The present invention is directed towards a process for the recovery of lithium and other metals from spent lithiu m ion batteries or production waste containing at least one of the transition metals nickel, manganese and cobalt; the process pertains specifical ly to the separation of lithium from undesired im purities, by extracting lithiu m as lithiu m hydroxide from a particulate material obtained from the lithiu m ion batteries, particu larly the cel l ma terial thereof, typical ly after discharging, shredding and reducing at elevated temperature, and recovery of other metals such as nickel, manganese and/or cobalt from the residue af ter said extraction step in a smelting process.

Storing electrical energy is a su bject of growing interest. Efficient storage of electric energy al lows for the generation of electrical energy when it is advantageous and when and where needed. Secondary lithiu m batteries are of special interest for energy storage since they provide high energy density due to the smal l atomic weight and the large ionization energy of lithiu m, and they have become widely used as a power sou rce for many portable electronics such as cel lular phones, laptop com puters, mini-cameras, etc. but also for electric vehicles. Especial ly the growing demand for raw materials such as lithiu m, cobalt and nickel wil l cause chal lenges in future time.

Lifetime of lithium ion batteries is not u nlimited. It is to be expected, therefore, that a growing nu mber of spent lithium ion batteries wil l emerge. Since they contain im portant transition metals such as, but not limited to cobalt and nickel, and, in addition, lithium, spent lithium ion batteries may form a valuable source of raw materials for a new generation of lithiu m ion batteries. For that reason, increased research work has been performed with the goal of recycling transition metals and lithiu m from used lithiu m ion batteries, or from batteries or parts thereof that do not meet the specifications and requirements; such off-spec materials and production waste may as wel l be a source of raw materials.

Two main processes have been su bject to raw material recovery. One main process is the direct hydrometal lurgical processing of battery scrap materials. Principles have been disclosed in WO 2017/091562 and in J. Power Sou rces, 2014, 262, 255 ff. Such

hyd rometal lurgical processes wil l furnish transition metals as aqueous solutions, for example as su lfate solution, or in precipitated form, for example as hydroxides, separately or al ready in the desired stoichiometries for making a new cathode active material. I n the latter case the com position of metal salt solutions may be adjusted to the desired stoichiometries by addition of single metal components. I n WO 2017/091562, a co-precipitation of transition metals is described. I n WO 2014/180743, a process of co-precipitation is described wherein am monia or amines are used.

Typical ly, batteries are first dismantled to modules or even cel ls. I n the case of direct hy- d rometal lurgical processing the battery scrap is mechanical ly processed to separate bigger parts from casing and wiring. The electrode active materials i.e. the graphite from the anode and the lithiu m transition metal oxides from the cathode together with some impu rities form a fine powder the so cal led black mass or black powder which constitute the feed of subse quent hydrometal lu rgical process steps. I n some processes the battery scraps are subjected to a heat treatment or pyrolysis step which is performed at temperatu res wel l below the melting point of the transition metals contained in the scrap in this respect this treatment differs from a smelting process that is operated above the melting point of the transition metals contained in the scrap.

Such heat-treated black masses may be obtained from treating batteries in waste incinera tion ovens. The waste batteries or battery modu les or battery cel ls are fed to the incinera tion oven where the battery feed is partial ly bu rned. The product of this treatment is cooled and mechanical-ly treated using any kind of shredding or mil ling device suitable to separate a metal lic fraction from the powdery black mass. These black masses are materials of low reactivity u nder normal conditions and can thus be transported easily.

Several authors describe a heat treatment of waste lithiu m ion batteries or components containing the electrode active materials of these kind of batteries at elevated tem peratures above 400° C. Such a heat treatment resu lts in a com plete evaporation of the electrolyte solvents contained in the battery and in a decomposition of polymeric components. The ma terials obtained from such a heat treatment may be su bjected to different mechanical treatments and separation operations to separate out different metal fractions and a pow dery substance com prising main ly the electrode active materials from the anode, i.e. graph ite and from the cathode, i.e. a lithiu m containing transition metal material. These powders are often cal led“black masses” or“black powders” or“active masses”. Depending on the reaction conditions the latter material is often at least partial ly reduced thus, containing metal lic N i and Co phases manganese oxide phases and lithiu m salts like LiOH, Li2CO3,

Li F, UAIO2, U3PO4. The reduction takes place by reductive conditions during the heat treatment either by introducing reducing gases like hyd rogen or carbon monoxide or at tem peratures above 500° C by the carbonaceous material contained in the waste battery mate rial namely graphite and soot. J. Li et a I . , J. Hazard. Mat. 2016, 302, 97 ft, disclose an oxy- gen-free roasting/wet magnetic separation process for recycling cobalt, lithium carbonate and graphite from spent LiCo02/graphite batteries.

I n J P2012229481, waste batteries are treated in several steps in a way to bind the fluorine contained in the batteries in the conducting electrolyte salt, usual ly LiPF6, and the binder polymer, usual ly polyvinylidene fluoride (PVDF) . This is achieved by first treating the waste batteries with aqueous calciu m hyd roxide (slaked lime) solution to hydrolyze the conducting salt and precipitate fluoride as calcium fluoride. Starting from conversion experiments with model substances like LiCo0 ₂ , J P 2012-229481 discloses a process for the recovery of metals from spent lithiu m ion batteries com prising a preliminary im mersion step fol lowed by high tem peratu re oxidation, reductive roasting, aqueous treatment with filtration, and recovery of lithium carbonate from the filtrate and of transition metals from the residue.

The other main process is based u pon direct smelting of the corresponding battery scrap (e.g. EP1589121A1) . By this, a metal al loy containing N i and Co is obtained while the lithium is lost in the slag from which it is very difficu lt to recover. The metal al loy obtained can be hyd rometal lu rgical ly processed to extract the metals, e.g. the transition metals.

J P2012112027 describes the separation of lithiu m and cobalt from the melt by evaporation; it is thus assu med that such process is operated above the boiling tem peratu re of cobalt (i.e. >2870° C) .

Known methods for recovering valuable materials typical ly face the problem that spent bat teries, and namely the cel ls therein containing most of these materials, contain a high level of im purities, like compou nds of fluorine and/or phosphorous, which must be removed to recover the desired materials in a pu rity that al lows use in the production of new cel ls (bat tery grade materials) . It is therefore an objective of the present invention to provide a pro cess that al lows the easy recovery of valuable metals contained in battery scraps, namely lithiu m, nickel and if present cobalt and manganese. It is another objective of the present invention to provide a method for the recovery of fu rther elements such as carbon as graph ite, and fluoride. It is a fu rther objective of the present invention to provide an economic process reducing the nu mber of expensive and/or energy consu ming steps. It is a fu rther objective of the present invention to provide a process for the recovery of said transition metals or their com pou nds in high purity especial ly with low contents of copper and noble metals like Ag, Au and platinu m grou p metals, and high pu rity lithiu m, or a com pou nd there of, with low contents of fluorine and/or phosphorous or other metal impu rities. Typical ly, the recovered metals or metal compounds are transformed to the corresponding transition metal salts, often sulfates and lithiu m carbonate and often lithiu m hyd roxide. Known methods for binding fluoride typical ly are com plex and require several process steps. Thus, it is an objective of the present invention to solve the problems mentioned above re lated to the recovery of Ni, Co and lithiu m hydroxide from at least partial ly reduced black masses containing Ni and/or Co where at least 10% of the Ni and/or Co are present in an oxidation state lower than +2, e.g. metal lic, and which contains in addition also lithium salts. Such a black mass is often ferromagnetic.

Accordingly, the process as defined at the outset has been found, hereinafter also referred to as inventive process or as inventive recycling process. The inventive process comprises steps defined in more detail below, hereinafter also referred to as step (a) , step (b), step (c) , step (d) etc.

The invention thus primarily pertains to a process for the recovery of one or more transition metals and lithiu m as Li-salt from a material comprising waste lithiu m ion batteries or parts thereof, which process com prises the steps of

(a) providing a particulate material obtained from lithium ion batteries or parts thereof, which material contains a transition metal compound and/or transition metal selected from the grou p consisting of Ni and Co, and wherein fu rther at least a fraction of said Ni and/or Co are in an oxidation state lower than +2; which particulate material fu rther contains a lithiu m salt;

(b) treating the material provided in step (a) with a polar solvent, typical ly an aqueous solvent;

(c) separating the solids containing the one or more transition metals from the liquid, optional ly fol lowed by su bjecting said solids to a solid-solid separation for the removal of transition metals such as Ni; and

(d) treating said solids, optional ly the transition metals concentrate from the solid-solid separation, which contain the majority of the one or more transition metals, in a smelting fu rnace to obtain a metal melt containing Ni and/or Co.

The particu late material provided in step (a) is obtained from lithium containing transition metal oxide material, which material may stem from lithiu m ion batteries (battery waste), including spent batteries, waste battery material from production and off-spec material, which typical ly contains fluorine com pou nds and/or compounds of phosphorous as im pu rities, and fu rther materials containing lithiu m and said transition metals without such im pu rities, such as cathode active materials from production waste. As described below in more detail for preliminary step (i) , the material is su bjected to a reduction step prior to present step (a) to convert the transition metals Ni and/or Co into the oxidation state lower than +2 or the metal lic state, e.g. using reductive gases such as CO or hydrogen, e.g. by heating said material to a tem peratu re in the range of from 200 to 900° C in the presence of

H _2.

As noted above, the solid residue separated in step (c) may be further su bjected to a solid- solid separation for the removal of transition metals such as Ni before carrying out present step (d) ; in this case, the polar solvent used in step (b) contains an al kaline earth hydroxide.

The solid-liquid separation of step (c) may be fol lowed by said optional solid-solid separation, orthe slu rry obtained from step (b) is su bjected to a solid-solid separation and the obtained fractions are subsequently su bjected to a solid-liquid separation. The optional solid-solid separation (as described fu rther below in more detail as step dl) leads to a solid residue enriched in transition metal, especial ly nickel and/or cobalt, and a second solid residue depleted from transition metal. The present process brings about the advantage of keeping the lithium salts in a form al lowing their recovery from solution, thus providing good recovery of lithium and transition metals.

The polar solvent used in step (b) of the present process leaches lithium salt(s) from the material provided in step (a) and thus provides the desired separation of lithiu m in the liquid phase from the transition metals remaining in the solid residue. It is typical ly selected from water, alcohols, ketones, esters, organic carbonates, polyethers, nitriles, and mixtures thereof. Especial ly preferred is a polar solvent capable to dissolve an al kaline earth hydroxide such as calciu m hydroxide at least in part, for exam ple as good as water or even better. Exam ples of such solvents are polyols like glycol, glycerol or polyethylene glycols, and mixtures thereof.

To im prove the resu lt of the leaching with respect to the recovery of lithium hyd roxide, al kaline earth hyd roxides or al kaline earth oxides may be added to the slu rry; in case of al kaline earth oxides such as calciu m oxide, the polar solvent used in step (b) is

advantageously a protic solvent such as water, forming the al kaline earth hyd roxide in situ.

I n a process of special technical im portance, the leaching liquid used in step (b) for treating the particu late material (PM) provided in step (a) contains an al kaline earth hydroxide (AEH) such as calciu m hydroxide. The addition of al kaline earth hydroxide in this step brings about the advantage of binding fluoride, and other anions capable of forming lithiu m salts of low solu bility like carbonate, phosphate, alu minate, and further leads to an im proved slagging, which simplifies the separation of metal or metal al loy from the product obtained in step (d) . The invention thus preferably pertains to a process for the recovery of one or more transition metals and lithium as Li-salt from a material comprising waste lithiu m ion batteries or parts thereof, which process comprises the steps of

(a) providing a particu late material obtained waste from lithium ion batteries or parts thereof, which material contains a transition metal compound and/or transition metal selected from the group consisting of Ni and Co, and wherein fu rther at least a fraction of said Ni and/or Co are in an oxidation state lower than +2; which particulate material further contains a lithium salt;

(b) treating the material provided in step (a) with a polar solvent, which is typical ly an aqueous solvent, and an al kaline earth hyd roxide,;

(c) separating the solids containing the one or more transition metals from the liquid, optional ly fol lowed by su bjecting said solids to a solid-solid separation for the removal of transition metals such as Ni; and

(d) treating said solids containing the one or more transition metals, optional ly the transition metals concentrate from the solid-solid separation which contain the majority of the transition metals, in a smelting fu rnace to obtain a metal melt containing Ni and/or Co.

PM preferably contains nickel and optional fu rther transition metals such as Co.

Protic solvents, as specifical ly mentioned below, are mainly water, alcohols, and mixtures thereof. An aqueous mediu m such as an aqueous solvent or aqueous liquid contains primarily (i.e. by 50 % b.w. or more, especial ly 80 % b.w. or more, more especial ly 90 % b.w. or more) water, it includes water and mixtures of water with one or more alcohols; it may contain further dissolved substances as long as the major water content is maintained within one or more of the ranges given above.

Step (b) primarily provides a suspension of the particu late material in the polar solvent; it is preferably carried out with heating; the treatment with the al kaline earth hyd roxide is typical ly done at temperatu res from the range 60 to 200° C, preferably 70 to 150° C. Where the boiling point of the polar solvent is exceeded, the treatment is carried out u nder pressu re to hold the solvent, or at least a fraction thereof, in the liquid state. Of special technical importance is the temperatu re range arou nd the boiling point of water, i.e. about 70 to 150° C, where the treatment can be achieved using an aqueous liquid or water at normal pressu re or slightly elevated pressure (e.g. u p to 5 bar) . Alternatively, present step (b) can be carried out with application of higher temperatu res and pressu res, e.g. 150 to 300° C and 1.5 to 100 bar. The treatment is typical ly carried out by combining an amou nt of al kaline earth hyd roxide (AEH) with the particu late material (PM) , which corresponds to at least 5 %, and typical ly not more than 100 %, of its weight, e.g 50 - 1000 g of AEH on 1 kg of PM, preferably 100 - 1000 g AEH, more preferably 200 -1000 g AEH on 1 kg of PM. The amou nt of polar solvent is typical ly chosen to ensu re miscibility of the components, e.g. using on one part by weight of combined solids (PM and AEH) 0.5 to 95, preferably about 2.5 to 21 parts by weight of the polar solvent; or in certain cases 1 to 20, e.g. about 2 to 10 parts by weight of the polar solvent.

I n one embodiment of the present invention, step (b) is carried out in a vessel that is pro tected against strong bases, for exam ple molybdenu m and copper rich steel al loys, nickel- based al loys, duplex stainless steel or glass-lined or enamel or titaniu m coated steel. Fur ther ex-amples are polymer liners and polymer vessels from base-resistant polymers, for example poly-ethylene such as H DPE and U H M PE, fluorinated polyethylene, perfluoroal- koxy al kanes (“PFA”) , polytetrafluoroethylene (“PTFE”) , PVd F and FEP. FEP stands for fluorinated ethylene propylene polymer, a copolymer from tetrafluoroethylene and hex- afluoropropylene.

The treatment is typical ly done using a mixing device, e.g. a stirrer, with power application typical ly up tp 10 W per kg of suspension, e.g. 0.5 to 10 W/kg, and/or cycled by pum ping in order to achieve a good mixing and to avoid settling of insolu ble com ponents. Shearing can be fu rther improved by employing baffles. Furthermore, the slu rry obtained in step (b) may advantageously be su bjected to a grinding treatment, for exam ple in a bal l mil l or stirred bal l mil l; such grinding treatment may lead to a better access of the polar solvent to a particu late lithiu m containing transition metal oxide material. Shearing and mil ling devices applied typical ly are sufficiently corrosion resistant; they may be produced from similar materials and coatings as described above for the vessel.

I n one embodiment of the present invention, step (b) has a duration in the range of from 20 minutes to 24 hou rs, preferably 1 to 10 hou rs.

I n one embodiment step (b) is performed at least twice to reach an optimu m recovery of lithium hyd roxide or the lithiu m salt. Between each treatment a solid-liquid separation is performed. The obtained lithiu m salt solutions may be com bined or treated separately to recover the solid lithium salts.

I n on em bodiment of the present invention, step (b) and (c) are performed in batch mode. I n on em bodiment of the present invention, step (b) and (c) are performed in continuous mode, e,g. in a cascade of stirred vessels (step b) and/or in a cascade of stirred vessel plus centrifuge (step c).

I n one em bodiment of the present invention, the polar solvent in present step (b) is an aqueous mediu m, and the ratio of the aqueous mediu m to material provided in step (a) is in the range of from 1 : 1 to 99 : 1, preferably 5 : 1 to 20 : 1 by weight.

The al kaline earth hyd roxide is general ly selected from hydroxides of Mg, Ca, Sr and Ba; preferred are calcium hydroxide, barium hydroxide and mixtures thereof; most preferred is calcium hyd roxide. The al kaline earth hyd roxide used in present step (b) may be used as such, or may be added in form of the oxide, or mixtu re of oxide and hydroxide, to form the al kaline earth hydroxide u pon contact with a polar solvent selected from protic solvents noted above.

The particulate material provided in step (a) general ly com prises material obtained from lithiu m contai ning transition metal oxide material such as lithium ion battery waste after carrying out the preliminary step (i) of heating u nder inert or reducing conditions to a temperatu re from the range 80 to 900° C, e.g. 200 to 850° C, especial ly 200 to 800° C. Preliminary step (i) is typical ly carried out directly after discharging the lithiu m ion batteries, dismantling and/or shredding as explained in more detail below. I n some applications sh redding and/or dismantling is carried out after preliminary step (i). The lithium ion batteries used, and thus the particu late material provided in step (a) , typical ly contains carbon, e.g. in the form of graphite.

Where elevated temperatures are noted, e.g. for treating the material in present step (i), exposu re times, where indicated, define the total dwel l time in the reactor or furnace, which has been heated to said elevated temperatu re; the tem perature of the material shou ld reach a temperatu re from the range given for at least a fraction of said dwel l time.

U n less specified otherwise, "contain" in relation to any substance general ly means presence of such su bstance in an amou nt typical ly stil l detectable by x-ray powder diffraction, e.g. 1 % by weight or more, or means presence of such constituents in an amou nt typical ly detectable by ICP after a suitable digestion, e.g. 10 ppm by weight or more. The particu late material provided in present step (a) typical ly contains, with respect to the elements, about 1 to 10 % of lithiu m, about 3 to 30 % of the combined transition metal elements cobalt and/or nickel, and about 4 to 40 % of transition metal elements in total including any cobalt, nickel, manganese, copper and iron (al l percentages by weight of d ry particu late material provided in step (a)) .

I n the fol lowing, the particu late material provided in step (a) , as wel l as the material su bjected to step (i), wil l alternatively be su mmarized as lithiu m containing transition metal oxide material.

The carbon content may be used in the reducing pre-treatment described above as a reducing agent. Other reducing agents usefu l to provide a reducing gas stream for this preliminary step (i) are as described in J P2012229481; preferred is hyd rogen and/or carbon monoxide. The invention thus includes a process com prising steps (i) and (a) , (b) and (c) and (d) as described above, wherein the heating step (i) is conducted under reducing conditions com prising the presence of carbon and/or a reducing gas selected from hyd rogen, methane and carbon monoxide.

Step (i) Method 1:

Where hydrogen is used as the reducing gas, preliminary step (i) is preferably carried out as fol lows: (i) heating the lithiu m containing transition metal oxide material to a temperatu re from the range 200 to 900° C, or as indicated above, in the presence of H ₂ .

Typical ly, the lithium containing transition metal oxide material heated in step (i) stems from lithiu m ion batteries and may contain fluorine, typical ly in the range from 1% to 8% by weight, and/or phosphorous in the range from 0.2% to 2% by weight, relative to the weight of the lithium containing transition metal oxide material.

Step (i) carried out with hyd rogen includes heating the lithiu m containing transition metal oxide material to a tem perature in the range of from 200 to 900° C, preferably 300 to 600° C, more preferably 350 to 500° C. Since strong heating, especial ly under oxidative conditions, but to a lesser extent also u nder reductive atmosphere, tends to increase for mation of insolu ble species (such as LiM n0 ₂ ) , it is preferred to general ly expose the lithium containing transition metal oxide material not to tem peratu res of 500° C or more. Conse quently, it is preferred to keep the tem peratu re in step (i) below 500° C; in one em bodiment of the present process, step (i) is carried out using hydrogen and a temperatu re from the range 350 to 450° C, e.g. 380 to 450° C, especial ly 380 to 440° C. The atmosphere used to do the reduction, according to this embodiment, contains 0.1% to 100% by volu me of hyd ro gen, the rest being a non-oxidizing gas, preferably nitrogen, argon, steam, carbon monoxide, carbon dioxide or mixtures of at least two of these gases. Preferred non-oxidizing gases are nitrogen and steam and mixtu res of nitrogen and steam. I n a preferred embodiment, step (i) of present process is carried out mainly u nder hyd rogen, for exam ple u nder an atmosphere containing 35 to 100%, preferably 50 to 100%, by volu me (normal conditions) of hydrogen, the rest, if present, being a non-oxidizing gas. I n said embodiment of the present invention, step (i) has a duration (dwel l time) in the range of from 10 minutes to 30 hou rs, preferably 20 min to 8 hou rs, more preferably 30 min to 4 hou rs. Of special tech nical interest is a du ra tion of step (i) lasting 20 to 90 minutes, with presence of hyd rogen as preferred.

The concentration of hyd rogen in the reduction atmosphere and the reaction time are de pendent on each other. Usual ly a low concentration of hyd rogen requires longer reduction times and vice versa.

I n a preferred process of the invention, step (i) is thus carried out by heating the lithium containing transition metal oxide material to a tem peratu re in the range of from 350 to 450° C in the presence of more than 35 %, especial ly 50-100%, by volu me of H ₂ , and for a time period of 20 to 90 minutes. Within present invention, a particu larly preferred process conducts step (i) using a temperature between 400 and 450° C, e.g. between 400 and 420° C, for u p to 2.5 hours and 35 or more volu me-% of hydrogen to recover Li in step (b) in an especial ly efficient way; applying too high temperatures may resu lt in lower yields, longer duration does not lead to a negative effect but tends to lower the space time yield, while H ₂ concentrations >35 vol-% translate into short reaction times £2.5 h and are therefore fa vored; an optimum space time yield is achievable using more than 80 vol.-% of hyd rogen.

After the heat treatment the material is transferred from the oven to a cooling u nit. Here the material is cooled down to temperatures preferably of 100° C and below. The cooling can be done at am bient conditions e.g. by storing the hot material in a chamber or vessel or in a rotating tube which may be the final non-heated or cooled part of a rotary kil n where the heat treatment is performed such that the heat can be conducted to the environment. Pref erably the hot material can be cooled and conveyed by cooled conveying screws. A faster cooling can be obtained by introducing gases which after having passed the hot material bed may be fed to a heat exchanger. Such cooling by gases can be designed as fixed, mov ing or fluidized bed. The gases used are preferably inert gases like nitrogen, argon or carbon dioxide. It is also possible to em ploy reducing gases used for the reduction preferably during the beginning of the cooling period when the material is stil l at a tem peratu re close to oven temperatu re. Afterwards the gas composition may be changed to an inert gas at lower tem peratures even oxygen containing gases like air or mixtu res of air and inert gases may be employed.

Alternatively, to cooling under dry conditions in a gas atmosphere it is also possible to quench the hot material by a liquid. This can be done by spraying the cooling liquid to the hot material either in quantities that the liquid is evaporated and the material remains virtu- al ly dry (cooling by evaporation) or in bigger quantities that a slu rry of the material is formed. Cooling by a liquid is especial ly preferred when the obtained cooled material or slu rry can be employed directly in step (b) of this invention. Thus, the preferred quenching liquids are polar solvents that are sufficiently tem peratu re stable most preferred is water. The liquid can be pu mped to a heat exchanger and recycled back to the cooling vessel.

Step (i) Method 2:

Where a carbonic material such as carbon is used as the reducing agent, preliminary step (i) is preferably carried out as fol lows: (i) heating the lithium containing transition metal oxide material to a tem peratu re in the range of from 200 to 900° C in the presence of said carbonic material such as carbon; e.g. in the presence of graphite. I n a preferred embodi ment of the present invention the graphite contained in the black mass is used as reducing agent.

Typical ly, the lithium containing transition metal oxide material heated in step (i) stems from lithium ion batteries and may contain typical im pu rities such as fluorine, as explained below in more detail.

Step (i) carried out with carbonic material such as carbon as reducing agent includes heat ing the lithium containing transition metal oxide material to a temperature in the range of from 200 to 900° C, preferably 300 to 850° C, more preferably 500 to 850° C.

The atmosphere used to effect the reduction, according to this embodiment, contains either no oxygen, or u p to 20% by volu me of oxygen, the rest being a non-oxidizing gas, preferably nitrogen, argon, steam, carbon monoxide, carbon dioxide or mixtu res of at least two of these gases. Preferred non-oxidizing gases are nitrogen and carbon monoxide and mixtu res of nitrogen and carbon monoxide. I n a preferred embodiment, step (i) of the present process is carried out u nder air or under diluted air, for exam ple u nder an atmosphere containing 1 to 20%, preferably 1 to 10%, by volu me (normal conditions) of oxygen, the rest, if present, be ing a non-oxidizing gas. I n said em bodiment of the present invention, step (i) has a duration in the range of from 10 minutes to 30 hou rs, preferably 20 min to 8 hou rs, more preferably 30 min to 4 hou rs. Of special tech nical interest is a du ration of step (i) lasting 20 to 120 minutes, especial ly 30-120 minutes, with presence of carbon as preferred.

After the heat treatment the material is transferred from the oven to a cooling u nit. Here the material is cooled down to temperatures preferably of 100° C and below. The cooling can be done at am bient conditions e.g. by storing the hot material in a chamber or vessel or in a rotating tube which may be the final non-heated or cooled part of a rotary kil n where the heat treatment is performed such that the heat can be conducted to the environment. Pref- erably the hot material can be cooled and conveyed by cooled conveying screws. A faster cooling can be obtained by introducing gases which after having passed the hot material bed may be fed to a heat exchanger. Such cooling by gases can be designed as fixed, mov ing or fluidized bed. The gases used are preferably inert gases like nitrogen, argon or carbon dioxide. It is also possible to em ploy reducing gases used for the reduction preferably during the beginning of the cooling period when the material is stil l at a tem peratu re close to oven temperatu re. Afterwards the gas com position may be changed to an inert gas at lower tem peratures even oxygen containing gases like air or mixtures of air and inert gases may be employed.

Alternatively, to cooling under dry conditions in a gas atmosphere it is also possible to quench the hot material by a liquid. This can be done by spraying the cooling liquid to the hot material either in quantities that the liquid is evaporated and the material remains virtu al ly dry (cooling by evaporation) or in bigger quantities that a slu rry of the material is formed. Cooling by a liquid is especial ly preferred when the obtained cooled material or slu rry can be employed directly in step (b) of this invention. Thus, the preferred quenching liquids are polar solvents that are sufficiently tem peratu re stable most preferred is water. The liquid can be pu mped to a heat exchanger and recycled back to the cooling vessel.

I n one em bodiment of the present invention the reduction conditions related to the hyd ro gen and/or carbon/oxygen concentration, and the temperatu re and duration of step (i) are chosen that at least a part of the lithium containing transition metal oxide material contains para-, anti-ferro-, ferro- and/or ferrimagnetic com ponents. Preferred is the formation of ferro- or ferrimagnetic components resu lting from the at least partial reduction of the lithi u m containing transition metal material. The extend of the reduction may vary in the range between 1 to 100% with respect to the nickel contained in the lithiu m containing transition metal material; preferred is a range from 80 to 100%.

The particu late material provided in present step (a) thus contains a transition metal com pou nd and/or transition metal, wherein the transition metal is selected from the group con sisting of M n, Ni and/or Co, and wherein fu rther at least a fraction of said Ni and/or Co, if present, are in an oxidation state lower than +2, and at least a fraction of said M n, if pre sent, is manganese(l l)oxide; nickel and/or cobalt therein are typical ly at least in part pre sent in their metal lic state.

Presence of phases such as Ni and/or Co in oxidation state lower than +2, M n in the form of manganese(l l)oxide; and nickel and/or cobalt as metal, are detectable by XRD as de scribed fu rther below. The lithiu m salt present in the particulate material provided in present step (a) are detected by standard methods as described below. The lithium salt contained in the particu late ma terial provided in step (a) typical ly com prise one or more salts of LiOH, Li F, Li2O, Li2CO3, LiHCO3, lithiu m alu minates, lithium phosphate salts, mixed oxides of Li and one or more of Ni, Co, M n, Fe, Al, Cu and/or fluorides of Ni, Co, M n, Fe, Al, Cu.

LiOFI, Li F, Li2O, Li2CO3, LiHCO3, lithiu m alu minates and lithium phosphates typical ly make u p 95% b.w. or more of al l lithiu m salts present. Very often contained are Li F, Li2CO3, LiOFI and lithium alu minate in cases where the particu late material provided in step (a) stems from lithiu m ion batteries or parts thereof. A larger fraction of fluoride if present, e.g. 50 % b.w. or more of said fluoride, is typical ly present as lithiu m fluoride. Since fluoride salt pre sent typical ly stems in part from the former battery electrolyte salt and the polymeric bind er, which set free hyd rogen fluoride du ring preliminary steps of discharging or dismantling or drying of the battery materials, other species of fluoride salts resulting from the rapid reaction of the hyd rogen fluoride with former cel l or electrode materials, such as cobalt fluoride, may be present as wel l.

The particu late material provided in present step (a) general ly is a battery material contain ing lithiu m and one or more transition metals including nickel and/or cobalt, e.g. a material that stems from lithium ion batteries or parts of lithium ion batteries, especial ly the cel l ma terials thereof. It is provided for present step (a) in the form of a d ry powder, wet powder or suspension of particles in a liquid. The material typical ly has an average particle diameter (D50 according to ISO 13320 EN:2009-10) from the range 1 pm to about 2 m m, especial ly 1 pm to 1 m m. I n a typical process, the u pper limit of the size of particles in the powdery ma terial is given by a sieving step performed before present step (a) or even before step (i) , e.g. using a sieve whose mesh al lows passing of particles of 2 mm at maximu m, especial ly of 1 m m at maximum.

Typical ly, said lithiu m containing transition metal oxide material is obtained after mechanic removal of casing, wiring or circuitry, thus typical ly consisting mainly of the cel l material.

For safety reasons, such lithiu m ion batteries are discharged com pletely, e.g. by im mersion in a d ry conductive bath such as metal shreds, or at least 80% discharged electrical ly (pref erably more than 90%, most preferably more than 95%) by which the residual electrical en ergy may be recovered, otherwise, shortcuts may occur that constitute fire and explosion hazards. Such lithiu m ion batteries may be disassembled, pu nched, mil led, for exam ple in a ham mer mil l, or sh redded, for exam ple in an industrial sh redder. Although not preferred, it is also possible to discharge the batteries by immersion into a conducting liquid e.g. an aque ous solution of a metal salt like sodiu m su lfate or the like. It is also possible to perform the sh redding in a liquid preferably water. This has the advantage of preventing dust formation and the occu rrence of ignitable atmospheres.

It may be advantageous to at least partial ly remove electrolytes before subjecting the mate rial to the preliminary step (i) , especial ly electrolytes that comprise an organic solvent or a mixtu re of organic solvents, for exam ple by d rying, for exam ple at temperatures in the range of from 50 to 250° C u nder atmospheric pressu re or below. As noted above, the lithium containing transition metal oxide material is preferably not exposed to higher tem peratu res (especial ly not to 400° C or more) under oxidizing conditions before su bjecting it to present step (a) .

Stil l, in one em bodiment of the present invention, prior to the reduction step (i) a heat treatment under oxidative conditions may be performed. This treatment may be done in a range of tem peratures between 250 to 900° C, preferably between 350 and 800° C, e.g. 300 to 400° C. To achieve oxidative conditions, air or an oxygen containing gas may be intro duced to the reactor. The oxidative treatment may be carried out in the presence of al kaline earth hyd roxides or oxides. The reaction can also be carried out in the presence of water as steam thus applying hydrothermal conditions.

I n one embodiment of the present invention, said lithium containing transition metal oxide material is from battery scraps. I n a preferred embodiment of the present invention, said lithiu m containing transition metal oxide material is from mechanical ly treated battery scraps, for exam ple from battery scraps treated in a ham mer mil l or in an industrial sh red der. This mechanical treatment can be done u nder d ry conditions or u nder wet conditions preferably in the presence of water.

I n one embodiment of the present invention, prior to step (a) a step (al) is performed, said step (al) com prising the removal of e.g. carbon or organic polymers by a solid-solid separa tion method. Exam ples of such solid-solid separation methods are electro-sorting, sieving, magnetic separation, flotation, or other classification methods. The solid-solid separation can be performed dry or in the presence of a suitable dispersing mediu m, preferably water.

I n one embodiment of the present invention the mechanically treated battery scrap is grou nd prior to step (a) . Such grinding is preferably performed in bal l mil ls or stirred bal l mil ls. The mil ling can be performed under wet or d ry conditions, preferred are d ry condi tions. I n one embodiment of the present invention, the mechanical ly treated battery scrap is con tacted with water and/or organic solvent fol lowed by a solid-liquid separation step prior to step (a) .

I n one embodiment the mechanical ly treated battery scrap is contacted with a basic or acid ic solution to facilitate the detachment of active material from the electrode foils, this is described in WO2018192122.

I n one embodiment of the present invention, the mechanical ly treated battery scrap is su b jected to a solvent treatment prior to the thermal treatment of step (i) in order to dissolve and separate polymeric binders used to bind the lithiu m transition metal oxides to the cur rent col lector fil ms. Suitable solvents are N-methyl pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N-ethyl pyrrolidone, dimethylsu lfoxide, hexamethyl phoshor- amide, tetramethylu rea, trimethyl phosphate and triethyl phosphate in their pu re form or as mixtures.

The solvent treatments described above can be performed with one or more solvents in consecutive steps or in one step employing a solvent that is capable to dissolve electrolyte com ponents and the binder polymers. The solvents are applied in a tem peratu re range from 10° C to 200° C. Especial ly the dissolution of polymers may require elevated tem peratu res in the range from 50 to 200° C preferably between 100 and 150° C. The upper temperatu re is usual ly limited by the boiling point of the solvent u nless pressures higher than 1 bar are applied.

I n one em bodiment the washing of mechanical ly treated battery scrap is performed with non-protic solvents in the absence of hu midity, e.g., under dry gases like d ry air, d ry nitro gen.

I n a typical embodiment of the present invention, said lithiu m containing transition metal oxide material com prises battery scrap material, parts or materials from parts of a lithium ion battery, off-spec material including pure electrode material, or mixtu res of such materi als. However, said lithium containing transition metal oxide material preferably contains in the range of from 0.1 to 80% by weight of compou nds other than nickel com pounds such as nickel/cobalt com ponents or nickel/cobalt/manganese or nickel/cobalt/alu minum com pounds, if applicable, and in extreme cases the valuable material is a minority component. Examples of such com ponents are carbon in electrical ly conductive form, hereinafter also referred to as conductive carbon, for exam ple graphite, soot, and graphene. Further exam ples of im pu rities are copper and its com pou nds, aluminu m and compounds of alu minu m, for example alumina, iron and iron compounds, zinc and zinc compounds, silicon and silicon compounds, for example silica and oxidized silicon SiO _y with zero < y £ 2, tin, silicon-tin alloys, and organic polymers such as polyethylene, polypropylene, and fluorinated polymers, for example polyvinylidene fluoride, tetrafluoroethylene polymers and the like. Further impu rities are fluorine compounds, e.g inorganic fluorides, and compounds of phosphorous that may stem from liquid electrolytes, for example in the widely employed LiPF ₆ and products stemming from the hydrolysis of LiPF ₆ . Battery scraps that serve as starting material for the inventive process may stem from multiple sources, and therefore said lithium containing transition metal oxide material in most of the embodiments contains compounds other than nickel/cobalt compounds or nickel/cobalt/manganese or nickel/cobalt/aluminum compo nents, if applicable, one of such components being carbon in electrically conductive form in the range of from 2 to 65 % by weight, referring to entire lithium containing transition metal oxide material.

In a typical embodiment of the present invention, said lithium containing transition metal oxide material contains one or more of the following further components or impurities: i) in the range of from 20 ppm to 10 %, especially 20 ppm to 3 %, by weight of copper, as metal or in form of one or more of its compounds; ii) in the range of from 100 ppm to 15 % by weight of aluminum, as metal or in form of one or more of its compounds; iii) in the range of from 100 ppm to 5 % by weight of iron, as metal or alloy or in form of one or more of its compounds; iv) in the range of from 20 ppm to 2 % by weight of zinc, as metal or alloy or in form of one or more of its compounds; v) in the range of from 20 ppm to 2 % by weight of zirconium, as metal or alloy or in form of one or more of its compounds; vi) in the range of from 1% to 8%, especially 2% to 8%, by weight of fluorine, calculated as a sum of organic fluorine, e.g., bound in polymers, and inorganic fluoride in one or more of its inorganic fluorides; vii) in the range of from 0.2% to 2% by weight of phosphorus, which may occur in one or more inorganic compounds; viii) in the range of from 100 ppm to 15 % by weight of manganese, as metal or in form of one or more of its compounds.

Examples of such embodiments are lithium containing transition metal oxide material con taining one or two of the above additional components, or additional components (i), (ii) and (iii); (i), (ii) and (iv); (i), (ii) and (v); (i), (ii) and (vi); (i), (ii) and (viii); (i), (iii) and (iv); (i), (iii) and (v); (i), (iii) and (vi); (i), (iii) and (vii); (i), (iii) and (viii); (i), (iv) and (v); (i), (iv) and (vi);

(i), (iv) and (vii); (i), (iv) and (viii); (i), (v) and (vi); (i), (v) and (vii); (i), (v) and (viii); (i), (vi) and (vii); (i), (vi) and (viii); (i), (vii) and (viii); (i), (ii), (iii) and (iv); (i), (ii), (iii) and (v); (i), (ii),

(iii) and (vi); (i), (ii), (iii) and (vii); (i), (ii), (iii) and (viii); (i), (ii), (iv) and (v); (i), (ii), (iv) and

(vi); (i), (ii), (iv) and (vii); (i), (ii), (iv) and (viii); (i), (ii), (v) and (vi); (i), (ii), (v) and (vii); (i),

(ii), (v) and (viii); (i), (ii), (vi) and (vii); (i), (ii), (vi) and (viii); (i), (ii), (vii) and (viii); (i), (iii),

(iv) and (v); (i), (iii), (iv) and (vi); (i), (iii), (iv) and (vii); (i), (iii), (iv) and (viii); (i), (iii), (v) and

(vi); (i), (iii), (v) and (vii); (i), (iii), (v) and (viii); (i), (iii), (vi) and (vii); (i), (iii), (vi) and (viii);

(i), (iii), (vii) and (viii); (i), (iv), (v) and (vi); (i), (iv), (v) and (vii); (i), (iv), (v) and (viii); (i), (iv), (vi) and (vii); (i), (iv), (vi) and (viii); (i), (iv), (vii) and (viii); (i), (v), (vi) and (vii); (i), (v), (vi) and (viii); (i), (v), (vii) and (viii); (i), (vi), (vii) and (viii); (ii), (iii), (iv) and (v); (ii), (iii), (iv) and

(vi); (ii), (iii), (iv) and (vii); (ii), (iii), (iv) and (viii); (ii), (iii), (v) and (vi); (ii), (iii), (v) and (vii);

(ii), (iii), (v) and (viii); (ii), (iii), (vi) and (vii); (ii), (iii), (vi) and (viii); (ii), (iii), (vii) and (viii);

(ii), (iv), (v) and (vi); (ii), (iv), (v) and (vii); (ii), (iv), (v) and (viii); (ii), (iv), (vi) and (vii); (ii),

(iv), (vi) and (viii); (ii), (iv), (vii) and (viii); (ii), (v), (vi) and (vii); (ii), (v), (vi) and (viii); (ii), (v),

(vii) and (viii); (ii), (vi), (vii) and (viii); (iii), (iv), (v) and (vi); (iii), (iv), (v) and (vii); (iii), (iv),

(v) and (viii); (iii), (iv), (vi) and (vii); (iii), (iv), (vi) and (viii); (iii), (iv), (vii) and (viii); (iii), (v),

(vi) and (vii); (iii), (v), (vi) and (viii); (iii), (v), (vii) and (viii); (iii), (vi), (vii) and (viii); (iv), (v),

(vi) and (vii); (iv), (v), (vi) and (viii); (iv), (v), (vii) and (viii); (iv), (vi), (vii) and (viii); (v), (vi),

(vii) and (viii); (i), (ii), (iii), (iv) and (v); (i), (ii), (iii), (iv) and (vi); (i), (ii), (iii), (iv) and (vii); (i),

(ii), (iii), (iv) and (viii); (i), (ii), (iii), (v) and (vi); (i), (ii), (iii), (v) and (vii); (i), (ii), (iii), (v) and (viii); (i), (ii), (iii), (vi) and (vii); (i), (ii), (iii), (vi) and (viii); (i), (ii), (iii), (vii) and (viii); (i), (ii), (iv), (v) and (vi); (i), (ii), (iv), (v) and (vii); (i), (ii), (iv), (v) and (viii); (i), (ii), (iv), (vi) and (vii); (i), (ii), (iv), (vi) and (viii); (i), (ii), (iv), (vii) and (viii); (i), (ii), (v), (vi) and (vii); (i), (ii), (v), (vi) and (viii); (i), (ii), (v), (vii) and (viii); (i), (ii), (vi), (vii) and (viii); (i), (iii), (iv), (v) and (vi); (i),

(iii), (iv), (v) and (vii); (i), (iii), (iv), (v) and (viii); (i), (iii), (iv), (vi) and (vii); (i), (iii), (iv), (vi) and (viii); (i), (iii), (iv), (vii) and (viii); (i), (iii), (v), (vi) and (vii); (i), (iii), (v), (vi) and (viii); (i),

(iii), (vi), (vii) and (viii); (i), (iv), (v), (vi) and (vii); (i), (iv), (v), (vi) and (viii); (i), (iv), (v), (vii) and (viii); (i), (iv), (vi), (vii) and (viii); (i), (v), (vi), (vii) and (viii); (ii), (iii), (iv), (v) and (vi); (ii),

(iii), (iv), (v) and (vii); (ii), (iii), (iv), (v) and (viii); (ii), (iii), (iv), (vi) and (vii); (ii), (iii), (iv), (vi) and (viii); (ii), (iii), (iv), (vii) and (viii); (ii), (iii), (v), (vi) and (vii); (ii), (iii), (v), (vi) and (viii); (ii), (iii), (v), (vii) and (viii); (ii), (iii), (vi), (vii) and (viii); (ii), (iv), (v), (vi) and (vii); (ii), (iv), (v), (vi) and (viii); (ii), (iv), (v), (vii) and (viii); (ii), (iv), (vi), (vii) and (viii); (ii), (v), (vi), (vii) and (viii); (iii), (iv), (v), (vi) and (vii); (iii), (iv), (v), (vi) and (viii); (iii), (iv), (v), (vii) and (viii); (iii), (iv), (vi), (vii) and (viii); (iii), (v), (vi), (vii) and (viii); (iv), (v), (vi), (vii) and (viii); (i), (ii), (iii),

(iv), (v) and (vi); (i), (ii), (iii), (iv), (v) and (vii); (i), (ii), (iii), (iv), (v) and (viii); (i), (ii), (iii), (iv), (vi) and (vii); (i), (ii), (iii), (iv), (vi) and (viii); (i), (ii), (iii), (iv), (vii) and (viii); (i), (ii), (iii), (v),

(vi) and (vii); (i), (ii), (iii), (v), (vi) and (viii); (i), (ii), (iii), (v), (vii) and (viii); (i), (ii), (iii), (vi),

(vii) and (viii); (i), (ii), (iv), (v), (vi) and (vii); (i), (ii), (iv), (v), (vi) and (viii); (i), (ii), (iv), (v),

(vii) and (viii); (i), (ii), (iv), (vi), (vii) and (viii); (i), (ii), (v), (vi), (vii) and (viii); (i), (iii), (iv), (v),

(vi) and (vii); (i), (iii), (iv), (v), (vi) and (viii); (i), (iii), (iv), (v), (vii) and (viii); (i), (iii), (iv), (vi),

(vii) and (viii); (i), (iii), (v), (vi), (vii) and (viii); (i), (iv), (v), (vi), (vii) and (viii); (ii), (iii), (iv),

(v), (vi) and (vii); (ii), (iii), (iv), (v), (vi) and (viii); (ii), (iii), (iv), (v), (vii) and (viii); (ii), (iii), (iv),

(vi), (vii) and (viii); (ii), (iii), (v), (vi), (vii) and (viii); (ii), (iv), (v), (vi), (vii) and (viii); (iii), (iv), (v), (vi), (vii) and (viii); (i), (ii), (iii), (iv), (v), (vi) and (vii); (i), (ii), (iii), (iv), (v), (vi) and (viii); (i), (ii), (iii), (iv), (v), (vii) and (viii); (i), (ii), (iii), (iv), (vi), (vii) and (viii); (i), (ii), (iii), (v), (vi),

(vii) and (viii); (i), (ii), (iv), (v), (vi), (vii) and (viii); (i), (iii), (iv), (v), (vi), (vii) and (viii); (ii),

(iii), (iv), (v), (vi), (vii) and (viii). Another example is a lithium containing transition metal oxide material containing each of the above additional components.

Each of the percentages given above are by weight of the dry material (i.e. lithium contain ing transition metal oxide material as provided in present step (a)).

In an embodiment of specific technical interest, the particulate material provided in step (a) contains only low amounts of calcium or no calcium at all. Such particulate material con taining a transition metal compound and/or transition metal further contains a lithium salt and a fluoride salt; it may optionally contain calcium provided that the element ratio calcium to fluorine is 1.7 or less or is zero.

Said lithium containing transition metal oxide material typically contains nickel or cobalt or both nickel and cobalt. Examples of lithium containing transition metal oxide materials may be based on lithiated nickel cobalt manganese oxide (“NCM”) or on lithiated nickel cobalt aluminum oxide (“NCA”) or mixtures thereof.

Examples of layered nickel-cobalt-manganese oxides are compounds of the general formula Li _1+x (Ni _a Co _b Mn _c M ¹ _d ) _1-x 0 ₂ , with M ¹ being selected from Mg, Ca, Ba, Al, Ti, Zr, Zn, Mo, V and Fe, the further variables being defined as follows: zero £ x £ 0.2 0.1 £ a £ 0.95,

Zero £ b £ 0.9, preferably 0.05 < b £ 0.5, zero £ c £ 0.6, zero £ d £ 0.1, and a + b + c + d = l.

I n a preferred em bodiment, in compounds according to general formula (I)

M ¹ is selected from Ca, Mg, Zr, Al, Ti and Ba, and the fu rther variables are defined as above.

Exam ples of lithiated nickel-cobalt aluminu m oxides are com pou nds of the general formu la

Typical values for r, h, i and j are:

h is in the range of from 0.8 to 0.95,

i is in the range of from 0.02 to 0.3,

j is in the range of from 0.01 to 0.10, and

r is in the range of from zero to 0.4.

Particularly preferred are

each with x as defined above, and

Said lithiu m containing transition metal oxide material may have a regu lar shape but usual ly it has an irregu lar shape. It is preferred, though, to remove a light fraction such as housing parts from organic plastics and aluminum foil or copper foil as far as possible, for exam ple in a forced stream of gas.

I n one em bodiment the composition of the atmosphere is changed du ring step (i) this may be done for example in the case that volatile organic com pou nds are present in the feed that wil l be stripped off at an inert atmosphere before switching the atmosphere to a reduc ing one, e.g. hyd rogen containing one. I n one embodiment an oxidizing atmosphere in a temperature range between 20 to 300° C is em ployed in step (i) prior to the reduction with a hyd rogen containing atmosphere. By this em bodiment, some im purity com ponents namely organic components may be bu rned off, or the material is dried (especial ly employing temperatures u p to 250° C as noted further above. Preferred oxidizing gases are oxygen or oxygen containing gases e.g. air. The materi al stem ming from spent lithium ion battery cel ls, containing lithiu m, transition metal oxide and typical ly a fluorine and/or phosphorous compound, is preferably not subjected to oxidi zation above 300° C before carrying out the steps of the present process.

I n one em bodiment of the present invention, prior to step (a) a step (al) is performed, said step (al) comprising the removal of e.g. carbon or organic polymers by a d ry solid-solid separation method. Exam ples of such dry solid-solid separation methods are electro sorting, sieving, magnetic separation or other classification methods. Here step (al) is in troduced as an additional step.

I n one em bodiment of the present invention, the material provided in step (a) is grou nd prior to step (b) in order to de-agglomerate different solid particles from one another in cases that these are somehow agglomerated, for example by residual binder polymers. The grind ing can be performed u nder dry or wet conditions. Preferably the grinding is done in an aqueous mediu m that is also employed in the consecutive step (b) .

At the end of step (b) , the pressu re may be released if applicable. A solution of a lithium salt is obtai ned as the liquid from step (c) , typical ly an aqueous solution containing LiOH.

Prior to present step (c) , the solid residue is contained in polar solvent, which may be an aqueous solution, forming a suspension. I n the case that the extraction of the Li- com pou nd(s) is done in two or more steps as described above the solid residue wil l be con tained in the slu rry of the second or last step, respectively.

The solid residue obtained in step (c) is recovered by the solid-liquid separation step (c) . This can be a filtration or centrifugation or a kind of sedimentation and decantation, option al ly with su bsequent washing steps applying the respective polar solvent used in step (b) as washing mediu m. The filtrate and washing liquids are usual ly com bined prior to further work u p targeting the respective lithium salts. I n order to recover such solid material containing fine particles, for exam ple with an average diameter of 50 pm or less, floccu lants may be added, for example polyacrylates. The solid residue obtained according to step (c) is characterized by a typical elemental com position which resu lts from applying the preferred process conditions during step (b) . Specifical ly, the solid residue is characterized by having a composition typical for battery scrap material (Li, graphite and at least one of Ni and Co; M n may be present, too) but a significantly higher (Ni + Co + M n) to Li weight ratio. Since battery scrap material, especial ly the cathode active material, is characterized by a (Ni + Co + M n) : Li weight ratio be tween 5 and 12, the solid residue after step (c) is characterized by its lower Li content and therefore by a (N i + Co + M n) : Li weight ratio between 13 and 100000. Fu rthermore, the preferred process in step (b) is accom panied by a significantly increased calciu m content, which is very low in the original particulate material provided in step (a) as mentioned above (0-0.5 wt.-%) . The solid residue obtained according to a preferred variant of present step (c) is characterized by an elemental Ca weight content between 2 and 50 % (relative to the d ry solid) .

This solid residue obtainable according to step (c) is a valuable sou rce of materials useful for the production of new batteries; steps for the isolation of such materials are described hereinbelow.

The solid residue obtained according to step (c) may subsequently be su bjected to a step (d l) inter alia adjusting the amou nt of carbon contained in the residue. This can be achieved by a solid-solid separation or by a heat treatment that burns off the carbon in an oxygen containing gas e.g. air. Such bu rning process may be integrated in the smelting pro cess of step (d) employing an oven with different heating zones and tem peratu re regimes; examples are shaft fu rnaces, where the material enters the oven in a pre-heating zone at temperatu res between 500 to 900° C u nder conditions where at least part of the carbona ceous material is burned.

Where step (dl) of the present invention comprises a solid-solid separation step, this may be a wet solid-solid separation step. This solid-solid separation step serves to separate non-solu ble components like carbon and polymers or insolu ble inorganic components like metal oxide particles from the metal lic or metal oxide com ponents of the lithium containing transition metal oxide material. After said solid-solid separation of step (dl) , a solid con centrate fraction is obtained containing the majority of the Ni and/or Co in enriched form. Such solid-solid separation step may be performed by mechanical, colu mn or pneu matic, or hybrid flotations. I n many em bodiments, col lector compou nds are added to the slurry which render the target com ponents hyd rophobic. Typical col lector compou nds for carbon and polymer particles are hydrocarbons or fatty alcohols which are introduced in amounts of 1 g to 50 kg/t of the solid residue obtained from step (c) . It is also possible to perform the flota- tion in an inverse sense i.e. transforming the original ly hydrophilic components into strongly hyd rophobic com ponents by special col lector su bstances, e.g., fatty alcohol su lfates or es- terquats. Preferred is the direct flotation em ploying hyd rocarbon col lectors for exam ple mineral oils, kerosene or Diesel. I n order to im prove the selectivity of the flotation towards carbon and polymer particles su ppressing agents can be added that reduce the amou nts of entrained metal lic and metal oxide components in the froth phase. Agents that can be used may be acids or bases for control ling the pH value in a range of from 3 to 9. It may also be ionic com ponents that adsorb on the metal lic or metal oxide su rface e.g. sodium silicate or bipolar components like, for exam ple, amino acids. I n order to increase the efficiency of the flotation it may be advantageous to add carrier particles that form agglomerates with the hydrophobic target particles, e.g., polymer particles, carbonaceous particles, for exam ple graphite or coal. By using magnetic carrier particles magnetic agglomerates may be formed that can be separated magnetical ly. I n the case that the target com ponents are paramag netic, antiferro-, ferri- or ferromagnetic it is also possible to separate these com ponents by a magnetic separation employing high intensity magnetic separators (“WH I MS”) , mediu m intensity magnetic separators (“M I MS”) or low intensity magnetic separators (“LI MS”) . Oth er solid-solid separation techniques make use of the density difference of the solid constit uents for example the density difference between graphite and metals or metal oxides. These techniques comprise float-sin k methods employing fluids of densities intermediate to the densities of the solid com ponents that wil l be separated. Another tech nique of this sort is the heavy media separation. Further separation tech niques based on density differences are spirals and hydrocyclones.

Also combinations of at least two of the afore mentioned solid-solid separation techniques may be employed. These com binations may com prise rougher, scavenger and cleaner steps which are typical for mineral processing flow sheets. Also, a combination of a solid-solid separation with a carbon bu rning step can be conceived.

I n one preferred em bodiment the solid-solid separation in step (dl) is a magnetic separa tion.

I n one embodiment of the present invention the solid material obtained from step (c) is grou nd prior to step (dl) in order to liberate the different solid particles from one another in cases that these are somehow agglomerated for exam ple by residual binder polymers. Such grinding is preferably performed in bal l mil ls or stirred bal l mil ls.

I n one em bodiment of the present invention, step (dl) is a wet solid-solid separation em ploying an aqueous mediu m preferably water as fluid. The ratio of the fluid mediu m to solid material in such step (dl) is typical ly in the range of from 1 : 1 to 99 : 1, preferably 2 : 1 to 9 : 1 by weight.

From the wet solid-solid separation of step (dl) , two slu rries resu lt: one containing the tar get transition metal containing solid material and one that contains the other components like carbonaceous materials and polymers and if applicable also some inorganic com pounds. By suitable selection and, if necessary, com bination of solid-solid separation steps, at least 60% of the Ni and/or Co is obtained and concentrated in one fraction. Preferably at least 80 to 99% of the Ni and/or Co is separated. The carbon content in the metal contain ing fraction is significantly reduced but is typical ly not less than 5 % b.w., e.g. 5 to 20 % b.w.

The solid material recovered in step (c) or (d l) is a particu late material that may contain residual liquids e.g. water. I n one em bodiment of the present invention this material wil l be d ried to a residual content of liquids below 5 %, preferably below 1 % b.w. before being in troduced into step (d) . I n another em bodiment the solid residue obtained in step (c) wil l be agglomerated to spherical or cylindrical particles with a diameter in the range of 1 to 20 m m, preferably 2 to 8 m m. To produce such pel lets that are sufficiently mechanical ly stable to being introduced into a smelting oven in step (d) the agglomeration of the particu late material is accomplished by the addition of binders. Such binders are preferably inorganic binders like for exam ple bentonite or gam ma-alu mina or mixtu res of at least two of these materials. Also, organic polymeric binders can be applied based on starch, cel lulose, molas ses, lignin, polyacrylate, waxes or mixtu res of at least two of these materials. Also, mixtu res of inorganic and organic binders are suitable. I n addition to these binders, slag forming ad ditives like quartz alumina and/or limestone may be added al ready to the agglomerates. The agglomerates can be formed by extrusion or pel letizing in drum or disc pel letizers as known in the art, the latter two are preferred. The amou nts of slag forming additives and their ratio are selected in a way as to al low a suitable slag formation. The slag com position can be modeled with commercial software e.g. FactSage ^® . Usual ly the pel letization is performed in the presence of water after the pel lets have been formed these are d ried and calcined to obtain hardened sintered bodies of sufficient mechanical stability.

The solid residue from step (c) or step (dl) preferably after pel letization, d rying and calcin ing are fed to a smelter fu rnace. Typical ly, the feed material is pre-mixed with slag forming additives and fluxes (e.g. soda, potash, lime, borax). Suitable smelter fu rnaces are bath smelting furnaces, top blown rotary converters, shaft fu rnaces, electric arc fu rnaces, plasma fu rnaces and others. The temperature in the fu rnace at the tapping points is typical ly be tween 1200 and 1600° C. The fu rnace can be operated in continuous or batch mode. The solid residue from step (c) or (d l) may be also mixed with nickel or cobalt concentrates obtained from ores preferably from laterite especial ly saprolite ores and co-fed to the smelting unit.

The tapped al loy is typical ly fed to an u nderwater atomizer, granu lator or casting mou ld (continuous or batch) . The slag is typical ly fed to a slag cooling pool or to an underwater granu lating device or is sprayed by a strong stream of gas to smal l d roplets that are cooling down on their trajectory to the grou nd.

The fu rnace may be operated in a way that the carbonaceous material contained in the sol id residue obtained from step (c) or (dl) is burned and providing energy for the smelting and reducing conditions. I n cases where the carbonaceous material provided by the solid residue is not sufficient, additional carbu rant e.g. heavy mineral oil can be fed into the oven. The operation of such fu rnaces is wel l known in the art of pyrometal lu rgy. Alternatively, the concentration levels of carbonaceous materials may be limited, e.g. to provide selective re duction of the target transition metals without over reducing the melt and pu l ling deleteri ous components into the al loy.

The al loy thus obtained from the smelting (d) contains the metals nickel and/or cobalt; typi cal ly, it may fu rther contain copper, iron and also some manganese. Ignoble metals like aluminu m are al most com pletely separated into the slag. Fluorine compou nds are also trapped in the slag or separated into the flue gas from which fluorides can be recovered by suitable scru bbers and filters.

The al loy material obtained may be fu rther subjected to a hydrometal lu rgical processing (step (f) to separate nickel and cobalt from copper). Separated nickel and cobalt, and man ganese if present, can be transformed into metal salts which can be used in the production of battery materials or other applications.

I n one embodiment of the present invention, the liquid phase of the slu rry fed to step (d l) stil l contains dissolved lithium. I n this case one or the other or both slu rries obtained from the solid-solid separation in step (dl) are advantageously su bjected to a solid-liquid sepa ration in order to recover the lithiu m solution. The lithiu m solution then may be further treated in step (e).

I n step (e), the solution obtained from any of the foregoing steps, e.g. step (c) and/or step (dl) , which contains lithiu m, may be treated to recover the lithiu m as hydroxide or salts in form of solid materials. I n one embodiment of the present invention the Li-salts, especial ly LiOH, are recovered by evaporation of the water contained in the solution (el) . I n order to produce the desired Li- salt of high pu rity, this evaporation may be carried out in two or more consecutive steps (e.g. e2 and e3) .

Firstly, the Li containing solution from any of the foregoing steps is concentrated close to the point where the solubility limit of LiOH is reached. This step is accompanied by a solid formation (e.g. crystal lization) of impurities having lower solu bilities than LiOH; potential im pu rities can be but are not limited to Ca(OH)2, CaF2, CaCO3, Li F. These are separated by a solid-liquid separation, e.g. by filtration or centrifugation or a kind of sedimentation and decantation. Since the remaining amount of solids to be separated is smal l, preferably depth filters are applied. Also, a com bination of two solid-liquid separation steps is possi ble, for exam ple a hyd rocyclone fol lowed by a depth filter. For the case that Li F is precipi tated du ring this first concentration step (e2) , it is preferred to re-feed the solid material to step (b) .

Secondly, the filtrate obtained from solid-liquid separation after one of the concentration steps, i.e. the concentrated LiOH solution, is used in the next evaporation step (e3). LiOH of high quality can be obtained by evaporating the remaining water and a solid formation of LiOH. I n case of crystal lization, the crystals are separated from the remaining mother liquor, again, by solid liquid separation and are optional ly washed. To concentrate the im pu rities, several crystal lization steps fol lowed by washing and solid-liquid separation are possible. Any mother liquors obtained from crystal lization can be su bjected to fu rther evaporation and crystal lization and/or to a recycling by introducing the mother liquor into step (b) or (el) , (e2) or (e3) .

For al l the above-mentioned solidification steps subsequent d rying of the solids is advanta geous. Drying either below 60° C or at higher temperatures u nder high humidity conditions leads to LiOH monohydrate; otherwise, at least partial ly water free LiOH is obtained.

For the case, the filtrate obtained after step (c) is d ried by total evaporation of the polar solvent, e.g. water, according to described step (el) , a LiOH (an hydride or monohyd rate) is obtained which is of high pu rity (>98.5%) . It contains an im-purity spectru m which is char acteristic for the above described process, e.g. carbon-based im pu rities of less than 0.35 wt.-%.

Referring to a LiOH monohydrate the characteristic impu rities are calcium, fluorine and so diu m. Their typical amou nts within this LiOH monohyd rate are: Ca: 100 ppm - 1.29 wt.-%

F: 0.1 - 1.29 wt.-%

Na: 0.1 - 1.29 wt.-%

Fu rthermore, it is possible, depending on the composition of the PM , that significant amounts of zinc, aluminu m, potassiu m and chlorine are present. I n these cases, their char acteristic amou nts in an above described LiOH monohyd rate which is obtained after step (el) are in the fol lowing ranges:

Zn: 20 ppm - 1.29 wt.-%

Al: 50 ppm - 1.29 wt.-%

K: 0.1 - 1.29 wt.-%

Cl : 0.1 - 1.29 wt.-%

Depending on the d rying conditions, anhyd rous LiOH instead of the monohyd rate is ob tained. I n this case, the above-mentioned characteristic amounts of im pu rities, which are related to the monohyd rate, are higher concentrated, respectively, by a factor of 1.75 (cor responds to the molar weight of the monohyd rate divided by the molar weight of the an hy- d rate) for 100% water free LiOH.

Al l steps applied including steps (b) , (c) , (dl) and (e) are preferably carried out in inert at mosphere, e.g. nitrogen, argon, or in CO2 free air.

I n one em bodiment of the present invention, Li is recovered from the solution obtained in step (c) by precipitation as Li-carbonate by the addition of sodium carbonate or am monium carbonate, or by carbonic acid formed by the dissolution of carbon dioxide, preferably under pressu re (step e5).

I n one em bodiment this Li-carbonate is dissolved again by fu rther adding CO2 into solution, pref-erably under pressu re, forming dissolved LiHCO3 (e6). I m pu rities which may be pre sent can be separated using state-of-the-art pu rification techniques, e.g. solvent extraction, precipitation and/or ion exchange. After this optional purification, Li-carbonate can be ob tained by raising the temperature of the solution which directly leads to Li-carbonate pre cipitation (e7) . Pu re Li-carbonate can be obtained by su bsequent solid-liquid separation.

I n a preferred embodiment of the present invention, Li is recovered as LiOH.

The obtained solid Li-salts and/or LiOH may be further purified by dissolution and recrys tal lization as known in the art. The al loy containing Ni and/or Co obtained from step (d) may be subjected to a su bsequent step (f) al lowing the extraction of Ni and, if applicable of Co, and - if applicable - other val uable metals such as copper. For the extraction, acidic or am monia leaching may be ap plied.

I n the cou rse of such step (f) , the transition metal material may be treated with a leaching agent, which is preferably an acid selected from su lfuric acid, hydroch loric acid, nitric acid, methanesu lfonic acid, oxalic acid and citric acid or a combination of at least two of the foregoing, for exam ple a com bination of nitric acid and hyd rochloric acid. I n another pre ferred form the leaching agent is an inorganic acid such as sulfu ric acid, hyd roch loric acid, nitric acid,

an organic acid such as methanesu lfonic acid, oxalic acid, citric acid, aspartic acid, malic acid, ascorbic acid, or glycine,

a base, such as am monia, aqueous solutions of amines, am monia, ammoniu m car bonate or a mixtu re of ammonia and carbon dioxide, or

a chelating agent, such as Na4EDTA, Na2H2EDTA, H4EDTA (in the fol lowing sections these three chelating agents are su mmarized writing just EDTA) or dimethylglyoxime.

I n one form, the leaching agent com prises an aqueous acid, such as an inorganic or organic aqueous acid. I n another form the leaching agent com prises a base, preferable ammonia or an amine. I n another form the leaching agent comprises a complex former, preferably a che lating agent. I n another form the leaching agent comprises an inorganic acid, an organic acid, a base or a chelating agent.

The concentration of leaching agents may be varied in a wide range, for example of 0.1 to 98% by weight and preferably in a range between 10 and 80%. Preferred example of aque ous acids is aqueous sulfuric acid, for exam ple with a concentration in the range of from 10 to 98% by weight. Preferably, aqueous acid has a pH value in the range of from -1 to 2. The amou nt of acid is adjusted to maintain an excess of acid referring to the transition metal. Preferably, at the end of step (f) the pH value of the resu lting solution is in the range of from -0.5 to 2.5. Preferred examples of a base as leaching agents are aqueous am monia with a molar N H3 to metal (Ni, Co) ratio of 1:1 to 6:1, preferably 2:1 to 4:1, preferably also in the presence of carbonate or su lfate ions. Suitable chelating agents like EDTA or dimethyl glyoxime are often applied in a molar ratio of 1:1 to 3:1. The leaching may be carried out in the presence of oxidizing agents. A preferred oxidizing agent is oxygen as pure gas or in mixtu res with inert gases e.g. nitrogen or as air. Other oxi dizing agents are oxidizing acids, e.g. nitric acid, or peroxides like hyd rogen peroxide.

I n one embodiment of the present invention such step (f) can be performed by dissolving the solid Ni-concentrate obtained in step (c) or (d) in an acid selected from su lfu ric acid, hyd rochloric acid, nitric acid, methane sulfonic acid, oxalic acid and citric acid.

I n one embodiment of the present invention such step (f) may be performed by treating the solid Ni-concentrate obtained in step (c) or (d) with an aqueous solution of ammoniu m car bonate or ammoniu m bicarbonate. Such aqueous solution may contain additional am monia.

I n one em bodiment of the present invention the Ni-concentrate obtained from step (c) or (d) is treated in step (f) with an acid selected from sulfu ric acid, hydroch loric acid, nitric acid, methanesu lfonic acid, oxalic acid and citric acid or a com bination of at least two of the foregoing, for example a com bination of nitric acid and hyd roch loric acid. I n the case of aqueous acids the concentration of acid may be varied in a wide range, for example of 0.1 to 99% by weight preferably in a range between 10 and 96%. The amount of acid is adjusted to maintain an excess of acid. Preferably, at the end of step (f) the pH value of the resu lting solution is in the range of from -0.5 to 2.

Preferred exam ple of aqueous acids is aqueous sulfu ric acid, for exam ple with a concentra tion in the range of from 10 to 98% by weight.

The treatment in accordance with step (f) may be performed at a temperatu re in the range of from 20 to 200° C, especial ly 20 to 130° C. If temperatures above 100° C are desired, step (f) is carried out at a pressure above 1 bar. Otherwise, normal pressu re is preferred.

I n one em bodiment of the present invention, step (f) is carried out in a vessel that is pro tected against strong acids, for example molybdenu m and copper rich steel al loys, nickel- based al loys, du plex stain less steel or glass-lined or enamel or titanium coated steel. Fu r ther examples are polymer liners and polymer vessels from acid-resistant polymers, for ex ample polyethylene such as H DPE and U H M PE, fluorinated polyethylene, perfluoroal koxy al kanes (“PFA”) , polytetrafluoroethylene (“PTFE") , PVDF and FEP. FEP stands for fluorinat ed ethylene propylene polymer, a copolymer from tetrafluoroethylene and hexafluoropropyl- ene The slurry obtained from step (f) may be stirred, agitated, or su bjected to a grinding treat ment, for example in a bal l mil l or stirred bal l mil l. Such grinding treatment leads often to a better access of water or acid to a particulate transition metal material.

I n one embodiment of the present invention, step (f) has a duration in the range of from 10 minutes to 10 hours, preferably 1 to 3 hours. For exam ple, the reaction mixtu re in step (f) is stirred at powers of at least 0.1 W/l or cycled by pum ping in order to achieve a good mixing and to avoid settling of insoluble com ponents. Shearing can be further improved by employ ing baffles. Al l these shearing devices need to be applied sufficiently corrosion resistant and may be produced from similar materials and coatings as described for the vessel itself.

Step (f) may be performed u nder an atmosphere of air or u nder air diluted with N ₂ . It is pre ferred, though, to perform step (f) u nder inert atmosphere, for exam ple nitrogen or a rare gas such as Ar.

The treatment in accordance with step (f) leads to a dissolution of the metal com pounds that remain after the leaching of the LiOH in step (b), including im pu rities other than carbon and organic polymers. I n most embodiments, a slurry is obtained after carrying out step (f) . Residual lithium and transition metals such as, but not limited to nickel, cobalt, copper and, if applicable, manganese, are often in dissolved form in the leach, e.g. in the form of their salts.

I n embodiments wherein a so-cal led oxidizing acid has been used in step (f) it is preferred to add reducing agent in order to remove non-used oxidant. Examples of oxidizing acids are nitric acid and combinations of nitric acid with hyd roch loric acid. I n the context of the pre sent invention, hyd rochloric acid, su lfuric acid and methanesu lfonic acid are preferred ex amples of non-oxidizing acids.

I n one em bodiment step (f) is performed u nder inert gas like nitrogen or argon.

Depending on the concentration and amount of the aqueous acid used in step (f) , the liquid phase obtained in step (f) may have a transition metal concentration in the range of from 1 u p to 25 % by weight, preferably 6 to 15% by weight. The transition metal concentration de pends on the solubility of the corresponding salts of the acid employed. Preferably, step (f) is performed such that the transition metal concentrations of the main metals such as Ni and, optional ly, Co and M n are slightly below the solubility limit of the least solu ble salt in order to ensu re a high metal concentration in the solution. Having dissolved the Ni-concentrate in step (f) in a consecutive step (fl), the pH value of the above slu rry or solution may be adjusted to 2.5 to 8, preferably 5.5 to 7.5 and even more preferably from 6 to 7. The pH value may be determined by conventional means, for exam ple potentiometrical ly, and refers to the pH value of the continuous liquid phase at 20° C. The adjustment of the pH value is done by dilution with water or by addition of bases or by a com bination thereof. Exam ples of suitable bases are ammonia and al kali metal hyd rox ides, for example LiOH, NaOH or KOH, in solid form, for exam ple as pel lets, or preferably as aqueous solutions. Com binations of at least two of the foregoing are feasible as wel l, for example combinations of am monia and aqueous caustic soda.

Preferably, an optional step (f2) com prises the removal of precipitates of carbonates, ox ides, phosphates, hydroxides or oxyhyd roxides of residual Al, Cu, Fe, Zr, Zn, or combinations of at least two of the foregoing formed in the optional step (fl) . Said precipitates may form during adjustment of the pH value. Phosphates may be stoichiometric or basic phosphates. Without wishing to be bound by any theory, phosphates may be generated on the occasion of phosphate formation through hyd rolysis of hexafluorophosphate or its decom position products formed du ring pretreatment of the particu late material provided in present step (a) . It is possible to remove said precipitates by filtration or with the hel p of a centrifuge or by sedimentation. Preferred filters are belt filters, filter press, suction filters, and cross-flow filter. Filtering aids and/or floccu lants may be added to improve the solid-liquid separation.

I n a preferred em bodiment of the present invention, step (f2) includes an optional step (f3) . Step (f3) includes a treatment of a solution obtained after step (fl) or step (f2) with metal lic nickel, metal l ic cobalt or metal lic manganese or any com bination of at least two of the fore going.

I n optional step (f3) , a solution obtained after step (f2) is contacted with metallic nickel, cobalt or manganese or a combination of at least two of the foregoing, for exam ple in a col u mn. I n such embodiments, it is advantageous to provide a colu m n packed with metal lic nickel, metal lic cobalt or metal lic manganese or a com bination of at least two of the forego ing in the form of lu mps or granu les, for exam ple as fixed bed, and al lowing a stream of the solution to flow through such colu mn.

I n one embodiment of the present invention, step (f3) is performed at normal pressu re.

I n one em bodiment of the present invention, step (f3) has a duration in the range of from 30 minutes to 5 hou rs. I n case step (f3) is performed in a colu mn, the du ration corresponds to the average residence time. I n one embodiment of the present invention, step (f3) is performed at a pH value range from 1 to 6, preferably pH 2 to 5. The lower the pH value in step (f3) the higher is the amou nt of metal selected from Ni, Co and M n to be dissolved u nder hydrogen formation.

Step (f3) is particu larly useful for removal of copper traces. By performing step (f3) , no new im purities that wou ld require an additional purification step are introduced into the solution of transition metals. Even if said metal lic nickel, cobalt or manganese contains traces of copper they do not dissolve.

The copper separation in step (f3) may also be performed by electrolysis preferably employ ing an electrochemical filter cel l employing conductive particu late material as electrode e.g. the graphite contained in the black mass.

Alternatively, copper may be extracted by solvent extraction or ion-exchange prior to the precipitation of Al, Fe, Zr and/or Zn, and may be recovered as high grade copper by elec trowi nning.

From the mixed Ni, Co and/or M n containing solution, the individual metals may be recov ered as pure metal salts according to known procedu res in the art e.g. precipitation as ox ides, hydroxides, carbonates or su lfides, solvent extraction, ion exchange, electrowin ning. These pu re metal salts may be re-introduced to the synthesis of cathode active materials e.g. according to the fol lowing steps (gl) and (g) .

An optional step (g) , typical ly performed subsequent to step (f) and optional steps (fl) , (f 2) , (f3) , includes the precipitation of the transition metals as mixed hydroxides or mixed car bonates, preferably as mixed hydroxides.

I n a preferred em bodiment of the present invention, step (g) is performed by adding ammo nia or an organic amine such as dimethyl amine or diethyl amine, preferably am monia, and at least one inorganic base such as lithiu m hydroxide, sodiu m hyd roxide, potassium hydrox ide, sodiu m carbonate, sodiu m bicarbonate, potassiu m carbonate or potassium bicarbonate or a combination of at least two of the foregoing. Preferred is the addition of ammonia and sodium hyd roxide.

I n one em bodiment of the present invention, step (g) is performed at a tem peratu re in the range of from 10 to 85° C, preferred are 20 to 50° C. I n one em bodiment of the present invention, the concentration of organic amine - or am monia - is in the range of from 0.05 to 1 mole/l, preferably 0.1 to 0.7 mole/l. The term“am monia concentration” in this context includes the concentration of ammonia and ammoniu m. Particular preference is given to amou nts of ammonia for which the solu bility of Ni ²⁺ and Co ²⁺ in the mother liquor is not more than 1000 ppm each, more preferably not more than 500 ppm each.

I n one em bodiment of the present invention, mixing is affected during step (g) of the in ventive process, for example with a stirrer, a rotor stator mixer or a bal l mil l. Preference is given to introducing a stirrer output of at least 1 W/l into the reaction mixtu re, preferably at least 3 W/l and more preferably at least 5 W/l. I n one embodiment of the present invention, a stirrer output of not more than 25 W/l can be introduced into the reaction mixtu re.

The optional step (g) of the inventive process may be performed in the presence or absence of one or more reducing agents. Exam ples of suitable reducing agents are hydrazine, prima ry alcohols such as, but not limited to methanol or ethanol, fu rthermore ascorbic acid, glu cose and al kali metal su lfites. It is preferred to not use any reducing agent in step (g) . The use of a reducing agent or inert atmosphere or both in com bination is preferred in cases where major amounts of manganese are present in the transition metal oxide material, for exam ple, at least 3 mol-%, referring to the transition metal part of the respective cathode active material.

Step (g) of the inventive process may be performed u nder an atmosphere of an inert gas like e.g. nitrogen or argon or carbon dioxide.

I n one embodiment of the present invention, step (g) is performed at a pH value in the range of from 9 to 13.5, preferred are pH values from 11 to 12.5 in the case of hydroxides and pH values in the range from 7.5 to 8.5 in the case of carbonates. The pH value refers to the pH value in the mother liquor, determined at 23° C.

Step (g) may be carried out in a batch reactor or - preferably - continuously, for example in a continuous stirred tan k reactor or in a cascade of two or more, for example two or th ree continuous stirred tan k reactors.

Step (g) of the inventive process may be performed u nder air, u nder inert gas atmosphere, for exam ple under noble gas or nitrogen atmosphere, or under reducing atmosphere. An example of a reducing gas is, for example, S0 ₂ . Preference is given to working u nder inert gas atmosphere, especial ly under nitrogen gas. For the pu rpose of further pu rification, the solids recovered in step (g) may be separated off and dissolved in an acid, for example hydroch loric acid or more preferably su lfu ric acid.

By performing the inventive process, it is possible to recover the transition metals nickel and/or cobalt and, if applicable, other metals from cathode materials containing nickel and/or cobalt, in a form that they can be converted into cathode active materials very easily. I n particu lar, the inventive process al lows the recovery of transition metals such as nickel and, optional ly, cobalt and/or manganese, that contain on ly tolerable traces of impurities such as copper, iron, and zinc, for exam ple with less than 10 ppm of copper, preferably even less, for example 1 to 5 ppm.

I n one em bodiment of the present invention, in an additional step (gl) prior to step (g) , nickel, cobalt and/or manganese salts are added to the recycled metal salt solution from step (f) or (fl) , (f2) or (f3) to adjust the metal ratio to the composition of a desired mixed metal hyd roxide precipitate, which may be employed as precu rsor material for the produc tion of cathode active material. Du ring such precipitation, additional metal salts may be added, preferably as an aqueous solution of anions of acids em ployed in step (f) ; an exam ples of such a metal is alu minu m which may be added as aluminum su lfate. The mixed metal hyd roxide precipitate may be separated from the liquid by solid-liquid separation and d ried to obtain a d ry mixed metal hydroxide precipitate with a water content of not more than 10 wt%. By this, a cathode active material precu rsor can be obtained directly in the consecutive precipitation step (g) .

I n one embodiment of the present invention, the solid al loy containing Ni and/or Co ob tained in step (d) is treated, preferably after atomization, with am monium (bi)carbonate in aqueous solution in concentrations of 0.2 to 30 wt%, preferably 1 to 20 % by weight. The slu rry may be heated to temperatu res of 30 to 150° C. At tem peratu res above the boiling point of the mixtu re the heating is performed under pressu re. Below the boiling point the application of pressu re is advantageous to maintain sufficient ammonia and carbon dioxide in the system.

The treatment with am moniu m (bi)carbonate may be performed u nder inert atmosphere or in the presence of oxygen for example under air. The leachate or solution may also contain additional ammonia and/or hyd rogen peroxide.

By the ammonium (bi)carbonate treatment Ni and/or Co and, if applicable, Cu, wil l be dis solved as ammonium com plexes. The concentration of the metal am monium com plexes in the leaching liquor may be in the range of 0.2 to 30 wt% by metal preferably 1-15 wt%. The solution obtained by this treatment is su bjected to a solid-liquid separation resu lting in a solution containing main ly the Ni and if applicable Co and Cu ammoniu m com plexes and a separated solid residue containing main ly other transition metals if applicable namely M n and Fe.

The solution obtained can be heated and ammonia can be stripped off by pu rging with car bon dioxide. By this first Ni-carbonate and upon longer treatment advantageously at in creased temperatu re also Co-carbonate wil l be obtained as precipitates. This al lows the separation of both metals. I n one em bodiment of the present invention Ni and Co carbonate are not separated from each other. The precipitated mixed Ni/Co carbonates are separated from the mother liquor and can be dissolved by su lfu ric acid or other acids to obtain a solu tion of the corresponding Ni and if applicable Co salts. This solution may also contain smal l amou nts of Cu-salts that may be removed by a treatment with metal lic Ni, Co or M n as de scribed above. Other impurities like Fe or Al that may be contained in low concentrations may be removed by hydroxide or carbonate precipitation at pH-values between 2.5 to 8 as described above as wel l.

From the purified Ni- and/or Co-salt solution, Ni- and Co-hydroxides may be co

precipitated.

I n one embodiment of the present invention the solution is fu rther treated to extract Ni and Co-salts separately for example by solvent extraction methods. From the separated N i and Co salts pu re metals can be recovered via electrochemical methods known in the art.

I n one embodiment the precipitation of the transition metals after steps (f1) , (f2) and (f3) is done by hydrogen under elevated pressu re. For this the pH-value of the solution is kept basic by addition of am monia and/or am monium carbonate. By this Ni, Co and Cu can be precipitated as metals. Certain catalysts known in the art may be added to improve this re action.

Description of methods:

Particle size distribution measu rements, including determination of D50, are performed ac cording to ISO 13320 EN:2009-10.

Elemental analysis of lithiu m, calciu m and manganese (performed inter alia for determining the Li, Ca, M n content of the particulate material provided in present step (a)) :

Reagents are: Deionized water, hydrochloric acid (36%), K2CO3-Na2CO3 mixture (dry), Na2B4O7 (dry), hydrochloric acid 50 vol.-% (1:1 mixture of deionized water and hydrochloric acid (36%)); all reagents are p.a. grade.

Sample preparation:

0.2-0.25 g of the particulate material for present step (a) (typically obtained from waste lith ium ion batteries after performing the preliminary reduction step (i)) is weighed into a Pt crucible and a K2CO3-Na2CO3/Na2B4O7 fusion digestion is applied: The sample is burned in an unshielded flame and subsequently completely ashed in a muffle furnace at 600° C. The remaining ash is mixed with K2CO3-Na2CO3/Na2B4O7 (0.8 g/0.2 g) and melted until a clear melt is obtained. The cooled melting cake is dissolved in 30 mL of water, and 12 mL of 50 vol.-% hydrochloric acid is added. The solution is filled up to a defined volume of 100 mL. This work up is repeated three times independently; additionally, a blank sample is pre pared for reference purposes.

Measurement:

Li, Ca, Mn within the obtained solution is determined by optical emission spectroscopy us ing an inductively coupled plasma (ICP-OES). Instrument: ICP-OES Agilent 5100 SVDV; wavelengths: Li 670.783 nm; Ca 396.847 nm; Mn 257.610 nm; internal standard: Sc 361.383 nm; dilution factors: Li 100, Ca 10, Mn 100; calibration: external.

Elemental analysis of fluorine and fluoride is performed in accordance with standardized methods: DIN EN 14582:2016-12 with regard to the sample preparation for the overall fluo rine content determination (waste samples); the detection method is an ion selective elec trode measurement. DIN 38405-D4-2:1985-07 (water samples; digestion of inorganic solids with subsequent acid-supported distillation and fluoride determination using ion selective electrode).

Other metal impurities and phosphorous are determined analogously by elemental analysis using ICP-OES (inductively coupled plasma - optical emission spectroscopy) or ICP-MS (inductively coupled plasma - mass spectrometry). Total carbon is determined with a ther mal conductivity detector after combustion.

Phase compositions of solids [including the identification of manganese(ll)oxide, and Ni and Co in an oxidation state lower than +2 (typically metallic) in the particulate material provid ed in present step (a)] are determined with powder x-ray diffraction (PXRD). The method is performed as follows:

The sample is ground to fine powder and filled in the sample holder.

Two devices, each using its specific radiation source, are employed: (1) Measurement applying Cu radiation: The instru ment used is a Bru ker D8 Advance Series 2 with an auto-sampling unit; primary side: Cu-anode, beam spread angle aperture 0.1° with ASS; secondary side: Scattered beam aperture 8 mm with Ni 0,5 mm, Soller 4° , Lynx- Eye (3° aperture) .

(2) Measurement applying Mo radiation: The instrument used is a Bru ker D8 Discover A25 with an auto-sampling u nit; primary side: Mo-anode with Johansson monoch romator (Mo- K-al phal) with axial sol ler 2.5° ; secondary side: ASS, Sol ler 2.5° , Lynx-Eye XE detector (3.77° apertu re) .

References are used to identify matches with the obtained reflection pattern. Al l relevant phases are wel l known in the literature; the fol lowing references are consu lted and used in order to calculate the theoretical diffraction pattern (see position and intensity of re flections in Table 1 below) : a) CO _x Ni _1-x ; space grou p Fm-3m;

x = 0.5: Taylor et a I ., J. I nst. Met. (1950) 77, 585-594.

x = 0: Buschow et a I .; J . Magn. Magn. Mater. 1983, 38, 1-22.

b) Co; space group P6 ₃ /m mc; Buschow et a I . ; J. Magn. Magn. Mater. 1983, 38, 1-22. c) Li2CO3, space grou p C2/c; J. Al loys Compd. (2011), 509, 7915-7921

d) LiAI02, space group R-3m; Marezio et a I . , J. Chem. Phys. (1966) 44, 3143-3145. e) M nO, space group Fm-3m, Locmelis et a I . , Z. Anorg. Al lg. Chem. 1999, 625, 1573.

Tab. 1: Characteristic reflections (position given in ° 2theta and relative intensity in %) of CoxN il-x, Co, Li2CO3, LiAI02 and M nO with intensities >10% and 2theta <80° for Cu K al pha 1 radiation) :

In case of characteristic reflections overlapping with reflections of different crystalline phases (especially graphite, which contributes the largest fraction of the sample), an addi tional measurement employing an alternative radiation source (e.g. Mo K alpha instead of Cu K alpha) is performed.

Abbreviations:

In the context of the present invention, normal pressure means 1 atm or 1013 mbar.“Nor mal conditions”mean normal pressure and 20° C. Nl stands for normal liter, liter at normal conditions (1 atm, 20° C). PFA stands for perfluoroalkoxy polymer.

Percentages refer to % by weight unless specifically defined otherwise. The expressions % by weight and wt% may be used interchangeably. Wherever mentioned, the terms“room temperatu re” and“ambient tem perature” denote a temperature between about 18 and 25° C. XRD denotes powder x-ray investigation (radiation as indicated, typical ly Cu k- al phal radiation of 154 pm or Mo k-al phal of 71 pm) .

The invention is fu rther il lustrated by the fol lowing examples.

Example 1: Providing a reduced mass from waste lithium ion batteries

An amount of aboutl t mechanical ly treated battery scrap containing spent cathode active material containing nickel, cobalt and manganese, organic carbon in the form of graphite and soot and residual electrolyte, and further impu rities inter alia com prising fluorine com pou nds, phosphorous and calcium is treated to obtain a reduced mass according to the process described in Jia Li et a I . , Jou rnal of Hazardous Materials 302 (2016) 97-104. The atmosphere within the roasting system is air whose oxygen reacts with the carbon in the battery scrap to form carbon monoxide, treatment tem peratu re is 800° C.

After reaction and cool down to ambient tem perature, the heat-treated material is recovered from the fu rnace, mechanical ly treated to obtain a particu late material and analyzed by means of X-ray powder diffraction (Fig. 1 and 2: Mo Ka radiation, Fig. 3 and 4: Cu Ka radiation) , elemental analysis (Tab. 2) and particle size distribution (Tab. 3) .

The Li content is 3.6 wt.-%, which acts as reference for al l fu rther leaching examples (see below) . Fluorine is main ly represented as i norganic fluoride (88%) . Particle sizes are wel l below 1 mm; D50 is determined to be 17.36 pm.

Com paring the obtained XRD pattern with calculated reference patterns of N i (which is identical with that one of CoxNil-x, x = 0-0.6), Co, Li2CO3 and LiAI02 (see reference patterns in Tab. 1) , it can be concluded that Ni is exclusively present as metal lic phase, either as pu re Ni or as an al loy in combination with Co. For clarity, this result is confirmed by applying two different radiation sou rces. The presence of metal lic nickel is su pported by the qualitative observation that the whole sam ple shows typical ferromagnetic behavior when it gets in touch with a permanent magnetic material. As lithiu m salts, Li2CO3 as wel l as LiAI02 are clearly identified by their characteristic diffraction pattern.

The com position of the black powder (PM) obtained is shown in Table 2.

Tab. 2: Composition of reduced black powder (PM)

Tab. 3: Results on particle size distribution measu rement of reduced mass from waste lithiu m ion batteries after heat treatment.

Example 2: Leaching with Ca(OH)2

An amou nt of 5 g of the above-mentioned reduced battery scrap material (obtained as shown in Exam ple 1) is fil led an a PFA flask and mixed with 5, 1.5, 1.0 and 0.5 g of solid Ca(OH)2, respectively. 200 g of water are added with stirring, and the whole mixture is refluxed for 4 hou rs.

After 4 hou rs, the solid content is filtrated off and filtrate sam ples are taken and analyzed with regard to Li, F, carbonate, OH, and Ca. Results are compiled in the below Table 4.

Tab. 4: Analyzed filtrates after Li leaching with Ca(OH)2.

Example 2a: Leaching with Ca(OH)2, addition of solids to liquid

Exam ple 2 is repeated except that 5 g of the black powder obtained as shown in Example 1, and the designated amount of solid Ca(OH)2, are added simultaneously to 200 g of water with stirring. Resu lts are analogous to those reported in Table 4.

Example 3: Higher solid content

An amou nt of 10, 20 and 30 g, respectively, of the particu late material (PM) described in exam ple 1 is fil led an a PFA flask and mixed with solid Ca(OH)2 in a fixed weight ratio of PM : Ca(OH)2 = 3.3 : 1. The fu rther treatment with addition of 200 g of water fol lows example 2 except that each sample is refluxed for 6 hou rs. Results are shown in Table 5.

Based on these results, it is concluded that the efficiency of the present leaching process is not affected by the PM solid content. Tab. 5: Analyzed filtrates after Li leaching with Ca(OH)2.

Example 4: Variation of parameters

Fol lowing the procedu re of Exam ple 2a, solid Ca(OH)2 and the particulate material (PM) described in exam ple 1 is added with stirring (3 stages cross-beam stirrer , 60 mm diameter) to 836.8 g of pre-heated water in a glass reactor with baffles. The stirring is continued at constant tem peratu re for the time period (t) indicated in Tab. 6, after which the solid is filtered off and filtrate samples are analyzed. Amou nts of Ca(OH)2 and PM, tem peratu res, stirring parameters, and analysis resu lts (% = g found in 100g of filtrate) are also com piled in Table 6.

Tab. 6:

Example 5: Solid LiOH from leached lithium filtrate

A filtrate obtained from a process according to example 2 is fu rther treated according to the above described step (el) to yield solid LiOH as monohyd rate: 1L of a filtrate containing 0.21 wt.-% lithiu m is concentrated by evaporation (40° C, 42 mbar)and final ly d ried applying 40° C and a constant flow of nitrogen for 24 h. Fig. 5 shows the obtained LiOH

monohydrate with minor impu rities of Li2CO3. The latter is due to contact with air du ring al most al l process steps. Next to carbon-based impurities, elemental analysis reveals as main im pu rities (>200 ppm) F, Na, Ca, K and Cl and minor impurities (<200 ppm) of Al and Zn.

Example 6: Lab-scale smelting The particu late mass (black powder) described in example 1 is leached according to exam ple 4 for 6 h. The leached residue obtained after filtration contains approx. 2.2% total fluorine, 26.3% carbon, 13.9% calciu m, 8% cobalt, 2.9% copper, 0,2% lithiu m, 4.9%

manganese, 4.8% nickel and 0,3% phosphorous as d ry mass. 4.23 kg of this material is slu rried in water, additivated with 0.63 kg of fine quartz sand (d50 approx. 80 pm) , 0.01 kg of calcium oxide and 0.51 kg of molasses. The slu rry is filtered and extruded by an extruder press into a 6 m m strand. This strand is d ried and calcined at 700° C and broken into pieces of less than 1 cm length. This material is the feed for a smelting experiment in a lab- scale electric arc fu rnace.

A graphite crucible of 180 mm in ner diameter and a height of 210 m m, whose inner wal l su rface (except for the bottom) is covered by an alu mina paper of 5 mm thickness and lined with a ch romium corundum casting (87,5% AI203, 10,5% Cr2O3, 2% CaO) of 30 m m thickness previously dried for 18h at 120° C fol lowed by a bu rning at 515° C for 18 h, is placed into a lab-scale electric arc fu rnace and em bedded with graphite felt and sealed on top with refractory mortar. The crucible is then charged with coke and pre-heated with an open electric arc at 35 V and 100 A from the 50 m m diameter head electrode u ntil the bottom and the surrounding side wal ls of the oven are glowing (approx. 950° C). The coke is then discharged by tilting of the oven. Afterwards 516 g of carbon satu rated cast iron serving as counter electrode for the electric arc are fil led into the oven together with 250 g of feed material. After about 10 min the material is molten and the rest of the feed material is charged into the fu rnace in 100 g portions with 2 min between each charge. The electric power is increased to 11 kW (50 V, 225 A) . After completion of the charging, the

tem peratu re in the oven is at approx. 1600° C. The electric power is reduced to 9 kW (60 V, 150 A) and the melt is kept for 10 min. Afterwards the electric power is switched off and the oven is cooled down to ambient temperature overnight. The cold crucible is discharged from the oven and crushed. At the bottom of the crucible about 1 kg of an al loy containing main ly nickel, cobalt and copper from the battery scrap material and iron.

The al loy components are separated according to methods known in the art.

Brief description of Figu res:

Fig. 1: X-ray powder diffractogram (Mo Ka) of reduced mass from waste lithium ion batteries after heat/reduction treatment as obtained in exam ple 1 and used in exam ple 2a including reference diffractograms of graphite, cobalt, manganese-l l-oxide, cobalt oxide, and nickel.

Fig. 2: X-ray powder diffractogram (Mo Ka) of reduced mass from waste lithiu m ion batteries after heat/reduction treatment as obtained in example 1 and used in example 2a including reference diffractograms of graphite, lithiu m alu minate, and lithium carbonate.

Fig. 3: X-ray powder diffractogram (Cu Ka) of reduced mass from waste lithiu m ion batteries after heat/reduction treatment as obtained in exam ple 1 and used in example 2a including reference diffractograms of graphite, cobalt, manganese-l l-oxide, cobalt oxide, and nickel.

Fig. 4: X-ray powder diffractogram (Cu Ka) of reduced mass from waste lithiu m ion batteries after heat/reduction treatment as obtained in exam ple 1 and used in exam ple 2a including reference diffractograms of graphite, lithiu m aluminate, and lithium carbonate.

Fig. 5: X-ray powder diffractogram (Cu Ka) of LiOH monohyd rate as obtained in example 5.