Hydrophobic organic liquid composition for the selective extraction of a lithium salt

Abstract

The present invention relates to a hydrophobic organic liquid composition for the selective extraction of a di-ionic lithium salt comprising a lithium cation and an anion complementary to the lithium cation, chosen in particular from Cl, I, Br, CN, MK and HCO 3, from a lithium-rich brine to be treated, said composition comprising (A) at least one compound extracting the lithium cation, chosen from the compounds of formula: (I) in which R1, R2, R3, R4, R5 and R6 are as defined in the description; (B) at least one organic, protic and hydrophobic compound solvating the anion complementary to the lithium cation; and (C) at least one hydrophobic polar organic diluent having a flash point at atmospheric pressure greater than 60°C, preferably greater than 75°C, more preferably greater than 90°C.

Description

[0001] Description

[0002] Title of the invention: Hydrophobic organic liquid composition for the selective extraction of a lithium salt.

[0003] The present invention relates to a hydrophobic organic liquid composition for the selective extraction of a lithium salt.

[0004] As part of the energy transition, global targets for replacing vehicles that emit 20% of global CO2 with electric vehicles mean that global production of metals such as lithium, nickel, cobalt, copper, manganese, etc. needs to be increased. In particular, lithium, which is essential for the construction of lithium-ion batteries, is expected to see its production quadrupled between 2020 (990 kt lithium carbonate equivalent (LCE)) and 2030 (3,700 kt LCE) for the construction of sixteen times more electric vehicles and to supply more than three hundred new battery factory projects.

[0005] Due to this very strong demand which exceeds supply, the price of Lithium has increased from 16,750 US$ / tonne LCE in 2018 to 71,750 US$ / tonne LCE in 2022. However, this excess demand is not likely to diminish quickly due to lithium mining production resources not being able to keep up with demand.

[0006] Indeed, if lithium is widely available on earth, either in the form of mineral rock (Spodumene, Lepidolite, Petalite...), or in the form of salt (LiCl, Li2SO4...) dissolved or not dissolved in water, its extraction (186 kt Li) is still relatively modest today compared to other metals of the energy transition amounting to millions of tonnes (Iron: 1,500 Mt; Aluminum: 65 Mt; Copper: 20 Mt; Manganese: 19 Mt; Zinc: 12 Mt; Chromium: 12 Mt; Titanium: 8 Mt; Lead: 4.7 Mt; Nickel: 2.5 Mt).

[0007] In particular, lithium-rich brines are usually collected from the natural environment as continental brines from Andic or Tibetan endorheic basins, oil production water brines, geothermal brines and others.

[0008] In current applications, salt mines with high LiCl concentrations use salt marshes to evaporate water from brines extracted from the subsoil and allow the reconcentration of lithium from 200-2000 mg / L to more than 50 g / L or even up to 80 g / L. This phase is carried out on hundreds of hectares of evaporation ponds that take a long time to build (3 to 4 years) and must be maintained over time to avoid leaks and infiltration. In addition, this natural evaporation is dependent on sunshine and the general climate with a reconcentration phase lasting from 12 to 24 months to go from the well to the production of this concentrate, generating variability in production, both in volume and quality, associated with millions of tons of crystallized salt (NaCl, Na2SO4, K3Na(SO4)2, KC1, Na2Mg(SO4)2.4H2O...) to be evacuated regularly to maintain an evaporation-crystallization capacity.

[0009] After this first phase, a lithium concentrate is obtained that can integrate all the ions of the starting brine, which today generates the implementation of numerous downstream brine treatment stages to remove mineral impurities other than lithium in order to finally obtain the desired lithium, generally in the form of L12CO3 after carbonation. Thus, it is common to operate after these solar evaporation ponds several units placed in series to extract boron by liquid-liquid extraction, then to chemically precipitate calcium, magnesium and sulfates, followed by a KC1 crystallizer, then ion exchange resins to finally reach the final carbonation unit. This ensures the separation of the residual sodium Na + and lithium Li + via precipitation at 80°C of lithium carbonate L12CO3 by addition of sodium carbonate Na2CO3:

[0010] LiCl(aq) + Na2CO3( s)=> Li2CO3( s )+ NaCl(aq).

[0011] The presence of sodium in the resulting concentrated LiCl brine also makes it impossible to directly produce battery-grade LiOH.ïbO. It is therefore used after a first carbonation of LiCl to Li2CO3, a second carbonation after redissolving the latter to achieve a sufficient level of L12CO3 purity before its chemical conversion by electrolysis to LiOH or by adding Ca(OH)2via:

[0012] Ca(0H)2(aq) + Li2CO3( s )=> 2 LiOH( a q)+ CaCO3( s ).

[0013] Being able to achieve direct conversion of LiCl to LiOH.ïbO would reduce operating expenses (OPEX) by at least US$2,500 / tonne LiOH.ïbO, making this sector much more competitive. This production route is forced to improve both productivity, lithium yield and purity, and cost to keep up with the strong demand for lithium while delivering top-notch Environmental, Social and Governance (ESG) results.

[0014] Thus, for example, due to the high consumption of water by evaporation of brine, there are more and more restrictions in producing countries, led by Chile, regarding the maintenance of solar evaporators considered potentially unsustainable on very arid Andean plateaus (15 to 100 mm of precipitation / year).

[0015] Other historical problems of lithium production from brines are also known in China, Bolivia and to a lesser extent in Argentina due to brine compositions too rich in magnesium and / or sulfate. Indeed, for example, when a Mg / Li mass ratio > 6 is reached, lithium can co-precipitate with magnesium due to similar physical and chemical properties making their separation difficult (precipitates of Carnalite (MgCl2.KCl.6H2O), bischofite (MgC12.6H2O), Lithium carnalite (LiCl.MgCl2.7H2O)...). Thus, in China, in the Qinghai Tibetan highlands region, Mg / Li ratios of 10 to 40 are common, even up to 100. In addition, in the strong presence of sulfate, other combined salts can integrate lithium and generate its loss by coprecipitation (precipitates of Astrakanite (Na2Mg (SO4)2•4H2O), Schoenite (K2Mg (SO4)2•6H2O), Leonite (K2Mg (SO4)2•4H2O), Kainite (MgSO4.KCl.3H2O), Epsomite (MgSO4.7H2O)...).Thus this solar reconcentration stage can generate 40% to more than 70% of lithium losses by co-precipitation and by carrying away lithium-rich brine, which can generate in certain brines a loss of lithium so significant that this implementation becomes uneconomical and non-ecological.

[0016] However, the lithium present in brines represents 75 to 80% of the world's lithium resources, far ahead of pegmatite mines.

[0017] The object of the invention aims to resolve all of these difficulties by implementing a solution for the selective extraction of LiCl from brines in the presence of numerous other salts, in particular NaCl, KC1, CaC12, MgCl2, SrCl2, Na2SO4, K2SO4, NaH2BO3, KH2BO3... Thus, rather than treating all the impurities in the brine, which are in the majority, the object of the invention is to extract only the desired salt, in this case LiCl, and therefore to significantly improve all of the technical and economic parameters presented in Table 1.

[0018] [Table 1]

[0019] Parameters considered Unit State of the art

[0020] Extraction yield % 30 - 50%

[0021] Lithium

[0022] Consumption of brine m 3 / t Li2CO3125 - 900 extracted

[0023] Fresh water consumption m 3 / t Li2CO316 - 100

[0024] Process floor area hectare 400 - 2000

[0025] Displaced salts (NaCl, MgCl2, tonne / t Li2CO350 - 500

[0026] CaSO4...) Chemical Reagents (HCl, kg / t Li2CO3100 - 4000 H2SO4, CaO)

[0027] Heat (NG or Diesel) kWh / t Li2CO33 000 - 8500

[0028] Electricity kWh / t Li2CO3500 - 1200

[0029] CO2 emissions tonne / t Li2CO34 - 5

[0030] Time to market years 5 - 6 (minimum) of new capacity kUS$ / (t

[0031] Investment costs, CAPEX 16 - 28 Li2CO3 / year)

[0032] Operating costs, OPEX US$ / t Li2CO33 050 - 4600

[0033] To do this, the invention aims to implement a liquid-liquid extraction solution by presenting an organic formulation allowing the selective extraction of di-ionic lithium salts (salts with one anion and one monovalent cation) in the presence of numerous other dissolved inorganic compounds, chosen, at least, from alkalis, alkaline earths, halogens, sulfates, carbonates and other borates.

[0034] The use of liquid-liquid extraction for the selective extraction of lithium from natural or artificial brines has been studied for many years.

[0035] Thus, US patent 3,306,712 describes the use of alcohols or ketones for the selective extraction of LiCl, LiBr or LiI from CaCl2 brine with regeneration of the solvent with water in the presence of urea to extract the co-extracted CaCl2.

[0036] Gabra and Torma [1] studied the extraction of

[0037] LiCl, NaCl, KCl and CaCl2 by many alcohols showing partition coefficients (Li, Na), (Li, K) and (Li, Ca) of less than 3.21, 2.9 and 9.17 respectively. The alcohol with the best performance is n-butanol despite a relatively high co-absorption of CaCl2- Overall, the solubility of LiCl increases with a decrease in the molar mass of the alcohol but this molar mass must be increased to reduce the solubility of the alkaline earth chlorides, MgCl2 and CaCl2-

[0038] Bukowsky and Uhlemann [2] proposed the use of solvent mixtures of isopentyl alcohol associated with 2-ethyl-1,3-hexane, diisopropyl ether or diethyl ether in order to greatly reduce the co-extraction of alkaline earth chlorides, but this is to the detriment of the extraction of LiCl with products which are ultimately too soluble in water.

[0039] US Patent 3,793,433 proposed the solvent extraction of lithium using halogenated p-diketone and trioctylphosphine oxide (TOPO) in benzene with acid regeneration (0.15 N HCl). Separation factors (SF) greater than 1000 are given relative to other alkali metals Na + , K + , Rb + and Cs + but this extractant extracts alkaline earth metals Mg much more favorably 2+ and that 2+ than lithium (SF < 0.07) making the selective extraction of lithium impossible from any natural brine which always contains alkaline earths.

[0040] The use of acid extractants of the 2-ethylhexylphosphonic acid (D2EHPA) type encounters this same difficulty because although experimental data indicate that the L1-D2EPHA complex has a high selectivity over other monovalent metal ions and that the addition of tributyl phosphate (TBP) has a synergistic effect to increase lithium extraction, these acid extractants preferentially extract alkaline earth metals over alkalis ([3]). Thus, commercial acid extractants MEHPA, D2EHPA, Cyanex 272, PC88A, lonquest 801 or others are not suitable for the selective extraction of lithium in the presence of alkaline earth metals.

[0041] Gao & al [4] looked at the use of imidazolium-based ionic liquids with carbon chains of 4 to 9 carbons in the presence of tri-isobutyl phosphate (TIBP). The formation of the complex [Li.2TIBP] + org was established with acid regeneration by cation exchange H+ / Li + but, the lithium extraction phase is done by cation exchange of the ionic liquid (C4min + ) / Li + which does not allow extraction performance to be maintained over time by decomposition of the ionic liquid.

[0042] Patent CN106498184 proposes the use of N-methyl-N-(N'-2-ethylcarbonyl-ethylpyrrole)hexafluorophosphate as ionic liquid. The patent does not provide any information on the conditions for extraction and desorption of LiCl.

[0043] Another approach has been to study neutral organophosphorus extractants in the presence of the co-extraction agent Iron (III). Thus, the TBP / methyl isobutyl ketone (MIBK) / FeCl3([5]) system has attracted attention due to the extractability of the Li couple +FeC14~ in the presence of neutral extractants with oxygen donors. The implementation of a liquid-liquid extraction process with this lithium extraction ternary was thus evaluated ([6]). It appears that its implementation is complex due to the need to avoid the loss of Fe 3+ hydrophilic by maintaining an aqueous environment with a high concentration of chloride anion Cl~ and acid (to avoid the precipitation of Fe(OH)3( S) ) in the washing and back-extraction phases (1 t HCl / t LiCl). In addition, NaOH is used to regenerate the formulation before extraction (2 t NaOH / t LiCl). As a replacement for TBP, other neutral extractants have been studied, such as N,N-bis(2-ethylhexyl) acetamide (N523) ([!])•

[0044] To avoid the use of iron (III), Zhou et al ([8]) proposed the use of sodium phosphomolybdate with heteropolyacid structure as a co-extraction agent in association with TBP / MIBK. This approach allows for Na exchange + / Li + in the extraction phase. A washing step is then implemented via a 2M mixture of LiCl + NaCl (10 / 90) in order to purge the K impurities +and Mg by cation exchange. Then, the back-extraction step is carried out with 0.24 M HCl acid to obtain an acid effluent of LiCl. Finally, the organic phase must be neutralized using 0.26 M NaOH to allow its regeneration before reuse. This new liquid-liquid extraction process by cation exchange over its four phases of extraction, washing, back-extraction and regeneration appears to be theoretically functional but requires excellent operational control of the potential discharges of different forms of potentially toxic molybdenum and presents high costs of chemical reagents.

[0045] US2022 / 274956A1 proposes the use of three-dimensional calixpyrroles to be able to encapsulate a salt, in particular LiCl in the presence of NaCl and KCl for both solid-liquid and liquid-liquid extraction applications. There is no information on the impact of the presence of alkali metals on this extraction to know if this solution is really selective for lithium.

[0046] Thus, no liquid-liquid extraction solution is described in the literature which is both selective for lithium in the presence of alkali and alkaline-earth metals, without the use of chemical reagents and industrializable in the short term (non-toxic, inexpensive products, sufficiently insoluble in water, etc.).

[0047] The present invention therefore relates to a hydrophobic organic liquid composition for the selective extraction of a di-ionic lithium salt comprising a lithium cation and an anion complementary to the lithium cation chosen in particular from Cl~, , Bd, CLT, NOs-, HCO3- from a lithium-rich brine to be treated, said composition comprising: (A) at least one compound extracting the lithium cation, chosen from the compounds of formula: in which:

[0048] - RI and R2, identical or different, are, whatever their position on a nitrogen atom, independently chosen from linear or branched C1-C12 alkyl, aryl, C4-C8 cycloalkyl; or

[0049] - RI and R2, taken together with the nitrogen atom which carries them, form a five-, six-, seven- or eight-membered cycle;

[0050] - R3 is chosen from hydrogen, linear or branched C1-C8 alkyl, C4-C8 cycloalkyl, C2-C6 alkoxyalkyl and alkoxyalkylaryl;

[0051] - R4 is chosen from hydrogen, linear or branched C1-C3 alkyl;

[0052] - R5 is chosen from hydrogen, linear or branched C1-C3 alkyl;

[0053] - R6 is chosen from hydrogen, linear or branched C1-C3 alkyl;

[0054] (B) at least one organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation; and

[0055] (C) at least one hydrophobic polar organic diluent having a flash point at atmospheric pressure greater than 60°C, preferably greater than 75°C, more preferably greater than 90°C.

[0056] Di-ionic lithium salt means a lithium salt comprising a lithium cation Li + , carrying a single positive charge, as well as a mono- or polyatomic anion carrying a single negative charge, such as for example the monoatomic anion Cl or the polyatomic anion N03~.

[0057] The lithium cation extracting compound may have a molar mass of at least 450 g / mol, preferably at least 550 g / mol.

[0058] The lithium cation extracting compound may have a Log K complexation constant for this cation in methanol at 25°C, at least equal to 1, preferably greater than 2.

[0059] The lithium cation extracting compound may exhibit a negative enthalpy variation during the complexation of the lithium cation, AH, associated with an absolute value of the ratio of the enthalpy variation during the complexation of the lithium cation AH to the entropy variation during the complexation of the lithium cation, AS, at the temperature T=298K, |AH / (TAS)| greater than 2, preferably greater than 5.

[0060] These values ​​of enthalpy variation and entropy variation during the complexation of the lithium cation make it possible to obtain a value of variation of the free energy AG which is more influenced by the enthalpic component rather than by its entropic component. This makes it possible to have a lithium cation extracting compound which can extract the lithium cation cold and be regenerated hot.

[0061] The lithium cation extracting compound may have a melting temperature of less than 200°C, preferably less than 50°C and more preferably less than 25°C.

[0062] In a particular embodiment:

[0063] - RI and R2 may be, whatever their position on a nitrogen atom, independently chosen from methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, 2-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, 2-ethylhexyl, phenyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl; or,

[0064] - RI and R2, taken together with the nitrogen atom which carries them, can form a pyrrolidine, piperidine, azepane or azocane ring;

[0065] - R3 may be selected from hydrogen, methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, 2-methylbutyl, 2-ethylpropyl, n-hexyl, cyclohexyl, methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl and -Clb-O-Clb-Phenyl; and

[0066] - R4, R5 and R6 can be hydrogen or methyl,

[0067] RI and R2 being advantageously chosen from butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl or phenyl in the case where the brine to be treated has a calcium concentration greater than 10 g / L and / or the selectivity Li + / That 2+ is privileged; and

[0068] RI and R2 being advantageously chosen from iso-propyl, iso-butyl, sec-butyl, tert-butyl, iso-pentyl, 2-methylbutyl, 2-ethylpropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl or RI and R2, taken together with the nitrogen atom which carries them, form a pyrrolidine, piperidine, azepane or azocane ring in the case where the brine to be treated has a calcium concentration of less than 10 g / L and / or the selectivity Li + / N / A + is preferred. The lithium cation extracting compound can be chosen from:

[0069]

[0070] The organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation, may have a pKa in water at 25°C of at least 9, preferably at least 10.5 and preferably lower than the pKa of water at 25°C, or at least lower than 15 at 25°C and whose solubility in water at 25°C is less than 0.01 mol / l. The organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation may be a compound of formula (B): (B) in which: − at least one of the radicals R B , R C and R D , identical or different, is a halogen atom or an electron-withdrawing group chosen from the following group: F, Cl, Br; C m F 2m+1 with m ≤ 4, where m is a non-zero integer; CF2CF2C p H 2p+1 with p ≤ 4, where p is an integer; CF2C p H 2p+1 with p ≤ 4, where p is an integer; CH2C p F 2p+1with p ≤ 4, where p is an integer; OCH2CF3; C(=O)CF3; C m H n F p Cl q Br s with m ≤ 4, where n, p, q, s are integers of which at least p, q or s is non-zero; C(=O)OC m H 2m+1 with m ≤ 4, where m is an integer; and C(=O)C m H 2m+1 with m ≤ 4, where m is an integer; − the radical(s) R A , R B , R C , R D and R E remaining are chosen, identical or different, from the following non-electro-withdrawing radicals: H; CH3; CH2CH3; CH2CH2C p F 2p+1 with p ≤ 4, or p is an integer; C m H 2m-1 with m ≤ 10, where m is an integer greater than 1; and C m H 2m+1 with m ≤ 10, where m is a non-zero integer; where only one of the radicals R A to R E can be one of these last two radicals C m H 2m-1 etc m H 2m+1; and − X is chosen from the following radicals: .OH ; ; ; ; ; ; where R A , R B , R C , R D and R E , identical or different, are as defined above in formula (B), where R' and R'', identical or different, are chosen from the following radicals: H; C n H 2n-1 with n ≤ 4, where n is an integer greater than 1; C n H 2n+1 with n ≤ 4, where n is a non-zero integer; CH2CH2C p F 2p+1 with p ≤ 4, or p is an integer; CH2C p F 2p+1 with p ≤ 4, where p is an integer; CF2C p H 2p+1 with p ≤ 4, where p is an integer; CF2CF2C p H 2p+1 with p ≤ 4, where p is an integer; C m F 2m+1 with m ≤ 4, where m is a non-zero integer; C m H n F p Cl q Br s with m ≤ 4, where n, p, q, s are integers of which at least p, q or s is non-zero; and where R''' is chosen from the following radicals: Cm H 2m+1 with m ≤ 20, where m is an integer; C m H 2m-1 with m ≤ 20, where m is an integer greater than 1; C m H n F p Cl q Br s with m ≤ 10, where n, p, q, s are integers of which at least p, q or s is non-zero; CH2CH2C p F 2p+1 with p ≤ 4, or p is an integer; CH2C p F 2p+1 with p ≤ 4, or p is an integer; CF2C p H 2p+1 with p ≤ 4, where p is an integer; CF2CF2C p H 2p+1 with p ≤ 4, where p is an integer; C m F 2m+1 with m ≤ 4, where m is a non-zero integer; and an aryl radical of formula (b): (b) where R A , R B , R C , R D and R E, identical or different, are as previously defined in formula (B). In particular, in the compound of formula (B) X may represent: . Compound (B) may be represented by the formula: (C): or (D): , in which R''' is chosen from the following radicals: C m H 2m+1 with m ≤ 20, preferably ≤ 15 where m is an integer; C m H 2m-1 with m ≤ 20, where m is an integer greater than 1; C m H n F p Cl q Br s with m ≤ 10, where n, p, q, s are integers of which at least p, q or s is non-zero; and an aryl radical of formula (b): (b) where R A , R B , R C , R D and R E , identical or different, are as defined in formula (B) above. In a particular embodiment, the radical R''' may be n-C7H 15 , n-C9H 19 , nC 11 H 23 or nC 13 H 27.The at least one lithium cation extracting compound may be present in the composition at a concentration of 0.15 to 1 mol / L, preferably 0.3 to 1 mol / L, more preferably 0.45 to 1 mol / L. The ratio of the molar concentration of the at least one organic, protic, hydrophobic compound solvating the complementary anion of the lithium cation to the molar concentration of the at least one lithium cation extracting compound may be 1 to 10, preferably 1.5 to 5, and more preferably 2 to 4. The hydrophobic polar organic diluent may have a viscosity at 20°C of less than 5 mPa.s, preferably less than 2 mPa.s. Preferably, the hydrophobic polar organic diluent is a polar aromatic diluent. This aromatic diluent may be selected from 2-chlorobromobenzene, 1,2-dibromobenzene, 2-bromotoluene or 3,4-dibromotoluene.The hydrophobic organic liquid composition may have a density at 20°C greater than 1.20 kg / L, preferably greater than 1.25 kg / L, more preferably greater than 1.30 kg / L, for a viscosity at 20°C less than 50 mPa.s, preferably less than 25 mPa.s, for a brine to be treated with a density at 20°C at least 0.05 kg / L lower. The hydrophobic organic liquid composition may have a density at 20°C greater than 1.25 kg / L, preferably greater than 1.30 kg / L, more preferably greater than 1.35 kg / L, for a viscosity at 20°C less than 30 mPa.s, preferably less than 15 mPa.s, for a brine to be treated with a density at 20°C at least 0.15 kg / L lower. The viscosity of the diluent and the hydrophobic organic liquid composition is measured using an Anton Paar Lovis 2000 module viscometer. The sample is introduced into a capillary of well-known diameter.The measurement is carried out using a steel ball that will circulate more or less quickly in the capillary depending on the greater or lesser viscosity of the sample. The device detects the ball and measures the time it took to travel through the capillary at a certain degree of inclination. Having been previously calibrated using certified liquids, the device then provides the viscosity measurement in mPa.s. The density is measured using an Anton Paar DMA 4100M electronic density meter over a temperature range of 0 to 100°C. The points used here are those at 20°C. This device is described, for example, in patents EP3012612 and EP3101409.

[0071] The sample is introduced into a glass tube of precise volume. This begins to vibrate. The period of the assembly (tube + liquid) is determined. The instrument subtracts this period from the reference period of the empty glass tube to determine the period of the liquid present in this glass tube. A chart translating the period as a function of the density makes it possible to determine the density of the said liquid.

[0072] The present invention also relates to a compound chosen from the compounds of formula: The present invention also relates to the use of the hydrophobic organic liquid composition described above in a lithium salt extraction process, said process comprising a step of mixing, at a first temperature, the hydrophobic organic liquid composition and the brine to be treated, a step of separating the hydrophobic organic liquid composition loaded with lithium salt and the treated brine, and a step of regenerating the hydrophobic organic liquid composition by treating the hydrophobic organic liquid composition loaded with lithium salt with treatment water, said regeneration step being carried out at a second temperature, higher than the first temperature, the difference between the first temperature and the second temperature being 30 to 150°C, preferably 50 to 100°C, more preferably 60 to 80°C.

[0073] One of the objectives of the invention is to be able to selectively extract LiCl from lithium-rich continental brines found in the Andean highlands of Chile, Argentina and Bolivia or Tibetan highlands in China. Figure 1 shows the compositions measured in mmol / L of about twenty of these natural brines with an average density of 1.22 kg / L. According to these compositions, the Li / Na selectivity appears to be the first decisive factor followed by the Mg / Li, Ca / Li and SCy / Li selectivities. The compositions according to the invention can also treat these brines after reconcentration by solar or other evaporation.

[0074] There are ion selective electrodes (ISE) based on a polyvinyl chloride (PVC) membrane, which are selective for lithium for the measurement of lithium concentration in aqueous solutions or in blood. In particular, the series of ionophores I to VIII is presented by Kamenica & al ([9]). Lithium ionophore I: N,N′-diheptyl-N,N′,5,5-tetramethyl-3,7-dioxanonanediamide, or 2,2′-[(2,2-dimethyl-1,3- propanediyl)bis(oxy)]bis[N-heptyl-N-methyl-Acetamide, ETH 149, CAS: 58821-96-8 Lithium ionophore II: N,N,N′,N′-tetraisobutyl-cis-cyclohexane-1,2-dicarboxamide, ETH 1644, CAS: 80547-18-8 Lithium ionophore III: N,N-dicyclohexyl-N′,N′-diisobutyl-cis-cyclohexane-1,2-dicarboxamide, ETH 1810, CAS: 99281- 50-2 Lithium ionophore IV: N,N,N′,N'-tetracyclohexyl-5-ethyl-5-butyl-3,7-dioxanonanediamide, or 2,2′-[(2-butyl-2-ethyl-1,3-propanediyl)bis(oxy)]bis[N,N-dicyclohexylacetamide], ETH 2137, CAS: 108083-23-4 Lithium ionophore V: 1,4,7,10-tetracyclododecane, or 12-crown-4, CAS: 294-93-9 Lithium ionophore VI: 6,6-dibenzyl-1,4,8,11-tetraoxa- cyclotetradecane, CAS: 106868-21-7 Lithium ionophore VII: 2-(6-dodecyl-1,4,8,11- tetraoxacyclotetradec-6-yl)ethyl diethyl phosphate, CAS: 106868-29-5 Lithium ionophore VIII: 2,2′-[[2-[[2-(Dicyclohexylamino)- 2-oxoethoxy]methyl]-2-ethyl-1,3-propanediyl]bis(oxy)]- bis[N,N-dicyclohexyl-acetamide], CAS: 133338-85-9 Lithium ionophore X: N,N,N′,N'-tetracyclohexyl-5,5-dimethyl-3,7-dioxanonanediamide, or 2,2′-[(2,2-Dimethyl-1,3-propanediyl)bis(oxy)]bis[N,N-dicyclohexylacetamide], ETH 2015, CAS: 108444-70-8,

[0075] Experimental Part A volume of organic formulation is brought into contact with a volume of salt water (O / A ext=1), then stirred at 800 rpm at 23°C for 30 minutes. After stopping stirring, the two phases are left to settle for 5 to 30 minutes at 23°C, then the aqueous and organic phases are removed. The organic phase then follows a back-extraction phase at 80 or 90°C with demineralized water (A / O desext=5) via stirring for 35 minutes at 800 rpm. After stopping stirring, the two phases are left to settle for 10 to 15 minutes at 80 or 90°C, then the two resulting waters are analyzed by ion chromatography. The extraction and back-extraction (regeneration) parameters are presented in Table 2. [Table 2] Extraction Parameters Regeneration Phase Phase Dragon SK-0330 Hettich lab Apparatus Pro Hettich lab technology MKR 13 technology MKR 13 Ratio A / OA / O = 1 A / O ≈ 5.2 Volumes used A = 1.5 mL A = 5 mL Temperature 22.8°C – RT 91-93.7°C Stirring time 30 min - 1h 35 min Stirring speed 500-800 RPM 800 RPM Settling time 5 -30 min ≤ 15 min Depending on the equipment available, the orbital stirrer or the shaker are used for extraction tests. On the contrary, only the shaker is used for regeneration because it is the only device that can heat up.The results are used after recalculation of the analytical values, corrected for the A / O factor and the carryover (calculated in relation to magnesium). For greater precision, only the back-extraction measurements are taken into account. Analytical equipment: Metrohm ion chromatography, Cation column: Metrosep C6-150 / 4.0 (ref 6.1051.420) Anion column: Metrosep A supp S 250 / 4.0 (Ref 6.1006.530). 15 Below are some definitions necessary for the characterization of the results of the following experimental designs. Extraction yields ^ ^ ^ ^ and extraction ^ ^ ^ ^ ^ , the distribution coefficients (D M ), the separation factors (^^ (Li / M) ) for the extraction of lithium Li + compared to metal M n+ and the extractant usage rate (%Use(M)) are given by equations (1), (2), (3), (4) and (5) respectively: 30

[0076]

[0077] Where represent respectively the initial and final concentrations in the aqueous extraction and back-extraction phase, and in the organic phase for the M ion n+ . are the volume ratios between the organic and aqueous phases respectively in extraction and de-extraction phases.

[0078] Furthermore, since a temperature-modulated liquid-liquid extraction solution is sought, the equilibrium constant K eq (T) must be strongly dependent on the operating temperature and therefore predominantly enthalpically (AH) as explained in the Arrhenius equation (5). ) That I

[0079] Can be presented in its linear form:

[0080] Experimental plan n°1: Extraction of salts by ionophores of Lithium II, IV, V, VIII and X. This involves carrying out extraction tests, in duplicate, of aqueous solutions of respectively LiCl, NaCl, KC1, and CaC12 in pure bodies, in the presence of an excess of MgC12, for several ionophores via a liquid organic formulation composed of [CE] o l r g ~ 45 mmol / L of ionophore (Cationic Extractant CE) for 10 equivalents of anionic solvate (AS), i.e. 450 mmol / L of AT— (3,5— bis (trifluoro-methyl)phenyl)octanamide (CigHigFgNO, CAS 1974318-14-3), all dissolved in 1,2-dichlorobenzene (2DCB) (C6H4C12, CAS 95-50-1).

[0081] The aqueous / brine phases to be tested in extraction were created in the laboratory from demineralized water and pure salts (> 99.9%). They are defined in Table 3.

[0082] [Table 3]

[0083] This choice of high salinities and chloride doping were considered to be able to push the extractability of salts by ionophores to their maximum and potentially reduce the uncertainty linked to the analysis of the extracted ions for these products chosen for their potential low capacity to extract Na, K and Ca chloride salts. The extraction and de-extraction protocol previously presented is maintained for each of these tests. The extraction results are given in the

[0084] Table 4.

[0085] [Table 4]

[0086] It appears that Li VIII tripodant allows much higher salt extraction than extractants II, IV and X, and that lithium extraction is very low for extractants II and V, which are considered lithium ionophores for ion-selective electrodes.

[0087] These results show that:

[0088] 1. Just because an ionophore is used in a cation-selective electrode does not mean that it can also be used in liquid-liquid salt extraction. Thus, the Li II ionophore (ETH 1644) achieves very low salt extraction ranging from 0.25 to 1.10 mmol / L, which is still less than 2.6% extractant usage rate.

[0089] 2. Just because an ionophore is selective for a cation in the application of a selective electrode, does not mean that it will also be selective for this cation in liquid-liquid extraction. Thus, the Li V ionophore, even if it is presented as a lithium ionophore, in fact largely prefers to extract NaCl compared to LiCl with an extraction 205 times higher for NaCl.

[0090] 3. The Li IV and Li X ionophores, which are of very similar structural composition, have similar performances with extractant usage rates for lithium of 19.2% and 15% respectively and for sodium of 5.37% and 7.09% respectively. On the other hand, the Li VIII ionophore has high extractant usage rates of 83% (Li), 62.6% (Na) and 76% (Ca) in extraction of pure salts.

[0091] 4. The Li VIII ionophore, which is the “tripod” version of the Li IV and Li X ionophores, which are “dipod”, allows a use of the extractant 4.33 times higher for the extraction of LiCl compared to the latter.

[0092] Experimental plan n°2: Multi-salt extraction by 14-crown-4 ether-crowns This involves carrying out extraction tests in multi-salts of chloride Li, Na, K, Mg, and CaC12 with a water composition that can be close to continental salar water, that is to say here with an excess of sodium, for several ionophores via a liquid organic formulation composed of [CE] o l r g ~ 80 mmol / L of ionophore (Cationic Extractant CE) for 3 equivalents of anionic solvate (AS), i.e. 240 mmol / L of N- (3,4-dichlorophenyl)-octanamide (C14H19C12NO, CAS 730-25-6), all dissolved in 2-chlorobromobenzene (2CBB) (CgîhBrCl, CAS 694-80-4).

[0093] The brine to be tested in extraction was created in the laboratory from demineralized water and pure salts (> 99.9%). The composition of the measured water (ES-001) is shown in Table 5.

[0094] [Table 5]

[0095] It is representative of a brine at the well outlet for the implementation of a direct lithium extraction (DLE) solution, or rather, direct lithium salt extraction (DLSE).

[0096] The extraction and de-extraction protocol previously presented is maintained.

[0097] Given the level of extraction of Li V, based on a crown ether, we focused the study on crown ethers based on 14-crown-4. In addition to Li VI and Li VII, the two ionophores below were tested and also characterized as lithium selective electrodes.

[0098] Dibenzo-14-crown-4 (DB14C4), CAS: 14174-06-2

[0099] 6-[2-(benzyloxy)ethyl]-6-dodecyl-14-crown-4 (BzO Li VII),

[0100] CAS: 106868-24-0

[0101] The results are summarized in Table 6.

[0102] [Table 6]

[0103] It appears that the four ionophores based on 14-crown-4 ethers achieve only very modest LiCl extraction with less than 2.25% extractant usage (or loading) rate with less than 1.8 mmol / L of extracted LiCl for an 80 mmol / L extractant formulation (EC).

[0104] On the other hand, the Li VIII ionophore confirms its efficiency with 45.4% usage rate (or loading) of the extractant with 36.30 mmol / L of LiCl absorbed by this formulation. In addition, the separation factors (SE) are very good with “infinite” values ​​for Li / Mg and Li / Ca, 469 for Li / K and 153 for Li / Na.

[0105] In summary, it appears that in a single contact at ratio (O / A)ext = 1, 28.5% of the lithium and less than 5% for the other ions are extracted with Li VIII, on a liquid-liquid extraction stage, as illustrated in Table 7 via analyses of the composition of the treated brine.

[0106] [Table 7]

[0107] If an ionic balance is carried out from the composition of the formulation de-extracted at 80°C in five volumes of demineralized water, the result is even more favorable with regard to Na impurities + , K + , Mg 2+ and that 2+ which are then practically not extracted, while retaining 25.4% of extracted lithium, as can be seen in Table 8.

[0108] [Table 8]

[0109] 2I

[0110] Note the strong competition between Li+ and Ca for the extractant since experiment 1 had 34.55 mmol / L of CaCl2 absorbed alone while this trial did not see any CaCl2 absorption in the presence of lithium. Another potential reason may be due to an eq.AS here of 3 instead of 10 for the previous experiment.

[0111] Experimental plans 1 and 2 having been carried out with respectively 10 and 3 equivalents of anionic solvate AS, the impact of this parameter on the extraction capacity in LiCl, NaCl and CaCl2 of a formulation at 80 mmol / L of ionophore Li VIII was examined in order to increase the usage rate of the extractant.

[0112] Experimental plan n°3: Extractions and stoichiometric coefficient of solvation of Cl-

[0113] This involves carrying out extraction tests of aqueous solutions of LiCl, NaCl and CaCl2 respectively in pure bodies, in duplicate, in the presence of an excess of MgCl2, for 4 liquid organic formulations composed of [CE] o l r g « 80 mmol / L of ionophore Li VIII for respectively 1, 3, 5 and 10 equivalents of anionic solvate (AS), i.e. 80, 240, 400 and 800 mmol / L of N- (3,5-bis(trifluoromethyl)-phenyl)octanamide, all dissolved in 1,2-dichlorobenzene (2DCB).

[0114] The different aqueous phases and brines to be tested in extraction were created in the laboratory from demineralized water and pure salts (> 99.9%). Their compositions are indicated in Table 9.

[0115] [Table 9]

[0116] The extraction and de-extraction protocol previously presented is maintained for each of these tests.

[0117] The results are summarized in Tables 10 to

[0118] 13 and Figures 2 and 3.

[0119] [Table 10] It appears that the anionic solvate AS plays its role as a facilitator of salt transfer to the organic phase because the quantity of LiCl, NaCl or CaCl2 extracted increases with eq.SA. Thus, the extraction yield (Figure 2) and the extractant usage rate (Figure 3) increase with eq.SA but a large difference in performance is observed at equilibrium between test 3.1 and tests 3.2 and 3.3, showing significant selectivity for lithium.

[0120] It appears that the very high selectivity of the Li VIII ionophore makes it possible to generally find the same level of lithium extraction performance whether with or without the presence of sodium compared to experiments 1 and 2.

[0121] From the data in these tables and figures, it is clear that the equilibrium constants K eq are very different (Essays 3.1 / 3.2: 68 / 1 and Essays

[0122] 3.1 / 3.3: 161 / 1). Thus, the proposed formulation is well suited to the selective extraction of LiCl in the presence of NaCl and / or CaCl2 due to the strong difference in equilibrium constants K eq and the non-extraction of magnesium and potassium ions.

[0123] Experimental plan n°4: Influence of the O / A ratio ex t on the extraction of salts.

[0124] This involves carrying out extraction tests on a multi-salt brine with O / A ex t increasing from 0.1 to 10, for a liquid organic formulation with 3 equivalents of anionic solvate (AS), i.e. N- (3,4-dichlorophenyl)-octanamide (C14H19CI2NO, CAS 730-25-6) for, of ionophore Li VIII, all dissolved in 2-chlorobromobenzene (2CBB) (CgîhBrCl, CAS 694-80-4).

[0125] The brine to be tested in extraction, representative of a real lithium-rich brine, with the presence of the sulfate ion, was created in the laboratory from demineralized water and pure salts (> 99.9%). Its salinity is 425 g / L and its composition is shown in Table 14.

[0126] [Table 14]

[0127] The tested O / Aext are 0.1; 0.25; 0.5; 1; 2;

[0128] 4 and 10. These tests make it possible to evaluate the influence of this ratio on the extraction yields of the different ions.

[0129] The extraction and de-extraction protocol previously presented is maintained for each of these tests with the exception of the O / A ex t given above.

[0130] The results are summarized in Tables 15 to 17 and Figure 4.

[0131] [Table 15]

[0132]

[0133] Note the total absence of extraction for the K, Mg and SO4 ions 2 ~.

[0134] These experiments show the relevance of the tested formulation to achieve a selective extraction of LiCl in the presence of other alkali and alkaline earth salts.

[0135] From these data, a distribution curve of LiCl between organic and aqueous phases at constant temperature and pressure is also obtained in Figure 5, which we call the LiCl absorption isotherm at 20°C for the excess chloride concentration studied.

[0136] Experimental plan n°5: Calorimetric measurements in methanol at 25°C

[0137] In order to validate the complexing capacity of the Li VIII ionophore, for these Li cations + , That 2+ and Na + , a study by isothermal titration calorimetry (ITC) of their complexation was carried out.

[0138] Experiments were performed on an ITC200 (GE Healthcare) and a TAM 2277 (TA Instruments) at room temperature. The analytical solvent was methanol (Chromasolv®, Sigma-Aldrich) and the ionic strength was set to 0.1M by Et4NCl. Stock solutions of Li (0.1232 mo / L), Ca (0.1300 mol / L) and Na (0.1074 mol / L) were prepared from chloride salts and their concentrations were determined by ICP analysis.

[0139] On the ITC200, each titration consisted of 26 additions of 1.5μL of metal stock solution into the 0.2022 mL analytical cell containing the ionophore ligand Li VIII under stirring.

[0140] On the TAM 2277, each titration consisted of 17 additions of 15 μL of metal stock solution into the ImL analysis cell containing 0.8 mL of solution incorporating the ionophore ligand Li VIII under stirring.

[0141] For each study, several titrations were carried out to determine the best analysis conditions, then replicates (at least 3) were carried out.

[0142] The ionophore extractants CE00 (Li VIII) and CE40 form complexes of 1:1 stoichiometry (M n+ :CE, M n+ = Li + , N / A + or that 2+ ). The complexation equilibrium and the complexation constant in methanol (K Me0 H) associated are defined as follows:

[0143] M n+ + CE <==> MCE, K Me0H = [MCE] / [M][CE]

[0144] (M = Li, Na or Ca and CE= Li VIII= CE00 or CE40)

[0145] The average results obtained for the cationic extractants CE00 and CE40 are given in Table 18.

[0146] [Table 18] a Calculated from the relation AG = -RT ln(K) (T=298K,

[0147] R=8.314 J / mol / K) b Calculated from the relationship AG = AH - TAS (T=298K).

[0148] The heat of reaction could not be determined for NaCl with the equipment used due to too low complexation. These thermodynamic parameters (AH, AS) indicate an exothermic complexation reaction for lithium and calcium with a negative enthalpic component AH and a predominant one in the calculation of the free enthalpy AG, with for example here, at the temperature T=298K, a ratio |AH / (TAS)| of 7 and 2.8 respectively for the complexation of lithium.

[0149] It follows that the ability of CEOO and CE40 ionophores to complex these cations is highly temperature dependent. Therefore, hot water back-extraction was considered.

[0150] Experimental plan n°6 Extraction at 80°C of a formulation loaded with salts

[0151] For a liquid organic formulation composed of [CE] o lr g = 0.3 mol / L of CEOO ionophore (Li VIII) and 3 equivalents of anionic solvate (AS), i.e. 0.9 mol / L N- (3,4-dichlorophenyl)-octanamide (C14H19CI2NO, CAS 730-25-6), all dissolved in 2-chlorobromobenzene (2CBB) (CgîhBrCl, CAS 694-80-4), it is a question of carrying out an extraction at 23°C on a multi-salt brine, then of evaluating the back-extraction of the previously absorbed salts, by contact with demineralized water at 80°C for increasing A / Odesext ranging from 0.02 to 5.

[0152] The brine used in extraction, representative of a real lithium-rich brine, was created in the laboratory from demineralized water and pure salts (> 99.9%). After analysis, its salinity was 360 g / L and its composition is shown in Table 19.

[0153] The A / Odesext tested at 80°C are 0.02; 0.033;

[0154] 0.05; 0.067; 0.1; 0.2; 0.5 and 5. These tests make it possible to evaluate the influence of this ratio, and therefore of the quantity of demineralized water used, on the extraction yields of the different ions.

[0155] The extraction and de-extraction protocol previously presented is maintained for each of these tests with the exception of the A / Odesext given above and the O / Aext given below.

[0156] First, a single contact extraction with ratio (O / A) is implemented ex t = 1.43 with 95 mL of organic phase and 66.5 mL of brine.

[0157] The liquid-liquid extraction performance is illustrated in Table 20 via the analyses of the composition of the treated brine.

[0158] [Table 20]

[0159]

[0160] If an ionic balance is carried out from the composition of the formulation de-extracted at 80°C in 5 volumes of demineralized water, the result is more favorable with regard to the extraction of lithium which goes from 69.3% to 74.5% while the impurities remain very little extractable, except for calcium, in very low initial concentration, as we see in Table 21.

[0161] These results indicate the formulation's ability to provide an initial effective separation of lithium from other ions.

[0162] The results of the demineralized water extraction at 80°C are summarized in Tables 22 and 23 and Figures 6 and 7.

[0163] *Within the limits of analysis precision.

[0164] From these results, a distribution curve of LiCl between organic and aqueous phases at constant temperature and pressure is also obtained in Figure 8, which we call the LiCl back-extraction isotherm with demineralized water at 80°C.

[0165] By combining Figures 5 and 8, two lithium partition curves at 20°C and 80°C are obtained in Figure 9 for the implementation of the LiCl separation and purification process.

[0166] The difference between these isotherms expresses the possible respiration of the formulation for the implementation of the temperature-modulated liquid-liquid extraction process of LiCl. These partition isotherms of LiCl allow the construction of the associated McCabe-Thiele for the determination of the necessary number of unit stages to be implemented both in the extraction phase and in the back-extraction phase for two given operating lines, as illustrated in Figure 10.

[0167] Experimental plan n°7: Extractability of nitrate salts, other di-ionic salts, LiNO3, NaNO3 and tri-ionic Ca(NO3)2.

[0168] This involves carrying out extraction tests of aqueous solutions of LiNO3, NaNO3 and Ca(NO3)2 respectively in pure bodies, for variable concentrations, in the presence or not of an excess of Mg(NO3)2, for a liquid organic formulation composed of mmol / L of ionophore Li VIII for 3 equivalents of anionic solvate (AS), i.e. 750 mmol / L of N- (3,4-dichlorophenyl)-octanamide (C14H19CI2NO, CAS 730-25-6), all dissolved in 2-chlorobromobenzene (2CBB) (CgïhBrCl, CAS 694-80-4).

[0169] The different aqueous phases and brines to be tested in extraction were created in the laboratory from demineralized water and pure salts (> 99.9%). Their compositions are indicated in Table 24.

[0170] [Table 24]

[0171] The extraction and de-extraction protocol previously presented is maintained for each of these tests.

[0172] For contact at 20°C with (0 / A)ext= 1, for each of these initial water compositions, five distribution isotherms at 20°C were obtained representing the relative concentrations of the different salts between the organic extract and the aqueous phases at equilibrium, as shown in Figure 11.

[0173] It appears that the saturation of the formulation at 0.25 mol / L is quickly reached for the doped LiNO3 and Ca(NO3)2 salts while the NaNO3 is weakly absorbed. This demonstrates that as for the chloride salts, the di-ionic nitrate salts are also extractable.

[0174] Experimental plan n°8: Evolution of the density and viscosity of formulations with Li VIII

[0175] The aim was to evaluate the impact of the relative concentrations of cationic extractant and anionic solvate on the density and viscosity at 20°C of the formulation. To do this, different formulations with Li VIII, N-(3,4-dichlorophenyl)-octanamide, all dissolved in 2-chlorobromobenzene (2CBB) were produced for different relative concentrations of CE and AS.

[0176] The results obtained are summarized in Figures 12 and 13.

[0177] It appears that the density decreases linearly with the concentration in CE at iso equivalence AS. It is also noted that for the treatment of brines at 1.22 kg / L of density, it is not possible to go beyond a certain concentration in CE if, for example, the formulation must remain at a density greater than 1.27 kg / L.

[0178] It appears that the viscosity of the formulation with increasing concentrations of this Li VIII extractant can become limiting for its industrial implementation in these liquid-liquid extraction systems, in particular those where gravity decanters are used, which see decantation being all the more difficult as the continuous phase is viscous.

[0179] Other compounds were therefore examined in order to identify extractants that maintain good selectivity and extraction for lithium while generating less viscosity. In particular, liquid extractants are interesting to study because they are potentially more soluble and generate less formulation viscosity.

[0180] Compounds of formula:

[0181] The synthesis of the compounds of interest is carried out in three successive stages.

[0182] Step 1: Synthesis of the secondary amine

[0183] In a clean, dry flask, introduce the ketone (10 mmol, 1 eq), the solvent (17 Vol), the amine (45 mmol, 4.5 eq) then the reagent(s). Depending on the reagent, heat if necessary. The conversion is monitored by TLC with the disappearance of the starting ketone. Evaporate the solvent (and sometimes the residual amine) under reduced pressure. Filtration if necessary on Fontainebleau sand then addition of methanol (12 Vol). Addition in portions of NaBH4 (30 mmol, 3 eq) if necessary, stirring for 1-15 h at RT.

[0184] Purification on silica gel if necessary. (DCM to DCM / ethyl acetate). Yield: 20-77%

[0185] Step 2: Synthesis of chloroacetamide

[0186] In a flask, introduce the previously formed amine (10 mmol, 1 eq), dichloromethane (3 Vol, 15 eq), triethylamine (30 mmol, 3 eq). Add cold and under argon atmosphere chloroacetyl chloride (20-25 mmol, 2-2.5 eq). Stir at room temperature for 5-24 h. Add 2 Volumes of water and carry out 2 counter-extractions of the aqueous phase with 2 Volumes of DCM. Concentrate the organic phase on a rotary evaporator.

[0187] Purification of the product on a silica gel column (eluent

[0188] DCM 100%). Yield: 30-70% Step 3: Synthesis of the compound of interest

[0189] In a three-necked flask, introduce NaH (3.5-4 eq) into 10 volumes of anhydrous THF. Heat the medium to reflux under argon. Hot introduction of the triol solubilized in 10 volumes of THF then the synthesized chloroacetamide, solubilized in 15-20 volumes of THF. Stir the medium at reflux for 1-24 hours. Neutralize the medium by adding 10 volumes of water. Perform two counter-extractions of the aqueous phase with 5 volumes of DCM. Then perform one or two washes of the organic phase with 5 volumes of water. Concentrate the organic phase on a rotary evaporator.

[0190] Purify the crude product obtained by chromatography on silica gel (eluent: heptane / ethyl acetate). Yields are generally between 50-70%.

[0191] Table 25 shows the formulas of the synthesized compounds, with Li VIII being renamed CE00.

[0192] [Table 25]

[0193] Tables 26 and 27 present the characteristics of the synthesized compounds.

[0194] Experimental plan n°9: Synthesis of extractants and densities of formulations

[0195] As the different extractants CE00 to CE39 were synthesized, the impact of the extractant on the density of formulations with 3 equivalents of anionic solvates and molar concentrations of CE of 0.2 and 0.3 mol / L respectively was examined on 3 to 5 mL of formulation.

[0196] A relatively logical trend was obtained. The higher the molar mass of the extractant, the more negative its impact on the density of the formulation.

[0197] Thus, lowering the molar mass of the extractant is interesting with the limitation of its solubility in water.

[0198] Experimental plan n°10: Viscosity of a formulation with a low molar mass extractant

[0199] Since the viscosity measurement requires 15 to 20 mL of formulation, it was chosen to synthesize a low molar mass extractant of relatively easy synthesis to obtain more than 50 grams of Et-NPipéridine (CAS n° 405264-17-7) (1H NMR: 4.02 (s, 6H), 3.53 - 3.40 (m, 6H), 3.34 (s, 12H), 1.54 (dd, J = 20.0, 14.4 Hz, 18H), 1.38 (d, J = 7.6 Hz, 2H), 0.81 (t, J = 7.6 Hz, 3H)) for the production of formulations integrating 1.5 to 5 grams of this extractant. Beyond its low molar mass, this product proved to be an oil, which allows us to predict that the formulations tested are representative of the minimum viscosities that can be obtained with this family of tripod extractants.

[0200] The results obtained are summarized in Figure 15.

[0201] It appears that the viscosity is reduced on average by 53%, which makes it possible to approach CE concentrations of 400 mmol / L, giving a limit of 20 centipoise at 20°C, i.e. a gain in extraction capacity of around 33% compared to formulations with the Li VIII / CE00 ionophore.

[0202] Experimental design no. ll: Extraction performance of compounds of interest

[0203] This involves implementing exactly the experimental plan no. 1 already presented but for new cationic extractants CE01 to CE39.

[0204] Some of the extraction results obtained are given in Table 28.

[0205] [Table 28]

[0206] These results show that:

[0207] 1. For all compounds, except Et-

[0208] N (Morpholine), EC39, a high rate of extractant usage with respect to lithium is maintained with variability of Keq (Li) but K's eq (Na) and K eq (It) always low,

[0209] 2. A liquid extractant is very accessible by the functionalization of the amide (RI, R2),

[0210] 3. The use of cyclic and / or branched chains in RI, R2 promotes Li / Na selectivity and therefore the extraction of Li + / N / A + .

[0211] 4. The use of linear alkyl chains with more than 4 carbons promotes Li / Ca selectivity and therefore the extraction of Li + / That 2+ .

[0212] 5. The use in R3 of an elongated or branched alkyl chain or of an electron donor group promotes the rate of use of the extractant.

[0213] 6. Replacing one hydrogen at R4, R5 and / or R6 with at least one short-chain alkyl improves lithium extraction capacity while lowering the melting temperature of the extractant.

[0214] Following these promising results, work continued on the study of extraction phases at 20°C and de-extraction at 80°C on multi-salt brines for formulations incorporating the targeted extractants, some of which are presented below.

[0215] Experimental plan n°12: Implementation of a formulation integrating CE21 to demonstrate the possible use of these various tripodants in selective extraction of LiCl. For a liquid organic formulation composed of [CE] o l rg = 80 mmol / L of ionophore CE21 and 4 equivalents of anionic solvate (AS), i.e. 320 mmol / L of N-(3,4-dichlorophenyl)-octanamide (C14H19CI2NO, (CAS 730-25-6), all dissolved in 2-chlorobromobenzene (2CBB) CgîhBrCl, CAS 694-80-4), it is a question of carrying out an extraction at 23°C on a multi-salt brine, then of evaluating the back-extraction of the previously absorbed salts, by putting it in contact with demineralized water at 80°C for A / Odesext of 0.2 and 1. These tests make it possible to evaluate the influence of this ratio on the back-extraction yields of the different ions.

[0216] The brine used in extraction, representative of a real lithium-rich brine, was created in the laboratory from demineralized water and pure salts (> 99.9%).

[0217] After analysis, it has a salinity of 286.5 g / L and its ionic composition is indicated in Table 29.

[0218] The extraction and de-extraction protocol previously presented is maintained for each of these tests with the exception of the A / Odesext given above.

[0219] First, a single contact extraction with ratio (O / A) is implemented ex t = 1 with 10 mL of organic phase and 10 mL of brine. The liquid-liquid extraction performance is shown in Table 30.

[0220] [Table 30]

[0221] The results of the de-extraction with demineralized water at 80°C are summarized in Tables 31 and 32.

[0222] For comparison, by replacing CE21 with CE00, the Li VIII ionophore, the extraction performance obtained is illustrated in Table 33. Lithium extraction performance is improved, from 13.2% to 33.1%, but above all, calcium extraction is lowered from 14.3% to 3.5%. It should also be noted that the separation factors (SF) are significantly improved on all cations. The same work on other tripods has given, for example, for CE11, a liquid extractant, a lithium extraction yield of 30.1% and calcium of 4.5%, while others are even better. Example: For a liquid organic formulation composed of ^4 Y 44 ^ 4^& ?@A = 0.34 mol / L of ionophore CE11 and 3 equivalents of anionic solvate (AS), i.e. 1.02 mol / L of N-(3,4-dichlorophenyl)-octanamide (C 14 H 19Cl2NO, CAS 730-25-6), all dissolved in 2-chlorobromobenzene (2CBB)(C6H4BrCl, CAS 694-80-4), it involves implementing a liquid-liquid extraction process of LiCl by temperature modulation between a multi-salt brine to be treated at 20°C and demineralized water at 80°C by using 4 stages of mixer-decanters in extraction at 20°C and a stirred column with 3 theoretical stages to carry out the extraction at 80°C.

[0223] The LiCl extraction phase is carried out with an (O / A)ext of 1.1 at 20°C and the LiCl deextraction phase is carried out with an (0 / A) deS ext from 10 to 80°C.

[0224] The brine used in extraction is a reconstituted brine based on a published reference composition from the Salar de Maricunga in Chile. It was created in the laboratory from demineralized water and pure salts (> 99.9%).

[0225] After analysis, it has a salinity of 306.4 g / L and its composition is indicated in Table 34.

[0226] The associated McCabe-Thiele diagram is given in Figure 16.

[0227] The process diagram considered to illustrate this implementation is shown in Figure 17.

[0228] The four extraction stages are carried out by the four mixers in series [la] to [4a] associated with the four decanters in series [Idc] to [4d], of which [Idc] is a centrifugal decanter. The heat exchangers [le] and [2e] serve both to heat and cool the organic phase and the extraction water respectively. Finally, the hot countercurrent extraction column is shown in [le].

[0229] The material balance obtained for a production equivalent to 12,285 tonnes of LiCl per year is given in Table 35 for 21.5 tonnes of water / h supplied with [Al].

[0230] The lithium extraction and production efficiency here is 93%.

[0231] This basic material balance can be significantly improved in terms of the purity of the desorbed LiCl by implementing intermediate washing steps of the organic phase after the extraction phase of LiCl from the brine. Thus, a single washing step of the organic phase after extraction with (A / O)i a v = 0.05 allows to lower the sodium concentration Na + Desextract from 0.486 mol / L to 0.076 mol / L (SF = 3330) and calcium Ca 2+ from 0.272 mol / L to 0.026 mol / L (SF = 865) without major degradation of the lithium production yield which goes from 93% to 90.5% for a (O / A) ex t of 1.1. Experimental design n°13: Introduction of other extractants of this family and associated experimental results of Li / Na selectivity. Compounds CE40 to CE43 were synthesized and integrated into various formulations and experiments.

[0232] Extractants CE40 to CE43 are all in solid form and are unknown in the literature.

[0233] This involves carrying out selective Li extraction tests. + / N / A + , in duplicate, of an aqueous solution composed of 0.1 mol / L of LiCl, 0.1 mol / L of NaCl, in the presence of an excess of 1.5 mol / L of MgC12, for the ionophores CE00, CE02, CE27, CE40 and CE43 via a liquid organic formulation composed of 0.1 mol / L of Cationic extractant CE for 8 equivalents of anionic solvate (MSA), i.e. 0.8 mol / L of N- (3,4- bis (dichlorophenyl)octanamide (C14H19C12NO, CAS No. 730-25- all dissolved in l-bromo-2-chlorobenzene (2CBB)

[0234] (C6H4BrCl, CAS No. 694-80-4) The salty aqueous phases to be tested in extraction were created in the laboratory from demineralized water and pure salts (> 99.9%).

[0235] The extraction and de-extraction protocol presented above is maintained for each of these tests.

[0236] The experimental results are presented in Tables 38 and 39 below.

[0237] It appears here that the "head" of the extractant, R3, plays a significant role with respect to the selectivity of the cationic extractant for lithium compared to sodium and that the amine chosen via RI & R2 has little impact on the sodium extraction rate which always remains low in the presence of lithium. Thus, the CE extractant can be judiciously chosen, depending on the ionic composition of the lithium-rich brine to be treated, to allow maximum technical and economic performance.

[0238] Experimental plan n°14: Feasibility of using a variety of anionic solvates for the selective extraction of LiCl using the extractant CE02.

[0239] This involves carrying out LiCl extraction tests from an aqueous solution composed of 0.05 mol / L of LiCl, in the presence of an excess of 1.5 mol / L of MgC12, for twelve anionic solvates (MSA) present in a liquid organic formulation composed of 0.1 mol / L of the cationic extractant CE02 for 5 equivalents of anionic solvate (MSA), i.e. 0.5 mol / L, all dissolved in 1,2-dichlorobenzene (DCB) (C6H4CI2, CAS No. 90-50-1).

[0240] The saline aqueous phase to be tested in extraction was created in the laboratory from demineralized water and pure salts (> 99.9%).

[0241] The extraction and de-extraction protocol presented above is maintained for each of these tests.

[0242] The experimental LiCl extraction rates and deprotonation pKas are presented for each of the MSAs in Table 40 below. It is demonstrated here that the use of a lithium extracting molecule, according to the invention, CE02, combined with one or other of the anion solvating molecules (Cl~ here), among those previously described, once dissolved in a polar aromatic solvent, here 1-bromo-2-chlorobenzene (2CBB), makes it possible to ensure good extraction of LiCl from an aqueous phase to an organic phase by liquid-liquid route according to the invention.

[0243] References

[0244] [1] Gabra & Torma - Hydrometallurgy, 1978, 3, pp. 23-33

[0245] [2] Bukowsky & Uhlemann - Separation science and Technology, 1993, 28(6), pp. 1357-1360

[0246] [3] Hano et al. - Solvent Extraction and Ion Exchange, 1992, 10(2), pp. 195-206

[0247] [4] D. Gao et al. - Journal of Chemical Engineering of Japan, 2016, Vol. 49, No. 2, p. 104-110

[0248] [5] Zhou et al - J. Chem. Eng. Data 2011, 56, pp. 3518-3522

[0249] [6] Zhou & al - Ind. Eng.Chem. Res., 2012, 51, pp. 12926- 12932

[0250] [7] Hui-fang & al - Hydrometallurgy, 2016, 160, pp. 1-5

[0251] [8] Zhou & al. - ACS Sustainable Chem. Eng., 2019, 7, 9, pp. 8885-8892

[0252] [9] Kamenica & al. - Sensors, 2017, 17, pp 2430

Claims

Claims

1. – Hydrophobic organic liquid composition for the selective extraction of a di-ionic lithium salt comprising a lithium cation and an anion complementary to the lithium cation chosen in particular from Cl-, I-, Br-, CN-, NO3-, HCO3- from a lithium-rich brine to be treated, said composition comprising: (A) at least one lithium cation extracting compound, chosen from the compounds of formula: in which: − R1 and R2, identical or different, are, whatever their position on a nitrogen atom, independently chosen from C1-C alkyl 12linear or branched, aryl, C4-C8 cycloalkyl; or − R1 and R2, taken together with the nitrogen atom which carries them, form a five-, six-, seven- or eight-membered ring; − R3 is chosen from hydrogen, linear or branched C1-C8 alkyl, C4-C8 cycloalkyl, C2-C6 alkoxyalkyl and alkoxyalkylaryl; − R4 is chosen from hydrogen, linear or branched C1-C3 alkyl; - R5 is chosen from hydrogen, linear or branched C1-C3 alkyl; - R6 is chosen from hydrogen, linear or branched C1-C3 alkyl; (B) at least one organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation; and (C) at least one hydrophobic polar organic diluent having a flash point at atmospheric pressure greater than 60°C, preferably greater than 75°C, more preferably greater than 90°C.

2. - Hydrophobic organic liquid composition according to claim 1, characterized in that the lithium cation extracting compound has a molar mass of at least 450 g / mol, preferably at least 550 g / mol.

3. - Hydrophobic organic liquid composition according to one of claims 1 and 2, characterized in that the lithium cation extracting compound has a Log K complexation constant for this cation in methanol at 25°C at least equal to 1, preferably greater than 2.

4. - Hydrophobic organic liquid composition according to one of claims 1 to 3, characterized in that the lithium cation extracting compound has a negative enthalpy variation during the complexation of the lithium cation, AH, associated with an absolute value of the ratio of the enthalpy variation during the complexation of the lithium cation AH to the variation of the entropy during the complexation of the lithium cation, AS, at the temperature T=298K, |AH / (TAS)| greater than 2, preferably greater than 5.

5. - Hydrophobic organic liquid composition according to one of claims 1 to 4, characterized in that the lithium cation extracting compound has a melting temperature of less than 200°C, preferably less than 50°C and more preferably less than 25°C.

6. - Hydrophobic organic liquid composition according to one of claims 1 to 5, characterized in that: - RI and R2 are, whatever their position on a nitrogen atom, independently selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, 2-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, 2-ethylhexyl, phenyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl; or - RI and R2, taken together with the nitrogen atom which carries them, form a pyrrolidine, piperidine, azepane or azocane ring; - R3 is selected from hydrogen, methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, 2-methylbutyl, 2-ethylpropyl, n-hexyl, cyclohexyl, methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl and -CH2-O-CH2-Phenyl; and - R4, R5 and R6 are hydrogen or methyl, RI and R2 being advantageously chosen from butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl or phenyl in the case where the brine to be treated has a calcium concentration greater than 10 g / L and / or the selectivity Li + / That 2+ is privileged; and RI and R2 being advantageously chosen from iso-propyl, iso-butyl, sec-butyl, tert-butyl, iso-pentyl, 2-methylbutyl, 2-ethylpropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl or RI and R2, taken together with the nitrogen atom which carries them, form a pyrrolidine, piperidine, azepane or azocane ring in the case where the brine to be treated has a calcium concentration of less than 10 g / L and / or the selectivity Li + / N / A + is privileged.

7. - Hydrophobic organic liquid composition according to one of claims 1 to 6, characterized in that the lithium cation extracting compound is chosen from:

8. - Hydrophobic organic liquid composition according to one of claims 1 to 7, characterized in that the organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation, has a pKa in water at 25°C of at least 9, preferably at least 10.5 and preferably lower than the pKa of water at 25°C, or at least lower than 15 at 25°C and whose solubility in water at 25°C is less than 0.01 mol / 1.

9. - Hydrophobic organic liquid composition according to claim 8, characterized in that the organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation is a compound of formula (B): (B) in which: − at least any one of the radicals R B , R C and R D , identical or different, is a halogen atom or an electron-withdrawing group chosen from the following group: F, Cl, Br; C m F 2m+1with m ≤ 4, where m is a non-zero integer; CF2CF2C p H 2p+1 with p ≤ 4, where p is an integer; CF2C p H 2p+1 with p ≤ 4, where p is an integer; CH2C p F 2p+1 with p ≤ 4, where p is an integer; OCH2CF3; C(=O)CF3; C m H n F p Cl q Br s with m ≤ 4, where n, p, q, s are integers of which at least p, q or s is non-zero; C(=O)OC m H 2m+1 with m ≤ 4, where m is an integer; and C(=O)C m H 2m+1 with m ≤ 4, where m is an integer; − the radical(s) R A , R B , R C , R D and R E remaining are chosen, identical or different, from the following non-electro-withdrawing radicals: H; CH3; CH2CH3; CH2CH2C p F 2p+1 with p ≤ 4, or p is an integer; C m H 2m-1 with m ≤ 10, where m is an integer greater than 1; and C m H 2m+1with m ≤ 10, where m is a non-zero integer; where only one of the radicals R A to R E can be one of these last two radicals C m H 2m-1 etc m H 2m+1 ; And − X is chosen from the following radicals: .OH; where R A , R B , R C , R D and R E , identical or different, are as defined above in formula (B), where R' and R'', identical or different, are chosen from the following radicals: H; CnH2n-1with n ≤ 4, where n is an integer greater than 1; C n H 2n+1 with n ≤ 4, where n is a non-zero integer; CH2CH2C p F 2p+1 with p ≤ 4, where p is an integer; CH2C p F 2p+1 with p ≤ 4, or p is an integer; CF2C p H 2p+1 with p ≤ 4, where p is an integer; CF2CF2CpH2p+1 with p ≤ 4, where p is an integer; CmF2m+1 with m ≤ 4, where m is a non-zero integer; C m H n F p Clq Br s with m ≤ 4, where n, p, q, s are integers of which at least p, q or s is non-zero; and where R''' is chosen from the following radicals: CmH2m+1 with m ≤ 20, where m is an integer; CmH2m-1 with m ≤ 20, where m is an integer greater than 1; C m H n F p Cl q Br s with m ≤ 10, where n, p, q, s are integers of which at least p, q or s is non-zero; CH2CH2C p F 2p+1 with p ≤ 4, or p is an integer; CH2C p F 2p+1 with p ≤ 4, or p is an integer; CF2CpH2p+1 with p ≤ 4, where p is an integer; CF2CF2C p H 2p+1 with p ≤ 4, where p is an integer; C m F 2m+1 with m ≤ 4, where m is a non-zero integer; and an aryl radical of formula (b): (b) where R A , R B , R C , R D and R E, identical or different, are as previously defined in formula (B).

10. – Hydrophobic organic liquid composition according to claim 9, characterized in that in the compound of formula (B) X represents: .

11. – Hydrophobic organic liquid composition according to claim 10, characterized in that the compound (B) is represented by the formula: (C): or (D): , in which R''' is chosen from the following radicals: CmH2m+1 with m ≤ 20, preferably ≤ 15 where m is an integer; C m H 2m-1 with m ≤ 20, where m is an integer greater than 1; C m H n F p Cl q Br s with m ≤ 10, where n, p, q, s are integers of which at least p, q or s is non-zero; and an aryl radical of formula (b): (b) where R A , R B , R C , R D and R E, identical or different, are as defined in formula (B) in claim 8.

12. – Hydrophobic organic liquid composition according to claim 11, characterized in that the radical R''' is n-C7H 15 , n-C9H 19 , nC 11 H 23 or n- C 13 H 27.

13. - Hydrophobic organic liquid composition according to one of claims 1 to 12, characterized in that the at least one lithium cation extracting compound is present in the composition at a concentration of 0.15 to 1 mol / L, preferably 0.3 to 1 mol / L, more preferably 0.45 to 1 mol / L.

14. - Hydrophobic organic liquid composition according to claim 13, characterized in that the ratio of the molar concentration of the at least one organic, protic and hydrophobic compound, solvating the complementary anion of the lithium cation to the molar concentration of the at least one compound extracting the lithium cation is from 1 to 10, preferably from 1.5 to 5 and more preferably from 2 to 4.

15. - Hydrophobic organic liquid composition according to one of claims 1 to 14, characterized in that the hydrophobic polar organic diluent has a viscosity at 20°C of less than 5 mPa.s, preferably less than 2 mPa.s.

16. - Hydrophobic organic liquid composition according to one of claims 1 to 15, characterized in that it has a density at 20°C greater than 1.20 kg / L, preferably greater than 1.25 kg / L, more preferably greater than 1.30 kg / L, for a viscosity at 20°C less than 50 mPa.s, preferably less than 25 mPa.s, for a brine to be treated with a density at 20°C at least 0.05 kg / L lower.

17. - Hydrophobic organic liquid composition according to one of claims 1 to 15, characterized in that it has a density at 20°C greater than 1.25 kg / L, preferably greater than 1.30 kg / L, more preferably greater than 1.35 kg / L, for a viscosity at 20°C less than 30 mPa.s, preferably less than 15 mPa.s, for a brine to be treated with a density at 20°C at least 0.15 kg / L lower.

18. - Compound selected from the compounds of

19. - Use of the hydrophobic organic liquid composition according to one of claims 1 to 17 in a lithium salt extraction process, said process comprising a step of mixing, at a first temperature, the hydrophobic organic liquid composition and the brine to be treated, a step of separating the hydrophobic organic liquid composition loaded with lithium salt and the treated brine, and a step of regenerating the hydrophobic organic liquid composition by treating the hydrophobic organic liquid composition loaded with lithium salt with treatment water, said regeneration step being carried out at a second temperature, higher than the first temperature, the difference between the first temperature and the second temperature being 30 to 150°C, preferably 50 to 100°C, more preferably 60 to 80°C.

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