Use of organic phosphine compound for selective extraction or recovery of manganese from acidic aqueous solution

Abstract

The invention relates to application of an organic phosphine compound to selective extraction or recovery of manganese from an acidic aqueous solution. These organophosphine compounds conform to the following formula (I): wherein R1 represents a C4 to C12 linear or branched alkyl group, R2 represents a C1 to C8 linear or branched alkyl group, and R3 represents H or a C1 to C12 linear or branched alkyl group. The invention also relates to the organophosphine compounds themselves. The application is as follows: recycling of waste electrical and electronic equipment (DEEE), particularly recycling of waste lithium ion electrochemical storage batteries, so as to realize resource utilization of manganese in the waste; manganese is recovered from a natural manganese source.

Description

Technical Field

[0001] This invention relates to the field of extracting and recovering manganese from acidic aqueous solutions.

[0002] More specifically, the present invention relates to the use of an organophosphorus compound for the selective extraction of manganese from an acidic aqueous solution, the acidic aqueous solution possibly containing other metals besides manganese, such as cobalt, nickel and / or lithium.

[0003] The present invention also relates to a method for selectively recovering manganese from such acidic aqueous solutions, the method using organophosphorus compounds.

[0004] This invention also relates to organophosphorus compounds themselves.

[0005] This invention is particularly applicable to the recycling of waste electrical and electronic equipment (also known as “DEEE”), especially the recycling of waste lithium-ion electrochemical batteries (commonly referred to as batteries), in order to realize the resource utilization of manganese in these batteries.

[0006] However, the present invention can also be used to recover manganese from natural manganese sources, such as pyrolusite, malachite and leucite rocks, as well as manganese nodules on the seabed. Background Technology

[0007] Lithium-ion batteries have become an indispensable element in our daily lives, as they are used in most everyday portable electronic devices, such as mobile phones and computers. These batteries are also used in electric vehicles, whose demand has increased significantly in recent years due to environmental concerns.

[0008] There are different types of lithium batteries, such as lithium polymer batteries, lithium iron phosphate batteries, lithium manganese batteries, lithium sulfur batteries, or lithium-ion batteries, among which lithium-ion batteries are the most commonly used in "consumer" electronic devices.

[0009] Lithium-ion batteries have the following advantages: high energy density, low self-discharge rate (i.e., they do not discharge rapidly when not in use), longer lifespan compared to other types of batteries, and low maintenance requirements.

[0010] However, their manufacturing costs remain high, especially due to the valuable metals contained in these battery cathode materials.

[0011] Therefore, the recycling of waste lithium-ion batteries, especially the recycling of their cathode materials, is a hot topic, both for the resource utilization of the valuable metals they contain and for environmental protection.

[0012] To date, proposed recycling processes for spent lithium-ion battery cathode materials are based on two technologies: pyrometallurgy and hydrometallurgy. Pyrometallurgy remains the most commonly used technology, but future processes will primarily employ hydrometallurgy, especially because it consumes less energy and is better suited for processing multi-metal resources.

[0013] Typically, hydrometallurgical processes first involve the production of a concentrate, which is in powder form and called "black powder," obtained by pulverizing the positive electrode of a battery. For example, in the case of NMC (nickel-manganese-cobalt) type lithium-ion batteries, the concentrate contains manganese, cobalt, nickel, and lithium as valuable metals.

[0014] Then, the "blackmass" is leached, usually with acids such as sulfuric acid. The resulting aqueous solution (also known as the leachate) undergoes a series of liquid-liquid extraction (ELL) extraction and back-extraction operations to extract and recover valuable metals.

[0015] Liquid-liquid extraction is a relatively simple technique that involves contacting an aqueous phase containing the element to be extracted with a water-insoluble organic solution (or solvent) containing one or more extractants in an organic diluent to achieve the transfer of the element from the aqueous phase to the organic solution. However, the choice of extractant is crucial for achieving high yields and selectivity for unwanted elements.

[0016] Di(2-ethylhexyl)phosphoric acid (D2EHPA) is known to be used as an extractant for the extraction of manganese and cobalt from acidic leachates, as described in application WO-A-2022 / 154316 (hereinafter referred to as [1]) or application WO-A-2022 / 147291 (hereinafter referred to as [2]).

[0017] In applications KR-A-10-2324910 (hereinafter referred to as [3]) and EP-A-4 112 557 (hereinafter referred to as [4]), the use of 2-ethylhexyl-2-ethylhexylphosphonic acid (trade name Ionquest) was also proposed. TM 801) is used as an extractant to extract manganese and cobalt from the leachate.

[0018] However, the use of these extractants is not entirely satisfactory. In particular, due to the similar pH values ​​required for extracting these metals using D2EHPA, selective extraction of manganese relative to cobalt is difficult to achieve, leading to inevitable cobalt loss.

[0019] Therefore, the inventors' objective is to provide an extractant that can extract manganese very efficiently from acidic aqueous solutions, and that can selectively extract manganese relative to other metals such as cobalt, nickel, and lithium if the solution contains such other metals. Summary of the Invention

[0020] Therefore, the present invention primarily relates to the use of organophosphorus compounds of the following formula (I):

[0021]

[0022] (I)

[0023] Where R 1 R represents a straight-chain or branched alkyl group containing 4 to 12 carbon atoms. 2 R represents a straight-chain or branched alkyl group containing 1 to 8 carbon atoms. 3 Manganese is extracted from an acidic aqueous solution A1 by means of a hydrogen atom or a straight-chain or branched alkyl group containing 1 to 12 carbon atoms.

[0024] In the foregoing and following text, “linear or branched alkyl groups containing 4 to 12 carbon atoms” means any alkyl group containing 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms (i.e., formula C). n H 2n+1 (), whose chain can be a straight chain or contain one or more branches.

[0025] Similarly, "a straight-chain or branched alkyl group containing 1 to 8 carbon atoms" refers to any alkyl group containing 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms, whose chain can also be straight or contain one or more branches.

[0026] Similarly, "a straight-chain or branched alkyl group containing 1 to 12 carbon atoms" refers to any alkyl group containing 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms, whose chain can also be straight or contain one or more branches.

[0027] Furthermore, in the preceding and following texts, the expressions “from…to…” and “between…and…” are equivalent, meaning that endpoint values ​​are included.

[0028] Similarly, the terms "solution" and "phase" are equivalent and can be used interchangeably.

[0029] In the above equation (I), R 1 The represented straight-chain or branched alkyl group preferably contains 4 to 10 carbon atoms, more preferably 6 to 9 carbon atoms, and most preferably 6, 7 or 8 carbon atoms.

[0030] R 2 The represented straight-chain or branched alkyl group preferably contains 2 to 6 carbon atoms, more preferably 2 to 5 carbon atoms, and most preferably 2, 3 or 4 carbon atoms.

[0031] As for R 3 The represented straight-chain or branched alkyl group preferably contains 1 to 8 carbon atoms.

[0032] Furthermore, regardless of R 1 and R 2 The number of carbon atoms contained in the alkyl group, preferably R 1 The alkyl group represented is a branched group having one or more branches, and / or R2 The alkyl group represented is a straight-chain group.

[0033] R 3 The preferred representation is a hydrogen atom.

[0034] Examples of organophosphorus compounds that meet these standards can be listed as follows:

[0035] - Compounds of formula (I), wherein R 1 Represents 2-methyl-4-dimethylpentyl, R 2 Represents n-butyl, R 3 Represents a hydrogen atom, hereinafter referred to as compound (Ia).

[0036] - Compounds of formula (I), wherein R 1 Represents 1-ethylpentyl, R 2 Represents n-butyl, R 3 Represents a hydrogen atom, hereinafter referred to as compound (Ib).

[0037] - Compounds of formula (I), wherein R 1 Represents 1-ethylpentyl, R 2 R represents ethyl. 3 Representing a hydrogen atom, hereinafter referred to as compound (Ic), and

[0038] - Compounds of formula (I), wherein R 1 Represents 2-methyl-4-dimethylpentyl, R 2 R represents ethyl. 3 Represents a hydrogen atom, hereinafter referred to as a compound (Id).

[0039] Among them, compounds (Ia) and (Ib) are preferred.

[0040] According to the invention, manganese is preferably extracted from solution A1 by liquid-liquid extraction, wherein the extraction of manganese comprises contacting solution A1 with an organic solution that is insoluble in water at least once, the organic solution containing the compound in an organic diluent, and then separating solution A1 from the organic solution.

[0041] However, it is also evident that manganese can be extracted from solution A1 by solid-liquid extraction, in which case the extraction may specifically involve contacting solution A1 with a water-insoluble solid material pre-impregnated with an organic solution containing the compound in an organic diluent, and then separating solution A1 from the solid material.

[0042] In any case, the organic solution preferably contains 0.1 mol / L to 1 mol / L, more preferably 0.2 mol / L to 0.5 mol / L, and most preferably 0.2 mol / L of the compound.

[0043] The preferred diluent for organic solutions is aliphatic kerosene.

[0044] However, other hydrocarbon-based diluents, preferably aliphatic diluents such as n-dodecane, tetrapropylene hydrogenate (TPH), or TotalEnergies isane, are preferred. TM IP-185 and Isane TM The isoparaffin diluent sold under the trade name IP-175 may also be applicable.

[0045] Solution A1 preferably contains 0.1 mol / L to 0.5 mol / L, more preferably 0.2 mol / L to 0.4 mol / L of a strong acid, such as sulfuric acid or hydrochloric acid.

[0046] Furthermore, solution A1 and organic solution are in contact with each other at an organic phase / aqueous phase volume ratio (O / A1), which is preferably between 1 and 5, and more preferably between 1 and 2.

[0047] Preferably, before and / or during contact between solution A1 and the organic solution, the pH of solution A1 is adjusted to a value between 2 and 5, preferably between 2 and 3, for example by adding an alkali such as sodium hydroxide.

[0048] The present invention also relates to a method for recovering manganese from an acidic aqueous solution A1, the method comprising at least the following sequential steps:

[0049] a) Extracting manganese from solution A1, the extraction comprising at least once contacting solution A1 with an organic solution insoluble in water, the organic solution containing an organophosphorus compound of formula (I) above, and then separating solution A1 from the organic solution; and

[0050] b) Back-extracting manganese from the organic solution obtained in step a), the back-extraction comprising contacting the organic solution with an acidic aqueous solution A2 at least once, and then separating the organic solution from solution A2.

[0051] In this method, the solution A1, the organic solution, and the O / A1 ratio used in step a) are preferably as described above. Furthermore, as described above, the pH of solution A1 is preferably adjusted to between 2 and 5, preferably between 2 and 3, before and / or during contact with the organic solution.

[0052] Solution A2 is preferably a solution containing 0.1 mol / L to 1.5 mol / L, more preferably 0.3 mol / L to 1.5 mol / L of a strong acid such as sulfuric acid.

[0053] Regarding the organic phase / aqueous phase volume ratio (O / A2) of the organic solution obtained in step a) in contact with solution A2, it is preferably between 0.5 and 3, more preferably between 0.5 and 1.

[0054] According to the present invention, the method may further include treating the aqueous solution obtained in step b) to convert manganese into a salt (e.g., sulfate) or an oxide (e.g., MnO2).

[0055] To obtain a salt, the process may specifically include a step of crystallization by cooling an aqueous solution to reduce the solubility of manganese and control the size of the manganese salt particles; while to obtain an oxide, the process may include, for example, oxidative precipitation in the presence of hydrogen peroxide, permanganate, or ammonium persulfate.

[0056] In addition to being able to extract manganese very efficiently from acidic aqueous solutions, the compounds of formula (I) have also been shown to achieve excellent separation of manganese from metals that may be present in the solution, particularly cobalt, nickel and lithium.

[0057] Therefore, the uses and recovery methods described above are advantageous for extracting / recovering manganese from acidic aqueous solutions that contain cobalt, nickel and / or lithium in addition to manganese.

[0058] The acidic aqueous solution can be a solution obtained by acid leaching of waste lithium-ion battery cathode material powder (or black powder), which may have been pre-removed of metals considered as impurities (as opposed to valuable metals such as manganese, cobalt, nickel and lithium), such as iron, aluminum and copper, wherein the cathode material is preferably NMC cathode material, more specifically NMC111 cathode material, which is characterized by containing equal proportions of nickel, manganese and cobalt.

[0059] Therefore, the manganese recovery method according to the present invention can be integrated into a more comprehensive acid leaching process for NMC cathode material powder, which, in addition to selectively recovering manganese, also includes selectively recovering cobalt, nickel and lithium.

[0060] The present invention also relates to organophosphorus compounds of formula (I) as described above.

[0061] Other features and advantages of the present invention will become apparent from the following supplementary description.

[0062] It goes without saying that this supplementary description is merely an example of the subject matter of this invention and should not be construed in any way as limiting the subject matter of this invention. Attached Figure Description

[0063] Figure 1 The effect of pH on the extraction of manganese, cobalt, nickel, and lithium from an aqueous solution by a compound of formula (I) (referred to as compound (Ia)) is shown and compared with an extractant of the prior art (D2EHPA), the aqueous solution representing a leachate of lithium-ion battery NMC cathode material powder; in this figure, the horizontal axis corresponds to pH, and the vertical axis corresponds to the extraction rate (R). M ), expressed as %.

[0064] Figure 2 Is with Figure 1 A similar diagram, but for the second type of compound (I), is called compound (Ib).

[0065] Figure 3 The figure shows the effect of the concentration of compound (Ia) in the organic phase on the extraction of manganese, cobalt, nickel, and lithium from an aqueous leachate representing NMC cathode material powder from a lithium-ion battery. In this figure, the horizontal axis corresponds to the concentration of compound (Ia), denoted as [(Ia)], expressed in mol / L, and the vertical axis corresponds to the extraction rate (R). M ), expressed as %.

[0066] Figure 4 Is with Figure 3 A similar diagram, but for compound (Ib).

[0067] Figure 5 The figure illustrates the effect of the organic / aqueous phase volume ratio (O / A) on the extraction of manganese, cobalt, nickel, and lithium by compound (Ia) from an aqueous solution representing a lithium-ion battery NMC cathode material leachate; in this figure, the horizontal axis corresponds to the organic / aqueous phase volume ratio (O / A), and the vertical axis corresponds to the extraction rate (R). M ), expressed as %.

[0068] Figure 6 Is with Figure 5 A similar diagram, but for compound (Ib).

[0069] Figure 7 The back-extraction rate (denoted as R) is shown. M The variation (in %) with the pH of the aqueous phase used for back-extraction. The back-extraction experiment was carried out on an organic phase containing manganese, cobalt, nickel, and lithium, as well as a compound (Ia) dissolved in aliphatic kerosene at a concentration of 0.2 mol / L.

[0070] Figure 8 Is with Figure 7 A similar diagram, but for an organic phase containing compound (Ib).

[0071] Figure 9 This is an example schematic diagram illustrating the integration of the manganese recovery method of this invention into a more comprehensive treatment process for the acid leaching solution of NMC cathode material powder. Detailed Implementation

[0072] Example 1: Synthesis of organophosphorus compounds of formula (I)

[0073] Where R 3The synthesis of organophosphorus compounds of formula (I), representing hydrogen atoms, is carried out in two steps without the need for additional purification steps such as silica gel chromatography, thus simplifying the synthesis.

[0074] The synthesis was carried out according to the following reaction scheme:

[0075]

[0076] Where R 1 and R 2 As mentioned above.

[0077] Where R 3 Representing C1 to C 12 The synthesis of straight-chain or branched alkyl organophosphorus compounds of formula (I) can be similar to the synthesis described above, except that a C-alkylation reaction (as known in the art) is performed on the α-carbon atom of the phosphorus atom in compound 2.

[0078] 1.1.1. Synthesis of intermediate compound 1

[0079] 10 mmol of formula R 1 The aldehyde of C(O)H and 10 mmol of HP(O)(OR) 2 Add phosphite of 2 to a single-necked flask. Stir the mixture at room temperature for 5 minutes, then add 3 g of anhydrous K2CO3 to the flask while continuing to stir.

[0080] The reaction process was monitored using thin-layer chromatography. According to R... 1 and R 2 Depending on the nature of the functional groups, the reaction time can vary between 10 and 30 minutes. Once the reactants are completely converted, add 30 mL of dichloromethane to the reaction mixture. Then filter the reaction medium and wash with dichloromethane to remove K₂CO₃.

[0081] Intermediate compound 1 was isolated from dichloromethane by vacuum evaporation and can be used in the next step without purification.

[0082] 1.1.2. Synthesis of organophosphine compound 2

[0083] Organophosphine compound 2 was obtained by selective hydrolysis of intermediate compound 1.

[0084] For this purpose, intermediate compound 1 was added to a three-necked flask equipped with a condenser, followed by 15 mL of dichloromethane. The reaction was carried out under an inert atmosphere, such as nitrogen. Then, 10 mmol of trimethylsilyl bromide (Me3SiBr) was added dropwise, and the reaction mixture was stirred for 30 minutes. Afterward, 2 mL of methanol was added to the reaction mixture, followed by 2 mL of water, to remove residual Me3SiBr.

[0085] The resulting reaction mixture was transferred to a separatory funnel and diluted with 40 mL of dichloromethane.

[0086] First, wash the organic phase with 30 mL of 1 mol / L hydrochloric acid solution, and then wash twice with 20 mL of distilled water.

[0087] After settling and separation, the organic phase was separated from the aqueous phase. The recovered organic phase was dried with magnesium sulfate (MgSO4) and then filtered. Subsequently, dichloromethane was evaporated under reduced pressure to obtain organophosphorus compound 2.

[0088] Therefore, the following was specially synthesized:

[0089] - The compound represented by formula (Ia):

[0090]

[0091] (Ia)

[0092] Through formula R 1 Aldehydes of C(O)H (where R) 1 (representing the -CH2CH(CH3)CH2C(CH3)3 group) and the formula HP(O)(OR) 2 )2 phosphite (where R 2 It is prepared by the reaction of (representing the –(CH2)3CH3 group), and its characterization is as follows:

[0093] ¹H nuclear magnetic resonance (NMR) 1 ¹H NMR (CDCl₃ / TMS, 400 MHz) δ(ppm): 7.26 (broad singlet, OH), 4.08 (triple doublet, J = 6.8 Hz, 2H), 3.98–3.89 (multiplet, 1H), 1.91–1.10 (multiplet, 12H), 0.97 (singlet, 9H), 0.94 (doublet, J = 7.0 Hz, 3H), 0.91 (triplet, J = 7.0 Hz, 3H);

[0094] 31 P nuclear magnetic resonance (P nuclear magnetic resonance) 31 P NMR) (CDCl3 / H3PO4, 100.75 MHz): δ 26.75 (ppm);

[0095] Fourier transform infrared spectrum (FT-IR): 3320 cm⁻¹ -1 (γ OH), 1025 cm -1 (γ P=O);

[0096] Mass spectrometry (MS): C 11 H 25The theoretical m / z value of O4P is 280.18; the measured value is 280.22.

[0097] - The compound represented by formula (Ib):

[0098]

[0099] (Ib)

[0100] Through formula R 1 Aldehydes of C(O)H (where R) 1 (representing the -CH(C2H5)(CH2)3CH3 group) and the formula HP(O)(OR) 2 )2 phosphite (where R 2 It is prepared by reacting (representing the -(CH2)3CH3 group) and its characterization is as follows:

[0101] ¹H NMR (CDCl3 / TMS, 400 MHz) δ (ppm): 6.93 (broad singlet, OH), 4.13 (triplet, J = 6.8 Hz, 2H), 4.02–3.93 (multiplet, 1H), 1.82–1.24 (multiplet, 13H), 0.95 (triplet, J = 7.6 Hz, 3H), 0.93 (triplet, J = 7.6 Hz, 3H), 0.92 (triplet, J = 7.6 Hz, 3H);

[0102] 31 P NMR (CDCl3 / H3PO4, 100.75 MHz): δ 27.28 ppm;

[0103] Fourier transform infrared spectrum: 3300 cm⁻¹ -1 (γ OH), 1022 cm -1 (γ P=O);

[0104] Mass spectrometry: C 11 H 25 The theoretical m / z value of O4P is 266.31; the measured value is 266.38.

[0105] - The compound represented by formula (Ic):

[0106]

[0107] (Ic)

[0108] Through formula R 1 Aldehydes of C(O)H (where R) 1 (representing the -CH(C2H5)(CH2)3CH3 group) and the formula HP(O)(OR) 2)2 phosphite (where R 2 It is prepared by reacting (representing the -CH2CH3 group) and its characterization is as follows:

[0109] ¹H NMR (CDCl3 / TMS, 400 MHz) δ (ppm): 6.90 (broad singlet, OH), 4.14 (quartet, J = 7.0 Hz, 2H), 3.93–3.87 (multiplet, 1H), 1.72–1.27 (multiplet, 9H), 1.31 (triplet, J = 7.0 Hz, 3H), 0.91 (triplet, J = 7.0 Hz, 3H), 0.89 (triplet, J = 7.0 Hz, 3H);

[0110] 31 P NMR (CDCl3 / H3PO4, 100.75 MHz): δ 27.57 ppm;

[0111] Fourier transform infrared spectrum: 3334 cm⁻¹ -1 (γ OH), 1026 cm -1 (γ P=O);

[0112] Mass spectrometry: C 11 H 25 The theoretical m / z value of O4P is 238.26; the measured value is 238.17.

[0113] The compound represented by formula (Id):

[0114]

[0115] (Id)

[0116] Through formula R 1 Aldehydes of C(O)H (where R) 1 (representing the -CH2CH(CH3)CH2C(CH3)3 group) and the formula HP(O)(OR) 2 )2 phosphite (where R 2 It is prepared by reacting (representing the -CH2CH3 group) and its characterization is as follows:

[0117] ¹H NMR (CDCl3 / TMS, 400 MHz) δ (ppm): 6.06 (broad singlet, OH), 4.15 (quartet, J = 6.9 Hz, 2H), 3.96 (multiplet, 1H), 1.91–1.52 (multiplet, 2H), 1.31 (triplet, J = 6.9 Hz, 3H), 1.28–1.10 (multiplet, 3H), 1.11 and 1.05 (two doublets, J = 7.0 Hz, 3H), 1.05 (singlet, 9H);

[0118] 31 P NMR (CDCl3 / H3PO4, 100.75 MHz): δ 26.90 ppm;

[0119] Fourier transform infrared spectrum: 3328 cm⁻¹ -1 (γ OH), 1025 cm -1 (γ P=O);

[0120] Mass spectrometry: C 11 H 25 The theoretical m / z value of O4P is 252.29; the measured value is 252.11.

[0121] Example 2: Application of organophosphorus compounds as extractants

[0122] 2.1 – Extraction performance of compounds in chloride media

[0123] The first series of extraction experiments used:

[0124] - As the aqueous phase: aliquots of an aqueous solution containing manganese(II), cobalt(II), nickel(II), and lithium(I), prepared by dissolving appropriate amounts of manganese chloride (MnCl2), cobalt chloride (CoCl2), nickel chloride (NiCl2), and lithium chloride (LiCl) in 0.2 mol / L hydrochloric acid (pH = 0.7); and

[0125] - As the organic phase: four solutions, each containing one of compounds (Ia) to (Id) at a concentration of 0.1 mol / L, dissolved in aliphatic kerosene.

[0126] Prior to the extraction experiment, the mass concentration of each metal element in the aqueous solution was determined using an Agilent™ MP-AES 4210 microwave inductively coupled plasma atomic emission spectrometer.

[0127] The composition of the aqueous solution is shown in Table I below.

[0128] Table I

[0129]

[0130] Then add 5 mol / L sodium hydroxide to the aqueous solution until the pH reaches 5.

[0131] In each extraction experiment, 10 mL of aqueous solution was aliquoted into the sample and 10 mL of one of the organic phases was contacted in a test tube (i.e., the organic phase / aqueous phase volume ratio (O / A) was 1). The sample was shaken at 200 rpm for 15 minutes at room temperature (25°C) in a Gerhardt thermostatic shaker, and then centrifuged at 5000 rpm for 2 minutes to separate the aqueous and organic phases.

[0132] If necessary, add 5 mol / L sodium hydroxide during the extraction process to bring the aqueous phase to equilibrium at pH 5.

[0133] The recovered aqueous phase was filtered through a Minisart™ hydrophilic membrane with a pore size of 0.45 μm to remove organic phase droplets that were stabilized in the aqueous phase due to mechanical entrainment.

[0134] Subsequently, the mass concentrations of residual manganese, cobalt, nickel, and lithium in the aqueous phase were determined using a microwave inductively coupled plasma atomic emission spectrometer (Agilent™ MP-AES 4210).

[0135] For each of compounds (Ia) to (Id), the extraction rate (R) of each metal element M (represented by %) is determined by the following equation:

[0136]

[0137] Where D M The partition coefficient (DM) corresponding to the metal element between the organic and aqueous phases is determined by the following equation:

[0138]

[0139] in:

[0140] It refers to the concentration of the metal element in the aqueous phase after extraction.

[0141] It is the concentration of the metal element in the aqueous phase before extraction.

[0142] The extraction rates obtained are listed in Table II below.

[0143] Table II

[0144]

[0145] The table shows that compounds (Ia) and (Ib) are able to extract manganese very efficiently from acidic aqueous solutions, with extraction rates exceeding 60%, while the extraction rates for cobalt, nickel, and lithium are lower.

[0146] The manganese extraction rates obtained using compounds (Ic) and (Id) are lower than those obtained using compounds (Ia) and (Ib), but they are still of reference value, especially considering that compound (Ic) cannot extract cobalt, nickel, and lithium, or can hardly extract them, and that compound (Id) has low extraction rates for these metals.

[0147] 2.2 – Extraction performance of compounds in sulfate media

[0148] The second series of extraction experiments used:

[0149] - As an aqueous phase: equal aliquots of an aqueous solution, the composition of which represents the leachate from the NMC111 cathode material of a lithium-ion battery after sulfuric acid leaching. This aqueous solution is prepared by dissolving appropriate amounts of manganese sulfate (MnSO4), cobalt sulfate (CoSO4), nickel sulfate (NiSO4), and lithium sulfate (Li2SO4) in 0.35 mol / L sulfuric acid (pH = 0.46); and

[0150] - As an organic phase: two solutions, one containing compound (Ia) and the other containing compound (Ib), dissolved in aliphatic kerosene.

[0151] The effects of different parameters on the extraction performance of compounds (Ia) and (Ib) were investigated, namely:

[0152] pH of the aqueous phase

[0153] The concentrations of these compounds in the organic phase, and

[0154] Organic phase / aqueous phase volume ratio (O / A).

[0155] Prior to the extraction experiment, the mass concentration of each metal element in the aqueous solution was determined using a microwave inductively coupled plasma atomic emission spectrometer (Agilent™ MP-AES 4210).

[0156] The composition of the aqueous solution is shown in Table III below.

[0157] Table III

[0158]

[0159] For each research parameter, the extraction experiment was performed according to the following steps:

[0160] - Adjust the initial pH of the aqueous phase to the desired value;

[0161] - Contact one of the aqueous phases and one of the organic phases in a test tube at a specific organic phase / water phase volume ratio (O / A);

[0162] - The two-phase mixture was shaken at 200 rpm for 15 minutes at room temperature (25°C) in a Gerhardt thermostatic shaker while the equilibrium pH of the aqueous phase was adjusted to the same value as the initial pH.

[0163] - Centrifuge the two-phase mixture at 3,000 rpm for 2 minutes to separate the aqueous and organic phases;

[0164] - The recovered aqueous phase is filtered using a Minisart™ hydrophilic filter membrane with a pore size of 0.45 μm;

[0165] - The mass concentrations of residual manganese, cobalt, nickel, and lithium in the aqueous phase were determined using a microwave inductively coupled plasma atomic emission spectrometer (Agilent™ MP-AES 4210); and

[0166] - Calculate the extraction rates of manganese, cobalt, nickel, and lithium.

[0167] 2.2.1 - The effect of pH

[0168] The experiment assessing the effect of pH was conducted under the following conditions:

[0169] - Adjust the initial pH to a value between 0.5 and 5.

[0170] - The volume of the aqueous phase is 5 mL, and the volume of the organic phase is 5 mL (i.e., the organic phase / aqueous phase volume ratio (O / A) is 1).

[0171] - The concentration of compound (Ia) or (Ib) in the organic phase is 0.2 mol / L, and

[0172] - Adjust the equilibrium pH to the same value as the initial pH.

[0173] For comparison, extraction experiments were also conducted using the extractant proposed in references [1] and [2] (i.e., di(2-ethylhexyl)phosphoric acid (D2EHPA)), following the same operating procedures and conditions, but with the concentration of D2EHPA in the organic phase being 0.8 mol / L.

[0174] The results of these experiments are shown in Figure 1 (Compound (Ia)) and Figure 2 (Compound (Ib)), in each figure, these results are compared with those obtained by D2EHPA.

[0175] These figures show that compounds (Ia) and (Ib) achieved the same extraction rates.

[0176] These figures also show that manganese is extracted very selectively at pH 2.1. Furthermore, at this pH, the manganese extraction rate obtained using D2EHPA is much lower than that obtained using compounds (Ia) and (Ib), even though the concentration in the organic phase is much lower than that of D2EHPA (0.2 mol / L vs. 0.8 mol / L).

[0177] Therefore, the compounds of formula (I) have properties that make them more attractive than D2EHPA, and can be used for the selective extraction of manganese from acidic aqueous solutions, not only in terms of extraction capacity but also in terms of the amount of extractant used. In particular, as mentioned above, these compounds are simple to synthesize and do not require purification.

[0178] 2.2.2 - Effect of compound concentration in organic phase

[0179] The experiment evaluating the effect of compound concentration in the organic phase was conducted under the following conditions:

[0180] - Adjust the initial pH to 2.1.

[0181] - The volume of the aqueous phase is 5 mL, and the volume of the organic phase is 5 mL (i.e., the organic phase / aqueous phase volume ratio (O / A) is 1).

[0182] - The concentration of compound (Ia) or (Ib) in the organic phase is from 0.2 mol / L to 1 mol / L, and

[0183] - Adjust the equilibrium pH to the same value as the initial pH (i.e., 2.1).

[0184] The results of these experiments are shown in Figure 3 (Compound (Ia)) and Figure 4 (Compound (Ib)).

[0185] These figures show that the results for the two tested compounds are essentially the same, with the extraction rates of manganese and other metal elements increasing as the concentration of the compounds in the organic phase increases.

[0186] Using compound (Ia) or compound (Ib) at a concentration of 0.2 mol / L in the organic phase is particularly meaningful because it can achieve a manganese extraction rate of about 50% while exhibiting high selectivity for this element.

[0187] 2.2.3 - Effect of organic / aqueous volume ratio (O / A)

[0188] The experiment evaluating the effect of the organic / aqueous phase volume ratio (O / A) was conducted under the following conditions:

[0189] - Adjust the initial pH to 2.3.

[0190] - The volume of the aqueous phase is 5 mL, and the volume of the organic phase is 1 mL to 30 mL, i.e., the organic phase / aqueous phase volume ratio (O / A) is 0.2 to 6.

[0191] - The concentration of compound (Ia) or (Ib) in the organic phase is 0.2 mol / L, and

[0192] - Adjust the equilibrium pH to the same value as the initial pH (i.e., 2.3).

[0193] The results of these experiments are shown in Figure 5 (Compound (Ia)) and Figure 6 (Compound (Ib)).

[0194] These figures also show that the results for the two tested compounds are essentially the same.

[0195] These figures also show that when the organic phase / aqueous phase volume ratio reaches 4, the extraction rate of manganese reaches about 90%, but regardless of whether compound (Ia) or compound (Ib) is used, 20% to 30% of other metal elements are co-extracted.

[0196] Therefore, it is more advantageous to use a lower organic phase / aqueous phase volume ratio (O / A), especially 1.5, because this allows for the extraction of about 70% of manganese in a single step without significantly extracting other metal elements.

[0197] 2.3 – Back-extraction of manganese

[0198] The back-extraction test was performed under the following conditions:

[0199] - As organic phases: Equal samples of two organic phases, one containing compound (Ia) and the other containing compound (Ib), at a concentration of 0.2 mol / L, dissolved in aliphatic kerosene. These organic phases were preloaded with manganese, cobalt, nickel, and lithium by extraction of manganese, cobalt, nickel, and lithium from an aqueous solution of the leachate representing the NMC111 cathode material of a lithium-ion battery after leaching with sulfuric acid (0.35 mol / L); and

[0200] - As the aqueous phase: an aqueous solution of sulfuric acid with a concentration of 0.1 mol / L to 1.5 mol / L.

[0201] Extraction was performed according to the same operating procedure described in Section 2.2 above, using an organic phase / aqueous phase volume ratio (O / A) of 1.6, and adjusting the initial pH and equilibrium pH to 2.6.

[0202] Table IV below lists the pre-extraction ( ) and after extraction ( The mass concentrations of manganese, cobalt, nickel, and lithium in the aqueous phase (determined by microwave inductively coupled plasma atomic emission spectrometry (MP-AES)) and their extraction rates (denoted as R) M ), respectively targeting compounds (Ia) and (Ib).

[0203] Table IV

[0204]

[0205] In each back-extraction experiment, the organic phase loaded with metal elements and the aqueous phase for back-extraction were contacted in a test tube with an organic phase / aqueous phase volume ratio (O / A) of 1. The mixture was shaken at 200 rpm for 30 minutes at 30°C in a Gerhardt constant temperature shaker, and then centrifuged at 3000 rpm for 2 minutes to separate the aqueous and organic phases.

[0206] The recovered aqueous phase was filtered through a Minisart™ hydrophilic membrane with a pore size of 0.45 μm to remove organic droplets that were mechanically entrained in the aqueous phase. The mass concentrations of manganese, cobalt, nickel, and lithium in the aqueous phase were determined using a microwave inductively coupled plasma atomic emission spectrometer (Agilent™ MP-AES4210), and the back-extraction rates of each metal element were calculated.

[0207] The results of these back-extraction experiments are shown in Figure 7 (Compound (Ia)) and Figure 8 (Compound (Ib)).

[0208] These figures show that when the sulfuric acid concentration reaches 0.3 mol / L, the sulfuric acid concentration in the back-extraction solution has little effect on the back-extraction rates of manganese, cobalt, nickel, and lithium, and these back-extraction rates remain almost constant regardless of whether the extractant is compound (Ia) or compound (Ib).

[0209] These figures also show that sulfuric acid solution can effectively back-extract manganese, while limiting the back-extraction of other metal elements.

[0210] For example, Table V below lists the organic phase before back-extraction when using a 1.5 mol / L sulfuric acid back-extraction solution ( ) and the aqueous phase after back-extraction ( The mass concentrations of manganese, cobalt, nickel and lithium are given for compounds (Ia) and (Ib), respectively.

[0211] Table V

[0212]

[0213] It is important to note that the above results were obtained through a single-stage extraction-back-extraction process. Increasing the number of stages can reduce the content of cobalt, nickel, and lithium in the aqueous solution obtained from the last stage of manganese back-extraction, while reducing the organic phase / aqueous phase volume ratio (O / A) can concentrate the manganese in the solution, thus facilitating its crystallization as manganese sulfate or its oxidative precipitation as manganese oxide.

[0214] Example 3: The manganese recovery method of the present invention is integrated into a more comprehensive treatment process for the acid leaching solution of NMC cathode material powder.

[0215] See Figure 9 The figure illustrates an example schematic diagram of the manganese recovery method of the present invention—represented by a dashed box in the figure—integrated into a more comprehensive treatment process for the acid leaching solution of NMC cathode material powder.

[0216] like Figure 9 As shown, this comprehensive process, after the step of removing metallic impurities such as iron, copper, and aluminum from the leaching solution (e.g., by liquid-liquid extraction of copper using an Acorga™ type (e.g., available from Solvay) or LIX™ type (e.g., available from BASF) extractant at pH 1 to 2, or by precipitating iron or aluminum by raising the pH to 3), includes the following sequential steps:

[0217] - By selectively recovering manganese by implementing the method of the present invention, it is therefore included to extract manganese from the leachate, then back-extract manganese from the organic phase obtained after extraction, and convert the back-extracted manganese into a salt (e.g., MnSO4) or an oxide.

[0218] - Selective recovery of cobalt from the aqueous phase obtained after manganese extraction in the previous step, such recovery including, for example, using a solution containing Cyanex. TM 272 The water-insoluble organic phase, used as an extractant, extracts cobalt from the aqueous phase, and then back-extracts cobalt from the organic phase, converting the back-extracted cobalt into a salt (e.g., CoSO4).

[0219] - Selective recovery of nickel from the aqueous phase obtained after manganese extraction, for example by precipitating nickel as nickel hydroxide; and

[0220] - Selectively recover lithium from the aqueous phase obtained after nickel precipitation, for example by precipitating lithium as lithium carbonate.

[0221] This allowed for the recovery of four valuable metals, including manganese, that were initially present in the leachate.

[0222] References

[0223] [1] WO 2022 / 154316

[0224] [2] WO 2022 / 147291

[0225] [3] KR 10-2324910

[0226] [4] EP 4112557

Claims

1. Uses of an organophosphorus compound of formula (I): (I) in: R 1 Represents straight-chain or branched alkyl groups containing 4 to 12 carbon atoms. R 2 Represents straight-chain or branched alkyl groups containing 1 to 8 carbon atoms, and R 3 Represents a hydrogen atom or a straight-chain or branched alkyl group containing 1 to 12 carbon atoms. Manganese was extracted from acidic aqueous solution A1 as an extractant.

2. The use according to claim 1, wherein R 1 It represents a straight-chain or branched alkyl group containing 4 to 10 carbon atoms, preferably 6 to 9 carbon atoms, and more preferably 6, 7 or 8 carbon atoms.

3. The use according to claim 1 or claim 2, wherein R 2 It represents a straight-chain or branched group containing 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms, and more preferably 2, 3 or 4 carbon atoms.

4. The use according to any one of claims 1 to 3, wherein: R 1 Represents branched alkyl groups, and / or R 2 Represents straight-chain alkyl groups, and / or R 3 It represents a hydrogen atom.

5. The use according to any one of claims 1 to 4, wherein the compound is selected from: Compounds of formula (I), wherein R 1 Represents 2-methyl-4-dimethylpentyl, R 2 Represents n-butyl, R 3 Represents a hydrogen atom. Compounds of formula (I), wherein R 1 Represents 1-ethylpentyl, R 2 Represents n-butyl, R 3 Represents a hydrogen atom. Compounds of formula (I), wherein R 1 Represents 1-ethylpentyl, R 2 Represents ethyl, R 3 Represents hydrogen atoms, and Compounds of formula (I), wherein R 1 Represents 2-methyl-4-dimethylpentyl, R 2 Represents ethyl, R 3 It represents a hydrogen atom.

6. The use according to claim 5, wherein the compound is a compound of formula (I), wherein R 1 Represents 2-methyl-4-dimethylpentyl or 1-ethylpentyl, R 2 Represents n-butyl, R 3 It represents a hydrogen atom.

7. The use according to any one of claims 1 to 6, wherein the extraction of manganese comprises contacting solution A1 with an organic solution insoluble in water at least once, the organic solution containing the compound in an organic diluent, and then separating solution A1 from the organic solution.

8. The use according to claim 7, wherein the organic solution comprises 0.1 mol / L to 1 mol / L, preferably 0.1 mol / L to 0.5 mol / L, more preferably 0.2 mol / L of the compound.

9. The use according to any one of claims 1 to 8, wherein solution A1 contains 0.1 mol / L to 0.5 mol / L, preferably 0.2 mol / L to 0.4 mol / L, a strong acid, preferably sulfuric acid or hydrochloric acid.

10. The use according to any one of claims 7 to 9, wherein the solution A1 and the organic solution are in contact at an organic phase / aqueous phase volume ratio (O / A) of 1 to 5, preferably 1 to 2.

11. The use according to any one of claims 7 to 10, wherein the pH of solution A1 is adjusted to a value between 2 and 5, preferably between 2 and 3, before and / or during contact with the organic solution.

12. A method for recovering manganese from an acidic aqueous solution A1, the method comprising at least the following sequential steps: a) Extracting manganese from solution A1, the extraction comprising at least once contacting solution A1 with an organic solution insoluble in water, the organic solution comprising an organophosphorus compound conforming to formula (I) as defined in any one of claims 1 to 6, and then separating solution A1 from the organic solution; and b) Back-extracting manganese from the organic solution obtained in step a), the back-extraction comprising contacting the organic solution with an acidic aqueous solution A2 at least once, and then separating the organic solution from the acidic aqueous solution A2.

13. The method according to claim 12, wherein the organic solution comprises 0.1 mol / L to 1 mol / L, preferably 0.1 mol / L to 0.5 mol / L, more preferably 0.2 mol / L of the compound.

14. The method according to claim 12 or claim 13, wherein solution A1 contains 0.1 mol / L to 0.5 mol / L, more preferably 0.2 mol / L to 0.4 mol / L, a strong acid, preferably sulfuric acid or hydrochloric acid.

15. The method according to any one of claims 12 to 14, wherein in step a), solution A1 and organic solution are contacted at an organic phase / aqueous phase volume ratio (O / A) between 1 and 5, preferably between 1 and 2.

16. The method according to any one of claims 12 to 15, wherein the pH of solution A1 is adjusted to a value between 2 and 5, preferably between 2 and 3, before and / or during contact with the organic solution.

17. The method according to any one of claims 12 to 16, wherein solution A2 contains 0.1 mol / L to 1.5 mol / L, more preferably 0.3 mol / L to 1.5 mol / L, a strong acid, preferably sulfuric acid.

18. The method according to any one of claims 12 to 17, wherein in step b), the organic solution obtained in step a) is in contact with solution A2 at an organic phase / aqueous phase volume ratio (O / A) of 0.5 to 3, preferably between 0.5 and 1.

19. The method according to any one of claims 12 to 18, further comprising treating the aqueous solution obtained in step b) to convert manganese into a salt or oxide.

20. The use according to any one of claims 1 to 11 or the method according to any one of claims 12 to 19, wherein solution A1 contains cobalt, nickel and / or lithium in addition to manganese.

21. The use or method according to claim 20, wherein solution A1 is derived from acid leaching of spent lithium-ion battery cathode material powder, preferably NMC cathode material.

22. An organophosphorus compound conforming to formula (I) as defined in any one of claims 1 to 6, but excluding compounds conforming to the following formula: 。

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