Lithium adsorption extraction process with alternating cascade bed elution

Abstract

The present invention relates to a lithium adsorption extraction process employing a plurality of consecutive adsorption / desorption steps and using a plurality of extraction columns (C1-C4) arranged / operated in series for an adsorption phase (a) and a plurality of extraction columns (C1-C4) arranged / operated in series for a desorption phase (b), the position / operation of the extraction columns (C1-C4) being shifted by an equivalent / value of one extraction column (C1-C4) from step i to step i+1. Figure 1 to be published

Description

Title of the invention: Lithium adsorption extraction process with cascade alternating bed elution technical field

[0001] The present invention relates to the field of lithium adsorption extraction. Previous technique

[0002] Demand for lithium has increased sharply in recent years, largely due to the rise of electric mobility. To meet this demand, improving existing lithium extraction processes is essential. Lithium can be extracted from rocks or from brines. In the case of brines, traditional processes are based on open-air evaporation, a slow and low-yield process. Adsorption processes have recently been developed and offer promising prospects.

[0003] Patent FR3053264B1 describes the preparation of a lithium selective adsorbent of formula (LiCl)x.2Al(OH)3,nH2O with n being between 0.01 and 10, x being between 0.4 and 1, for the extraction of lithium from saline solutions.

[0004] This type of adsorbent can be implemented in cyclic adsorption and desorption processes in which the brine passes through an extraction column in which the lithium is captured, the latter then being fed with an eluent to desorb the desired lithium.

[0005] Several types of adsorption and desorption cycles are possible, and the choice of configuration and associated settings significantly impacts the process performance. Thus, lithium adsorption extraction can be improved. Summary of the invention

[0006] In the context described above, a first object of the present invention is to overcome the problems of the prior art and to provide a lithium adsorption extraction process that increases the lithium yield and the lithium concentration in the extract.

[0007] According to a first aspect, the aforementioned objects, as well as other advantages, are obtained by a lithium adsorption extraction process, using a plurality (n) of extraction columns, each comprising a bed of adsorbent solid and arranged in series, of which a plurality of extraction columns are positioned (operated) in the adsorption phase and a plurality of extraction columns are positioned in the desorption phase, comprising the following steps: a step i comprising: - an adsorption substage in which extraction columns, referred to as "adsorption phase" columns, are fed with at least one charge comprising lithium, and at least one raffinate is withdrawn from said adsorption phase extraction columns, a first adsorption phase extraction column being disposed (operated) upstream of a last adsorption phase extraction column; and - simultaneously or consecutively to the adsorption substep, a desorption substep in which extraction columns, referred to as "in the desorption phase," are fed with at least one desorbent, and at least one extract is withdrawn from said extraction columns in the desorption phase, a first extraction column of the extraction columns in the desorption phase being arranged (operated) upstream of a last extraction column in the desorption phase, a step i+1 consecutive to step i (step i+1 being carried out after a predetermined duration of time, and / or when the first extraction column of the extraction columns in the adsorption phase of step i has a lithium content greater than or equal to a first predetermined lithium content,and / or when the first extraction column in the desorption phase of step i has a lithium element content less than or equal to a second predetermined lithium element content), step i+1 repeating the adsorption and desorption substeps of step i and in which the position (the order of operation) of the (n) extraction columns is shifted by a value of one extraction column such that, that : - the first extraction column of the extraction columns in the adsorption phase of step i is positioned (operated) as the last extraction column of the extraction columns in the desorption phase of step i+1; - a second extraction column of the extraction columns in the adsorption phase of step i is positioned (operated) as the first extraction column of the extraction columns in the adsorption phase of step i+1; - the first extraction column of the extraction columns in the desorption phase of step i is positioned (operated) as the last extraction column of the extraction columns in the adsorption phase of step i+1; and - a second extraction column of the extraction columns in the desorption phase of step i is positioned (operated) as the first extraction column of the extraction columns in the desorption phase of step i+1.

[0008] According to one or more embodiments, the process comprises at least the following steps: a first step including: - an adsorption substage in which the plurality of extraction columns, referred to as "in the adsorption phase," are fed with at least one charge comprising lithium, and at least one refiner is withdrawn from said extraction columns in the adsorption phase, a first extraction column in the adsorption phase being arranged upstream of a last extraction column in the adsorption phase in the direction of the flow of the fluids passing through said extraction columns in the adsorption phase; and - simultaneously or consecutively to the adsorption substep, a desorption substep in which the plurality of extraction columns, referred to as "in desorption phase," are fed with at least one desorbent, and at least one extract is withdrawn from said extraction columns in desorption phase, a first extraction column in desorption phase being upstream of a last extraction column in desorption phase according to the direction of the flow of the fluids passing through said extraction columns in desorption phase, a second step following the first step (the second step being carried out after the predetermined time period, and / or when the first extraction column in the adsorption phase of the first step has a lithium content greater than or equal to the first predetermined lithium content, and / or when the first extraction column in the desorption phase of the first step has a lithium content less than or equal to the second predetermined lithium content), the second step repeating the adsorption and desorption substeps of the first step and in which: - the first extraction column in the adsorption phase of the first step is positioned as the last extraction column in the desorption phase of the second step; - the second extraction column in the adsorption phase of the first step is positioned as the first extraction column in the adsorption phase of the second step; - the first extraction column in the desorption phase of the first step is positioned as the last extraction column in the adsorption phase of the second step; and - the second extraction column in the desorption phase of the first step is positioned as the first extraction column in the desorption phase of the second step.

[0009] According to one or more embodiments, the process comprises a third step following the second step and repeating the adsorption and desorption substeps of the second step (the third step being carried out after the predetermined time period, and / or when the first extraction column in phase the adsorption column of the second stage has a lithium content greater than or equal to the first predetermined lithium content, and / or when the first extraction column in the desorption phase of the second stage has a lithium content less than or equal to the second predetermined lithium content), in which: - the first extraction column in the adsorption phase of the second stage is positioned as the last extraction column in the desorption phase of the third stage; - the second extraction column in the adsorption phase of the second stage is positioned as the first extraction column in the adsorption phase of the third stage; - the first extraction column in the desorption phase of the second step is positioned as the last extraction column in the adsorption phase of the third step; and - the second extraction column in the desorption phase of the second step is positioned as the first extraction column in the desorption phase of the third step.

[0010] According to one or more embodiments, the process comprises a fourth step following the third step and repeating the adsorption and desorption substeps of the third step (the fourth step being carried out after the predetermined time period, and / or when the first extraction column in the adsorption phase of the third step has a lithium content greater than or equal to the first predetermined lithium content, and / or when the first extraction column in the desorption phase of the third step has a lithium content less than or equal to the second predetermined lithium content), wherein: - the first extraction column in the adsorption phase of the third stage is positioned as the last extraction column in the desorption phase of the fourth stage; - the second extraction column in the adsorption phase of the third stage is positioned as the first extraction column in the adsorption phase of the fourth stage; - the first extraction column in the desorption phase of the third step is positioned as the last extraction column in the adsorption phase of the fourth step; and - the second extraction column in the desorption phase of the third step is positioned as the first extraction column in the desorption phase of the fourth step.

[0011] According to one or more embodiments, the first step is consecutive to the fourth step and repeats the adsorption and desorption substeps of the fourth step (the first step being carried out after the predetermined time period, and / or when the first extraction column in the adsorption phase of the fourth step has a lithium content greater than or equal to the first predetermined lithium content, and / or when the first extraction column in the desorption phase of the fourth step has a lithium content less than or equal to the second predetermined lithium content), wherein: - the first extraction column in the adsorption phase of the fourth step is positioned as the last extraction column in the desorption phase of the first step; - the second extraction column in the adsorption phase of the fourth stage is positioned as the first extraction column in the adsorption phase of the first stage; - the first extraction column in the desorption phase of the fourth step is positioned as the last extraction column in the adsorption phase of the first step; and - the second extraction column in the desorption phase of the fourth step is positioned as the first extraction column in the desorption phase of the first step.

[0012] According to one or more embodiments, the process comprises an n-step cycle, in which at the end of step n, the extraction columns of step n are repositioned to their original positions of step 1.

[0013] According to one or more embodiments, n is greater than or equal to 4, preferably n is between 4 and 8, preferably n is between 4 and 6, preferably n is equal to 4.

[0014] According to one or more embodiments, n is equal to 4, two extraction columns being positioned in the adsorption phase and two extraction columns being positioned in the adsorption phase.

[0015] According to one or more embodiments, at least one adsorption substep and / or at least one desorption substep comprises at least two periods, each period being differentiated from another period by the lithium content of the feed and / or desorbent fed and / or the raffinate and / or the extract withdrawn, the position (the order of operation) of the extraction columns during said adsorption substep and / or desorption substep being unchanged.

[0016] According to one or more embodiments, at least one adsorption substep comprises at least two periods, in which a first raffinate withdrawn during a first period is removed from the process or is at least partially recycled as a desorbent, and a second raffinate withdrawn during a second period is removed from the process as a lithium-depleted outflow stream.

[0017] According to one or more embodiments, at least one desorption substep comprises at least two periods, in which a first extract withdrawn during a first period is removed from the process or is optionally at least partially recycled as a feed, and in which a second extract withdrawn during a second period is removed from the process as a lithium-enriched output stream.

[0018] According to one or more embodiments, the charge comprises, and preferably consists of, a solution containing lithium and saturated with salts.

[0019] According to one or more embodiments, the charge comprises at least 0.05 g / L of lithium element, preferably in the form of LiCl.

[0020] According to one or more embodiments, the desorbent is chosen from the group consisting of water, lithia water, brine, preferably water.

[0021] According to one or more embodiments, the desorbent comprises between 0 g / L and 1 g / L of lithium element, preferably in the form of LiCl.

[0022] According to one or more embodiments, the adsorbent solid comprises at least one lithia-treated aluminium oxyhydroxide A10(OH) and / or at least one lithia-treated aluminium hydroxide A1(OH)3.

[0023] According to one or more embodiments, the adsorbent solid comprises, and preferably consists of, lithia-coated bayerite and / or lithia-coated boehmite.

[0024] According to one or more embodiments, the adsorbent solid comprises between 0.1% by weight and 5% by weight of lithium element, preferably in the form of LiCl, relative to the total weight of the adsorbent solid.

[0025] According to one or more embodiments, the adsorbent solid comprises, and preferably consists of, a solid material of formula (LiCl)x.2Al(OH)3,nH2O, in which n is between 0.01 and 10, and x is between 0.4 and 1.

[0026] According to one or more embodiments, the steps of the process are carried out at a temperature (e.g. temperature in the adsorbent solid) between 0°C and 160°C, preferably between 0°C and 120°C and preferably between 5°C and 100°C, particularly preferably between 15°C and 80°C, very preferably between 40°C and 80°C, in particular to promote accelerated perforation of the adsorbent solid.

[0027] According to one or more embodiments, the steps of the process are carried out at a controlled pressure (e.g., pressure in the adsorbent solid) such that the liquid phase remains constant throughout the process according to the invention. According to one or more embodiments, the pressure in the beds of adsorbent solid is between 0.09 MPa and 5 MPa, preferably between 0.095 MPa and 3.5 MPa, preferably between 0.1 MPa and 2.5 MPa.

[0028] According to one or more embodiments, the volume eluted during all the adsorption steps, defined as the number of bed volumes eluted, is between 1 and 100, preferably between 3 and 50.

[0029] According to one or more embodiments, the volume eluted during all the desorption steps divided by the volume eluted during all the adsorption steps is between 0.01 and 2, preferably between 0.05 and 0.5.

[0030] Other features and advantages of the invention according to the aforementioned aspects will become apparent from the following description and non-limiting examples of embodiment, with reference to the figures attached and described below. List of figures

[0031] Fig. 1 represents a lithium adsorption extraction process according to the invention illustrating in particular several extraction columns used in series for the adsorption and desorption substeps.

[0032] Fig. 2 represents a lithium adsorption extraction process according to the invention illustrating in particular periods of adsorption and desorption substeps differentiated by the nature of the input flow and the destination of the output flow. Description of the implementation methods

[0033] Embodiments of the process according to the aforementioned aspects will now be described in detail. In the following detailed description, numerous specific details are presented to provide a more thorough understanding of the process of the invention. However, it will be apparent to those skilled in the art that the process according to the invention can be implemented without these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0034] In this application, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open-ended and does not exclude other unstated elements. It is understood that the term "include" includes the exclusive and closed term "consist." In this application, the terms "elution" and "desorption" are interchangeable; the same applies to the terms "eluent" and "desorbant." Furthermore, in this description, the terms "essentially" or "substantially" correspond to an approximation of ±10%, preferably ±5%. In this application, it is understood that the term "extraction column" may correspond to equipment (e.g., a column) containing a predetermined volume of adsorbent, or to a predetermined volume of adsorbent contained in equipment, such equipment possibly comprising a plurality of such predetermined volumes of adsorbent. Finally, in this description, the... The terms "position" and "arrangement" of the extraction columns used in the description of the steps do not refer to a physical position but to an order of operation of said extraction columns.

[0035] The present invention relates to a lithium adsorption extraction process employing a cascade of alternating bed extraction columns, referred to as "advance-lag" (or "head-train"), for the adsorption and elution phases. Therefore, at least two extraction columns are used in series for adsorption and at least two extraction columns are used in series for elution (desorption).

[0036] In particular, the process of the present invention uses a plurality of extraction columns, each comprising an adsorbent bed and arranged in series, and operating as follows: - a plurality of extraction columns arranged in the adsorption phase, the first extraction column in the adsorption phase (according to the direction of the fluid flow through it) being "ahead" (or upstream) of a second extraction column, which is thus "behind" (or downstream) of the first extraction column (and ahead of a third extraction column, etc., and so on until a final extraction column in the adsorption phase); and - a plurality of extraction columns arranged in the desorption phase, the first extraction column in the desorption phase (according to the direction of the fluid flow through it) being "ahead" of a second extraction column, which is thus "behind" of the first extraction column (and ahead of a third extraction column, etc.).and so on until a final extraction column in the desorption phase).

[0037] The process according to the invention is illustrated by [Fig. 1]. The process comprises a plurality of steps i (4 steps in this example), each step i comprising two substeps a and b corresponding to the adsorption and desorption phases, respectively.

[0038] During the adsorption substep a, a charge F is fed into a (first) plurality of extraction columns C1-C2 (or adsorbent beds) arranged in series. The C1-C2 extraction columns of the adsorption substep a are said to be "in the adsorption phase." In the example in [Fig. 1], the charge F is fed into a first extraction column C1 and then a second extraction column C2 arranged in series (the first being upstream of the second, and so on). As the charge F passes through the adsorbent beds of the C1-C2 extraction columns, the lithium gradually saturates the adsorbent beds. Thus, during substep a, the lithium is progressively adsorbed until potentially reaching a predetermined first lithium content (e.g., saturation) of the first Column C1 (upstream column), referred to as "ahead" (in terms of lithium content), and the second and final extraction column C2 (downstream column) being referred to as "lag". At the outlet of the plurality of extraction columns in sub-step a of the process, a raffinate R depleted in lithium (relative to feed F) is obtained.

[0039] Simultaneously or consecutively with the adsorption substep a, during the desorption substep b, a desorbent (or eluent) D is fed into a (second) plurality of C3-C4 extraction columns (or adsorbent beds) arranged in series. The C3-C4 extraction columns of the adsorption substep b are said to be "in the desorption phase." In the example in [Fig. 1], the desorbent D is fed into a third C3 extraction column and then a fourth C4 extraction column arranged in series. During substep b, the lithium is preferably desorbed progressively to a second predetermined lithium content (e.g., until complete desorption or regeneration) in the third C3 column, referred to as the "lead" column, while the fourth and final C4 extraction column is referred to as the "lag" column. At the outlet of the plurality of extraction columns of substep b of the process, an extract E enriched in lithium (relative to charge F) is obtained.

[0040] During the second step 2: - the extraction column positioned (operated) in "advance" of substep a, i.e., the extraction column presenting the first predetermined content of lithium element (e.g. the Cl extraction column being saturated), is positioned (operated) in "delay" in substep b of desorption (to initiate its desorption / regeneration); - the extraction column in "delay" of substep a, (e.g. the partially saturated C2 extraction column) is placed "ahead" in the adsorption substep a, to reach a first predetermined lithium content (e.g. to complete its saturation); - the extraction column positioned (operated) "ahead" of substep b, i.e., the extraction column presenting the second predetermined lithium content (e.g., the C3 extraction column being regenerated), is positioned (operated) "behind" the adsorption substep a (to initiate its saturation); and - The extraction column that is "lagging" from substep b (e.g., the partially desorbed / regenerated C4 extraction column) is moved "ahead" in the desorption substep b to reach the second predetermined lithium content (e.g., to complete its desorption / regeneration). Thus, from one step to the next, the extraction columns are shifted by a value (i.e., the equivalent of) one extraction column (C1-C4) (in the opposite direction to the flow of fluids through the extraction columns) when moving from one step to the next.

[0041] In the same way as in the second step, in the third step: - the partially regenerated extraction column Cl is placed "ahead" of the desorption substep b to complete its regeneration; - the saturated extraction column C2 is put into "delay" substep b of desorption to initiate its regeneration; - the partially saturated C3 column is advanced in substep a of adsorption to complete its saturation; and - the regenerated column C4 is positioned "late" in the adsorption substep a to initiate its saturation.

[0042] Similarly, during the fourth step: - The regenerated column Cl is positioned "late" in the adsorption substep a to initiate its saturation - the partially regenerated extraction column C2 is placed "ahead" of the desorption substep b to complete its regeneration; - the saturated extraction column C3 is "delayed" in the desorption substep b to initiate its regeneration; and - the partially saturated C4 column is put "ahead" of the adsorption substep a to complete its saturation.

[0043] The cycle then starts again at step 1. Preferably, the cycle comprises as many steps as the number of extraction columns used in the process according to the invention.

[0044] Advantageously, the process according to the invention makes it possible to stiffen the lithium concentration front during the adsorption and desorption phases, leading to gains in the output lithium content and in the process yield.

[0045] Thus, when moving from a (e.g., first) step i to a subsequent (e.g., second) step i+1, the position (the operation) of the extraction columns C1-C4 can be shifted by the equivalent of one C1-C4 extraction column (in the opposite direction to the flow of fluids passing through the extraction columns). In other words, the plurality of C1-C4 extraction columns arranged in series includes feed and withdrawal points that can be shifted over time by a value corresponding to one C1-C4 extraction column to determine a lithium adsorption zone between the injection point of the charge F and the withdrawal point of the raffinate R, and a lithium desorption zone between the injection point of the desorbent D and the withdrawal point of an extract E.Preferably, the time shift is triggered by a predetermined time period (time before switching from one step to another), said predetermined time period being able to be determined for example as a function of the content (e.g. concentration) of lithium at a given position during the process, for example in the solid bed of adsorbent of at least one of the extraction columns C1-C4 and / or in the raffinate R. and / or in extract E. For example, the time shift can be triggered when the first extraction column (e.g., extraction column C1) in the adsorption phase a of a given step i (e.g., the first step 1) has a lithium content greater than or equal to the first predetermined lithium content, and / or when the first extraction column (e.g., extraction column C3) in the desorption phase b of said given step i (e.g., the first step 1) has a lithium content less than or equal to the second predetermined lithium content. In particular, the sequencing of the injection and collection points can take place within a process operating cycle. The cycle time refers to the time it takes for the injection and collection points to be sequenced until they return to their initial position in the process. At the end of a cycle, the process is back in its initial configuration.According to one or more embodiments, a cycle comprises as many steps as there are extraction columns. For example, a cycle of a process according to the invention comprising 4 extraction columns preferably comprises 4 steps.

[0046] According to one or more embodiments, the process uses at least 4 extraction columns, preferably between 4 and 8 extraction columns, preferably between 4 and 6 extraction columns. Preferably, the process uses 4 extraction columns. According to one or more embodiments, the process uses an equal number of extraction columns in the adsorption phase and extraction columns in the desorption phase.

[0047] According to one or more embodiments, the process uses: - two extraction columns positioned in the adsorption phase, i.e., during substep a, where the first extraction column is positioned "ahead" of the second and last extraction column, which is positioned "behind" the first extraction column; and - two extraction columns positioned in the desorption phase, i.e., during substep b, where the first extraction column is positioned "ahead" of the second and last extraction column, which is positioned "behind" the first extraction column.

[0048] According to one or more embodiments, the process uses n extraction columns, of which x extraction columns are positioned in the adsorption phase, i.e., during substep a, and y extraction columns are positioned in the desorption phase, i.e., during substep b, in which: a step i comprises: - an adsorption substep a in which the x extraction columns, referred to as "in the adsorption phase," are fed with at least one charge F comprising lithium, and at least one raffinate R is withdrawn from said x extraction columns in the phase adsorption a, a first extraction column of the x extraction columns in adsorption phase a being arranged upstream with respect to a second extraction column in adsorption phase a (according to the direction of flow of the fluids passing through said x extraction columns in adsorption phase a) and so on up to a last (xith) extraction column in adsorption phase a; and - simultaneously or consecutively to the adsorption substep a, a desorption substep b in which the y extraction columns said "in desorption phase," are fed with at least one desorbent D, and at least one extract E is withdrawn from said y extraction columns in desorption phase b,a first extraction column of the y extraction columns in desorption phase b being arranged upstream with respect to a second extraction column in desorption phase b (according to the direction of the flow of the fluids passing through said y extraction columns in desorption phase b) and so on until a last (yth) extraction column in desorption phase b, a step i+1 consecutive to step i and being carried out (e.g. after the predetermined time period, and / or when the first extraction column of the x extraction columns in adsorption phase a of step i has a lithium element content greater than or equal to a first predetermined lithium element content, and / or when the first extraction column in desorption phase b of step i has a lithium element content less than or equal to a second predetermined lithium element content),step i+1 repeating the adsorption substeps a and desorption substeps b of step i and in which the position of the n extraction columns is shifted by a value of one extraction column such that: , - the first extraction column of the x extraction columns in the adsorption phase a of step i is positioned as the last extraction column of the y extraction columns in the desorption phase b of step i+1; - the second extraction column of the x extraction columns in adsorption phase a of step i is positioned as the first extraction column of the x extraction columns in adsorption phase a of step i+1; and (and so on until) - the last extraction column of the x extraction columns in adsorption phase a of step i is positioned as the penultimate extraction column of the x extraction columns in adsorption phase a of step i+1; - the first extraction column of the y extraction columns in the desorption phase b of step i is positioned as the last extraction column of the x extraction columns in the adsorption phase a of step i+1; - the second extraction column of the y extraction columns in desorption phase b of step i is positioned as the first extraction column of the y extraction columns in desorption phase b of step i+1; and (and so on up to) - the last extraction column of the y extraction columns in desorption phase b of step i is positioned as the penultimate extraction column of the y extraction columns in desorption phase b of step i+1.

[0049] According to one or more embodiments, n is (an integer) greater than or equal to 4, preferably n is between 4 and 8, preferably n is between 4 and 6, preferably n is equal to 4. According to one or more embodiments, x and / or y is (an integer) greater than or equal to 2, preferably x and / or y is between 2 and 4, preferably x and / or y is equal to 2 or 3, preferably x and / or y is equal to 2. Preferably, n is equal to the sum of x and y, and x is equal to y. According to one or more embodiments, i is (an integer) between (ranging from) 1 and n.

[0050] With reference to [Fig.2], according to one or more embodiments, substep a and / or substep b may include several periods (time periods), each period being differentiated by the nature (i.e., lithium content) of the inlet flow (the charge F and / or the desorbant D) and / or the nature (i.e., lithium content) of the outlet flow (the raffinate R and / or the extract E), the position (i.e., the order of operation) of the columns during substeps a and b remaining unchanged / identical.

[0051] In this example of [Fig. 2], during the first step 1, periods i and ii of substep a correspond to the adsorption periods where at least one charge (F1, F2) passes through the extraction columns Cl and C2 and where lithium is progressively adsorbed until saturation of the extraction column Cl positioned in the "advance" position. Periods i and ii differ in particular by the destination (e.g., the lithium content) of the output stream, i.e., the raffinate R. In particular, a first raffinate RI extracted during the first period i can be partially or completely recycled as a desorbent for the desorption substep b, and the second raffinate R2 constitutes the lithium-depleted output stream (relative to charge F) of the process according to the invention. Similarly, the nature of the Fl and F2 charges can vary between periods i and ii of substep a (for example, the first extract El could be sent as the second charge F2).

[0052] Simultaneously or consecutively, during the first step 1, periods i and ii of substep b correspond to the desorption periods where at least one desorbent (D1, D2) passes through the extraction columns C3 and C4 and where lithium is progressively desorbed until the extraction column C3, positioned in "advance," is regenerated. Periods i and ii differ in particular by the destination (e.g., the lithium content) of the inlet and / or outlet stream, i.e., the desorbent D and / or the extract E. In particular, a first extract E1 is extracted during the first period i can be partially or completely recycled as feed F for the adsorption substep a, the second extract E2 constituting the lithium-enriched output stream (relative to feed F) of the process according to the invention. Similarly, the nature of the desorbent DI and D2 can vary between periods i and ii of substep b (for example, the first raffinate RI could be sent as the first desorbent El).

[0053] According to one or more embodiments, the feed comprises and preferably consists of a (saline) solution containing lithium and which may or may not be saturated with salts, such as a brine.

[0054] According to one or more embodiments, the charge comprises at least one of the following elements B: Na, K, Rb, Cs, Mg, Ca, Sr, Ba, F, Cl, Br, I, SO4, CO3, NO3, B and HCO3.

[0055] Said charge can be any natural saline solution, concentrated or obtained from a lithium extraction or processing method. For example, said saline solution used in the extraction method according to the invention can advantageously be chosen from brines from salt lakes or geothermal springs, brines subjected to evaporation to obtain concentrated lithium brines, seawater, effluents from lithium chloride or lithium hydroxide production plants and effluents from lithium extraction processes from minerals.

[0056] According to one or more embodiments, the charge comprises at least 0.05 g / L by weight of lithium element, preferably in the form of LiCl. According to one or more embodiments, the charge comprises between 0.1 g / L and 1 g / L of lithium element, preferably in the form of LiCl.

[0057] Advantageously, the process according to the invention allows the separation of lithium from alkali metals, preferably sodium (Na) and potassium (K), and from alkaline earth metals, preferably magnesium (Mg), calcium (Ca), and strontium (Sr), which are generally present in significant quantities in the saline solutions treated in said extraction process. The process according to the invention also allows the selective separation of lithium from other compounds such as boron and sulfates.

[0058] According to one or more embodiments, the desorbent is selected from the group consisting of water, lithium water, brine, preferably water. According to one or more embodiments, the desorbent comprises between 0 g / L and 1 g / L of lithium element, preferably in the form of LiCl, relative to the total weight of the desorbent. According to one or more embodiments, the desorbent comprises less than 0.05 g / L of lithium element, preferably less than 0.01 g / L of lithium element, relative to the total weight of the desorbent.

[0059] According to one or more embodiments, the adsorbent solid comprises at least one lithiatic aluminum oxyhydroxide A10(OH) and / or at least one lithiatic aluminum hydroxide A1(OH)3. According to one or more embodiments, the at least A lithium-containing aluminum oxyhydroxide A10(OH) comprises lithium-containing boehmite. According to one or more embodiments, at least one lithium-containing aluminum oxyhydroxide A10(OH) comprises at least 60% by weight, preferably at least 80% by weight, of lithium-containing boehmite, relative to the total weight of at least one lithium-containing aluminum oxyhydroxide A10(OH). According to one or more embodiments, at least one lithium-containing aluminum oxyhydroxide A10(OH) consists of lithium-containing boehmite.

[0060] According to one or more embodiments, the at least one lithiased aluminum hydroxide A1(OH)3 comprises lithiased bayerite. According to one or more embodiments, the at least one lithiased aluminum hydroxide A1(OH)3 comprises at least 60% by weight, preferably at least 80% by weight, of lithiased bayerite, relative to the total weight of the at least one lithiased aluminum hydroxide A1(OH)3. According to one or more embodiments, the at least one lithiased aluminum hydroxide A1(OH)3 consists of lithiased bayerite.

[0061] According to one or more embodiments, the adsorbent solid (e.g., fresh) comprises at least 0.1% by weight of lithium (preferably in the form of LiCl), preferably at least 1% by weight, and most preferably at least 1.5% by weight, relative to the total weight of the adsorbent solid. According to one or more embodiments, the adsorbent solid comprises between 0.1% by weight and 5% by weight of lithium (preferably in the form of LiCl), preferably between 1% by weight and 4% by weight, and most preferably between 1.5% by weight and 3% by weight, relative to the total weight of the adsorbent solid.

[0062] According to one or more embodiments, the adsorbent solid comprises and preferably consists of a solid material of formula (LiCl)x.2Al(OH)3,nH2O, in which n is between 0.01 and 10, and x is between 0.4 and 1. According to one or more embodiments, n is between 0.1 and 5, preferably between 0.1 and 1, most preferably between 0.1 and 0.5.

[0063] According to one or more embodiments, the adsorbent solid has a specific surface area characterized by nitrogen adsorption according to the BET method of between 1 m2 / g and 30 m2 / g, preferably between 1 m2 / g and 20 m2 / g.

[0064] According to one or more embodiments, the adsorbent solid is in the form of beads or extrudates of cylindrical, hollow cylinder, wheel-shaped, trilobed or multilobed shape, or any other geometric shape understood by those skilled in the art. According to one or more embodiments, the adsorbent solid is in the form of beads with an average diameter of between 0.1 mm and 1.5 mm, preferably between 0.1 mm and 1 mm, and more preferably between 0.3 mm and 0.8 mm. According to one or more embodiments, the adsorbent solid is in the form of extruded shapes with diameters between 0.15 mm and 5 mm, preferably between 0.2 mm and 3 mm, more preferably between 0.5 mm and 1.0 mm.

[0065] The solid adsorbent material is characterized using the following techniques: nitrogen adsorption for determining the specific surface area according to the BET method (e.g., ASTM D 3663-7); and X-ray fluorescence for elemental analysis. The average diameter of the extrudates is measured optically on at least 10 extrudates, preferably at least 50. For example, when the solid adsorbent is in the form of beads, the number-average diameter of the adsorbent solid is estimated by analyzing the particle size distribution of a sample of at least 50 adsorbent beads using imaging according to ISO 13322-2:2006, with a conveyor belt allowing the sample to pass in front of the camera lens. The number-average diameter is then calculated from the particle size distribution by applying ISO 9276-2:2001.

[0066] According to one or more embodiments, the temperature is set so that the temperature in the adsorbent solid remains between 0°C and 160°C, preferably between 0°C and 120°C and preferably between 5°C and 100°C, particularly preferably between 15°C and 80°C, very preferably between 40°C and 80°C, in particular to promote accelerated perforation of the adsorbent solid.

[0067] Advantageously, the pressure is regulated so that the liquid phase remains constant throughout the process according to the invention. According to one or more embodiments, the pressure in the adsorbent solid is between 0.09 MPa and 5 MPa, preferably between 0.095 MPa and 3.5 MPa, preferably between 0.1 MPa and 2.5 MPa.

[0068] According to one or more embodiments, the volume eluted during all the adsorption steps, defined as the number of bed volumes eluted, is between 1 and 100, preferably between 3 and 50.

[0069] According to one or more embodiments, the volume eluted during all the desorption steps divided by the volume eluted during all the adsorption steps is between 0.01 and 2, preferably between 0.05 and 0.5.

[0070] According to one or more embodiments, the flows pass through the columns preferentially in downward mode. Examples

[0071] Comparative example of a separation: - without shifting of the adsorption and desorption phases (reference process A); - with phase shift of adsorption (reference process B), i.e., with the presence of sub-steps a and without the presence of sub-steps b; - with a shift in the adsorption and desorption phases (process C according to the invention), i.e., with the presence of substeps a and b as illustrated in [Fig.2].

[0072] The process according to the invention is applied for the purification and separation of a lithium brine of the following composition: - 0.4 g / L of lithium element; - 110 g / L as chlorine; - 70 g / L as elemental sodium

[0073] The adsorbent considered for the separation is a lithia-coated bayerite.

[0074] The process temperature is 20°C. The desorbent is water containing 0.15 g / L of lithium. The beds are traversed in downward flow for both the adsorption and desorption phases. The volume eluted by adsorption corresponds to 5.5 bed volumes. The volume eluted by desorption corresponds to 2.5 bed volumes.

[0075] In process A (reference) adsorption is carried out with a first column and desorption is carried out with a second column.

[0076] In process B (reference), an adsorption substep a is carried out with two extraction columns in series. Desorption is carried out with a single column (no substep b). The process comprises 5 periods. In particular, substep a is divided into two periods to produce a first raffinate (first period) recycled as a desorbent, and a second raffinate (second period) constituting the lithium-depleted output stream. Furthermore, desorption is divided into three periods to produce a first extract (first period) recycled as a feedstock, a second extract (second period) constituting the lithium-enriched extract, the product of interest, and a third extract (third period) recycled as a desorbent.

[0077] In process C (the invention), adsorption is carried out in substeps a and b, each using two columns in series (4 columns used). The process comprises 4 substeps. RI is recycled as desorbent D. R2 constitutes the lithium-depleted output stream. E1 is recycled as charge F. E2 constitutes the extract, the lithium-enriched product of interest.

[0078] Table 1 compares the performance of the two processes. The lithium yield corresponds to the mass of lithium recovered in the extract relative to the mass of lithium entering the process.

[0079] [Tables 1] Process Concentration of Lithium Extract Lithium Yield Process A 1.00 g / L 67.4% Process B 1.30 g / L 92.2% Process C 1.40 g / L 93.2%

[0080] The process according to the invention makes it possible to increase both the lithium yield and the concentration of the lithium extract.

Claims

1. Demands A lithium adsorption extraction process, using a plurality of extraction columns (C1-C4), each comprising a bed of adsorbent solid and arranged in series, of which a plurality of extraction columns (C1-C4) are positioned in the adsorption phase and a plurality of extraction columns (C1-C4) are positioned in the desorption phase (C1-C4), comprising the following steps: a step i comprising: - an adsorption substep (a) in which extraction columns (C1-C4), referred to as "in the adsorption phase," are fed with at least one charge (F) comprising lithium, and at least one raffinate (R) is withdrawn from said extraction columns (C1-C4) in the adsorption phase (a), a first extraction column of the extraction columns (C1-C4) in the adsorption phase (a) being arranged upstream of a last extraction column in the adsorption phase (a); and - simultaneously or consecutively to the adsorption substep (a), a desorption substep (b) in which extraction columns (C1-C4), referred to as "in desorption phase," are fed with at least one desorbent (D), and at least one extract (E) is withdrawn from said extraction columns (C1-C4) in desorption phase (b), a first extraction column of the extraction columns (C1-C4) in desorption phase (b) being arranged upstream with respect to a last extraction column in desorption phase (b), a step i+1 consecutive to step i and repeating the adsorption (a) and desorption (b) substeps of step i and in which the position of the extraction columns (C1-C4) is shifted by the value of one extraction column (C1-C4) such that: - the first extraction column of the extraction columns (C1-C4) in the adsorption phase (a) of step i is positioned as the last extraction column of the extraction columns in the desorption phase (b) of step i+1; - a second extraction column of the extraction columns (Cl-C4) in the adsorption phase (a) of step i is positioned as the first extraction column of the extraction columns in the adsorption phase (a) of step i+1;

2. - the first extraction column of the extraction columns (C1-C4) in the desorption phase (b) of step i is positioned as the last extraction column of the extraction columns in the adsorption phase (a) of step i+1; and - a second extraction column of the extraction columns (Cl-C4) in the desorption phase (b) of step i is positioned as the first extraction column of the extraction columns in the desorption phase (b) of step i+1. A method according to claim 1 comprising at least the following steps: a first step (1) comprising: - an adsorption substep (a) in which the plurality of extraction columns (Cl, C2) referred to as "in adsorption phase" are fed with at least one charge (F) comprising lithium, and at least one raffinate (R) is withdrawn from said extraction columns (Cl, C2) in adsorption phase (a), a first extraction column (Cl) in adsorption phase (a) being arranged upstream with respect to a last extraction column (C2) in adsorption phase (a) according to the direction of the flow of the fluids passing through said extraction columns (Cl, C2) in adsorption phase (a);and - simultaneously or consecutively to the adsorption substep (a), a desorption substep (b) in which the plurality of extraction columns (C3, C4) referred to as "in desorption phase," are fed with at least one desorbant (D), and at least one extract (E) is withdrawn from said extraction columns (C3, C4) in desorption phase (b), a first extraction column (C3) in desorption phase (b) being upstream with respect to a last extraction column (C4) in desorption phase (b) according to the direction of the flow of the fluids passing through said extraction columns (C3, C4) in desorption phase (b); a second step (2) following the first step (1) and repeating the adsorption (a) and desorption (b) substeps of the first step (1) and in which: - the first extraction column (Cl) in the adsorption phase (a) of the first step (1) is positioned as the last extraction column (Cl) in the desorption phase (b) of the second step (2); - the second extraction column (C2) in the adsorption phase (a) of the first step (1) is positioned as the first extraction column (C2) in the adsorption phase (a) of the second step (2); - the first extraction column (C3) in the desorption phase (b) of the first step (1) is positioned as the last extraction column (C3) in the adsorption phase (a) of the second step (2); and - the second extraction column (C4) in the desorption phase (b) of the first step (1) is positioned as the first extraction column (C4) in the desorption phase (b) of the second step (2).

3. A method according to claim 2, comprising a third step (3) following the second step (2) and incorporating the adsorption (a) and desorption (b) substeps of the second step (2), wherein: - the first extraction column (C2) in the adsorption phase (a) of the second step (2) is positioned as the last extraction column (C2) in the desorption phase (b) of the third step (3); - the second extraction column (C3) in the adsorption phase (a) of the second step (2) is positioned as the first extraction column (C3) in the adsorption phase (a) of the third step (3); - the first extraction column (C4) in the desorption phase (b) of the second step (2) is positioned as the last extraction column (C4) in the adsorption phase (a) of the third step (3);and - the second extraction column (Cl) in the desorption phase (b) of the second step (2) is positioned as the first extraction column (Cl) in the desorption phase (b) of the third step (3).;

4. A method according to claim 3, comprising a fourth step (4) consecutive to the third step (3) and incorporating the substeps of adsorption (a) and desorption (b) of the third step (3), wherein: - the first extraction column (C3) in the adsorption phase (a) of the third step (3) is positioned as the last extraction column (C3) in the desorption phase (b) of the fourth step (4); - the second extraction column (C4) in the adsorption phase (a) of the third step (3) is positioned as the first extraction column (C4) in the adsorption phase (a) of the fourth step (4); - the first extraction column (Cl) in the desorption phase (b) of the third step (3) is positioned as the last extraction column (Cl) in the adsorption phase (a) of the fourth step (4); and - the second extraction column (C2) in the desorption phase (b) of the third step (3) is positioned as the first extraction column (C2) in the desorption phase (b) of the fourth step (4).

5. A method according to claim 4, wherein the first step (1) is subsequent to the fourth step (4) and incorporates the adsorption (a) and desorption (b) substeps of the fourth step (4), wherein: - the first extraction column (C4) in the adsorption phase (a) of the fourth step (4) is positioned as the last extraction column (C4) in the desorption phase (b) of the first step (1); - the second extraction column (Cl) in the adsorption phase (a) of the fourth step (4) is positioned as the first extraction column (Cl) in the adsorption phase (a) of the first step (1); - the first extraction column (C2) in the desorption phase (b) of the fourth step (4) is positioned as the last extraction column (C2) in the adsorption phase (a) of the first step (1); and - the second extraction column (C3) in desorption phase (b) of the fourth step (4) is positioned as the first extraction column (C3) in desorption phase (b) of the first step (1).

6. A method according to any one of the preceding claims, comprising an n-step cycle, wherein at the end of step n, the extraction columns (C1-C4) of step n are repositioned to their original positions of step 1.

7. A method according to any one of the preceding claims, wherein n is greater than or equal to 4, preferably n is between 4 and 8, preferably n is between 4 and 6, preferably n is equal to 4.

8. A method according to any one of the preceding claims, wherein n is equal to 4, two extraction columns (C1-C4) being positioned in the adsorption phase (a) and two extraction columns (C1-C4) being positioned in the adsorption phase (b).

9. A method according to any one of the preceding claims, wherein at least one adsorption substep (a) and / or at least one desorption substep (b) comprises at least two periods, each period being differentiated from another period by the lithium content of the feed (F) and / or desorbant (D) fed and / or raffinate (R) and / or extract (E) withdrawn, the position (the order of operation) of the extraction columns (C1-C4) during said adsorption substep (a) and / or desorption substep (b) being unchanged.

10. A process according to any one of the preceding claims, wherein at least one adsorption substep (a) comprises at least two periods, wherein a first raffinate (RI) withdrawn during a first period (i) is removed from the process or is at least partially recycled as a desorbent (D), and a second raffinate (R2) withdrawn during a second period (ii) is removed from the process as a lithium-depleted output stream.

11. A process according to any one of the preceding claims, wherein at least one desorption substep (b) comprises at least two periods, wherein a first extract (E1) withdrawn during a first period (i) is removed from the process or is optionally at least partially recycled as a feed (F), and wherein a second extract (E2) withdrawn during a second period (ii) is removed from the process as a lithium-enriched output stream.

12. A method according to any one of the preceding claims, wherein the charge (F) comprises, and preferably consists of, a lithium-containing, salt-saturated solution.

13. A method according to any one of the preceding claims, wherein the desorbent (D) is chosen from the group consisting of water, lithiated water, brine, preferably water.

14. A method according to any one of the preceding claims, wherein the adsorbent solid comprises at least one oxyhydroxide

15. of lithia aluminum A10(OH) and / or at least one lithia aluminum hydroxide A1(OH)3. A process according to any one of the preceding claims, wherein the process steps are carried out at a temperature between 0°C and 160°C, and / or at a pressure in the beds of solid adsorbent between 0.09 MPa and 5 MPa.

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