Patent Application
20240204277
The present invention relates to a method for extracting metals from lithium-ion battery material, particularly from the black mass obtained from said battery material. Such a black mass contains mainly cathode metals and anode material, and the cathode metals, in turn, typically comprise lithium and nickel, further possible cathode metals being cobalt, manganese and aluminium. The invention also relates to an arrangement that is suitable for use in the method.
The use of lithium-ion batteries has grown steadily for the last years, and their importance appears to grow even further as the development of new electric vehicles continues. Lithium ion batteries contain, in their cathodes, several transition metals that can be valuable when recovered from these batteries, either for reuse in new batteries or for other purposes. Particularly the lithium of these materials should be recovered and reused.
Hydrometallurgical separations of metals from lithium-ion batteries proceed via the recovery of a black mass, which contains cathode metals and anode material, but from which wiring and other coarse solid battery components, such as plastic or steel parts, have already been removed.
The next step in the recovery of the metals, after the formation of the black mass, is typically the separation of the cathode metals from the other components of the black mass, e.g. using mechanical, thermal or chemical pre-treatment steps, followed by acid leaching to solubilize the cathode metals, and prepare them for recovery.
Each step of the overall hydrometallurgical process poses a risk for metal losses, which losses should naturally be reduced. The present inventors have now found a new procedure for reducing lithium losses.
The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.
According to a first aspect of the present invention, there is provided a method for extracting metals from the black mass obtained from lithium-ion battery material, the black mass containing the anode and cathode materials of the batteries. Particularly, the metals that are extracted include lithium and nickel, and possibly other transition metals, such as cobalt, manganese and aluminium.
According to a second aspect of the invention, there is provided a method aiming at increasing the recovery of lithium.
According to a third aspect of the invention, there is provided a method including one or more steps for recycling lithium-containing fraction(s) to the leaching step, to provide an increased lithium recovery.
According to a further aspect of the invention, there is provided an arrangement suitable for use in carrying out the steps of the method of the invention.
The method of the invention thus comprises
Likewise, the arrangement of the invention comprises
Thus, the invention is related to the recovery of fractions containing minor amounts of lithium, to be combined with the main lithium fraction, thus increasing the yield or recovery of lithium product in the metal separation steps.
The present invention thus provides several advantages. Naturally, an increased lithium yield is achieved. However, the recycling options of the invention also reduce the amount of lithium in the waste effluents, thereby simplifying the waste treatment requirements. Lithium can cause problems in waste treatments, and the present method is capable of decreasing the amount of lithium in the waste effluents to a significant degree.
The present invention relates to a method for extracting metals from the black mass of lithium-ion battery material. The method comprises the following steps:
The black mass of lithium ion batteries typically contains both cathode and anode materials, as well as electrolyte materials with organic compounds. For the purposes of the invention, the organic compounds are preferably removed from the black mass by the above mentioned pre-treatment step(s). For example, one or more washing steps can be used, preferably carried out by mixing the battery material with water or an organic solvent, most suitably with water, whereby material that is dissolved or dispersed in said solvent, such as said organic compounds, can be separated from the undissolved components of the black mass. Alternatively, one or more heating steps, typically carried out as pyrolysis or evaporation steps, can be used to remove organic compounds, preferably carried out at a temperature of 195-470° C. A further option is to carry out both a washing step and one of the mentioned heating procedures.
The pre-treatment step(s) thus yield a pre-treated black mass that preferably contains the lithium, nickel and cobalt, and possibly manganese, of the battery cathode, in oxide form, and more preferably contains only <3% by weight of remaining organic compounds, most suitably <1.5% by weight.
In a preferred embodiment of the invention, at least a fraction of the lithium typically lost in the optional washing steps is recovered by
After the pre-treatment step(s), a solid/liquid separation is typically carried out, whereby the pre-treated black mass can be carried to the following leaching step, and optionally mixed with added metal-containing solids or slurry, such as a lithium phosphate precipitate recycled from either the pre-treatment steps or the metal recovery steps.
In an embodiment of the invention, only one leaching step is used, which is said acid leaching step, carried out in a solution containing sulphuric acid. Typically, the acid leaching is thus carried out by dispersing the pre-treated black mass into a solution containing the acid, and adding the optional extractants, preferably followed by mixing.
The temperature during the leaching step is preferably adjustable, whereby the temperature most suitably is maintained at an elevated level during the acid leaching, such as a temperature of >50° C., preferably a temperature of 50-95° C., and more preferably a temperature of 60-90° C. Similarly, the pressure during the acid leaching is preferably maintained at atmospheric pressure, or slightly elevated pressure of 100-200 kPa. Typically, the solubilisation of the desired transition metals is complete within a time of 2-6 hours.
The sulphuric acid addition is used in part to adjust the pH of the leaching solution. The pH of the leaching solution is thus preferably adjusted to a level of 0-5, more preferably 1-2, using said sulphuric acid, before adding the optional extractants, preferably selected from hydrogen peroxide, a carbohydrate and sulphur dioxide, due to their reductive capabilities, providing a more effective dissolution.
After the leaching reaction is complete, i.e. after the pre-treated black mass has spent a sufficient amount of time, such as 2-6 hours, in the leaching conditions, a solid/liquid separation is typically carried out, in order to recover the leach solution containing the cathode metals, whereby it can be carried to the following step of the method, for recovery of separate metallic fractions.
In an embodiment of the invention, the recovery of main fractions of metallic material including at least nickel and lithium ions is preferably preceded by the one or more steps for separating initial fractions of metallic material from the leach solution. Said initial fractions of metallic material (or “the initial metallic fractions”) typically include at least one of iron, aluminium, calcium and fluoride ions, and possible phosphates. This order of steps has the advantage of providing a purified solution for the recovery of the main fractions of metallic material, since the initial fractions include the materials that are considered to belong to the impurities. These materials would also impair the subsequent recoveries of the main fractions, or at least result in lower purity or lower yields, if left in the leach solution.
Preferably, the step(s) for separating initial fractions of metallic material from the leach solution include the steps for separating two or more of, preferably three or four of, and most suitably all of, iron, aluminium, calcium and fluoride ions. Also copper can be included in these initial fractions. Optionally, a separate copper recovery step can be carried out, preferably before the other initial fraction(s) are separated from the solution.
Typically, the separation(s) of initial fractions of metallic material include at least one step carried out as a solvent extraction (SX), intended to remove said impurities, such as iron and aluminium, from the leach solution, optionally preceded by a solid separation, to remove any impurities already in solid form, thus increasing the selectivity of the solvent extraction
In another alternative, the separation(s) of initial fractions of metallic material include at least one step carried out as a precipitation, for example a hydroxide precipitation, intended to remove impurities, such as iron and aluminium, as a solid fraction from the leach solution. Such a hydroxide precipitation has been shown to be effective also for precipitating phosphates, such as the phosphate of the recycled lithium phosphate obtained from the lithium recovery steps and optionally from the pre-treatment steps.
In a particularly preferred alternative, the separation of initial fractions of metallic material includes a precipitation, with an optional separation of the precipitated impurities, that is followed by a solvent extraction, both steps as described above. The advantage of such a two-step impurity separation is that the contents of impurities, such as iron and aluminium, are further decreased in the thus purified leach solution. It is particularly preferred to carry out the precipitation before the solvent extraction in such a two-step separation of initial metallic fractions, since this will facilitate a high selectivity in the solvent extraction.
In case the copper is separately recovered, this copper recovery step is preferably carried out before said initial fractions of metallic material are separated from the leach solution, since copper can have a negative impact on subsequent recoveries and more importantly product qualities.
Since the acid leaching step has been carried out in an acid solution, the first metal separation step is required to endure acidic conditions. This requirement is fulfilled for the separations of the initial metallic fractions.
Various reactions and procedures can be utilized to carry out said metal separations and recoveries, such as further leaching or washing steps, solvent extractions, precipitations, ion exchange steps, and electrowinning steps. However, for the separations of the initial metallic fractions it is preferred to utilize at least one solvent extraction, since this will result in a higher purity of the remaining solution, thus also facilitating the subsequent recoveries of the main fractions, particularly the recovery of cobalt and nickel, whereby all of the metals of the main fractions can be recovered in high yield and high purity, typically as battery-grade materials.
As mentioned above, the recoveries of the main fractions of metals include steps for recovering at least nickel and lithium ions, and possibly cobalt and manganese, although the recoveries can be carried out in varying order.
Particularly, the recoveries of the main fractions include steps for recovering at least one of, preferably both of manganese and cobalt, in addition to said nickel and lithium ions. Typically, any manganese, cobalt and nickel are recovered before said lithium.
A lithium recovery is thus preferably carried out after the separation of the initial metallic fractions, and more preferably also after any of the manganese, cobalt, and nickel present in the leach solution have been recovered. Using this preferred order of steps will result in a situation, where the lithium can be recovered from a high-purity lithium-containing solution.
The lithium is recovered by reacting the lithium into its carbonate, producing a product fraction that can be recovered as such, or alternatively be further converted into e.g. lithium hydroxide, which can then be crystallized into pure hydroxide crystals.
A further option for the lithium recovery is to use a solvent extraction, after which a further conversion or crystallization can be carried out. The benefit of this procedure is an even higher lithium recovery.
The liquid fraction obtained when reacting the lithium into its carbonate still contains some lithium that may be recovered separately. This liquid fraction is thus reacted further with a phosphate reagent, and possibly a separate precipitation reagent, thus causing precipitation of the lithium remaining therein into a lithium phosphate precipitate, at least a fraction of which, after a separation of the precipitate from the remaining effluent, can be recycled to the leaching step by mixing it with the pre-treated black mass. Also, a fraction of the precipitated lithium phosphate may be directed to the above described steps for lithium recovery, where the phosphate, together with the carbonate, can be reacted into lithium hydroxide.
The phosphate reagent used above can be selected from any phosphates of alkali or earth alkali metals. However, sodium phosphate (Na3PO4) is preferred, since it brings no new cations to the reaction mixture, and since it has a suitable reactivity.
The precipitation of the lithium in the lithium-containing liquid fraction, e.g. obtained when reacting the lithium into its carbonate, into lithium phosphate is typically carried out at a temperature of 50-90° C., preferably 70-90° C. The pH, in turn, is typically maintained at 4 or higher, preferably at 7 or higher.
The same conditions and reagents as used here for the liquid fraction obtained when reacting the lithium into its carbonate can be used also for the washing solution obtained from the pre-treatment steps, optionally treated for lithium recovery by precipitation into lithium phosphate.
A nickel recovery is also carried out on the leach solution, preferably after the separation of the initial metallic fractions, typically taking place either simultaneously with or directly after the optional recovery of cobalt, more preferably after the cobalt is recovered, and most suitably before the above mentioned lithium recovery. Similarly, it is preferred to carry out the nickel recovery after an optional manganese recovery.
Said nickel recovery can be carried out, for example using a solvent extraction (SX), which produces a rather pure nickel sulphate solution (NiSO4). This solution is optionally purified further, e.g. by ion exchange (IX), after which a crystallization can be carried out, or a precipitation into a hydroxide or a carbonate, or the sulphate solution can be used as such, without crystallization or precipitation, e.g. in the preparation of new cathode materials. The optional solvent extraction for nickel recovery is most suitably carried out using extraction chemicals having a carboxylic acid functional group, one commercial example of suitable extraction chemicals being Versatic™ 10, which is a neodecanoic acid.
A cobalt recovery is also preferably carried out on the leach solution after the separation of the initial metallic fractions, typically taking place either simultaneously with or directly before the recovery of nickel, more preferably before the nickel is recovered, and most suitably also before the lithium is recovered. Similarly, it is preferred to carry out the cobalt recovery after an optional manganese recovery.
A preferred option for said cobalt recovery is a solvent extraction (SX), which produces a rather pure cobalt sulphate solution (CoSO4). This solution is optionally purified further, e.g. by ion exchange (IX), after which a crystallization can be carried out, or a precipitation into a hydroxide or a carbonate, or the sulphate solution can be used as such, without crystallization or precipitation, e.g. in the preparation of new cathode materials. The optional solvent extraction for cobalt recovery is most suitably carried out using extraction chemicals having a carboxylic acid functional group, such as the phosphinic acid functional group, one example of suitable extraction chemicals being Cyanex™ 272, which is also known as trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate.
In one alternative manner of proceeding with the metal separation steps, as indicated above, cobalt and nickel can be recovered simultaneously from the leach solution, for example by a solvent extraction, thus producing a sulphate solution, optionally followed by a further purification by ion exchange (IX), or a precipitation into the hydroxides or the carbonates. Alternatively, the sulphate solution can be used as such, without crystallization or precipitation, e.g. in the preparation of new cathode materials.
According to an embodiment of the invention, the metal separation steps include a step for recovering manganese from the leach solution, the manganese recovery also carried out after the separation of the initial metallic fractions. Preferably, the manganese is recovered before the recovery of nickel or the optional recovery of cobalt, and most suitably before any of the nickel, cobalt or lithium are recovered.
Options for said manganese recovery include solvent extractions, precipitations and crystallizations, or a solvent extraction followed by a precipitation or crystallization. One particularly preferred option is to utilize an oxidative precipitation using sulphur dioxide, SO2, and air, to form the manganese oxide, MnO2.
The method of the invention can be carried out in any suitable apparatus or arrangement, with the units and equipment needed to carry out the steps of the method.
In one embodiment of the invention, the method described above is carried out using the arrangement of
In an embodiment of the invention, with various options illustrated in
In a preferred embodiment of the invention, as illustrated in
The leaching unit(s) 2 typically consist of only said acid leaching unit(s) 21, which in turn is preferably equipped with the required inlets 211 for sulphuric acid and extractants, as well as means 212 for adjusting the temperature, which can incorporate either heating or cooling, as shown in
The metal separation units 3 preferably include several subunits, all subunits typically equipped with the further subunits e.g. solvent extraction units, ion exchange units, precipitation units, electrowinning units, washing units or solid/liquid separation units), recycle lines, inlets and outlets needed to carry out the reactions they are intended for.
Preferably, the metal separation unit 3 includes, in addition to the unit 35 for recovering nickel and the unit 36 for recovering lithium, one or more further units 33,34 for recovering manganese and cobalt ions, as illustrated in
In case copper is separately recovered in the arrangement, the copper recovery unit 31 is preferably placed upstream from the other unit(s) 32 for separating initial metallic fractions from the leach solution.
Various types of units and equipment can be utilized to carry out said separations and recoveries, such as further leaching or washing units, solvent extraction units, precipitation units, ion exchange units, and electrowinning units. However, solvent extraction units are preferred. Particularly, it is preferred to utilize at least one solvent extraction unit for the separations of the initial metallic fractions. More preferably, the solvent extraction is preceded by a solid separation unit, which, in turn, optionally is preceded by a precipitation unit for such impurities.
The units 33,34,35,36 for recovering the main fractions of metallic material thus include units for recovering at least nickel and lithium ions, and can typically be placed in any suitable order, with nickel recovered before lithium.
In a preferred embodiment of the invention, any unit(s) 34,35 for recovering cobalt and nickel are positioned upstream from the unit 36 for recovering lithium.
In another preferred embodiment of the invention, a unit 33 for recovering manganese is included in the arrangement, and is positioned upstream from any units 34,35,36 for recovering cobalt, nickel and lithium.
In one alternative manner of selecting and positioning the metal separation units 3, the cobalt and the nickel can be recovered in the same unit 34/35.
As mentioned above, the lithium recovery unit 36 includes subunits, such as
Further, as shown in
It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.
As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. In addition, various embodiments and examples of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention.
The following non-limiting example is intended merely to illustrate the advantages obtained with the embodiments of the present invention.
30.5 g of a lithium phosphate, Li3PO4, containing solid sample with the composition of 15.4% Li and 22.1% of P was leached at a temperature of 80° C. in an agitated reactor. The lithium phosphate was pulped in 0.9 L of 80 g/L sulfuric acid solution and agitated for 2 h.
The leach solution was analysed and contained 5140 mg/L Li and 7540 mg/L P at pH 1.1. The calculated leaching yield for lithium was 98.5%, as shown in the following Table 1.
In the following step, the lithium phosphate was precipitated. 1.4 L of the above black mass leach solution at 40° C. was placed to an agitated reactor, followed by step wise addition of 500 g/L NaOH containing solution to increase the pH from 3 to 5 and remove phosphate, iron and aluminium. Efficient removal of phosphate was observed, as shown by the decreased phosphate contents of the solution in the following Table 2.
The present method, and the arrangement suitable for use in said method, can be used to replace conventional alternatives for recovery of metals from the black mass obtained from lithium-ion batteries.
In particular, the present method and arrangement provides an economical and efficient procedure for recovering at least nickel and lithium, as well as optionally cobalt and manganese, in good yields from such battery material. The yield of lithium is further increased by recovering and recycling the lithium obtained from one or more waste effluents of the method.
As shown in the
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FI2021/050270 | 4/14/2021 | WO |
