PROCESS FOR PREPARING AN ADSORBENT MATERIAL IN THE ABSENCE OF BINDER COMPRISING A HYDROTHERMAL TREATMENT STEP AND PROCESS FOR EXTRACTING LITHIUM FROM SALINE USING SAID MATERIAL

Abstract

A method for preparing a crystallized solid material of formula LiCl.2Al(OH).sub.3.nH.sub.2O with n being comprised between 0.01 and 10, includes mixing in an aqueous medium, at least one source of alumina and at least one source of lithium in order to obtain a suspension, filtering the resulting suspension obtained for obtaining a slurry, followed by drying the obtained slurry and shaping the dried slurry after the drying to obtain a shaped solid material. The shaping is carried out in absence of a binder followed by drying and a hydrothermal treatment to obtain the shaped crystallized solid material of formula LiCl.2Al(OH).sub.3.nH.sub.2O. A method for extracting lithium from saline solutions uses the thereby prepared material.

Claims

1. A method for preparing a crystallized solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 10, said method comprising at least the following steps: a) mixing, in an aqueous medium, at least one source of alumina and at least one source of lithium thereby obtaining a suspension, b) filtering the suspension obtained in a) thereby obtaining a slurry, c) drying the slurry obtained at the end of b), at a temperature comprised between 20 and 80 C., d) shaping said dried slurry, directly after said drying of c), said shaping d) being carried out in the absence of any binder, e) drying the shaped material obtained at the end of d) at a temperature comprised between 20 and 200 C., f) hydrothermally treating the shaped and dried material obtained at the end of e).

2. The method according to claim 1, wherein the source of alumina is aluminium trihydroxide Al(OH).sub.3.

3. The method according to claim 1, wherein the lithium source is selected from the group consisting of lithium chloride (LiCl), lithium hydroxide (LiOH), lithium nitrate (LiNO.sub.3), lithium sulfate (Li.sub.2SO.sub.4), lithium carbonate (Li.sub.2CO.sub.3), and any mixture thereof.

4. The method according to claim 3 wherein the lithium source is lithium chloride (LiCl).

5. The method according to claim 1, wherein said mixing a) is performed at a temperature comprised between 40 and 120 C. for a period comprised between 1 hour and 10 hours.

6. The method according to claim 1 wherein said dried slurry does not undergo any intermediate steps between said drying c) and said shaping d).

7. The method according to claim 1, wherein said drying e) is performed at a temperature comprised between 20 and 100 C. for a period comprised between 1 hour and 18 hours.

8. The method according to claim 1, wherein said f) is performed at a temperature comprised between 80 and 150 C.

9. The method according to claim 1, wherein said f) is performed in the presence of a humid atmosphere having a water content comprised between 80 and 100% by weight.

10. A crystallized solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 10, obtainable according to a method according to claim 1.

11. A method for extracting lithium from saline solutions using a solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n comprised between 0.01 and 10, prepared according to the method as defined according to claim 1.

12. The extraction method according to claim 11, wherein said lithium extraction method comprises at least the following steps: activating said crystallized solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O, loading said activated material by adsorption by passing said saline solution over said activated material thereby obtaining a loaded material, washing the saline solution impregnating said loaded material by passing a washing solution over said loaded material thereby obtaining a washed material, desorption of lithium by passing water or an aqueous solution of a lithium salt over said washed material thereby obtaining an eluate comprising at least lithium.

13. The extraction method according to claim 12, wherein said activation is carried out by the upward or downward passing of water or of a lithium chloride (LiCl) solution having a concentration comprised between 0.001 mol/L and 0.1 mol/L.

14. The extraction method according to claim 12, wherein said activation is carried out at a temperature comprised between 0 C. and 90 C., and at a flow rate comprised between 0.1 BV/h and 30 BV/h, wherein BV/h means the volume occupied by the bed of the solid in a column, per hour.

15. The extraction method according to claim 12, wherein said loading is carried out at a temperature comprised between 0 C. and 90 C., and at a flow rate comprised between 0.1 BV/h and 30 BV/h, wherein BV/h means the volume occupied by the bed of the solid in a column, per hour.

16. The extraction method according to claim 12, wherein said washing solution is water or an aqueous solution of sodium chloride (NaCl), optionally comprising lithium chloride (LiCl).

17. The extraction method according to claim 12, wherein said washing is carried out at a temperature comprised between 0 C. and 90 C., and at a flow rate comprised between 0.1 BV/h and 30 BV/h, wherein BV/h means the volume occupied by the bed of the solid in a column, per hour.

18. The extraction method according to claim 12, wherein said desorption is carried out by upward or downward passing of water or of a solution of lithium chloride (LiCl) containing from 0.001 mol/L to 2 mol/L of LiCl.

19. The extraction method according to claim 12, wherein said desorption is carried out at a temperature comprised between 0 C. and 90 C., and at a flow rate comprised between 0.1 BV/h and 30 BV/h, wherein BV/h means the volume occupied by the bed of the solid in a column, per hour.

20. A lithium extraction device characterizing that it comprises a unit comprising at least one column, said column comprising at least one pattern comprising the crystallized solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 10, shaped obtainable according to a method according to claim 1.

Description

DESCRIPTION OF THE FIGURES

[0142] FIG. 1 illustrates the x-ray diffraction diagram of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O obtained as extrudates in accordance with Example 5 according to the invention.

[0143] The invention is illustrated by the following examples which by no means have any limitation.

EXAMPLES

Example 1: (Comparative)

[0144] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 1, is prepared according a synthesis method not compliant with the invention in that the step for shaping the obtained slurry is carried out according to the conventional acid/basic kneading extrusion technique, a technique applied according to the knowledge of one skilled in the art, and in that the method does not comprise any final hydrothermal treatment step.

[0145] 1/ Synthesis of Al(OH).sub.3

[0146] In a beaker cooled with an ice bath, a solution containing 326 ml of permuted water and 135.6 g of aluminium chloride hexahydrate (AlCl.sub.3) is prepared. Next, under magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are slowly added. This cake is suspended in a 3 L beaker with 320 ml of water.

[0147] 2/ Addition of Lithium Chloride LiCl.

[0148] A solution is prepared containing 78.5 g of lithium chloride LiCl provided by Prolabo and 1,326 ml of water which is added to the repulped cake. This reaction medium is stirred and heated to 80 C. for 2 h.

[0149] Filtration and drying in an oven at 80 C. for 8 h follow the first 2 steps.

[0150] The obtained dried slurry is then shaped according to the conventional technique of acid/basic kneading-extrusion. The dried slurry is introduced into a kneader of the Brabender type. The water acidified with nitric acid is added within 4 minutes, with kneading at 20 revolutions/min. The acid kneading is continued for 10 minutes. A neutralization step is then carried out by adding an ammonia solution in the kneader and kneading is continued for 3 minutes.

[0151] The kneading is carried out with a total acid level, expressed relatively to the dried slurry of 2%, and a neutralization level of 20%.

[0152] At the end of the kneading, no cohesive slurry was able to be obtained.

[0153] The obtained wet solid is shaped by means of a piston extruder (MTS), equipped with a cylindrical die with a diameter of 1 mm.

[0154] No intact extrudate was able to be obtained.

[0155] The obtained rings are very friable and do not have any cohesion in brine.

Example 2 (Comparative)

[0156] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 1, is prepared according to a synthesis method non-compliant with the invention in that the step for shaping the obtained slurry is carried out by kneadingextrusion in the presence of an inorganic binder from the family of hydraulic binders added during the kneading phase and in that the method does not comprise any final hydrothermal treatment step.

[0157] 37.7 g of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 1 are obtained according to the method described in Example 1 with the difference that the shaping step is carried out by kneadingextrusion in the presence of an inorganic binder.

[0158] The dried slurry obtained at the end of the first drying of Example 1 is introduced into a kneader of the Brabender type in the presence of 21.8 g of water and in the presence of 4.6 g of Dyckerhoff cement as a hydraulic binder and is simply kneaded.

[0159] The obtained slurry is shaped by means of a piston extruder (MTS), equipped with a cylindrical die with diameter of 1 mm.

[0160] The obtained extrudate at the end of the shaping step are then dried in an oven at 40 C. for 12 h.

[0161] The extrudates obtained at the end of the shaping step are also dried in a weathering oven at 25 C. for 48 h under air saturated with 98% of water.

[0162] Both drying methods led to the same result: the obtained extrudates are friable and exhibit many cracks.

Example 3: (Comparative)

[0163] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n being comprised between 0.01 and 1, is prepared according to a synthesis method not compliant with the invention in that the step for calcination of the extrudates is carried out according to the knowledge of one skilled in the art at a temperature above 500 C. and in that the method does not comprise any final hydrothermal treatment step.

[0164] 1/ Synthesis of Al(OH).sub.3

[0165] In a beaker cooled by an ice bath, a solution containing 326 ml of permuted water and 135.6 g of aluminium chloride hexahydrate AlCl.sub.3 is prepared. Next with magnetic stirring, 67.5 g of sodium hydroxide NaOH are added slowly. This cake is suspended in a 3 L beaker with 320 ml of water.

[0166] 2/ Addition of Lithium Chloride LiCl.

[0167] A solution is prepared containing 78.5 g of lithium chloride LiCl provided by Prolabo and 1,326 ml of water which is added to the repulped cake. This reaction medium is stirred and heated to 80 C. for 2 h.

[0168] Filtration and drying in an oven at 40 C. for 8 h follow the first 2 steps.

[0169] The obtained slurry is directly shaped by means of a piston extruder (MTS), equipped with a cylindrical die with a diameter of 0.8 mm, without any prior kneading step. Extrudates exhibiting a correct aspect are obtained. These extrudates are calcined at 500 C. for 4 h.

[0170] The x-ray diffraction diagram of the extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O obtained exhibits an undesired phase of the Li.sub.0.5Al.sub.2O.sub.4 type which is a product from the decomposition of the LiCl.2Al(OH).sub.3,nH.sub.2O phase.

Example 4 (Comparative)

[0171] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 according to a synthesis method is prepared, in which the step for shaping the obtained slurry is directly carried out after the drying step, without any prior kneading step but not compliant with the invention in that the method does not comprise any final hydrothermal treatment step.

[0172] 1/ Synthesis of Al(OH).sub.3

[0173] In a beaker cooled by an ice bath, a solution containing 326 ml of permuted water and 135.6 g of aluminium chloride hexahydrate (AlCl.sub.3) is prepared. Next under magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are slowly added. This cake is suspended in a 3 L beaker with 320 ml of water.

[0174] 2/ Addition of the Lithium Chloride LiCl.

[0175] A solution is prepared containing 78.5 g of lithium chloride LiCl provided by Prolabo and 1,326 ml of water which is added to the repulped cake. This reaction medium is stirred and heated to 80 C. for 2 h.

[0176] Filtration and then drying in an oven at 40 C. for 8 h follow the first 2 steps.

[0177] The obtained slurry is directly shaped by means of a piston extruder (MTS), without any intermediate kneading step of said slurry. The piston extruder is equipped with a cylindrical die with a diameter of 0.8 mm. These extrudates are then dried at 40 C. for 12 h in an oven.

[0178] The obtained extrudates do not undergo any hydrothermal treatment step in an autoclave according to the invention.

[0179] Extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 having good cohesion and a correct aspect are obtained. A phase LiCl.2Al(OH).sub.3,nH.sub.2O is detected on the x-ray diffraction diagram of the extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25.

[0180] The obtained extrudates are also characterized by the following measurements:

[0181] Elementary analysis shows good Li/Al/Cl stoichiometry corresponding to the composition of a structure LiCl.2Al(OH).sub.3,nH.sub.2O.

[0182] Al=21.2% by mass; Li=4.2% by mass; Cl=19% by mass.

[0183] The obtained extrudates have a specific surface area: S.sub.BET=3 m.sup.2/g.

Example 5 (According to the Invention)

[0184] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 is prepared according to a synthesis method according to the invention, wherein the step for shaping the obtained slurry is directly carried after the drying step, without any prior kneading step and wherein the obtained extrudates are subject to a final hydrothermal treatment step in the presence of water.

[0185] The extrudates are prepared like in Example 4 as far as the drying step in an oven at 40 C. for 12 h.

[0186] The obtained extrudates are then subject to a hydrothermal treatment step in an autoclave comprising water. 10 g of extrudates are placed in a basket placed in an autoclave of 500 ml. In the bottom of the autoclave are put 20 g of distilled water. The extrudates are not in contact with the liquid at the bottom of the autoclave.

[0187] The hydrothermal treatment is performed at a temperature of 100 C. for 6 h in an atmosphere saturated with water.

[0188] Extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 having good cohesion and a correct aspect are obtained. A phase LiCl.2Al(OH).sub.3,nH.sub.2O is detected on the x-ray diffraction diagram of the extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 of FIG. 1.

[0189] The obtained extrudates are also characterized by the following measurements:

[0190] Elementary analysis shows good Li/Al/Cl stoichiometry corresponding to the composition of a structure LiCl.2Al(OH).sub.3,nH.sub.2O.

[0191] Al=21.2% by mass; Li=4.2% by mass; Cl=19% by mass.

[0192] The obtained extrudates have a specific surface area: S.sub.BET=3 m.sup.2/g.

Example 6 (According to the Invention)

[0193] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 is prepared according to a synthesis method according to the invention, wherein the step for shaping the obtained slurry is directly carried out after the drying step, without any prior kneading step and wherein the obtained extrudates are subject to a final hydrothermal treatment step in the presence of a mixture of water and acid.

[0194] The extrudates are prepared like in Example 4 with the difference that the obtained extrudates are then subject to a hydrothermal treatment step in an autoclave comprising in its bottom a mixture of water and nitric acid in order to obtain a pH equal to 3. 10 g of extrudates are placed in a basket placed in a 500 ml autoclave. 20 g of acidified water are put in the bottom of the autoclave. The extrudates are not in contact with the liquid at the bottom of the autoclave.

[0195] The hydrothermal treatment is performed at a temperature of 100 C. for 8 h under an atmosphere saturated with water.

[0196] Extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 having good cohesion and a correct aspect are obtained. A phase LiCl.2Al(OH).sub.3,nH.sub.2O is detected on the x-ray diffraction diagram of the extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25.

[0197] The obtained extrudates are also characterized by the following measurements:

[0198] Elementary analysis shows good Li/Al/Cl stoichiometry corresponding to the composition of a structure LiCl.2Al(OH).sub.3,nH.sub.2O.

[0199] Al=21.2% by mass; Li=4.2% by mass; Cl=19% by mass.

[0200] The obtained extrudates have a specific surface area: S.sub.BET=3 m.sup.2/g.

Example 7 (According to the Invention)

[0201] A solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 is prepared according to a synthesis method according to the invention, wherein the step for shaping the obtained slurry is directly carried out after the drying step, without any prior kneading step and wherein the obtained extrudates are subject to a final hydrothermal treatment step in the presence of a mixture of water and of a base.

[0202] The extrudates are prepared like in Example 4 with the difference that the obtained extrudates are then subject to a hydrothermal treatment step in an autoclave comprising in its bottom a mixture of water and of soda in order to obtain a pH equal to 11. 10 g of extrudates are placed in a basket placed in a 500 ml autoclave. 20 g of basic water are placed in the bottom of the autoclave. The extrudates are not in contact with the liquid at the bottom of the autoclave.

[0203] The hydrothermal treatment is performed at a temperature of 100 C. for 6 h under an atmosphere saturated with water.

[0204] Extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25 having good cohesion and a correct aspect are obtained.

[0205] A phase LiCl.2Al(OH).sub.3,nH.sub.2O is detected on the x-ray diffraction diagram of the extrudates of the solid material of formula LiCl.2Al(OH).sub.3,nH.sub.2O with n=0.25.

[0206] The obtained extrudates are also characterized by the following measurements:

[0207] Elementary analysis shows good Li/Al/Cl stoichiometry corresponding to the composition of a structure LiCl.2Al(OH).sub.3,nH.sub.2O.

[0208] Al=21.2% by mass; Li=4.2% by mass; Cl=19% by mass.

[0209] The obtained extrudates have a specific surface area: S.sub.BET=3 m.sup.2/g.

Example 8

Cohesion and Mechanical Strength Test by Accelerated Ageing on a Stirring Table

[0210] The mechanical strength of the extrudates may be tested via an accelerated ageing procedure on a stirring table in two different media: [0211] 5 g of shaped solid material and 25 ml of natural brine are placed in a cylindrical container with a capacity of 60 ml. This container is attached to the stirring table during the whole period of the test. [0212] The composition of the natural brine used during this test is given in Table 1.

TABLE-US-00002 TABLE 1 composition of the natural brine used for the mechanical strength test Na K Li Mg Ca B SO.sub.4 Sr Cl Concen- 4.4 0.24 0.068 0.086 0.040 0.031 0.035 0.001 4.89 tration (mol/L) [0213] 5 g of shaped solid material and 25 ml of water are placed in a cylindrical container with a capacity of 60 ml. This container is attached to the stirring table for the whole period of the test.

[0214] The stirring table performs a horizontal unidirectional movement with an amplitude of 4 cm at a speed of 190 movements per minute. The shaped solids are then stirred for a total period of 168 h.

[0215] At the end of these 168 h, the shaped solid mixture-brine is sifted by means of a grid of 315 m. Next the shaped solids remaining on the sieve are washed with the medium used during the stirring (brine for which the composition is indicated in table 1 or water). The thereby obtained liquid fraction, containing fine solid particles (diameter of less than 315 m) in suspension, is filtered by means of a Buchner equipped with a paper filter for which the pores have a dimension of 0.45 m. The cake formed by the agglomeration of the fine particles is washed with demineralized water.

[0216] The thereby obtained solid residue is dried in an oven at 50 C. until stabilization of the mass.

[0217] The ratio of the solid residue mass over the mass of the initial shaped mass of solids is then calculated, giving access to a destruction percentage of the shaped solids.

[0218] The destruction percentage of the shaped solids gives the possibility of appreciating the cohesion of the solids as well as their mechanical strength. Good cohesion is notably obtained for solids for which the destruction percentage is less than 60%, and preferably less than 50%. Improved mechanical strength and resistance is notably obtained for solids for which the destruction percentage is less than 40%, and preferably less than 30%.

[0219] The mechanical strength of the extrudates obtained according to Examples 1 to 6 is tested in contact with a solution of natural brine and of water.

[0220] The various results are summarized in Table 2.

TABLE-US-00003 TABLE 2 applied shaping procedure and aspect of the corresponding extrudates Examples 1 (non-compliant) 2 (non-compliant) 3 (non-compliant) 4 (comparative) Shaping step (MEF) Acid and basic Kneading with a Direct extrusion Direct kneading + cement binder + extrusion extrusion without extrusion any binder Aspect of the Rings which Many cracks, Extrudates Visually intact extrudates in contact rapidly disintegrate extrudates which without any extrudates with brine become a powder apparent defects Hydrothermal no no no no treatment XRD phase Li.sub.0.5Al.sub.2O.sub.4 LiCl2Al(OH).sub.3, nH.sub.2O Brine cohesion test, >60% >60% 40% destruction % Water cohesion test, >60% >60% 50% destruction % Examples 5 (compliant) 6 (compliant) 7 (compliant) Shaping step (MEF) direct extrusion direct extrusion direct extrusion Aspect of the Visually intact Visually intact Visually intact extrudates in contact extrudates extrudates extrudates with brine Hydrothermal Autoclave Autoclave Autoclave treatment Water Water + acid Water + base XRD phase LiCl2Al(OH).sub.3, nH.sub.2O LiCl2Al(OH).sub.3, nH.sub.2O LiCl2Al(OH).sub.3, nH.sub.2O Brine cohesion test, 15% 15% 15% destruction % Water cohesion test 25% 25% 25% destruction %

[0221] The extrudates obtained according to the comparative example 4 and the compliant examples 5, 6 and 7 as compared with those according to non-compliant preparation methods with the invention, visually have good cohesion, have no or few cracks which may cause swelling detrimental to the cohesion and to the strength of the material when the latter is put into contact with a brine solution or water. Moreover, the extrudates produced according to the invention produce less fines during the mechanical strength test as compared with the extrudates produced according to the comparative example 4.

Example 9 (According to the Invention)

[0222] test of the materials produced according to the comparative example 4 and the compliant examples 5, 6 and 7 in the method for extracting lithium according to the invention.

[0223] The material according to the invention prepared in Example 5 is introduced into a jacketed column in order to form a cylindrical bed with a diameter of 2.5 cm and a height of 30 cm.

[0224] The material is then activated at room temperature T=20 C. with a lithium chloride LiCl solution with a concentration of 0.02 mol/L in a downward flow at a flow rate of 3 BV/h. The total volume of LiCl solution used is 14 BV.

[0225] Once the activation step is completed, loading is carried out by means of a natural brine, the composition of which is given in Table 3.

TABLE-US-00004 TABLE 3 composition of the natural brine used for the loading Na K Li Mg Ca B SO.sub.4 Sr Cl Concen- 4.4 0.24 0.068 0.086 0.040 0.031 0.035 0.001 4.89 tration (mol/L)

[0226] The loading of the activated material by adsorption is carried out by having the natural brine pass over said activated material, at a temperature of 60 C., the temperature being maintained by means of a circulation of heated water in the jacket, with a flow rate of 3 BV/h in an upward flow.

[0227] Under the conditions of the example, the adsorption capacity of the material is 4.7 mg of Li/g of dry solid material for a lithium recovery yield of 93%.

[0228] At the end of the loading, the washing step is practiced by using an aqueous solution of sodium chloride. This solution is prepared with saturation of sodium chloride NaCl at 20 C. The solution is then heated to 60 C. and passed at the same temperature as a downward flow in the column at a flow rate of 3 BV/h for a total amount of 4 BV.

[0229] Next, it is proceeded with the desorption step of the lithium by having a lithium chloride (LiCl) solution with a concentration of 0.02 mol/L pass over said material. This desorption is carried out at a temperature of 20 C. with a flow rate of 3 BV/h and in a downward flow. The eluate containing lithium is recovered between 0.75 and 2.25 BV.

[0230] The composition of the eluate as well as the resulting purification factors are summarized in Table 4.

TABLE-US-00005 TABLE 4 composition of the eluate and purification factors X Na K Li Mg Ca B SO.sub.4 Sr Cl Composition 0.52 3.3 .Math. 10.sup.4 0.11 8.6 .Math. 10.sup.3 4.3 .Math. 10.sup.3 1.0 .Math. 10.sup.3 9.4 .Math. 10.sup.5 8.0 .Math. 10.sup.6 0.66 (mol/L) Purification 10 1000 15 10 50 500 90 10 factor

[0231] The concentrations of elements in the brine and in the eluate are determined by the optical ICP method known to one skilled in the art.

[0232] The CI concentrations in the eluate and the brine are determined by the ion chromatography method known to one skilled in the art.

[0233] The extraction method according to the invention therefore allows selective extraction of lithium from natural brine. The selectivity with respect to lithium is expressed as a purification factor which is equal to the X/Li molar ratio in the initial natural brine divided by the X/Li molar ratio in the eluate and which takes into account the external provision of lithium by the washing solution.

[0234] The obtained results indicate that the solid prepared according to the invention is particularly selective in potassium (K), in strontium (Sr), in boron (B) and in sulfates (SO.sub.4).

[0235] The extrudates obtained according to the comparative Example 4 and the compliant Examples 5, 6 and 7 exhibit sufficient cohesion for a use in a column. Moreover, the materials prepared according to the invention generate less fines during their use. This property is an improvement since it gives the possibility of limiting the pressure drop, limiting the generation of preferential paths and reducing the renewal rate of the material.