Synthesis Method of Aluminum-Based Lithium Ion Sieve and Its Application in the Field of Lithium Extraction from Salt Lakes

Abstract

The present invention provides a synthesis method of an aluminum-based lithium ion sieve and its application in the field of lithium extraction from salt lakes, belonging to the technical field of selectively extracting and recovering lithium from lithium-containing solutions, and comprising the following steps: obtaining a clear and transparent lithium salt solution; impregnating activated alumina in the lithium salt solution; adding an alkaline solution to adjust the pH value; and obtaining the adsorbent through drying, high-temperature steam heat treatment, and drying. The prepared aluminum-based adsorbent can be used for extracting and recovering lithium ions in lithium-containing solutions such as slightly acidic or neutral salt lake brines and oilfield produced waters. The adsorbent can be eluted without damage with pure water, and the adsorption and desorption processes are reversible. It has the advantages of mild use conditions, large adsorption capacity, good stability, and less component loss.

Description

Technical Field

[0001] The present invention relates to the technical field of selectively extracting and recovering lithium from lithium-containing solutions, and particularly relates to a method for synthesizing an aluminum-based lithium ion sieve and its application in the field of lithium extraction from salt lakes. Background Art

[0002] Lithium is one of the key materials for new energy and energy storage technologies. With the rapid development of new energy and energy storage industries such as lithium batteries and electric vehicles, the demand for lithium is increasing day by day. However, due to the characteristics of the main distribution of lithium resources in salt lakes in China and the relatively late development of related lithium extraction processes, the low degree of development has led to an over-dependence on foreign countries of more than 74% in lithium resources. Therefore, the research on methods and technologies for extracting lithium from salt water has become a key demand. The lithium reserves in salt lake brine are rich but the grade is poor, with characteristics such as many impurities and a high magnesium-lithium ratio. Separating lithium ions from magnesium ions in salt lake brine is the key to lithium extraction technology from salt lakes. Among them, the adsorption method adsorbs lithium ions through a selective adsorbent, and after desorbing with fresh water, deeply removing impurities, and evaporating and concentrating, lithium products can be obtained, which is applicable to salt lakes with a high magnesium-lithium ratio.

[0003] Aluminum-based ion sieves are the only lithium extraction adsorbents that have been industrially applied at present because their synthesis process is simple and easy to operate, and the adsorption-desorption process is reversible and can be eluted without loss using pure water. This ion sieve has good memory effect and steric hindrance effect, and the adsorption-desorption process is reversible and can be eluted without loss using pure water. Combining nanofiltration / reverse osmosis, electrodialysis, and chemical precipitation processes can achieve the production of high-quality battery-grade Li 2 CO 3 However, existing adsorbents have problems such as low adsorption capacity, insufficient stability, and Al dissolution. Among them, porous activated Al 2 O 3 has a large specific surface area and high mechanical strength, and can also maintain its structural stability well after embedding lithium elements. The invention patent applications with application numbers 201480084536.4 and WO2015171109 prepared aluminum-based adsorbents with good crystal forms by injecting lithium salts into activated alumina with a three-dimensional structure. The invention patent application with application number 201810108604.6 synthesized a crystalline aluminum salt lithium ion adsorbent through a hydrothermal reaction, and its adsorption capacity was as high as 11 - 13 mg / g when adsorbed in 200 mg / L lithium chloride for 6 h. The invention patent application with application number CN202010028091.5 prepared an aluminum-based lithium extraction adsorbent by a coprecipitation method, and the working adsorption capacity after forming was about 3 mg / g. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for synthesizing an aluminum-based lithium ion sieve and its application in the field of lithium extraction from salt lakes to solve at least one of the technical problems existing in the above background art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a simple and efficient synthesis method for aluminum-based lithium ion sieve, comprising the following steps: at room temperature, first impregnate a lithium salt solution with a concentration range of 100-600 g / L and activated alumina for 0.5-24 h to obtain a white suspension. Dropwise add an alkaline solution to adjust the pH to 5-10 and stir evenly. The obtained slurry is filtered, dried, treated with high-temperature steam at 300-800 °C, dried, crushed and screened to finally obtain a lithium-inserted aluminum-based intercalation adsorbent. The prepared Li / Al-LDH adsorbent exhibits excellent lithium adsorption performance in slightly acidic salt lakes.

[0007] Optionally, using activated alumina as the carrier; the activated alumina is α-Al 2 O 3 、β-Al 2 O 3 、γ-Al 2 O 3 、δ-Al 2 O 3 、θ-Al 2 O 3 、one or a combination of more than one of gibbsite, bayerite, and the aluminum component content is 50-80 wt%.

[0008] Optionally, the metal lithium salt includes: Li 2 SO 4 、LiCl、LiCl.H 2 O、LiOH、LiOH.H 2 O、LiNO 3 、one or a combination of more than one of them, and the lithium component content is 0.5-10 wt%.

[0009] Optionally, adjust the pH value of the system by adding an alkali solution, where the alkali is: urea, ammonia water, NaOH, Na 2 CO 3 、one or more of them. The concentration of the alkali solution is 0.01-1 mol / L, and the adjusted pH value is between 6-10.

[0010] Optionally, the drying temperature is preferably 60-120 °C, and the drying time is preferably 2-12 h.

[0011] Optionally, the calcination temperature is preferably 400-800 °C, and the calcination time is preferably 2-12 h.

[0012] Optionally, the calcination atmosphere is high-temperature steam or a mixed gas of one or more of helium, argon, and nitrogen.

[0013] In a second aspect, the present invention provides an application of the aluminum-based lithium ion sieve adsorbent in extracting lithium from acidic salt lakes.

[0014] The acidic or neutral salt lake brine comes from simulated brine prepared in the laboratory, where the concentration of Li + is 50 - 500 ppm, the concentration of Na + is 1000 - 20000 ppm, the concentration of Mg 2+ is 100 - 120000 ppm, the concentration of K + is 100 - 5000 ppm, the concentration of Ca 2+ is 20 - 12000 ppm, the concentration of SO 4 2- is 100 - 10000 ppm, and the concentration of Cl - is 20000 - 40000 ppm.

[0015] The pH value of the simulated salt lake brine is 4 - 8.

[0016] The adsorbent used for extracting lithium resources from the simulated salt lake is used to treat Li in the brine + with a concentration of 50 - 500 ppm. The adsorption conditions are as follows: normal temperature and pressure, the dosage of the adsorbent is 1 - 10 g / L, and the shaking table is used for dispersion adsorption for 1 - 8 h.

[0017] Advantages of the present invention: The reagents used are non-toxic and harmless, non-corrosive, do not require high temperature and high pressure, have low requirements for equipment, and do not produce harmful by-products; the method is simple and easy to operate. First, Li is adsorbed on the surface and pores of alumina + , and then through means such as alkali etching and high-temperature dealumination, lithium is embedded in the adsorbent framework structure without loss, effectively avoiding raw material loss, having a large operation window, and can be quickly realized for batch industrial conversion; using activated alumina with high mechanical strength as the main framework enhances the stability of the material and has a longer service life in the operating environment; it is suitable for extracting lithium resources from slightly acidic salt lake brines, especially salt lakes with a high magnesium-lithium ratio, and can efficiently and highly selectively extract lithium resources.

[0018] The advantages of the additional aspects of the present invention will be more clearly given in the following description part, or can be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is the XRD diagram of the embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the working principle of the adsorbents in Embodiments 1-7 of the present invention and Comparative Cases 1-2. Detailed implementation manners

[0022] The following details the implementation manners of the present invention. Examples of the implementation manners are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The implementation manners described through the drawings below are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0023] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention pertains.

[0024] It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as herein.

[0025] Those skilled in the art of the present technology can understand that, unless specifically stated, the singular forms "a", "an", "the", and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present invention means the presence of the described features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or their groups.

[0026] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0027] For ease of understanding the present invention, the following further explains the present invention with specific embodiments in conjunction with the drawings, and the specific embodiments do not constitute a limitation to the embodiments of the present invention.

[0028] Those skilled in the art should understand that the drawings are only schematic diagrams of the embodiments, and the components in the drawings are not necessarily essential for implementing the present invention.

[0029] AsFigures 1 to 2 As shown in Figures 1 to 2 , the present invention discloses a synthesis method for efficiently synthesizing an aluminum-based adsorbent, comprising the following steps: a) obtaining a clear and transparent lithium salt solution; b) impregnating activated alumina in the lithium salt solution; c) adding an alkaline solution to adjust the pH value; d) obtaining the adsorbent through drying, high-temperature steam heat treatment, and drying.

[0030] Example 1

[0031] 1) Take 44.50 g of anhydrous lithium chloride and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear, and transparent solution;

[0032] 2) Add 10.20 g of activated alumina γ-Al 2 O 3 powder, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0033] 3) Adjust the pH to about 8 with 1 mol / L ammonia water, filter, and place in an oven at 80 °C for drying for 12 h to obtain a white adsorbent precursor;

[0034] 4) Transfer the white precursor to a muffle furnace, introduce steam with nitrogen at a rate of 1 mL / s, control the steam consumption at 0.8 g / h per gram of adsorbent, and calcine at 650 °C for 4 h to obtain Adsorbent Product 1.

[0035] Example 2

[0036] 1) Take 25.20 g of lithium hydroxide and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear, and transparent solution;

[0037] 2) Add 15.80 g of activated alumina gibbsite powder, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0038] 3) Without adjusting the pH, directly filter, and place in an oven at 80 °C for drying for 12 h to obtain a white adsorbent precursor;

[0039] 4) Transfer the white precursor to a muffle furnace, introduce nitrogen at a rate of 1.5 mL / s, control the steam consumption at 0.5 g / h per gram of adsorbent, and calcine at 500 °C for 4 h to obtain Adsorbent Product 2.

[0040] Example 3

[0041] 1) Take 55.00 g of lithium sulfate and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear, and transparent solution;

[0042] 2) Add 10.20 g of activated alumina β-Al 2 O 3 powder, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0043] 3) Adjust the pH to about 8 with 1 mol / L ammonia water, filter, and place in an oven at 80 °C for drying for 12 h to obtain a white adsorbent precursor;

[0044] 4) Transfer the white precursor to an atmosphere furnace, introduce nitrogen at a rate of 1 mL / s, control the water vapor consumption at 1.5 g / h per gram of adsorbent, and calcine at 800 °C for 4 h to obtain the finished adsorbent 3.

[0045] Example 4

[0046] 1) Take 22.25 g of anhydrous lithium chloride and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear, and transparent solution;

[0047] 2) Add 6.37 g of activated alumina α-Al 2 O 3 powder, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0048] 3) Adjust the pH to about 8 with 1 mol / L NaOH, filter, and place in an oven at 80 °C for drying for 12 h to obtain a white adsorbent precursor;

[0049] 4) Transfer the white precursor to an atmosphere furnace, introduce water vapor with nitrogen at a rate of 1 mL / s, control the water vapor consumption at 0.8 g / h per gram of adsorbent, and calcine at 650 °C for 4 h to obtain the finished adsorbent 4.

[0050] Example 5

[0051] 1) Take 70.35 g of lithium nitrate and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear, and transparent solution;

[0052] 2) Add 10.20 g of activated alumina β-Al 2 O 3 powder, stir and impregnate at room temperature for 6 h to obtain a suspension;

[0053] 3) Adjust the pH to about 8 with a mixed alkali solution of 1 mol / L ammonia water and 1 mol / L urea, directly filter, and place in an oven at 80 °C for drying for 12 h to obtain a white adsorbent precursor;

[0054] 4) Transfer the white precursor to an atmosphere furnace, introduce nitrogen at a rate of 1.5 mL / s, control the water vapor consumption at 0.5 g / h per gram of adsorbent, and calcine at 600 °C for 4 h to obtain the finished adsorbent 5.

[0055] Example 6

[0056] 1) Take 63.53 g of hydrated lithium chloride and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear, and transparent solution;

[0057] 2) Add 15.60 g of bayerite powder, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0058] 3) Adjust the pH to 10 with 1 mol / L of Na 2 CO 3 and 0.5 mol / L of NaOH, place in an oven and dry at 80 °C for 12 h to obtain a white adsorbent precursor;

[0059] 4) Transfer the white precursor to a muffle furnace, introduce argon at a rate of 1.5 mL / s, control the water vapor consumption at 2 g / h per gram of adsorbent, and calcine at 700 °C for 4 h to obtain the finished adsorbent 6.

[0060] Example 7

[0061] 1) Take 42.00 g of lithium hydroxide monohydrate and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear and transparent solution;

[0062] 2) Add 15.60 g of gibbsite, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0063] 3) Adjust the pH to 10 with 1 mol / L of urea and 0.1 mol / L of NaOH, place in an oven and dry at 80 °C for 12 h to obtain a white adsorbent precursor;

[0064] 4) Transfer the white precursor to a muffle furnace, introduce argon at a rate of 1 mL / s, control the water vapor consumption at 1 g / h per gram of adsorbent, and calcine at 650 °C for 4 h to obtain the finished adsorbent 7.

[0065] Comparative Example 1:

[0066] 1) Take 44.50 g of anhydrous lithium chloride and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear and transparent solution;

[0067] 2) Add 15.60 g of gibbsite, stir and impregnate at room temperature for 4 h to obtain a suspension;

[0068] 3) Adjust the pH to 8 with 1 mol / L of Na 2 CO 3 and 0.5 mol / L of NaOH, then place it in a reaction kettle with a Teflon inner lining and seal it;

[0069] 4) Transfer the above reaction kettle to an oven at 180 °C, after reacting for 24 h, filter and dry to obtain the comparative adsorbent A.

[0070] Comparative Example 2:

[0071] 1) Take 25.50 g of lithium hydroxide and dissolve it in 200 mL of pure water at room temperature, stir to obtain a colorless, clear and transparent solution;

[0072] 2) Add 10.20 g of activated alumina γ-Al 2 O 3 powder, stir and impregnate at room temperature for 8 h to obtain a suspension;

[0073] 3) After adding 30 g of urea, seal the above-mentioned mixed solution in a reaction kettle with a Teflon inner lining;

[0074] 4) Transfer the above reaction kettle to an oven at 180 °C, filter and dry after reacting for 24 h to obtain the comparative adsorbent B.

[0075] Adsorbent characterization: Put the lithium adsorbent sample into pure water for activation for 2 h. After the Li + desorption equilibrium, filter and dry. Weigh 1 g of the activated sample and put it into 100 mL of a certain simulated salt lake brine (lithium content 200 ppm) for dynamic adsorption and desorption experiments. After the adsorption is stable, test the mass adsorption capacity of the sample for lithium.

[0076] Table 1 shows the working adsorption capacity and selectivity data tables of the adsorbents in Examples 1-7 and Comparative Examples 1-2 of the present invention. The symbol " / " in the table indicates that the corresponding impurity ions are below the detection limit. Due to the high concentration of impurity ions in the solution, for the evaluation of ion selectivity, a desorption experiment is adopted, that is, the mass ratio of desorbed lithium to sodium, magnesium, potassium, calcium and other ions is analyzed. Specific method: Filter the lithium ion adsorbent saturated with adsorption, rinse with ice water, dry, and put it into 100 mL of pure water for desorption, and test the concentration of each ion in the desorption solution.

[0077] Table 1 Statistical table of working adsorption capacity and selectivity of lithium adsorbents

[0078]

[0079] In summary, the synthesis method of the high-efficiency synthetic aluminum-based adsorbent described in the embodiments of the present invention includes the following steps: obtaining a clear and transparent lithium salt solution; impregnating activated alumina in the lithium salt solution; adding an alkaline solution to adjust the pH value; and obtaining the adsorbent through drying, high-temperature steam heat treatment, and drying. The prepared aluminum-based adsorbent can be used for the extraction and recovery of lithium ions in lithium-containing solutions such as slightly acidic or neutral salt lake brines and oilfield produced waters. This adsorbent can be eluted without damage with pure water, and the adsorption and desorption processes are reversible. It has the advantages of mild use conditions, large adsorption capacity, good stability, and less component loss. The present invention prepares the Li / Al-LDHs adsorbent by the methods of impregnation, etching, high-temperature steam dealumination, and lithium intercalation, and obtains an adsorbent with good crystal form. The lithium extraction adsorption capacity in the simulated Laguocuo Salt Lake in Tibet is above 6 mg / g, and the ion selectivity is Li / Na>3, Li / Mg>50, Li / K>10, Li / Ca>50. This method is simple to operate, environmentally friendly and waste-free in the preparation process, and is easy to realize industrial application.

[0080] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, they do not limit the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts should be covered within the protection scope of the present invention.

Claims

1. A synthesis method of an aluminum-based lithium ion sieve, characterized in that, Including: the adsorbent contains Li + An adsorbent with an ion-embedded activated alumina layered structure. The adsorbent is obtained by impregnating powdered activated alumina with a lithium salt, reacting and etching with an alkali mixed solution and stirring to obtain a white precursor, filtering, drying at 60 - 120 °C for 4 - 12 h, and performing high-temperature steam heat treatment at 100 - 800 °C to obtain a Li / Al layered double hydroxide Li / Al-LDHs. The Li / Al-LDHs adsorbent has a lithium-to-aluminum molar fraction of 0.3 - 0.5; wherein, in the high-temperature steam heat treatment, the amount of steam used is 0.2 - 2 g / h per gram of adsorbent, and the carrier gas flow rate is 0.3 - 5 ml / s.

2. The synthesis method of the aluminum-based lithium ion sieve according to claim 1, characterized in that, The activated alumina is α-Al 2 O 3 , β-Al 2 O 3 , γ-Al 2 O 3 , δ-Al 2 O 3 , θ-Al 2 O 3 , one or a combination of more than one of gibbsite, bayerite, kaolin or zeolite, and the alumina component content is 50-90 wt%.

3. The synthesis method of the aluminum-based lithium ion sieve according to claim 1, characterized in that, The lithium salt is Li 2 SO 4 , LiCl, LiCl . H 2 O or LiNO 3 or a combination of one or more thereof, wherein the intercalation amount of lithium is 0.5-10 wt%.

4. The synthesis method of the aluminum-based lithium ion sieve according to claim 1, characterized in that, by adding an alkali solution to adjust the pH value of the system, the concentration of the alkali solution is 0.01 - 5 mol / L, and the adjusted pH value is between 6 and 10.

5. The synthesis method of the aluminum-based lithium ion sieve according to claim 4, characterized in that, The alkaline solution is one or a combination of more than one of urea, ammonia water, NaOH or Na 2 CO 3 .

6. Use of the aluminum-based lithium ion sieve adsorbent prepared by the synthesis method according to any one of claims 1-5 in extracting lithium from salt lakes, wherein the acidic or neutral salt lake brine used is from laboratory-prepared simulated brine, where Li + has a concentration of 50-500 ppm, Na + has a concentration of 1000-20000 ppm, Mg 2+ has a concentration of 100-120000 ppm, K + has a concentration of 100-5000 ppm, Ca 2+ has a concentration of 20-12000 ppm, SO 4 2- has a concentration of 100-10000 ppm, has a concentration of 20000-40000 ppm.

7. For the application according to claim 6, the adsorption conditions are: normal temperature and pressure, the dosage of the adsorbent is 1 - 10 g / L, and the shaking table is used for dispersed adsorption for 1 - 8 h.

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