Method for producing an adsorbent material and method for extracting lithium from saline solutions using the material

Abstract

The present invention relates to the field of solid materials for the adsorption of lithium. In particular, the present invention relates to a new method for the preparation of a crystallized and shaped solid material, preferably in extruded form, of the formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n is between 0.01 and 10, x is between 0.4 and 1, wherein it comprises a step a) of precipitation of boehmite under specific temperature and pH conditions, a step of bringing into contact the precipitate obtained with LiCl, at least one acid extrusion-kneading shaping step, wherein the method also comprises a final hydrothermal treatment step, all of which makes it possible to increase the lithium adsorption capacity, the adsorption kinetics, as well as the lithium/boron selectivity of the materials obtained with respect to the materials of the prior art, when it is used in a lithium extraction method of saline solutions.

Claims

1. A method for preparing a crystalline solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n is between 0.01 and 10, x is between 0.4 and 1, and wherein the method comprises: a) precipitating boehmite, in an aqueous medium, comprising bringing into contact at least one basic precursor and at least one acidic precursor, wherein at least one of the basic or acidic precursors comprises aluminum, in order to obtain a boehmite suspension, wherein the precipitation is carried out at a temperature of between 5 and 35° C., and the amount of the basic precursor is selected in order to obtain a pH of the end of precipitation in a reaction medium of between 7.5 and 9.5, b) bringing into contact the precipitate obtained in a) with at least lithium chloride (LiCl) as lithium source to form a suspension, c) filtering the suspension obtained in b) to obtain a paste, d) drying the paste obtained at the end of c) at a temperature between 20 and 80° C., e) shaping the dried paste obtained in d) by acid extrusion-kneading, wherein the dried paste is kneaded in the presence of an amount of acid of between 0.05 and 5% by weight relative to dry material, wherein the dry material is the weight of the dried paste dried in an oven at 200° C., wherein the acid is an organic or inorganic acid, wherein the dried paste is then subjected to an extrusion, and the shaping the dried paste by acid extrusion-kneading is carried out in the absence of a binder, and f) drying the shaped dried paste obtained at the end of e) at a temperature between 20 and 200° C.

2. The method according to claim 1, wherein the basic precursor is sodium hydroxide (NaOH).

3. The method according to claim 1, wherein the amount of the basic precursor is selected in order to obtain an end of precipitation pH of a) in the reaction medium of between 7.7 and 8.8.

4. The method according to claim 1, wherein b) is carried out in the presence of a quantity of lithium chloride equivalent to a molar ratio of Li/Al between 0.3 and 4.

5. The method according to claim 1, wherein the organic acid used in e) is a carboxylic acid or derivative thereof selected from the group consisting of carboxylic acid salts, alkaline salts and earth salts, alkali metal salts, ammonium salts, and acid anhydrides, while the inorganic acid used in e) is selected from the group consisting of nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid, and mixtures thereof.

6. The method according to claim 5 wherein the acid is an organic acid selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and mixtures thereof.

7. The method according to claim 6, wherein e) is carried out in the presence of oxalic acid.

8. The method according to claim 7, wherein the dried paste is kneaded in the presence of an amount of acid between 0.1 and 2.5% by weight relative to the dry material, wherein the dry material is the weight of the dried paste from e), dried in an oven at 200° C.

9. The method according to claim 1, wherein the basic precursor is selected from the group consisting of sodium aluminate, potassium aluminate, ammonia, sodium hydroxide, and potassium hydroxide.

10. The method according to claim 1, wherein the acidic precursor is aluminum chloride or hydrochloric acid.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the X-ray diffraction pattern of the precipitated boehmites obtained in Examples 1 to 4.

(2) FIG. 3 shows the X-ray diffraction pattern of the precipitated boehmite obtained in Example 5.

(3) FIG. 2 shows the X-ray diffraction pattern of the final solid materials obtained in extruded form respectively in Examples 1 to 4.

(4) FIG. 4 shows the X-ray diffraction pattern of the final solid material obtained in the form of extrudates in Example 5.

(5) FIG. 5 shows the saturation curve according to Example 9, made from the extrudates obtained in Examples 1 to 8.

(6) The invention is illustrated by the following examples which in no way present a limiting character.

EXAMPLES

Example 1 (According to the Invention)

(7) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=0.6, according to a synthetic method according to the invention, wherein the bringing into contact step b) is carried out with an Li/Al ratio of 0.5 and the shaping step is carried out by acid extrusion-kneading.

(8) 1/Precipitation of Boehmite AlOOH

(9) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3,6H.sub.2O) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step. This cake is suspended in a 3 L beaker with 320 mL of water.

(10) A sample of the precipitate obtained is taken from the reaction medium. The XRD (FIG. 1) of the precipitate shows that the precipitate obtained in example 1 is In fact a boehmite precipitate. The boehmite precipitate obtained in Example 1 is poorly crystallized.

(11) The crystallite size of the boehmite obtained is measured according to the Sherrer method:

(12) Size according to [020]=0.6±0.1 (nm); Size according to [120]=1.4±0.1 (nm)

(13) 2/Addition of Lithium Chloride LiCl.

(14) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, wherein this corresponds to an Li/Al molar ratio of 0.5, and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h.

(15) Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(16) The solid material thus prepared is characterized by the formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6, according to a synthetic method according to the invention.

(17) The shaping step is performed by kneading then extrusion. For the kneading step, 35.5 g of paste obtained above is introduced into a Brabender-type kneader (bowl volume 80 ml) with 1.88 g of oxalic acid solution at 100 g/l which corresponds to 1% by weight of oxalic acid relative to the dry matter, wherein the dry material is the weight of the paste resulting from the preceding drying, dried in an autoclave at 200° C. for 6 hours. A supplement of water of approximately 4.7 g is added in order to obtain a cohesive, homogeneous and extrudable paste. The kneading is continued at the same speed for 20 minutes after the end of the addition of acid and water.

(18) The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(19) Extrudates of the solid material having good cohesion and appearance are obtained. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extrudates of the solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25, obtained in Example 1 (FIG. 2).

(20) The extrudates obtained are also characterized by the following measures:

(21) Elemental analysis shows a good Li/Al/Cl stoichiometry corresponding to the composition of an (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O structure.

(22) Al=24.8% weight; Li=1.9% weight; Cl, =9.8% weight.

(23) The extrudates obtained according to Example 1 have good visual cohesion, have no or few cracks and offer both very good cohesion and very good mechanical strength when they are in contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 2 (According to the Invention)

(24) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=0.6, according to a synthetic method according to the invention, wherein the contacting step b) is carried out with an Li/Al ratio of 0.5 and the shaping step is carried out by acid extrusion-kneading.

(25) 1/Precipitation of Boehmite AlOOH

(26) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3,6H.sub.2O) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step. This cake is suspended in a 3 L beaker with 320 mL of water.

(27) A sample of the precipitate obtained is taken from the reaction medium. The XRD (FIG. 1) of the precipitate shows that the precipitate obtained in Example 1 is, in fact, a boehmite precipitate. The boehmite precipitate obtained in Example 1 is poorly crystallized. The size of the crystallites of the boehmite obtained is measured according to the Sherrer method:

(28) Size according to [020]=0.6±0.1 (nm); Size according to [120]=1.4±0.1 (nm)

(29) 2/Addition of Lithium Chloride LiCl.

(30) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, wherein this corresponds to an Li/Al molar ratio of 0.5, and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h.

(31) Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(32) The solid material thus prepared is characterized by the formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6 according to a synthetic method according to the invention.

(33) The shaping step is performed by kneading and then extrusion. For the kneading step, 35.5 g of paste obtained above is introduced into a Brabender-type kneader (bowl volume 80 ml) with 0.33 g of 85% phosphoric acid solution, which corresponds to 0.5% by weight of phosphoric acid relative to the dry matter, wherein the dry material is the weight of the paste resulting from the preceding drying, dried in an autoclave at 200° C. for 6 hours. An additional 8.2 g of water is added in order to obtain a cohesive, homogeneous and extrudable paste. The kneading is continued at the same speed for 20 minutes after the end of the addition of acid and water.

(34) The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(35) Extrudates of solid material having good cohesion and appearance are obtained. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extrudates of the solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 obtained in Example 2 (FIG. 2).

(36) The extrudates obtained are also characterized by the following measures:

(37) Elemental analysis shows a good Li/Al/Cl stoichiometry corresponding to the composition of an (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O structure.

(38) Al=24.8% weight; Li=1.9% weight; Cl, =9.8% weight.

(39) The extrudates obtained according to Example 2 have good visual cohesion, have no or only few cracks and exhibit both very good cohesion and very good mechanical strength when they are in contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 3 (Comparison with Basic Extrusion-Kneading)

(40) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=0.6, according to a synthetic method according to the invention, wherein the bringing into contact step b) is carried out with an Li/Al molar ratio of 0.5 and the shaping step is carried out by basic extrusion-kneading.

(41) 1/Precipitation of Boehmite AlOOH

(42) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step. The suspension obtained is filtered and then washed with water. The cake is suspended in a 3 L beaker with 320 mL of water.

(43) A sample of the precipitate obtained is taken from the reaction medium. The XRD of the precipitate is identical to the XRD obtained in Example 1 (see FIG. 1) and shows that the precipitate obtained in Example 3 is In fact a boehmite precipitate. The boehmite precipitate obtained in Example 3 is poorly crystalline.

(44) The size of the crystallites of the boehmite obtained is measured according to the Sherrer method:

(45) Size according to [020]=0.6±0.1 (nm); Size according to [120]=1.4±0.1 (nm)

(46) 2/Addition of Lithium Chloride LiCl.

(47) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, wherein this corresponds to an Li/Al ratio of 0.5 and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h.

(48) Filtration and drying in an oven at 80° C. for 8 hours follow the first 2 steps.

(49) 3/Extrusion-Kneading

(50) The shaping step is performed by kneading and then extrusion. For the kneading step, 35.5 g of the paste obtained above is introduced into a Brabender-type kneader (80 ml volume of the tank) with 1.39 g of ammonia solution at 20.18% by weight, which corresponds to 1% by weight of base (NH.sub.4OH) relative to the dry material, wherein the dry material is the weight of the paste resulting from the preceding drying, dried in an autoclave at 200° C. for 6 hours. The ammonia solution is mixed with 16 g of demineralized water and is added in 2 minutes while kneading at 50 rpm. A supplement of water of about 2.7 g is added in order to obtain a cohesive, homogeneous and extrudable paste. The kneading is continued at the same speed for 30 minutes after the end of the addition of ammonia and water.

(51) The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(52) The extrudates of the solid material obtained in Example 3 has good cohesion and a good appearance. According to the X-ray diffraction pattern, an (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected.

(53) The XRD of the final material is identical to the XRD of the material obtained in Example 1 (see FIG. 2).

(54) The extrudates obtained are also characterized by the following measurements:

(55) Elemental analysis shows a good Li/Al/Cl stoichiometry corresponding to the composition of an (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O structure

(56) Al=24.8% weight; Li=1.9% weight; Cl, =9.8% weight.

(57) The extrudates obtained according to Example 3 offer good visual cohesion, have no or only few cracks and have both very good cohesion and very good mechanical strength when they are in contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 4 (According to the Invention)

(58) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=1, according to a synthesis method not according to the invention, wherein the bringing into contact step b) is carried out with an Li/Al ratio of 3.3. The shaping step is carried out by acid extrusion-kneading.

(59) 1/Precipitation of Boehmite AlOOH

(60) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step. The suspension obtained is filtered and then washed with water. The cake is suspended in a 3 L beaker with 320 mL of water.

(61) A sample of the precipitate obtained is taken from the reaction medium. The XRD of the precipitate shows that the precipitate obtained in Example 4 is in fact a boehmite precipitate (FIG. 1). The boehmite precipitate obtained in Example 4 is poorly crystallized.

(62) The size of the crystallites of the boehmite obtained is measured according to the Sherrer method:

(63) Size according to [020]=0.6±0.1 (nm); Size according to [120]=1.4±0.1 (nm)

(64) 2/Addition of Lithium Chloride LiCl.

(65) A solution containing 78.5 g of lithium chloride LiCl supplied by Prolabo is prepared, wherein this corresponds to an Li/Al ratio of 3.3, and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h. Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(66) 3/Extrusion-Kneading

(67) The shaping step is performed by kneading and then extrusion. For the kneading step, 35.5 g of paste obtained above is introduced into a Brabender-type kneader (bowl volume 80 ml) with 1.88 g of oxalic acid solution at 100 g/l which corresponds to 1% by weight of oxalic acid relative to the dry material, wherein the dry material is the weight of the paste resulting from the preceding drying, dried in an autoclave at 200° C. for 6 hours. A supplement of water of approximately 4.7 g is added in order to obtain a cohesive, homogeneous and extrudable paste. The kneading is continued at the same speed for 20 minutes after the end of the addition of acid and water.

(68) The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(69) Extrudates of the solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=1 offer good cohesion while a good appearance is obtained. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extruded solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=1 obtained in Example 4. The DRX of the final material is identical to the XRD of the material obtained in Example 1 (see FIG. 2).

(70) The extrudates obtained are also characterized by the following measurements:

(71) Elemental analysis shows a good Li/Al/Cl stoichiometry corresponding to the composition of an (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O structure

(72) Al=23% weight; Li=3% weight; Cl, =15.1% weight.

(73) The extrudates obtained according to Example 4 offer good visual cohesion, have no or only few cracks and offer both very good cohesion and very good mechanical strength when they are in contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 5 (Comparison: Direct Extrusion without Acid Kneading)

(74) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=1 according to a synthesis method not according to the invention, wherein the shaping step is carried out by direct extrusion, without acid kneading.

(75) 1/Precipitation of Boehmite AlOOH

(76) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlC13) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step. This cake is suspended in a 3 L beaker with 320 mL of water.

(77) A sample of the precipitate obtained is taken from the reaction medium. The XRD (FIG. 1) of the precipitate shows that the precipitate obtained in Example 5 is In fact a boehmite precipitate. The boehmite precipitate obtained in Example 5 is poorly crystallized. The size of the crystallites of the boehmite obtained is measured according to the Sherrer method:

(78) Size according to [020]=2.1±2 (nm); Size according to [120]=2.8±3 (nm)

(79) 2/Addition of Lithium Chloride LiCl.

(80) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, wherein this corresponds to an Li/Al ratio of 0.5 and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h.

(81) Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(82) The solid material thus prepared is characterized by the formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=1 according to a synthetic method according to the invention. The shaping step of the paste obtained is carried out directly after the drying step, without a prior kneading step and in the absence of binder. The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(83) Extrudates of the solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6, offer good cohesion and good appearance. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extruded solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6 obtained in Example 5.

(84) The XRD of the final material is shown in FIG. 2.

(85) The extrudates obtained are also characterized by the following measurements:

(86) Elemental analysis shows a good Li/Al/Cl stoichiometry corresponding to the composition of an (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O structure.

(87) Al=24.8% weight; Li=1.9% weight; Cl, =9.8% weight.

(88) The extrudates obtained according to Example 5 offer good visual cohesion, and have no or few cracks. However, when they are subjected to the strength test described above, they have less good cohesion and mechanical strength than the material obtained in Example 1 according to the invention when they are brought into contact with a brine (percentage destruction about 35% in the cohesion test) or water (percentage destruction about 45% in the cohesion test).

Example 6 Comparison (Boehmite Precipitation at pH=10, and Direct Extrusion without Acid Kneading)

(89) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=0.6 according to a synthesis method not according to the invention, wherein the Boehmite precipitation step is carried out at pH=10. The bringing into contact step b) is carried out with an Li/Al ratio=0.5.

(90) 1/Precipitation of Boehmite AlOOH

(91) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 10. The temperature is maintained at 20° C. throughout the duration of the precipitation step. This cake is suspended in a 3 L beaker with 320 mL of water.

(92) A sample of the precipitate obtained is taken from the reaction medium. The XRD of the precipitate shows that the precipitate obtained in Example 6 is In fact a very well crystallized boehmite precipitate (see FIG. 3). The Size of the Crystallites of the Boehmite Obtained is measured according to the Sherrer method:

(93) Size according to [020]=2.1±2 (nm); Size according to [120]=2.8±3 (nm)

(94) 2/Addition of Lithium Chloride LiCl.

(95) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, wherein this corresponds to an Li/Al ratio of 0.5, and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h. Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(96) The solid material thus prepared is characterized by the (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6 according to a synthetic method according to the invention. The shaping step of the paste obtained is carried out directly after the drying step, without a prior kneading step and in the absence of binder. The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(97) Extrudates of the solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6 offer good cohesion and good appearance. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extruded solid material of (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=1 obtained in Example 6.

(98) The XRD of the final material is shown in FIG. 4.

(99) The extrudates obtained are also characterized by the following measurements:

(100) Elemental analysis shows a good Li/Al/Cl stoichiometry corresponding to the composition of a (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O structure:

(101) Al=24.8% weight; Li=1.9% weight; Cl, =9.8% weight.

(102) The extrudates obtained according to Example 6 visually exhibit good cohesion, have no or only few cracks and exhibit both very good cohesion and very good mechanical strength when they are brought into contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 7: Comparison (Acid Extrusion-Kneading with a Solid Precursor Binder of Alumina

(103) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=0.6, according to a synthetic method according to the invention in which the contacting step b) is carried out with an Li/Al ratio of 0.5 but the shaping step e) is carried out by acid extrusion-kneading in the presence of a solid precursor binder of alumina.

(104) 1/Precipitation of Boehmite AlOOH

(105) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3,6H.sub.2O) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step. The cake is suspended in a 3 L beaker with 320 mL of water.

(106) A sample of the precipitate obtained is taken from the reaction medium. The precipitate obtained is a precipitate of boehmite. The boehmite precipitate obtained in Example 7 has small crystallites (also called “little crystallized” precipitate).

(107) The size of the crystallites of the boehmite obtained is measured according to the Sherrer method:

(108) Size according to [020]=0.6±0.1 (nm); Size according to [120]=1.4±0.1 (nm)

(109) 2/Addition of Lithium Chloride LiCl.

(110) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, this corresponds to an Li/Al molar ratio of 0.5, and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h. Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(111) The solid material thus prepared is characterized by the formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6 according to a synthetic method according to the invention.

(112) The shaping step is carried out by kneading (in the presence of a solid precursor of alumina, boehmite) and then extrusion. For the kneading step, 35.5 g of paste obtained above is introduced into a Brabender-type kneader (bowl volume 80 ml) with 6.9 g of phosphoric acid 85% by weight and 4.7 g of a Pural SB3 boehmite powder representing 25% weight of solid alumina precursor relative to the dry weight of paste, wherein the dry material is the weight of the paste resulting from the preceding drying, dried in an oven at 200° C. for 6 hours.

(113) An additional amount of water of about 5.4 g is added in order to obtain a cohesive, homogeneous and extrudable paste. The kneading is continued at the same speed for 20 minutes after the end of the addition of boehmite, acid and water.

(114) The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(115) Extrudates of the solid material having good cohesion and appearance are obtained. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extrudates.

(116) The extrudates obtained according to Example 7 visually exhibit good cohesion, have no or only few cracks and exhibit both very good cohesion and very good mechanical strength when they are brought into contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 8: Comparison (Acid Extrusion-Kneading with Excess Acid)

(117) A solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O is prepared, wherein n is between 0.01 and 1 and x=0.6, according to a synthetic method according to the invention, wherein the contacting step b) is carried out with an Li/Al ratio of 0.5, but the shaping step is carried out by acid extrusion-kneading with excess of acid.

(118) 1/Precipitation of Boehmite AlOOH

(119) In a beaker cooled by an ice bath, a solution containing 326 ml of deionized water and 135.6 g of aluminum chloride hexahydrate (AlCl.sub.3,6H.sub.2O) is prepared. Then, with magnetic stirring, 67.5 g of sodium hydroxide (NaOH) are added for 30 minutes to adjust the pH. The pH reached at the end of the synthesis is 8. The temperature is maintained at 20° C. throughout the duration of the precipitation step.

(120) The cake is suspended in a 3 L beaker with 320 mL of water.

(121) A sample of the precipitate obtained is taken from the reaction medium. The precipitate obtained is a precipitate of boehmite. The boehmite precipitate obtained in Example 8 has small crystallites (also called “little crystallized” precipitate). The size of the crystallites of the boehmite obtained is measured according to the Sherrer method:

(122) Size according to [020]=0.6±0.1 (nm); Size according to [120]=1.4±0.1 (nm)

(123) 2/Addition of Lithium Chloride LiCl.

(124) A solution containing 11.9 g of lithium chloride LiCl provided by Prolabo is prepared, this corresponds to an Li/Al molar ratio of 0.5, and 1326 ml of water which is added to the plumped cake. This reaction medium is stirred and heated at 80° C. for 2 h. Filtration and drying in an autoclave at 80° C. for 8 hours follow the first 2 steps.

(125) The solid material thus prepared is characterized by the formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O, wherein n=0.25 and x=0.6 according to a synthetic method according to the invention. The shaping step is performed by kneading and extrusion. For the kneading step, 35.5 g of paste obtained above is introduced into a Brabender-type kneader (bowl volume 80 ml) with 13.2 g of oxalic acid solution at 100 g/l which corresponds to 7% by weight of oxalic acid relative to the dry material, wherein the dry material is the weight of the paste resulting from the preceding drying, dried in an oven at 200° C. for 6 hours. The kneading is continued at the same speed for 20 minutes after the end of the addition of acid.

(126) The paste obtained is shaped using a piston extruder (from MTS) equipped with a cylindrical die 1 mm in diameter.

(127) The extrudates of the solid material offer good cohesion and appearance. An (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O phase is detected on the X-ray diffraction pattern of the extruded solid material of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O.

(128) The extrudates obtained according to Example 8 offer good visual cohesion, have no or only few cracks and exhibit both very good cohesion and very good mechanical strength when they are in contact with a brine (percentage destruction less than 15% in the cohesion test) or water (percentage destruction less than 20% in the cohesion test).

Example 9: Adsorption Capacity and Adsorption Kinetics Test

(129) The kinetics of lithium adsorption by the extrudates and their adsorption capacity is tested by producing a drilling curve also called leakage curve or column saturation curve. A saturation curve is produced for each of the extrudates obtained in Examples 1 to 6: 15 g of solid are placed in a column 10 column volumes of 0.02 mol/L lithium chloride (LiCl) saline solution traverses the closed circuit column until a stable lithium solution concentration is reached a natural solution containing approximately 0.06 mol/L of lithium traverses the column by passing upwards, at a flow rate of 6 BV/h, i.e. six times the volume occupied by the extruded bed in one hour. the lithium concentration is measured at the outlet of the column as a function of the volume of solution passed.

(130) FIG. 5 shows the saturation curves obtained for each of the extrudates obtained in Examples 1, 2 and 4 in accordance with the invention and Examples 3, 5, 6, 7 and 8 not in accordance with the invention.

(131) The results obtained are summarized in Table 1.

(132) TABLE-US-00001 TABLE 1 pH at end Li Capacity Exam- of introduced mg(Li)/g Ratio ples x kneading precipitation (Li/Al) (dry solid) B/Li 1 0.6 Oxalic acid 8 0.5 6.8 0.09 1% 2 0.6 Phosphoric 8 0.5 6.8 0.09 acid 0.5% 3 0.6 basic 8 0.5 6.6 0.2 4 1 Oxalic acid 8 3.3 6 0.09 1% 5 1 direct 8 0.5 6.6 0.09 6 0.6 direct 10 0.5 4.3 0.4 7 0.6 solid 8 0.5 5.0 0.12 precursor binder of alumina 8 0.6 Oxalic acid 8 0.5 5.5 0.13 7%

(133) The extrudates obtained according to Examples 1, 2 and 4 according to the invention are compared with those obtained in Examples 3, 5, 6, 7 and 8 obtained according to preparation methods not in accordance with the invention. The extrudates of Examples 1 and 2 have a lithium adsorption capacity of 6.8 mg (Li)/g (dry solid). The extrusions of Examples 3 and 5 have a lithium adsorption capacity of 6.6 mg (Li)/g (dry solid). The extrudates of Example 4 have a lithium adsorption capacity of 6 mg (Li)/g (dry solid). However, the selectivities in B for Examples 1, 2 and 4 according to the invention are, in particular, better by a factor of 2 compared to Example 3 which does not conform to the invention. The B/Li ratio is 0.09 for Examples 1, 2 and 4 while it is 0.2 for Example 3 and 0.4 for Example 6.

(134) The extrudates obtained in Example 7 according to a preparation method not according to the invention are compared with those of Example 2 according to the invention. The use of a solid precursor binder of alumina composed of a mixture of boehmite and phosphoric acid induces a loss of capacity of the extrudates which goes from 6.8 mg (Li)/g (dry solid) to 5, 0 mg (Li)/g (dry solid).

(135) The extrudates obtained in Example 8 according to a preparation method not according to the invention are compared with those of Example 1 according to the invention. The use of an excess of oxalic acid, here 7%, induces a loss of capacity of the extrudates which goes from 6.8 mg (Li)/g (dry solid) to 5.5 mg (Li)/g (dry solid).