Related Application

This application claims priority from Great Britain Patent Application No. GB2207576.6 filed on 24 May 2022, the entire contents of which is incorporated herein by reference.

Field

The present specification relates to a method of recycling battery waste material comprising Li and one or more of Mn, Co, and Ni. For example, certain lithium-ion battery cathode materials comprise all of Ni, Co, Mn, and Li. In this case, the present specification can be used to separate and purify all four of these elements from spent or scrap lithium-ion battery cathode material for re-use, for example, in manufacturing new lithium-ion battery cathode materials.

Background

Lithium-ion batteries are now ubiquitous in modern society, finding use not only in small, portable devices such as mobile phones and laptop computers but also increasingly in electric vehicles.

A lithium-ion battery generally includes a graphite anode separated from a cathode by an electrolyte, through which lithium ions flow during charging and discharging cycles. The cathode in a lithium-ion battery may include a lithium transition metal oxide, for example a lithium nickel oxide, lithium cobalt oxide or lithium manganese oxide.

Although lithium-ion and other modern rechargeable batteries offer a promising low-carbon energy source for the future, one concern is that the metals required for their manufacture, such as lithium, nickel, cobalt and/or manganese, often command high prices due to their limited availability and difficulty of extraction from natural sources. There is therefore a need for methods which recycle or purify the metals present within batteries, such as the metals present within the cathodes of batteries, to provide materials which may be used as feedstock in battery manufacture.

Both pyrometallurgical and hydrometallurgical processes for recycling of battery waste materials are known. Pyrometallurgical processes utilize a range of high temperature techniques including one or more of thermal reduction, roasting, pyrolysis, melting, and vaporization. In contrast, hydrometallurgical processes are lower temperature solution-based processes which utilize a range of techniques including one or more of dissolution, leaching, solvent extraction, solid phase extraction, electrochemical extraction, and precipitation processes. Both approaches have advantages and disadvantages. Pyrometallurgical processes can be less complex, using well established thermal processing techniques. However, they tend to have high energy consumption, hazardous gaseous emissions, and significant material losses, e.g., Li in slag. In contrast, hydrometallurgical processes can require a more complex sequence of solution processing techniques, but have a lower energy consumption, no hazardous gaseous emissions, and can have high recovery efficiencies or a wider range of metals with high quality/purity output streams/materials for reuse in manufacturing new battery materials.

In light of the aforementioned environmental and performance benefits of hydrometallurgical processes, it is considered that this is the preferred approach for battery materials recycling.

During hydrometallurgical battery material recycling processes, an effluent solution is generated containing valuable metal elements which could be used in the manufacture of new battery materials if they could be extracted in sufficient purity. Such solutions may be generated by leaching from waste battery materials including so-called “black mass”, a mixture of valuable metals alongside unwanted impurities. Such solutions therefore include other less desirable or unwanted metal elements or impurities. The solutions may thus contain a complex mixture of metal elements and it is often desirable to extract only one, or a limited number, of these metal elements in any single processing step.

It is often necessary to perform multiple separate extraction steps, using different solvent extractants or solid phase extractants, in order to selectively extract a range of metals from battery waste solutions. Typical prior methods involve leach of Mn, Co, Ni, and Li from a battery waste material in a strong acid (e.g., sulfuric acid) to form an acidic aqueous recycling feed (e.g., pH 0-1). The pH of the acidic aqueous recycling feed is then sequentially increased to an appropriate pH for each subsequent extraction step. Typically, this will follow a sequence: pH 3 for extraction of Mn using, for example, D2EPHA (di-2-ethylhexyl phosphoric acid); pH 5 for extraction of Co using, for example, Cyanex™ 272 (a dialkyl phosphinic acid extractant); pH 6-7 for extraction of Ni; and pH 7-10 for extraction/recovery of Li (e.g., via precipitation). However, using this approach all the sulfuric acid in the acidic aqueous recycling feed is converted to sodium sulphate waste by-product which is not an environmentally friendly, efficient, sustainable, and cost-effective feature of the overall process.

Variants of the aforementioned process are known in which Li is removed first prior to acid leaching to form the acidic aqueous recycling feed. However, such alternative processes still require a sequential increase in pH of the acidic aqueous recycling feed for the various extraction steps for Mn, Co and Ni up to a final pH around 6-7. As such, even with these variants a substantial portion of the sulfuric acid in the acidic aqueous recycling feed is converted to sodium sulphate waste by-product.

As such, there is still need for a more environmentally friendly, efficient, sustainable, and cost- effective process for the hydrometallurgical recycling of battery waste materials.

Summary of the Invention

According to the present specification there is provided a method of recycling a battery waste material comprising Li and one, more or all of Mn, Co, and Ni.

The method comprises extracting Li from the battery waste material by selectively dissolving Li in a solvent. The solvent in which the Li is extracted can be an organic acid, optionally formic acid, in which Li is soluble while Ni, Co, and Mn are insoluble. Alternatively, the Li- species in the battery waste material can be reduced using a reductive thermal treatment prior to selectively dissolving the Li in the solvent, optionally an aqueous based solvent, e.g., water.

After extracting Li, an acidic aqueous recycling feed of the battery waste material is formed by leaching the battery waste material with an acid (e.g., comprising or consisting of sulphuric acid). At this stage, the acidic aqueous recycling feed comprises one, more, or all of Mn, Co, and Ni in solution at a pH < 2, optionally < 1 .5, optionally < 1 .0. The pH of the acidic aqueous recycling feed may be > 0, e.g., within a range 0 to 2, 0 to 1.5, or 0 to 1.0.

The acidic aqueous recycling feed is then subjected to a sequence of extraction steps to extract one, more, or all of Mn, Co, and Ni from the acidic aqueous recycling feed. A key feature of the present method is that the pH of the acidic aqueous recycling feed is maintained at a pH < 4 for all extraction steps. Optionally, the acidic aqueous recycling feed is maintained at a pH < 3.5 or < 3 during all extraction steps for Mn, Co, and/or Ni. Furthermore, optionally the acidic aqueous recycling feed is maintained at a pH > 2 during all extraction steps for Mn, Co, and/or Ni, e.g., within a pH range 2 to 4, 2 to 3.5, or 2 to 3. By keeping the pH low, formation of Na2SO4 (or an equivalent salt) is reduced and a significant portion of free acid can be regenerated and re-used. That is, after extracting one, more or all of Mn, Co, and Ni from the acidic aqueous recycling feed, the acid from the acidic aqueous recycling feed can be recycled for re-use in further leaching of battery waste material. A process to concentrate the acid (e.g., a distillation process) may be utilized as part of the circuit for recycling of the acid from the acidic aqueous recycling feed for re-use in further leaching of battery waste material.

In accordance with the present specification, the pH of the acidic aqueous recycling feed is kept low throughout the process thus enabling acid to be recycled and re-used. Such a process generates less waste material and is more environmentally friendly, efficient, sustainable, and cost-effective.

Various extraction methods can be utilized to extract one or more of Mn, Co, and Ni from the acidic aqueous recycling feed. For example, the steps of extracting one, more, or all Mn, Co, and Ni from the acidic aqueous recycling feed may comprise contacting the acidic aqueous recycling feed with one or more organic solvent extraction compositions, stripping one or more of Mn, Co, and Ni from the one or more organic solvent extraction compositions, and recycling the one or more organic solvent extraction compositions for re-use in extracting further Mn, Co and/or Ni from the acidic aqueous recycling feed. In accordance with certain examples both Ni and Co are extracted into the same organic solvent extraction composition, and the method further comprises selectively stripping the Ni and Co from the organic solvent extraction composition to produce two separate aqueous solutions, one comprising Ni and one comprising Co. The Mn can be extracted into a different organic solvent extraction composition than the Ni and Co. As such, the process for extracting Mn, Ni, and Co can be done in two separate solvent extraction processes, one for Mn and one for Ni and Co.

If organic solvent extraction compositions are utilized for the extractions, the organic solvent extraction compositions can be recycled for re-use in extracting further Mn, Co, and/or Ni from the acidic aqueous recycling feed. This may comprise treating the one or more organic solvent extraction compositions with a base to regenerate the one or more organic solvent extraction compositions for re-use in extracting further Mn, Co and/or Ni from the acidic aqueous recycling feed. In accordance with certain examples, one, more, or all of Mn, Ni, and Co are stripped from the one or more organic solvent extraction compositions using an acid and then the one or more organic solvent extraction compositions are treated with a base to regenerate the one or more organic solvent extraction compositions for re-use.

As an alternative, one or more of the extraction steps can be performed using a solid phase extractant medium rather than a solvent extraction medium. In this case, it is also advantageous to regenerate the solid phase extraction media for re-use in extracting further Mn, Co and/or Ni from the acidic aqueous recycling feed. This can be done by stripping the extracted Mn, Co and/or Ni from the solid phase extraction media using a stripping reagent. Following the aforementioned methodologies both the acid and the extraction media can be recycled and re-used further improving the overall process in terms of generating less waste material and being more environmentally friendly, efficient, sustainable, and cost-effective.

In addition to Mn, Co and Ni, the acidic aqueous recycling feed may comprise impurity elements including one or more of Al, Cu and Fe. In this case, after forming the acidic aqueous recycling feed and prior to extracting one or more of Mn, Co, and Ni from the acidic aqueous recycling feed, the acidic aqueous recycling feed can be subjected to one or more treatment steps to extract these impurity elements. In accordance with the present methodology, the acidic aqueous recycling feed is maintained at a pH < 4, optionally < 3.5, optionally < 3.0, optionally > 2, during these impurity removal treatment steps. Again, the pH of the acidic aqueous recycling feed must be kept low throughout the process to enable efficient recycling of acid, thus generating less waste material. Furthermore, as with the Mn/Co/Ni extractions, the extraction media used to extract the impurity elements can also be regenerated and reused to extract further impurity elements from the acidic aqueous recycling feed. The extraction media used to extract impurity elements may comprise one or more solid phase extraction media. In certain preferred examples, one or more impurities are extracted using one or more solid phase extraction media and the Mn/Co/Ni are extracted using organic solvent extraction compositions.

Brief Description of the drawings

For a better understanding of the present invention and to show how the same may be carried into effect, certain embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

Figure 1 shows a battery materials recycling process not according to the present specification;

Figure 2 shows another battery materials recycling process not according to the present specification;

Figure 3 shows another battery materials recycling process not according to the present specification;

Figure 4 shows a battery materials recycling process according to the present specification;

Figure 5 shows another battery materials recycling process according to the present specification; and

Figure 6 shows another battery materials recycling process according to the present specification. Detailed Description

As described in the summary section, the present specification provides a method of recycling battery waste material comprising Li and one or more of Mn, Co, and Ni which generates less waste material and is more environmentally friendly, efficient, sustainable, and cost-effective when compared to prior art methods.

Figure 1 shows a typical prior art battery materials recycling process. Battery waste material such as black mass or cathode scrap is subjected to a strong acid leach in order to form an acidic aqueous recycling feed (pH 0-1) comprising Mn, Co, Ni, and Li. The acidic aqueous recycling feed may also comprise impurities Al, Cu, and Fe. These impurities can be extracted using solvent or solid phase extractants prior to extracting the Mn, Co, Ni, and Li. Alternatively, the impurities can be removed by hydrolysis with, for example, NaOH or Ca(OH)2 which needs to be competed at a pH of up to 6/7 to achieve full removal. The solution is then re-acidified to selectively extract the value metals by solvent extraction. The pH of the acidic aqueous recycling feed is sequentially increased to an appropriate pH for each extraction step. Typically, this will follow a sequence: pH 3 for extraction of Mn using, for example, D2EPHA; pH 5 for extraction of Co using, for example, Cyanex™ 272; pH 6-7 for extraction of Ni; and pH 7-10 for extraction/recovery of Li (e.g., by precipitation as a carbonate salt or via solvent extraction using Cyanex™ 936 which is a phosphorus-based extractant specifically formulated for lithium). However, using this approach all the sulfuric acid in the acidic aqueous recycling feed is converted to sodium sulphate waste by-product which is not an environmentally friendly, efficient, sustainable, and cost-effective feature of the overall process.

Figure 2 shows another battery materials recycling process which is similar to Figure 1 in that it comprises: an acid dissolve to form an acidic aqueous recycling feed (pH 0-1) comprising Mn, Co, Ni, and Li; removal of impurities; and then a sequence of extractions for Li, Mn, Co, and Ni. In the process illustrated in Figure 2, the Co and Ni are extracted in a single solvent extraction. An acid scrub can further be applied to the organic phase to remove any remaining impurities prior to selectively stripping of the Co and Ni into aqueous Co and Ni solutions. The organic phase can be regenerated and recycled for use in further extraction of Co and Ni. The method of Figure 2 enables Co and Ni to be separated from the cathode black mass material. Further process steps are required for extracting Mn and Li. Typically, this will involve increasing the pH of the acidic aqueous recycling feed as in the process of Figure 1 leading to sodium sulphate waste by-product. Figure 3 shows yet another battery materials recycling process. This process differs from that illustrated in Figures 1 and 2 in that the Li is extracted from the battery waste material prior to the acid dissolve to generate the acidic aqueous recycling feed. By removing the Li up front in the process, the pH is not required to be increased quite so much at the end of the process as in the method of Figure 1 or 2 where Li is extracted last. Once the acidic aqueous recycling feed is formed comprising Mn, Co, and Ni, impurities can be removed and then the Mn, Co, and Ni extracted in sequence. The Mn is typically extracted at pH 3, the Co is typically extracted at pH 5, and the Ni is typically extracted at pH 6 - 7. While the final pH is lower than in the method of Figure 1, a significant quantity of sodium sulphate waste by-product is still generated.

In contrast, Figure 4 shows a battery materials recycling process according to the present specification. A key difference between the method of Figure 4 and that of the preceding Figures is that the pH of the acidic aqueous recycling feed is maintained at < 4 throughout the process. This ensures that there is a significant proportion of free acid which can be recycled at the end of the extraction steps. As in the method of Figure 3, Li is extracted up front in the process prior to the strong acid leach to form the acidic aqueous recycling feed. Impurities can then be extracted using solvent or solid phase extraction techniques. In the method of Figure 4 it is important to perform the impurity removal steps while maintaining the pH of the acidic aqueous recycling feed at a pH < 4. The Mn, Co, and Ni can then be extracted. Again, it is important that the pH of the acidic aqueous recycling feed is maintained at a pH < 4 during all of these extraction steps. The process of Figure 4 comprises the sequence: Mn extraction; Co extraction; followed by Ni extraction. However, the order of the extraction steps can be varied. Furthermore, it is also possible for combinations of elements to be extracted together and then selectively stripped.

In the method of Figure 4, after extraction of each target element, the target element can be stripped from the extractant which can then be recycled for reuse. Furthermore, at the end of the sequence of extractions, because the pH of the acidic aqueous recycling feed has been kept low, there is a significant amount of free acid which can be recycled for re-use in the acid leaching step. The acid can be recovered and purified using distillation processes as is known in other manufacturing processes involving the use of strong acids. See, for example, Special Issue on Global Environment: Reduction of Waste in Semiconductor Manufacturing Plant (Sulfuric Acid Recycling Technology), Hiroshi OGATA and Norio TANAKA, which is incorporated herein by reference.

Figure 5 shows a variant of the processes shown in Figure 4. Again, Li is extracted first prior to forming the acidic aqueous recycling feed. Furthermore, as with the process shown in Figure 4, subsequent extractions steps for both the impurities and the target Mn, Co, and Ni species are performed while maintaining the acidic aqueous recycling feed at a pH < 4 such that there is a significant proportion of acid which can be recycled and reused with less sodium sulphate waste by-product than prior art processes. The difference in Figure 5 is that the Co and Ni are extracted in a single extraction step followed by selective stripping to separate the Co and Ni. Furthermore, while the process flow shows extract of Mn prior to extraction of Co/ Ni, it is also envisaged that the Co/Ni can be extracted from the acidic aqueous recycling feed prior to the Mn.

Figure 6 shows another battery materials recycling process which is similar to that shown in Figure 5. Again, Li is extracted first prior to forming the acidic aqueous recycling feed. Furthermore, as with the process shown in Figure 5, subsequent extractions steps for both the impurities and the target Mn, Co, and Ni species are performed while maintaining the acidic aqueous recycling feed at a pH < 4 such that there is a significant proportion of acid which can be recycled and reused with less sodium sulphate waste by-product than prior art processes. The process flow shown in Figure 6 also shows the combined Co/Ni extraction followed by an acid scrub to remove any remaining impurities followed by selective stripping of Co and Ni and regeneration of the organic extractant for re-use in the solvent extraction step.

Examples of methods and materials which may be used in each extraction step of the process flow are set out below. However, it should be noted that these are provided as examples only and the present invention is not intended to be limited to specific extractants and extraction processes as a number of alternatives exist for each individual step. The key feature of the present specification is that the pH of the acidic aqueous recycling feed is maintained at low pH throughout the process flow and that significant quantities of free acid are maintained, recycled and re-used in the acid dissolve step to form the acidic aqueous recycling feed.

Li extraction

Li can be selectively leached from the battery waste material using an organic acid such as formic acid. A suitable method is described in W02022/079409, which is incorporated herein by reference. The Li can then be recovered from the organic acid. One such method to recover the Li from the organic acid is an electrochemical method to convert the Li in the organic acid into LiOH in aqueous solution. A suitable method is described in GB2113426.7, which is incorporated herein by reference, which describes the use of an electrochemical cell comprising one or more membranes which are selective to the transmission of monovalent lithium over multivalent transition metals such that the electrochemical cell functions to both convert the lithium into lithium hydroxide and also separate the lithium from multivalent transition metal impurities in the leachate.

Alternatively, the Li can be selectively extracted from the battery waste material by thermally treating the battery waste material followed by selectively dissolving the Li in an aqueous solvent (e.g., water). Suitable methods are described in WO2019197192 and W02020011765, both of which are incorporated herein by reference.

Removal of Impurities

After extracting the Li from the battery waste material, the battery waste material is leached with a strong acid (e.g., sulfuric acid) to form an acidic aqueous recycling feed. In addition to Mn, Co, and Ni, the acidic aqueous recycling feed may comprise impurities including one or more of Cu, Al, and Fe. Such impurities can be extracted from the acidic aqueous recycling feed prior to further processing to extract Mn, Co, and Ni. A key feature is that extraction media should be selected such that they extract the impurities at a pH < 4, 3.5, or 3. Optionally the pH may be maintained in a range 2 to 4 for these impurity extraction process, e.g., 3.

Fe can be removed from the acidic aqueous recycling feed using a solid phase extractant material which comprises a solid substrate material coupled to functional groups which are selective for uptake of Fe. A suitable method is described in GB2113378.0, which is incorporated herein by reference. The method comprises: contacting the acidic aqueous recycling feed with a solid phase extractant material which selectively adsorbs the iron, the one or more valuable metal elements Co, Ni, Mn remaining in solution; and recovering the iron from the solid phase extractant material by contacting the solid phase extractant material with a stripping agent comprising a solution of organic chelating molecules which form a complex with the iron.

The solid phase extractant material may comprise aminophosphonic acid groups such as aminomethylphosphonic acid (AMPA) groups for adsorbing the iron onto the solid phase media. Alternatively, or additionally, the solid phase extractant material may comprise aminophosphinic groups. Alternatively, or additionally, the solid phase extractant material may comprise sulfonic and phosphonic groups. The solid base material may comprise silica or a polymer such as polystyrene or a poly-glycidyl methacrylate (poly-GMA).

The stripping agent comprises organic chelating molecules which form a complex with iron. The organic chelating molecules are preferably soluble in water forming an aqueous solution. The organic chelating molecules may comprise aminoacetic functional groups and/or carboxylic functional groups. The organic chelating molecules may comprise one or more of an EDTA, an oxalate, a phthalic acid, an ascorbic acid, a citric acid, or a derivative thereof. The organic chelating molecules may comprise -COO groups, -COH groups, and/or -NH groups to chelate iron species. For example, the organic chelating molecules may comprise both amino groups and acid groups, with both the amino and acid groups functioning to chelate iron species. This allows the solid phase extraction media to be regenerated for re-use in extracting further Fe.

As an alternative or in addition to the above, D2EHPA (optionally with tri-n-butyl phosphate (TBP) added) can be used to extract Fe and Al impurities at a pH of <2 without taking substantial amounts of Mn, Co or Ni. The extracted impurities can be stripped from the organic extractant by use of a strong acid such as 1-3 M H2SO4 or HCI. Alternatively, using D2EHPA at a pH of 3-4 additionally co-extracts Mn and Cu. The Mn and Cu can be stripped using mild concentrations of acid and then the Al and Fe stripped using the stronger acids as previously mentioned.

Alternatively still, Cyanex™ 272 (dialkylphosphinic acid) can be used to extract impurities at a pH < 3 while giving a cleaner separation over Mn (see, for example, page 159 of Solvent extraction in the hydrometallurgical processing and purification of metals: process design and selected applications (researchgate.net) - Kathryn C. Sole, which is incorporated herein by reference). In the same reference, a range of chelating solvent extraction reagents are disclosed that work at pH < 4, e.g. LIX 65 (pH 3.3) or LIX 84 (pH 2.5), for extraction of Cu and Fe(lll) over Ni and Co.

Cu can also be extracted using a multi-dentate amine ligand solid phase extraction media such as Dupont’s AmberSep™ M4195 chelating resin or the chelating resin Lewatit™ TP 207 (which has chelating iminodiacetate groups). Alternatively, Cu can be electrowon or precipitated as a sulphide using NaHS at pH 1 to form CuS.

Extraction of Mn

Mn can be extracted from the acidic aqueous recycling feed using either a solid phase extractant or a solvent extractant at a pH < 4, 3.5, or 3. Optionally the pH may be maintained in a range 2 to 4 for this extraction process, e.g., 3. An example of a suitable extractant is di-2-ethylhexyl phosphoric acid (D2EHPA). See, for example, Vieceli, et al., Optimization of Manganese Recovery from a Solution Based on Lithium-Ion Batteries by Solvent Extraction with D2EHPA, Metals 2021 , 11, 54. See also US20130192425 and WO2016108343, both of which are incorporated herein by reference, which gives a list of extractants for Mn including: di-2-ethylnucleosilphosphoric acid (D2EHPA); 2- ethylnuclear silyl 2-ethylnucleosilphosphonic acid (PC 88A); bis (2,4,4-trimethylpentyl) phosphinic acid (Cyanex™ 272); or neodecanoic acid (Verstatic™ 10).

Extraction of Ni and Co

Ni and Co can be extracted from the acidic aqueous recycling feed using either a solid phase extractant or a solvent extractant at a pH < 4, 3.5, or 3. Optionally the pH may be maintained in a range 2 to 4 for this extraction process, e.g., 3.

A suitable solvent extraction method is described in PCT/GB2022/050912, which is incorporated herein by reference. The method uses an organic solvent extraction composition which comprises: an organic solvent which is immiscible with the acidic aqueous recycling feed; a picolinic acid ester or picolinic acid amide (e.g., n-Octyl picolinamide) which is soluble in the organic solvent; and a phase transfer catalyst or synergist (e.g., di-(2-ethylhexyl) phosphoric acid (D2EHPA) or (2- ethylhexyl)phosphoric acid (MEHPA)). Preferably the method comprises co-extraction of both Ni and Co into the organic solvent extraction composition and then selectively stripping the Ni and Co using acids of different strength to produce an aqueous solution of Ni and an aqueous solution of Co.

Alternatively, a solid phase extraction method can be used to extract the Co and/or Ni. A suitable solid phase extraction method is described in PCT/GB2022/050913, which is incorporated herein by reference. The method uses a separation material comprising picolinic acid ester or picolinic acid amide functional groups immobilised on a solid support. The solid support is selected from a silica solid support, a silica-polymer composite solid support and/or an optionally cross-linked methacrylate solid support. The functional groups may be picolinamide functional group which are attached to the solid support via a covalent linker.

Acid Recovery

By keeping the pH low throughout the aforementioned extraction steps, formation of Na2SO4 (or an equivalent salt) is reduced and a significant portion of free acid can be regenerated and re-used. That is, after extracting one, more or all of Mn, Co, and Ni from the acidic aqueous recycling feed, the acid from the acidic aqueous recycling feed can be recycled for re-use in further leaching of battery waste material. A process to concentrate the acid (e.g., a distillation process) may be utilized as part of the circuit for recycling of the acid from the acidic aqueous recycling feed for re-use in further leaching of battery waste material. Processes to recover, purify, and concentrate acids such as sulfuric acid are known from other industrial applications such as semiconductor manufacturing. See, for example, De Dietrich Process Systems’ sulfuric acid treatment process (https://www.dedietrich.com/en/solutions-and- products/mineral-acid-treatment/sulfuric-acid-treatment) and Reduction of Waste in Semiconductor Manufacturing Plant (Sulfuric Acid Recycling Technology), Oki Technical Review 160, Vol. 63, January 1998 by Hiroshi OGATA and Norio TANAKA, both of which are incorporated herein by reference.

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.

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’.

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.

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”. 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).

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.

As used herein, with reference to numbers in a range of numerals, the terms “about”, “approximately” and “substantially” 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 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, from 8 to 10, and so forth.

Forms of the present invention includes:

1. A method of recycling a battery waste material comprising Li and one or more of Mn, Co, and Ni, the method comprising: extracting Li from the battery waste material by selectively dissolving Li in a solvent; after extracting Li, forming an acidic aqueous recycling feed of the battery waste material by leaching the battery waste material with an acid, the acidic aqueous recycling feed comprising one or more of Mn, Co, and Ni in solution at a pH <2; extracting one or more of Mn, Co, and Ni from the acidic aqueous recycling feed while maintaining the acidic aqueous recycling feed at a pH < 4 for all extraction steps; and after extracting one or more of Mn, Co, and Ni from the acidic aqueous recycling feed, recycling the acid from the acidic aqueous recycling feed for re-use in further leaching of battery waste material.

2. A method according to form 1 , wherein the solvent in which the Li is extracted is an organic acid, optionally formic acid, in which Li is soluble while Ni, Co, and Mn are insoluble.

3. A method according to form 1 , wherein Li-species in the battery waste material are reduced using a reductive thermal treatment prior to selectively dissolving the Li in the solvent, optionally an aqueous based solvent, optionally water.

4. A method according to any preceding form, wherein the pH of the acidic aqueous recycling feed formed by acid leaching the battery waste material is < 1.5, optionally < 1.0, optionally > 0.

5. A method according to any preceding form, wherein the acid used to form the acidic aqueous recycling feed comprises or consists of sulphuric acid.

6. A method according to any preceding form, wherein after forming the acidic aqueous recycling feed and prior to extracting one or more of Mn, Co, and Ni from the acidic aqueous recycling feed, the acidic aqueous recycling feed is subjected to one or more treatment steps to extract impurity elements including one or more of Al, Cu and Fe, the acidic aqueous recycling feed being maintained at a pH < 4, optionally < 3.5, optionally < 3.0, optionally > 2, during all of said one or more treatment steps.

7. A method according to form 6, wherein extraction media used to extract the impurity elements is regenerated and re- used to extract further impurity elements from the acidic aqueous recycling feed.

8. A method according to form 7, wherein the extraction media comprises a solid phase extraction media.

9. A method according to any preceding form, wherein the step of extracting one or more of Mn, Co, and Ni from the acidic aqueous recycling feed comprises contacting the acidic aqueous recycling feed with one or more organic solvent extraction compositions, stripping one or more of Mn, Co, and Ni from the one or more organic solvent extraction compositions, and recycling the one or more organic solvent extraction compositions for re-use in extracting further Mn, Co and/or Ni from the acidic aqueous recycling feed.

10. A method according to form 9, wherein the one or more organic solvent extraction compositions are treated with a base to regenerate the one or more organic solvent extraction compositions for re-use in extracting further Mn, Co and/or Ni from the acidic aqueous recycling feed.

11. A method according to form 9 or 10, wherein both Ni and Co are extracted into the same organic solvent extraction composition, and wherein the method further comprises selectively stripping the Ni and Co from the organic solvent extraction composition to produce two separate aqueous solutions, one comprising Ni and one comprising Co, prior to the organic solvent extraction composition being recycled for re-use in extracting further Co and Ni from the acidic aqueous recycling feed.

12. A method according to form 9, 10, or 11 , wherein Mn is extracted into a different organic solvent extraction composition than the Ni and Co.

13. A method according to any preceding form, wherein the acidic aqueous recycling feed is maintained at a pH < 3.5, optionally < 3, optionally > 2, during all extraction steps for Mn, Co, and/or Ni.

14. A method according to any preceding form, wherein the recycling of the acid from the acidic aqueous recycling feed for re-use in further leaching of battery waste material comprises a process to concentrate the acid.

While this invention has been particularly shown and described with reference to certain examples, it will be understood to those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as defined by the appended claims.