Method and device for extracting lithium by adsorption with upflow elution

Abstract

The invention relates to a method for extracting lithium by adsorption, the method comprising at least the following steps: at least one adsorption step in which at least one extraction column (C) is fed with at least one feed (F) and at least one raffinate (R) is withdrawn from the at least one extraction column (C); at least one elution step in which the at least one extraction column (C) is fed with at least one desorbent (D) and at least one extract (E) is withdrawn from the at least one extraction column (C), wherein the at least one extraction column (C) comprises at least one bed of adsorbent solid, and wherein the at least one adsorption step and the at least one elution step are carried out in opposite directions relative to one another through the extraction column (C); the invention also relates to an extraction device suitable for carrying out the extraction method.

Description

[0001] Method and apparatus for lithium adsorption extraction with upward flow elution

[0002] technical field

[0003] The present invention relates to the field of lithium adsorption extraction.

[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 an extraction column on which the lithium is captured, the latter then being fed with an eluent to desorb the desired lithium.

[0008] Several cycles are possible, and the choice of configuration and associated settings significantly impacts process performance. For example, at the 2017 SFGP congress, a cycle with two extraction columns in series during the adsorption phase and a single extraction column during elution was highlighted to improve lithium recovery. This cycle proposed performing adsorption and elution by passing through the bed in the same direction, in a downward flow pattern.

[0009] However, lithium adsorption extraction 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 that increases the concentration of lithium in the extract and reduces the energy consumption of the process.According to a first aspect, the aforementioned objects, as well as other advantages, are obtained by a lithium adsorption extraction process comprising at least the following step: at least one adsorption step in which at least one extraction column is fed with at least one charge and at least one raffinate is withdrawn from at least one extraction column; at least one elution step in which at least one extraction column is fed with at least one desorbent and at least one extract is withdrawn from at least one extraction column, process in which: at least one extraction column comprises at least one bed of adsorbent solid; and at least one adsorption step and at least one elution step are carried out in opposite directions to each other through the extraction column (opposite flow direction).

[0012] According to one or more embodiments, the extraction column is a vertical extraction column.

[0013] According to one or more embodiments, at least one adsorption step is carried out in downward current and at least one elution step is carried out in upward current.

[0014] According to one or more embodiments, the extraction process comprises several adsorption steps and / or several elution steps, all the adsorption steps and all the elution steps being (always) carried out in opposite directions, relative to each other.

[0015] According to one or more embodiments, the extraction process comprises the following steps: at least one extraction column is fed with the feed and a first raffinate is withdrawn from at least one extraction column; at least one extraction column is fed with the feed and a second raffinate is withdrawn from at least one extraction column; at least one extraction column is fed with the desorbent and a first extract is withdrawn from at least one extraction column; at least one extraction column is fed with the desorbent and a second extract is withdrawn from at least one extraction column.

[0016] According to one or more embodiments, the first raffinate is at least partially recycled as a desorbent. According to one or more embodiments, the first extract is at least partially recycled as a filler.

[0017] 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 (e.g. brine).

[0018] 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.

[0019] According to one or more embodiments, the desorbent is chosen from the group consisting of water, lithia water, brine, preferably water.

[0020] 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.

[0021] According to one or more embodiments, the adsorbent solid comprises at least one lithiaated aluminium oxyhydroxide Al0(OH) and / or at least one lithiated aluminium hydroxide Al(OH)3.

[0022] According to one or more embodiments, the adsorbent solid comprises and preferably consists of lithium bayerite and / or lithium boehmite.

[0023] 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.

[0024] 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.

[0025] According to one or more embodiments, the process steps 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 most preferably between 5°C and 100°C, particularly preferably between 15°C and 80°C, and most preferably between 40°C and 80°C, notably to promote accelerated penetration of the adsorbent solid. According to one or more embodiments, 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. According to 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 most preferably between 0.1 MPa and 2.5 MPa.

[0026] 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.

[0027] According to one or more embodiments, the volume eluted during all the elution steps divided by the volume eluted during all the adsorption steps is between 0.01 and 2, preferably between 0.05 and 0.5.

[0028] According to a second aspect, the aforementioned objects, as well as other advantages, are obtained by a lithium adsorption extraction device comprising at least one extraction column comprising at least one bed of solid adsorbent, the extraction column comprising inlet points and outlet points fitted with valves adapted to: supply at least one extraction column with at least one charge and withdraw at least one raffinate from at least one extraction column; supply at least one extraction column with at least one desorbent and withdraw at least one extract from at least one extraction column, all the charge and raffinate flows and all the desorbent and extract flows flowing in opposite directions to each other through the extraction column (opposite flow direction).

[0029] Other features and advantages of the invention, according to the aforementioned aspects, will become apparent from the following description and non-limiting examples of implementation, with reference to the figures attached and described below.

[0030] List of figures

[0031] Figure 1 represents a lithium adsorption extraction process according to the prior art (A) and according to the invention (B) illustrating in particular the sending of the desorbent D into the extraction column against the current of the charge F.

[0032] Figure 2 shows a lithium adsorption extraction process according to the invention, illustrating in particular a 4-step cycle using an extraction column. Description of embodiments

[0033] 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.

[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%.

[0035] The present invention relates to a lithium adsorption extraction process employing at least one adsorption step and at least one elution (or desorption) step in opposite directions (counter-current adsorption and elution flows). Advantageously, when the feed flow during the adsorption step and the eluent (or desorbent) flow during the elution (or desorption) step are in opposite directions (e.g., up vs. down for a vertical extraction column; right vs. left for a horizontal extraction column), the extraction process according to the invention makes it possible to increase the lithium concentration in the extract, thereby reducing energy consumption during the water evaporation step downstream of the extraction process.

[0036] Preferably, the extraction column is a vertical extraction column.

[0037] Preferably, the adsorption step is carried out with a downward flow and the elution step with an upward flow. Advantageously, operation with downward flow adsorption and upward flow elution allows for a lower flow rate for the adsorption step, thus reducing the risk of fluidization during the adsorption step.

[0038] Figure 1 illustrates the principle of the invention with respect to the prior art. The first step of the process according to the prior art (A) and the invention (B) is an adsorption step, during which a charge F comprising lithium is injected at the top of a column C comprising an adsorbent bed. As the charge F passes through the adsorbent bed, the lithium progressively saturates the adsorbent bed. The output stream from this step constitutes the raffinate R, which is low in lithium (relative to the charge) and can be sent, for example, to the source reservoir (e.g., salt flats, sea, etc.).

[0039] The second step consists of eluting the previously adsorbed lithium. In prior art processes (A), the desorbent D (eluent) flows through column C in the same direction as during the adsorption step and displaces the lithium for recovery in extract E. In the process according to the invention (B), the desorbent D is sent in the opposite direction to the first step (i.e., relative to the direction of flow of charge F) to recover extract E at the top of column C. Once the second step is completed, the first step can be repeated.

[0040] According to one or more embodiments, the extraction process comprises several adsorption steps and / or several elution steps, in which all the adsorption steps and all the elution steps are (always) carried out in opposite directions. For example, Figure 2 shows a 4-step cycle using a single column. The 4 steps can be carried out on one or more columns, consecutively (e.g., on one column) or simultaneously (on several columns). The first two steps, 1 and 2, correspond to the adsorption of the lithium contained in the feedstock F. The first raffinate R1 from step 1 can be partially or completely recycled as a desorbent D for elution steps. The second raffinate R2 constitutes the lithium-depleted output stream of the process.

[0041] Steps 3 and 4 are the elution steps where lithium is desorbed by displacement with desorbent D. The first extract E1 from step 3 can be partially or completely recycled as feedstock F for adsorption phases. The second extract E2 from step 4 constitutes the lithium-enriched output stream, the product of interest. The cycle then restarts at step 1.

[0042] 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.

[0043] According to one or more embodiments, the charge comprises at least one of the following elements denoted B: Na, K, Rb, Cs, Mg, Ca, Sr, Ba, F, Cl, Br, I, SO4, CO3, NO3, B and HCO3.

[0044] The feedstock 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.

[0045] According to one or more embodiments, the charge comprises at least 0.05 g / L of lithium element, preferably in the form of LiCl, relative to the total weight of the charge. 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, relative to the total weight of the charge.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] In one or more embodiments, the at least one lithiased aluminum hydroxide Al(OH)3 comprises lithiased bayerite. In one or more embodiments, the at least one lithiased aluminum hydroxide Al(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 Al(OH)a. In one or more embodiments, the at least one lithiased aluminum hydroxide Al(OH)a consists of lithiased bayerite.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] According to one or more embodiments, the volume eluted during all the elution steps divided by the volume eluted during all the adsorption steps is between 0.01 and 2, preferably between 0.05 and 0.5.

[0059] According to one or more embodiments, the desorbent passes through the extraction column (C) with a surface velocity of between 0.1 and 10 m / h, preferably between 2 and 7 m / h.

[0060] Examples

[0061] The process according to the invention is applied for the purification and separation of a lithium brine of the following composition:

[0062] 0.2 g / L of lithium element;

[0063] 60 g / L as elemental chlorine;

[0064] 30 g / L as elemental sodium.

[0065] The adsorbent used for separation is lithium-containing bayerite. The process temperature is 60°C. The desorbent is water containing 0.12 g / L of lithium. The volume eluted by adsorption corresponds to 13.5 bed volumes. The volume eluted by elution corresponds to 4.5 bed volumes. In process A (reference), adsorption and elution are performed in downward flow.

[0066] In process B (the invention), adsorption is carried out in a downward flow mode and elution is carried out in an upward flow mode. 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.

[0067] Table 1

[0068] The process according to the invention makes it possible to increase both the lithium yield and the lithium extract concentration.

Claims

Demands 1. Lithium adsorption extraction process comprising at least the following steps: at least one adsorption step in which at least one extraction column (C) is fed with at least one charge (F) and at least one raffinate (R) is withdrawn from at least one extraction column (C); at least one elution step in which at least one extraction column (C) is fed with at least one desorbent (D) and at least one extract (E) is withdrawn from at least one extraction column (C), process in which: at least one extraction column (C) comprises at least one bed of adsorbent solid; and at least one adsorption step and at least one elution step are carried out in opposite directions, relative to each other, through the extraction column (C).

2. Method according to claim 1, wherein the extraction column (C) is a vertical extraction column.

3. A method according to claim 2, wherein at least one adsorption step is carried out in a downward current and at least one elution step is carried out in an upward current.

4. A process according to any one of the preceding claims, comprising several adsorption steps and / or several elution steps, all the adsorption steps and all the elution steps being carried out in opposite directions to each other.

5. A method according to any one of the preceding claims, comprising the following steps: feeding at least one extraction column (C) with the charge (F) and withdrawing a first raffinate (R1) from at least one extraction column (C); feeding at least one extraction column (C) with the charge (F) and withdrawing a second raffinate (R2) from at least one extraction column (C); feeding at least one extraction column (C) with the desorbent (D) and withdrawing a first extract (E1) from at least one extraction column (C); feeding at least one extraction column (C) with the desorbent (D) and withdrawing a second extract (E2) from at least one extraction column (C).

6. A process according to claim 5, wherein the first raffinate (R1) is at least partially recycled as a desorbent (D).

7. A process according to claim 5 or claim 6, wherein the first extract (E1) is at least partially recycled as a feed (F).

8. A method according to any one of the preceding claims, wherein the charge (F) comprises and preferably consists of a (saline) solution containing lithium and which may or may not be saturated with salts (e.g. brine).

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

10. A process according to any one of the preceding claims, wherein the adsorbent solid comprises at least one lithiaated aluminium oxyhydroxide Al0(OH) and / or at least one lithiated aluminium hydroxide Al(OH)3.

11. A process according to any one of the preceding claims, wherein at least one adsorption step and at least one elution step are carried out at a temperature between 0°C and 160°C.

12. A method according to any one of the preceding claims, wherein at least one adsorption step and at least one elution step are carried out at a pressure in the beds of solid adsorbent between 0.09 MPa and 5 MPa.

13. A method according to any one of the preceding claims, wherein 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.

14. A method according to any one of the preceding claims, wherein the volume eluted during all the elution steps divided by the volume eluted during all the adsorption steps is between 0.01 and 2, preferably between 0.05 and 0.

5.

15. Lithium adsorption extraction device comprising at least one extraction column (C) comprising a bed of solid adsorbent, the extraction column (C) comprising inlet points and outlet points fitted with valves adapted to: supply at least one extraction column (C) with at least one charge (F) and withdraw at least one raffinate (R) from at least one extraction column (C); supply at least one extraction column (C) with at least one desorbent (D) and withdraw at least one extract (E) from at least one extraction column (C), the whole of the charge (F) and raffinate (R) flows and the whole of the desorbent (D) and extract (E) flows flowing in opposite directions, relative to each other, through the extraction column (C).

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