Method for recovering cathode materials in battery recycling

Abstract

1. A method for removing aluminum and iron in recycling rechargeable batteries, comprising: preparing a leachate from black mass; adding phosphoric acid (H3PO4) to the leachate and adjusting the pH to form iron phosphate (FePO4) and aluminum phosphate (AlPO4); precipitating and removing the formed FePO4 and AlPO4; and forming a filtrate for further recovery of cathode metals, primarily NMC metals and lithium.

Description

[Technical field]

[0001] The present invention relates to process steps in the recycling of batteries and in particular the recovery of cathode materials such as lithium (Li), nickel (Ni), manganese (Mn) and cobalt (Co), which are often referred to as NMC metals. [Background technology]

[0002] The transition from fossil fuels to renewable energy is gaining considerable momentum. One of the most important factors is the development of better and cheaper rechargeable batteries. Currently, lithium-ion batteries are becoming more and more popular. It is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back during charging. As a result of this popularity, the demand for elements required for lithium-ion batteries is growing exponentially. These elements include, besides lithium, NMC metals, especially cobalt. The global sources of cobalt appear to be depleting, so the focus is now shifting from cobalt extraction to recovery. In addition, cobalt mining is associated with serious environmental and social negative impacts in some countries, e.g. pollution, child labor, etc.

[0003] Economical and environmentally friendly recycling of lithium batteries is necessary to conserve natural resources and minimize pollution. In addition, recycling would provide a sustainable source for the production of new batteries. Currently, lithium-ion battery recycling is still in the early stages of development. One of the major obstacles at this stage is the lack of a stable supply. With an increasing amount of expired batteries, it will be easier to develop cost-effective technologies and globally standardized methods. Also, the high recycling costs create a barrier to profitability and hinder the development of a large-scale market. Another issue to consider is that lithium-ion batteries from different manufacturers use different chemical processes to store and release energy, which makes it difficult to create a standardized recycling procedure.

[0004] In conclusion, the expected increase in demand for raw materials for lithium-ion batteries, the criticality of cobalt reserves, and the uncertainty of lithium supply and price make the development of efficient and cost-effective recycling methods highly desirable.

[0005] US Patent Application Publication No. 2011 / 0059339 (H. Yamasaki et al.) discloses a method for treating lithium batteries. The method includes an acid solution treatment process in which an acid solution, i.e., an aqueous phosphoric acid solution, aqueous carbonated water, or hydrogen sulfide water, is contacted with the surfaces of the positive electrode active material layer and the positive electrode current collector that constitute the positive electrode member. The positive electrode active material layer is then separated from the positive electrode current collector, and the treated material containing metal components derived from the positive electrode active material layer is subjected to an oxalic acid treatment process in which the treated material is reacted with an aqueous oxalic acid solution.

[0006] DE 102014014894 (Adensis GmbH) discloses a method for recovering material from the cathode of a lithium-ion battery. The method comprises acid stripping of the cathode material from the substrate material using an oxidizing or non-oxidizing acid. As oxidizing acid, preferably nitric acid, phosphoric acid and / or sulfuric acid can be used.

[0007] EP 2532759 (SARP Industries) discloses a method for separating materials from lithium batteries, which method comprises leaching the ground material in an acidic medium to dissolve a portion of the ground material, obtaining a solution containing metal ions and a portion of the insoluble ground material, and separating the metal ions present in the solution. The acid used in the leaching step is selected from mineral acids, such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and mixtures of one or more thereof. The preferred acid is sulfuric acid.

[0008] EP 2450991 (Eco Recycling SRL) discloses a method for the treatment of end-of-life accumulators and batteries of any kind, except alkaline, zinc-carbon and lead-acid batteries. The method comprises a first stage of physical operations and a second stage of chemical operations, which, combined, allow the recovery of nickel-metal hydride accumulators, lithium-ion accumulators and batteries, copper and plastic materials normally present in primary lithium batteries. The method produces a high purity lithium product (Li 2 CO 3 ), cobalt (Co / CoSO 4 / CoCO 3 ) and nickel (Ni / NiCO 3 It is characterized by the use of a purification operation using a solvent that makes it possible to obtain

[0009] WO 2018 / 0209164 (Worcester Polytechnic Institute) relates to the extraction of Co, Ni, Al and Mn for the production of new battery cathode active materials. LiFePO 4 is generated as a waste stream and is often discarded due to the impossibility of recycling. WO 2018 / 0209164 describes FePO which forms a by-product along with graphite and carbon that are not dissolved in solution. 4 LiFePO as 4 The precipitation of FePO 4 LiFePO as a cathode material, separated from graphite and carbon 4 while the graphite can be recycled as an anode material. Summary of the Invention

[0010] Given the increasing demand for metals used in rechargeable lithium-ion batteries and growing environmental concerns, improved methods for recovering cathode metals remain to be developed.

[0011] A first aspect of the present invention provides a method for removing aluminium and iron in the recycling of rechargeable batteries, preferably rechargeable lithium-ion batteries, comprising the steps of: a) preparing an exudate from the black mass; b) The leachate from step a) is treated with phosphoric acid (H 3 PO 4 ) adding c) Adjust the pH to iron phosphate (FePO 4 ) and aluminum phosphate (AlPO 4 ), d) The formed FePO 4 and AlPO 4 and e) forming a filtrate for recovering the cathode metal. The method includes:

[0012] According to one embodiment of said aspect, the precipitation is carried out in two separate steps with different pH.

[0013] In the first precipitation step, the pH is adjusted to 1.5 to 4, for example 1.5 to 3.5, preferably 1.5 to 3, optionally using an alkali.

[0014] In the second step, the pH is adjusted to 2.5 to 6.5, for example, 2.5 to 6, and preferably 2.5 to 4.

[0015] According to one embodiment, which can be freely combined with the above, in the first precipitation step, seed crystals are added to form FePO 4 and AlPO 4 Allow to precipitate.

[0016] Preferably, the seed crystals comprise aluminum and iron phosphate crystals, and the seed crystals are added in an amount of 0.05-0.3 g / L, for example 0.05-0.2 g / L, preferably 0.05-0.15 g / L.

[0017] The first and second precipitation steps are preferably carried out at a temperature of 20 to 95°C, for example 55 to 95°C, for example 55 to 85°C, preferably 65 to 75°C.

[0018] Preferably, the residence time of each precipitation step is from 2 to 24 hours, for example from 12 to 18 hours, for example from 2 to 12 hours, preferably from 2 to 6 hours.

[0019] According to one embodiment, which can be freely combined with the above aspects and embodiments, in the first precipitation step a larger amount of FePO is present than in the second precipitation step. 4 and AlPO 4 The first precipitate is removed by filtration and the leachate containing traces of aluminum and iron is conducted to a second precipitation step where the pH is adjusted to 2.5-6.5, for example 2.5-6, preferably 2.5-4. A second precipitate is formed and removed by filtration. The resulting leachate is substantially free of aluminum and iron and rich in NMC metals and lithium. If the leachate from the black mass was substantially free of copper, the resulting leachate is also free of copper. If the leachate from the black mass contained copper, this can be removed after removal of aluminum and iron, for example by precipitation or solvent extraction.

[0020] Optionally, this leachate is subjected to further processing to separate the lithium and precipitate the NMC metals in the form of hydroxides.

[0021] According to one embodiment, which can be freely combined with the above aspects and embodiments, FePO 4 and AlPO 4 The precipitate containing is washed with an acidic aqueous solution, preferably with an aqueous solution having a pH of 1.5-5.5, preferably 1.5-2.5. The precipitate formed in the first precipitation step as well as in the second precipitation step is washed with said acidic aqueous solution and the acidic filtrate is recycled to the black mass leaching unit.

[0022] The leachate from the black mass preferably contains substantially zero copper or only a small amount of copper, preferably less than 10 ppm, preferably less than 5 ppm copper. In another example, the leachate may contain copper, in which case the copper is removed following the removal of aluminum and iron.

[0023] Various aspects will now be described by way of example with reference to the drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 shows a schematic flow chart of a method for recovering cathode metals in battery recycling. In this flow chart, the leaching step (A) is followed by a filtration step (B) from which the leaching residue is led to a washing step (W). The filtrate from B is led to an associated copper recovery step (D), for example a copper extraction step (C) involving solvent extraction of copper with (a mixture of) one or more copper-specific extracting compounds followed by copper electrowinning or electrowinning, to obtain copper metal. The leachate substantially free of copper is then led to an aluminum and iron precipitation unit (E). After removal of copper, aluminum and iron, in step (F) the NMC metals are recovered together with a minimal amount of lithium. In step (G), this minimal amount of lithium is selectively dissolved to obtain a cake of NMC hydroxide. The lithium-rich solution from step F is led to a lithium recovery unit (H). The washing solutions from steps W and G can be recycled to the initial leaching step A. [Diagram 2] Figure 2 is a flow chart showing an outline of an embodiment of the Al and Fe phosphate precipitation operation in one step. A leachate (X) containing substantially no or only small amounts of copper enters a first precipitation tank 200 via a pH adjustment unit 100. After a predefined residence time, the contents of the tank 200 are filtered in a filter 300 to obtain a precipitate and a leachate (Y), which is substantially free of copper, aluminum and iron, and rich in NMC metals and lithium. The precipitate is directed to a washing unit 310 where it is exposed to an acidic washing solution to obtain a washed precipitate (Z) of FePO4 and AlPO4 containing traces of coprecipitated Li. [Diagram 3] Figure 3 is a flow chart showing an overview of an embodiment of the Al and Fe phosphate precipitation operation in two steps. A leachate (I) containing substantially zero or only small amounts of copper enters a first precipitation tank 200 via a pH adjustment unit 100. After a predefined residence time, the contents of the tank 200 are filtered in a filter 300 to obtain a precipitate and a leachate. The precipitate is led to a washing unit 310 to be exposed to an acidic washing solution, while the leachate is led to a second precipitation tank 500 via a pH adjustment unit 400. After a residence time, which can be the same or different from the previous step, the contents of the tank 500 are filtered in a filter 600 to obtain a leachate IV substantially free of copper, aluminum and iron and rich in NMC metals and lithium, and a precipitate containing aluminum and iron remaining in the form of phosphates, which is washed in a unit 610. [Figure 4] Figure 4 is a graph based on Example 2 showing how the precipitation yield of certain elements as phosphate salts changes with different pH values. Starting at about pH 1 and increasing, different elements precipitate at different pHs. Fe and Al precipitation begins at pH 2, and at pH 3.2, precipitation is greater than 99 and 95%, respectively. P shows a similar trend as Al. For Cu and Zn, precipitation begins at a pH greater than 3, reaching a precipitation yield of nearly 100% at about pH 6.4. For Co, Ni, Mn and Mg, the precipitation yield does not exceed 60% even when the pH is increased to about 6.4. Li does not precipitate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Before describing the present invention, it is to be understood that the scope of the present invention will be limited only by the claims and their equivalents, and therefore the terminology used herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0026] Batteries can be broadly classified as disposable and rechargeable. Disposable batteries are primarily of the alkaline type, meaning that the cathode is manganese oxide, the anode is zinc powder, and the electrolyte is potassium hydroxide. Currently, many disposable batteries end up in landfills. Rechargeable batteries are based on a variety of chemistries, exemplified by the increasingly popular lithium-ion battery, which uses lithium cobalt oxide as the cathode and carbon as the anode. Other examples are nickel-cadmium, nickel-zinc, and nickel-metal hydride batteries. Rechargeable batteries can be recharged hundreds, or even thousands, of times and can be used for long periods of time, but eventually must be disposed of. To minimize waste and conserve the earth's resources, it is necessary to recycle both disposable and rechargeable batteries and recover their components. In this specification, the term "battery" is intended to include both disposable and rechargeable batteries. Batteries include many different materials, such as the plastics and metals that make up their housing, the cathode and anode materials, and the electrolyte. Battery recycling begins with separating waste batteries according to their chemical composition and then crushing or shredding them. The shredded batteries are transported on a conveyor belt to a vibrator where they pass through a series of filters. Plastic and metal fragments are separated, washed and collected for recycling.

[0027] This shredding and refining process results in a product called "black mass" that contains electrolyte, cathode and anode materials, and other components. Because batteries are difficult to separate and may be neglected, the composition of black mass varies. Examples of different compositions of black mass (BM) rich in either nickel, NMC, or cobalt are shown in Table 1 below.

[0028] [Table 1]

[0029] Thus, in this specification and claims, the term "black mass" is used to describe the contents of crushed or shredded batteries that are fed into a recycling process after removal of plastics, solid metal parts, etc.

[0030] The terms "cathode material" and "cathode metal" are used interchangeably to describe the material or metal that makes up the cathode of a battery. Common cathode materials are lithium cobalt oxide (also called lithium cobalt oxide), lithium manganese oxide (also known as spinel or lithium manganate), lithium iron phosphate, as well as lithium nickel manganese cobalt (often abbreviated as NMC) and lithium nickel cobalt aluminum oxide (NCA).

[0031] Most lithium-ion batteries use graphite powder as the anode material, however the term "anode material" includes natural and synthetic graphite, activated carbon, carbon black, conductive additives, LTO (lithium titanate), surface functionalized silicon and high performance powdered graphene.

[0032] Finally, it should be noted that, in this specification and the claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0033] A first aspect of the present invention is a method for recovering aluminum and iron in the recycling of rechargeable batteries, comprising the steps of: a) preparing an exudate from the black mass; b) The leachate from step a) is treated with phosphoric acid (H 3 PO 4 ) adding c) Adjust the pH to iron phosphate (FePO 4 ) and aluminum phosphate (AlPO 4 ), d) The formed FePO 4 and AlPO 4 and e) forming a filtrate for recovering the cathode metal. The present invention relates to a method comprising the steps of:

[0034] The leachate in step a) is preferably substantially free of copper, meaning that it contains substantially zero copper or only small amounts of copper, preferably less than 10 ppm, preferably less than 5 ppm. In another example, the leachate may contain copper, which can be removed following removal of aluminium and iron, for example by precipitation or solvent extraction.

[0035] The pH of the leachate will usually be less than 1.5, such as less than 1, preferably less than 0.7, such as about 0.5.

[0036] Iron and aluminum have low solubility as trivalent phosphates, and therefore do not contain H 3 PO 4 Addition of 0.1% to 10% Fe effectively precipitates iron and aluminum for further recovery. Precipitation of Fe and Al in the form of phosphates is advantageous compared to precipitation in the form of hydroxides, since the hydroxides of Al and Fe tend to absorb NMC metals and lithium. Furthermore, the phosphates of Al and Fe are easier to separate by filtration and easier to wash than the corresponding hydroxides.

[0037] According to one embodiment of said aspect, the precipitation is carried out as two separate steps with different pH, which is advantageous as it can increase the efficiency of aluminum and iron removal. In such a case, the first step may be carried out under the same conditions as the single step precipitation.

[0038] In the first precipitation step, the pH is adjusted, optionally using an alkali, to 1.5 to 4, for example 1.5 to 3.5, preferably 1.5 to 3. In the second step, the pH is adjusted, optionally using an alkali, to 3 to 6.5, for example 3 to 6, preferably 3 to 5.5.

[0039] Preferably, in the first precipitation step, seed crystals are added to precipitate FePO 4and AlPO 4 The addition of seeds promotes the crystallization and precipitates FePO 4 and AlPO 4 This facilitates aggregation of the ions, allowing for efficient separation by filtration.

[0040] Preferably, the seed crystals comprise aluminum and iron phosphate crystals, and the seed crystals are added in an amount of 0.05-0.3 g / L, for example 0.05-0.2 g / L, preferably 0.05-0.15 g / L.

[0041] The first precipitation at a low pH has the advantage that it minimizes co-precipitation of lithium and the NMC metals. When the second precipitation step is performed, less solids are present. This is advantageous because it negates the tendency for co-precipitation at higher pH.

[0042] The first and second precipitation steps are usually carried out at 20-95° C., for example 55-95° C., for example 55-85° C., preferably 65-75° C. The advantage of this is that the higher the temperature the more efficient the precipitation.

[0043] The residence time of the precipitation step is usually 2 to 24 hours, for example 12 to 18 hours, for example 2 to 12 hours, preferably 2 to 6 hours, which advantageously allows the production of a large amount of FePO 4 and AlPO 4 The formation and aggregation of is possible. Temperature and time are correlated: the higher the temperature, the shorter the time and vice versa.

[0044] Preferably, FePO can be precipitated. 4 and AlPO 4 Since more FePO is present in the first leachate, the first precipitation step produces a larger amount of FePO than the second precipitation step. 4 and AlPO 4 Allow to precipitate.

[0045] Preferably, for efficient cleaning, FePO 4 and AlPO 4The precipitate containing is washed with an aqueous solution having a pH of 1.5 to 5.5, preferably 1.5 to 2.5.

[0046] In a preferred embodiment, the filtrate contains lithium, nickel, manganese and cobalt in amounts suitable for recovery, and is substantially free of aluminum, copper and iron, e.g., containing less than 10 ppm, preferably less than 5 ppm aluminum, iron and / or copper. A suitable technique for determining such amounts is inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0047] The methods disclosed herein result in more efficient removal of iron and aluminum while minimizing co-precipitation of the valuable NMC metals, nickel, manganese and cobalt. At the same time, the methods result in the production of a lithium-rich filtrate that is substantially free of copper, iron and aluminum and is therefore suitable for both precipitation of NMC metals and recovery of lithium. EXAMPLES

[0048] Example 1: Precipitation of Al and Fe phosphates in one step The leachate (X), from which substantially all of the copper has been removed, is directed to a precipitation unit 100, as shown diagrammatically in FIG. 2. In this example, the flow rate of the leachate is about 60 L / h and the initial pH of the leachate is about 0.5. In a first step, 85% phosphoric acid (H 3 PO 4 The pH is adjusted to about 2.5 by addition of sodium hydroxide (NaOH, solid) and sodium hydroxide (NaOH, solid). The leachate is collected in a settling tank 200 where seeds (Al and Fe phosphate crystals) are added to a concentration of about 0.1 g / L. The residence time in the first settling tank is at least 70° C. and preferably about 24 hours, after which the contents are directed to a separation unit 300, e.g. a filter, for separation into a precipitate and a filtrate (Y). The precipitate is directed to a washing unit 310 where the FePO 2 containing traces of co-precipitated Li and NMC is washed. 4 and AlPO 4 A washed precipitate (Z) of

[0049] Example 2: Precipitation of Al and Fe phosphates in two steps The leachate (I), from which substantially all the copper has been removed, is directed to a precipitation unit 100, as shown diagrammatically in FIG. 3. In this example, the flow rate of the leachate is about 60 L / h and the initial pH of the leachate is about 0.5. In a first step, 85% phosphoric acid (H 3 PO 4 The pH is adjusted to about 2.5 by addition of sodium hydroxide (NaOH, solid) and sodium hydroxide (NaOH, solid). The leachate is collected in a first settling tank 200 where seeds (Al and Fe phosphate crystals) are added to a concentration of about 0.1 g / L. The residence time in the first settling tank is at least 70° C. and preferably about 24 hours, after which the contents are directed to a separation unit 300, e.g. a filter, for separation into a precipitate and a filtrate.

[0050] The precipitate is led to a washing unit 310, where it is washed with FePO containing traces of coprecipitated Li and NMC. 4 and AlPO 4 A washed precipitate (II) of 0.1% is obtained, as well as a filtrate (III), which is preferably recycled, for example by directing it to a leaching unit (not shown) upstream of the recycling process.

[0051] The pH of the filtrate from the precipitation tank 200 and separation unit 300 is adjusted to about 5 in unit 400, for example by adding NaOH, and is led to a second precipitation tank 500. The residence time in the second precipitation tank is at least 70° C. and preferably about 24 hours. Optionally, seeds (Al and Fe phosphate crystals) are added to a concentration of about 0.1 g / L. The contents of the second precipitation tank are then led to a separation unit 600, for example a filter, to obtain a lithium-rich filtrate (IV) free of Cu, Al and Fe, and a solid precipitate. This precipitate is preferably washed in unit 610 to obtain a washed solid precipitate (VI) containing the remaining Al and Fe and co-precipitated Ni, Mn and Co, and a filtrate (VII), which is recycled to wash the Al and Fe phosphate precipitate in unit 310.

[0052] The Al-Fe precipitate was prepared by the addition of NaOH and H 3 PO 4The method is formed using only bulk chemicals such as FePO and no organic solvents, producing an aqueous stream rich in NMC that is substantially free of Cu, Al and Fe. 4 and AlPO 4 The main precipitate consists of FePO with minor amounts of co-precipitated Ni, Mn and Co. 4 and AlPO 4 Two precipitate streams are formed: a primary precipitate stream containing the primary precipitate and a secondary precipitate containing coprecipitated Ni, Mn and Co. With an inlet stream of 60 L / hr of leachate of typical composition in a battery recycling process, an estimated 60 L / hr of lithium rich leachate / filtrate can be obtained. The primary precipitate stream is about 1.5 kg / hr and the secondary precipitate stream is 0.3 kg / hr, and it can be seen that the primary precipitate is actually Al and some phosphates.

[0053] In the washing unit 610, an acidic aqueous solution is preferably added and the filtrate is directed to the washing unit 310. Water consumption is minimized since the filtrate from the unit 310 is recycled to the upstream units of the recycle / recovery process. The estimated flows are shown in Table 3:

[0054] [Table 3]

[0055] In an industrial scale process, the copper-free first leachate is typically added in an amount of 40 000-80 000 L / h, for example 50 000-70 000 L / h, preferably 55 000-65 000 L / h. In the first precipitation step, phosphoric acid H 3 PO 4 is usually added to the first leachate in an amount of 500 to 2500 kg / hour, for example 1000 to 2000 kg / hour, preferably 1250 to 1750 kg / hour, until the pH reaches about 2.5.

[0056] In the second precipitation step, NaOH is typically added to the first leachate in an amount of 250-1500 kg / h, for example 500-1000 kg / h, preferably 700-800 kg / h, to adjust the pH to about 5 for the second precipitation.

[0057] In another example where the first leachate from the black mass contains copper, the copper can be removed after removal of the aluminum and iron, for example by precipitation or solvent extraction.

[0058] The method disclosed herein has several advantages: Precipitation of Al and Fe in the form of phosphates minimizes co-precipitation of lithium and NMC metals, and furthermore, Al and Fe phosphates are easier to filter and the precipitates formed are easier to wash than, for example, the corresponding hydroxide precipitates.

[0059] In addition, the method is very flexible and can handle black mass leachates containing varying amounts of aluminum and iron due to the efficient removal of aluminum and iron at an early stage. This is particularly advantageous since large-scale recovery of rechargeable lithium-ion batteries involves handling black masses of various compositions. The method disclosed herein ensures efficient recovery of NMC metals and lithium even when the initial leachate composition changes.

[0060] Example 3: Evaluation of precipitation yields of major elements as phosphates at different pH values The stoichiometric H required for ideal precipitation of iron and aluminum 3 PO 4 A volume equivalent to a 10% excess over (pure) was added to a specific volume of leachate and mixed for 30 minutes (in this case, approximately 60 mL of stock solution was prepared, which was 4.52 mL of 85% H 3 PO 4 to 55 mL of leachate, which is equivalent to 82 mL of acid per liter of leachate).

[0061] This solution was then poured into small glass vials, 5 mL per vial, and 700 g / L NaOH was then slowly added to raise the pH of the solution, ideal for precipitating the iron and aluminum along with the phosphates present in the solution.

[0062] The experiments were carried out in 20 mL glass vials at room temperature of 22° C. To ensure complete mixing and reaction of the compounds under investigation, the solutions were stirred for 2 h after addition of NaOH.

[0063] Table 4 and Figure 4 summarize the results of experiments performed at different pH values ​​with various amounts of NaOH added, and the composition of the solutions measured by inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0064] [Table 4]

[0065] The precipitation yields of P are consistent with those of Fe and Al as a result of the formation of iron-aluminum phosphate precipitates. A 10% excess of phosphorus is sufficient to precipitate Fe and Al at a pH below 3.5 and is selective to the remaining elements.

[0066] Without further elaboration, it is believed that one skilled in the art can utilize the present invention to its fullest extent using the present specification, including the examples, and while preferred embodiments have been described herein which constitute the best mode currently known, it should be understood that various changes and modifications, as would be apparent to one of ordinary skill in the art, can be made without departing from the scope of the present invention as set forth in the appended claims.

[0067] Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those of skill in the art. The various aspects and embodiments disclosed herein are intended to be illustrative and not limiting, with the true scope and spirit being indicated by the following claims. The invention as originally claimed is set forth below. [1] A method for removing aluminum and iron in recycling rechargeable batteries, comprising: a) preparing an exudate from the black mass; b) adding phosphoric acid (H 3 PO 4 ) is added, c) Adjust the pH to iron phosphate (FePO 4 ) and aluminum phosphate (AlPO 4 ) to form d) The formed FePO 4 and AlPO 4 and e) forming a filtrate for recovering the cathode metal. A method comprising: [2] The method according to [1], wherein the rechargeable battery is a rechargeable lithium ion battery. [3] The method according to [1] or [2], wherein the precipitation is carried out in two steps with different pH levels. [4] The method according to [3], wherein in the first precipitation step, the pH is adjusted to 1.5 to 4, for example 1.5 to 3.5, preferably 1.5 to 3. [5] The method according to [3] or [4], wherein in the second step, the pH is adjusted to 2.5 to 6.5, for example 2.5 to 6, preferably 2.5 to 4. [6] In the first precipitation step, a seed crystal is added to form FePO 4 and AlPO 4 The method according to any one of [3] to [5], wherein the compound is precipitated. [7] The method according to [6], wherein the seed crystals contain aluminum and iron phosphate crystals, and the seed crystals are added in an amount of 0.05 to 0.3 g / L, for example 0.05 to 0.2 g / L, preferably 0.05 to 0.15 g / L. [8] The method according to any one of [4] to [7], wherein the first and second precipitation steps are carried out at 20 to 95°C, for example, 55 to 95°C, for example, 55 to 85°C, preferably 65 to 75°C. [9] The method according to any one of [4] to [8], wherein the residence time of each of the precipitation steps is 2 to 24 hours, for example 12 to 18 hours, for example 2 to 12 hours, preferably 2 to 6 hours.

[10] The first precipitation step contains a larger amount of FePO than the second precipitation step. 4 and AlPO 4 The method according to any one of [4] to [9], wherein the compound is precipitated.

[11] FePO 4 and AlPO 4 The method according to any one of [1] to

[10] , wherein the precipitate containing the compound is washed with an aqueous solution having a pH of 1.5 to 5.5, preferably 1.5 to 2.5.

[12] The method according to any one of [1] to

[11] , wherein the filtrate contains lithium, nickel, manganese and cobalt, and less than 10 ppm, for example less than 5 ppm, of aluminum, iron and / or copper.

[13] The method according to any one of [1] to

[12] , wherein the leachate from the black mass in step a) is substantially free of copper.

[14] The method according to any one of [1] to

[12] , wherein copper is recovered following the removal of aluminum and iron.

[0068] Itemized list of aspects This is an itemized list of aspects of the present invention: 1. A method for removing aluminum and iron in recycling rechargeable lithium ion batteries, comprising: a) extracting copper from a leachate from the black mass to produce a first leachate; b) The leachate from step a) is treated with phosphoric acid (H 3 PO 4 ) is added, c) Adjust the pH to iron phosphate (FePO 4 ) and aluminum phosphate (AlPO 4 ) to form d) The formed FePO 4 and AlPO 4 and e) forming a filtrate for recovering the cathode metal. A method comprising: 2. The method according to item 1, wherein the precipitation is carried out in two steps with different pH values. 3. The method according to item 2, wherein the pH in the first precipitation step is adjusted to 1.5 to 4, for example, 1.5 to 3.5, and preferably 1.5 to 3, and the pH in the second step is adjusted to 3 to 6.5, for example, 3 to 6, and preferably 3 to 5.5. 4. In the first precipitation step, seed crystals are added to prepare FePO 4 and AlPO 4 Item 4. The method according to Item 2 or 3, wherein the compound is precipitated. 5. The method according to item 4, wherein the seed crystals include aluminum and iron phosphate crystals, and the seed crystals are added in an amount of 0.05 to 0.3 g / L, for example 0.05 to 0.2 g / L, preferably 0.05 to 0.15 g / L. 6. The method according to any one of items 3 to 5, wherein the precipitation step is carried out at 55 to 95°C, for example 55 to 85°C, preferably 65 to 75°C. 7. The method according to any one of items 3 to 6, wherein the residence time of each precipitation step is 2 to 24 hours, for example, 2 to 12 hours, and preferably 2 to 6 hours. 8. The first precipitation step produced a larger amount of FePO than the second precipitation step. 4 and AlPO 4 The method according to any one of items 3 to 7, wherein the compound is precipitated. 9.FePO 4 and AlPO 4The method according to any one of the preceding paragraphs, wherein the precipitate containing is washed with an aqueous solution having a pH of 1.5 to 5.5, preferably 1.5 to 2.5. 10. The method of any one of the preceding claims, wherein the filtrate contains lithium, nickel, manganese and cobalt, as well as less than 10 ppm, such as less than 5 ppm, of aluminium, iron and / or copper.

Claims

1. 1. A method for removing aluminum and iron in recycling rechargeable batteries, comprising: a) preparing an exudate from the black mass; b) adding phosphoric acid (H ３ P.O. ４ ) is added, c) Adjust the pH to iron phosphate (FePO ４ ) and aluminum phosphate (AlPO ４ ) forming a d) the formed FePO ４ and AlPO ４ and e) forming a filtrate for recovering the cathode metal. A method comprising:

2. The method of claim 1 , wherein the rechargeable battery is a rechargeable lithium ion battery.

3. 3. The method according to claim 1 or 2, wherein the precipitation is carried out in two steps with different pH.

4. 4. The process of claim 3, wherein in the first precipitation step the pH is adjusted to between 1.5 and 4.

5. 5. The method according to claim 3, wherein in the second step the pH is adjusted to between 2.5 and 6.

5.

6. In the first precipitation step, a seed crystal is added to precipitate FePO ４ and AlPO ４ The method of claim 4, wherein the

7. 7. The method of claim 6, wherein the seeds comprise aluminum and iron phosphate crystals and the seeds are added in an amount of 0.05 to 0.3 g / L.

8. 8. The process according to any one of claims 4 to 7, wherein the first and second precipitation steps are carried out at 20 to 95°C.

9. 9. The process according to any one of claims 4 to 8, wherein the residence time of each precipitation step is from 2 to 24 hours.

10. The FePO ４ and AlPO ４ The method according to any one of claims 1 to 9, wherein the precipitate containing is washed with an aqueous solution having a pH of 1.5 to 5.

5.

11. 11. The method of any one of claims 1 to 10, wherein the filtrate comprises lithium, nickel, manganese and cobalt, and one or more of aluminum, iron or copper is less than 10 ppm.

12. The method according to any one of claims 1 to 11, wherein the leachate from the black mass in step a) is substantially free of copper.

13. A method according to any one of claims 1 to 11, wherein the removal of aluminium and iron is followed by recovery of copper.

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