WO2023283685A1

WO2023283685A1 - Process for recovering values from alkaline batteries

Info

Publication number: WO2023283685A1
Application number: PCT/AU2022/050732
Authority: WO
Inventors: Andrew NAPIER; Andrew SKALSKI; Andrew Mackenzie
Original assignee: Resource Conservation and Recycling Corporation Pty Ltd
Priority date: 2021-07-16
Filing date: 2022-07-13
Publication date: 2023-01-19

Abstract

The present disclosure generally relates to processes for recovering and separating electrode materials from alkaline batteries, such as cathode and/or anode materials. The process comprises comminuting alkaline MMD to reduce the average particle size of the alkaline MMD to liberate and obtain a first particle fraction comprising cathode material and carbon and a second particle fraction comprising anode material; and separating and obtaining the first particle fraction comprising cathode material and carbon from the second particle fraction comprising anode material.

Description

PROCESS FOR RECOVERING VALUES FROM ALKALINE BATTERIES TECHNICAL FIELD

[0001] The present disclosure relates generally to processes for recovering values from alkaline batteries. More specifically, the present disclosure relates to processes for recovering and separating electrode materials from alkaline batteries, such as cathode and/or anode materials. The present disclosure also relates to compositions and products comprising cathode and/or anode materials recovered from alkaline batteries, including for example fertilisers and repurposed electrodes.

BACKGROUND

[0002] Modern alkaline batteries have been used to power small consumer and electronic applications since development in the late 1950’s. For example, alkaline batteries are used in personal devices, including toys, clocks, cameras and torches and other portable electronic devices.

[0003] As alkaline batteries reach their end of life, other than disposal into landfill, it is often desirable to recycle and dispose of them whilst recovering one or more values for on-sale and/or re-use. Current alkaline battery recycling often requires smelting or pyrometallurgical processing to extract one or more values. However, such processes often extract values as complex alloys with steel while additional valuable components are trapped as part of the slag phase and/or decomposed at the high temperature. As such, further processing of the slag material/alloys to obtain values requires high cost and additional processing steps.

[0004] Other recycling process include leaching shredded alkaline batteries with sulfuric acid to produce separated manganese and zinc as sulfated compounds. However, such recycling processes require specialist process equipment and expensive reagents.

[0005] Accordingly, there is a need for an alkaline battery recycling process which overcomes one or more of these disadvantages and/or provides the public with a useful alternative.

SUMMARY

[0006] The present inventors have undertaken research and development into processes for recovering one or more values from alkaline batteries, including for example cathode and/or anode materials. The present disclosure described herein can also be scalable for industrial application for processing and recycling large quantities of alkaline batteries and the recovered cathode and/or anode materials can be reused or repurposed across a variety of industries, including as repurposed electrode materials for cathodes and/or anodes in alkaline batteries, or as micronutrients for fertilisers.

[0007] Described herein is a process that can selectively separate and recover cathode material and carbon as a separate fraction to anode material from alkaline mixed metal dust (MMD). The alkaline MMD can be obtained from alkaline batteries, for example via physical separation (e.g. shredding). According to some examples or embodiments described herein, the inventors have identified that comminuting alkaline MMD can advantageously result in the liberation of cathode material and carbon as a separate fraction to the anode material, including for example a concentrated manganese oxide and carbon product.

[0008] In some embodiments, the cathode material and carbon may be separated from the anode material by subjecting the alkaline MMD to a froth flotation separation. In particular, according to some embodiments or examples, the inventors have surprisingly identified that cathode material and carbon report selectively report to the flotation concentrate as a separate fraction to the anode material. Comminution of alkaline MMD prior to froth flotation separation may also increase the recovery and concentration of the cathode material and carbon in the flotation concentrate. Another advantage of using froth flotation to separate the cathode material and carbon from the anode material according to some embodiments or examples described herein also include the preferential reporting of heavy metals to the anode material.

[0009] One or more downstream advantages associated with the processes described herein are also disclosed. For example, the separated cathode material and carbon can be processed into a fertiliser. Alternatively or additionally, the comminuted alkaline MMD particles comprising both the cathode material and carbon fraction and the anode material fraction can also be processed into a fertiliser. Alternatively, the separated cathode material and carbon and/or anode material can also be processed into one or more electrodes for use in alkaline batteries. Various advantages relating to the process, separated materials and products are described herein.

[0010] In one aspect, there is provided a process for obtaining cathode material and carbon from alkaline mixed metal dust (MMD) obtained from alkaline batteries, comprising: a) comminuting alkaline MMD to reduce the average particle size of the alkaline MMD to liberate and obtain a first particle fraction comprising cathode material and carbon and a second particle fraction comprising anode material; and b) separating the first particle fraction comprising cathode material and carbon from the second particle fraction comprising anode material.

[0011] In one embodiment, 80% of the comminuted alkaline MMD particles (Pso) have a particle size of between about 50 pm to about 500 pm.

[0012] In one embodiment, the first particle fraction comprises manganese oxide and carbon, and the second particle fraction comprises zinc/zinc oxide. The first particle fraction may be concentrated in manganese oxide and carbon and the second particle fraction may be concentrated in zinc/zinc oxide. In one embodiment, the first particle fraction has a higher % w/w concentration of manganese compared to the concentration of manganese in the second particle fraction, based on the total weight of the particle fraction. The first particle fraction may comprise between about 25% w/w to about 60 % w/w manganese based on the total weight of the first particle fraction. The first particle fraction may comprise between about 5% w/w to about 15% w/w carbon based on the total weight of the first particle fraction.

[0013] In one embodiment, the second particle fraction has a higher % w/w concentration of zinc compared to the concentration of zinc in the first particle fraction, based on the total weight of the particle fraction. The second particle fraction may comprise between about 20% w/w to about 70% w/w zinc, based on the total weight of the second particle fraction. In one embodiment, the carbon is physically or chemically associated with the manganese oxide as a mixed manganese oxide/carbon material. In one embodiment, the mixed manganese oxide/carbon material is a mixed MnC /MmCb/carbon material.

[0014] In one embodiment, the separating of the particle fractions at step b) comprises a size screening of the comminuted alkaline MMD particles. In an alternative embodiment, the separating of the particle fractions at step b) comprises froth flotation of the comminuted alkaline MMD particles.

[0015] In one embodiment, the separating of the particle fractions at step b) comprises performing a froth flotation separation on the comminuted alkaline MMD particles in a froth flotation vessel, wherein the first particle fraction comprising cathode material and carbon reports to a flotation concentrate, and second particle fraction comprising anode material reports to a flotation tail, and removing the flotation concentrate from the froth flotation vessel to separate and obtain the first particle fraction comprising cathode material and carbon.

[0016] In one embodiment, the flotation separation comprises: bl) suspending the comminuted alkaline MMD particles in an aqueous solution comprising one or more froth flotation agents in the froth flotation vessel to create a slurry; b2) aerating the slurry to generate air bubbles which float to the surface of the slurry to form a froth, wherein the first particle fraction comprising cathode material and carbon attaches to at least some of the air bubbles and floats to the top of the froth flotation vessel to report to the flotation concentrate, and the second particle fraction comprising anode material remains in the slurry to report to the flotation tail.

[0017] In one embodiment, the one or more froth flotation agents is selected from the group consisting of a frother, collector, and/or depressant. The frother may be an alcohol selected from the group consisting of methyl isobutyl carbinol (MIBC), 2-ethyl hexanol, isoamyl alcohol, cyclohexanol, a-terpinol, cresol, xylenol, glycol ether, and a combination thereof. The collector may be provided in an amount of between about 100 g/t to about 8000 g/t. The collector may be hydrocarbon oil, fatty acid or hydroximate. The hydrocarbon oil may be kerosene.

[0018] In one embodiment, after step bl) and prior to step b2), the slurry comprising the comminuted alkaline MMD particles is conditioned prior to froth flotation to clean or activate the particles prior to aeration. [0019] In one embodiment, the flotation tail comprising the second particle fraction is removed from the froth flotation vessel and undergoes gravity separation to recover any manganese and carbon entrained within the second particle fraction following froth flotation separation. In one embodiment, the manganese and carbon recovered from gravity separation is recycled into the froth flotation vessel or combined with the flotation concentrate.

[0020] In one embodiment, one or more heavy metals present in the comminuted alkaline MMD particles preferentially report to the flotation tail as part of the second particle fraction. In one embodiment, the flotation tail has a higher ppm concentration of heavy metal compared to the concentration of heavy metal in the flotation concentrate, based on the total weight of the reported particles.

[0021] In one embodiment, the alkaline MMD is provided by the steps: al) physically separating alkaline batteries to obtain coarser particles comprising steel and/or ferrous material and finer particles comprising alkaline MMD; and a2) separating the coarser particles comprising steel and/or ferrous material from the finer particles comprising alkaline MMD.

[0022] In one embodiment, the finer particles comprising alkaline MMD is between about 30% to about 80% w/w based on the total weight of the alkaline battery.

[0023] In one embodiment, step a2) comprises screening the separated alkaline battery particles at between about 4 mm to about 6 mm to separate the coarser particles comprising steel and/or ferrous material from the finer particle of alkaline MMD. In an alternative embodiment, step a2) comprises subjecting the separated alkaline battery particles to magnetic separation to separate the coarser particles comprising steel and/or ferrous material from the finer particles comprising alkaline MMD.

[0024] In one embodiment, the physical separation of the alkaline batteries at step al) produces a dust and/or fume comprising electrolyte, wherein the dust and/or fume is optionally treated to recover the electrolyte.

[0025] In one embodiment, the separated alkaline battery particles comprising coarser particles comprising steel and/or ferrous material and finer particles comprising alkaline MMD are washed and/or attritioned prior to step a2). Alternatively or additionally, the separated coarser particles comprising steel and/or ferrous material may be subjected to crushing to liberate and obtain alkaline MMD trapped within the coarser particles.

[0026] In one embodiment, the separated first particle fraction comprising cathode material and carbon and/or separated second particle fraction comprising anode material is processed into one or more electrodes for alkaline batteries.

[0027] In one embodiment, the process further comprises assembling an alkaline battery comprising one or more electrodes prepared using the separated first particle fraction comprising cathode material and carbon and/or separated second particle fraction comprising anode material.

[0028] In one embodiment, the process further comprises mixing the separated first particle fraction comprising cathode material and carbon at step b) with a phosphorous source and optionally a binder to prepare a fertiliser.

[0029] In one embodiment, the phosphorous source is a calcium phosphate salt or ammonium phosphate salt, or a combination thereof. The calcium phosphate salt may be monocalcium phosphate (Super Phosphate). The ammonium phosphate salt may be monoammonium phosphate (MAP) or diammonium phosphate (DAP), or a combination thereof. The binder may be phosphoric acid.

[0030] In another aspect, there is provided use of the separated first particle fraction comprising cathode material and carbon obtained by the process as described above, as a micronutrient in fertiliser.

[0031] In another aspect, there is provided a fertiliser comprising comminuted alkaline MMD particles or separated cathode material and carbon obtained from alkaline batteries, a phosphorous source, and optionally a binder.

[0032] In another aspect, there is provided an alkaline battery comprising one or more electrodes prepared using the separated cathode material and carbon and/or anode material obtained by the processes described above.

[0033] In another aspect, there is provided use of the separated first particle fraction comprising cathode material and carbon and/or anode material obtained by the process described above, as an electrode material for preparing one or more electrodes for alkaline batteries.

[0034] It will be appreciated that other aspects, embodiments and examples of the processes and materials are described herein.

BRIEF DESCRIPTION OF FIGURES

[0035] Notwithstanding any other forms which may fall within the scope of the process described herein, specific embodiments will now be described, by way of example only, with reference to the accompanying figures in which:

[0036] Figure 1: Process flow sheet depicting a process for liberating and obtaining cathode, carbon and anode materials from alkaline batteries using physical separation.

[0037] Figure 2: Process flow sheet depicting a process for obtaining cathode, carbon and anode materials from alkaline batteries using physical separation, with dust and fume treatment for electrolyte recovery.

[0038] Figure 3: Process flow sheet depicting a process for obtaining cathode, carbon and anode materials from alkaline batteries using flotation. [0039] Figures 4: Process flow sheet depicting a process for obtaining cathode, carbon and anode materials from alkaline batteries using gravity separation.

[0040] Figure 5: Process flow sheet depicting a process for obtaining cathode, carbon and anode materials from alkaline batteries using comminution and froth flotation.

[0041] Figure 6 and 7: Process flow sheets depicting a process for obtaining cathode, carbon and anode materials products from alkaline batteries using combinations of froth flotation and gravity separation.

[0042] Figure 8: Process flow sheet depicting a process for preparing a fertiliser using separated cathode material and carbon as a micronutrient.

DETAILED DESCRIPTION

[0043] The present disclosure describes the following various non-limiting embodiments, which relates to investigations undertaken to identify processes for recovering one or more values from alkaline batteries.

General terms

[0044] In the following description, reference is made to the accompanying drawings which form a part hereof, and which is shown, by way of illustration, several embodiments. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure.

[0045] With regards to the definitions provided herein, unless stated otherwise, or implicit from context, the defined terms and phrases include the provided meanings. Unless explicitly stated otherwise, or apparent from context, the terms and phrases below do not exclude the meaning that the term or phrase has acquired by a person skilled in the relevant art. The definitions are provided to aid in describing particular embodiments, and are not intended to limit the claimed invention, because the scope of the invention is limited only by the claims. Furthermore, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0046] All publications discussed and/or referenced herein are incorporated herein in their entirety.

[0047] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

[0048] Throughout this disclosure, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms “a”, “an” and “the” include plural aspects unless the context clearly dictates otherwise. For example, reference to “a” includes a single as well as two or more; reference to “an” includes a single as well as two or more; reference to “the” includes a single as well as two or more and so forth.

[0049] Those skilled in the art will appreciate that the disclosure herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the examples, steps, features, methods, compositions, coatings, processes, and coated substrates, referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0051] The term “and/or”, e.g., “X and/or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0052] The reference to “substantially free” generally refers to the absence of that compound or component in the material (e.g. absence of a particular impurity in the first or second particle fractions, cathode or anode materials, flotation concentrate or tail) other than any trace amounts or impurities that may be present, for example this may be an amount by weight % in the total composition of less than about 1%, 0.1%, 0.01%, 0.001%, or 0.0001%., or an amount as ppm in the total composition of less than about 10000, 1000, 100, 10 or 1 ppm.

[0053] Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of lower-numbered item (e.g., a “first” item) and/or a higher-numbered item (e.g., a “third” item).

[0054] As used herein, the phrase “at least one of’, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the fist may be needed. The item may be a particular object, thing, or category. In other words, “at least one of’ means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. For example, “at least one of item A, item B, and item C” may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, “at least one of item A, item B, and item C” may mean, for example and without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

[0055] As used herein, the term “about”, unless stated to the contrary, typically refers to +/- 10%, for example +/- 5%, of the designated value.

[0056] It is to be appreciated that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub combination.

[0057] Throughout the present specification, various aspects and components of the invention can be presented in a range format. The range format is included for convenience and should not be interpreted as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range, unless specifically indicated. For example, description of a range such as from 1 to 5 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5 etc., as well as individual and partial numbers within the recited range, for example, 1, 2, 3, 4,

5, 5.5 and 6, unless where integers are required or implicit from context. This applies regardless of the breadth of the disclosed range. Where specific values are required, these will be indicated in the specification.

[0058] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0059] Each example of the present disclosure described herein is to be applied mutatis mutandis to each and every other example unless specifically stated otherwise. The present disclosure is not to be limited in scope by the specific examples described herein, which are intended for the purpose of exemplification only. Functionally equivalent products, compositions and methods are clearly within the scope of the disclosure as described herein.

Specific terms

[0060] As used herein, the term “electrode material” refers to a material comprising either anode material, cathode material or a mixture thereof. In the context of the present disclosure, the electrode material is obtained from alkaline batteries, and comprise or consist of a mixed metal material.

[0061] As used herein, the term “cathode material” and “anode material” refers to the active material used to prepare the cathode and anode (i.e. electrodes) of an alkaline battery, respectively. Reference to active material means the material of the cathode and anode that react with each other during discharge of the alkaline battery, for example as outlined in the half reactions and overall reaction outlined below... Embodiments of the cathode and anode material and other metals are described herein.

[0062] As used herein, the term “mixed metal” includes a compound or mixture comprising at least two metals. By way of example, where the mixed metal material is obtained during the recycling of alkaline batteries, the mixed metal material may comprise one or more metals that are present in alkaline batteries, such as those present in the electrodes, including cathode and anode materials. As an example, the metals in the mixed metal material may comprise manganese and zinc, for example as cathode and anode material. Other non-limiting examples of metals in the mixed metal material can include aluminium, carbon, copper, iron, potassium, sodium, and titanium. The mixed metal material may be a mixed metal dust (MMD) (also referred to as a mixed metal oxide dust and “black mass”). In some embodiments, the MMD may be obtained during the recycling of alkaline batteries. The MMD may be a blend of one or more cathode and anode materials obtained from alkaline batteries along with one or more other metals described herein (e.g. carbon), also referred to herein as alkaline MMD. The mixed metal material may comprise a plurality of particles.

[0063] A reference to “mg/kg” throughout the specification refers to the mass (in milligram) of a substance per kilogram of the total weight of a composition. A reference to w/w” throughout the specification refers to the percentage amount of a substance in a composition on a weight basis.

[0064] As used herein, the term “comminuting” and related terms such as “comminuted”, “comminution” etc. refers to the reduction of a solid material from one average particle size to a smaller average particle size, for example by crushing, grinding or milling.

Process for recovering values from alkaline batteries

[0065] The process described herein can recover one or more values from alkaline batteries, namely materials that make up the cathode and anode of an alkaline battery. An alkaline battery is a type of primary battery which derives its energy from a chemical reaction between manganese oxide (i.e. cathode material) and zinc/zinc oxide (i.e. anode material) via an alkaline electrolyte.

[0066] An alkaline battery comprises a cathode (e.g. positive terminal) and an anode (e.g. negative terminal). The cathode and anode comprise cathode material and anode material, respectively. The cathode material comprises a manganese oxide (e.g. MnCk and/or MmCb), often provided as a compressed paste to form the cathode. Carbon is often added to the cathode material (e.g. in the form of graphite) to increase the conductivity of the cathode, but does not take part in the half-reaction at the cathode or overall reaction on discharge (see below). The anode material comprises a mixture of zinc and zinc oxide (e.g. ZnO). It will be appreciated that the alkaline MMD described herein comprises a mixture of both the cathode material and anode material, and one or more other metal values obtained from alkaline batteries. [0067] The half-reactions at the anode and cathode comprising the anode material and cathode material, respectively, are:

Zii_(s) + 2 OH _(aq) ZnO_(s) + EhOa₎ + 2e (anode)

2Mn0_2(S) + tbO_® + 2e - dVhi203_(S) + 20H _(aq) (cathode)

[0068] Overall, the reaction is:

Zn_(S) + 2Mn02_(S) ^ ZnO_(S> + M Chw

[0069] Alkaline batteries require an electrolyte which is dispersed with the anode material (and in some cases the cathode material). The electrolyte is alkaline and promotes the movement of electrons from the anode to the cathode on discharge. A typical alkaline electrolyte is potassium hydroxide (KOH).

[0070] The cathode material and anode material independently form the reactive components of the cathode (i.e. positive electrode) and the anode (i.e. negative electrode), respectively, of the alkaline battery. The cathode and anode are separated by a separator which is a material located between the cathode and anode to keep the two electrodes apart to prevent electrical short circuits while also allowing the transport of ions therethrough. Examples of separator materials include polymers (e.g. polyolefins such as polyethylene, polypropylene and blends thereof).

[0071] Other materials also present in alkaline batteries include the outer casing and/or auxiliary components, including current collection or connection devices such as brass and aluminium, along with steel and ion conducting separator, typically woven cellulose or a synthetic polymer. Aluminium and/or plastics or cardboard are often used to house/encase alkaline batteries and for other auxiliary functions such as wiring.

[0072] The alkaline batteries may be end of life batteries (e.g. dead/spent or faulty). It will be appreciated that such batteries present little economic value in their current form (e.g. cannot be sold). In light of the numerous materials making up alkaline batteries, there is a need to develop processes to recover a least some of these materials for re-use, recycling and/or commercial sale rather than disposing to landfill.

[0073] In one embodiment, the alkaline batteries have been physically separated to obtain alkaline MMD. The alkaline MMD may be subjected to a comminuting step as described herein.

[0074] In some aspects or embodiments, the present inventors have developed a process in which alkaline MMD obtained from alkaline batteries is subjected to a comminution step as described herein which results in the selective separation and recovery of cathode material and carbon as a separate fraction to the anode material, including for example a concentrated manganese oxide and carbon product. The cathode material and carbon can be separated from the anode material fraction (for example by froth flotation) and in some embodiments can be commercially sold as a carbon enriched manganese oxide product and/or subjected to further processing as a micronutrient for fertilisers. The anode material fraction can also be commercially sold. Importantly, according to some embodiments or examples described herein, the process described herein does not require smelting, pyrometallurgical processing or acidic leaching to separate and obtain the cathode and anode material.

[0075] In some embodiments, the process for obtaining cathode material and carbon from alkaline MMD obtained from alkaline batteries, comprises the steps of a) comminuting alkaline MMD to reduce the average particle size of the alkaline MMD to liberate and obtain a first particle fraction comprising cathode material and carbon and a second particle fraction comprising anode material.

Comminuting alkaline MMD

[0076] The alkaline MMD may be comminuted to reduce the average particle size of the alkaline MMD particles. The alkaline MMD may be comminuted by any conventional physical processing technique, including for example grinding, crushing, attritioning, shredding and/or milling. Any suitable apparatus capable of comminuting the alkaline MMD can be used, for example a grinding mill (either rod or ball), crusher, agitator (e.g. a high intensity agitator or an agitator tank), all of which are known to the person skilled in the art.

[0077] The comminuting step may be performed in the presence of a liquid (e.g. wet comminution) or may be performed under dry conditions. In one embodiment, the comminuting step comprises dry or wet grinding of the alkaline MMD, for example dry grinding.

[0078] The comminuted alkaline MMD particles (comprising the first and second particle fractions described herein) have an average particle size. The average particle size is taken to be the cross-sectional diameter across a particle. For non-spherical particles, the particle size is taken to be the distance corresponding to the longest cross- section dimension across the particle. It will be appreciated that the average particle size of the comminuted alkaline MMD is smaller than the average particle size of the alkaline MMD prior to the comminution step.

[0079] The comminution step can result in a size reduced alkaline MMD. In one embodiment, the comminution of alkaline MMD can result in 80% of the comminuted alkaline MMD particles (Pso) having a particle size of between about 50 pm to about 500 pm. The comminution of alkaline MMD can result in 80% of the comminuted alkaline MMD particles (Pso) having a particle size of less than about 500, 450, 400, 350. 300, 250, 150, 100 or 50 pm. The comminution of alkaline MMD can result in 80% of the comminuted alkaline MMD particles (Pso) having a particle size of at least about 50, 100, 150, 250, 300, 350, 400, 450 or 500 pm. The comminution of alkaline MMD can result in 80% of the comminuted alkaline MMD particles (Pso) having a particle size in a range provided by any two of these upper and/or lower amounts, for example between about 50 pm to about 500 pm. By comminuting the alkaline MMD particles, one or more advantages may be provided according to at least some embodiments or examples described herein, including increased recovery of carbon into the first particle fraction comprising cathode material. [0080] The alkaline MMD particles may be comminuted for any period of time effective to obtain one or more of the reduce particle sizes described herein, which may vary depending on the scale of the comminution (e.g. at laboratory scale or industrial scale) as understood by the skilled person when performing comminution. In some embodiments, the comminution of the alkaline MMD is for a period of time of between about 1 minute to 120 minutes. The comminution of the alkaline MMD may be for a period of time (in minutes) of at least about 1, 2, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100 or 120. The comminution of the alkaline MMD may be for a period of time (in minutes) of less than about 120, 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, 10, 5, 2 or 1.

The comminution times can be a range provided by any two of these upper and/or lower times, for example between about 5 minutes to about 30 minutes, or about 5 minutes to about 15 minutes, or 30 minutes to about 60 minutes.

[0081] The comminuted alkaline MMD particles may vary in morphology. The particles may take the form of flakes, fibres, agglomerates, granules, powders, spheres, pulverized materials or the like, as well as combinations thereof. The particles may have any desired shape including, but not limited to, cubic, rod like, polyhedral, spherical or semi- spherical, rounded or semi-rounded, angular, irregular, and so forth.

[0082] The particle morphology and particle size can be measured by any conventional method, including laser diffraction, electron microscopy, dynamic light scattering, optical microscopy or size exclusion methods (such as wet or dry graduated mesh screens or filters).

[0083] The comminution of alkaline MMD liberates and obtains a first particle fraction comprising cathode material and carbon and a second particle fraction comprising anode material. It will be appreciated that the first particle fraction and second particle fraction form part of the overall comminuted alkaline MMD particles described herein.

First particle fraction

[0084] The first particle fraction comprises cathode material and carbon. The cathode material comprises a manganese oxide. The manganese may exist in several oxidation states, including Mn(II) and Mn(III). In some embodiments, the manganese oxide may be manganese (II) oxide (MnCh), manganese (III) oxide (MmCF) or a mixture thereof. It will be appreciated that any reference to manganese oxide, unless otherwise specified, can encompass one or more manganese oxide phases, including those recited above as well as mixtures thereof.

[0085] The carbon may be associated with the manganese oxide (as opposed to discrete particles of carbon dispersed with the manganese oxide). The association may be physical or chemical. In one embodiment, the carbon is physically or chemically associated with the manganese oxide. The carbon may be physically or chemically associated with the manganese oxide as a mixed manganese oxide/carbon material. In one embodiment, the first particle fraction comprises a mixed manganese oxide/carbon material. The mixed manganese oxide/carbon material may be a mixed MnC /MmCF/carbon material. It will be appreciated that the mixed manganese oxide/carbon material is a compound comprising carbon physically associated with the manganese oxide as opposed to a mixture of discrete manganese oxide separate to carbon.

[0086] The first particle fraction may be concentrated in manganese oxide and carbon. As used herein, the term “concentrated” refers to the enrichment of an element/compound in the particle fraction compared to the alkaline MMD prior to comminution.

[0087] In some embodiments, the first particle fraction has a higher % w/w concentration of manganese (e.g. elemental manganese derived from the manganese oxide present in the first particle fraction) compared to the concentration of manganese in the second particle fraction, based on the total weight of the particle fraction.

[0088] In some embodiments, the first particle fraction has a manganese % distribution of between about 40% to about 95% based on the amount of manganese in the alkaline MMD prior to comminution. The first particle fraction may have a manganese % distribution (based on the amount of manganese in the alkaline MMD prior to comminution) of at least about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95. The first particle fraction may have a manganese % distribution (based on the amount of manganese in the alkaline MMD prior to comminution) of less than about 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, or 40. The first particle fraction may have a manganese % distribution in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 80% to about 90% based on the amount of manganese in the alkaline MMD prior to comminution.

[0089] In some embodiments, the first particle fraction has a higher % w/w concentration of carbon (e.g. elemental carbon present in the first particle fraction) compared to the concentration of carbon in the second particle fraction, based on the total weight of the particle fraction.

[0090] In some embodiments, the first particle fraction has a carbon % distribution of between about 40% to about 95% based on the amount of carbon in the alkaline MMD prior to comminution. The first particle fraction may have a carbon % distribution (based on the amount of carbon in the alkaline MMD prior to comminution) of at least about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95. The first particle fraction may have a carbon % distribution (based on the amount of carbon in the alkaline MMD prior to comminution) of less than about 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, or 40. The first particle fraction may have a carbon % distribution in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 80% to about 90% based on the amount of carbon in the alkaline MMD prior to comminution.

[0091] In some embodiments, the first particle fraction comprises between about 10% w/w to about 60% w/w manganese based on the total weight of the first particle fraction. The first particle fraction may comprise manganese in an amount (as a % w/w based on the total weight of the first particle fraction) of at least about 10, 15, 20, 25,

30, 35, 40, 45, 50, 55 or 60. The first particle fraction may comprise manganese in an amount (as a % w/w based on the total weight of the first particle fraction) of less than about 60, 55, 50, 45, 40, 35, 30, 25, 20, 15 or 10. The first particle fraction may comprise manganese in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 25% w/w to about 50% w/w, or about 35% w/w to about 45% w/w manganese based on the total weight of the first particle fraction.

[0092] In some embodiments, the first particle fraction comprises between about 1% w/w to about 30% w/w carbon based on the total weight of the first particle fraction. The first particle fraction may comprise carbon in an amount (as a % w/w based on the total weight of the first particle fraction) of at least about 1, 2, 3, 4, 5, 7, 10, 12, 15, 20, 25 or 30. The first particle fraction may comprise carbon in an amount (as a % w/w based on the total weight of the first particle fraction) of less than about 30, 25, 20, 15, 12, 10, 5, 2 or 1. The first particle fraction may comprise carbon in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 5% w/w to about 15% w/w, or about 7% w/w to about 12% w/w carbon based on the total weight of the first particle fraction.

Second particle fraction

[0093] The second particle fraction comprises anode material. The anode material comprises zinc metal and zinc oxide (ZnO), also referred to as zinc/zinc oxide.

[0094] The second particle fraction may be concentrated in zinc/zinc oxide. In some embodiments, the second particle fraction has a higher % w/w concentration of zinc (e.g. elemental zinc derived from the zinc metal and/or zinc oxide) compared to the concentration of zinc in the first particle fraction, based on the total weight of the particle fraction.

[0095] In some embodiments, the second particle fraction has a zinc % distribution of between about 20% to about 60% based on the amount of zinc in the alkaline MMD prior to comminution. The second particle fraction may have a zinc % distribution (based on the amount of zinc in the alkaline MMD prior to comminution) of at least about 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58 or 60. The second particle fraction may have a zinc % distribution (based on the amount of zinc in the alkaline MMD prior to comminution) of less than about 60, 58, 56, 54, 52, 50, 48, 46, 44, 42, 40, 38, 36, 34, 32, 30, 28, 26, 24, 22 or 20. The second particle fraction may have a zinc % distribution in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 30% to about 50% based on the amount of zinc in the alkaline MMD prior to comminution.

[0096] In some embodiments, the second particle fraction has a lower % w/w concentration of carbon compared to the concentration of carbon in the first particle fraction, based on the total weight of the particle fraction.

[0097] In some embodiments, the second particle fraction has a carbon % distribution of between about 1% to about 60% based on the amount of carbon in the alkaline MMD prior to comminution. The second particle fraction may have a carbon % distribution (based on the amount of carbon in the alkaline MMD prior to comminution) of at least about 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60. The second particle fraction may have a carbon % distribution (based on the amount of carbon in the alkaline MMD prior to comminution) of less than about 60, 55, 50, 45,

40, 35, 30, 25, 20, 15, 10, 5, 2, or 1. The second particle fraction may have a carbon % distribution in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 5% to about 15% based on the amount of carbon in the alkaline MMD prior to comminution.

[0098] In some embodiments, the second particle fraction comprises between about 10% w/w to about 60 % w/w zinc based on the total weight of the second particle fraction. The second particle fraction may comprise zinc in an amount (as a % w/w based on the total weight of the second particle fraction) of at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60. The second particle fraction may comprise zinc in an amount (as a % w/w based on the total weight of the second particle fraction) of less than about 60, 55, 50, 45, 40, 35, 30, 25, 20, 15 or 10. The second particle fraction may comprise zinc in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 20% w/w to about 60% w/w, or about 25% w/w to about 40% w/w zinc based on the total weight of the second particle fraction.

[0099] The amount of manganese, carbon and/or zinc, and other metals present in the alkaline MMD particles, including the first and second particle fractions may be determined using any suitable elemental compositional analysis technique, including for example one or more head assay analyses, including ashing, fusion, mixed acid digestion, Inductively coupled plasma - optical emission spectrometry (ICP-OES) , Inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF) or thermal analysis for carbon (such as Leco or CS2000).

[0100] The process may further comprise b) separating the first particle fraction comprising cathode material and carbon from the second particle fraction comprising anode material which are generated by the comminution of the alkaline MMD. The separating of the particle fractions at step b) may comprise a size screening or froth flotation of the comminuted alkaline MMD particles.

[0101] The comminuted alkaline MMD particles may be size screened to separate the first particle fraction. The first particle fraction may be separated from the comminuted alkaline MMD particles via size-screening between about 30 pm to about 200 pm. The first particle fraction may be separated from the comminuted alkaline MMD particles via size screening below about 200, 180, 160, 140, 120, 100, 90, 80, 75, 70, 65, 60, 55, 40, 35 or 30 pm. Combination of these values can provide a range selection, for example between about 50 pm to about 100 pm.

Froth flotation separation

[0102] In one embodiment, the separating of the particle fractions described herein comprise froth flotation of the alkaline MMD particles. [0103] Froth flotation involves the separation of the particle fractions based on their surface properties, namely their hydrophobic or hydrophilic properties. Generally speaking, hydrophilic surfaces will tend to associate with water (or another suitable aqueous phase) while hydrophobic surfaces will associate with a non-aqueous phase, for example air bubbles. Froth flotation separation exploits these surface properties to separate materials.

[0104] Froth flotation processes are performed in a suitable froth flotation vessel (also called a cell or tank). The froth flotation vessel may be rectangular or cylindrical mechanically or naturally aerated vessels, flotation columns or cells. One or more froth flotation vessels/cells may be used, for example arranged in a series of cascading vessels/cells.

[0105] Separation of the particle fractions is achieved as air bubbles float to the surface of the froth flotation vessel carrying away the hydrophobic cathode material and carbon while the anode material remains suspended in the aqueous solution. The particles that attach to the air bubbles and float to the surface of the vessel forming a froth are referred to as the flotation concentrate. Often, the flotation concentrate comprises particles that are more hydrophobic compared to the particles which have reported to the flotation tail, which are generally more hydrophilic.

[0106] When an aqueous slurry of alkaline MMD particles in the froth flotation vessel are aerated with bubbles, the hydrophobic particles attach to at least some of the air bubbles and floats to the top of the froth flotation vessel to report to a flotation concentrate, and the hydrophilic particles remains in the slurry to report to a flotation tail.

[0107] In one embodiment, the separating of the particle fractions at step b) comprises performing a froth flotation separation on the comminuted alkaline MMD particles in a froth flotation vessel. In one embodiment, the first particle fraction comprising cathode material and carbon reports to a flotation concentrate, and second particle fraction comprising anode material reports to a flotation tail. In one embodiment, the process further comprises removing the flotation concentrate from the froth flotation vessel to separate and obtain the first particle fraction comprising cathode material and carbon.

[0108] In one embodiment, the froth flotation separation comprises: bl) suspending the comminuted alkaline MMD particles in an aqueous solution comprising one or more froth flotation agents in the froth flotation vessel to create a slurry; t>2) aerating the slurry to generate air bubbles which float to the surface of the slurry to from a froth, wherein the first particle fraction comprising cathode material and carbon attaches to at least some of the air bubbles and floats to the top of the froth flotation vessel to report to the flotation concentrate, and the second particle fraction comprising anode material remains in the slurry to report to the flotation tail.

[0109] According to some embodiments or examples, the froth flotation processes described herein exploits carbons inherent hydrophobic properties to preferentially float manganese oxide (i.e. cathode material) separate to the zinc/zinc oxide (i.e. anode material), as opposed to recovering carbon as a separate material to the electrode material. By carefully controlling the comminution of alkaline MMD particles, along with liberating particle fractions comprising the anode and cathode material, carbon remains physically or chemically associated with the manganese oxide. Owing to carbons inherent hydrophobicity, it attaches to the air bubbles and carries with it the cathode material to the surface thus greatly assisting in separation of the cathode material from the anode material which remains in the flotation tail. In some embodiments, a prolonged comminution of the alkaline MMD particles destroyed the manganese oxide and carbon association, thus allowing some of the liberated cathode material to migrate to the flotation tail along with the anode material owing to manganese oxide being inherently hydrophilic, thus reducing recovery of manganese in the flotation concentrate. Accordingly, in some embodiments or examples, the inventors have surprisingly identified that comminuting the alkaline MMD to a reduced particle size (for example to between about 50 pm to about 300 pm) increases the recovery of manganese oxide and carbon in the floatation concentrate separate to the anode material of zinc/zinc oxide. One or more downstream advantages of this effective separation are described herein.

[0110] The flotation concentrate may comprise the first particle fraction as described herein. It will be appreciated that the manganese and carbon % distribution and % w/w concentration of the first particle fraction as described herein equally apply to the manganese and carbon % distribution and % w/w concentration of the flotation concentrate. In some embodiments, owing to the presence of the first particle fraction, the flotation concentrate is concentrated in manganese oxide and/or carbon. In some embodiments, the flotation concentrate has a higher % w/w concentration of manganese and/or carbon compared to the concentration of manganese and/or carbon in the flotation tail, based on the total weight of the reported particles. In some embodiments, the flotation concentrate may have a higher % w/w concentration of carbon compared to the concentration of carbon in the flotation tail, based on the total weight of the reported particles.

[0111] The particles that do not attach to the air bubbles and float to the surface of the vessel are referred to as the flotation tail. Often, the flotation tail comprises particles that are more hydrophilic compared to the particles which have reported to the flotation concentrate, which are generally more hydrophobic. The particles of the flotation tail may be subjected to further processing (i.e. attritioning) and further froth flotation steps to recover hydrophobic particles (e.g. cathode material and carbon) that did not initially float. This process is known as scavenging. In one embodiment, the process further comprises one or more additional froth flotation separation steps to recover cathode material and carbon from the flotation tail.

[0112] The flotation tail may comprise the second particle fraction as described herein. It will be appreciated that the zinc and carbon % distribution and % w/w concentration of the second particle fraction as described herein equally apply to the zinc and carbon % distribution and % w/w concentration of the flotation tail. In some embodiments, owing to the presence of the second particle fraction, the flotation tail is concentrated in zinc/zinc oxide. In some embodiments, the flotation tail has a higher % w/w concentration of zinc compared to the concentration of zinc in the flotation concentrate, based on the total weight of the reported particles. In some embodiments, the flotation tail has a lower % w/w concentration of carbon compared to the concentration of carbon in the particles of the flotation concentrate, based on the total weight of the reported particles.

[0113] Occasionally, the alkaline MMD may comprise one or more heavy metals because of other battery types (e.g. lithium-ion, lead batteries etc.) misreporting to the alkaline battery feed which is then physically separated to obtain the alkaline MMD. The present inventors have surprisingly identified that, according to some embodiments or examples described herein, one or more heavy metals present in the comminuted alkaline MMD particles preferentially report to the flotation tail as part of the second particle fraction (i.e. with the anode material). The one or more heavy metals include for example lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg).

[0114] In some embodiments, the flotation tail has a higher ppm concentration of heavy metal (e.g. Cd, Pb etc.) compared to the concentration of heavy metal in the flotation concentrate, based on the total weight of the reported particles.

[0115] The flotation tail may comprise one or more heavy metals in an amount of between about 100 ppm to about 500 ppm based on the total weight of the reported particles. The flotation tail may have a heavy metal concentration (as ppm based on the total weight of the reported particles) of at least about 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480 or 500. The flotation tail may have a heavy metal concentration in an amount in a range provided by any two of these amounts, for example between about 100 ppm to about 300 ppm, based on the total weight of the reported particles.

[0116] The flotation concentrate may comprise one or more heavy metals in an amount of between about 1 ppm to about 200 ppm based on the total weight of the reported particles. The flotation concentrate may have a heavy metal concentration (as ppm based on the total weight of the reported particles) of less than about 200, 150,

100, 80, 70, 60, 50, 40, 30, 20, 10, 5, or 1. The flotation concentrate may have a heavy metal concentration in an amount in a range provided by any two of these amounts, for example between about 50 ppm to about 100 ppm, based on the total weight of the reported particles.

[0117] By preferentially reporting any heavy metal present in the alkaline MMD to the flotation tail with the anode material, in some embodiments, the cathode material enriched with carbon can be readily processed into a fertiliser with higher % manganese and carbon content.

[0118] The froth flotation separation comprises suspending the comminuted alkaline MMD particles in an aqueous solution, optionally comprising one or more froth flotation agents in the froth flotation vessel to create a slurry. Froth flotation agents comprise one or more materials that are suitable to manipulate the hydrophobic and/or hydrophilic properties of the suspended comminuted alkaline MMD particles to facilitate separation and/or assist in froth generation. The aqueous slurry and optional froth flotation agents may also be referred to as a “pulp”. [0119] Any froth flotation agent that facilitates in the separation of the particle fractions by rendering the surfaces thereof more hydrophobic and/or more hydrophilic relative to each other so that the hydrophobic material attaches to air bubbles and floats to report to the flotation concentrate while the hydrophilic particles remain in the aqueous solution and report to the flotation tail can be used. In some embodiments, the one or more froth flotation agents is selected from the group consisting of a frother, collector and/or depressant. For example, a collector may be added to the aqueous solution comprising suspended alkaline MMD particles, which physically or chemically absorbs to the first particle fraction to increase the hydrophobicity of the particles and promote attachment to the air bubbles generated. Alternatively or additionally a depressant may be added, which physically or chemically absorbs to the second particle fraction to increase the hydrophilicity of the particles.

[0120] In one embodiment, the aqueous solution comprising suspended comminuted alkaline MMD particles also comprises a frother and a collector, and optionally a depressant.

[0121] In one embodiment the frother is an alcohol. In one embodiment, the frother is an alcohol selected from the group consisting of methyl isobutyl carbinol (MIBC), 2- ethyl hexanol, isoamyl alcohol, cyclohexanol, a-terpinol, cresol, xylenol, glycol ether, and a combination thereof. In one embodiment, the frother is methyl isobutyl carbinol (MIBC). The frother may be added in an amount effective to assist in stabilising the froth formed by the air bubbles at the surface of the slurry, as known to the skilled person.

[0122] A collector may be added to enhance the hydrophobicity of the first particle fraction comprising carbon and cathode material. Suitable collectors include a hydrocarbon oil (e.g. kerosene), fatty acids (e.g. oleic acid) and hydroximates (e.g. hydroxamic acid). In one embodiment, the collector is a hydrocarbon oil. In one embodiment, the hydrocarbon oil is kerosene.

[0123] The collector may be added in an amount effective to manipulate the surface of the first particle to be more hydrophobic, thereby promoting attachment to the air bubbles during aeration. In some embodiment, the collector is provided in an amount of between about 100 g/t to about 8000 g/t. The collector may be provided in an amount (in g/t) of at least about 100, 200, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000,

4500, 5000, 5500, 6000, 6500, 7000, 7500 or 8000. The collector may be provided in an amount (in g/t) of less than about 8000, 7500, 7000, 6500, 6000, 5500, 5000, 4500, 4000, 3500, 3000, 2500, 2000, 1500, 1000, 500, 200 or 100. The collector may be provided in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 500 g/t to about 2000 g/t.

[0124] In some embodiments, owing to the carbon present in the first particle fraction, little or no collector is required to manipulate the hydrophobic properties of the first particle fraction owing to the inherent hydrophobic nature of the carbon. However, it will be appreciated that any addition of a collector may be advantageous to further enhance the inherent hydrophobicity of the first particle fraction comprising carbon and cathode material to facilitate separation from the anode material via froth flotation.

[0125] The aqueous slurry comprising comminuted alkaline MMD particles, and optionally one or more froth flotation agents, is then aerated (i.e. sparged with air) to generate air bubbles. In the froth flotation vessel, hydrophobic particles attach to at least some of the air bubbles and float to the top of the froth flotation vessel to form a froth for removal versus the hydrophilic particles which remain in the aqueous slurry.

In this way, particles having different surface properties (e.g. hydrophobic vs hydrophilic) are separated from one and other.

[0126] The aqueous slurry may be aerated at flow rate effective to generate sufficient air bubbles and froth to separate the particle fraction. The flow rate may be at a rate suitable for industrial scale separation, as understood by the person skilled in the art.

[0127] The aqueous slurry may be aerated for a period of time effective to generate sufficient air bubbles and froth to separate the particle fraction. In some embodiments, the aeration of the aqueous slurry may be for a period of time of between 10 minutes to about 24 hours. The aeration of the aqueous slurry may be for a period of time of at least 1, 5, 10, 15, 20, 30, 45 (minutes), 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 18, or 24 hours. The aeration of the aqueous slurry may be for a period of time of less than 24,

18, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.5, 1 (hours), 45, 30, 20, 15, 10, 5 or 1 (minutes). The aeration times may be provided by any two of these upper and/or lower amounts.

[0128] The pH of the aqueous slurry may be any suitable pH. In one embodiment, the pH of the aqueous slurry is the slurry’s natural pH (i.e. the pH of the slurry once the comminuted alkaline MMD particles and optional froth flotation agents are added). In some embodiments, the pH of the aqueous slurry is between about 8 to about 14, for example between about 10 to about 13.

[0129] In some embodiments, the aqueous slurry comprising the comminuted alkaline MMD particles is conditioned prior to froth flotation to clean or activate the particles prior to aeration. Such conditioning may enhance the particles inherent hydrophobic/hydrophilic properties and facilitate in separation of the cathode and anode material.

[0130] The flotation concentrate and/or tail can be removed from the flotation vessel by any conventional means to separate and obtain the first particle fraction of cathode material and carbon. For example, the flotation concentrate can be removed by skimming off the froth using a mechanical propeller located at the slurry surface. The flotation tail can be removed via a suitable outlet valve or pump located below the surface of the slurry.

[0131] In some embodiments, the flotation tail comprising the second particle fraction is removed from the froth flotation vessel and undergoes gravity separation to recover any manganese and carbon entrained within the second particle fraction following froth flotation separation. The manganese and carbon recovered from gravity separation can be recycled into the froth flotation vessel or combined with the flotation concentrate. [0132] In some embodiments, the comminuted alkaline MMD particles undergoes gravity separation to recover a light fraction comprising cathode material and carbon and a heavy fraction comprising anode material, wherein the light fraction comprising cathode material and carbon undergoes froth flotation separation.

Alkaline mixed metal dust (MMD)

[0133] The alkaline MMD may be obtained from alkaline batteries by any physical separation means, including for example conventional break operations to mechanically comminute the alkaline battery.

[0134] The alkaline MMD may comprise one or more particulates (e.g. particles). The particles may take the form of flakes, fibres, agglomerates, granules, powders, spheres, pulverized materials or the like, as well as combinations thereof. The particles may have any desired shape including, but not hmited to, cubic, rod hke, polyhedral, spherical or semi- spherical, rounded or semi-rounded, angular, irregular, and so forth.

[0135] The alkaline MMD may have an average particle size wherein 80% of the alkaline MMD particles (Pso) having a particle size of between about 500 pm to about 5000 pm for example about 1000 pm to 3000 pm.

[0136] The alkaline MMD particle morphology and particle size can be measured by any conventional method, including laser diffraction, electron microscopy, dynamic light scattering, optical microscopy or size exclusion methods (such as wet or dry graduated mesh screens or filters).

[0137] The alkaline MMD comprises cathode material, anode material and carbon.

[0138] In some embodiments, the alkaline MMD comprises between about 5% w/w to about 50% w/w manganese based on the total weight of the alkaline MMD. The alkaline MMD may comprise manganese in an amount (as a % w/w based on the total weight of alkaline MMD) of at least about 5, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28,

30, 32, 34, 36, 38, 40, 42, 44, 46, 48 or 50. The alkaline MMD may comprise manganese in an amount (as a % w/w based on the total weight of alkaline MMD) of less than about 50, 48, 46, 44, 42, 40, 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8 or 5. The alkaline MMD may comprise manganese in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 10% w/w to about 40% w/w based on the total weight of alkaline MMD.

[0139] In some embodiments, the alkaline MMD comprises between about 5% w/w to about 50% w/w zinc based on the total weight of the alkaline MMD. The alkaline MMD may comprise zinc in an amount (as a % w/w based on the total weight of alkaline MMD) of at least about 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36,

38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58 or 60. The alkaline MMD may comprise zinc in an amount (as a % w/w based on the total weight of alkaline MMD) of less than about 60, 58, 54, 52, 50, 48, 46, 44, 42, 40, 38, 36, 34, 32, 30, 28, 26, 24, 22, 20, 18,

16, 14, 12, or 10. The alkaline MMD may comprise zinc in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 20% w/w to about 50% w/w based on the total weight of alkaline MMD.

[0140] In some embodiments, the alkaline MMD comprises between about 0.1% w/w to about 20% w/w carbon based on the total weight of the alkaline MMD. The alkaline MMD may comprise carbon in an amount (as a % w/w based on the total weight of alkaline MMD) of at least about 0.1, 0.2, 0.5, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18 or 20. The alkaline MMD may comprise carbon in an amount (as a % w/w based on the total weight of alkaline MMD) of less than about 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 1, 0.5, 0.2 or 0.1. The alkaline MMD may comprise carbon in an amount in a range provided by any two of these upper and/or lower amounts, for example between about 1% w/w to about 10% w/w based on the total weight of alkaline MMD.

[0141] The alkaline MMD may comprise one or more additional metal values other than manganese, carbon or zinc (e.g. impurities). If present, the type and amount of impurity in the first particle fraction may depend on the alkaline battery feed used to obtain the MMD. Typical impurities present in the mixed in alkaline MMD may include aluminium (Al), arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), potassium (K), sodium (Na) and titanium (Ti). In some embodiments, one or more additional metal values other than manganese, carbon or zinc (e.g. impurities), including one or more of those metals recited above, may be present in the alkaline MMD in an amount of less than about 100000, 10000, 5000, 4000, 3000, 2000, 1000, 800, 600, 400, 200, 100, 50, or 10 ppm based on the total weight of the alkaline MMD.

[0142] In some embodiments, the alkaline MMD is provided by the steps: al) physically separating alkaline batteries to obtain coarser particles comprising steel and/or ferrous material and finer particles comprising alkaline MMD; and a2) separating the coarser particles comprising steel and/or ferrous material from the finer particles comprising alkaline MMD.

[0143] The alkaline batteries may be physically separated using manual methods or conventional physical separation device/s such as a crusher, hammer mill or shredder. The physical separation may be performed in the presence of a liquid (e.g. wet shredding) or may be performed under dry conditions (e.g. dry- shredding).

[0144] The weight split of the finer particles comprising alkaline MMD may be between about 30% to about 80% w/w based on the total weight of the alkaline battery. The weight split of the finer particles of the alkaline MMD (in % w/w based on the total weight of the alkaline battery) may be at least about 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 or 80. The weight split of the finer particles of the alkaline MMD (in % w/w based on the total weight of the alkaline battery) may be less than about 80, 75, 70, 65, 60, 55, 50, 45, 40, 35 or 30. The weight split of the finer particles comprising alkaline MMD may be in a range provided by any two of these upper and/or lower amounts, for example between about 40% w/w to about 70% w/w based on the total weight of alkaline battery.

[0145] The weight split of the coarser particles comprising steel and/or ferrous material may be between about 10% to about 50% w/w based on the total weight of the alkaline battery. The weight split of the coarser particles comprising steel and/or ferrous material (in % w/w based on the total weight of the alkaline battery) may be at least about 10, 15, 20, 25, 30, 35, 40, 45 or 50. The weight split of the coarser particles comprising steel and/or ferrous material (in % w/w based on the total weight of the alkaline battery) may be less than about 50, 45, 40, 35, 30, 25, 20, 15 or 10. The weight split of the coarser particles comprising steel and/or ferrous material may be in a range provided by any two of these upper and/or lower amounts, for example between about 10% w/w to about 40% w/w based on the total weight of alkaline battery.

[0146] In some embodiments, step a2) further comprises screening the separated alkaline battery particles at between about 4 mm to about 6 mm to separate the coarser particles comprising steel and/or ferrous material from the finer particle of alkaline MMD, for example at about 5 mm. Alternatively, step a2) may further comprise subjecting the separated alkaline battery particles to magnetic separation to separate the coarser particles comprising steel and/or ferrous material from the finer particles comprising alkaline MMD.

[0147] In some embodiments, the physical separation of the alkaline batteries at step al) produces a dust and/or fume comprising electrolyte, wherein the dust and/or fume is optionally treated to recover the electrolyte.

[0148] In some embodiments, the separated alkaline battery particles comprising coarser particles comprising steel and/or ferrous material and finer particles comprising alkaline MMD are washed and/or attritioned prior to step a2).

[0149] In some embodiments, the separated coarser particles comprising steel and/or ferrous material is subjected to crushing to liberate and obtain alkaline MMD trapped within the coarser particles. The liberated alkaline MMD may be combined with the finer particles comprising alkaline MMD.

Fertilisers

[0150] The separated first particle fraction comprising cathode material and carbon can be used as a micronutrient in fertilisers. In one embodiment, the process further comprises mixing the separated first particle fraction comprising cathode material and carbon at step b) with a phosphorous source and optionally a binder to prepare a fertiliser.

[0151] In another aspect, the comminuted alkaline MMD particles described herein can be used as a micronutrient for fertilisers. In one embodiment, the process further comprises mixing comminuted alkaline MMD particles with a phosphorous source and optionally a binder to prepare a fertiliser. The fertiliser may be enriched in manganese and/or carbon.

[0152] The fertiliser has a manganese concentration owing to the presence of manganese from the cathode material in the first particle fraction/comminuted particles. The fertiliser may have a manganese concentration (in mg/kg of fertiliser) of between about 1000 to about 20000. The fertiliser may have a manganese concentration (in mg/kg of fertiliser) of at least about 1000, 2000, 5000, 7000, 10000, 12000, 15000, 17000 or 20000. The fertiliser may have a manganese concentration (in mg/kg based on the total weight of fertiliser) of less than about 20000, 17000, 12000, 10000, 7000,

5000, 2000 or 1000. The fertiliser may have a manganese concentration in an amount in a range provided by any two of these amounts, for example between about 1000 mg/kg to about 20000 mg/kg based on the total weight of fertiliser.

[0153] The fertiliser has a carbon concentration owing to the presence of carbon in the first particle fraction/comminuted particles.

[0154] Any suitable phosphorous source may be used to prepare the fertiliser. In some embodiments, the phosphorous source is a calcium phosphate salt or an ammonium phosphate salt, or a combination thereof. In one embodiment, the calcium phosphate salt is monocalcium phosphate (Super Phosphate). In one embodiment, the ammonium phosphate salt is monoammonium phosphate (MAP) or diammonium phosphate (DAP), or a combination thereof.

[0155] Any suitable binder may be used to bind, in one embodiment, the binder is phosphoric acid or formic acid, or a combination thereof.

[0156] The fertiliser may be prepared using conventional blending/mixing techniques known to the person skilled in the art.

[0157] In some embodiments, the amount of phosphorous source and optional binder to be mixed with the separated first particle fraction comprising cathode material and carbon or comminuted alkaline MMD particles is sufficient to provide a fertiliser with a manganese concentration of about 1 % w/w based on the total weight of the fertiliser.

[0158] In some embodiments, the amount of heavy metals (if present in the separated first particle fraction comprising cathode material and carbon comminuted alkaline MMD particles) in the final fertiliser needs to be controlled. In some embodiments, the amount of phosphorous source and optional binder to be mixed with the separated first particle fraction comprising cathode material and carbon or the comminuted alkaline MMD particles is sufficient to provide a fertiliser with a heavy metal concentration of less than 1000, 800, 600, 400, 200, 100, 50, 10, 5, or 1 ppm based on the total weight of the fertiliser. For example, in some embodiments, the fertiliser may comprise 10 ppm or less of cadmium and/or 100 ppm or less of lead.

[0159] According to some embodiments, the preferential reporting of any heavy metal present in the alkaline MMD to the flotation tail with the anode material allows for the cathode material enriched with carbon to be recovered from the flotation concentrate and readily processed into a fertiliser having low amounts of heavy metal impurity. Additionally, a more enriched manganese fertiliser can be obtained owing to reduced ppm levels of heavy metal reporting to the flotation concentrate.

[0160] In one embodiment, there is provided a fertiliser comprising comminuted alkaline MMD particles obtained from alkaline batteries, a phosphorous source, and optionally a binder. In one embodiment, there is provided a fertiliser comprising separated cathode material and carbon obtained from alkaline batteries, a phosphorous source, and optionally a binder.

Electrode materials and batteries

[0161] The separated first particle cathode material and carbon and/or anode material can be recycled for use as electrode materials for alkaline batteries. In some embodiments, the separated first particle fraction comprising cathode material and carbon and/or separated second particle fraction comprising anode material is processed into one or more electrodes for alkaline batteries.

[0162] In some embodiments, the process further comprises using the separated cathode material and carbon and/or anode material obtained by the process described herein as one or more electrodes for making an alkaline battery. In some embodiments, the process further comprises assembling an alkaline battery comprising one or more electrodes prepared using the separated first particle fraction comprising cathode material and carbon and/or separated second particle fraction comprising anode material. In one embodiment, there is provided an alkaline battery comprising one or more electrodes prepared using the separated cathode material and carbon and/or anode material obtained by the processes described herein.

[0163] In another embodiment, there is provided use of the separated first particle fraction comprising cathode material and carbon and/or anode material obtained by the processes described herein, as an electrode material (e.g. cathode and/or anode) for preparing one or more electrodes for alkaline batteries.

[0164] The present application claims priority from Australian Provisional Patent Application No. 2021902192 filed on 16 July 2021, the entire contents of which are incorporated herein by reference.

EXAMPLES

[0165] In order that the disclosure may be more clearly understood, particular embodiments of the invention are described in further detail below by reference to the following non-limiting experimental materials, methodologies and examples.

Example 1: Embodiment of process for recovering cathode material and carbon from alkaline batteries using physical separation

[0166] Referring to Figure 1, sorted end of life alkaline batteries (100) are physically separated, using a suitable device, using manual methods or conventional physical separation device/s such as a crusher, hammer mill or shredder (110). Coarser particles comprising steel and/or ferrous material (111) are recovered by simple size separation at 500 pm or magnetic separation, to recover a steel/ferrous product (200). Finer particles comprising alkaline MMD comprising cathode material and carbon (113) and anode material (112) are also generated which in some embodiments are comminuted (not shown). Optionally coarse material from the size separation stage can be recycled to the physical separation stage, for further size reduction (not shown). [0167] Table 1 shows typical mass recovered to the steel or ferrous product (200).

Table 1: Mass split of steel and/or ferrous product (200) and alkaline MMD (112) via the process described herein.

[0168] The anode material (112) and cathode material and carbon (113) are separated into separate fractions, in this example by size separation at 75 pm to create a separated second particle fraction comprising anode material (300) and a first particle fraction comprising cathode material and carbon (400).

[0169] Table 2 shows typical mass recovered and analysis of the separate anode material (300) and cathode material and carbon (400) fractions.

Table 2: Composition of material separated and recovered via the simple physical separation process described in Figure 1.

[0170] Referring to Figure 2, dust and fume (114) from physical alkaline battery separation (110), are recovered and treated (120), using conventional off gas treatment equipment such as bag filters/houses and wet gas/fume scrubbers, for example venturi or packed tower (120). Dust recovered is returned to the physical separation stage (110) and electrolyte material recovered (500) from the wet gas/fume scrubber.

Example 2: Embodiment of process for recovering values from alkaline batteries using froth flotation separation

[0171] Referring to Figure 3, end of life alkaline batteries are physically separated (120), using a suitable device, using a manual methods or a conventional physical separation device/s such as a crusher, hammer mill or shredder.

[0172] Crushed or shredded end of life alkaline batteries (121) are subject to size based classification or magnetic separation methods (130) to recover coarser particles steel or ferrous material (131) and generate a steel and/or ferrous product (200). Mass recovery to the steel and/or ferrous product is as detailed in Table 1. Optionally coarse material (133) from the size separation stage can be recycled to the physical separation stage (120), for further size reduction.

[0173] Finer particles comprising alkaline MMD, low in steel and/or ferrous material (132) undergoes froth flotation (150). In some embodiments, the alkaline MMD is comminuted prior to froth flotation separation (not shown). Anode concentrated material (151) reports preferentially to the flotation tail and is recovered as an anode material product (300). Cathode material and carbon (152) preferentially float and report to the froth fraction and is recovered as a cathode material and carbon flotation concentrate product (400).

[0174] Froth flotation can be completed with flotation reagent such as depressants, collectors and frothers using equipment (cells) specifically designed for introduction of air to promote bubble formation and recover hydrophobic particles.

[0175] Table 3 shows the impact of froth flotation (150) on the separation of cathode material and carbon (152) from anode material (151). Cathode material and carbon product (400) is recovered in the flotation concentrate from the froth flotation stage.

Table 3: Composition of material recovered via the froth flotation process described in Figure 3.

Example 3: Embodiment of process for recovering values from alkaline batteries using gravity separation

[0176] Referring to Figure 4, end of life alkaline batteries are physically separated (120), using a suitable device, using manual methods or a conventional physical separation device/s such as a crusher, hammer mill or shredder.

[0177] Crushed or shredded end of life alkaline batteries (121) are subject to size based classification or magnetic separation methods (130) to recover coarser particles comprising steel and/or ferrous material (131) and generate a steel and/or ferrous product (200). Mass recovery to the steel and/or ferrous product is as detailed in Table 1.

[0178] Finer particles comprising alkaline MMD, low in steel and/or ferrous material (132) undergoes gravity separation (160). In some embodiments, the alkaline MMD may be comminuted prior to gravity separation (not shown). Anode concentrated material (161) reports preferentially to the heavy gravity fraction and is recovered as an anode material product (300). Concentrated cathode material and carbon (162) reports preferentially to the light gravity separation fraction and is recovered as a cathode material and carbon product (400).

[0179] Gravity separation is often completed in separate stages as fine and coarse fractions and using devices such as, jigs, spirals, tables, high gravity concentrators or hydraulic / up flow classifiers.

Table 4: Composition of material separated and recovered via the gravity separation process described in Figure 4.

Example 4: Embodiment of process for recovering values from alkaline batteries using comminution and froth flotation

[0180] Referring to Figure 5, end of life alkahne batteries are physically separated (120), using a suitable device, using a manual methods or a conventional physical separation device/s such as a crusher, hammer mill or shredder.

[0181] Crushed or shredded end of life alkahne batteries (121) are subject to size based classification or magnetic separation methods (130) to recover coarser particles comprising steel and/or ferrous material (131) and generate a steel and/or ferrous product (200). Mass recovery to the steel and/or ferrous product is as detailed in Table 1. Optionally coarse material (133) from the size separation stage can be recycled to the physical separation stage (120), for further size reduction.

[0182] Finer particles comprising alkahne MMD, low in steel and/or ferrous material (132) undergoes a comminution step (140) to reduce the average particle size using devices such as grinding mill (either rod or ball) or mixing or attritioning, using an agitated tank, attritioner or high intensity agitator. Optionally additional steel and/or ferrous material can be recovered (141) from the comminution stage (140). This material can be combined into the steel and/or ferrous product (200).

[0183] Comminuted alkahne MMD particles (142) undergoes froth flotation (150). Anode concentrated material (151) report preferentially to the flotation tails fraction and is recovered as an anode material product (300). Cathode material and carbon (152) report preferentially to the froth fraction and is recovered as a cathode material and carbon flotation concentrate product (400). [0184] It is understood that froth flotation is completed with flotation agents such as depressants, collectors and frothers in using equipment (cells) specifically designed for introduction of air to promote bubble formation and recovery hydrophobic particles.

[0185] Table 5 shows the impact of grinding (140) on froth flotation (150) performance for separating cathode material and carbon (152) from anode material (151), present in the end of life alkaline batteries. Advantageously, a grind time of two minutes of the electrode material (132), leads to an improved liberation of cathode material and carbon. Further size reduction surprisingly leads to lower manganese grades in the cathode material product (400) due to disassociation of the carbon from the manganese oxide.

Table 5: Composition of material separated and recovered via the froth flotation process described in Figure 5 at varying grind times.

Example 5: Embodiment of process for recovering values from alkaline batteries using combination of froth flotation and gravity separation

[0186] Referring to Figure 6, end of life alkaline batteries are physically separated (120), using a suitable device, using a manual methods or a conventional physical separation device/s such as a crusher, hammer mill or shredder. [0187] Crushed or shredded end of life alkaline batteries (121) are subject to size based classification or magnetic separation methods (130) to recover coarser particles comprising steel and/or ferrous material (131) and generate a steel and/or ferrous product (200). Mass recovery to the steel and/or ferrous product is as detailed in Table 1. Optionally coarse material (133) from the size separation stage can be recycled to the physical separation stage (120), for further size reduction.

[0188] Finer particles comprising alkaline MMD, low in steel and/or ferrous (132) undergoes a comminution step (140) to reduce the average particle size using devices such as grinding mill (either rod or ball) or mixing or attritioning, using an agitated tank, attritioner or high intensity agitator. Optionally additional steel and/or ferrous material can be recovered (141) from the comminution stage (140). This material can be combined into the steel and/or ferrous product (200).

[0189] Comminuted alkaline MMD particles (142) undergoes froth flotation (150). Cathode material and carbon (154) floats preferentially and reports to the froth fraction and is recovered as a cathode material and carbon flotation concentrate product (400).

[0190] Anode concentrated material (153) reports preferentially to the flotation tail is recovered, and undergoes gravity separation (160). Anode concentrated material (162) report preferentially to the heavy gravity fraction and is recovered as an anode material product (300). Any cathode material and carbon recovered as a light gravity fraction (163) and is recycled to the froth flotation stage (150) for reprocessing or optionally added directly the cathode material and carbon product (400).

[0191] Table 6 shows the impact of grinding (140), froth flotation (150) and gravity separation (160) on the separation of cathode material and carbon (154) from anode material (162).

Table 6: Composition of material separated and recovered via the combine froth flotation and gravity separation process described in Figure 6.

Example 6: Embodiment of process for recovering values from alkaline batteries using combination of gravity separation and froth flotation

[0192] Figure 7 demonstrates an alternative embodiment using combination of froth flotation and gravity where end of life alkaline batteries are physically separated (120), using a suitable device, using a manual methods or a conventional physical separation device/s such as a crusher, hammer mill or shredder [0193] Crushed or shredded end of life alkaline batteries (121) are subject to size based classification or magnetic separation methods (130) to recover coarser particles comprising steel and/or ferrous material (131) and generate a steel and/or ferrous product (200). Mass recovery to the steel and/or ferrous product is as detailed in Table 1. Optionally coarse material (133) from the size separation stage can be recycled to the physical separation stage (120), for further size reduction.

[0194] Finer particles comprising alkaline MMD, low in steel and/or ferrous (132) undergoes a comminution step (140) to reduce the average particle size using devices such as grinding mill (either rod or ball) or mixing or attritioning, using an agitated tank, attritioner or high intensity agitator. Optionally additional steel and/or ferrous material can be recovered (141) from the comminution stage (140). This material can be combined into the steel and/or ferrous product (200).

[0195] Comminuted alkaline MMD particles (142) low in steel and/or ferrous material (132) undergoes gravity separation (160). Anode concentrated material (165) reports preferentially to the heavy gravity fraction and is recovered as an anode material product (300). Concentrated cathode material and carbon (162) reports preferentially to the light gravity separation fraction and is recovered as a cathode material and carbon product (400).

[0196] The light gravity separation fraction optionally undergoes froth flotation (150). Cathode material and carbon (155) floats preferentially and reports to the froth fraction and is recovered as a cathode material and carbon flotation concentrate product (400).

[0197] Anode concentrated material (156) reports preferentially to the flotation tail is recovered and is recycled to the gravity separation stage (160) for reprocessing or optionally added directly the heavy gravity fraction and is recovered as an anode material product (300).

Example 7: Use of separated cathode material and carbon as micronutrients for fertilisers

[0198] Referring to Figure 8 cathode material and carbon (400) is combined with a fertiliser (i.e. a phosphorous source) (500) and a binder (600) and blended (210). Blending can occur in a rotary drum, augmenter or other conventional mixing device. The blended product is recovered and optionally dried (213), before being used as a source of micronutrients (700) in agriculture.

Table 7: Composition of source fertiliser (500) and fertiliser product (700) after blending with cathode material (400) via the process described Figure 8.

Claims

CLAIMS:

1. A process for obtaining cathode material and carbon from alkaline mixed metal dust (MMD) obtained from alkaline batteries, comprising: a) comminuting alkaline MMD to reduce the average particle size of the alkaline MMD to liberate and obtain a first particle fraction comprising cathode material and carbon and a second particle fraction comprising anode material; and b) separating and obtaining the first particle fraction comprising cathode material and carbon from the second particle fraction comprising anode material.

2. The process of claim 1, wherein 80% of the comminuted alkaline MMD particles (Pso) have a particle size of between about 50 pm to about 500 pm.

3. The process of any one of claims 1 to 2, wherein the first particle fraction comprises manganese oxide and carbon, and the second particle fraction comprises zinc/zinc oxide.

4. The process of any one of claims 1 to 3 , wherein the first particle fraction is concentrated in manganese oxide and carbon and the second particle fraction is concentrated in zinc/zinc oxide.

5. The process of claim 3 or claim 4, wherein the first particle fraction has a higher % w/w concentration of manganese compared to the concentration of manganese in the second particle fraction, based on the total weight of the particle fraction.

6. The process of any one of claims 3 to 5 , wherein the first particle fraction comprises between about 25% w/w to about 60% w/w manganese based on the total weight of the first particle fraction.

7. The process of any one of claims 3 to 6, wherein the first particle fraction comprises between about 5% w/w to about 15% w/w carbon based on the total weight of the first particle fraction.

8. The process of any one of claims 3 to 7, wherein the second particle fraction has a higher % w/w concentration of zinc compared to the concentration of zinc in the first particle fraction, based on the total weight of the particle fraction.

9. The process of any one of claims 3 to 8 , wherein the second particle fraction comprises between about 20% w/w to about 70% w/w zinc, based on the total weight of the second particle fraction.

10. The process of any one of claims 3 to 9, wherein the carbon is physically or chemically associated with the manganese oxide as a mixed manganese oxide/carbon material. 11. The process of claim 10, wherein the mixed manganese oxide/carbon material is a mixed MnC /MmOs/carbon material.

12. The process of any one of claims 1 to 11, wherein the separating of the particle fractions at step b) comprises a size screening of the comminuted alkaline MMD particles.

13. The process of any one of claims 1 to 11, wherein the separating of the particle fractions at step b) comprises froth flotation of the comminuted alkaline MMD particles.

14. The process of claim 12, wherein the separating of the particle fractions at step b) comprises performing a froth flotation separation on the comminuted alkaline MMD particles in a froth flotation vessel, wherein the first particle fraction comprising cathode material and carbon reports to a flotation concentrate, and second particle fraction comprising anode material reports to a flotation tail, and removing the flotation concentrate from the froth flotation vessel to separate and obtain the first particle fraction comprising cathode material and carbon.

15. The process of claim 14, wherein the froth flotation separation comprises: bl) suspending the comminuted alkaline MMD particles in an aqueous solution comprising one or more froth flotation agents in the froth flotation vessel to create a slurry; t>2) aerating the slurry to generate air bubbles which float to the surface of the slurry to form a froth, wherein the first particle fraction comprising cathode material and carbon attaches to at least some of the air bubbles and floats to the top of the froth flotation vessel to report to the flotation concentrate, and the second particle fraction comprising anode material remains in the slurry to report to the flotation tail.

16. The process of claim 15 or 16, wherein the one or more froth flotation agents is selected from the group consisting of a frother, collector, and/or depressant.

17. The process of claim 15 or 16, wherein the frother is an alcohol selected from the group consisting of methyl isobutyl carbinol (MIBC), 2-ethyl hexanol, isoamyl alcohol, cyclohexanol, a-terpinol, cresol, xylenol, glycol ether, and a combination thereof.

18. The process of any one of claims 15 to 17, wherein the collector is provided in an amount of between about 100 g/t to about 8000 g/t.

19. The process of any one of claims 15 to 18, wherein the collector is a hydrocarbon oil, fatty acid or hydroximate.

20. The process of claim 19, wherein the hydrocarbon oil is kerosene. 21. The process of any one of claims 15 to 20, wherein after step bl) and prior to step t>2), the slurry comprising the comminuted alkaline MMD particles is conditioned prior to froth flotation to clean or activate the particles prior to aeration.

22. The process of any one of claims 14 to 21 , wherein the flotation tail comprising the second particle fraction is removed from the froth flotation vessel and undergoes gravity separation to recover any manganese and carbon entrained within the second particle fraction following froth flotation separation.

23. The process of claim 22, wherein the manganese and carbon recovered from gravity separation is recycled into the froth flotation vessel or combined with the flotation concentrate.

24. The process of any one of claims 14 to 23, wherein one or more heavy metals present in the comminuted alkaline MMD particles preferentially report to the flotation tail as part of the second particle fraction.

25. The process of claim 24, wherein the flotation tail has a higher ppm concentration of heavy metal compared to the concentration of heavy metal in the flotation concentrate, based on the total weight of the reported particles.

26. The process of any one of claims 1 to 25, wherein the alkaline MMD is provided by the steps: al) physically separating alkaline batteries to obtain coarser particles comprising steel and/or ferrous material and finer particles comprising alkaline MMD; and a2) separating the coarser particles comprising steel and/or ferrous material from the finer particles comprising alkaline MMD.

27. The process of claim 26, wherein the finer particles comprising alkaline MMD is between about 30% to about 80% w/w based on the total weight of the alkaline battery.

28. The process of claim 26 or claim 27, wherein step a2) comprises screening the separated alkaline battery particles at between about 4 mm to about 6 mm to separate the coarser particles comprising steel and/or ferrous material from the finer particle of alkaline MMD.

29. The process of claim 26 or claim 27, wherein step a2) comprises subjecting the separated alkaline battery particles to magnetic separation to separate the coarser particles comprising steel and/or ferrous material from the finer particles comprising alkaline MMD.

30. The process of any one of claims 26 to 29, wherein the physical separation of the alkaline batteries at step al) produces a dust and/or fume comprising electrolyte, wherein the dust and/or fume is optionally treated to recover the electrolyte. 31. The process of any one of claims 26 to 30, wherein the separated alkaline battery particles comprising coarser particles comprising steel and/or ferrous material and finer particles comprising alkaline MMD are washed and/or attritioned prior to step a2).

32. The process of any one of claims 26 to 31, wherein the separated coarser particles comprising steel and/or ferrous material is subjected to crushing to liberate and obtain alkaline MMD trapped within the coarser particles.

33. The process of any one of claims 1 to 32, wherein the separated first particle fraction comprising cathode material and carbon and/or separated second particle fraction comprising anode material is processed into one or more electrodes for alkaline batteries.

34. The process of claim 33, further comprising assembling an alkaline battery comprising one or more electrodes prepared using the separated first particle fraction comprising cathode material and carbon and/or separated second particle fraction comprising anode material.

35. The process of any one of claims 1 to 32, further comprising mixing the separated first particle fraction comprising cathode material and carbon at step b) with a phosphorous source and optionally a binder to prepare a fertiliser.

36. The process of claim 35, wherein the phosphorous source is a calcium phosphate salt or ammonium phosphate salt, or a combination thereof.

37. The process of claim 36, wherein the calcium phosphate salt is monocalcium phosphate (Super Phosphate).

38. The process of claim 36, wherein the ammonium phosphate salt is monoammonium phosphate (MAP) or diammonium phosphate (DAP), or a combination thereof.

39. The process of any one of claims 35 to 38, wherein the binder is phosphoric acid.

40. Use of the separated first particle fraction comprising cathode material and carbon obtained by the process of any one of claims 1 to 32, as a micronutrient in fertiliser.

42. A fertiliser comprising comminuted alkaline MMD particles or separated cathode material and carbon obtained from alkaline batteries, a phosphorous source, and optionally a binder.

43. An alkaline battery comprising one or more electrodes prepared using the separated cathode material and carbon and/or anode material obtained by the process of any one of claims 1 to 32.

44. Use of the separated first particle fraction comprising cathode material and carbon and/or anode material obtained by the process of any one of claims 1 to 32, as an electrode material for preparing one or more electrodes for alkaline batteries.