide is transferred to the second step and to the third and fourth steps. The sulfuric acid is transferred to the first step and optionally to the third and fourth steps. Optionally, the method further comprises crystallizing 22 the excess lithium hydroxide after the electrodialysis 12. Optionally, advantageously, the method further comprises crystallizing 22 the excess lithium hydroxide after the electrodialysis 12 as lithium hydroxide monohydrate.

[0092] Figure 2A second embodiment of the method is shown. In this embodiment, prior to the second step described above, manganese oxide (MnO2) is precipitated from the first process solution 3 using lithium persulfate (Li2S2O8) in a precipitation step 14. The manganese oxide 15 is further processed into manganese sulfate (MnSO4) via dissolution and purification 16. The rest of the process is as follows Figure 1 In the embodiment shown in FIG. 1 , the first process solution 17 free of manganese is directed to an impurity removal step. In addition, the process comprises an electrolysis 13 which converts lithium sulfate into lithium persulfate for use in a manganese precipitation 14 .

[0093] Figure 3 A third embodiment of the method is shown. In this embodiment, in combination with Figure 1 After the above-mentioned second step, manganese oxide (MnO2) is precipitated from the second process solution 7 in a precipitation step 14. Thereafter, the pH value is adjusted in a separate step 18 and the thus obtained manganese-free second process solution 19 is introduced to a chromatographic separation.

[0094] Figure 4 A fourth embodiment is shown in which an optional further step is shown, namely a step of partially removing lithium sulfate from the process in case of excess accumulation in step 21. Likewise, an optional step is to replenish sulfuric acid 20 if necessary. This need may increase, for example, when the composition of the black mass changes.

[0095] Example

[0096] The black mass containing the NCM-based cathode material was dissolved in sulfuric acid using hydrogen peroxide as a reducing agent to obtain a dissolved black mass process solution. The mixture was filtered and the filtrate was analyzed for metal content using an inductively coupled plasma emission spectrometer (ICP-OES) (Thermo Scientific), fluoride content using an ion selective electrode (ISE), and total organic content (TOC) using a Shimadzu TOC-L instrument. Table 1 is an analysis of a typical process solution after leaching, and the following examples are obtained from solutions such as these. Unless otherwise stated, the analytical methods for elements in all experiments were also the same.

[0097] Table 1. Elemental contents of typical process solutions from leached black pellets

[0098]

[0099]

[0100] Aluminum, copper, fluoride, phosphorus and TOC contents may vary depending on the technology selected for producing black agglomerates from LIBs.

[0101] Example 1

[0102] A 200 g / l lithium sulfate solution was circulated through a BDD anode and a platinum cathode (both 100 cm 2 ) Electro-MP cell (Electrocell). A current of 12.5 A is induced from the power supply. During this process, the temperature is kept at a stable 20°C. The cycle is allowed to continue for about 6.5 hours, samples are taken regularly, and the persulfate concentration is determined by colorimetric back titration. After 6 hours, the persulfate concentration has reached 240 g / l and stabilized. The current is stopped and the persulfate solution is stored.

[0103] In a jacketed glass reactor, 2000 ml of the process solution was heated to 80°C under constant stirring at 300 rpm. 400 ml of 240 g / l lithium persulfate solution was added. The temperature of the mixture dropped and it was heated to 80°C. 4 hours after the addition of LiPS, the mixture was filtered and the filtrate was analyzed. The results of the analysis are presented in Table 2.

[0104] Table 2. Composition of the filtrate from the manganese oxide precipitation

[0105] element mg / l Al,ICP-OES 1640 Co,ICP-OES 7237 Cu,ICP-OES 2573 Li,ICP-OES 5605 Mn,ICP-OES 2 Ni,ICP-OES 8160 P,ICP-OES 34 F,ISE 121 TOC 45

[0106] Thus, manganese is selectively precipitated to low levels with no loss of nickel / cobalt. In this step, some phosphorus is also removed and most of the organic solvent has been oxidized to carbon dioxide.

[0107] Example 2

[0108] 2200 ml of the process solution from Example 1 were heated to 80° C. The pH was increased to 5 with 128 g / l of LiOH solution, a total of 833 ml was required. The solution was added by pumping at a rate of 1 ml / min. One hour after the pH was reached, the mixture was filtered and the filtrate was analyzed, the results of which are presented in Table 3.

[0109] Table 3. Composition of the filtrate from aluminum, fluoride and phosphorus precipitation

[0110] element mg / l Al,ICP-OES 20,1 Co,ICP-OES 5192 Cu,ICP-OES 933,6 Li,ICP-OES 11660 Mn,ICP-OES <0,10 Ni,ICP-OES 5826 P,ICP-OES 0,4 F,ISE 41 TOC 27

[0111] Thus, aluminum is selectively precipitated, which also precipitates a large amount of fluoride and all of the phosphorus. The reduction in metal concentration is primarily due to dilution, which can be reduced by using a slurry with a strong lithium hydroxide solution.

[0112] Example 3

[0113] 5 1 of the process solution from Example 2 above were pumped into 60 g of activated alumina with a retention time of 5 minutes. All fractions were collected and analyzed and the results are presented in Table 4.

[0114] Table 4. Composition of process solution after treatment with activated alumina

[0115] element mg / l Al,ICP-OES 0,4 Co,ICP-OES 6275 Cu,ICP-OES 911 Li,ICP-OES 9225 Mn,ICP-OES <0,10 Ni,ICP-OES 7083 P,ICP-OES <1,4 F,ISE <10 TOC <20

[0116] Fluoride, phosphorus and aluminum are absorbed by the activated alumina, and all other metals remain in solution.

[0117] Example 4

[0118] Three (3) YMC ECO25 chromatography columns were packed with 310 ml of Finex CA16G-HP resin with carboxylic acid functional groups per column. The resin was loaded with lithium by passing 1 BV of a 10 wt % lithium hydroxide solution through the columns at 0.5 BV / h. 1500 ml of the process solution from Example 3 was then pumped through the column series starting with column 1 at 1 BV / h, followed by 310 ml of water, 260 ml of 20 wt % sulfuric acid and finally another 310 ml of water and 310 ml of 10 wt % LiOH solution through column 1. These cycle parameters were continued by feeding column 2, then column 3, and then repeated for column 1. A 120 ml sample was collected and analyzed. The cycle was repeated six times, for a total of two times in all columns, and the results are presented in Figure 5 middle.

[0119] Figure 5 It is shown that lithium is clearly separated from nickel, cobalt and copper. In the figure, the solid lines represent the curves for nickel, cobalt and copper, while the dashed line represents lithium. V (BV) represents the volume of the resin bed used, while c represents the concentration (in mg / l).

[0120] Example 5

[0121] Three (3) YMC ECO25 chromatographic columns were loaded with 300 ml of Lewatit MonoPlus TP207 H+ resin with iminodiacetic acid functional groups per column. 540 ml of 10 wt % LiOH solution was pumped through the resin column, followed by 2000 ml of water, followed by 1000 ml of process solution from lithium separation (from Example 4), followed by 1600 ml of water. 710 ml of lithium fraction was collected, followed by 700 ml of cobalt fraction. The column was eluted with 300 ml of 20 wt % sulfuric acid and finally washed with water until the flow-through was clear. 500 ml of nickel fraction was collected. 100 ml samples were collected and analyzed, and a mass balance of nickel, cobalt and lithium was prepared, presented in Table 5.

[0122] Table 5. Mass balance of nickel, cobalt and lithium during separation of nickel and cobalt

[0123] weight% nickel cobalt lithium Co 22 wt% 87% by weight 0% by weight Li 0% by weight 23 wt% 80% by weight Ni 67% by weight 39 wt% 0% by weight

[0124] Thus, the separation of nickel and cobalt is clear, with minimal loss of lithium in the cobalt fraction. The cobalt fraction can then be purified to recover lithium by a process similar to that described in Example 4.

[0125] It should be understood that the embodiments of the present invention disclosed are not limited to the specific structures, process steps or materials disclosed herein, but are extended to equivalent schemes that will be recognized by those skilled in the relevant art. It should also be understood that the terms used herein are only used to describe specific embodiments and are not intended to be limiting.

[0126] The "embodiment" mentioned throughout this specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment.

[0127] The verb "to comprise" is used in this document as an open limitation, which neither excludes nor requires the presence of unrecited features. The features recited in the dependent claims may be freely combined with each other unless expressly stated otherwise. Furthermore, it should be understood that the use of "a" or "an", i.e. the singular, throughout this document does not exclude the plural.

Claims

1. A method for processing black mass into battery chemicals, comprising the following steps: 1) leaching the black mass with sulfuric acid and a reducing agent to produce a first process solution comprising: lithium sulfate, at least one of manganese sulfate, copper sulfate, nickel sulfate and cobalt sulfate, and impurities; separating the first process solution from graphite by filtering; 2) removing impurities from the first process solution using lithium hydroxide to produce a second process solution; 3) separating lithium from the second process solution using chromatographic lithium separation to produce lithium sulfate and a third process solution; 4) separating at least one of copper, nickel and cobalt from the third process solution by ion exchange, thereby producing lithium sulfate; and 5) converting the lithium sulfate produced in step 3) and / or 4) into lithium hydroxide and sulfuric acid by electrodialysis, wherein the lithium hydroxide is used in at least one of steps 2), 3) and 4), and the sulfuric acid is used in step 1).

2. The method according to claim 1, wherein step 2) further comprises the step of precipitating manganese oxide before or after removing other impurities, and step 5) comprises converting the lithium sulfate produced in step 3) and / or 4) into lithium persulfate by electrolysis for use in step 2).

3. The method according to claim 1 or 2, wherein in the step 1), the solid concentration of the black mass in sulfuric acid is 5-20 wt%, preferably 9-12 wt%.

4. The method according to any one of the preceding claims, wherein in step 2), the concentration of lithium persulfate is 20-30 wt%, preferably 25-28 wt%.

5. The method according to any one of the preceding claims, wherein additional sulfate is added to the lithium sulfate prior to the electrolysis in step 5).

6. The method according to any one of the preceding claims, wherein in step 2), the molar ratio of lithium persulfate to manganese sulfate is 0.95-1.3:1, preferably 1-1.1:

1.

7. The method according to any one of the preceding claims, wherein the impurities are selected from the group consisting of aluminum, fluorides and phosphorus.

8. A method according to any one of the preceding claims, wherein the pH of the second process solution is 4-5.5, preferably 4.2-4.

7.

9. The method according to claim 7, wherein the method further comprises a step 3a) before the step 3), the step 3a) comprising removing residual fluoride from the second process solution.

10. The method according to any one of the preceding claims, wherein the chromatographic lithium separation of step 3) comprises: - passing a second process solution containing lithium sulfate and at least one of nickel sulfate, cobalt sulfate and copper sulfate through a bed of acidic cation exchange resin, - Collecting lithium residual solution containing lithium sulfate, - eluting nickel sulfate, cobalt sulfate and copper sulfate from the acidic cation exchange resin bed with a strong acid solution to obtain an eluate, and - Regenerating the acidic cation exchange resin bed with lithium hydroxide for repeated use.

11. The method of claim 10, wherein the lithium surplus solution is recycled through the acidic cation exchange resin bed.

12. The process according to any one of the preceding claims, wherein sulfuric acid produced by electrodialysis is used in step 3) or 4).

13. The method according to any one of the preceding claims, wherein step 5) further comprises concentrating the lithium hydroxide before using it in at least one of steps 2), 3) and 4).

14. The process according to any one of the preceding claims, wherein step 5) further comprises concentrating the sulfuric acid before using it in at least one of steps 1), 3) and / or 4).

15. The method according to any one of the preceding claims, wherein step 5) further comprises crystallizing excess lithium hydroxide for further use.

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