EP3866944A1 - Facility and method for separating at least one ionic species from a solution comprising at least said ionic species and lithium - Google Patents

Abstract

The facility for separating a multivalent cationic species, from a solution comprising this multivalent cationic species and lithium, comprises a capturing device (3) which has an inlet (2) and an outlet (4). The capturing device (3) comprises, between the inlet (2) and the outlet (4), a microfibre product (21) with an affinity greater for multivalent cations than for monovalent cations. The facility comprises a circulation system (5) suitable for circulating the solution from the inlet (2) to the outlet (4) in contact with the microfibre product (21), the microfibre product (21) capturing said multivalent cationic species.

Description

 Description

 INSTALLATION AND METHOD FOR SEPARATING AT LEAST ONE ION SPECIES FROM

STARTING FROM A SOLUTION

 COMPRISING AT LEAST THE SAID ION SPECIES AND LITHIUM

[1] FIELD OF THE INVENTION

 [2] The present invention relates to an installation and a method for separating at least one ionic species from a solution comprising at least said ionic species and Lithium.

 [3] TECHNOLOGICAL BACKGROUND

 [4] More specifically, the invention relates to the recovery of Lithium.

 [5] Lithium is a widely used material, for example in the manufacture of batteries. There are several methods for obtaining Lithium. According to one example, the Lithium is recovered from salars, which are large areas comprising accumulations of salts from which aqueous saline solutions are extracted, from which the Lithium is extracted from the other cations contained in solution. These processes are essentially carried out by evaporation. However, the yield of Lithium is quite low, since a good part of it precipitates during the evaporation step aimed at reducing the magnesium content in the solution.

 [6] The document EP 0 785 170 takes place in a different context, namely that of the manufacture of zeolite products with Lithium used for the separation of nitrogen and air. The effluents from this manufacturing process, which are very concentrated in Lithium, are treated with powders.

 [7] Document US 2014 / 334.997 describes a process for the purification of a solution of lithium bicarbonate which is carried out on a solution stored under high pressure of carbon dioxide.

 [8] The document DE 100 08 940 describes a filter produced from polypropylene microfibers. The technical effect allowing the purification of the component to be removed is not described. It says that polypropylene is notoriously chemically inert. Consequently, the filtration effect is probably obtained by a simple mechanical effect of retention of the largest particles.

 [9] Document EP 2 522 631 describes a separation of the Lithium and the Magnesium contained in solution by means of a gel. The separation of the species is based on the size of the species facilitating their diffusion in the resin.

 [10] The present invention thus aims to improve the separation of the ionic species contained in solutions containing Lithium, in particular aqueous solutions containing Lithium such as, for example, brines of Lithium.

[11] SUMMARY OF THE INVENTION [12] Thus, the invention relates to an installation for the separation of at least one multivalent cationic species from a solution comprising at least the said multivalent cationic species and to Lithium, the said separation installation comprising:

 - at least one capture device comprising an input and an output, the capture device comprising, between the input and the output, an ion-exchange microfiber product having an affinity greater than multivalent cations than with monovalent cations,

 - a circulation system adapted to circulate the solution from the inlet to the outlet in contact with the microfiber product, said microfiber product capturing said multivalent cationic species.

 [13] Thanks to these provisions, the lithium can be separated from a divalent cation remaining in the solution at the inlet of the installation. The divalent cation is captured, while the Lithium remains in the solution. In addition, due to the ion exchange phenomenon, a cation is released, which can be Lithium, or another cation which is easier to separate from Lithium than the divalent cation.

 [14] According to different aspects, it is possible to provide one and / or the other of the provisions below.

 [15] According to one embodiment, the separation installation further comprises a recirculation device suitable for circulating part of the solution from the outlet to the inlet without passing through the microfiber product.

 [16] According to one embodiment, the capture device comprises a plurality of individual capture cells connected in series, the capture cells comprising said microfiber product, the individual capture cells connected in series comprising different saturation rates in said ionic species , and in particular in which the saturation rates are decreasing from upstream to downstream.

 [17] According to one embodiment, the microfiber product comprises Lithium, and the microfiber product captures said at least one cationic multivalent species by releasing Lithium.

 [18] According to one embodiment, the separation installation further comprises a regeneration system comprising a regeneration circulation device suitable for circulating a salting-out product in contact with the microfiber product, said microfiber product then releasing said multivalent cationic species .

 [19] According to one embodiment, the regeneration circulation device is adapted to circulate in contact with the microfiber product a refill product comprising lithium and / or sodium, said microfiber product then being charged with lithium and / or sodium. , respectively.

 [20] According to one embodiment, the separation installation comprises valves adapted to authorize or prohibit the circulation of solutions in different circuits, and pumps to generate circulation, and a controller programmed to control the valves.

[21] According to one embodiment, the separation installation contains an atmosphere, at the level of the microfiber product, the carbon dioxide content of which is less than 0.1% for a total pressure of less than 10 bars. [22] According to one embodiment, the separation installation comprises, in contact with the capture device, a solution of halide, in particular chloride, bromide and / or lodide, of lithium, lithium sulphate, lithium carbonate C0 ₃ ² , Lithium nitrate and / or Lithium hydroxide, the content of lithium bicarbonate of which is less than 1%, in particular less than 0.1% by mass.

[23] According to another aspect, the invention relates to an installation for producing Lithium Carbonate C0 ₃ ² comprising:

 Such a separation installation, providing a solution comprising lithium,

- A subsequent processing unit treating said solution comprising Lithium and producing Lithium Carbonate C0 ₃ ² .

 [24] According to another aspect, the invention relates to a cell for capturing at least one cationic multivalent species from a solution comprising at least said cationic multivalent species and Lithium intended to equip a device for capturing such an installation, said capture cell comprising:

 - an entrance,

 - output,

 - between entry and exit, a microfiber product with greater affinity for multivalent cations than for monovalent cations.

 [25] According to another aspect, the invention relates to a unit for capturing at least one cationic multivalent species from a solution comprising at least said cationic multivalent species and Lithium, said capture unit comprising a plurality such capture cells, a circulation system adapted to hydraulically connect said capture cells to each other, the circulation device comprising valves and pumps adapted to be controlled from a controller.

 [26] According to another aspect, the invention relates to a process for the separation of at least one multivalent cationic species from a solution comprising at least the said multivalent cationic species and Lithium, the said separation process comprising:

 - at least one capture device is provided comprising an inlet and an outlet, the capture device comprising, between the inlet and the outlet, a microfiber product having a higher affinity for multivalent cations than for monovalent cations,

 - With a circulation system, the solution is circulated from the inlet to the outlet in contact with the microfiber product, said microfiber product capturing said multivalent cationic species.

[27] According to one embodiment, a halide solution is provided, in particular lithium chloride, bromide and / or lodide, lithium sulphate, lithium carbonate C0 ₃ ² , lithium nitrate and / or lithium hydroxide, the content of which is Lithium bicarbonate is less than 1%, and in particular less than 0.1% by mass. [28] According to one embodiment, the atmosphere, at the level of the microfiber product, has a carbon dioxide content of less than 0.1% for a total pressure of less than 10 bars.

[29] According to another aspect, the invention relates to a process for the manufacture of Lithium Carbonate C0 ₃ ² comprising such a separation process, and in which the output solution is subjected to a subsequent treatment, by a unit of further processing.

 [30] According to another aspect, the invention relates to a process for regenerating a microfiber product used for the separation of at least one multivalent cationic species from a solution comprising at least said ionic species and Lithium , in which :

 - a regeneration circulation device circulates a salting-out product in contact with the ion-exchange microfiber product, said microfiber product then releasing said multivalent cationic species,

 - The regeneration circulation device circulates a refill product comprising lithium in contact with the microfiber product, said microfiber product then being charged with lithium.

 [31] According to another aspect, the invention relates to a method for treating a solution comprising a multivalent cationic species and Lithium, said method successively comprising cyclically such a method of capturing said multivalent cationic species and a such regeneration process.

 [32] BRIEF DESCRIPTION OF THE DRAWINGS

 [33] Embodiments of the invention will be described below with reference to the drawings, briefly described below:

 [34] [Fig. 1] is a schematic representation of a process for recovering Lithium from a salar.

 [35] [Fig. 2] is a schematic view of an example of implementation of a process step.

 [36] [Fig. 3] is a schematic view of an example of implementation of a process step.

 [37] [Fig. 4] is a schematic view of an example of implementation of a process step.

 [38] [Fig. 5] is a schematic view of an example of implementation of a process step.

 [39] [Fig. 6] is a schematic view of an example of implementation of a process step.

 [40] [Fig. 7] is a schematic view of an example of implementation of a process step during a step subsequent to the step shown in [Fig. 6].

 [41] [Fig. 8] is a partial schematic view of an installation according to one embodiment.

 [42] [Fig. 9] is a schematic view of an example of a cell used for implementing the method.

[43] [Fig. 10] is a schematic top plan view of a two-dimensional product used in the installation. [44] [Fig. 11] is a view in principle of the capture of a metal ion by a fiber.

 [45] [Fig. 12] is a schematic exploded view of part of a capture cell.

 [46] [Fig. 13] is a partial perspective view of an installation according to a second embodiment.

 [47] [Fig. 14] schematically shows in cross section another embodiment of a capture cell.

 [48] In the drawings, identical references denote identical or similar objects.

 [49] DEFINITIONS

 [50] For a chemical reaction, we call "affinity" the quantity A = Sn, m ,, where v, is the stoichiometric coefficient of the species i and m, the chemical potential of the species i.

 [51] An elementary object capable of implementing the capture described in this document is called a "capture cell".

 [52] The term "capture unit" is used to mean an autonomous object, comprising a capture cell, or a plurality of capture cells operatively connected together, as well as means for implementing the method (fluidic connections, controllers,. ..) so as to form a functional whole which can be integrated into an installation comprising one or more capture units.

 [53] The term "capture device" is used generically to designate any object capable of implementing the capture described in this document. It can thus designate both a "capture cell" and a "capture unit", or include one or more of these objects connected together in a functional manner.

 [54] DETAILED DESCRIPTION

 [55] First, the invention is presented in its application to a first embodiment, relating to the recovery of Lithium from a salar. FIG. 1 schematically represents the process for recovering Lithium from a salar. The input component of the process is a brine, or aqueous saline solution, from the salar. The aqueous saline solution is concentrated in salts. It notably includes significant concentrations of Chlorides, as well as Sodium, Potassium, Magnesium and Lithium cations. For example, the brine to be treated has the following concentrations:

 0.1 to 3 g / l of Lithium,

 0.5 to 50 g / l of Magnesium,

 20 to 200 g / l of Sodium,

5 to 50 g / l of Potassium. [56] During a first stage, the brine went from evaporation basin to evaporation basin. In each basin or group of basins, during evaporation, different salts precipitate. In particular, and successively, precipitate:

 Sodium Chloride (first pool),

 Sodium Chloride and Potassium Chloride (second and third pools),

Potassium Chloride and Magnesium Chloride (fourth pool),

 Magnesium Chloride, as well as the start of precipitation of Lithium Chloride (fifth basin).

 [57] At the end of these precipitation stages, the Lithium did not precipitate very much, so that its relative concentration in brine, compared to the other cations, increased. By way of example, at the end of these steps, the brine can have the following concentrations:

 10 to 70 g / l of Lithium, in particular 10 to 50 g / l of Lithium,

 10 to 250 g / l of Magnesium,

 1 to 5 g / l of Sodium,

 1 to 5 g / l of Potassium.

 [58] Thus, the Li / Mg concentration ratio in the solution increased significantly during these evaporation steps.

[59] At this stage, the Lithium is present in the solution in the form of a Halide (Chloride, Bromide or lodide) of Lithium, of a Lithium Sulfate, of a Carbonate of Lithium C0 ₃ ² , a Lithium Nitrate, and / or a Lithium Hydroxide. The lithium bicarbonate ions, not being stable in aqueous solution, may be present in trace amounts, in any event in a concentration of less than 1%, or even less than 0.1% by mass.

 [60] The process which is the subject of the present invention finds its application, according to one embodiment, in the separation of the Lithium resulting from this last precipitation step. It is a question of purifying the Lithium of the important concentration of Magnesium remaining in the solution. The present process can thus be designated by the terms "purification" or "refining". This step could alternatively be done by precipitation, according to the prior publicly known methods, but the precipitation dynamics of the two species overlap, and a significant amount of Lithium is lost during the precipitation of Magnesium.

[61] Figure 2 schematically shows a separation installation 1 according to a first embodiment. The separation installation 1 comprises an inlet 2, a capture device 3 downstream of the inlet, and an outlet 4 downstream of the capture device 3. A circulation system 5 circulates the fluid from the inlet 2, through the capture device 3, towards the outlet 4, at a suitable rate. The treatment can be carried out in atmospheric air. The treatment can be carried out at atmospheric pressure. Alternatively, the treatment can be carried out under a controlled atmosphere. In the present case, the controlled atmosphere does not need to be rich in carbon dioxide. A carbon dioxide content of less than 0.1% is expected for a total pressure of less than 10 bars. The brine to be treated can be diluted with treated brine (treatment described below) from the subsequent treatment unit 28. Schematically, the circulation system 5 is shown in FIG. 2 between the capture device 3 and the outlet 4, however it could be carried out in any suitable manner, comprising one or more pumps distributed in various locations necessary for the circulation of fluid.

[62] The capture device 3 comprises a microfiber product suitable for the separation of some of the ion species from the solution present at the input. The microfiber product is in the form of a volume product made from one or more fibers arranged to form a compact solid assembly. A product is considered "volume" if these three dimensions have dimensions of similar order of magnitude. The volume product can be made from a two-dimensional product 22, folded over itself several times, or of which several layers are assembled together, as shown for example in FIG. 10. The two-dimensional product, for its part, is produced from fibers. The two-dimensional product comprises for example a nonwoven, a fabric or a felt. A fiber is a flexible product whose length is much greater than the other two dimensions. In the example presented, it has a circular section. However, other embodiments are possible. In the present case, the transverse dimension (diameter) of the fiber is of the order of 1 micrometer to 200 micrometers, in particular between 10 and 40 micrometers. The fibers can be used raw for making the two-dimensional product, or treated to make non-woven felt, thread, or woven, then used for making the two-dimensional product. The fibers have the advantage that, in a given volume, they have a large surface area while being easy to keep in a container, in particular by comparison with traditionally used powders comprising balls with a diameter of the order of 0.1 mm at 2 mm. According to an exemplary embodiment, the use of microfibers makes it possible to obtain a specific surface at least greater than 50 square meters per liter, or even at least 100 m ² / l, where the specific surface designates the area of the free surface fibers contained in a volume of 1 liter.

[63] Fibers are ion exchange fibers. These fibers contain, in particular consist of, a material having a strong affinity for multivalent cations. In particular, according to this embodiment, this material has a strong affinity for the Mg ²⁺ ion. According to one embodiment, this material is loaded with Lithium. Lithium is present as an ion used for ion exchange. The fiber is insoluble in an aqueous solution. The term "insoluble" means that the morphology of the fibers does not undergo detectable changes using an electron microscope after at least 24 hours of immersion in an essentially aqueous solution. In addition, the fibers are porous to water. This feature allows water to access chemical reaction sites inside the fibers.

[64] According to a first example, the fiber is a polymer fiber carrying carboxylic acid functional groups. These acid groups can be de-protonated in basic medium and transform into a carboxylate ion accompanied by a cationic counterion. These carboxylate ions prefer to be accompanied by multivalent cations. This “accompanying” cation can be released by acidification, in which case the carboxylate ion becomes carboxylic acid again.

 [65] According to a second example, the fiber is a polymer fiber carrying iminodiacetic acid functional groups. These groups play the role of chelating forceps. They have a very strong tendency to complex multivalent cations. This “accompanying” cation can be released by strong acidification.

 [66] In a particular case, it is possible, for example, to use fibers marketed, on the priority date, by the company AJELIS, under the names METALICAPT®-MFB or METALICAPT®-MFD.

 [67] According to an independent aspect, an invention relates to a fiber, as presented above, loaded with Lithium.

 [68] As shown schematically in Figure 11, the fibers 24 have a large exchange surface, based on the total volume of microfiber product. This allows a large number of 25 cations to be fixed there. This characteristic makes it possible to envisage an efficiency of the ion exchange process compatible with the application of lithium / magnesium separation, greater than that of traditional resin-based technologies. ion exchanges. Furthermore, the fibrous nature of the material, despite its large exchange surface, leaves large passage areas, and consequently generates a low pressure drop (low flow resistance, ie low energy consumption).

 [69] The microfiber product, before processing, is dry, and can be stored and transported dry, which is not the case for “conventional” ion exchange resins which must be transported and stored at a rate high humidity subject to losing their characteristics.

 [70] Thus, in one production mode, the circulation system 5 circulates the fluid in contact with the microfiber product when it passes from the inlet to the outlet. The microfiber product has more affinity for magnesium cations (divalent) than for lithium cations (monovalent). In contact with the microfiber product, the Magnesium in the solution is captured by the material on the sites previously loaded with Lithium, which is thus released. The Lithium initially present in the solution, on the other hand, is not captured by the microfiber product, and gains output 4. This is followed by a selective capture of the Magnesium.

 [71] To increase the efficiency of the magnesium capture, a solution comprising an optimal concentration of magnesium can be introduced into the capture device 3 (depending on the capture capacity, the residence time, and / or the reaction kinetics). The optimum concentration may depend on the configuration of the capture device 3, but may typically be in the range 100 - 10,000 mg / l, in particular 500 - 5,000 mg / l or 1,000 - 10,000 mg / l.

[72] This concentration can for example be obtained by diluting the solution upstream of the inlet. One can for example dilute the solution with water. As a variant, and as shown in FIG. 3, the solution can be diluted with the solution leaving the capture device 3. Thus, by means of a recirculation device 6, part of the solution is derived at the outlet of the capture device. capture 3, depleted in Magnesium, towards entry 2, where it dilutes the initial solution, without major modification of the concentration in other salts and in particular in Lithium.

 [73] The separation installation also includes a regeneration system 7, shown in Figure 4 in the context of the embodiment of Figure 2 (this system also being compatible with the embodiment of Figure 3). As shown in FIG. 4, the circulation system 5 also comprises an inlet valve 8, equipping the inlet 2, and controllable to alternately allow or prohibit the entry of the solution into the capture device 3. The system of circulation 5 also includes an outlet valve 9, fitted to outlet 4, and controllable to alternatively authorize or prohibit the outlet of the solution from the capture device 3 towards the outlet.

[74] The regeneration system 7 comprises a source of release product 10, suitable for discharging the microfiber product in cations. The salting-out product comprises for example an acid, such as a hydrochloric acid solution, of pH at most equal to 4. The regeneration system 7 comprises a source of recharging product 1 1, suitable for recharging the product in cations microfiber. The refill product comprises for example a base, such as for example a solution of lithium hydroxide or lithium carbonate C0 ₃ ² , of pH at least equal to 9. The regeneration system 7 comprises a source of rinsing product 23 , suitable for rinsing the microfiber product and removing the components likely to have a negative influence on the rest of the process. The rinse aid comprises, for example, water. The regeneration system 7 comprises a regeneration circulation device 12 adapted to circulate the fluids through the capture device 3. The regeneration circulation device 12 can comprise pumps 13, and valves 14 arranged on the different channels and adapted to alternatively authorize or prohibit the circulation of fluid in this channel.

 [75] A controller 15 controls the valves 8, 9, 14 and the pumps according to a preprogrammed procedure, to ensure regeneration. In the example of embodiment presented, a single microfiber product has been represented. However, the microfiber product can be installed in several columns independent of each other. In this case, according to the embodiments, a valve can be installed for a single column or for a group of columns (typically a group of columns can comprise from two to several hundred columns).

 [76] During a release step, the inlet 8 and outlet 9 valves are closed. The release fluid is circulated from the source of release product 10 through the capture device 3. During this step, the magnesium captured by the microfiber product is released from it, and circulated to the outside 16 .

[77] During a refill step, the refill product is circulated from the source of refill product 11 through the capture device 3. During this step, the microfiber product is recharged with Lithium. In the case where the refill product is Lithium Hydroxide, it interacts with the microfiber product to charge it with Lithium. Lithium hydroxide is circulated outside 16. [78] A rinsing step can be carried out, using the rinsing product 23 before and after each of these steps and the production steps (rinsing of the residual solution, of the residual acid, of the residual base) .

 [79] A purge system can be provided, for example under compressed air, after each step, to remove the residual liquid.

 [80] The ion exchange mechanism, in the case of a fiber containing carboxylic acid groups, and an effluent composed of lithium and magnesium chloride, can be summarized as follows:

 [81] Separation step:

[82] (2 COCT, 2 Li ⁺ ) _fibers + (Mg ²⁺ , Li ⁺ , CI) _circulating -> (2 COCT, Mg ²⁺ ) _fibers + (Li ⁺ , CI) _circulating

 [83] Relarqaqe step:

[84] (2 COCT, Mg ²⁺⁾ _flbres + (H ^+, Cl) _flowing -> (2 COOH) _flbres + (Mg ²⁺ H ^+, Cl) _flowing

 [85] Recharge step:

[86] (2 COOH) _fibers + (Li ⁺ , OH) _{circU | ant} -> (2 COOH, 2 Li ⁺ ) _fibers + (U ⁺ , OH) _{circU | ant} + H ₂ 0

 [87] The process which has just been described makes it possible to process the incoming solution cyclically.

 [88] A capture cell capable of implementing the above method is shown in FIG. 9. In FIG. 9, the capture cell 17 is hydraulically connected to the inlet 2 at a first side of the detection cell. capture 17. It is hydraulically connected to the outlet 4 on a second side of the capture cell 17, opposite the first side. The capture cell 17 is hydraulically connected, on the second side, to refill product tanks 29, 29 ′, a release product tank 30 and to a rinse product tank 31. It is hydraulically connected, on the first side , to return circuits of refill product 32, 32 ′, a return circuit of release product 33, and to a return circuit of rinse product 34. Thus, the recharge, release and rinse products circulate, in the capture 17, in the opposite direction to the solution to be treated.

[89] In the example above, the separation step must be stopped during the regeneration of the capture device 3. As a variant, it can be provided, as shown in FIG. 5, that the capture device 3 comprises several capture units 16 each designed like the capture device 3 described above, and which can be connected alternately with the main circuit and with the regeneration circuit. Thus, it is possible to use a capture unit 16 for capturing the Magnesium from the incoming solution and, in parallel, to regenerate another capture unit 16. Then, after a certain time, the roles are exchanged . The process is carried out repeatedly. In this way, the process is made continuous, and makes it possible to receive as input a continuous flow of solution to be treated and to produce a final solution also in continuous flow. The system is controlled by the controller 15. The total number of units, and the sequencing of implementation, will depend on the time required for the implementation of each stage of production, rinsing, salting out, recharging, purging, controlling the valves, or any other necessary step and the expected production volume / flow.

 [90] Figure 8 describes an alternative embodiment with six cells. Thus, compared with FIG. 9, the capture cells 17 comprise additional lines, making it possible to hydraulically connect alternately the input side of a capture cell 17 either directly with the input 2, or with an upstream capture cell. Compared to FIG. 9, the capture cells 17 also include additional lines, making it possible to hydraulically alternately connect the outlet side of a capture cell 17 either directly with the outlet 4, or with a downstream capture cell.

 [91] Over time, the microfiber product becomes loaded with Magnesium. With an increasing concentration of captured magnesium, the absorption capacity of magnesium by the microfiber product decreases. Thus, one may be tempted to put the microfiber product in regeneration mode earlier to eliminate a maximum concentration of Magnesium. However, in this case, the capture phases and the regeneration phases are quickly alternated, which affects the overall efficiency of the system. The controller 15 is programmed to operate at an optimal operating point for each site and adjustable.

[92] An alternative embodiment is shown in Figure 6. Figure 6 shows a capture unit 16 in the capture phase. The capture unit 16 comprises a plurality of capture cells 17-i, 17 ₂ , 17 ₃ , 17 ₄ . The capture cells can be designated by the generic reference 17. For the example, four capture cells are described, but the number could be different, typically between two and ten, or even more. Each capture cell is designed like the capture device 3 described above, except that the capture cells are connected together in series. According to a particular case, along the path of the solution from inlet 2 to outlet 4, the capture cells have a decreasing saturation in Magnesium. That is to say that the capture cell 17-i connected to the input is more saturated with magnesium than the next, and so on, until the output.

[93] In this embodiment, when the capture cell 17 ₄ is saturated with magnesium beyond a predetermined saturation threshold, it is no longer used for the implementation of the capture step 16. Input 2 is then connected to the remaining capture cell most saturated with Magnesium, namely, a priori, capture cell 17 ₂ . If necessary, simultaneously or subsequently, a capture cell 17 ₅ resulting from the regeneration step, slightly saturated with magnesium, is connected downstream of the capture cell 17 ₄ upstream of the outlet 4, as visible in the figure. 7. The capture cell 17 -i undergoes the regeneration process. The capture step is then implemented with the capture cells 17 ₂ , 17 ₃ , 17 ₄ , 17 ₅ . All of the above steps can be obtained by suitable control of the valves by the controller 15, without any displacement of the capture cells or of the pipes. This implementation increases the overall productivity of the process.

[94] FIG. 9 schematically represents an example of a capture cell 17 according to an embodiment. The capture cell 17 comprises a rigid enclosure 18. The microfiber product 21 is placed inside the enclosure 18. According to an exemplary embodiment, the capture cell 17 includes a mechanical holding system (not shown) holding the microfiber product 21 in place despite the fluid flow through the capture cell 17. As shown in Figure 9, there is a flow of the solution to be treated in a direction to through the capture cell 17, and a flow of the other fluids in the opposite direction. The capture cell 17 is hydraulically connected, via dedicated valves, to the inlet 2 and to the outlet 4 in solution to be treated, to two refill product tanks 29, 29 ′, to a product tank release 30, and to a rinse aid reservoir 31. It is also hydraulically connected to returns of refill product 32, 32 ′, release product 33, and rinse aid 34 downstream of the capture cell 17 .

 [95] According to an exemplary embodiment, as shown in FIG. 12, two-dimensional products 22 are stacked with the interposition of holding devices 35 which mechanically hold the two-dimensional products in place while allowing a fluid flow of the solutions through the cell. The holding devices 35 comprise for example flexible spacers perforated in any suitable material. The assembly is shaped, for example by cutting, folding, and winding around a central core 36 and fixed in the enclosure 18. Other embodiments are possible.

 [96] Figure 8 thus represents the implementation of six cells, each as described above in relation to Figure 9, so as to implement the different stages of the phases described above. Among these, the solution inlet valve of certain cells is connected to inlet 2 via the outlet of an upstream cell. Among these, the solution outlet valve of certain cells is connected to outlet 4 via the inlet of a downstream cell.

 [97] Figure 14 schematically shows another embodiment of a capture cell 17, operating radially. The capture cell 17 has a cylindrical architecture, of section of revolution or other, the external radial surface 37 of which constitutes an inlet for the solution (see arrows in FIG. 14). The microfiber product 21 is disposed between the outer radial surface 37 and an outlet. The outlet is for example produced by an axial pipe 38, surrounded by the microfiber product 21. The circulation device circulates the solution, in production mode, from the inlet to the outlet. In this embodiment, the capture cell offers a large attack surface for the solution. As in the first embodiment, the regeneration step would be implemented by circulating fluids in the opposite direction through the capture cell 17. The outlet can be connected, downstream, to another cell.

 [98] The capture cells 17 described above can, depending on the embodiments, be surrounded by a filtering element with mechanical action, of the tissue or micro-perforated film type, for the retention of any solid particles contained in the solution, for example resulting from precipitation during previous stages of the process.

[99] Figure 13 shows a second embodiment of an installation. According to this exemplary embodiment, the installation comprises several stations each dedicated to a particular task, and separated from one another in space. In this example, each station includes a pool in which a solution is contained. A capture unit 16 is transported by a transport device 26 from station to station, for the needs of the method. The capture unit is immersed in the solution at the station. It is thus possible to provide a limited number of valves for controlling the process. Indeed, for example, it suffices to equip each station with a single inlet valve and a single outlet valve, the capture unit 16 comprising any number of capture cells fixedly connected to each other. , in series and / or in parallel. In addition, depending on the concentration of Magnesium in the solution present in the basin, the chronology of movements of the capture units 16 may change.

[100] According to the simplified example shown, the installation comprises a treatment station 27-i, a rinsing station 27 ₂ , a release station 27 ₃ , and a recharging station 27 ₄ , and the unit 16 is moved from station to station according to the needs of the process. If the method implements the placing in series of several cells during the processing step, as explained above in relation to FIGS. 6 and 7, then the installation can include several stations each corresponding, at a given time , at a different level of Magnesium concentration. Over time, at the same station, the concentration of Magnesium in the solution contained in the basin will drop. At a certain stage, a basin will be emptied, then filled with a solution very loaded with Magnesium. The sequence of movement of the units 16 from basin to basin will then be modified, to follow the rule that a unit must be plunged successively into basins having an increasing concentration of Magnesium over time.

 [101] As a variant, the material constituting the fibers is loaded with sodium. The Sodium is present as the ion used for the ion exchange.

 [102] In this case, the ion exchange mechanism, in the case of a fiber with carboxylic acid groups, can be summarized as follows:

 [103] Separation step:

[104] (2 COCT, 2 Na ⁺⁾ _flbres + (Mg ^2+, Li ^+, Na +, Cl) _flowing -> (2 COCT, Mg ²⁺⁾ _flbres + (Li ^+, Na ^+, Cl) _flowing

[105] Relarqaqe step:

[106] (2 COCT, Mg ²⁺ ) _flbre + (H ⁺ , Cr) _circulating -> (2 COOH) _flbre + (Mg ²⁺ 'H ⁺ , Cr) _circulating

 [107] Recharge step:

[108] (2 COOH) _flbre + (Na ⁺ , OH) _circulating -> (2 COCT, 2 Na ⁺ ) _flbre + (Na ⁺ , OH) _circulating + H ₂ 0

[109] This variant can in particular be used if the presence of Sodium in the solution resulting from the process is not a hindrance for the subsequent stages of the process for manufacturing Lithium carbonate C0 ₃ ² . It can in particular be used if the entry solution already comprises a significant amount of Sodium.

[1 10] As shown in FIG. 1, the solution resulting from the process described above is subjected to a subsequent treatment, by a subsequent treatment unit 28, leading to the production of lithium carbonate Li ₂ C0 ₃ . This treatment can for example include an addition of Calcium oxide to precipitate magnesia, and include different successive stages of sedimentation, filtration and precipitation, as well as a final drying and cooling step. As discussed above, the recovered liquids can be reintegrated at the inlet of the separation installation 1. The separation process can be implemented on site after the evaporation process in the evaporation tanks. At the end, the solution rich in Lithium is taken to a refinery for the implementation of the subsequent stages. Alternatively, the separation process is carried out near the refinery. The input solution is led from the evaporation tanks to the refinery, where it is treated by implementing the present process first.

 [111] Examples

 [112] A test was implemented in the laboratory with a capture unit comprising six capture cells connected in series as described above in relation to FIG. 6, the capture unit implementing the principle of recirculation explained in relation to FIG. 3. Each capture cell, containing 8 ml, contains 1.5 g of microfiber product.

 [113] The entry solution is a solution coming from an evaporation basin of a South American salar, and having the following composition:

 Li: 1.69%

 Mg: 5.87%

 Li / Mg ratio: 0.29

[114] The microfiber product comprises METALICAPT ^(R) -MFD fibers obtained in bulk from the company AJELIS, placed in an enclosure forming the cell. The concentration of Magnesium, in the initial solution, as in samples of the output solution, is measured using a multi-parameter spectrophotometer C200 Hanna Instrument.

 [115] For an input sample having a magnesium concentration close to 100,000 mg / l, and a dilution by 40 by recirculation, the resulting magnesium content in the output solution, before saturation, is substantially constant and less than 50 mg / l.

[116] The treatment method which has just been described in an Mg / Li separation application in brine from a salar can alternatively be implemented for any brine from which it is desired to extract a divalent ion such as Magnesium ( Mg ²⁺ ), Calcium (Ca ²⁺ ), Strontium (Sr ²⁺ ), Barium (Ba ²⁺ ), etc.

 [117] The process which has just been described can also be implemented for the separation of barium or strontium.

[118] Typically, in an application example, the flow speed through the installation is of the order of 1 to 100 m ³ / m ² / h, where the cubic meters denote the volume of solution passing to through the installation, the square meters the equivalent cross section of the capture device orthogonally to the direction of flow, and the time is expressed in hours. References :

 Separation installation 1 capture unit 16 refill product tanks 29, 29 ’

Input 2 capture cell 17

 capture device product tank 3 enclosure 18

 release 30

outlet 4 microfiber product 21

 circulation system product tank 5 two-dimensional product 22

 rinse 31

re-circulation device 6 source of rinse aid

 23 product return

regeneration system 7 refill 32, 32 ’

 fiber 24

inlet valve 8 cation product return 25 release 33

outlet valve 9

 transport device 26 return of rinse aid release product 10

 34

 27-i treatment station

refill product 1 1

holding devices 35 rinsing station 27 ₂

circulation device

central core 36 regeneration 12 release station 27 ₃

external radial surface 37 pumps 13 charging station 27 ₄

 pipeline 38 axial valves 14 further processing unit

 28

controller 15

Claims

 [Claim 1] Installation for separating at least one multivalent cationic species from a solution comprising at least said multivalent cationic species and Lithium,

said separation installation (1) comprising:

 - at least one capture device (3) comprising an inlet (2) and an outlet (4), the capture device (3) comprising, between the inlet (2) and the outlet (4), a microfiber product ( 21) ion exchanger having a higher affinity to multivalent cations than to monovalent cations,

 - a circulation system (5) adapted to circulate the solution from the inlet (2) to the outlet (4) in contact with the microfiber product (21), said microfiber product (21) capturing said multivalent cationic species.

[Claim 2] Separation installation according to claim 1, further comprising a recirculation device (6) adapted to circulate part of the solution from the outlet (4) to the inlet (2) without passing through the microfiber product (21).

[Claim 3] Separation installation according to claim 1 or 2, wherein the capture device (3) comprises a plurality of individual capture cells (17) connected in series, the capture cells comprising said microfiber product, the cells of individual capture (17) connected in series comprising different saturation rates in said ionic hope, and in particular in which the saturation rates are decreasing from upstream to downstream.

[Claim 4] Separation installation according to any one of claims 1 to 3, in which the microfiber product (21) comprises Lithium, and in which the microfiber product (21) captures said at least one multivalent cationic species by releasing Lithium.

[Claim 5] Separation installation according to any one of claims 1 to 4, further comprising a regeneration system (7) comprising a regeneration circulation device (12) adapted to circulate a salting out product (10) in contact with the microfiber product (21), said microfiber product (21) then releasing said multivalent cationic species.

[Claim 6] Separation installation according to claim 5, wherein the regeneration circulation device (12) is adapted to circulate in contact with the microfiber product (21) a refill product (1 1) comprising Lithium and / or Sodium, said microfiber product (21) then being charged with Lithium and / or Sodium, respectively.

[Claim 7] Separation installation according to any one of claims 1 to 6, comprising valves (14) adapted to authorize or prohibit the circulation of the solution in different circuits, pumps (13) to generate a circulation, and a controller (15) programmed to control the valves (14).

[Claim 8] Separation installation according to any one of claims 1 to 7, containing an atmosphere, at the level of the microfiber product, the carbon dioxide content of which is less than 0.1% for a total pressure of less than 10 bars .

[Claim 9] Separation installation according to any one of claims 1 to 8, comprising, in contact with the capture device, a solution of halide, in particular chloride, bromide and / or lodide, of lithium, lithium sulphate, carbonate of Lithium C0 ₃ ² , Lithium Nitrate and / or Lithium Hydroxide, the content of lithium bicarbonate of which is less than 1%, in particular less than 0.1% by mass.

[Claim 10] Production plant for Lithium Carbonate C0 ₃ ² comprising:

 A separation installation according to one of claims 1 to 9, providing a solution comprising lithium,

A subsequent processing unit (28) treating said solution comprising Lithium and producing Lithium Carbonate C0 ₃ ² .

[Claim 1 1] Cell for capturing at least one multivalent cationic species from a solution comprising at least said multivalent cationic species and Lithium intended to equip a capture device with an installation according to any one of the claims 1 to 9, said capture cell (17) comprising:

 - an entrance,

 - output,

 - between entry and exit, a microfiber product (21) having a greater affinity for multivalent cations than for monovalent cations.

[Claim 12] Unit for capturing at least one multivalent cationic species from a solution comprising at least said multivalent cationic species and Lithium, said capture unit (16) comprising a plurality of capture cells (17) according to claim 10, a circulation system (5) adapted for hydraulically connecting said capture cells (17) to each other, the circulation device (5) comprising valves (14) and pumps (13) adapted to be controlled from a controller (15).

[Claim 13] Method for separating at least one multivalent cationic species from a solution comprising at least said multivalent cationic species and Lithium,

said separation process comprising:

 - at least one capture device (3) is provided comprising an inlet (2) and an outlet (4), the capture device (3) comprising, between the inlet (2) and the outlet (4), a product microfiber (21) ion exchanger having a higher affinity for multivalent cations than for monovalent cations,

 - With a circulation system (5), the solution is circulated from the inlet (2) to the outlet (4) in contact with the microfiber product (21), said microfiber product (21) capturing said multivalent cationic species.

[Claim 14] The method of claim 13, wherein a solution of

Halide, in particular Chloride, Bromide and / or Lithium lodide, Lithium Sulfate, Lithium carbonate C0 ₃ ² , Lithium Nitrate and / or Lithium Hydroxide, the content of lithium bicarbonate of which is less than 1%, and in particular less at 0.1% by mass.

[Claim 15] Method according to claim 13 or 14, wherein the atmosphere, at the level of the microfiber product, has a carbon dioxide content of less than 0.1% for a total pressure of less than 10 bars.

[Claim 16] Process for the manufacture of Lithium Carbonate C0 ₃ ² comprising a separation process according to one of claims 13 to 15, and in which the output solution is subjected to a subsequent treatment, by a subsequent treatment unit ( 28).

[Claim 17] Method for regenerating a microfiber product (21) used for the separation of at least one multivalent cationic species from a solution comprising at least said ionic species and Lithium, in which:

 - a regeneration circulation device (12) circulates a salting-out product (10) in contact with the ion exchange microfiber product (21), said microfiber product (21) then releasing said multivalent cationic species,

 - The regeneration circulation device (12) circulates a refill product (1 1) comprising lithium in contact with the microfiber product (21), said microfiber product (21) then being charged with lithium.

[Claim 18] Method for treating a solution comprising a multivalent cationic species and Lithium, said method successively comprising in a cyclic manner the method for capturing said multivalent cationic species according to one of claims 13 to 15 and the regeneration method of claim 17.