BATTERY RECYCLING BY REDUCTION AND CARBONIZATION

Abstract

The present invention relates to a process for the recovery of transition metals from battery materials comprising (0.1) providing a battery material comprising nickel oxide and / or cobalt compounds, (1.1) heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt, (2.1) carbonylating the reduced material with carbon monoxide, optionally in the presence of a reactive gas, to produce a solid carbonylation residue and a volatile carbonyl comprising compounds containing nickel and / or cobalt carbonyl, and (3.1) separating the volatile carbonyl from the solid carbonylation residue by evaporation.

Description

BATTERY RECYCLING BY REDUCTION AND CARBONYLATION The present invention relates to a process for the recovery of transition metals from battery materials comprising (0.1) providing a battery material comprising nickel oxide and / or cobalt compounds, (1.1) heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt, (2.1) carbonylating the reduced material with carbon monoxide, optionally in the presence of a reactive gas, to produce a solid carbonylation residue and a volatile carbonyl comprising compounds containing nickel and / or cobalt carbonyl, and (3.1) separating the volatile carbonyl from the solid carbonylation residue by evaporation. The lifespan of batteries, especially lithium-ion batteries, is not unlimited. It is therefore expected that an increasing number of spent batteries will be generated. Since they contain important transition metals, such as cobalt and nickel, among others, as well as lithium, spent batteries can constitute a valuable source of raw materials for a new generation of batteries. For this reason, research efforts have intensified with the aim of recycling the transition metals—and, optionally, even the lithium—from used lithium-ion batteries. Several processes have been identified for recovering raw materials. One process involves melting the corresponding battery scrap, followed by hydrometallurgical treatment of the resulting metal alloy. Another process is the direct hydrometallurgical treatment of battery waste materials. These hydrometallurgical processes yield transition metals as aqueous solutions or in precipitated form, for example, as hydroxides, either separately or already in the desired stoichiometries for producing a new active cathode material. The process of the present invention pursues several objectives: Easy, inexpensive, fast, and / or efficient recovery of transition metals, such as nickel and / or cobalt. Prevention of the introduction of new impurities into the process that would require an additional purification stage. The object was achieved by a process for the recovery of transition metals from battery materials comprising (0.1) providing a battery material comprising nickel oxide and / or cobalt compounds, (1.1) heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt, (2.1) carbonylating the reduced material with carbon monoxide, optionally in the presence of a reactive gas, to produce a solid carbonylation residue and a volatile carbonyl comprising compounds containing nickel and / or cobalt carbonyl, and (3.1) separating the volatile carbonyl from the solid carbonylation residue by evaporation. In a preferred embodiment, the process for recovering transition metals from battery materials comprises (0.1) providing a battery material comprising nickel oxide and / or cobalt compounds, such as complete batteries, mechanically treated waste batteries, or battery waste, (0.2) optionally washing the battery material with an organic solvent to remove the organic electrolyte and polymeric binder, (0.3) optionally washing the battery material with an aqueous medium, (0.4) optionally subjecting the battery material to solid-solid separation, such as flotation, electroclassification, sieving, or magnetic separation, to remove solids, such as carbon, polymers, or magnetic material, (0.5) optionally heating the battery material to 350°C to evaporate the organic components of the electrolyte, (1.(1) heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt, (1.2) optionally, subjecting the reduced material to a solid-dry separation, such as electroclassification, sieving or magnetic separation, to remove solids, such as carbon, polymers or magnetic material, (1.3) optionally, treating the reduced material with an aqueous medium, optionally acidic, to produce a suspension containing a dissolved lithium salt and undissolved material, optionally, subjecting the suspension to a solid-liquid separation to separate the dissolved lithium salt from the undissolved material, and optionally, subjecting the undissolved material to a solid-solid separation to remove solids, such as carbon, polymers or magnetic material, or undissolved lithium salts, (2.(3.1) carbonylate the reduced material with carbon monoxide, optionally in the presence of a reactive gas, at a temperature of 30 to 300°C and a partial pressure of 1 to 300 bar, to produce a solid carbonylation residue and a volatile carbonyl selected from compounds containing nickel and / or cobalt carbonyl, (3.2) separate the volatile carbonyl from the solid carbonylation residue by evaporation, (3.3) optionally purify the separated volatile carbonyl by adsorption, condensation, distillation or vaporization, (3.4) optionally decompose a non-volatile solid metal carbonyl in the solid carbonylation residue, (3.5) optionally subject the solid carbonylation residue to a dry solid-solid separation, such as electroclassification, sieving or magnetic separation, to remove solids such as carbon, polymers or magnetic material, (3.5) Optionally treat the solid carbonylation residue with an optionally acidic aqueous medium to produce a suspension containing a dissolved lithium salt and undissolved material, optionally subjecting the suspension to a solid-liquid separation to separate the dissolved lithium salt from the undissolved material, optionally subjecting the undissolved material to a solid-solid separation to remove solids such as carbon, polymers, magnetic material or undissolved lithium salts. IVIA / a / ZUZZ / UII / and I (4.1) optionally, decompose the volatile carbonyl to produce nickel and / or cobalt in elemental form or as salts, and (4.2.) optionally, further purify the nickel and / or cobalt. In another preferred form, the process comprises at least one of the steps (0.2), (0.3), (0.4), (0.5), (1.2), (1.3), (3.2), (3.3), (3.4), (3.5) and (4.2). In another more preferred form, the process comprises at least one of the steps (0.1), (1.1), (2.1), (3.1), (3.5), (4.1). The recovery of transition metals from batteries, such as lithium-ion batteries, typically means that transition metals (e.g., nickel, cobalt, and / or manganese) and, optionally, other valuable elements (e.g., lithium and / or carbon) can be recovered at least partially, usually with a recovery rate of at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 95% or 99% by weight for each. Preferably, the process recovers at least nickel, cobalt, and / or lithium. Transition metals and, optionally, other valuable elements are recovered from batteries, preferably lithium-ion batteries, such as used or new batteries, battery parts, off-specification cathode active materials (e.g., not meeting specifications and requirements), or production waste from battery manufacturing. Step (0) Provide and prepare the battery material Step (0.1) consists of providing a battery material comprising nickel oxide and / or cobalt compounds, such as complete batteries, mechanically treated waste batteries, or battery waste. Battery material is material derived from batteries, preferably lithium-ion batteries. For safety reasons, these batteries are usually fully discharged, as otherwise short circuits can occur, posing fire and explosion risks. These lithium-ion batteries can be disassembled, drilled, ground (for example, in a hammer mill), or crushed (for example, in an industrial crusher). This type of mechanical processing yields the active material from the battery electrodes, which contains a transition metal material that can have a regular shape but is usually irregular. However, it is preferable to remove as much of the lighter fraction, such as casing parts made of organic plastics and aluminum or copper foil, as possible, for example, through forced gas flow, air separation, or classification. In one way, the battery material is present in the form of complete batteries. The battery material is typically derived from battery scrap, such as lithium-ion batteries. This battery scrap may come from used batteries or production waste, such as off-specification material. In a preferred form, the transition metal material is obtained from mechanically processed battery waste, for example, from battery waste processed in a hammer mill or industrial shredder. This transition metal material may have a mean particle diameter (D50) in the range of 1 µm to 1 cm, preferably from 1 to 1000 µm, and particularly from 3 to 500 µm. Larger parts of the battery scrap, such as casings, wiring, and electrode carrier sheets, are typically mechanically separated so that these materials can be largely excluded from the transition metal material used in the process. Preferably, the battery material is present in the form of complete batteries or mechanically treated battery scraps. The battery material may contain lithium and its compounds, carbon in an electrically conductive form (e.g., graphite, soot, and graphene), solvents used in electrolytes (e.g., organic carbonates such as diethyl carbonate), aluminum and aluminum compounds (e.g., alumina), iron and iron compounds, zinc and zinc compounds, silicon and silicon compounds (e.g., silica, silicates, and oxidized silicon SiO₂ with 0 < and < 2), tin, silicon-tin alloys, and organic polymers (such as polyethylene, polypropylene, and fluorinated polymers, e.g., polyvinylidene fluoride), fluoride, and phosphorus compounds (which may come from liquid electrolytes, e.g., in the widely used LiPFe and products from the hydrolysis of LiPFe). The battery material may contain between 1 and 61% by weight, preferably between 2 and 30% by weight, and in particular between 4 and 18% by weight of nickel oxide. The battery material may contain between 1 and 61% by weight, preferably between 2 and 30% by weight, and in particular between 4 and 20% by weight of cobalt oxide. The battery material may contain between 1 and 59% by weight, preferably between 2 and 30% by weight, and in particular between 4 and 20% by weight of manganese, as metal or in the form of one or more of its compounds. The battery material may contain between 0.5 and 12% by weight, preferably between 1 and 8% by weight, and in particular between 1 and 5% by weight of lithium, either as metal or in the form of one or more of its compounds The battery material may contain from 100 ppm to 15% by weight of aluminum, as metal or in the form of one or more of its compounds. The battery material may contain from 20 ppm to 3% by weight of copper, either as metal or in the form of one or more of its compounds. The battery material may contain 100 ppm to 5% by weight of iron, as metal or alloy, or in the form of one or more of its compounds. The transition metal material may contain 20 ppm to 2% by weight of zinc, as metal or alloy, or in the form of one or more of its compounds. The battery material may contain 20 ppm to 2% by weight of zirconium, as metal or alloy, or in the form of one or more of its compounds. The battery material may contain 20 ppm to 2% by weight of tungsten, as metal or alloy, or in the form of one or more of its compounds. The battery material may contain 0.5% to 10% by weight of fluorine, calculated as the sum of organic fluorine bound in polymers or organic additives and inorganic fluorine in one or more of its inorganic fluorides. The battery material may contain 0.2% to 10% by weight of phosphorus. The phosphorus may occur in one or more inorganic compounds. Battery material typically contains cobalt and, in most cases, at least one nickel and one manganese. Examples of these transition metal materials may be based on LiCoO2, lithified nickel-cobalt-manganese oxide (“NCM”), or lithified nickel-cobalt-aluminum oxide (“NCA”), or mixtures thereof. Examples of stratified nickel-cobalt-manganese oxides are compounds of the general formula Lii+x(NiaCobMncM1d)i x02 where M1 is selected from Mg, Ca, Ba, Al, Ti, Zr, Zn, Mo, V and Fe, the additional variables being defined as follows: zero < x < 0.2, zero < a < 0.8, 0.05 < b < 1, preferably 0.05 < b < 0.5, zero < c < 0.6, zero < d < 0.1, a + b + c + d = 1. The preferred stratified nickel-cobalt-manganese oxides are those in which M1 is selected from Ca, Mg, Zr, Al and Ba, and the other variables are defined as indicated above. The preferred layered nickel-cobaltomanganese oxides are Li(i+x)[NiO.33CoO.33Mno.33](ix)O2, Li(i+x)[NiO5CoO.2Mno.3](ix)O2, Li(i+x)[NiO.6CoO.2Mno.2](ix)O2, Li(i+x)[NiO.7CoO.2MnO.3](ix)O2 and Li(i+x)[NiO.8CoO.iMno.i](ix)O2, each of them with x as defined above. Examples of nickel-cobalt-lithium oxides are compounds of general formula Li[NiHCoAlj]O2+r, where h is in the range of 0.8 to 0.90, i is in the range of 0.15 to 0.19, j is in the range of 0.01 to 0.05, and r is in the range of zero to 0.4. Step (0.2) optionally consists of washing the battery material with an organic solvent to remove the organic electrolyte or polymeric binder. Step (0.2) is preferably used when the battery material is presented as mechanically treated battery scrap and can help dissolve and separate the polymeric binders used to bond the transition metal oxides to the current collector films or, for example, to bond the graphite to the current collector films. Suitable solvents are N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N-ethylpyrrolidone, and dimethyl sulfoxide, in pure form, as mixtures of at least two of the above, or as a mixture with 1 to 99% by weight of water. Step (0.3) optionally consists of washing the battery material with an aqueous medium. Step (0.3) is preferably used when the battery material is presented as mechanically treated battery scrap and can help remove liquid impurities and water-soluble impurities from the battery material. This washing step can be enhanced by grinding, for example, in a ball mill or a stirred ball mill. The washed battery material can be recovered by a solid-liquid separation step, for example, filtration or centrifugation, or any type of sedimentation and decantation. To promote the recovery of finer particles of this solid transition metal material, flocculants, for example, polyacrylates, can be added. Step (0.4) optionally involves subjecting the battery material to solid-solid separation, such as flotation, electrosorting, screening, or magnetic separation, to remove solids, including carbon, polymers, or magnetic material, or a combination of at least two of these operations. Step (0.4) is preferably used when the battery material is present as mechanically treated battery scrap and can help remove carbon and / or polymeric materials. Examples of solid-solid separation steps include classification, gravity concentration, flotation, dense media separation, magnetic separation, and electrosorting. Generally, an aqueous slurry obtained before step (0.4) can be subjected to solid-solid separation, except in the case of electrosorting, which is carried out under dry conditions.The solid-solid separation stage is usually used to separate insoluble hydrophobic components, such as carbon and polymers, from metallic or metal oxide components. The solid-solid separation stage can be carried out by mechanical, column, pneumatic, or hybrid flotation. Collector compounds can be added to the suspension to make the hydrophobic components even more hydrophobic. Suitable collector compounds for carbon and polymeric materials are hydrocarbons or fatty alcohols, introduced in quantities of 1 g / t to 50 kg / t of transition metal material. It is also possible to perform flotation in reverse, that is, by transforming the originally hydrophilic components into strongly hydrophobic ones using special collectors, such as fatty alcohol sulfates or esterquats. Direct flotation using hydrocarbon collectors is preferred. To improve the selectivity of the flotation towards carbon particles and polymeric material, suppressant agents can be added to reduce the amounts of metallic components and metal oxides carried over in the froth phase. The suppressant agents that can be used are acids or bases to control the pH value within a range of 3 to 9, or ionic components that can adsorb onto more hydrophilic components. To increase the efficiency of the flotation, it can be advantageous to add carrier particles that form agglomerates with the hydrophobic target particles under the flotation conditions. Magnetic or magnetizable metallic components or metal oxides can be separated using low-, medium-, or high-intensity magnetic separators, depending on the susceptibility of the magnetizable components. It is also possible to add magnetic carrier particles. These magnetic carrier particles are capable of forming agglomerates with the target particles. In this way, non-magnetic material can also be removed using magnetic separation techniques. Preferably, the magnetic carrier particles can be recycled within the separation process. The solid-solid separation steps typically yield at least two fractions of solid materials present as suspensions: one containing mainly the battery material with cobalt and nickel, and another containing mainly the carbonaceous and polymeric components of the battery. The first fraction can be fed into step (1.1), while the second can be further treated to recover the different components, i.e., the carbonaceous and polymeric material. Step (0.5) optionally consists of heating the battery material to 350°C to evaporate the organic components of the electrolyte and decompose the polymeric components of the binder. Step (0.5) is preferably used when the battery material is supplied as mechanically treated battery scrap and can help evaporate residual solvents from the battery electrolyte. This heat treatment is preferably performed instead of optional steps (0.2) and (0.3). Stage (1) - Battery material reduction and processing Step (1.1.) consists of heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt. The battery material that is heated in stage (1.1) can be obtained from stages (0.1), (0.2), (0.3), (0.4) or (0.5). The battery material is usually heated to a temperature between 350 and 900°C, preferably between 350 and 600°C, and more preferably between 350 and 500°C. The warm-up can last from 10 minutes to 30 hours, preferably from 20 minutes to 8 hours, more preferably from 30 minutes to 4 hours. After heating, the reduced material can be cooled, for example, to room temperature or slightly above room temperature, for example, from 25 to 90°C. Step (1.1.) can be carried out in the presence of lime, quartz, or silicate, with lime being preferable. The lime can be selected from slaked lime and quicklime. Typically, there can be between 2 and 40% by weight of lime, quartz, or silicate, relative to the battery material. Step (1.1) is preferably carried out by heating the battery material in an inert atmosphere of hydrogen or oxygen. More preferably, step (1.1) is carried out by heating the battery material to a temperature of 350 to 900°C in an inert atmosphere of hydrogen or oxygen. The hydrogen atmosphere can contain from 0.1% to 100% hydrogen by volume. Preferably, it contains from 3% to 100% hydrogen by volume, with the remainder being a non-oxidizing gas, preferably nitrogen, argon, steam, carbon monoxide, carbon dioxide, or mixtures of at least two of these gases. The preferred non-oxidizing gases are nitrogen and steam, and mixtures of nitrogen and steam. The hydrogen concentration in the reduction atmosphere and the reaction time are interdependent. Generally, a low hydrogen concentration requires longer reduction times, and vice versa. The hydrogen atmosphere is applied at a total pressure of 0.1 to 300 bar, preferably from 1 to 100 bar and, more preferably, at an ambient pressure of 1 bar or only slightly higher up to 5 bar. Heating can be carried out in any type of furnace that allows the introduction of different gases. These furnaces can operate in batches or continuously. Rotary kilns and fluidized bed reactors are preferred. These reactors can operate continuously. Different gas compositions can be applied in consecutive furnaces or chambers, or in consecutive sections of the furnace. In the latter case, the gases are introduced in such a way as to prevent the mixing of reactive gases. The inert atmosphere may contain nitrogen or rare gas, preferably nitrogen. Nickel and / or cobalt oxides may be reduced under the inert atmosphere by carbon or organic matter, which typically comes from batteries or their decomposition products. The oxygen atmosphere can contain some oxygen, for example, from 2 to 10% by volume. In one sense, the oxygen atmosphere is air. Nickel and / or cobalt oxides can be reduced under the oxygen atmosphere by carbon or organic matter, which often comes from batteries and can form a reducing atmosphere through partial combustion in the oxygen atmosphere. In another way, the composition of the atmosphere can change, for example, in the case of volatile organic compounds in the feed that will be removed in an inert atmosphere before changing the atmosphere to an oxygen atmosphere. In another form, the atmosphere contains vapor, for example, under an inert atmosphere containing water in a gaseous state or air containing water in a gaseous state. In one form, the reduction conditions in step (1.1) are chosen such that at least a portion of the battery material contains para-, ferro-, or ferrimagnetic components that can be separated by applying a magnetic field, as in step (1.2). The formation of ferro- or ferrimagnetic components resulting from at least partial reduction of the battery material is preferred. Nickel and / or cobalt oxides can be reduced in step (1.1) to elemental nickel and / or cobalt in an amount of at least 50, 60, 70, 80, 90 or 95% by weight. Heating can be carried out in externally heated furnaces, such as electrically heated furnaces and fluidized bed reactors, or in furnaces with internal burners, such as rotary kilns. Heat treatment can also be performed in vacuum furnaces. Heat treatment can be carried out over a wide pressure range, from 0.001 bar to 100 bar. It is preferable to perform the heat treatment at a pressure slightly above 1 bar, at ambient pressure, or below. In one embodiment, heating can be carried out in a smelting furnace that produces a metal alloy containing nickel and / or cobalt and a slag material. Typically, the feed material is pelletized and premixed with slag-forming additives and fluxes (e.g., soda ash, potash, lime, borax). Suitable smelting furnaces include bath smelting furnaces, top-blown rotary converters, shaft furnaces, electric arc furnaces, plasma furnaces, and others. The furnace can operate in continuous or batch mode. The extracted alloy is usually fed into a spray dryer, granulator, or casting mold (continuous or batch). The slag is typically fed into a slag cooling pool or an underwater granulation device, or it is sprayed by a strong gas stream into small droplets that cool on their descent. Step (1.2) optionally consists of subjecting the reduced material to a dry solid-solid separation, such as electroclassification, sieving or magnetic separation, or eddy current separation, to remove solids such as carbon, polymers, magnetic material or non-ferrous metals. Step (1.3) is optionally to treat the reduced material with an aqueous medium, optionally acidic, to produce a suspension containing a dissolved lithium salt and undissolved material, optionally to subject the suspension to a solid-liquid separation to separate the dissolved lithium salt from the undissolved material, and optionally to subject the undissolved material to a solid-solid separation to remove solids such as carbon, polymers, magnetic material or undissolved lithium salts. The suspension usually contains dissolved lithium salts, such as LIOH, LIHCOs and / or LI2CO3 or the lithium salts of the acids used. Solid-liquid separation can be filtration, centrifugation, sedimentation, or decantation. The aqueous medium must be capable of selectively dissolving the lithium components without dissolving the transition metals. This treatment can be carried out at room temperature or at higher temperatures, for example, in the range of 20 to 150°C. If temperatures above the boiling point of water are used, the treatment is carried out at elevated pressures. Preferably, the aqueous medium contains a weak acid (for example, carbonic acid, formic acid, acetic acid, or sulfurous acid) or a strong acid (for example, sulfuric acid, hydrochloric acid, nitric acid), with weak acids being preferable. These acids are typically used at concentrations of 0.1 to 10% by weight in water, preferably 1 to 10% by weight. When carbonic acid is used, it is preferable to use it under a carbon dioxide pressure of 10 to 150 bar. In one form, the aqueous medium is water, for example, deionized water.Alternatively, the reduced material is first treated with water and then with a dilute weak acid after a solid-liquid separation, such as filtration following the water treatment. The two extracts can be kept separate to isolate the different dissolved Li species. The treatment with the aqueous medium can last from 20 minutes to 10 hours, preferably from 1 to 8 hours. The ratio of the aqueous medium to the reduced material can range from 1:1 to 99:1, preferably from 2:1 to 9:1 by weight. Step (2) - Carbonylation of the reduced material Step (2.1) consists of carbonylating the reduced material with carbon monoxide, optionally in the presence of a reactive gas, to produce a solid carbonylation residue and a volatile carbonite comprising compounds containing nickel and / or cobalt carbonite. Carbonylation can be carried out at a temperature of 30 to 300°C, preferably 70 to 250°C. Carbonylation can be carried out at a pressure of 1 to 300 bar, preferably from 50 to 300 bar. Preferably, step (2.1) consists of carbonylating the reduced material with carbon monoxide at a temperature of 70 to 250°C and a partial pressure of CO of 50 to 300 bar. The reduced material that is carbonylated can be obtained from step (1.1), (1.2) or (1.3). IVIA / a / ZUZZ / UII / and I The volatile carbonyl generally comprises Ni(CO)4, HCo(CO)4 and / or (NO)Co(CO)3. Preferably, the volatile carbonyl comprises NI(CO)4, HCo(CO)4 or a mixture of Ni(CO)4, HCo(CO)4. In addition to carbon monoxide, there may be an inert gas and / or a reactive gas during carbonylation. The inert gas can be nitrogen, argon, or carbon dioxide. The inert gas can be present at up to 90% of the volume. In a preferred form in which the reduced material contains mainly nickel and no or small amounts of cobalt, the inert gas is present during carbonylation. The reactive gas can be hydrogen or nitric oxide. It can be present in up to 90% of the volume. Preferably, the reactive gas is present when cobalt is present in the reduced material. Reactive gas may be present when the reduced material contains smaller amounts (e.g., up to 10, 5 or 1% by weight) or is nickel-free. Carbonylation can be carried out in two or more stages under varying conditions. In one form, nickel and cobalt are present in the reduced material, and the reduced material is carbonylated first in the absence of a reactive gas to produce a volatile nickel carbonyl, and then in the presence of a reactive gas to produce a volatile cobalt carbonyl. In another form, nickel and cobalt are present in the reduced material, and the reduced material is carbonylated first in the presence of a reactive gas to produce a volatile cobalt carbonyl, and then in the absence of a reactive gas to produce a volatile nickel carbonyl. Depending on the composition, it may be beneficial to repeat this step several times. A carbonylation catalyst (such as ammonia, sulfur, or sulfur compounds (e.g., hydrogen sulfide, carbon disulfide, or sulfur dioxide)) may be present during carbonylation in the absence or presence of a reactant gas. In a preferred form where the reduced material contains mainly nickel (e.g., at least 50, 70, or 90 wt%) and preferably no or small amounts of cobalt (e.g., less than 50, 20, or 10 wt%), a carbonylation catalyst may be present. The carbonylation catalyst may be added together with the carbon monoxide, or the reduced material may be pretreated with it. Between the two stages, any non-volatile carbonyl formed in the solid carbonylation residue can be decomposed by heating and / or pressure release. The carbonylation reaction time can be 1 to 4 days, preferably 1 to 2 days. Step (3) - Separation and purification of volatile carbonyls Step (3.1) consists of separating the volatile carbonyls from the solid carbonylation residue by evaporation. The temperature during separation must be kept below the decomposition temperature and above the boiling point of the volatile carbonyl. For example, nickel tetracarbonyl is stable up to temperatures of around 180°C at ambient pressure, and cobalt tetracarbonyl hydride is stable at carbon monoxide partial pressures of 20 bar at 110°C to 300 bar at 200°C. The separation of the volatile carbonyl can take place during the carbonylation of step (2.1). The pressure and composition of the gas in step (2.1) (e.g., the partial pressure of carbon monoxide, inert gas, or hydrogen or nitrogen oxides) are preferably selected so that the separation can be carried out at the lowest possible temperature. Step (3.2) consists of optionally purifying the separated volatile carbonyl by adsorption, condensation, distillation or vaporization. Volatile carbonyls can be condensed at temperatures below their respective boiling points, which depend on the applied pressure. From the condensed volatile carbonyls, low-boiling carbonyl compounds can be obtained in pure form by distillation or as pure compounds separated by fractional distillation, preferably under an atmosphere containing carbon monoxide. The volatile carbonyl group can also adsorb onto organic solvents, water, or aqueous media. Cobalt tetracarbonyl hydride can be adsorbed onto an aqueous medium, such as alkaline hydroxide solutions. Step (3.2) can help to remove unwanted volatiles (e.g., iron carbonyls), or to isolate at least one of the volatile carbonyls, e.g., nickel carbonyl or cobalt carbonyl. The solid carbonylation residue can be further processed, for example, for the recovery of the remaining transition metals. The appropriate processing steps for the solid carbonylation residue are steps (3.3), (3.4) and / or (3.5). Step (3.3) optionally consists of decomposing a non-volatile metal carbonyl in the solid carbonylation residue. Decomposition can be achieved by heating the solid carbonylation residue and / or releasing pressure from the solid carbonylation residue. Step (3.4) optionally consists of subjecting the solid carbonylation residue to a dry solid-solid separation, such as electroclassification, sieving or magnetic and eddy current separation, to remove solids such as carbon, polymers or magnetic material. Step (3.5) is optionally to treat the solid carbonylation residue with an optionally acidic aqueous medium to produce a suspension containing a dissolved lithium salt and undissolved material, optionally to subject the suspension to a solid-liquid separation to separate the dissolved lithium salt from the undissolved material, and optionally to subject the undissolved material to a solid-solid separation to remove solids such as carbon, polymers, magnetic material or undissolved lithium salts. Optional step (4) - Decomposition of volatile carbonyl Step (4.1) consists of optionally decomposing the volatile carbonyl to produce nickel and / or cobalt in elemental form or as salts. The volatile carbonyl that decomposes can be obtained from step (3.1) or (3.2). Decomposition is usually carried out by heating the volatile carbonyl to over 180°C, preferably at a low partial pressure of carbon monoxide. The decomposition of volatile carbonyls can be performed either as a mixture of nickel and cobalt carbonyls or after separating the two compounds. Decomposition can also be carried out by converting volatile carbonyls into nickel and / or cobalt sulfates by reaction with H2SO4. This can be accomplished by dissolving metallic nickel and / or cobalt or intermediate oxides. Step (4.2.) optionally consists of purifying the nickel and / or cobalt, for example, by hydrometallurgical processes or electrorefining. Preferably, the required metal purity is achieved without step (4.2). Other compounds can be recovered from the process of the invention: A lithium salt obtained as an aqueous solution from steps (1.3) or (3.5) can be recovered by evaporating the water and crystallizing the lithium salt. It can be transformed into another lithium salt, for example, by precipitation or decomposition. The solid carbonylation residue obtained from steps (2.1) can be introduced into a smelter to recover mainly copper and iron; or it can be subjected to a hydrometallurgical treatment from which the metals can be obtained in the form of metallic salt solutions that can be subjected to other separation and purification steps such as precipitation, solvent extraction and / or electrorefining. Through hydrometallurgical treatment, solid carbonaceous materials (e.g., graphite) can be isolated, purified, and used for the production of electrodes for electrochemical processes or batteries. The invention offers several advantages: The present invention allows for the recovery of valuable nickel and cobalt metals from batteries. It avoids hydrometallurgical steps that require large quantities of acids and bases and frequent solid-liquid separation steps. The transformation of the nickel and cobalt constituents of the batteries into volatile carbonyls is highly selective, resulting in the formation of only iron carbonyls, which can be easily separated, for example, by distillation. Copper impurities, in particular, can be easily removed. EXAMPLES Description of the methods: Elemental compositions were determined by elemental analysis using ICP-OES (inductively coupled plasma optical emission spectroscopy) or ICP-MS (inductively coupled plasma mass spectrometry). Phase analysis was performed by powder X-ray diffraction (PXRD). Abbreviations: In the context of the present invention, normal pressure means 1 atm or 1013 mbar. “Normal conditions” means normal pressure and 20°C. NI means normal liter, liter under normal conditions (1 atm, 20°C). Percentages refer to % by weight, unless specifically defined otherwise. The expressions % by weight and % wt may be used interchangeably. Whenever mentioned, the expressions “ambient temperature” and “ambient temperature” denote a temperature between approximately 18 and 25°C. XRD means powder X-ray research (typically Cu k-alpha1 radiation of 154 pm or Mo k-alpha1 radiation of 71 pm). Example 1: Heating the synthetic product sample A quantity of 200g of simulated spent battery scrap containing 78.8 g of spent cathode active material containing nickel, cobalt and manganese in similar molar amounts, approximate formula Li(Ni0.34Co0.33Mn0.33)02, 62.2 g of carbon in the form of graphite and soot 47.0 g of organic electrolyte mixture (containing LÍPF6) 7.4 g of polyvinylidene fluoride as a binder 2.4 g of aluminum powder, 0.2 g of iron powder, 2.0 g of metallic copper is introduced into a 500 mL quartz round-bottom flask and attached to a rotating evaporator so that the flask is immersed in a furnace. The rotating flask is heated to 800°C over 4.5 hours, with the heating occurring over 2 hours under an argon flow (20 L / h) and the temperature maintained for 1 hour under a dry air flow (20 L / h) before being cooled to room temperature. A quantity of 173.3 g of heat-treated material is obtained, comprising a composition of Ni / Co alloy, iron-manganese oxide, and graphite phases. Example 1a: Heating of lithium-ion batteries A quantity of ~1 t of mechanically 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 other impurities comprising, among other things, fluorine, phosphorus and calcium compounds, is treated to obtain a reduced mass according to the process described in Jia Li et al., Journal of Hazardous Materials 302 (2016) 97-104. The atmosphere inside the roasting system is air whose oxygen reacts with the carbon in the battery scrap to form carbon monoxide; the treatment temperature is 800°C. After the reaction and cooling to room temperature, the heat-treated material is recovered from the furnace, mechanically treated to obtain a particulate material, and analyzed by X-ray diffraction and elemental analysis. The Ni and Co content is determined to be 17.7 and 17.5% by weight, respectively, which serve as a reference for all subsequent carbonylation examples (see below). Comparing the XRD patterns before and after heat treatment with the calculated reference patterns of Li(Ni,Co,Mn)O2, Ni (which is identical to that of CoxNi1-x, x = 0-0.6) and Co, it can be concluded that the active cathode material is completely decomposed and that Ni and Co are present exclusively as metallic phases, either as pure Ni or as an alloy in combination with Co. The presence of metallic nickel and cobalt is supported by the qualitative observation that the entire sample exhibits typical ferromagnetic behavior when in contact with a permanent magnetic material. Example 2: Carbonylation of a synthetic product sample with CO and H2 One gram of a 50 / 50 mixture of Co and Ni powder is introduced into an autoclave and reacted with CO and H2 at 170°C and 200 bar. The respective gas flow rates are 15 Nl / h for CO and H2. After 10 hours of reaction, the autoclave is purged with nitrogen and cooled. The solid residue is isolated, weighed (0.5 g), and its Ni and Co content is analyzed (Ni: 3% by weight, Co: 96% by weight), resulting in Ni and Co recoveries of 97% and 4%, respectively, from the volatiles. Example 2a: Carbonylation of the reduced material with CO and H2 at 170°C / 200 bar An autoclave is filled with 1 g of the previously mentioned reduced battery scrap material (obtained as shown in Example 1a, Ni content 17.7%, Co content 17.5%) and reacted with CO and H2 at 170°C and 200 bar. The respective gas flow rates are 15 Nl / h for CO and H2. After 10 hours of reaction, the autoclave is purged with nitrogen and cooled. The solid residue is isolated, weighed (0.88 g), and its Ni and Co content is analyzed (Ni: 15.4 wt%, Co: 16.1 wt%), resulting in Ni and Co recoveries from the volatiles of 23% and 19%, respectively. Example 2b: Carbonylation of the reduced material with CO and H2 at 200°C / 200 bar Example 2a is repeated applying 200°C and 200 bar; all other experimental conditions are kept constant. 0.88 g of solid residue is isolated and its Ni and Co content is analyzed (Ni: 16.5 wt%, Co: 17.2 wt%), which represents a recovery of Ni and Co of 18 and 14%, respectively. Example 3: Carbonylation of a suspension of Ni powder in dodecane with CO One g of nickel powder is mixed with 70 mL of dodecane, placed in a stirred autoclave, and reacted with 15 NI of CO at 150°C and 200 bar for 8 h; this procedure is performed twice. After these two reactions, the autoclave is purged with nitrogen, cooled, and opened. IVIA / a / ZUZZ / UI 1 fül observes that there is almost no nickel powder left, concluding that the carbonylation reaction and evaporation have been successfully completed. Example 3a: Carbonylation of a suspension of Co powder in dodecane with CO and H2 One gram of cobalt powder is mixed with 70 mL of dodecane, placed in a stirred autoclave, and reacted with 15 NI of CO and H2, respectively, at 170°C and 200 bar for 8 h. To capture the volatile cobalt carbonite species, the gas flow is passed through a 10% NaOH solution. This solution is analyzed for its cobalt content and used to quantify the cobalt recovery, which is 1%. After the reaction, the autoclave is purged with nitrogen, cooled, and opened. Example 3b: Carbonylation of a suspension of the dodecane-reduced material with CO and H2 0.5 g of the previously mentioned reduced battery material (obtained as shown in Example 1a, Ni content 17.7%, Co content 17.5%) is mixed with 70 mL of dodecane, placed in a stirred autoclave, and reacted with CO and H₂ under different experimental conditions (see Table 1). To capture the volatile Co carbonite species, the gas flow is passed through a 10% NaOH solution. This solution is analyzed for its Co content and used to quantify the Co recovery. The solution is not replaced between experiments. The results are also summarized in Table 1. ινΐΛ / a / zuzz / uii / yi Table 1 Exp. No. 2 Temperature [°C] Pressure [bar] Gas Flow [N] Duration [h] Co Concentration [ppm] Solution Volume [mL] Co Recovery [%] CO H2 1 110 100 15 0 4 0 160 0 2 110 200 15 15 4 8 160 1.5 3 130 100 15 0 4 nd 150 4 130 200 15 15 3 80 150 13.7 5 80 50 15 0 3 nd 140 6 170 200 15 15 3 210 118 28.3

Claims

1. A process for recovering transition metals from battery materials comprising (0.1) providing a battery material comprising nickel oxide and / or cobalt compounds, (1.1) heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt, (2.1) carbonylating the reduced material with carbon monoxide, optionally in the presence of a reactive gas, to produce a solid carbonylation residue and a volatile carbonyl comprising compounds containing nickel and / or cobalt carbonyl, and (3.1) separating the volatile carbonyl from the solid carbonylation residue by evaporation.

2. The process according to claim 1, wherein the battery materials are lithium-ion battery materials.

3. The process according to claim 1 or 2, wherein the battery material comprises complete batteries, mechanically treated waste batteries, or battery scrap or waste from the production of batteries or battery components.

4. The process according to any of claims 1 to 3, wherein the battery material contains between 1 and 30% by weight, preferably between 3 and 25% by weight, and in particular between 8 and 16% by weight of nickel oxide compounds.

5. The process according to any of claims 1 to 3, wherein the battery material contains between 1 and 30% by weight, preferably between 3 and 25% by weight, and in particular between 8 and 16% by weight of cobalt compounds.

6. The process according to any of claims 1 to 5, wherein step (1.1) is performed by heating the battery material in an inert atmosphere of hydrogen or oxygen.

7. The process according to any of claims 1 to 6, wherein the carbonylation is carried out at a temperature of 30 to 300°C and a partial pressure of 1 to 300 bar.

8. The process according to any of claims 1 to 7, wherein the volatile carbonyl comprises Ni(CO)4, HCo(CO)4 and / or (NO)Co(CO)3.

9. The process according to any of claims 1 to 8, wherein, in addition to carbon monoxide, an inert gas and / or a reactive gas is present during carbonylation.

10. The process according to claim 9, wherein the inert gas is nitrogen, argon or carbon dioxide.

11. The process according to claim 9, wherein the reactive gas is hydrogen or nitric oxide.

12. The process according to any of claims 1 to 11, wherein a carbonylation catalyst selected from ammonia, sulfur, or sulfur compounds is present during the carbonylation.

13. The process according to any of claims 1 to 12, wherein nickel and cobalt are present in the reduced material and the reduced material is first carbonized in the absence of a reactive gas to produce a volatile nickel carbonyl, and then in the presence of a reactive gas to produce a volatile cobalt carbonyl, or vice versa.

14. The process according to any of claims 1 to 13 further comprises (4.1) decomposing the volatile carbonyl to produce nickel and / or cobalt in elemental form or as salts.

15. The process according to any one of claims 1 to 14, comprising at least one of the following steps (0.2), (0.3), (0.4), (0.5), (1.2), (1.3), (3.2), (3.3), (3.4), (3.5) and (4.2): (0.1) providing a battery material comprising nickel oxide and / or cobalt compounds, (0.2) optionally washing the battery material with an organic solvent to remove the organic electrolyte and polymeric binder, (0.3) optionally washing the battery material with an aqueous medium, (0.4) optionally subjecting the battery material to solid-solid separation, such as flotation, electroclassification, sieving or magnetic separation, to remove solids, such as carbon, polymers or magnetic material, (0.5) optionally heating the battery material to 350°C to evaporate the organic components of the electrolyte, (1.(1) heating the battery material above 350°C to produce a reduced material containing elemental nickel and / or cobalt, (1.2) optionally, subjecting the reduced material to a solid-dry separation, such as electroclassification, sieving or magnetic separation, to remove solids, such as carbon, polymers or magnetic material, (1.3) optionally, treating the reduced material with an aqueous medium, optionally acidic, to produce a suspension containing a dissolved lithium salt and undissolved material, optionally, subjecting the suspension to a solid-liquid separation to separate the dissolved lithium salt from the undissolved material, and optionally, subjecting the undissolved material to a solid-solid separation to remove solids, such as carbon, polymers, magnetic material or undissolved lithium salts, (2.(3.1) carbonylating the reduced material with carbon monoxide, optionally in the presence of a reactive gas, at a temperature of 30 to 300°C and a partial pressure of 1 to 300 bar, to produce a solid carbonylation residue and a volatile carbonyl comprising compounds containing nickel and / or cobalt carbonyl, (3.2) separating the volatile carbonyl from the solid carbonylation residue by evaporation, (3.3) optionally purifying the separated volatile carbonyl by adsorption, condensation, distillation or vaporization, (3.4) optionally decomposing a non-volatile metal carbonyl in the solid carbonylation residue, (3.5) optionally subjecting the solid carbonylation residue to a solid-dry separation, such as electroclassification, sieving or magnetic separation, to remove solids such as carbon, polymers or magnetic material, (3.5) optionally, treating the solid carbonylation residue with an optionally acidic aqueous medium to produce a suspension containing a dissolved lithium salt and undissolved material; optionally, subjecting the suspension to solid-liquid separation to separate the dissolved lithium salt from the undissolved material and, optionally, subjecting the undissolved material to solid-solid separation to remove solids such as carbon, polymers, magnetic material or undissolved lithium salts, (4.1) optionally, decomposing the volatile carbonyl to produce nickel and / or cobalt in elemental form or as salts, and (4.2) optionally, further purifying the nickel and / or cobalt.