Simulated moving bed lithium chromatographic separation process

Abstract

The present invention relates to a method for the chromatographic separation of lithium contained in a brine by simulated moving bed, said method comprising a step of fractionating the brine into at least two separate streams, each of the brine streams being loaded into each injection point of a simulated moving bed (SMB) chromatography, then percolated, finally the lithium is recovered by means of at least two withdrawal points.

Description

Title of the invention: Method for the chromatographic separation of lithium by simulated moving bed Technical field

[0001] The invention relates to a new method for the chromatographic separation of lithium contained in a brine by simulated moving bed, said method making it possible to significantly improve the operation of a simulated moving bed by obtaining an optimal separation of lithium with high productivity, while limiting the consumption of eluent. The method according to the present invention comprises in particular a step of loading the lithium contained in a brine into at least two injection points of a simulated moving bed (SMB) chromatography, said brine being previously divided into at least two separate flows and each flow injected into at least two injection / loading points, followed by a step of recovering the lithium from at least two withdrawal points. State of the art

[0002] Lithium has become a key resource in the energy transition in 20 years. Thanks to its low molar mass and small size, it is the optimal metal for the design of rechargeable batteries. Lithium is extracted either from lithium-bearing rocks or from brines. There are several types of brines that can be used for lithium extraction, namely Salar brines, geothermal brines, and hydrocarbon brines.

[0003] Many processes for recovering lithium from brines are already known. The classic process is mainly based on the variation in solubility of salts as a function of concentration. Thus, the brines are evaporated naturally in lagoons and the Sodium Chloride (NaCl) will crystallize until the Sodium is at the solubility limit, but also the Magnesium and Calcium, which are themselves crystallized by the addition of lime and carbonate.

[0004] However, this process is long, requires large quantities of reagent and dries out the extraction sites which are already areas of water stress. In addition, a substantial part of the Lithium precipitates during the different crystallization stages which results in a low yield of around 50%.

[0005] To overcome these drawbacks, lithium-specific adsorbents have been developed. They are based on microporous crystalline structures. As an example, we can cite patent FR 3053264 which describes the production of a synthetic mineral adsorbent based on aluminum oxide, as well as patent application US2020010926 which describes a synthetic hybrid adsorbent coupling a resin anionic and a crystalline aluminum oxide deposit. Other titanium-based adsorbents as described in patent application WO2023083065 may also be used.

[0006] Some of these materials can be synthesized by precipitation in an aqueous medium of aluminum sulfate, sodium aluminate and at least one lithium source. The presence of lithium during precipitation makes it possible to define the pore size specific to lithium capture. However, these materials require a minimum lithium content in the medium, in particular to avoid a collapse of their crystalline structure, then leading to the loss of lithium capture capacity. Thus, today thanks to these different adsorbents, it is possible to directly extract lithium from brines by chromatographic separation.

[0007] Conventionally, the brine is percolated onto the adsorbent of interest, then the adsorbent is rinsed and desorbed with a lithium-poor solution. The lithium-rich fraction is recovered and follows the successive steps until the production of lithium salt.

[0008] Various technical solutions have already been described, including the chromatographic separation process comprising a single column which is loaded and then unloaded by successively carrying out the steps of saturation, rinsing and displacement of the lithium-charged solution.

[0009] Other processes have been developed to improve the productivity and efficiency of adsorbents. For example, the 3-column carousel process can be cited, which is carried out by following a circular permutation system of 3 adsorbent beds: 2 columns are placed in series and percolated with the solution containing the lithium to be captured, such that the first column reaches saturation of the capture when the second column captures the leak from the first. A third column is being rinsed and the lithium is displaced. After saturation, the first column replaces the third, which is rinsed, and then the lithium is displaced by the washing solution. The column in the second position moves to the first position, and the column after washing replaces the column previously in the second position.

[0010] Beyond these co-current capture and release processes, those skilled in the art have developed processes based on the principle of counter-current washing.

[0011] Thus, Broughton et al. (US2985589) proposed the principle of the simulated moving bed (SMB). This system allows countercurrent chromatography by simulating the movement of the solid phase included in a multitude of columns connected in series by a set of valves which will move the injection and extraction points of the solvents in a regular and sequenced manner. The solvent and the adsorbent move in opposite directions, which maximizes the separation effect between the adsorbed molecules and the non-adsorbed molecules.

[0012] Several developments have been proposed to improve the principle of the moving bed simulated, in particular the SSMB process described by Yoritomi et al. (US4379751) which by dividing the SMB step into sub-steps, each being independent, improves the precision of injection and collection of fractions. Tanimura et al. (JP119784 / 88) proposes ISMB, which is an intermediate process between SMB and SSMB. We can also cite Bailly et al. (FR2785196) which proposes an asynchronous permutation of inputs and outputs allowing a distribution of columns which varies over time (VARICOL).

[0013] Finally, this principle of chromatographic separation by simulated moving bed is already proposed for the extraction and separation of lithium (Martson et al. US 11365128) by describing an SMB carousel of 30 columns distributed over 4 zones.

[0014] Nevertheless, all of these teachings have the disadvantage of low productivity, given the presence of a single adsorption zone and a single desorption zone. However, in the context of the energy transition with increasing needs for Lithium, these processes are not satisfactory from an ecological and environmental point of view but also in terms of productivity.

[0015] There is therefore a need for a chromatographic separation method having improved productivity and overcoming the drawbacks of the prior art. This is the subject of the present invention. Summary of the invention

[0016] Thus, the present invention relates to an improved method for the chromatographic separation of lithium contained in a brine by simulated moving bed, in which a continuous chromatography comprises a multitude of columns connected in series and a multitude of valves arranged so as to isolate and / or permute said columns forming at least four zones, - a zone 1 comprising at least two contiguous columns, an injection point of an eluent and at least two withdrawal points of an extract comprising the separated lithium, said zone 1 being between the injection point of the eluent and the second withdrawal point of an extract 2 located downstream of the first withdrawal point of an extract 1, - a zone 2 between the second extraction point of extract 2 and a brine injection point, - a zone 3 comprising at least two contiguous columns, at least two brine injection points and at least two raffinate withdrawal points, said zone 3 being between the first brine injection point and the second raffinate withdrawal point, located downstream of the first brine injection point, itself located downstream of the first raffinate withdrawal point, and - a zone 4 between the second raffinate withdrawal point and the eluent injection point, wherein said method comprises the following steps: a. Split the brine into at least two separate streams, brine stream 1 and brine stream 2, b. Inject brine stream 1 at the first brine injection point in zone 3 and inject brine stream 2 at the second brine injection point in zone 3, c. Percolating said streams into said contiguous columns of zone 3 and loading the eluent at the eluent injection point, d. Recover and dispose of each raffinate stream at each of the raffinate draw-off points, and e. Recover the separated lithium in each of the extract withdrawal points.

[0017] Thus, unlike the prior art which teaches us the injection / loading of a single brine flow, the present invention by splitting the initial flow into as many brine flows of interest (n brine flows), preferably at least two distinct flows and injecting these into at least two injection points, makes it possible to improve the productivity of the separation of lithium from a brine. Indeed, this makes it possible to maximize the flow rate of treated brine relative to the number of columns while retaining the advantages of the simulated moving bed principle.

[0018] Thus, the brine is injected at at least two injection points, then circulates cyclically and sequentially through a continuous countercurrent adsorption and desorption circuit, and the extracts comprising the separated lithium are recovered at at least two withdrawal points for said extracts, located in zone 1. A first withdrawal point makes it possible to recover a diluted lithium extract 1 and a second withdrawal point, located downstream of the first withdrawal point, makes it possible to recover a concentrated lithium extract 2.

[0019] To achieve this, zone 3 is advantageously divided into at least two sub-zones (zone 3.1 and zone 3.2) each comprising an inlet (point for loading a brine stream) and an outlet (point for withdrawing the raffinate). Thus, within the meaning of the invention, zone 3 comprises at least two sub-zones. According to a variant, zone 3 comprises at most 4 sub-zones.

[0020] Zone 1 is divided into at least two sub-zones (zone 1.1 and zone 1.2) each comprising at least one outlet (extract withdrawal point). Thus, within the meaning of the invention, zone 1 also comprises at least two sub-zones.

[0021] According to a variant of the invention, a sub-zone can be interpreted as a zone. Also, in this context, the chromatography according to the present invention can comprise at least 4+y zones, with y > (greater than or equal to) 2, preferably y is between 2 and 6, each zone comprising a column, and comprising an inlet and an outlet. When the chromatography comprises 6 zones, it comprises a zone 1.1, a zone 1.2, a zone 2, a zone 3.1, a zone 3.2 and a zone 4.

[0022] When the brine is split into two separate flows, the ratio between the volume of the injected brine flow 1 and the injected brine flow 2 is preferably between 1 / 99 and 50 / 50, more preferably between 20 / 80 and 50 / 50.

[0023] According to another object of the present invention, zone 3 of the chromatography may comprise n contiguous columns connected together in series or operating in parallel.

[0024] According to a preferred object of the method according to the invention, zone 3 comprises n contiguous columns, each column comprising a point of injection of a brine flow and a point of withdrawal of the raffinate, in which the method comprises a step in which the brine is split into n distinct flows and each flow is injected into each of the injection points of zone 3, n being between 3 and 5.

[0025] According to another particular embodiment of the invention, zone 3 comprises at least three contiguous columns, two contiguous columns in series comprising a single injection point for a brine stream and a single raffinate withdrawal point, and a third contiguous column also comprising a brine injection point and a raffinate withdrawal point.

[0026] Advantageously, zone 3 comprises three contiguous columns comprising three injection points for a brine stream and three withdrawal points for the raffinate, in which the method comprises a step in which the brine is split into 3 separate streams and injected into each of the injection points of zone 3. In this embodiment, zone 3 thus comprises three inlets allowing the loading of each of the brine streams and three outlets, for removing the raffinate.

[0027] The method according to the present invention therefore comprises a step of injecting or loading the brine, said brine being split into n distinct flows, preferably at least two distinct flows and injected independently of one another into n injection points, preferably at least two injection points located in zone 3. During the injection of each of the flows, each flow of brine is preferably injected simultaneously or sequentially.

[0028] More preferably, the step of loading said flows is carried out simultaneously, making it possible, here again, to improve productivity, by increasing the throughput. However, the start of loading one flow may differ from the start of loading the second flow, as well as the end of loading said flows.

[0029] According to another embodiment of the method according to the invention, the method can also comprise a step of placing in series the multitude of columns forming the chromatography, making it possible in particular to move the chromatographic profile in stabilized mode towards the downstream column in an SSMB type chromatography and ISMB.

[0030] Furthermore, the method according to the invention advantageously comprises a step of recovering a diluted lithium extract 1 at the point of withdrawal of the extract located furthest downstream from zone 1, followed by a step of injecting said diluted lithium extract at the point of injection of the eluent in order to maintain a minimum lithium concentration in the eluent.

[0031] Finally, the method according to the invention can also comprise an additional step of placing in series the multitude of columns forming the chromatography and rinsing said columns.

[0032] According to another object of the invention, the step of recovering each of the lithium extracts, namely a diluted lithium extract 1 and a concentrated lithium extract 2, is carried out simultaneously or separately. Preferably, the step of recovering said extracts is carried out simultaneously, again making it possible to improve productivity. However, the recovery of each of the streams is very preferably simultaneous, during which the start and end of the recovery of the diluted extract and the concentrated extract may differ.

[0033] The method according to the invention can be implemented with all types of brine, however, the brine is preferably chosen from the group consisting of Salar brines, geothermal brines and petroleum brines.

[0034] The method according to the present invention is particularly suitable for known simulated moving bed (SMB) chromatographic separation methods, as well as its variants known under the names SSMB, ISMB, VARICOL. By injecting / charging at least a second brine stream, the method according to the present invention maximizes the inlet flow rate and thus the productivity of the lithium separation process from brines.

[0035] Preferably, the method according to the invention is a simulated moving bed (SMB) chromatographic separation method, in which the number of columns forming the chromatography is at least 6, more preferably at least 8.

[0036] Finally, all types of adsorbents known to those skilled in the art can be used to implement the method according to the invention. By way of example without being limiting, mention may be made of titanium-based adsorbents.

[0037] Other characteristics and advantages will emerge from the detailed description of the invention, the examples and the figures which follow. Brief description of the Figures

[0038] [Fig. 1] schematically represents the method according to the present invention implemented with chromatography according to the principle of simulated moving bed, said chromatography comprising 6 columns, forming 4 zones, (Z1, Z2, Z3, and Z4), zone 3 comprising two contiguous columns, two brine injection points (feed) and two raffinate withdrawal points (raffinate 1 and raffinate 2), zone 1 comprising two contiguous columns, one eluent injection point and two extract withdrawal points comprising the separated lithium (extract 1 and extract 2). At the end of each step, the columns are swapped by one column downstream (6 positions). The process is carried out continuously. Said chromatography thus has 6 successive positions before a complete revolution of the sequential.

[0039] [Fig.2] schematically represents the method according to the present invention implemented with a chromatography according to the principle of simulated moving bed, said chromatography comprising 7 columns, forming 4 zones, (Zl, Z2, Z3, and Z4), zone 3 comprising three contiguous columns, two of which are connected in series, two injection points for the brine (feed 1, feed 2) and two withdrawal points for the raffinate (raffinate 1 and raffinate 2), zone 1 comprising two contiguous columns, one injection point for an eluent and two withdrawal points for an extract comprising the separated lithium (extract 1 and extract 2). At the end of each step, the columns are swapped by one column downstream (7 positions). The method is implemented continuously. Said chromatography thus has 7 successive positions before a complete revolution of the sequential.

[0040] [Fig.3] schematically represents the method according to the present invention implemented with a chromatography according to the simulated moving bed principle, said chromatography comprising 7 columns, forming 4 zones, (Zl, Z2, Z3, and Z4), zone 3 comprising three contiguous columns, three brine injection points (feed 1, feed 2, and feed 3) and three raffinate withdrawal points (raffinate 1, raffinate 2, and raffinate 3), zone 1 comprising two contiguous columns, one injection point of an eluent and two withdrawal points of an extract comprising the separated lithium (extract 1 and extract 2). At the end of each step, the columns are swapped by one column downstream (7 positions). The method is implemented continuously. Said chromatography thus has 7 successive positions before a complete revolution of the sequential. Detailed description of the invention

[0041] Definition

[0042] For the purposes of the invention, the term "series" means two contiguous columns connected to each other, in which the most upstream column comprises an injection point, for example an injection point for a brine stream, and the most downstream column comprises a raffinate withdrawal point.

[0043] For the purposes of the invention, “parallel” means two contiguous columns, in which each column comprises an injection point, for example a point injection of a brine stream, and a raffinate withdrawal point.

[0044] Method

[0045] The present invention therefore relates to an improved process for chromatographic separation by simulated moving bed of lithium contained in a brine solution.

[0046] Said continuous simulated moving bed chromatography comprises a multitude of columns connected in series and a multitude of valves arranged so as to isolate and / or permute said columns forming four zones. The chromatography thus comprises a zone 1 between an injection point of the eluent and a point of withdrawal of the extract, a zone 2 between an extract withdrawal point and a brine injection point, a zone 3 between a brine injection point and a raffinate withdrawal point, and a zone 4 between a raffinate withdrawal point and an eluent injection point.

[0047] The extraction point of the extract corresponding to the exit from zone 1 making it possible to recover the extract comprising the lithium separated from the other molecules included in a brine.

[0048] The brine injection point or brine loading point is the inlet through which the brine stream is loaded into the chromatography.

[0049] The raffinate withdrawal point is the exit point for recovering the raffinate. This does not contain lithium, and is considered waste and therefore eliminated.

[0050] Now, the inventors have found that it is possible to significantly improve the operation of a simulated moving bed by obtaining optimal separation of lithium with high productivity, while limiting eluent consumption. To achieve this, the inventors have added a second inlet in zone 3, making it possible to load the chromatography with a second brine stream. This second brine stream is thus loaded into a second injection point in zone 3. In addition, at least one second lithium extract withdrawal point is added in zone 1.

[0051] For this purpose, the inventors have developed a method in which the brine stream is previously split into at least two brine streams, each of the streams being injected into at least two injection points of zone 3. Consequently, at least two raffinate withdrawal points are added downstream of each of the brine stream injection points.

[0052] Furthermore, a second point for drawing off the extract comprising lithium is added downstream of zone 1. Thus, zone 1 comprises an injection point for the eluent located upstream of a drawing off point making it possible to recover and collect a diluted lithium extract 1, itself upstream of a drawing off point making it possible to recover and collect a concentrated lithium extract 2.

[0053] Said diluted lithium extract 1 can advantageously be reinjected in whole or in part into the eluent. The latter is then reinjected at the injection point of the eluent. According to a variant, the diluted lithium extract 1 can be mixed with a solvent before being reinjected into the eluent.

[0054] Thus, in the context of the present invention, zone 1 of the simulated moving bed chromatography comprises at least two contiguous columns, an injection point for an eluent and at least two withdrawal points for the extract comprising the separated lithium, said zone being between the injection point of the eluent and the second withdrawal point of the extract located downstream of the first withdrawal point of the extract.

[0055] According to a particular embodiment, zone 1 comprises at least two contiguous columns each respectively forming a zone 1.1 between the injection point of the eluent and a withdrawal point of an extract 1, corresponding to the diluted lithium extract and a zone 1.2 between the withdrawal point of extract 1 and a withdrawal point of an extract 2, corresponding to the concentrated lithium extract.

[0056] Furthermore, the simulated moving bed chromatography also comprises a zone 3 comprising at least two contiguous columns, at least two brine injection points and at least two raffinate withdrawal points, said zone 3 being between the first brine injection point and the second raffinate withdrawal point, located downstream of the first brine injection point, itself located downstream of the first raffinate withdrawal point.

[0057] According to a particular embodiment, the zone 3 comprises at least two contiguous columns each respectively forming at least one zone 3.1 between the injection point of a brine stream 1 and a raffinate withdrawal point, and at least one zone 3.2 between an injection point of a brine stream 2, said injection point of the brine stream 2 being located downstream of the raffinate withdrawal point 1, and a raffinate withdrawal point 2.

[0058] The method according to the present invention then comprises the following steps: a. Split the brine into at least two separate streams, brine stream 1 and brine stream 2, b. Inject brine stream 1 at the first brine injection point of zone 3 and inject brine stream 2 at the second brine injection point of zone 3, c. Percolating said streams into said contiguous columns of zone 3 and loading the eluent at the eluent injection point, d. Recover and dispose of each raffinate stream at each of the raffinate draw-off points, and e. Recovering the separated Lithium in each of the extraction points of the extracts.

[0059] Thus, the present invention relates to a chromatographic separation process graph of lithium contained in a brine by simulated moving bed, in which a continuous chromatography comprises a multitude of columns connected in series and a multitude of valves arranged so as to isolate and / or permute said columns forming four zones, - a zone 1 comprising at least two contiguous columns, an injection point for an eluent and at least two withdrawal points for an extract comprising the separated lithium, said zone is between the injection point of the eluent and the second withdrawal point of the extract located downstream of the first withdrawal point of the extract, - a zone 2 between the second extract withdrawal point and a brine injection point, - a zone 3 comprising at least two contiguous columns, at least two brine injection points and at least two raffinate withdrawal points, said zone 3 is between the first brine injection point and the second raffinate withdrawal point, located downstream of the first brine injection point, itself located downstream of the first raffinate withdrawal point, and - a zone 4 between the second raffinate withdrawal point and the eluent injection point, said method comprises the following steps: a. Split the brine into at least two separate streams, brine stream 1 and brine stream 2, b. Inject brine stream 1 at the first brine injection point of zone 3 and inject brine stream 2 at the second brine injection point of zone 3, c. Percolating said streams into said contiguous columns of zone 3 and loading the eluent at the eluent injection point, d. Recover and dispose of each raffinate stream at each of the raffinate draw-off points, and e. Recover the separated lithium in each of the extract withdrawal points.

[0060] The method according to the invention thus advantageously makes it possible to maximize the flow rate of treated brine relative to the number of columns while retaining the advantages of the simulated moving bed principle.

[0061] According to an object of the invention, the simulated moving bed chromatography may comprise in zone 3, n contiguous columns, these being able to be connected together in series, or operating in parallel. When the n contiguous columns operate in parallel, these each comprise upstream a point of injection of a brine flow and downstream a point of withdrawal of the raffinate.

[0062] Thus, according to a preferred object, said moving bed chromatography thus comprises n inlets allowing the injection of n brine streams, thus maximizing productivity. Thus, zone 3 preferably comprises n contiguous columns, each column comprising a point for injecting a brine stream and a point for withdrawing the raffinate, in which the method comprises a step in which the brine is split into n separate streams and each stream is injected into each of the injection points of zone 3, n being between 3 and 5.

[0063] When the n contiguous columns are connected in series, the set of n contiguous columns connected in series comprises upstream a single injection point for a brine stream and downstream a single raffinate withdrawal point. According to a particular object, zone 3 can thus comprise n contiguous columns connected in series and at least one additional contiguous column operating in parallel. Zone 3 thus comprises a brine stream injection point and downstream a raffinate withdrawal point and at least one other brine stream injection point and downstream at least one other raffinate withdrawal point.

[0064] According to a particular object of the present invention, the simulated moving bed chromatography may comprise in zone 3 a third contiguous column. Thus, zone 3 comprises at least three contiguous columns, two contiguous columns in series comprising a point of injection of a brine stream and a point of withdrawal of the raffinate, and at least one third contiguous column comprising a point of injection of brine and a point of withdrawal of the raffinate. The third contiguous column comprising a second point of injection of a brine stream and a point of withdrawal of the raffinate being located downstream of said two contiguous columns in series. Thus, zone 3 comprises three contiguous columns, two injection points and two withdrawal points. According to another object, zone 3 comprises four contiguous columns, three injection points and three withdrawal points.

[0065] According to another object of the invention, the simulated moving bed chromatography may comprise in zone 3, a third contiguous column, forming a zone 3.3 comprising a third injection point for a third brine flow, and a third raffinate withdrawal point.

[0066] Zone 3 then advantageously comprises at least three contiguous columns comprising three injection points for a brine stream and three raffinate withdrawal points, in which the brine is split into at least three separate streams and injected into each of the injection points of zone 3, this making it possible to improve both productivity and yield. Thus, zone 3 comprises three contiguous columns, three injection points and three withdrawal points.

[0067] By way of example, the method according to the invention is a simulated moving bed (SMB) chromatographic separation method, in which the number of columns forming chromatography is at least 6, two columns forming a zone 1, one column forming a zone 2, two columns forming a brine loading / injection zone 3 and one column forming a zone 4.

[0068] According to another particular example, the number of columns forming the chromatography is at least 7, the loading zone 3 comprising 3 contiguous columns, operating in parallel and / or connected in series, and the lithium recovery zone 1 comprising 2 contiguous columns.

[0069] When the brine is split into two separate streams, the ratio between the volume of the injected brine stream 1 and the injected brine stream 2 is preferably between 1 / 99 and 50 / 50, more preferably between 20 / 80 and 50 / 50, making it possible to further improve the productivity of the separation process.

[0070] When the brine is split into three separate streams, the ratio between the volume of injected brine stream 1, injected brine stream 2, and injected brine stream 3 is preferably between 1 / 1 / 98 and 1 / 3:1 / 3:1 / 3, more preferably between 10 / 10 / 80 and 1 / 3:1 / 3:1 / 3.

[0071] When the brine is split into n separate flows, the ratio between the volume of each injected brine flow is very preferably 1 / n.

[0072] According to an object of the invention, the steps of injecting the brine streams 1 and 2 are preferably carried out simultaneously or sequentially, very preferably simultaneously, making it possible to improve productivity by increasing the flow rate. However, the start and end of the loading of each of the streams may differ.

[0073] According to a particular embodiment, the method comprises a step of recovering a diluted lithium extract 1 at the point of withdrawal of the extract located furthest downstream of zone 1 and of injecting said diluted lithium extract at the point of injection of the eluent. Thus, said diluted lithium extract is advantageously reinjected in whole or in part into the eluent. The latter is then reinjected at the point of injection of the eluent. According to a variant, the diluted lithium extract can be mixed with a solvent before being reinjected into the eluent.

[0074] Preferably, the recovery of each of the lithium extracts, i.e. at least the diluted lithium extract and the concentrated lithium extract, can be carried out simultaneously or separately, preferably simultaneously.

[0075] Finally, the method according to the invention may comprise an additional step of placing in series the multitude of columns forming the chromatography and rinsing said columns.

[0076] According to a particular embodiment of the invention, in particular when the chromatography is of the SSMB or ISMB type, the method advantageously comprises a step of placing in series the multitude of columns forming the chromatography, which makes it possible to move the chromatographic profile in stabilized mode towards the column in downstream.

[0077] The method according to the invention can be implemented with all types of brine known to contain lithium, preferably, the brine is chosen from the group consisting of Salar brines, geothermal brines and petroleum brines.

[0078] The invention is now illustrated by non-limiting examples of compositions according to the invention and by results. Examples

[0079] Example 1: Process Outside the Invention

[0080] Adsorption desorption of a synthetic Li Na brine on a single column

[0081] This test is carried out according to a method comprising a single column which is loaded then unloaded by successively carrying out the steps of saturation, rinsing and displacement of the solution loaded with lithium (brine).

[0082] The method according to example 1 comprises the following steps: a. Step 1: The brine is charged until the adsorbent is saturated. b. Step 2: The eluent is injected to displace the impregnation brine and elute adsorbed lithium.

[0083] The effluent is then advantageously separated into 3 distinct parts, namely a part 1 rich in Sodium, a part 2 rich in Lithium, and a part 3 comprising the diluted lithium.

[0084] The characteristics of the column are described in Table 1, below.

[0085] [Tables 1] Column length Column diameter Column volume temperature 100 cm 2.5 cm 490 ml 80°C Brine Li Na Saturation flow rate Elution flow rate 0.5 g / 1 92 g / 1 5 BV / h 2 BV / h

[0086] The following results use a dimensionless basis of volumes, namely 1 BV = 1 column volume.

[0087] The results are presented in Tables 2 and 3, below.

[0088] [Tables2] mg / liter resin saturation elution Bm elution Li input 8029 1054 li output 3989 5055 Li fixed 4039 4001 99% Capture % 50%

[0089] [Tables3] g / liter resin saturation elution Bm elution Na inlet 1392389 0 Na outlet 1277287 74820 Na fixed / eluted 115101 74820 65% Capture % 8%

[0090] The inventors thus observe that 50% of the lithium is captured, once it has been completely eluted. In addition, 8% of the sodium is captured, with an elution of only 65% of the Na.

[0091] The inventors then carried out a review of this test. The results are presented in Table 4 below.

[0092] [Tables4] average 0 to 1 BV average 1 to 2 BV average 2 to 6 BV concentration recovery % concentration recovery % Concentration recovery % mg / 1 on output mg / 1 on output mg / 1 on output Li 1277 25.9% 1815 36.9% 458 55.8% Na 73120 97.7% 1700 2.2% 840 1.1% Na / Li 57.27 0.94 1.83

[0093] From the analysis of the elution profile, the inventors cut out 3 zones corresponding to the lithium peak: - From 0 to 1 BV, the inventors note at the output that 25.9% lithium is captured and 97.7% of sodium - From 1 to 2 BV, the inventors note that the Lithium peak represents 36.9% of the eluted lithium and 2.3% of the eluted sodium - From 2 to 6 BV, the inventors observed a significant lithium tail which represents 55.8% of the eluted lithium and a low sodium concentration which represents 1.1% of the eluted sodium.

[0094] With this test, only 22.6% of the lithium involved and 0.1% of the sodium are recovered. The purification effect is good but the recovery efficiency is low. The amount of purified lithium is 0.56 g of lithium per liter per hour.

[0095] Example 2: Process Outside the Invention

[0096] Adsorption desorption of a synthetic Li Na brine on a 3-column carousel

[0097] The 3-column carousel process is carried out according to a circular permutation system of 3 adsorbent beds: 2 columns are placed in series and percolated with the solution containing the lithium to be captured, such that the first column reaches saturation of the capture when the second column captures the leak from the first. A third column is being rinsed and the lithium is displaced. After saturation the first column replaces the third which is rinsed then the lithium is displaced by the washing solution. The column in second position moves to first position and the column after washing replaces the column previously in second position.

[0098] The method more particularly comprises the following steps: a. Step 1: loading of brine, extraction of spent brine (raffinate) on columns 1 and 2 in series b. Step 2: eluent loading on columns 1 and 2 in series, rinsing of column 1, recovery of the brine exhausted in column 2 c. Step 3: Recovery of the impregnation volume of the column containing the end of the sodium peak d. Step 4: Recovery of the lithium peak core e. Step 5: Recovery of the tail of the lithium peak.

[0099] From then on, the 5 steps completed, the entry and exit points are shifted one column downstream. The column in 1st position becomes column 3. The 2nd column position becomes column 1. The column in 3rd position becomes column 2. This cycle is repeated infinitely.

[0100] Finally, the collection from step 3 can be recycled into feed, the collection from step 4 is the lithium-enriched product. Finally, the collection from step 5 corresponds to the diluted lithium which will be used to prepare the eluent.

[0101] The characteristics of the column are described in Table 5, below.

[0102] [Tables5] Column length Column diameter Column volume temperature 100 cm 2.5 cm 490 ml 80°C Brine Li Na Saturation flow rate Elution flow rate 0.5 g / 1 92 g / 1 5 BV / h 2 BV / h

[0103] In this test, the inventors used 3 columns of dimensions identical to those of example 1, implemented using the method described previously.

[0104] The characteristics of the process are described in Table 6 below.

[0105] [Tableauxô] ETAP ES Volume (BV) time (s) Flow rate (BV / h) 1 loading of column 1 in series with 2 with brine 5.15 3158 5.87 2 washing of column 1 in series with column 2 with eluent 0.40 257 5.87 3 elution of column 3 with eluent 0.70 840 3 4 elution of column 3 with eluent 1.60 1920 3 5 elution of column 3 with eluent 1.10 660 6

[0106] The characteristics of the composition of the inputs and outputs are described in Table 7, below.

[0107] [Tables7] inputs (g / L) outputs (g / 1) STEPS Li (mp) Na Cl Li (mp) Na Cl 1 0.511 93.645 147.93 0.058 80.561 127.20 2 0.156 0.040 0.890 0.452 90.421 141.98 3 0.16 0.04 0.89 0.630 51.373 83.42 4 0.16 0.04 0.89 1.024 1.074 7.04 5 0.16 0.04 0.89 0.609 0.116 3.07

[0108] The results are presented in Table 8, below.

[0109] [Tables8] BALANCE Li Na Cl Na / Li % I / O 100% 99% 97% % recovery in outputs 3 16.0% 95.1% 80.0% 81.544 4 59.6% 4.5% 15.4% 1.049 5 24.4% 0.3% 4.6% 0.190

[0110] This test allows to obtain 59.6% of the lithium in the pure fraction 4 against 36.9% for the single column solution. This allows to increase the productivity of the system: the quantity of lithium recovered is 1.17 g / liter of resin and per hour. Fraction 5 is used to prepare the eluent of the following injection. Fraction 3 is recycled in the brine to be treated. [YES] Example 3: Process Outside the Invention

[0112] Adsorption desorption of a synthetic Li Na brine on a 6-column SSMB

[0113] This test is implemented according to the principle of the SSMB, comprising 6 columns of dimensions identical to example 1.

[0114] The principle of the SSMB presents, as the 3-column carousel, a cyclical sequence, namely the following steps: a. Step 1: Recycling loop step of the internal volume of the columns b. Step 2: step of loading the brine onto two contiguous columns of zone 3 in series and recovery of the raffinate at the column outlet; in parallel injection of eluent into column 1 and recovery of the lithium fraction at the column outlet 2. c. Step 3: eluent injection step for rinsing column 1 to column 5 in series, recovery of the remaining raffinate.

[0115] At the end of the step, the entry and exit points are shifted one column upstream. This operation continues indefinitely.

[0116] The characteristics of the column are described in Table 9, below.

[0117] [Tables9] Column length Column diameter Column volume temperature 100 cm 2.5 cm 490 ml 80°C Brine Li Na Saturation flow rate Elution flow rate 0.5 g / 1 92 g / 1 lOBV / h 3 BV / h

[0118] The characteristics of the method implemented are described in Table 10, below. After.

[0119] [Tables10] STAGE ES Volume (BV) time (s) Flow rate (BV / h) 1 Loop stage 0.75 276 9.78 2 Brine feed stage 5.30 1951 9.78 3 Extract extraction stage 2.4 1951 4.42 4 Zones 1 to 3 rinsing stage 0.25 92 9.78

[0120] The characteristics of the composition of the inputs and outputs are described in Table 11, below.

[0121] [Tableauxll] inputs (g / L) outputs (g / l) STEPS Li Na Li Na 2 0.487 91.84 0.150 90.47 3 0.17 0.0 1.123 0.236 4 0.17 0.0 0.150 90.47

[0122] The results are presented in Table 12, below.

[0123] [Tablesl2] BALANCE Li Na Na / Li % E / S 10 3% 103% % recovery in outputs 2+4 / REFFINATE 26% 99.9% 624 3 / EXTRACT 74% 0.1% 0.210

[0124] With the SSMB implementation, it is possible to obtain a very pure lithium fraction, the Na / Li is now 0.191. The extraction yield is 74%, 26% of the lithium remains in the brine because the desorption is incomplete. Indeed, the eluent volume is only 1.95 BV when the carousel volume reaches 3.8 BV. The quantity of lithium recovered is 0.46 g / liter of resin per hour, or 1 / 3 compared to the carousel. The SSMB is of interest for purity but has low yield and low productivity.

[0125] Example 4: Method according to the invention

[0126] Adsorption desorption of a synthetic Li Na brine on an 8-column SSMB.

[0127] This test is carried out according to the method of the present invention comprising 8 columns of dimensions identical to example 1, zone 1 comprising 3 contiguous columns and zone 3, three contiguous columns, including two columns in series, two loading points and two raffinate outlets.

[0128] The characteristics of the column are described in Table 13, below.

[0129] [Tablesl3] Column length Column diameter Column volume temperature 100 cm 2.5 cm 490 ml 80°C Brine Li Na Saturation flow rate Elution flow rate 0.5 g / 1 92 g / 1 3-6 BV / h 2-6 BV / h

[0130] The characteristics of the process are described in Table 14 below.

[0131] [Tables 14] STAGE ES Volume (BV) time (s) Flow rate (BV / h) 1 Loop stage 0.65 390 6 2.1 Brine feed stage 1 3.7 2200 6 2.2 Brine feed stage 2 2.1 2200 3.40 3.1 Extract extraction stage 1 1.30 1680 2.11 3.2 Extract extraction stage 2 0.70 420 6 4 Zones 1 to 3 rinse stage 0.25 92 6

[0132] The characteristics of the composition of the inputs and outputs are described in Table 15, below.

[0133] [Tables 15] inputs (g / L) outputs (g / l) STEPS Li Na Li Na 2 0.510 91.70 0.052 89.70 3 0.15 0.0 2.100 0.110 4 0.15 0.0 0.052 89.70

[0134] The results are presented in Table 16, below. BALANCE Li Na Na / Li % E / S 102% 102% % recovery in outlets 2+4 / Raffinate 9.3% 99.96% 1725 3.1 / extract Li 81 .1 % 0.04% 0.05 3.2 extract for eluent 9.6% 0.01% 0.217

[0136] The inventors have found with the implementation of the process according to the invention that it is possible to obtain a very pure lithium fraction, the Na / Li is now 0.05. The extraction yield is then 81.1%, 9.3% of the lithium is lost in the brine; i.e. a recovery balance on the outputs (excluding recycled extract) of 89.7%.

[0137] The quantity of lithium recovered is 0.81 g / liter of resin per hour, or 2 / 3 compared to the carousel. The process according to the present invention is of interest for purity and further improves lithium recovery thanks to better extraction and has higher productivity than SSMB due to the parallel brine injections.

[0138] Also, the method according to the invention makes it possible to overcome the drawbacks of the prior art and in particular presents a better yield, a productivity close to a 3-column carousel system thanks to the 2 injections in parallel, minimal eluent consumption and maximum recovery thanks to the 2 injections of eluent in parallel.

[0139] Finally, table 17 below presents a comparison of the results obtained with the different tests. Process Example 1 Example 2 Example 3 Example 4 Minimum columns 1 3 and + 4 and + 6 and + Number of columns 1 3 6 8 Extract purity Na / Li 0.94 1.049 0.191 0.05 Productivity gLi / liter adsorbent.H-1 0.56 1.17 0.46 0.81 % recovery 36.9 59.6 74.0 89.7 Eluent consumption liter / g lithium recovered 3.74 2.21 0.98 0.82

[0141] The results demonstrate an improvement in productivity compared to known simulated moving bed processes as well as an improvement in recovery and the level of purity obtained.

Claims

Claims

1. Method for chromatographic separation of lithium contained in a brine by simulated moving bed, in which a continuous chromatography comprises a multitude of columns connected in series and a multitude of valves arranged so as to isolate and / or permute said columns forming at least four zones, - a zone 1 comprising at least two contiguous columns, an injection point for an eluent and at least two withdrawal points for an extract comprising the separated lithium, said zone being between the injection point for the eluent and the second withdrawal point for the extract located downstream of the first withdrawal point for the extract, - a zone 2 between the second extract withdrawal point and a brine injection point, - a zone 3 comprising at least two contiguous columns, at least two brine injection points and at least two raffinate withdrawal points, said zone 3 being between the first brine injection point and the second raffinate withdrawal point, located downstream of the first brine injection point, itself located downstream of the first raffinate withdrawal point, and - a zone 4 between the second raffinate withdrawal point and the eluent injection point, characterized in that said method comprises the following steps: a. Split the brine into at least two separate streams, brine stream 1 and brine stream 2, b. Inject brine stream 1 at the first brine injection point in zone 3 and inject brine stream 2 at the second brine injection point in zone 3, c. Percolate said streams into said contiguous columns of zone 3 and load the eluent at the eluent injection point, d. Recover and dispose of each raffinate stream at each of the raffinate withdrawal points, and e. Recover the separated Lithium from each of the extract withdrawal points.

2. Method according to the preceding claim, characterized in that zone 3 comprises at least three contiguous columns, two contiguous columns in series comprising a brine injection point and a raffinate withdrawal point, and at least a third contiguous column comprising a brine injection point and a raffinate withdrawal point.

3. Method according to claim 1, in which zone 3 comprises n contiguous columns, each column comprising a point of injection of a brine stream and a point of withdrawal of the raffinate, characterized in that the brine is split into n separate streams and each stream is injected into each of the injection points of zone 3, n being between 3 and 5.

4. Method according to one of claims 1 or 2, characterized in that the ratio between the volume of the injected brine flow 1 and the injected brine flow 2 is between 1 / 99 and 50 / 50.

5. Method according to the preceding claim, characterized in that the ratio is between 20 / 80 and 50 / 50.

6. Method according to one of the preceding claims, characterized in that the injection of each brine flow is carried out simultaneously or sequentially.

7. Method according to one of the preceding claims, characterized in that the method also comprises a step of placing in series the multitude of columns forming the chromatography.

8. Method according to one of the preceding claims, characterized in that the method comprises a step of recovering a diluted lithium extract 1 at the point of withdrawal of the extract located furthest downstream from zone 1 and of injecting said diluted lithium extract at the point of injection of the eluent.

9. Method according to one of the preceding claims, characterized in that the method comprises an additional step of placing in series the multitude of columns forming the chromatography and rinsing said columns.

10. Method according to one of the preceding claims, characterized in that the step of recovering each of the lithium extracts, at least one diluted lithium extract and at least one concentrated lithium extract, is carried out simultaneously or separately. 24

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