Simulated moving bed extraction of lithium by adsorption, with extract recycling

Abstract

Process and device for simulated moving bed extraction of lithium by adsorption, in which at least one column (Ci) is supplied with a feed (F) comprising lithium and a desorbent (D), and an extract (E) and a raffinate (R) are withdrawn from the column. The column comprises an adsorbent solid (Ai) and is configured to operate in a closed loop. The supply and withdrawal points of the column are shifted over time by a value corresponding to a predetermined quantity of adsorbent solid with a permutation period and determine a plurality of operating zones of the column, in particular the following main zones: a lithium desorption zone I; a desorption zone II of compounds other than lithium; and a lithium adsorption zone III. According to the invention, a portion of the extract is recycled to the feed.

Description

[0001] Method and apparatus for lithium adsorption extraction in a simulated moving bed with extract recycling

[0002] technical field

[0003] The present invention relates to the field of lithium adsorption extraction in a simulated moving bed.

[0004] Previous technique

[0005] Demand for lithium has increased sharply in recent years, largely due to the rise of electric vehicles. To meet this demand, improving existing lithium extraction processes is essential. Lithium can be extracted from rocks or brines. In the case of brines, traditional processes are based on open-air evaporation, a slow and low-yield method. Adsorption processes have recently been developed and offer promising prospects.

[0006] 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.

[0007] This type of adsorbent can be used in cyclic adsorption and elution processes in which the brine passes through a column on which the lithium is captured, the latter then being fed with an eluent to desorb the desired lithium.

[0008] More advanced implementations are also possible. Patent FR3131225B1 proposes, in particular, the use of a simulated moving bed to extract lithium while simultaneously purifying it and delivering a more concentrated flow, thus reducing the energy requirements of the downstream water evaporation stages. Patent FR3131225B1 further indicates that up to 20% of the extract can be recycled within Zone II, preferably in the middle of Zone II.

[0009] However, the extraction by adsorption of lithium in a simulated moving bed can be improved.

[0010] Summary of the invention

[0011] 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 method and device for lithium adsorption extraction in a simulated moving bed, enabling an increased concentration of lithium in the extract. The high concentration of lithium in the extract notably reduces the amount of water to be evaporated or separated later in the process, thus simplifying the extraction device equipment and resulting in significant energy savings.

[0012] Advantageously, the applicant identified that recycling a portion of the extract as part of the feed to be processed by the simulated moving bed lithium adsorption extraction process and device made it possible to increase the lithium concentration in the extract and reduce the amount of water to be evaporated or separated.

[0013] According to a first aspect, the aforementioned objects, as well as other advantages, are obtained by a simulated moving bed lithium adsorption extraction process comprising the following step: at least one column is fed with at least one charge comprising lithium and a desorbent, and at least one extract and at least one raffinate are withdrawn from the column, the at least one column comprising an adsorbent solid, the at least one column being interconnected in a closed loop, the feeding and withdrawal points of the at least one column being shifted over time by a value corresponding to a predetermined quantity of adsorbent solid with a permutation period and determining a plurality of column operating zones, and in particular the following main zones designated by definition by a number: a lithium desorption zone I comprising a desorbent injection point and an extract withdrawal point;a zone II for the desorption of alkali metals other than lithium and / or alkaline earth metals located between the point of withdrawal of the extract and a point of injection of the feed including lithium; a zone III for the adsorption of lithium located between the point of injection of the feed and a point of withdrawal of the raffinate; and a zone IV is located between the point of withdrawal of the raffinate and the point of injection of the desorbent, a process in which a part of the extract is recycled to the feed.

[0014] According to one or more embodiments, at least one column comprises a plurality of interconnected columns or adsorbers in a closed loop, the supply and withdrawal points of the columns or adsorbers being shifted over time by a value corresponding to one column or adsorber.

[0015] According to one or more embodiments, the plurality of columns or adsorbers comprises at least 4 columns or adsorbers, preferably between 4 and 24 columns or adsorbers, preferably between 8 and 21 columns or adsorbers, for example between 12 and 15 columns or adsorbers.

[0016] According to one or more embodiments, the adsorbent solid is distributed in zones I to IV according to configurations of type a / b / c / d, that is to say that the distribution of the adsorbent solid, in relation to the total quantity of adsorbent solid, is as follows: a is the quantity of adsorbent solid in zone I; b is the quantity of adsorbent solid in zone II; c is the quantity of adsorbent solid in zone III; and d is the quantity of adsorbent solid in zone IV, and: a = 43% ± 9%; b = 29% ± 6%; c = 14% ± 3%; and d = 14% ± 3%.

[0017] According to one or more embodiments, the at least one column comprises a plurality of beds of solid adsorbent interconnected in a closed loop and separated by trays, the feeding and withdrawal points in the trays of the column being offset over time by a value corresponding to one bed of adsorbent.

[0018] According to one or more embodiments, at least one column comprises at least 4 beds of solid adsorbent, preferably between 4 and 24 beds of solid adsorbent, preferably between 8 and 21 beds of solid adsorbent, for example between 12 and 15 beds of solid adsorbent.

[0019] According to one or more embodiments, the beds of solid adsorbent are distributed in zones I to IV according to configurations of type a / b / c / d, that is to say that the distribution of the beds of solid adsorbent is as follows: a is the number of beds in zone I; b is the number of beds in zone II; c is the number of beds in zone III; and d is the number of beds in zone IV, and: a = (t * 0.43) * (1 ± 0.20); b = (t * 0.29) * (1 ± 0.20); c = (t * 0.14) * (1 ± 0.20); and d = (t * 0.14) * (1 ± 0.20), t (the number of beds) being a natural integer between 4 and 24, preferably between 8 and 21, for example between 12 and 15 beds of solid adsorbent.

[0020] According to one or more embodiments, the adsorbent solid comprises at least one lithiaated aluminium oxyhydroxide Al0(OH) and / or at least one lithiaated aluminium hydroxide Al(OH)a.

[0021] According to one or more embodiments, the adsorbent solid comprises and preferably consists of lithium bayerite and / or lithium boehmite.

[0022] 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.

[0023] 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, where n is between 0.01 and 10, and x is between 0.4 and 1.

[0024] According to one or more embodiments, the desorbent is chosen from the group consisting of water, lithia water, brine, preferably water.

[0025] 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.

[0026] According to one or more embodiments, the charge comprises at least 0.05 g / L weight of lithium element, preferably in the form of LiCl, relative to the total weight of the charge.

[0027] 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.

[0028] Advantageously, the process steps 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. In one or more embodiments, the pressure in the adsorbent solid beds is between 0.09 MPa and 5 MPa, preferably between 0.095 MPa and 3.5 MPa, and preferably between 0.1 MPa and 2.5 MPa. In one or more embodiments, the cycle time is at least 20 minutes, preferably at least 40 minutes, such that it is between 1 and 10 hours. Preferably, the cycle time is between 2 and 8 hours.

[0029] According to one or more embodiments, the ratio of the volumetric flow rate of the desorbent to the volumetric flow rate of the charge is less than 1, preferably less than 0.5, preferably less than 0.2, very preferably less than 0.1.

[0030] According to one or more embodiments, the ratio of the volumetric flow rate of the desorbent to the volumetric flow rate of the charge is between 0.01 and 1.0, preferably between 0.02 and 0.5, very preferably between 0.06 and 0.1.

[0031] According to a second aspect, the aforementioned objects, as well as other advantages, are obtained by a simulated moving bed lithium adsorption extraction device comprising the following elements: at least one column adapted to be fed with at least one charge comprising lithium and a desorbent, and to be withdrawn of at least one extract and at least one raffinate from the column, the at least one column comprising a solid adsorbent, the at least one column being interconnected in a closed loop, the feeding and withdrawal points of the at least one column being shifted over time by a value corresponding to a predetermined quantity of solid adsorbent with a permutation period and determining a plurality of operating zones of the at least one extraction column,and in particular the following main zones, designated by definition by a number: a lithium desorption zone I located between a desorbent injection point and an extract withdrawal point; a desorption zone II of alkali metals other than lithium and / or alkaline earth metals located between the extract withdrawal point and a feed injection point containing lithium; a lithium adsorption zone III located between the feed injection point and a raffinate withdrawal point; and a zone IV located between the raffinate withdrawal point and the desorbent injection point, the device comprising a conduit adapted to recycle a portion of the extract to feed at least one column. Other features and advantages of the invention, according to the aforementioned aspects, will become apparent from the following description and non-limiting examples of embodiments.with reference to the attached figures described below.

[0032] List of figures

[0033] Figure 1 represents a simulated moving bed lithium adsorption extraction process according to the invention, using a plurality of columns or adsorbers.

[0034] Figure 2 represents a simulated moving bed lithium adsorption extraction process according to the invention, illustrating the recycling of part of the extract back to the feed.

[0035] Description of the implementation methods

[0036] Embodiments of the device and method 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 device and method. However, it will be apparent to those skilled in the art that the device and method 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.

[0037] In this application, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open-ended, not excluding other unstated elements. It is understood that the term "include" includes the exclusive and closed term "consist." Furthermore, in this description, the terms "essentially" or "substantially" correspond to an approximation of ±10%, preferably ±5%.

[0038] The present invention relates to a lithium adsorption extraction process employing a simulated countercurrent chromatography or simulated moving bed separation process, which we will hereafter collectively refer to as the "LMS" process. The lithium adsorption extraction process by simulated countercurrent chromatography or simulated moving bed described in this application may employ synchronous movement of the inlet / outlet lines, but may also employ asynchronous movement of the inlet / outlet valves in a multicolumn system, the latter being also known as VARICOL. In particular, the sequencing of injection and collection points takes place over one operating cycle of the device. Hereafter, the cycle time refers to the time it takes for the injection and collection points to be sequenced until they return to their initial positions within the device.At the end of a cycle, the device returns to its initial configuration. According to one or more embodiments, a cycle comprises as many periods as there are columns or beds of adsorbent solid in the separation loop. For example, a cycle of an "LMS" process according to the invention, comprising 8 columns or 8 beds of adsorbent solid, consists of 8 periods.

[0039] According to the invention, the LMS method and device uses / includes at least one column (or adsorbers), the column(s) arranged in series implementing a flow of fluids in a medium of solid particles, called the adsorbent solid or granular medium, in a flow direction of the fluid(s) implemented in the column(s). The fluid passing through the column(s) Ci successively is called the main fluid to distinguish it from other secondary fluids that can be added to the main fluid via a distribution and collection device (e.g., valve systems external to the column(s)), generally located at the column inlet or outlet, for example, between two successive columns.

[0040] With reference to Figure 1, according to one or more embodiments, the method and device according to the invention uses / comprising a plurality n of columns Ci (i.e., from column Ci to column C). nseparated by N dispensing devices (for the charge F and the desorbent D) and collection devices (for the extract E and the raffinate R). Preferably, the number n of columns Ci and the number N of dispensing and collection devices are identical. In one or more embodiments, n is greater than or equal to 4. In one or more embodiments, n is between 4 and 24, preferably between 8 and 21, e.g., between 12 and 15. In one or more embodiments, N is greater than or equal to 4. In one or more embodiments, N is between 4 and 24, preferably between 8 and 21, e.g., between 12 and 15.

[0041] Referring to Figure 2, the LMS process and apparatus uses / includes a column Ci implementing the flow of fluids through a plurality of beds of adsorbent solid Ai arranged in series according to the flow direction of the fluid(s) implemented in the column. The fluid successively passing through the beds of adsorbent solid Ai is called the main fluid to distinguish it from secondary fluids that can be added to the main fluid via a distribution and collection device, also called a tray Pi, generally located between two successive beds of adsorbent solid Ai.

[0042] A Pi tray includes at least one collection zone and a valve system for collecting the main fluid and / or injecting secondary fluids and mixing these secondary fluids with the main fluid. A tray also includes at least one distribution zone for distributing the fluid resulting from the mixing of the main fluid and secondary fluids onto the granular bed located immediately downstream, in the direction of the main fluid flow.

[0043] Referring to Figure 2, a column is divided into a plurality of trays Pi and adsorbent beds Ai, with tray Pi positioned directly upstream of the adsorbent bed Ai, in the direction of the main fluid flow. Furthermore, the term adsorbent bed Ai+1 refers to the next adsorbent bed located downstream of the adsorbent bed Ai, in the direction of the main fluid flow. Similarly, tray Pi+1 refers to the next tray located downstream of tray Pi, in the direction of the main fluid flow.

[0044] According to one or more embodiments, the method and device according to the invention use / comprising at least one separation column Ci divided into n beds of adsorbent solid Ai separated by N trays (defining interbed zones), each tray being itself divisible into several sectors or regions, called panels. Preferably, the number n of beds of adsorbent solid Ai and the number N of trays Pi are identical. According to one or more embodiments, n is greater than or equal to 4. According to one or more embodiments, n is between 4 and 24, preferably between 8 and 21, e.g., between 12 and 15. According to one or more embodiments, N is between 4 and 24, preferably between 8 and 21, e.g., between 12 and 15.

[0045] In the following text, the term "step" refers to an operation or group of similar operations performed on a given flow at a specific point in the process. The process is described in its various steps, taken in the order in which the flows or products occur.

[0046] With reference to Figure 1, the simulated moving bed lithium adsorption extraction process according to the invention comprises the following step: one or more column(s) Ci are fed with at least one charge F comprising lithium, denoted element A in Figure 1, and at least one alkali metal other than lithium and / or at least one alkaline earth metal, denoted element B in Figure 1; one or more column(s) Ci are fed with a desorbent D; at least one extract E is withdrawn from column Ci; at least one raffinate R is withdrawn from column Ci, the column(s) Ci comprising an adsorbent solid, in which a portion of the extract E is recycled to the charge F.

[0047] Referring to Figure 1, in one or more embodiments, the adsorbent solid is distributed in the plurality of columns Ci (e.g., adsorbers). Referring to Figure 2, in one or more embodiments, the adsorbent solid is distributed in the adsorbent solid beds Ai of at least one column Ci, the adsorbent solid beds Ai being separated by trays Pi.

[0048] According to the invention, the column or columns Ci is / are interconnected in a closed loop, the supply and withdrawal points of the column(s) Ci being offset over time (for example by a value corresponding to a column (e.g.adsorber) or an adsorbent bed of a column) with a permutation period and determining a plurality of operating zones of the column(s) Ci, and in particular the following main zones designated by definition by a number: a lithium desorption zone I between a desorbent injection point D and an extract withdrawal point E; a non-lithium alkali metal desorption zone II between the extract withdrawal point E and a feed F injection point including lithium; a lithium adsorption zone III between the feed F injection point and a raffinate withdrawal point R, zone III being fed by the feed F as shown in Figure 1; and a zone IV between the raffinate withdrawal point R and the desorbent injection point D;.

[0049] With reference to Figure 1, according to one or more embodiments, the feed and withdrawal points of the columns Ci are shifted over time by a value corresponding to a column Ci (e.g., an adsorber).

[0050] With reference to Figure 2, according to one or more embodiments, the feed and withdrawal points of at least one column Ci are shifted over time by a value corresponding to an adsorbent bed Ai.

[0051] 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.

[0052] In particular, the process according to the invention makes it possible to produce a lithium extract more concentrated than conventional processes. A lithium concentration factor greater than 15 between the feed and the extract is achievable with the process according to the invention, whereas conventional processes are limited to 12.

[0053] In one or more embodiments, the method / device implements / includes a plurality of interconnected columns or adsorbers in a closed loop. In one or more embodiments, the inlet and outlet points of the columns Ci or adsorbers are offset over time by a value corresponding to one column or adsorber. In one or more embodiments, the method / device implements / includes at least 4 columns or adsorbers, preferably between 4 and 24 columns or adsorbers, preferably between 8 and 21 columns or adsorbers, e.g., between 12 and 15 columns or adsorbers.

[0054] According to one or more embodiments, the adsorbent solid is distributed in zones I to IV according to configurations of type a / b / c / d, that is to say that the distribution of the adsorbent solid, in relation to the total quantity of adsorbent solid, is as follows: a is the quantity of adsorbent solid in zone I; b is the quantity of adsorbent solid in zone II; c is the quantity of adsorbent solid in zone III; and d is the quantity of adsorbent solid in zone IV, with: a = 43% ± 9%, preferably ± 6%, very preferably ± 3%; b = 29% ± 6%, preferably ± 4%, very preferably ± 2%; c = 14% ± 3%, preferably ± 2%, very preferably ± 1%; and d = 14% ± 3, preferably ± 2%, most preferably ± 1%.

[0055] In one or more embodiments, the column or columns Ci comprise a plurality of beds of adsorbent solid Aj interconnected in a closed loop and separated by trays Pj, the feed and withdrawal points in the trays Pj of the column Ci being offset over time by a value corresponding to one bed of adsorbent. In one or more embodiments, at least one column Ci comprises between 4 and 24 beds of adsorbent solid Ai, preferably between 8 and 21 beds of adsorbent solid Ai.

[0056] According to one or more embodiments, the beds of solid adsorbent Ai are distributed in zones I to IV according to configurations of type a / b / c / d, that is to say that the distribution of the beds of solid adsorbent Ai is as follows: a is the number of beds in zone I; b is the number of beds in zone II; c is the number of beds in zone III; and d is the number of beds in zone IV, with: a = (t * 0.43) * (1 ± 0.20, preferably 1 ± 0.10, most preferably 1 ± 0.05); b = (t * 0.29) * (1 ± 0.20, preferably 1 ± 0.10, most preferably 1 ± 0.05); c = (t * 0.14) * (1 ± 0.20, preferably 1 ± 0.10, most preferably 1 ± 0.05); and d = (t * 0.14) * (1 ± 0.20, preferably 1 ± 0.10, most preferably 1 ± 0.05), a method in which t is a natural integer between 4 and 24, preferably between 8 and 21, such that between 12 and 15.

[0057] 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, most preferably between 40°C and 80°C, in particular to promote accelerated perforation of the adsorbent solid.

[0058] 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.

[0059] According to one or more embodiments, the injection point of the feed (F) in column or columns Ci is fed with between 2% and 99% of extract E (or a stream obtained by concentration and / or purification of said extract). Preferably, between 30% by weight and 80% by weight of extract E (or a stream obtained by concentration and / or purification of said extract) is fed to the injection point of the feed (F) in column or columns Ci. Preferably, the injection point of the feed (F) is fed with between 35% and 70%, preferably between 40% and 60%, such as substantially between 45% and 55%, of extract E, for example as obtained directly from the column outlet.

[0060] According to one or more embodiments, the cycle duration is at least 20 minutes, preferably at least 40 minutes, such that it is between 1 and 10 hours. Preferably, the cycle duration used is between 2 and 8 hours. The cycle duration corresponds to the switching period ST (the period between two successive switching of feeds / extractions) multiplied by the total number of injection / withdrawal points, such as the total number of columns Ci used (see example in Figure 1) or of adsorbent solid beds Ai used (see example in Figure 2). According to one or more embodiments, the average recycling rate (i.e., the ratio of the average recycling flow rate (average of the zone flow rates weighted by the number of columns or adsorbent solid beds per zone) to the feed flow rate) is between 2 and 12, preferably between 3 and 9, and most preferably between 5 and 8.

[0061] According to one or more embodiments, the ratio of the volumetric flow rate of the desorbent to the volumetric flow rate of the filler is less than 1, preferably less than 0.5, preferably less than 0.2, most preferably less than 0.1. According to one or more embodiments, the ratio of the volumetric flow rate of the desorbent to the volumetric flow rate of the filler is between 0.01 and 1.0, preferably between 0.02 and 0.5, most preferably between 0.06 and 0.1.

[0062] The simulated moving bed lithium adsorption extraction device comprises the following elements: at least one column (Ci) adapted to be fed with at least one charge comprising lithium and a desorbent, and to be withdrawn of at least one extract and at least one raffinate from the column (Ci), the at least one column (Ci) comprising an adsorbent solid, the at least one column (Ci) being interconnected in a closed loop, the feed and withdrawal points of the at least one column (Ci) being shifted over time by a value corresponding to a predetermined quantity of adsorbent solid with a permutation period and determining the plurality of zones I, II, III and IV as defined above, the device comprising a conduit adapted to recycle a portion of the extract to feed the at least one column.

[0063] According to one or more embodiments, the supply and withdrawal points of at least one column (Ci) are offset synchronously.

[0064] According to one or more embodiments, the feed and withdrawal points of at least one column (Ci) are shifted asynchronously. In this case, the cycle time refers to the time it takes for the injection and collection points to be sequenced until they return to their initial positions in the device. The amount of adsorbent solid contained in each of zones I, II, III, and IV, as defined above, is then calculated as the average amount of adsorbent solid contained in each zone over the cycle time. Similarly, the number of beds in each of zones I, II, III, and IV, as defined above, is calculated as the average number of adsorbent beds contained in each zone over the cycle time; this value may be a non-integer.According to one or more embodiments, the charge comprises and preferably consists of a (saline) solution containing lithium and which may or may not be saturated with salts, such as a brine.

[0065] 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.

[0066] The said charge can be any natural saline solution, concentrated or obtained from a lithium extraction or processing method. For example, the 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.

[0067] In one or more embodiments, the charge comprises at least 0.05 g / L by weight of lithium element, preferably in the form of LiCl, relative to the total weight of the charge. In 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, relative to the total weight of the charge.

[0068] In one or more embodiments, the desorbent is selected from the group consisting of water, lithium water, brine, and preferably water. In one or more embodiments, the desorbent comprises between 0 g / L and 1 g / L of lithium, preferably in the form of LiCl, relative to the total weight of the desorbent. In one or more embodiments, the desorbent comprises less than 0.05 g / L of lithium, preferably less than 0.01 g / L of lithium, relative to the total weight of the desorbent.

[0069] In one or more embodiments, the adsorbent solid comprises at least one lithiased aluminum oxyhydroxide Al₂O(OH)₃ and / or at least one lithiased aluminum hydroxide Al₂O(OH)₃. In one or more embodiments, the at least one lithiased aluminum oxyhydroxide Al₂O(OH)₃ comprises lithiased boehmite. In one or more embodiments, the at least one lithiased aluminum oxyhydroxide Al₂O(OH)₃ comprises at least 60% by weight, preferably at least 80% by weight, of lithiased boehmite, relative to the total weight of the at least one lithiased aluminum oxyhydroxide Al₂O(OH)₃. In one or more embodiments, the at least one lithiased aluminum oxyhydroxide Al₂O(OH)₃ consists of lithiased boehmite. According to one or more embodiments, at least one lithium aluminum hydroxide Al(OH)3 comprises lithium bayerite.In one or more embodiments, the at least one lithium-containing aluminum hydroxide Al(OH)3 comprises at least 60% by weight, preferably at least 80% by weight, of lithium-containing bayerite, relative to the total weight of the at least one lithium-containing aluminum hydroxide Al(OH)3. In one or more embodiments, the at least one lithium-containing aluminum hydroxide Al(OH)3 consists of lithium-containing bayerite.

[0070] In one or more embodiments, the adsorbent solid 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. In 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.

[0071] 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.

[0072] According to one or more embodiments, the adsorbent solid has a specific surface area characterized by nitrogen adsorption according to the BET method, between 1 m 2 / g and 30 m 2 / g, preferably between 1 m 2 / g and 20 m 2 / g.

[0073] In 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. In 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. In one or more embodiments, the adsorbent solid is in the form of extrudates with a diameter of between 0.15 mm and 5 mm, preferably between 0.2 mm and 3 mm, and more preferably between 0.5 mm and 1.0 mm.

[0074] 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 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.

[0075] Examples

[0076] The following examples allow comparison of a simulated countercurrent chromatography separation with extract E recycled in the load F (example 1 according to the invention), without extract E recycled (reference example 2) and with 20% recycled in the middle of zone 2 (reference example 3):

[0077] The process in examples 1 to 3 is applied for the purification and separation of a lithium brine with the following composition:

[0078] 0.4 g / L of lithium element;

[0079] 110 g / L as elemental chlorine;

[0080] 70 g / L as elemental sodium.

[0081] The solid adsorbent used for the separation is a lithia-treated bayerite.

[0082] The process uses a column Ci comprising 21 beds of solid adsorbent Ai distributed as follows:

[0083] 9 beds in zone 1;

[0084] 6 beds in zone 2; In the case of example 3, the recycled extract is injected in the middle of zone 2, i.e. 3 beds below the extract withdrawal and 3 beds above the feed injection.

[0085] 3 beds in zone 3;

[0086] 3 beds in zone 4.

[0087] Each column is 0.9 m long.

[0088] The separation takes place at 20°C. The desorbent is water that does not contain lithium.

[0089] The desorbent / feed flow rate ratio is 0.08. The surface velocity in zone 3 is 0.5 cm / s. The cycle time is 7 hours. Table 1 compares the performance of the LMS process with extract E recycled in the feed (Example 1 according to the invention) to an LMS process without extract E recycled (reference Example 2). The LMS process with extract E recycled in the feed (Example 1 according to the invention) is carried out with an extract recycle rate of 50%, meaning that 50% of the volumetric flow rate of extract E is returned to the feed F of the LMS process.

[0090] Lithium purity is defined as the ratio of the mass of lithium to the cumulative mass of sodium.

[0091] The process according to the invention makes it possible to significantly increase the lithium content of the extract while ensuring very high purity. This increase in lithium concentration reduces the amount of water to be evaporated per mass of lithium produced by 28%.

Claims

1. Demands 1. A simulated moving bed lithium adsorption extraction process comprising the following step: at least one column (Ci) is fed with at least one charge (F) comprising lithium and a desorbent (D), and at least one extract (E) and at least one raffinate (R) are withdrawn from the column (Ci), the at least one column (Ci) comprising a sorbent solid, the at least one column (Ci) being interconnected in a closed loop, the feed and withdrawal points of the at least one column (Ci) being shifted over time by a value corresponding to a predetermined quantity of absorbent solid with a permutation period and determining a plurality of operating zones of the column (Ci), and in particular the following principal zones designated by definition by a number: a lithium desorption zone I comprising a desorbent injection point (D) and an extract withdrawal point (E);a zone II for the desorption of alkali metals other than lithium and / or alkaline earth metals located between the point of withdrawal of the extract (E) and a point of injection of the feed (F) including lithium; a zone III for the adsorption of lithium located between the point of injection of the feed (F) and a point of withdrawal of the raffinate (R); and a zone IV is located between the point of withdrawal of the raffinate (R) and the point of injection of the desorbent (D), a process in which a part of the extract (E) is recycled to the feed (F).

2. A method according to claim 1, wherein at least one column (Ci) comprises a plurality of columns (Ci) or adsorbers interconnected in a closed loop, the supply and withdrawal points of the columns (Ci) or adsorbers being shifted over time by a value corresponding to one column (Ci) or one adsorber.

3. Method according to claim 1 or claim 2, wherein the plurality of columns (Ci) or adsorbers comprises at least 4 columns or adsorbers.

4. A method according to any one of the preceding claims, wherein the absorbent solid is distributed in zones I to IV according to so-called a / b / c / d type configurations, i.e., the distribution of the absorbent solid, relative to the total quantity of absorbent solid, is as follows: a is the quantity of absorbent solid in zone I; b is the quantity of absorbent solid in zone II; c is the quantity of absorbent solid in zone III; and d is the quantity of adsorbent solid in zone IV, process in which: a = 43% ± 9%; b = 29% ± 6%; c = 14% ± 3%; and d = 14% ± 3%.

5. Method according to claim 1, the at least one column (Ci) comprises a plurality of beds of solid adsorbent (Aj) interconnected in a closed loop and separated by trays (Pi), the feeding and withdrawal points in the trays (Pi) of the column (Ci) being shifted over time by a value corresponding to one bed of adsorbent.

6. Method according to claim 5, wherein at least one column (Ci) comprises between 4 and 24 beds of solid adsorbent (Ai).

7. A method according to claim 5 or claim 6, wherein the beds of solid adsorbent (Ai) are distributed in zones I to IV according to configurations of type a / b / c / d, that is to say that the distribution of the beds of solid adsorbent (Ai) is as follows: a is the number of beds in zone I; b is the number of beds in zone II; c is the number of beds in zone III; and d is the number of beds in zone IV, a method in which: a = (t * 0.43) * (1 ± 0.20); b = (t * 0.29) * (1 ± 0.20); c = (t * 0.14) * (1 ± 0.20); and d = (t * 0.14) * (1 ± 0.20), a method in which t is a natural number between 4 and 24.

8. A process according to any one of the preceding claims, wherein the adsorbent solid comprises at least one lithia aluminum oxyhydroxide Al₂O(OH)₂ and / or at least one lithia aluminum hydroxide Al₂O(OH)₂s.

9. A method according to any one of the preceding claims, wherein the adsorbent solid comprises lithium bayerite and / or lithium boehmite.

10. A method according to any one of the preceding claims, wherein the adsorbent solid comprises between 0.1 wt% and 5 wt% of lithium element, relative to the total wt% of the adsorbent solid.

11. A method according to any one of the preceding claims, wherein the adsorbent solid comprises a solid material of formula (LiCl) x .2Al(OH)3,nH2O, where n is between 0.01 and 10, and x is between 0.4 and 1.

12. A method according to any one of the preceding claims, wherein the charge (F) comprises at least 0.05 g / L weight of lithium element, relative to the total weight of the charge.

13. A process according to any one of the preceding claims, wherein the steps of the process are carried out at a temperature between 0°C and 160°C.

14. A method according to any one of the preceding claims, wherein the ratio of the volumetric flow rate of the desorbent (D) to the volumetric flow rate of the charge (F) is less than 1.

15. Simulated moving bed lithium adsorption extraction device comprising the following elements: at least one column (Ci) adapted to be fed with at least one charge (F) comprising lithium and a desorbant (D), and to be withdrawn of at least one extract (E) and at least one raffinate (R), the at least one column (Ci) comprising an adsorbent solid, the at least one column (Ci) being interconnected in a closed loop, the feeding and withdrawal points of the at least one column (Ci) being shifted over time by a value corresponding to a predetermined quantity of adsorbent solid with a permutation period and determining a plurality of column (Ci) operating zones, and in particular the following principal zones designated by definition by a number: a lithium desorption zone I comprising a desorbent injection point (D) and an extract withdrawal point (E);a zone II for the desorption of alkali metals other than lithium and / or alkaline earth metals comprising between the point of withdrawal of the extract (E) and a point of injection of the feed (C) comprising lithium; a zone III for the adsorption of lithium comprising between the point of injection of the feed (C) and a point of withdrawal of the raffinate (R); and a zone IV comprising between the point of withdrawal of the raffinate (R) and the point of injection of the desorbent (D), the device comprising a conduit adapted to recycle a portion of the extract (E) to feed the feed (C) to at least one column.

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