PROCESS FOR PREPARING NICKEL, MANGANESE AND / OR COBALT HYDROXIDES

Abstract

This invention relates to a process for preparing a mixture comprising at least one valuable metallic compound selected from nickel, manganese, and cobalt hydroxides, from a raw material comprising at least one valuable metallic compound and at least one undesirable metallic compound, the process comprising the following steps: - E1: transformation of at least one valuable metallic compound and at least one undesirable metallic compound into the corresponding chloride complexes in an aqueous solution; - E2: selective separation of at least one undesirable metallic complex from at least one valuable metallic complex to obtain an intermediate solution free of undesirable metal complexes; - E3: addition of a sodium hydroxide solution to the intermediate solution to precipitate at least one valuable metallic complex in the form of the corresponding hydroxide compound in a final solution;and - E4: filtration of the final solution to obtain a powder of at least one valuable metallic hydroxide and a sodium chloride solution. Fig. 1;

Description

Title of the invention: METHOD FOR PREPARING NICKEL, MANGANESE AND / OR COBALT HYDROXIDES Scope of the invention

[0001] The invention relates to a process for preparing a mixture comprising at least one valuable metal selected from nickel, manganese and cobalt in the form of hydroxides, from an initial raw material comprising impurities and / or undesirable metals in addition to at least one valuable metal. State of the art

[0002] Lithium-ion batteries are used worldwide in numerous devices such as electronic appliances, wireless devices, portable power tools, electric vehicles such as electric cars, scooters and bicycles, and the like. The increasing use of these devices and vehicles makes battery manufacturing a major challenge.

[0003] Some lithium-ion batteries commonly include a combination of nickel, manganese, and cobalt, known as NMC materials. The proportion of these three metals can vary depending on the type of battery. A common process for preparing these batteries involves using pure nickel, manganese, and / or cobalt compounds.

[0004] The preparation of pure nickel, manganese, and / or cobalt compounds usually involves industrial processes using, as raw material, a mixture comprising at least one of the following nickel, manganese, and cobalt compounds, as well as impurities that must be removed. Usable raw materials may, for example, come from natural mines or from recycled materials from the lithium-ion battery chain (e.g., CAM, pCAM, or black mass, CAM being defined as a cathode active material).

[0005] However, these industrial processes can use large quantities of chemicals and / or generate waste that is difficult to recycle. Furthermore, these processes can involve a large number of steps and can be costly and consume significant time and energy.

[0006] There is therefore still a need to improve industrial processes for preparing nickel, manganese and / or cobalt compounds. Description of the invention

[0007] An object of the invention is therefore to make available a process for preparing nickel, manganese and / or cobalt compounds while limiting the use of chemicals, the disposal of waste and / or the number of steps.

[0008] To this end, an object of the invention is a process for preparing a mixture comprising at least one valuable metallic compound selected from nickel, manganese and cobalt hydroxides, from a raw material comprising at least one valuable metal compound and at least one undesirable metal compound, the process comprising the following steps: - El: transformation of at least one valuable metallic compound and at least one undesirable metallic compound into the corresponding chloride complex(s) in an aqueous solution; - E2: selective separation of at least one undesirable metal complex from at least one valuable metal complex to obtain an intermediate solution free of undesirable metal complexes; - E3: addition of a sodium hydroxide solution to the intermediate solution to precipitate at least one valuable metal in the form of the corresponding hydroxide compound(s) in a final solution; and - E4: filtration of the final solution to obtain a powder of at least one valuable metallic hydroxide and a sodium chloride solution.

[0009] This process makes it possible to prepare nickel, manganese or cobalt hydroxide, or a mixture of two or three of these hydroxides, using a raw material, usually solid, containing a compound of nickel, cobalt or manganese, or a mixture of two or three of these compounds, without separating one of these metals from the others during the process.

[0010] Furthermore, the formation in step El of metal chloride complexes and the subsequent precipitation of metal complexes using sodium hydroxide allows the obtaining of a sodium chloride solution, which is a non-toxic and easily recyclable salt. Raw material

[0011] The raw material can come from extractions in natural mines or from recycling processes, in particular battery recycling.

[0012] The raw material may comprise only a nickel compound, or only a manganese compound, or only a cobalt compound, or may comprise two or three compounds selected from nickel, manganese and cobalt compounds, usually in the form of hydroxides.

[0013] When the raw material comprises two or three compounds among the nickel, manganese and cobalt compounds that are valuable compounds, these same two or three compounds are recovered in powder form in step E4. Furthermore, the proportion of these two or three compounds in the raw material can be maintained during the process since the nickel, manganese and cobalt are not separated during the process, and none of the compounds are lost during the process. This means that the amount of each of nickel, manganese and / or cobalt that may be lost at the end of each step of the process may be less than 5% by weight relative to the weight of the corresponding compounds at the beginning of each step.

[0014] In the raw material, nickel, manganese, and cobalt are in their oxidized form or in their metallic form, i.e., nickel(O), manganese(O), and / or cobalt(O). In their oxidized form, the metal, i.e., nickel, manganese, or cobalt, is the central cation and is surrounded by ligands, a ligand being a neutral molecule or an ion.

[0015] In the present description, when nickel, manganese, and cobalt are solid, whether in their oxidized or metallic form, they are referred to as "metallic compounds," "nickel compound," "manganese compound," and "cobalt compound." Furthermore, when nickel, manganese, and cobalt are solubilized in a solution, they exist as a coordination complex, and are then referred to as "metallic complexes," "nickel complexes," "manganese complexes," and "cobalt complexes."

[0016] In the raw material, when nickel, manganese, and cobalt are in their oxidized form, their oxidized forms may be of the same type or of different types; that is, the ligand(s) surrounding each valuable metal may be identical or different from the ligand surrounding the other valuable metal(s). Preferably, the oxidized forms of nickel, manganese, and cobalt are of the same type.

[0017] The raw material may include different oxidized forms of the same valuable metal, for example Mn(OH)2 and MnO2.

[0018] The ligand surrounding nickel, manganese and / or cobalt in the raw material can be chosen from the following ligands: hydroxide, chloride, sulfate, oxide, sulfide, carboxylate, carbonate, dihydrogen phosphate, nitrate, hydrogen phosphate, bicarbonate, acetate, and a mixture of these ligands.

[0019] Preferably, when the raw material comprises two or three of the compounds of nickel, manganese and cobalt, the compounds are of the same type and are in the form of metal hydroxides, that is to say that each of the nickel, manganese and / or cobalt is surrounded by hydroxide ligands.

[0020] The quantity of each of the nickel, manganese, and cobalt compounds in the raw material can be in the range of 0% to 95% by mass relative to the total mass of the raw material, preferably from 3% to 70% by mass relative to the total mass of the raw material. For example, the quantity of one of the nickel, manganese, and cobalt compounds can be at least 20% by mass relative to the total mass of the raw material, while the quantity of the other two valuable compounds can be in the range of 0% to 80% by mass relative to the total mass of the raw material.

[0021] The raw material further comprises at least one undesirable metal, in particular a metal selected from aluminium (Al), copper (Cu), iron (Fe), zinc (Zn), chromium (Cr), calcium (Ca), scandium (Sc), and one of their mixtures.

[0022] In the present description, an undesirable metal is a metal that is present in the raw material and is not desired in the final solution.

[0023] Undesirable metals do not include any nickel, manganese and cobalt.

[0024] In the present description, when an unwanted metal is solid, i.e. in its oxidized or metallic form, it is called a "metallic compound". Furthermore, when an unwanted metal is in solution in the form of a coordination complex, it is called a "metallic complex".

[0025] When the raw material includes several undesirable metals in their oxidized form, their oxidized forms may be of the same type or of different types, that is to say that the ligand(s) surrounding each undesirable metal may be identical or different from the ligand surrounding the other valuable metal(s).

[0026] When an undesirable metal is in its oxidized form in the raw material, the ligand(s) can be chosen from among the hydroxide, chloride, sulfate, oxide, sulfide, carboxylate, carbonate, dihydrogen phosphate, nitrate, hydrogen phosphate, bicarbonate, acetate, and a mixture of these ligands.

[0027] The raw material may include different oxidized forms of the same undesirable metal.

[0028] The quantity of each of the undesirable metals in the raw material may be the same or different and may be in the range of 0.05% to 40% by mass relative to the total mass of the raw material, preferably 0.10% to 20% by mass relative to the total mass of the raw material.

[0029] The raw material may also include impurities which may be any compound not comprising metal, in particular organic compounds, and for example sulfur compounds, sulfide compounds, sulfate compounds, graphite, fluoride compounds, phosphate compounds, and the like.

[0030] The quantity of each impurity in the raw material may be less than 50% by mass relative to the total mass of the raw material, preferably less than 30% by mass relative to the total mass of the raw material, and more preferably less than 7% by mass relative to the total mass of the raw material.

[0031] In addition, the total quantity of all impurities in the raw material may be less than 60% by mass relative to the total mass of the raw material, preferably less than 40% by mass relative to the total mass of the raw material, and more preferably less than 10% by mass relative to the total mass of the raw material.

[0032] The raw material may further include water, the water content being for example in the range of 0% to 80% by mass relative to the total mass of the raw material, preferably from 5% to 60% by mass relative to the total mass of the raw material. Stage El

[0033] In step El, the valuable metal(s) and the undesirable metal(s) are transformed into their chloride complexes in an aqueous solution.

[0034] Step El can be carried out using a reagent chosen from hydrochloric acid, sodium hypochlorite, chlorine gas, and one of their mixtures.

[0035] According to a first embodiment, step E1 can be carried out using hydrochloric acid, in particular an aqueous solution of hydrochloric acid. According to a variant of this embodiment, the raw material can be placed in water and then the aqueous hydrochloric acid solution can be added. According to another variant of this embodiment, the raw material can be placed directly in an aqueous hydrochloric acid solution.

[0036] According to a second embodiment, step E1 can be carried out using sodium hypochlorite. According to one variant of this embodiment, the raw material can be placed in water and then the sodium hypochlorite can be added. According to another variant of this embodiment, the raw material can be placed directly in an aqueous solution of sodium hypochlorite.

[0037] According to a third embodiment, step El can be carried out using gaseous chloride. According to this embodiment, step El is carried out by bubbling gaseous chlorine into an aqueous solution of crude material.

[0038] According to the three possible embodiments, step El is carried out at a pH value in the range of 0.1 to 4, preferably from 0.1 to 3, and more preferably from 0.1 to 2. The pH value during step El can be, for example, 1.

[0039] The raw material, which is usually solid, can be crushed into a powder before the implementation of step EL

[0040] Step EL, which is a leaching step, allows the transformation of one or more valuable and undesirable metals into chloride complexes. These chloride complexes are soluble in the aqueous solution obtained at the end of step EL.

[0041] Step El can be carried out at a temperature in the range of 5°C to 95°C, preferably from 30°C to 90°C, and more preferably from 50°C to 90°C. The leaching step is, for example, carried out at a temperature of 80°C.

[0042] According to one embodiment, the raw material may include one or more valuable metals and / or undesirable metals in an oxidation state which must be modified, in particular so that the corresponding compound(s) are made soluble in the aqueous solution of step EL. The oxidation state can therefore be modified during step EL by the addition of a reducing or oxidizing agent.

[0043] The reducing agent may for example be a peroxide such as hydrogen peroxide, sodium sulfite, sodium dithionite, sodium thiosulfate, ascorbic acid, citric acid, and the like.

[0044] The oxidizing agent can, for example, be chlorine gas, sodium hypochlorite, bleach.

[0045] The reducing agent can be added in an amount sufficient to bring the aqueous solution of step El to an oxidation / reduction potential (redox potential) that allows the transformation of all metal complexes into soluble complexes. According to this embodiment, the aqueous solution of step El is brought to a redox potential in the range of 0 millivolts (mV) Ag / AgCl to 1200 mV Ag / AgCl, preferably from 300 mV Ag / AgCl to 1000 mV Ag / AgCl.

[0046] Valuable metallic compounds which must be reduced may be, for example, manganese oxides such as MnO2 and Mn3O4, cobalt oxides such as CoO2, Co3O4, cobalt hydroxide such as Co(OH)3.

[0047] According to one possible embodiment, during step E1, a certain quantity of nickel, manganese, and / or cobalt can be added to adjust the Ni / Mn / Co ratio and obtain the appropriate ratio in the prepared mixture, i.e., the final solution contains at least one of nickel, manganese, and cobalt. The addition of nickel, manganese, and / or cobalt can be carried out by adding a corresponding chloride complex or any compound that will be transformed into a chloride complex during step E1, such as those already listed with regard to the raw material. Preferably, the valuable metallic compounds added can be in the form of a hydroxide or carbonate complex. Step E2

[0048] Step E2 aims to separate impurities and any undesirable metals from valuable metals to obtain a composition free from impurities and undesirable metals.

[0049] In the present description, the expression "free from" in relation to a compound, i.e. a valuable metal, an impurity or an undesirable metal, refers to the amount of that compound in a solution, and means that said solution comprises less than 100 mg / l, preferably less than 5 mg / l, and more preferably less than 1 mg / l, of said compound.

[0050] In particular, this step involves a reaction that transforms the valuable metal complexes and / or the undesirable metal complexes so that the valuable metal complexes and the undesirable metal complexes exhibit different behavior in a reaction medium. Different behavior includes different solubility depending on the pH of a solution, different solubility depending on the redox potential of a solution, and different separation coefficients in a mixture of two immiscible solvents.

[0051] Advantageously, in the case where the aqueous solution comprises two or three valuable metals, the separation process is chosen so that, during and at the end of the separation, the valuable metals have the same behavior and are kept together.

[0052] Therefore, step E2 may include at least one method selected from hydrolysis to obtain a specific pH; modification of the redox potential of the solution; filtration; solvent separation, in particular by an organic solvent; cementation on a metal powder; separation by ion exchange; or a combination of two or more of these methods.

[0053] According to one embodiment, step E2 may include hydrolysis, which may be basic or acidic, and which may transform the valuable metal(s) and / or the undesirable metal(s) to obtain a difference in solubility between the valuable and undesirable metal(s) at a predetermined pH. According to this embodiment, filtration may be carried out to separate the valuable and / or undesirable metal(s) after the hydrolysis step.

[0054] According to a preferred embodiment, step E2 may include a basic hydrolysis using a base selected from sodium hydroxide (NaOH), sodium carbonate (Na2CO3); cobalt hydroxide (Co(OH)2), Ni(OH)2, Mn(OH)2, or a mixture of at least two of them; sodium bicarbonate (NaHCO3); and any mixture thereof. Preferably, the base used for the basic hydrolysis may be sodium carbonate (Na2CO3) or sodium hydroxide (NaOH).

[0055] When basic hydrolysis is carried out, the undesirable metal complexes are transformed into a corresponding insoluble compound, while the valuable metal(s) remain soluble in the form of chloride complexes. Advantageously, the pH is chosen so that the chloride complexes of the valuable metal(s) are not hydrolyzed and remain soluble in the aqueous solution in their chloride form, while the undesirable metal compounds are not soluble.

[0056] In particular, during basic hydrolysis, the aqueous mixture may have a pH in the range of 1.5 to 7, preferably 2 to 6, and more preferably 3 to 5. For example, basic hydrolysis in step E2 is carried out at a pH of 4.

[0057] Certain hydroxide complexes such as aluminium (Al), copper (Cu), iron (Fe), zinc (Zn), chromium (Cr), calcium (Ca), scandium (Sc), and any mixture thereof, may precipitate at the aforementioned pH.

[0058] According to this preferred embodiment, basic hydrolysis can be carried out at a temperature in the range of 20°C to 95°C, preferably from 30°C to 90°C, and more preferably from 50°C to 90°C.

[0059] As a first example of step E2, hydrolysis using sodium hydroxide can be carried out during step E2 to transform the unwanted metal(s) into a hydroxide complex, while the pH is maintained at a value at which the unwanted metal hydroxides precipitate and the valuable metal(s) remain soluble as a chloride complex. Filtration then separates the unwanted metal hydroxides from the valuable metal chlorides.

[0060] According to a second example of step E2, step E2 may include extraction with an extracting solvent that forms an organic complex with the unwanted metal(s), so that the unwanted metal(s) are then separated from the aqueous solution by an extraction step with an organic solvent. Such a solvent may be, for example, a phosphorus-containing organic solvent, in particular an organophosphorus acid such as di(2-ethylhexyl)phosphoric acid, bis(2,4,4-trimethylpentyl)phosphinic acid, mono-2-ethylhexyl (2-ethylhexyl)phosphonate, tributyl phosphate, a trialkylphosphine oxide; a carboxylic acid; an aliphatic amine; or a mixture thereof.

[0061] According to a third example of step E2, step E2 may include basic hydrolysis according to the first example, followed by solvent extraction according to the second example, or solvent extraction according to the second example followed by basic hydrolysis according to the first example.

[0062] According to one possible variant of a basic hydrolysis, oxygen can be added to the aqueous solution during the hydrolysis. The oxygen can be added by introducing pure dioxygen (O2) or from air. Such an oxidizing condition can allow the oxidation of unwanted metals such as iron(II) to iron(III), which is then hydrolyzed to yield the corresponding hydroxide complex.

[0063] The process may also include an additional purification step A1 using an activated carbon filter. This step should allow the trapping of impurities and contaminants such as volatile organic compounds and potential contaminants by the porous structure of the activated carbon. Step E3

[0064] After step E2, an aqueous solution, called the intermediate solution, comprising one or more valuable metals in the form of the chloride complex, i.e. NiCl2, MnCl2 and / or CoCl2, and free from impurities and any undesirable metals, is obtained.

[0065] In step E3, sodium hydroxide is added to the intermediate solution at a pH enabling the hydrolysis of the valuable metal chloride complex(s) into the corresponding solid hydroxide compounds, i.e. Ni(OH)2, Mn(OH)2 and / or Co(OH)2. At this step, at least 70%, preferably at least 85%, of each of the valuable metal chloride complex(s) are hydrolyzed into the corresponding solid hydroxide compounds.

[0066] This precipitation step E3 can be carried out at a pH in the range of 6 to 10, preferably 6 to 8, and especially 6 to 7.

[0067] As a by-product, this precipitation step forms a sodium chloride solution. Step E4

[0068] The mixture comprising nickel, manganese and / or cobalt hydroxides and sodium chloride is then filtered in step E4 to obtain a mixture of solid nickel, manganese and / or cobalt hydroxides and a sodium chloride filtrate solution.

[0069] The mixture of solid nickel, manganese and / or cobalt hydroxides can then be washed and dried to obtain a powder of solid nickel, manganese and / or cobalt hydroxides free from undesirable compounds.

[0070] This final solid may be present with various proportions of nickel, manganese and / or cobalt depending on their proportion in the raw material and the possible addition of one or more nickel, manganese and cobalt compounds during the process.

[0071] In addition, the final solid may be free of undesirable metal, i.e. metals other than nickel, manganese and cobalt, and impurities.

[0072] According to one possible embodiment, an adjustment step can be carried out before step E3 to modify the proportion of nickel, manganese and cobalt, in particular by adding one or more of these metals in the form of a complex, preferably a chloride complex. Step E5

[0073] The process may also include a step E5 during which electrolysis is carried out with the sodium chloride solution obtained in step E4. This electrolysis allows obtaining a solution containing sodium hydroxide, chlorine and gaseous dihydrogen.

[0074] Chlorine and hydrogen gas are then used in a combustion process to produce hydrogen chloride gas. The hydrogen chloride gas is trapped with water to produce hydrochloric acid. Step E6

[0075] The process may also include a step E6 comprising the use of hydrochloric acid or chlorine gas prepared in step E5 to carry out another leaching step in step EL

[0076] Furthermore, the sodium hydroxide obtained in step E5 can be used to carry out another precipitation step E3.

[0077] Steps E4 and E5 therefore make it possible to prepare hydrochloric acid and sodium hydroxide from sodium chloride and limit the waste of sodium chloride and also the use of commercial sodium hydroxide and / or hydrochloric acid. Description of the Figures

[0078] [Fig.1] shows the steps of an illustrative process according to the invention. Example

[0079] In this example, the raw material is a mixed hydroxide precipitate (MHP) comprising nickel, manganese, and cobalt in the form of hydroxide compounds, impurities, and unwanted metals. This example aims to prepare a pCAM product useful for battery manufacturing.

[0080] During the process, the resulting mixture can be analyzed by inductively coupled plasma spectroscopy (ICP), Auger electron spectroscopy (AES), inductively coupled plasma spectroscopy (ICP) combined with mass spectrometry, or X-ray diffraction (XRD) analysis. MHP is an intermediate product derived from the hydrometallurgical treatment of nickel ore. The raw material has a composition comprising at least what is shown in Table 1 below. [Tables 1] Element % by mass Compounds M by mass Ni 40.2 Ca 0.45 Co 2.92 Zn 0.661 Mn 4 Cr 0.08 Al 0.22 Na 0.06 Cu 0.19 S 5 Fe 0.09

[0081] The leaching step El is implemented by using 1.5 kg of raw material in a mixture of 0.8 l of water, 1.2 l of 35% hydrochloric acid by weight, and 0.15 l of 35% hydrogen peroxide by weight serving as a reducing agent.

[0082] The pH of the mixture is 1 and the mixture is stirred for 5h40 at a temperature of 80°C.

[0083] This step allows the reduction of Mn(IV) to Mn(II) and of Fe(III) to Fe(II) and also the transformation of all hydroxide complexes into corresponding chloride complexes, in particular the chlorides of valuable metals and the chlorides of undesirable metals, with a yield of at least 95%, preferably 99%. An acidic mixture S1 is obtained.

[0084] In step E2, the acidic mixture SI then undergoes a basic hydrolysis (Hl) using Na(OH)2 as a base with the addition of dioxygen from ambient air. This hydrolysis step is carried out at a pH of 4, at a temperature of 80°C, and for 2 hours.

[0085] During this step, nickel, manganese, and cobalt remain in the form of their chloride complex, and the unwanted metals are transformed into their hydroxide complex. Furthermore, FeCl2 is oxidized to its oxidation state III and then hydrolyzed to Fe(OH)3.

[0086] At the end of the basic hydrolysis, a mixture S2 is obtained in which the majority of the Fe(OH)3, A1(OH)3 and Cr(OH)3 complexes precipitate and are removed by filtration (Fl) while the NiCl2, MnCl2, CoCl2 and ZnCl2 complexes remain soluble in the filtrate solution S3.

[0087] Still in step E2, the filtrate solution S3 then undergoes a separation step (Extl), which is a purification by extraction using DEHPA as an extraction agent in an aromatic solvent. In this example, the aromatic solvent is a naphtha solvent marketed under the reference Solvesso 100, which is a C9 aromatic solvent.

[0088] This additional extraction step comprises four substeps: saponification of the extraction agent, an extraction substep, a purification substep, and a gas extraction substep. Each substep comprises four extraction phases, six purification phases, and four gas extraction phases.

[0089] The saponification substep is carried out on a DEHPA solution in a naphtha solvent, to which an aqueous sodium hydroxide solution is added to convert DEHPA-H+ to DEHPA-Na+. The saponified DEHPA-Na+ extraction agent is in the organic phase and is used in the extraction substep.

[0090] During the extraction substep, the filtrate solution S3 is contacted with DEHPA-Na+ in the organic phase mixture. An ion-exchange reaction occurs between sodium and certain metals in the filtrate solution S3 to obtain metal complexes with DEHPA in the organic phase. In particular, DEHPA-Zn2+ and DEHPA-Ca2+ are formed in high yield, at least 95%, and DEPHA-Mn2+ is also formed at a rate of approximately 6%. The following complexes are also formed at a low rate of less than 2%: DEPHA-Ni2+ and DEPHA-Co2+. Consequently, during this extraction step, nickel and cobalt remain mainly in the aqueous phase in the form of their chloride complexes.

[0091] An aqueous solution S4 free from most undesirable metals is obtained after extraction.

[0092] For the recovery of valuable metals nickel, manganese and cobalt inevitably extracted, the organic phase is washed with a dilute solution of hydrochloric acid having a pH of 1 to 2.

[0093] A gas extraction phase can also be carried out with hydrochloric acid having a pH of 0 to 1 to remove all metals from the organic phase and recycle the DEHPA organic phase to the saponification substep. The acidic aqueous phase from the gas extraction substep contains all the extracted impurities and unwanted metals and is sent to a disposal step.

[0094] The aqueous solution S4 comprising NiCl2, MnCl2 and CoCl2 is filtered (step F2) on an activated carbon cartridge so that organic contaminants, in particular organic compounds, are captured by the porous carbon structure.

[0095] The filtered aqueous solution S5 comprises NiCl2, MnCl2 and CoCl2 and only a few remaining undesirable metals such as magnesium, and some impurities.

[0096] If necessary, in order to obtain the correct proportion (or molar stoichiometry) of nickel, manganese and cobalt, i.e. 8 / 1 / 1, an adjustment step can be carried out by adding suitable quantities of pure NiCl2, MnCl2 and / or CoCl2 to the S5 solution.

[0097] Step E3 is now carried out on the filtered aqueous solution S5 for the precipitation of NiCl2, MnCl2 and CoCl2 as insoluble hydroxide compounds by adding a sodium hydroxide (NaOH) solution to solution S5 to achieve a pH between 6 and 6.5. At this pH, at least 95% of Each of the nickel, cobalt, and manganese precipitates in its insoluble hydroxide form. The resulting paste S6, comprising Ni(OH)2, Mn(OH)2, and Co(OH)2, is filtered in step E4, and the filter cake (PI) is washed (Wl) and represents the final product (FP). The final product is dried and packaged for sale.

[0098] The filtrate from step E4 still contains certain metals, traces of nickel, manganese, and cobalt. These metals are precipitated by the addition of Na₂CO₃ at a pH of 10. The metals form compounds in the form of insoluble carbonates. The resulting paste is filtered. The solid phase is rejected from the process, and the filtrate S7, containing mainly NaCl, is sent to step E5.

[0099] The filtrate S7 is then purified (PI) according to a known process capable of undergoing electrolysis, for example reverse osmosis, removal of trace metals by ion exchange, or similar methods. The resulting solution is called S8.

[0100] In step E5, electrolysis is carried out on the solution S8, which allows obtaining a solution containing sodium hydroxide, chlorine and gaseous dihydrogen.

[0101] Chlorine and gaseous dihydrogen are then used in a combustion process to produce hydrochloric acid.

[0102] In step E6, the hydrochloric acid prepared in step E5 is used to carry out another leaching process in another step EL. In addition, sodium hydroxide is used to carry out another step E3.

[0103] In this example, the process of the invention allows the preparation of nickel, manganese and cobalt hydroxides from a raw material containing nickel, cobalt and manganese compounds without one of these metals being separated from the others during the process.

[0104] In the example, the process also allows the preparation and recycling of hydrochloric acid and sodium hydroxide by using the solution obtained after the preparation of nickel, manganese and cobalt hydroxides in step E3.

[0105] This process therefore limits the discharge of effluent and also limits the use of commercial sodium hydroxide and / or hydrochloric acid.

[0106] Furthermore, in this example, this process enabled the preparation of pCAM from MPH without separation of nickel, manganese and cobalt from each other during the process.

Claims

Demands

1. A process for preparing a mixture comprising at least one valuable metal compound selected from nickel, manganese, and cobalt hydroxides from a raw material comprising at least one valuable metal compound and at least one undesirable metal compound, the process comprising the steps of: - E1: transformation of at least one valuable metal compound and at least one undesirable metal compound into corresponding chloride complexes in an aqueous solution; - E2: selective separation of at least one undesirable metal complex from at least one valuable metal complex to obtain an intermediate solution free from undesirable metal complexes; - E3: addition of a sodium hydroxide solution to the intermediate solution to precipitate at least one valuable metal complex in the form of the corresponding hydroxide compound in a final solution;and - E4: filtration of the final solution to obtain a powder of at least one valuable metallic hydroxide and a sodium chloride solution.

2. A method according to claim 1, wherein step El is carried out using a reagent selected from hydrochloric acid, sodium hypochlorite, chlorine gas, and one of their mixtures.

3. A method according to claim 1 or 2, wherein step El comprises the addition of an oxidizing reagent or a reducing reagent to adjust the redox potential of the aqueous solution.

4. A process according to any one of the preceding claims, wherein step E2 enables the transformation of at least one valuable metal and / or at least one undesirable metal in such a way that valuable metal complexes and undesirable metal complexes have different behaviors in a reaction medium.

5. A method according to claim 4, wherein the different behavior includes different solubility depending on the pH of an aqueous composition, different solubility depending on the redox potential of a solution, and a different separation coefficient in a mixture of two immiscible solvents.

6. A process according to any one of the preceding claims, wherein step E2 comprises at least one method selected from hydrolysis to obtain a specific pH; modification of the redox potential of the solution; filtration; solvent separation, in particular an organic solvent; cementation on a metal powder; separation by ion exchange; or a combination of two or more of these methods.

7. A process according to any one of the preceding claims, wherein step E2 comprises a basic hydrolysis using a base selected from sodium hydroxide (NaOH); sodium carbonate (Na2CO3); cobalt hydroxide Co(OH)2, Ni(OH)2, Mn(OH)2, or a mixture of at least two of them; sodium bicarbonate NaHCO3; and any mixture thereof.

8. A process according to any one of the preceding claims, wherein step E2 comprises a solvent separation using an extractant solvent selected from an organophosphorus solvent, in particular an organophosphorus acid such as di(2-ethylhexyl)phosphoric acid, bis(2,4,4-trimethylpentyl)phosphonic acid, mono-2-ethylhexyl (2-ethylhexyl)phosphonate, tributyl phosphate, a trialkylphosphine oxide; a carboxylic acid; an aliphatic amine; or a mixture thereof.

9. A process according to any one of the preceding claims, wherein step E2 comprises a solvent separation using di(2-ethylhexyl)phosphoric acid as the extracting solvent.

10. A method according to any one of the preceding claims, wherein step El is carried out at a pH in the range of 0.1 to 2.

11. A process according to any one of the preceding claims, wherein step El further comprises a reducing component selected from a peroxide such as hydrogen peroxide, sodium sulfite, sodium dithionite, sodium thiosulfate, ascorbic acid, citric acid, and any mixture thereof.

12. A method according to any one of the preceding claims, wherein step E3 is carried out at a pH in the range of 6 to 7

13. U a / . A method according to any one of the preceding claims, further comprising a step E5 comprising an electrolysis of the sodium chloride solution to obtain a solution containing sodium hydroxide, chlorine and hydrogen gas.

14. A process according to claim 13, further comprising a combustion step to form hydrogen chloride followed by a step of trapping gaseous hydrogen chloride with water to produce hydrochloric acid.

15. A process according to claim 13 or 14, further comprising a step E6 comprising the use of sodium hydroxide obtained in step E4 to carry out another step E3 and / or the use of hydrochloric acid prepared in step E5 to carry out another step E1.

16. A process for preparing a precursor of cathode active materials using the process according to any one of the preceding claims, using a precipitate of mixed hydroxides as raw material.

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