AU2023241377A1 - Battery recycling - Google Patents

Abstract

The present invention provides a method for obtaining a cobalt-enriched material, comprising: (a) providing a discharged lithium ion cell comprising cobalt; (b) crushing the cell to form fragments; (c) separating the fragments to obtain particles of less than 4 mm in size; and (d) treating the obtained particles with a magnetic field of between 2000 and 8000 Gauss, so as to select cobalt-enriched material from non-cobalt-enriched material, wherein the method does not comprise a heat treatment, as well as a product obtained from the method, and an apparatus for carrying out the method. 1/1 25 23.77wt% 21.38wt% 20 18.6wt% 15 13wt% 10 5 0 Em Em El Sieve 1 Sieve 2 Sieve 3 Original black mass ELi ECo *Ni Mn FIGURE 1 1000 G 2000 G 3000 G 5000 G The Gaussian intensity of the magnetic separation FIGURE 2

Description

1/1

23.77wt% 21.38wt% 18.6wt%

13wt%

Em Em El Sieve 1 Sieve 2 Sieve 3 Original black mass

ELi ECo *Ni Mn

FIGURE 1

1000 G 2000 G 3000 G 5000 G

The Gaussian intensity of the magnetic separation

FIGURE 2

BATTERY RECYCLING

Related Application

[0001] The present application claims priority from Australian Provisional Patent Application No. 2022902909 filed on 6 October 2022, the entire contents of which is hereby incorporated by reference.

Field

[0002] The present invention relates to the field of battery recycling. More particular, this invention relates to a method and apparatus for processing cobalt-containing batteries and recovering a cobalt-enriched product. However, it will be appreciated that the invention is not limited to this particular field of use.

Background

[0003] The following discussion of the prior art is provided to place the invention in an appropriate technical context and enable the advantages of it to be more fully understood. It should be appreciated, however, that any discussion of the prior art throughout the specification should not be considered as an express or implied admission that such prior art is widely known or forms part of the common general knowledge in the field.

[0004] As developed economies transition away from non-renewable or "fossil" sources of energy, the need for storing energy is rapidly increasing. Batteries based on lithium ions are currently the preferred option, as they provide a number of advantages over other chemistries, such as fast recharging, a high power density and being lightweight, making them suitable for a range of applications. For instance, there is a rising demand for electric and hybrid electric vehicles, where lithium-ion batteries are used extensively. Accordingly, the use of lithium-based batteries is growing at an increasing rate.

[0005] However, it is also known that batteries have a limited lifespan, with repeated charge discharge cycles degrading the battery components, generally through side reactions that limit the "free" ions in the battery or by introducing structural disorder, which reduces the capacity and lifetime of the battery. The market forecast of lithium ion battery recycling or resource recovery as projected to be US$10.7 billion by 2026, with a compound annual growth rate of about 24.8% during 2021-2026. The increasing use of lithium ion batteries results in a price hike for the raw battery materials such as cobalt and lithium, thus making battery recycling or recovery industries increasingly more profitable. In addition, limited availability of the raw materials used in lithium ion battery manufacturing and high demand from various end-use applications fuels the market for lithium ion battery recycling and resource recovery.

[0006] Currently, batteries rely on metallic elements that are a finite resource obtained by mining and may be environmentally damaging if disposed of in landfill. Therefore, it would be advantageous to be able to recover such materials from batteries that are no longer useful, so that they can be re-used in new batteries or for other applications. However, there are limited commercially-beneficial processes for recovering resources from spent lithium ion batteries.

[0007] Accordingly, there is a need for a suitable method for processing spent lithium ion batteries and recovering metallic elements from them. Preferably, the method would be at least one of low cost, have low energy consumption, efficient and easy to operate.

[0008] In one aspect, it is an object of the present invention that at least one of the needs above is at least partially satisfied.

[0009] In another aspect, it is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least provide a useful alternative.

Summary of Invention

[00010] In one embodiment, the present invention aims to address at least one of the deficiencies of current processes for recycling and/or recovering resources from batteries. In particular, in one embodiment the present invention aims to reduce the costs (both in terms of energy and financial costs) of recovering valuable metals from used lithium ion batteries. More particularly, in one embodiment the present invention aims to produce a cobalt-enriched material from spent lithium ion batteries, which can then be used to produce new batteries, or other useful materials. Advantageously, in some embodiments the present invention achieves these aims without the use of a heating step, thereby saving significant energy costs.

[00011] In a first aspect of the present invention, there is provided a method for obtaining a cobalt-enriched material, comprising: (a) providing a discharged lithium ion cell comprising cobalt; (b) crushing the cell to form fragments; (c) separating the fragments to obtain (or provide) particles of less than 4 mm in size; and (d) treating the obtained (or provided) particles with a magnetic field of between 2000 and 8000 Gauss, so as to select cobalt-enriched material from non-cobalt-enriched material, wherein the method does not comprise a heat treatment.

[00012] The following options may be used in conjunction with the first aspect, either individually or in any suitable combination.

[00013] The lithium ion cell may be any suitable electrolysis cell or galvanic cell that comprises lithium ions. For example, the cell may be located in a lithium ion battery, or it may be located in a fuel cell, electrolysis device, or the like. In one preferred embodiment, the cell is located in a lithium ion battery.

[00014] The fragments formed in step (b) includes the particles defined in step (c) and may also include larger or smaller pieces or parts of the cell. In other words, "fragments" encompasses all solid parts of the cell obtained following the crushing of step (b).

[00015] The particles obtained from the separating step (step (c)) may be less than about 4 mm in size, or less than about 3 mm, or less than about 2 mm, or at least about 1.5 mm, or less than about 1.2 mm, or less than about 1 mm. For example, the particles that are obtained may be between about 30 m and about 4 mm, or between about 45 m and 3 mm, or between about 63 m and about 1.2 mm, or between about 100 m and about 2.5 mm, or between about 250 m and 1 mm, or they may be any other suitable subrange.

[00016] Any suitable or appropriate separating method or device may be used in the separating step (step (c)) to obtain the particles of a certain size. As the skilled person would appreciate, whilst particles can be separated on the basis of a range of physical properties (such as, for example, size, density, conductivity or floatation), in order to obtain particles within a defined size range, it is preferred that size-based methods or devices by employed in the present invention. In some embodiments, the present invention may use one or more sieves to obtain a fraction within a size range as defined herein. For example, one, two, three, four or more sieves may be used to obtain particles of a certain size. In one embodiment, two sieves are used, whereby one sieve defines an upper range of particle size (and so the particles that pass through the sieve are collected) and the second sieve defines the lower range of particle size (and so the particles that are retained in the sieve are collected).

[00017] The magnetic field that is applied in the treating step may be between 2000 Gauss and 8000 Gauss, or it may be any subrange therein. For example, it may be between about 3000 and 5000 Gauss, or between about 2500 Gauss and 7500 Gauss, or between about 4000 and 6000 Gauss, or it may be about 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500, 4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000, 6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500, 7600, 7700, 7800, 7900, or 8000 Gauss, or any range therein. The magnetic field may be provided by any suitable device. In some embodiments, the magnetic field may be provided by a magnetic separator, which comprises a magnet (either a permanent magnet or an electromagnet) a barrier between the magnet and the particles (such as, for example, a drum or a plate), and two or more collection bins or areas for separating the particles based on the strength of their interaction with the magnetic field. In one embodiment, the magnetic separator is a rotating shaft drum. Preferably, the rotating shaft drum has a diameter of less than about 30 cm, such as between about 15 cm and 30 cm, or between about 20 cm and 25 cm, or about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 cm. In other embodiments, the magnetic field is provided by an eddy current separator, whereby the separation of the particles is based on their interaction with an eddy current (which is generally useful for separating conductive non-ferrous metals from non-conductive particles), whereby conductive particles are ejected from the particle stream (usually a conveyor belt or the like) and non-conductive particles pass through unaffected. In some embodiments, both a magnetic separator and an eddy current separator may be used in series, whereby the magnetic field separator removes ferrous materials (that may damage an eddy current separator, as ferrous materials heat up in an eddy current) and the eddy current separator separates conductive, less magnetic materials (such as cobalt).

[00018] In some embodiments, the treatment step (step (d)) further comprises an optional electrostatic separation device, which also separates particles on the basis of conductivity differences, albeit with electrostatic attractive forces rather than interaction in a magnetic field or eddy current. The electrostatic separator may be used to treat the particles obtained after treatment with a magnetic separator or after treatment with an eddy current separator.

[00019] The method of the present invention may further comprise an optional step of treating the fragments obtained from step (b) with a solvent before treatment with a magnetic field in step (c). As the skilled person would appreciate, electrodes may comprise a polymer binder, whereby removal of at least a portion of the polymer binder before particle separation may increase the recovery of valuable metals from the electrodes. Accordingly, any solvent that at least partially dissolves or degrades the polymer binder may be suitable for this optional step. In some embodiments, the polymer binder may be polyvinylidene fluoride (PVDF). In such embodiments, suitable solvents may be selected from dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc) or mixtures thereof. In one preferred embodiment, the solvent is NMP.

[00020] In one embodiment of the present invention, one or more, or all, of the steps (a), (b), (c) and (d) of the first aspect is performed at room temperature, that is, a temperature of from about 10 to 35 °C; especially between about 15 to 30 °C, or about 20 to 25 °C.

[00021] In a second aspect of the present invention, there is provided a product obtained, or obtainable, from the method of the first aspect.

[00022] In a third aspect of the present invention, there is provided an apparatus for obtaining a cobalt-enriched material from a discharged lithium ion cell comprising cobalt, the apparatus comprising: a crushing device; a sieving device and a magnetic device; wherein the sieving device is adapted to obtain particles of less than 4 mm in size, the magnetic device is adapted to generate a magnetic field of between 2000 and 8000 Gauss, and the apparatus does not include a heating device. The terms "crushing device", "sieving device", and "magnetic device" are as described herein.

Brief Description of Drawings

[00023] Figure 1: Determination of Lithium, Cobalt, Nickel and Manganese in Black Powder by ICP-MS.

[00024] Figure 2: The Gaussian intensity of magnetic separation from 1000G to 5000G.

Definitions

[00025] The following definitions are provided to enable the skilled person to better understand the invention disclosed herein. These are intended to be general and are not intended to limit the scope of the invention to these terms or definitions alone. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains.

[00026] As used herein, the terms "recycling" and "recovery" or "resource recovery" (and variations thereof) may be used interchangeably. As the skilled person would appreciate, "recycling" commonly refers to a process of converting waste materials into new materials or objects (such as the recycling of waster plastic bottles into new bottles or other polymer-based objects), which may refer to a portion of the waste material or the entirety of the waste material. As the process of the present invention is directed to the specific recovery of a portion of the waste cell or battery, the term "recovery" or "resource recovery" may also apply; for example, the cobalt-enriched materials may be "recycled" following "recovery" of this material from the waste.

[00027] As used herein, the term "spent" (when used in reference to a cell or a battery, such as "a spent battery") refers to a battery or a cell that has exceeded its useful lifetime, no longer maintains a charge sufficient for its intended use, or has degraded sufficiently to require disposal, reclamation or recycling.

[00028] As used herein, the term "fragment" or "fragments" means a part or parts broken off from a larger thing, or the resulting material after a large thing is broken into smaller parts. It is also meant that other terms such as "particles", "pieces", "portions" and the like fall within the meaning of "fragments".

[00029] As used herein, the term "comprising" means "including". Variations of the word "comprising", such as "comprise" and "comprises", have correspondingly varied meanings. As used herein, the terms "including" and "comprising" are non-exclusive. As used herein, the terms "including" and "comprising" do not imply that the specified integer(s) represent a major part of the whole.

[00030] The transitional phrase "consisting of' excludes any element, step, or ingredient not specified. If in the claim, such would close the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase "consisting of' appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[00031] The transitional phrase "consisting essentially of' is used to define a composition, process or method that includes materials, steps, features, components, or elements, in addition to those literally disclosed, provided that these additional materials, steps, features, components, or elements do not materially affect the basic and novel characteristic(s) of the claimed invention. The term "consisting essentially of'occupies a middle ground between "comprising" and "consisting of'.

[00032] Where applicants have defined an invention or a portion thereof with an open-ended term such as "comprising", it should be readily understood that (unless otherwise stated) the description should be interpreted to also describe such an invention using the terms "consisting essentially of' or "consisting of. " In other words, with respect to the terms "comprising", ''consisting of', and "consisting essentially of', where one of these three terms are used herein, the presently disclosed and claimed subject matter may include the use of either of the other two terms. Thus, in some embodiments not otherwise explicitly recited, any instance of "comprising" may be replaced by "consisting of' or, alternatively, by "consisting essentially of'.

[00033] Further, unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[00034] Also, the indefinite articles "a" and "an" preceding an element or component of the invention are intended to be non-restrictive regarding the number of instances (i.e., occurrences) of the element or component. Therefore "a" or "an" should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.

[00035] The terms "predominantly" and "substantially" as used herein shall mean comprising more than 50% by weight, unless otherwise indicated.

[00036] Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term "about". As used herein, the terms "about" and "approximately" are understood to refer to the range of -10% to +10% of the referenced number, preferably -5% to +5% of the referenced number, more preferably -1 % to + 1 % of the referenced number, most preferably -0.1 % to +0.1 % of the referenced number. Moreover, with reference to numerical ranges, these terms should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from Ito 8, from 3 to 7, from I to 9, from 3.6 to 4.6, from 3.5 to 9.9, from 8 to 10, and so forth.

Abbreviations

[00037] The following abbreviations are used herein in relation to battery chemistries:

LCO: Lithium Cobalt oxide

LNO: Lithium Nickel oxide

NCA: Lithium Nickel Cobalt Aluminium oxide

NMC: Lithium Nickel Manganese Cobalt oxide

LMO: Lithium Manganese oxide

LFP: Lithium Iron Phosphate

LTO: Lithium Titanate

[00038] The following abbreviations are also used herein:

ICP-MS: Inductively Coupled Plasma Mass Spectroscopy

PVDF: Polyvinylidene fluoride

DMF: dimethyl formamide

DMSO: dimethyl sulfoxide

NMP: N-methyl-2-pyrrolidone

DMAc: dimethylacetamide

Description of Embodiments

[00039] The following description conveys exemplary embodiments of the present invention in sufficient detail to enable those of ordinary skill in the art to practice the present invention. Features or limitations of the various embodiments described do not necessarily limit other embodiments of the present invention or the present invention as a whole. Hence, the following detailed description does not limit the scope of the present invention, which is defined only by the claims.

[00040] The present invention relates to a method for processing used batteries to recover valuable metals, especially cobalt.

[00041] In particular, the inventor has developed a method for processing cobalt-containing batteries which allows for the efficient recovery of cobalt, whereby other metals (such as iron, aluminium and copper) are separated from the cobalt. As will be described in more detail below and with reference to the Examples, the method of some aspects of the present invention has been developed to be an efficient process that utilises relatively low-cost components that are efficient to operate. In some aspects the method of the present invention advantageously avoids the use of a heat treatment step that is common in known processes, but which is energy intensive and increases the costs of carrying out such recovery processes. Although the present invention has been developed with the intention of recycling lithium ion batteries, it is anticipated by the inventor that this process may be suitable for recovering cobalt from batteries and cells based on alternative chemistries.

Batteries

[00042] As the skilled person would appreciate, current batteries are based on a range of anodic and cathodic chemistries. For instance, although "lithium ion" batteries all utilise mobile lithium ions, the chemistry of the anode and cathode can vary, which has an effect on the power output, safety, lifetime and cost of a battery. Table 1 below summarises the various anode and cathode materials found in lithium ion batteries, whereby the relative power, safety and lifetime are provided by the scale: -- < - < 0 <+ <++ <+++.

Table 1: Comparison of lithium ion battery components.

Name LCO LNO NCA NMC LMO LFP LTO

(Nio.sCo L(Nio.33Mno.33e.g., Cathode LiCoO 2 LiNiO 2 LiMn 20 4 LiFePO 4 LMO, Oo.1Alo.o 5)0 2 Coo.33)02 NCA Anode Graphite Graphite Graphite Graphite Graphite Graphite Li 4 Ti5 OI 2 Cell 3.7-3.9V 3.6V 3.65V 3.8-4.0V 4.0V 3.3V 2.3-2.5V voltage Energy 150 150 120 130 85 130 mAh/g 170 mAh/g Density mAh/g mAh/g mAh/g mAh/g mAh/g Power + 0 + 0 + + ++

Safety -0 0 0 + ++ ++

Lifetime - 0 + 0 0 + +++

Cost -- + 0 0 + + 0

[00043] As will be described in more detail below, in some embodiments the method of the present invention is particularly suitable for recovering cobalt from batteries with LCO, NCA, NMC and suitable LTO lithium ion batteries.

Recovery Method

[00044] At present, typical recycling processes for waste lithium ion batteries generally include the steps of a discharge treatment and then physical processing to obtain the anode and cathode materials (known in the art as "black powder"). This black powder is usually then processed via heat treatment (pyrometallurgy) to obtain the valuable metals in the black powder, before the remaining materials are disposed of. Without wishing to be bound by theory, the inventor has found that the use of magnetic separation on particles of a certain size effectively separate the elements of the black powder without the need for a pyrometallurgical process.

[00045] In one embodiment of the present invention, there is provided a method for obtaining a cobalt-enriched material, comprising: (a) providing a discharged lithium ion cell comprising cobalt; (b) crushing the cell to form fragments; (c) separating the fragments to obtain (or provide) particles of less than 4mm in size; and (d) treating the obtained (or provided) particles with a magnetic field of between 2000 and 8000 Gauss, so as to select cobalt-enriched material from non-cobalt-enriched material, wherein the method does not comprise a heat treatment.

[00046] The lithium ion cell may be found within a battery, or it may be another electrochemical cell (e.g., an electrolysis cell or a galvanic cell, for instance). The lithium ion cell comprises cobalt (for example, it may be a battery with LCO, NCA, NMC or suitable LTO chemistry). Preferably, the lithium ion cell comprises cobalt in either the anode material, the cathode material, or both.

[00047] The lithium ion cell is discharged before processing in this method. As the skilled person will appreciate, batteries are commonly discharged before mechanical processing, to reduce the risks of fire and explosions that can occur, given the high voltages and reactive components commonly found in spent lithium ion batteries. Discharging can reduce this risk by reducing the electrochemical potential of the cell or battery. In some embodiments, the cell may be fully, substantially or partially discharged, provided it is sufficiently discharged for processing.

[00048] The discharged lithium ion cell is then crushed to produce fragments. Any suitable mechanical process can be used to crush the cell, so long as the outer casing (if any) is ruptured and the contents of the interior (including, for example, the electrolyte, the anode material, the cathode material, wiring, supporting structures and control structures) are exposed. The fragments obtained from the crushing step may comprise any solid features of the cell or battery, such as the anode material, cathode material, casing and other internal components. In a preferred embodiment, the anode and cathode materials are rendered to form particles in this step (that is, the fragments comprise particles of the anode and/or cathode materials). As the skilled person would appreciate, it is the cathode and/or the anode material (depending on the specific chemistry employed by the battery) that contains the majority of the recoverable valuable metals, such as cobalt. It is therefore preferred that the electrode material is reduced in size to form particles in the crushing step. In other embodiments, a further processing step is required after crushing the discharged cell or battery in order to form particles from the electrode materials.

[00049] After the crushing step, the method of the present invention requires a step of separating the fragments obtained from the crushing step. The inventors have surprisingly found that particles of a certain size are particularly suitable for obtaining an enriched cobalt product from a used lithium ion cell or battery. Particularly suitable sizes for the particles are less than about 4 mm, or less then about 3 mm, or less than about 2 mm, or less than about 1.5 mm, or less than about 1 mm, or any range therein, such as between about 30 m and about 4 mm, or between about 45 m and 3 mm, or between about 63 m and about 1.2 mm, or between about 100 m and about 2.5 mm, or between about 250 m and 1 mm, for example.

[00050] Any suitable separation method may be suitable for obtaining (or providing) particles of a particular size range as described herein. The inventors have found that a suitably efficient and low-cost option is to use one or more sieves of particular sizes which allow for the rejection of particles that all outside the range of the particles desired by the user. For example, a sieve with a 4 mm aperture may be used to remove larger particles and other materials, whereby the material that passes through the 4 mm sieve is collected. If a particular particle size range is desired, these sieved particles may then be sorted using a fine mesh sieve, whereby the material that is retained by the sieve is collected. It is anticipated that the skilled can optimise this separation process in order to obtain the particles that are desired for further processing.

[00051] The particles of a particular size that are obtained following separation from the waste materials are then exposed to a magnetic field. The magnetic field may be between about 2000 Gauss and about 8000 Gauss, such as between about 3000 and 5000 Gauss, or between about 2500 Gauss and 7500 Gauss, or between about 4000 and 6000 Gauss, or any range therein. The magnetic field may be provided by any suitable device. In one embodiment, the magnetic field is provided by a magnetic separator so as to separate ferromagnetic and strongly paramagnetic particles from particles that are weakly paramagnetic or non-metallic. The magnetic separator may be any suitable conventional apparatus, such as for example, a permanent magnetic drum separator or a cross-belt separator. Such conventional apparatus for the separation of ferromagnetic and strongly paramagnetic particles would be well-known to the skilled person.

[00052] The magnetic field may optionally also, or instead, be provided by an eddy current separator. As the skilled person would be aware, eddy current separation processes utilise eddy currents to separate particles. This technique is commonly used to separate non-ferrous metals from non-metals, whereby the particles are passed along a conveyor belt to an eddy current rotor, resulting in the non-ferrous metal particles being caught in an eddy current and caught in a product bin, while the non-metal particles that do not interact with the eddy current fall off the belt. In one particular embodiment, the eddy current separator is used after a magnetic separator, as the presence of ferrous particles in an eddy current separator can damage the separator (since ferrous materials heat up when exposed to an eddy current).

[00053] Step (d) of the method of the present invention may optionally further comprise use of an electrostatic separator. As the skilled person would appreciate, an electrostatic separator may also be used to separate particles based on differing electrostatic charges. Such electrostatic separators would be known to the skilled person.

[00054] Each of the abovementioned magnetic, eddy current and electrostatic separators may, in some embodiments, employ a rotating drum, whereby a permanent magnet or electromagnet are employed inside the drum, and particles that are attracted to the magnetic field are attracted to the surface of the drum and hence separated from particles that are not attracted to the magnetic field, or particles with an electrostatic charge are attracted to the drum and other conditions, such as an ionizing discharge, disrupt the electrostatic attraction to the drum of a subset of those particles. In such apparatus, the drum may be no more than about 30 cm in length, which the inventor has found to be useful in the present invention. In some embodiments, the rotating drum of a magnetic separator, and/or an eddy current separator, and/or an electrostatic separator may be between about 15 and 30 cm, or between about 20 and 25 cm, or between about 10 and 20 cm, or between about 25 and 30 cm.

[00055] The method of the present invention may include an optional additional processing step of exposing the particles obtained from the crushing step to a solvent. As the skilled person would appreciate, electrodes that are used in lithium ion cells and batteries generally comprise:

(1) an aluminium substrate (e.g., aluminium foil); (2) the active material (e.g., the lithium containing material); (3) a conductive additive (added to increase conductivity); and (4) a binder. The binder may be a polymer. The polymer binder, when used, must be a robust polymer, as it may be in contact with the electrolyte (which frequently comprises a combustible solvent) and may be exposed to many heating and cooling cycles (as heat is generated during recharging and discharging of a battery or use of a cell). An example of a common polymer binder is PVDF, which is a robust polymer that is resistant to a range of solvents, acids and hydrocarbons. However, PVDF can be dissolved or degraded by some solvents. Any solvent that is suitable for dissolving or degrading PVDF may be suitable for use in this optional step. Examples of suitable solvents include DMF, DMSO, NMP or DMAc. One particularly suitable solvent is NMP.

[00056] In one embodiment, the result of the method described herein is the selective enrichment of particles that comprise cobalt. Put differently, impurities present in lithium ion cells and batteries such as, for example, iron, aluminium, copper, lithium and graphite, are removed from the obtained product by use of the present method, thereby resulting in the relative enrichment of cobalt in the particles that are obtained.

[00057] Surprisingly, the method developed by the inventor does not require a heating step. Industrial recycling and recovery processes for metallic elements commonly utilise a heating step, usually under reducing conditions, to convert metallic ions into their elemental form. However, the inventor has shown that such a step is not necessary in order to recover a cobalt enriched portion of the lithium ion cell or battery that is processed. Without wishing to be bound to theory, it is expected that this is due to the particular separation steps that are employed, whereby some impurities are removed through size exclusion (for example, large portions of the casing and internal components, such as aluminium foil used in the cathode or copper wiring used to complete the circuit) and other impurities are removed based on their interaction (or lack thereof) with a magnetic field and/or eddy current and/or electrostatic charge (such as the graphite of the anode, which is non-magnetic).

[00058] Accordingly, as the only processes required by the method of the present invention including crushing, sieving, and magnetic separation (which can be applied by using permanent magnets), the energy consumption of the method may be relatively low. In other words, by developing a process that does not require a heating step (which is energy intensive) and can avoid the use of a strong electromagnet (in some embodiments), the inventor has advantageously developed a process with relatively low energy consumption. Further, the processes of the present method utilise equipment that are commonly obtained and also relatively simple to operate, thereby meaning that the costs of installation, operation and maintenance are also relatively low, leading to a commercially beneficial process.

Recovery Apparatus

[00059] The method of the present invention as described above can be carried out on separate devices, or it can be carried out on a single apparatus.

[00060] Accordingly, in one embodiment of the present invention, there is provided an apparatus for obtaining a cobalt-enriched material from a discharged lithium ion cell comprising cobalt, the apparatus comprising: a crushing device; a sieving device and a magnetic device; wherein the sieving device is adapted to obtain particles of less than 4 mm in size, the magnetic device is adapted to generate a magnetic field of between 2000 and 8000 Gauss, and the apparatus does not include a heating device.

[00061] The crushing device may be any suitable device for crushing a spent lithium ion cell or battery. It may include rollers, shredders, impact crushers, hammer mills and the like.

[00062] The sieving device may comprise one or more sieves. The sieve(s) generally comprise a mesh with defined and uniform apertures that can be used to sort fragments into differently sized fractions. The sieve(s) can be selected by the skilled person depending on the particle fraction that is desired. Where more than one sieve is utilised, they can be used in series, that is, a fraction obtained from a first sieve (either the retained fraction or the fraction that passed through the sieve) can then be treated with a sieve with a different aperture, in order to obtain particles of a desired size range.

[00063] The magnetic device may be any suitable device for generating the required magnetic field (that is, between about 2000 and 8000 Gauss) and separating magnetic particles from non magnetic particles. The device may comprise a strong permanent magnet (such as, for example, a neodymium-based rare earth magnet) or an electromagnet. The magnetic device may also comprise a barrier between the particles and the magnet (to avoid the magnetic particles from adhering directly to the magnet), especially if a permanent magnet is being used. The barrier may be in the form of a rotating drum or a plate, for example.

[00064] The apparatus advantageously does not include a heating device. By "not include a heating device", it is meant that the apparatus does not include a device that has the sole, or main, purpose of raising the temperature of a material. In other words, whilst some elements of the apparatus may result in a temperature gain by a part of the battery or cell being processed (for example, the battery or cell fragments immediately after crushing are likely to have a higher temperature than the whole cell or battery before crushing), an increase in temperature is not the sole purpose or main aim of these elements. Put differently, the apparatus does not include a device for the sole purpose of heating any portion of the cell or battery being processed. This is an important aspect, as the ability to obtain a cobalt-rich product without a heating step provides the present invention with commercial advantages over other recycling or recovery processes, leading to an apparatus with low relatively energy costs and hence low operating costs.

[00065] The present invention will be further described below with reference to non-limiting worked examples.

Examples

[00066] A non-limiting example of the present invention is described below.

[00067] A spent lithium ion battery with NMC chemistry was obtained and discharged by immersion in a conductive electrolyte solution. The discharged battery was then crushed in an industrial shredding device and the solid fragment collected, with the liquid electrolyte discarded.

[00068] Large components are removed by hand, leaving behind the black mass powder, before sieves with different mesh sizes were then used to classify the black mass particles. To determine the best particle sizes, three different sieves were used, and the cobalt content of the resulting retained fraction analysed (as shown in Table 2 below and Figure 1). The mesh sizes used were 10 mesh (2000 microns), 16 mesh (1190 microns) and 230 mesh (63 microns).

Table 2: Cobalt content of black mass corresponding to different sieves.

Co content(%)

Original black mass 13

Sieve 1 (10 mesh) 18.6

Sieve 2 (16 mesh) 21.38

Sieve 3 (230 mesh) 23.77

[00069] As can be seen from Table 2 and Figure 1, the particles that are obtained from the sieving step include an enrichment of cobalt.

[00070] This enrichment is further increased by exposing these particles to a magnetic field. In particular, a rotating drum separator with a 30 cm diameter was used at a range of magnetic field strengths. As shown in Table 3 below, at relatively low magnetic fields (1000 Gauss), only 3% of the black powder was retained by the drum, increasing to 85% at 5000 Gauss. These results are shown in Figure 2.

Table 3: The black mass separation rate corresponding to the Gaussian intensity of magnetic separation.

Gaussian intensity Separation rate(%)

1000 G 3

2000 G 10

3000 G 45

5000 G 85

[00071] Accordingly, as can be seen, at relatively high magnetic fields, a greater proportion of material is separated from the black mass particles. Without being bound to theory, it is expected that the material retained on the drum is ferromagnetic and paramagnetic material, whereby the higher the magnetic field, the greater the amount of paramagnetic material is retained. Therefore, the combination of sieving followed by magnetic separation results in the collection of a product that is enriched in cobalt.

[00072] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms in particular features of any one of the various described examples may be provided in any combination in any of the other described examples. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.

Claims (13)

1. A method for obtaining a cobalt-enriched material, comprising: (a) providing a discharged lithium ion cell comprising cobalt; (b) crushing the cell to form fragments; (c) separating the fragments to obtain particles of less than 4 mm in size; and (d) treating the obtained particles with a magnetic field of between 2000 and 8000 Gauss, so as to select cobalt-enriched material from non-cobalt-enriched material, wherein the method does not comprise a heat treatment.

2. The method of claim 1, wherein the cell is a battery.

3. The method of claim 1 or claim 2, wherein the particles are between 63 m to 1.2 mm in size.

4. The method of any one of claims 1 to 3, wherein the separating includes sieving.

5. The method of any one of claims 1 to 4, wherein the magnetic field is between about 3000 and about 5000 Gauss.

6. The method of any one of claims I to 5, wherein the magnetic field is provided by a magnetic separator and/or an eddy current device.

7. The method of claim 6, wherein the magnetic separator is a rotating shaft drum.

8. The method of claim 7, wherein the rotating shaft drum has a diameter of less than about 30 cm.

9. The method of any one of claims 1 to 8, wherein step (d) further comprises treating the particles with an electrostatic separation device.

10. The method of any one of claims I to 9, wherein step (b) further comprises the step of treating the fragments with a solvent.

11. The method of claim 10, wherein the solvent is N-methyl-2-pyrrolidone (NMP).

12. A product obtained from the method of any one of claims I to 11.

13. An apparatus for obtaining a cobalt-enriched material from a discharged lithium ion cell comprising cobalt, the apparatus comprising: a crushing device; a sieving device and a magnetic device; wherein the sieving device is adapted to obtain particles of less than 4 mm in size, the magnetic device is adapted to generate a magnetic field of between 2000 and 8000 Gauss, and the apparatus does not include a heating device.

Vincent Huang Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON